Richard Mainwaring

All Publications

• Major Aortopulmonary Collateral Arteries With Anatomy Other Than Pulmonary Atresia/Ventricular Septal Defect. Annals of thoracic surgery Patrick, W. L., Mainwaring, R. D., Reinhartz, O., Punn, R., Tacy, T., Hanley, F. L. 2017

  Abstract

  Major aortopulmonary collateral arteries (MAPCAs) are frequently found in association with pulmonary atresia with ventricular septal defect (PA/VSD). However, some patients with MAPCAs do not have PA/VSD but have a variety of other "atypical" anatomic diagnoses.This was a retrospective review of patients with MAPCAs and atypical anatomy. The 50 patients with MAPCAs could be divided into two subgroups: (1) single ventricle anatomy (n = 33) and (2) two ventricle anatomy (n = 17).The 33 patients with MAPCAs and single ventricle included 15 with unbalanced complete atrioventricular canal (CAVC), 6 with pulmonary atresia-intact ventricular septum, and 12 with other forms of single ventricle. The initial cardiac operation included unifocalization/shunt in 24 patients and creation of aortopulmonary window or central shunt in 9 patients. There were seven operative and eight late deaths. Sixteen patients have had a bidirectional Glenn procedure and 6 had a Fontan procedure. The 17 patients with MAPCAs and two ventricles included 5 with CAVC, 4 with corrected transposition, 3 with double outlet right ventricle, 3 with scimitar syndrome, and 2 with complex D-transposition. The initial cardiac operation included single-stage complete repair in 5 patients, unifocalization/shunt in 10 patients, and aortopulmonary window in 2 patients. There were two operative and two late deaths. Thirteen patients have achieved complete repair status.The data demonstrate the wide diversity of anatomy seen in patients with MAPCAs when evaluating diagnoses other than PA/VSD. Two-thirds of the patients had single ventricle and was associated with a relatively high mortality.

  View details for DOI 10.1016/j.athoracsur.2017.02.029

  View details for PubMedID 28527961

• Left Ventricular Retraining and Double Switch in Patients With Congenitally Corrected Transposition of the Great Arteries. World journal for pediatric & congenital heart surgery Ibrahimiye, A. N., Mainwaring, R. D., Patrick, W. L., Downey, L., Yarlagadda, V., Hanley, F. L. 2017; 8 (2): 203-209

  Abstract

  Congenitally corrected transposition of the great arteries (CC-TGA) is a complex form of congenital heart defect with numerous anatomic subgroups. The majority of patients with CC-TGA are excellent candidates for a double-switch procedure. However, in the absence of an unrestrictive ventricular septal defect or subpulmonary stenosis, the left ventricle (LV) may undergo involution and require retraining prior to double switch. The purpose of this study was to review our experience with patients having CC-TGA who required LV retraining prior to a double-switch procedure.This was a retrospective review of 24 patients with CC-TGA who were enrolled in an LV retraining program in preparation for a double-switch procedure. The median age at the time of enrollment for retraining was 11 months (range 1 month-24 years). The average left ventricle to right ventricle pressure ratio was 0.39 ± 0.07 prior to intervention. All 24 patients underwent placement of an initial pulmonary artery band (PAB) for LV retraining.Eighteen (75%) of the 24 patients underwent a double-switch procedure with no operative mortality. Of these 18 patients, 9 had a single PAB and 9 required a second band for retraining. Six patients have not undergone a double-switch procedure to date. Five patients are good candidates for a double switch and are 2 weeks, 3 weeks, 4 weeks, 8 months, and 35 months since their last PAB. One patient died from a noncardiac cause 26 months after PAB retightening. The 18 patients who underwent a double switch were followed for an average of 5 ± 1 years (range 0.1-10.3 years). There has been no late mortality, and only 2 patients required further reinterventions.The data demonstrate that LV retraining has been highly effective in this select group of patients with CC-TGA. The data also demonstrate that the results of the double-switch procedure have been excellent at midterm follow-up. These results suggest that LV retraining and double switch offer a reliable strategy option for patients with CC-TGA.

  View details for DOI 10.1177/2150135116683939

  View details for PubMedID 28329464

• Prevalence and Anatomy of Retroesophageal Major Aortopulmonary Collateral Arteries. Annals of thoracic surgery Mainwaring, R. D., Patrick, W. L., Carrillo, S. A., Ibrahimye, A. N., Muralidaran, A., Hanley, F. L. 2016; 102 (3): 877-882

  Abstract

  Major aortopulmonary collateral arteries (MAPCAs) are the sole source of pulmonary blood flow in patients with pulmonary atresia and absent ductus arteriosus. The anatomy of MAPCAs can be highly variable, both in the number of MAPCAs supplying each lung and the anatomic origin and course of the MAPCAs. This study evaluated the prevalence and anatomy of retroesophageal MAPCAs in patients undergoing repair of pulmonary atresia/ventricular septal defect/MAPCAs.This was a concurrent analysis of 68 consecutive patients (March 2013 through October 2015) undergoing a primary surgical procedure for pulmonary atresia/ventricular septal defect/MAPCAs. A detailed analysis of the MAPCA anatomy was made intraoperatively for each patient, including the total number of MAPCAs to each lung and the presence or absence of a retroesophageal course. These data were correlated with the preoperative cardiac catheterization images.A retroesophageal MAPCA was identified during the operation in 45 of the 68 patients (67%), all of which were located on the side opposite the arch. For the 36 patients with a left aortic arch, 77% had a retroesophageal MAPCA compared with 53% of patients with a right arch. Forty-six percent of retroesophageal MAPCAs coursed within the muscular fibers of the esophagus (intraesophageal) and were more common to the left lung than the right (72% vs 32%). A midsegment stenosis was present in 84% of the retroesophageal MAPCAs, and this was more severe when the MAPCAs were intraesophageal than when they were not (80% vs 42%).These data demonstrate that two-thirds of patients had a retroesophageal MAPCA and that there were significant differences in prevalence and anatomy depending on the side of the aortic arch. These data provide important insights into the origin and course of retroesophageal MAPCAs.

  View details for DOI 10.1016/j.athoracsur.2016.03.011

  View details for PubMedID 27209604

• Surgical Repair of 115 Patients With Anomalous Aortic Origin of a Coronary Artery From a Single Institution. World journal for pediatric & congenital heart surgery Mainwaring, R. D., Murphy, D. J., Rogers, I. S., Chan, F. P., Petrossian, E., Palmon, M., Hanley, F. L. 2016; 7 (3): 353-359

  Abstract

  Anomalous aortic origin of a coronary artery (AAOCA) has been associated with myocardial ischemia and sudden death. The past decade has provided important insights into the natural history and typical patterns of presentation. However, there are also a number of unresolved controversies regarding the indications for surgery and the efficacy of that surgery. The purpose of this study was to review our surgical experience with AAOCA in 115 patients at a single institution.One hundred and fifteen patients have undergone surgical repair of AAOCA at our institution. There were 82 males and 33 females, and the median age at surgery was 16 years. Fifty-nine patients had preoperative symptoms of myocardial ischemia, including 56 with exertional chest pain or syncope and 3 sudden death events. Twenty-four patients had associated congenital heart defects. Seven patients had an associated myocardial bridge.Surgical repair was accomplished by unroofing of an intramural coronary in 86, reimplantation in 9, and pulmonary artery translocation in 20. There has been no early or late mortality. Fifty-seven (97%) of the 59 symptomatic patients have been free of any cardiac symptoms postoperatively. Two patients had recurrent symptoms and underwent reoperation (one had revision of the initial repair and one had repair of a myocardial bridge).Surgical repair of AAOCA can be safely performed and is highly efficacious in relieving symptoms of myocardial ischemia. The two "surgical failures" in this series had an anatomic basis and underscore the need to reassess both the proximal and distal anatomy in these patients.

  View details for DOI 10.1177/2150135116641892

  View details for PubMedID 27142404

• Surgical Repair of Pulmonary Atresia With Ventricular Septal Defect and Major Aortopulmonary Collaterals With Absent Intrapericardial Pulmonary Arteries ANNALS OF THORACIC SURGERY Carrillo, S. A., Mainwaring, R. D., Patrick, W. L., Bauser-Heaton, H. D., Peng, L., Reddy, V. M., Hanley, F. L. 2015; 100 (2): 606-614

  Abstract

  One anatomic variant of pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals (PA/VSD/MAPCAs) is characterized by the absence of intrapericardial pulmonary arteries. This anatomy obviates the possibility of incorporating the pulmonary arteries for reconstruction or palliative procedures. The purpose of this study was to evaluate the surgical results in patients undergoing repair of PA/VSD/MAPCAs with absent pulmonary arteries.This was a retrospective review of 35 patients who underwent surgical repair of PA/VSD/MAPCAs with absent pulmonary arteries between 2007 and 2014. The median age at the time of surgery was 3.4 months, and the median weight was 4.9 kg. All patients underwent unifocalization of MAPCAs, with an average of 3.5 ± 1.4 MAPCAs per patient.Twenty-eight of the 35 patients (80%) underwent complete single-stage surgical repair, including unifocalization of MAPCAs, VSD closure, and right ventricle to pulmonary artery conduit. After complete repair, the average right ventricular to aortic pressure ratio was 0.33 ± 0.07. There were no deaths in this subgroup. Seven patients (20%) were not deemed suitable candidates for VSD closure after their unifocalization procedure, and therefore underwent palliation with a central shunt. There was 1 operative death and 1 interim death. Three patients have subsequently undergone complete repair, and 2 are awaiting further evaluation and treatment.The majority of patients with PA/VSD/MAPCAs and absent pulmonary arteries can undergo complete single-stage repair with satisfactory postoperative hemodynamics. These results suggest that unifocalization of MAPCAs can provide a reasonable pulmonary vascular bed in the absence of intrapericardial pulmonary arteries.

  View details for DOI 10.1016/j.athoracsur.2015.03.110

  View details for Web of Science ID 000358798200043

  View details for PubMedID 26138766

• Surgical Technique for Repair of Peripheral Pulmonary Artery Stenosis and Other Complex Peripheral Reconstructions ANNALS OF THORACIC SURGERY Mainwaring, R. D., Ibrahimiye, A. N., Hanley, F. L. 2016; 102 (2): E181-E183

  Abstract

  Surgical reconstruction of peripheral pulmonary artery stenosis is a technically challenging procedure due to the need to access all lobar and segmental branches. This paper describes our surgical approach that entails division of the main pulmonary and separation of the branch pulmonary arteries. This surgical approach can also be utilized for other complex peripheral pulmonary artery reconstructions.

  View details for DOI 10.1016/j.athoracsur.2016.03.028

  View details for Web of Science ID 000380748600030

  View details for PubMedID 27449462

• Surgical Techniques for Repair of Peripheral Pulmonary Artery Stenosis. Seminars in thoracic and cardiovascular surgery Mainwaring, R. D., Hanley, F. L. 2016; 28 (2): 418-424

  Abstract

  Peripheral pulmonary artery stenosis (PPAS) is a rare form of congenital heart disease that is most frequently associated with Williams and Alagille syndromes. These patients typically have systemic level right ventricular pressures secondary to obstruction at the lobar, segmental, and subsegmental branches. The current management of patients with PPAS remains somewhat controversial. We have pioneered an entirely surgical approach for the reconstruction of PPAS. This approach initially entailed a surgical patch augmentation of all major lobar branches and effectively reduced the right ventricular pressures by more than half. This was the first report demonstrating an effective approach to this disease. Over the past 5 years, we have gradually evolved our technique of reconstruction to include segmental and subsegmental branch stenoses. An important technical aspect of this approach entails the division of the main pulmonary and separation of the branch pulmonary arteries to access the lower lobe branches. Pulmonary artery homograft patches are used to augment hypoplastic pulmonary artery branches. In addition, we perform a Heinecke-Miculicz-type ostioplasty for isolated ostial stenoses. The technical details of the surgical approach to PPAS are outlined in this article and can also be used for other complex peripheral pulmonary artery reconstructions.

  View details for DOI 10.1053/j.semtcvs.2016.07.003

  View details for PubMedID 28043454

• Pulmonary Valve Repair for Patients With Acquired Pulmonary Valve Insufficiency ANNALS OF THORACIC SURGERY Said, S. M., Mainwaring, R. D., Ma, M., Tacy, T. A., Hanley, F. L. 2016; 101 (6): 2294-2301

  Abstract

  Pulmonary valve (PV) insufficiency is often an acquired condition after treatment for pulmonary stenosis. It is recognized that PV insufficiency has serious deleterious effects. Although surgical replacement of the PV is efficacious, artificial valves inevitably fail and require re-intervention. The purpose of this study was to summarize our experience with PV repair in patients with acquired PV insufficiency.This was a retrospective review of 16 patients with marked PV insufficiency who underwent PV repair. Thirteen of these patients were born with tetralogy of Fallot (TOF) and had undergone a previous transannular patch repair. Three patients were born with critical pulmonary stenosis and had a surgical valvotomy or balloon valvuloplasty.The 13 patients with TOF had resection of their previously placed transannular patch with re-approximation of the anterior commissure. All 13 patients experienced a marked reduction in the degree of pulmonary insufficiency. None of these patients have experienced any increase in insufficiency during follow-up. The 3 patients with critical pulmonary stenosis had a variety of pathologic findings identified at the surgical procedure. One patient had a large gap between a commissure and underwent closure of that commissure. The second and third patients had torn leaflets repaired with pericardial and Gore-Tex patches (Gore, Inc, Flagstaff, AZ). The degree of PV insufficiency was decreased to mild in all 3 patients. However, 2 of these 3 patients have subsequently had an increase in the degree of pulmonary insufficiency.Patients with TOF who underwent a previous transannular patch may be candidates for bicuspidization of their native PV, and the results of this procedure have been quite stable at follow-up. PV repair for torn leaflets was effective in the short term but was less stable over time.

  View details for DOI 10.1016/j.athoracsur.2016.01.035

  View details for Web of Science ID 000376502600043

  View details for PubMedID 27083251

• Anatomic Factors Associated With Truncal Valve Insufficiency and the Need for Truncal Valve Repair. World journal for pediatric & congenital heart surgery Patrick, W. L., Mainwaring, R. D., Carrillo, S. A., Ma, M., Reinhartz, O., Petrossian, E., Selamet Tierney, E. S., Reddy, V. M., Hanley, F. L. 2016; 7 (1): 9-15

  Abstract

  Truncus arteriosus is a complex and heterogeneous form of congenital heart defect. Many of the risk factors from several decades ago, including late repair and interrupted aortic arch, have been mitigated through better understanding of the entity and improved surgical techniques. However, truncal valve dysfunction remains an important cause of morbidity and mortality. The purpose of this study was to evaluate the anatomic factors associated with truncal valve dysfunction and the need for truncal valve surgery.This was a retrospective review of 72 infants who underwent repair of truncus arteriosus at our institution. The median age at surgery was nine days, and the median weight was 3.1 kg. Preoperative assessment of truncal valve insufficiency by echocardiography revealed no or trace insufficiency in 30, mild in 25, moderate in 10, and severe in 7. The need for truncal valve surgery was dictated by the severity of truncal valve insufficiency.Sixteen (22%) of the 72 patients undergoing truncus arteriosus repair had concomitant truncal valve surgery. Anatomic factors associated with the need for truncal valve surgery included an abnormal number of truncal valve cusps (P < .005), presence of valve dysplasia (P < .005), and the presence of an anomalous coronary artery pattern (P < .005). Fifteen (94%) of the sixteen patients who underwent concomitant surgery had two or all three of these anatomic factors (sensitivity = 94%, specificity = 85%).This study demonstrates that the presence of specific anatomic factors was closely associated with the presence of truncal valve insufficiency and the need for concomitant truncal valve surgery. Preoperative evaluation of these anatomic factors may provide a useful tool in determining who should undergo concomitant truncal valve surgery.

  View details for DOI 10.1177/2150135115608093

  View details for PubMedID 26714988

• Tetralogy of Fallot Repair: How I Teach It. The Annals of thoracic surgery Mainwaring, R. D., Hanley, F. L. 2016; 102 (6): 1776–81

  View details for DOI 10.1016/j.athoracsur.2016.09.111

  View details for PubMedID 27847033

• Elevated pretransplant pulmonary vascular resistance index does not predict mortality after isolated orthotopic heart transplantation in children: A retrospective analysis of the UNOS database PEDIATRIC TRANSPLANTATION Chiu, P., Schaffer, J. M., Sheikh, A. Y., Ha, R., Reinhartz, O., Mainwaring, R., Reitz, B. A. 2015; 19 (6): 623-633

  Abstract

  OHT is the definitive therapy in end-stage heart failure. Elevated PVRI is considered a relative contraindication to isolated OHT; this assumption is re-evaluated using data from the UNOS database. A retrospective review of de-identified data from the UNOS dataset was performed. There were 1943 pediatric OHT recipients between 10/87 and 12/11 with sufficient data for analysis. Cox regression was performed to examine the effect of baseline characteristics on post-transplant survival. Patients were propensity matched, and Kaplan-Meier survival analysis was performed comparing cohorts of patients using thresholds of 6 and 9 WU × m(2) . PVRI was not a significant predictor of post-transplant outcomes in either univariate or multivariate Cox regression. Kaplan-Meier analysis revealed no difference in survival between both unmatched and propensity-matched OHT recipients. In conclusion, elevated PVRI was not associated with post-transplant mortality in pediatric OHT recipients. A prospective study assessing the current use of PVRI ≥6 as a threshold to contraindicate isolated OHT should be undertaken. Removing this potentially unnecessary restriction on transplant candidacy may make this life-saving therapy available to a greater number of patients.

  View details for DOI 10.1111/petr.12550

  View details for Web of Science ID 000358688400018

• Fate of Right Ventricle to Pulmonary Artery Conduits After Complete Repair of Pulmonary Atresia and Major Aortopulmonary Collaterals ANNALS OF THORACIC SURGERY Mainwaring, R. D., Patrick, W. L., Punn, R., Palmon, M., Reddy, V. M., Hanley, F. L. 2015; 99 (5): 1685-1691

  Abstract

  Surgical repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals (PA/VSD/MAPCAs) requires insertion of a conduit from the right ventricle to the reconstructed pulmonary arteries. Although there is extensive literature on conduit longevity for many forms of congenital heart defects, there is currently limited information for PA/VSD/MAPCAs. It is likely that conduits will have a different longevity in PA/VSD/MAPCAs because pulmonary artery pressures are higher after unifocalization than in other congenital heart defects. The purpose of this study was to evaluate the fate of right ventricle to pulmonary artery conduits after complete repair of PA/VSD/MAPCAs.This was a retrospective review of 103 infants who underwent complete repair of PA/VSD/MAPCAs with insertion of an aortic homograft conduit. The average age at complete repair was 5.1 ± 2.8 months, average conduit size was 13 ± 2 mm, and average conduit z score was a positive 1.6 ± 0.9.Conduit z scores were linearly correlated with increasing homograft conduit size. The average longevity of small homografts (8 to 11 mm) was 15 ± 4 months, medium homografts (12 to 14 mm) was 39 ± 7 months, and large homografts (15 to 17 mm) was 50 ± 14 months. There was a negative correlation between increasing pulmonary artery pressure and conduit longevity.Conduit z scores and conduit size worked synergistically to predict the longevity of right ventricle to pulmonary artery conduits after complete repair of PA/VSD/MAPCAs. Pulmonary artery pressure was an additional modifier of longevity. These data provide a framework for expectations of aortic homograft conduits used in the repair of PA/VSD/MAPCAs.

  View details for DOI 10.1016/j.athoracsur.2014.12.071

  View details for Web of Science ID 000353877900045

  View details for PubMedID 25805573

• Left Ventricular Retraining and Late Arterial Switch for D-Transposition of the Great Arteries. Annals of thoracic surgery Watanabe, N., Mainwaring, R. D., Carrillo, S. A., Lui, G. K., Reddy, V. M., Hanley, F. L. 2015; 99 (5): 1655-1661

  Abstract

  For many decades, patients with d-transposition of the great arteries underwent an atrial switch procedure. Although many of these patients have continued to do well, a subset experience profound right ventricular failure. Some may be candidates for left ventricular (LV) retraining and late arterial switch. The purpose of this study was to review our experience with LV retraining and late arterial switch.This was a retrospective review of 32 patients with d-transposition. Thirty patients underwent a previous atrial switch and subsequently experienced right ventricular failure, whereas 2 presented late (8 months and 6 years) without previous intervention. The median age at the time of enrollment in this program was 15 years. Seven patients proceeded directly to late arterial switch owing to systemic LV pressures. The remaining 25 underwent a pulmonary artery band for LV retraining.Twenty of the 32 (63%) patients enrolled in this program were able to undergo a late arterial switch. There were 2 operative mortalities (10%). Two additional patients survived surgery but died in the early outpatient time period. There has been no late mortality after the arterial switch with a median follow-up of 5 years. Twelve patients underwent one or more pulmonary artery band procedures without evidence of effective LV retraining. There have been 2 early and 3 late (42%) deaths in this subgroup.The outcomes after arterial switch are encouraging and suggest that LV retraining and late arterial switch provide a viable option for this complex group of patients.

  View details for DOI 10.1016/j.athoracsur.2014.12.084

  View details for PubMedID 25817887

• Contemporaneous comparison of the Yasui and Norwood procedures at a single institution. journal of thoracic and cardiovascular surgery Carrillo, S. A., Mainwaring, R. D., Schaffer, J. M., Wright, G., Maeda, K., Hanley, F. L., Reddy, V. M. 2015; 149 (2): 508-513

  Abstract

  It is recognized that there are numerous anatomic variants that result in hypoplastic left heart physiology. One such variant includes critical aortic stenosis or atresia, a hypoplastic aortic arch, and a reasonably well-developed left ventricle due to the presence of a ventricular septal defect. These patients are candidates for 1 of 3 surgical options: (1) a Norwood procedure followed by a single-ventricle pathway; (2) a Norwood procedure followed by a Rastelli procedure (2-stage Yasui); or (3) a single-stage Yasui procedure. Because 2 of the 3 options include a Norwood procedure as the initial step, the purpose of this study was to evaluate the contemporaneous results of the Yasui and Norwood procedures at a single institution.This was a retrospective review of patients who underwent a Yasui or Norwood procedure at Lucile Packard Children's Hospital between 2004 and 2013. Eighteen patients underwent a Yasui, of whom 15 had a single-stage procedure and 3 had a 2-stage procedure. During this time frame, 113 patients underwent a Norwood procedure. Kaplan-Meier survival curves and freedom from reoperation were compared for the 2 procedures.The operative mortality (using the Society of Thoracic Surgeons definition) for the single-stage Yasui was 6.7% compared with 16% for the Norwood procedure (P < .05); survival was 85% versus 62% at 1 year, 85% versus 60% at 3 years, and 85% versus 58% at 5 years, respectively (log-rank P = .06). The average interval to first reoperation was 13.5 ± 3 months versus 4.5 ± 1 months for the Yasui and Norwood procedures, respectively (P < .001).The Yasui procedure had a significantly lower operative mortality compared with the Norwood procedure. Early and midterm survival was also higher in the Yasui group versus the Norwood followed by a single ventricle pathway. These results indicate that the Yasui procedure has significant midterm benefits compared with the Norwood procedure and should be pursued when the anatomy is amenable for this approach.

  View details for DOI 10.1016/j.jtcvs.2014.09.120

  View details for PubMedID 25451485

• Surgical repair of anomalous aortic origin of a coronary artery†. European journal of cardio-thoracic surgery Mainwaring, R. D., Reddy, V. M., Reinhartz, O., Petrossian, E., Punn, R., Hanley, F. L. 2014; 46 (1): 20-26

  Abstract

  Anomalous aortic origin of a coronary artery (AAOCA) is a rare congenital heart defect that has been associated with myocardial ischaemia and sudden death. There is an ongoing controversy over the indications for surgical intervention and the efficacy of that treatment compared with the natural history. The purpose of this study was to evaluate the medium-term results of surgical repair of AAOCA.Seventy-six patients underwent surgical repair of AAOCA at our institution from 1999 to 2013. There were 55 males and 21 females, and the median age at surgery was 15 years. Forty-seven (62%) of the 76 patients had an anomalous right coronary artery, 27 had an anomalous left coronary and 2 had an eccentric single coronary ostia. Forty-one patients had preoperative symptoms of myocardial ischaemia.Surgical repair was accomplished by unroofing of an intramural coronary in 55, reimplantation in 7 and pulmonary artery translocation in 14. There has been no early or late mortality, with a median duration of follow-up of 6 years. One patient presented with severe myocardial ischaemia and subsequently underwent heart transplantation a year following AAOCA surgery. The remaining patients have all remained free of cardiac symptoms.The results of this study demonstrate two major principles. First, surgical repair of AAOCA is quite safe in centres that take care of a significant number of patients with this entity. Secondly, the surgery is highly effective in eliminating symptoms of myocardial ischaemia. The growing amount of data on postoperative patients suggests that surgical repair can prevent the adverse events seen in the untreated 'natural' history. Based on these observations, it is our current recommendation that all teenagers identified with AAOCA should undergo surgical repair.

  View details for DOI 10.1093/ejcts/ezt614

  View details for PubMedID 24431169

• Completion of the Three-Stage Fontan Pathway Without Cardiopulmonary Bypass. World journal for pediatric & congenital heart surgery Mainwaring, R. D., Reddy, V. M., Hanley, F. L. 2014; 5 (3): 427-433

  Abstract

  The three-stage surgical approach is now accepted as the standard for management of children born with functional single ventricle. However, there is little consensus on the cardiopulmonary bypass strategies employed for these procedures. We have attempted to avoid cardiopulmonary bypass in patients with single ventricle whenever possible to eliminate the adverse effects that are induced by this process. The purpose of this study was to review our experience in patients who underwent all three stages of the Fontan pathway without ever being exposed to bypass.A total of 52 patients with single ventricle underwent "off-pump" treatment at all three stages of their surgical management. The time period of the study was from 2002 to 2013. There were 31 males and 21 females. Anatomic diagnoses included double inlet left ventricle (n = 11), pulmonary atresia with intact ventricular septum (n = 11), tricuspid atresia (n = 10), double outlet right ventricle (n = 9), and other (n = 11).There was no operative mortality in the 52 patients undergoing Fontan completion. The patients have been followed for an average of 5.1 ± 2.5 years, with one late mortality. The median length of hospital stay for the three stages was 17, 5, and 9 days, respectively. Of the 52 patients, 42 were able to undergo all three stages without the need for a blood transfusion.This series demonstrates the feasibility of achieving a Fontan circulation without patients exposed to cardiopulmonary bypass. There was no operative mortality and low mid-term mortality. It is notable that 80% of patients never required a blood transfusion with this approach. The elimination of cardiopulmonary bypass provides several potential clinical benefits in this highly select subset of patients with single ventricle.

  View details for DOI 10.1177/2150135114536908

  View details for PubMedID 24958046

• Early complete repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals. Annals of thoracic surgery Watanabe, N., Mainwaring, R. D., Reddy, V. M., Palmon, M., Hanley, F. L. 2014; 97 (3): 909-915

  Abstract

  Pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals (PA/VSD/MAPCAs) is a complex and diverse form of congenital heart defect. Although most patients with PA/VSD/MAPCAs can wait until they are 3 to 6 months of age to undergo surgical reconstruction, there are three specific criteria that merit an earlier repair. These 3 criteria are (1) unremitting heart failure; (2) a ductus to one lung and MAPCAs to the other; and (3) hemitruncus to one lung and MAPCAs to the other. The purpose of this study was to evaluate our surgical experience with early complete repair of PA/VSD/MAPCAs.This was a retrospective review of patients undergoing complete repair of PA/VSD/MAPCAs within the first 60 days of life. Twenty-seven patients were identified in our database (2002 to 2013) who met these criteria. Fifteen had congestive heart failure, 9 had a ductus plus MAPCAs, and 3 had hemitruncus plus MAPCAs. The median age at surgery was 5 weeks.There was no operative mortality in this cohort of 27 patients. Hemodynamics at the conclusion of the complete repair demonstrated an average right ventricular peak systolic pressure of 32 ± 5 mm Hg and an average right ventricle to aortic pressure ratio of 0.36 ± 0.06. The median length of hospital stay was 26 days. There have been 2 subsequent mortalities (7%), with a median follow-up duration of 4 years. Eight of the 27 patients have subsequently undergone conduit replacements at our institution. The hemodynamics at the conclusion of the conduit change were statistically unchanged compared with the hemodynamics after complete repair.The data demonstrate that early complete repair of PA/VSD/MAPCAs can be accomplished with low mortality and excellent postoperative hemodynamics. These early hemodynamic results are maintained at medium-term follow-up. We conclude that early complete repair is an appropriate choice for this highly select subgroup of patients.

  View details for DOI 10.1016/j.athoracsur.2013.10.115

  View details for PubMedID 24480261

• Anomalous aortic origin of a coronary artery: a report from the Congenital Heart Surgeons Society Registry. World journal for pediatric & congenital heart surgery Poynter, J. A., Williams, W. G., Mcintyre, S., Brothers, J. A., Jacobs, M. L. 2014; 5 (1): 22-30

  Abstract

  Anomalous aortic origin of a coronary artery (AAOCA) is a common congenital heart lesion that may be rarely associated with myocardial ischemia and sudden death in the young. Evidence-based criteria for managing young patients with AAOCA are lacking. The Congenital Heart Surgeons Society (CHSS) established a multicenter registry of patients with AAOCA aged ≤30 years to develop these criteria.All institutional members of the CHSS are eligible to enroll patients. Patients were enrolled retrospectively if diagnosis of AAOCA occurred between January 1, 1998, and January 20, 2009, and prospectively from January 20, 2009 forward. The first phase of analysis explored possible associations between demographics, symptoms, coronary anatomy, and management using correlation analysis and logistic regression.As of June 2012, 198 patients were enrolled from CHSS member institutions (median age at diagnosis = 10.2 years; 64% male). Data were extracted from clinical records. Fifty-four percent were symptomatic at presentation (most commonly chest pain, N = 78). The AAOCA was diagnosed at autopsy in two patients who presented with sudden death (one with anomalous aortic origin of the left coronary artery [AAOLCA]; one with a single ostium above a commissure giving rise to both left and right coronary arteries). Imaging reports documented anomalous aortic origin of the right coronary artery (AAORCA) in 144 patients, AAOLCA in 51 patients, and AAOLCA/AAORCA in 1 patient. Surgery or autopsy without surgery was performed in 106 patients (71 AAORCA [67%]; 31 AAOLCA [29%]; and 4 AAORCA/AAOLCA [4%]) at a median age of 12.6 years. Overall, 52% of patients with AAORCA versus 67% with AAOLCA had surgery. Most surgical operative reports described an intramural segment of the coronary artery with anomalous origin. Surgery correlated with symptoms, older age, and presence of an intramural segment in the setting of AAOLCA.Management decisions, including surgical referral, are associated with patient symptoms and coronary morphology. Information derived from annual follow-up of surgically and nonsurgically managed patients enrolled in the registry will eventually form the basis for development of evidence-based protocols to address the spectrum of risk and inform clinical decision making in this heterogeneous population of young patients.

  View details for DOI 10.1177/2150135113516984

  View details for PubMedID 24403351

• Repair of anomalous aortic origin of a coronary artery in 113 patients: a Congenital Heart Surgeons' Society report. World journal for pediatric & congenital heart surgery Poynter, J. A., Bondarenko, I., Austin, E. H., DeCampli, W. M., Jacobs, J. P., Ziemer, G., Kirshbom, P. M., Tchervenkov, C. I., Karamlou, T., Blackstone, E. H., Walters, H. L., Gaynor, J. W., Mery, C. M., Pearl, J. M., Brothers, J. A., Caldarone, C. A., Williams, W. G., Jacobs, M. L., Mavroudis, C. 2014; 5 (4): 507–14

  Abstract

  Anomalous aortic origin of a coronary artery (AAOCA) encompasses a wide morphologic spectrum, which has impeded consensus regarding indications for the diverse repair strategies. We constructed a profile of current surgical techniques and explore their application to morphologic variants.Patients<30 years old (n=113) with isolated AAOCA who underwent operations at 29 Congenital Heart Surgeons Society (CHSS) institutions from 1998 to 2012 were identified from the CHSS AAOCA Registry. Operative findings were related to surgical techniques at index repairs by cross-tabulation.Anomalous origin of the left main or left anterior descending coronary artery was present in 33 (29%) patients and of the right coronary artery in 78 (69%) patients; 2 arteries originated directly above the commissure between the left and right sinuses. There were 101 (89%) interarterial and intramural (IA/IM) arteries, 10 (9%) were interarterial but not intramural (IA/NIM) and 2 (2%) were neither interarterial nor intramural. Intramural arteries were unroofed in 100 (88%) operations, usually with intimal tacking after incision (n=47) or excision (n=25) of the common wall. Coronary reimplantation (n=11), pulmonary artery relocation (n=7; 5 for IA/NIM), simple ostioplasty (without unroofing; n=3), coronary artery bypass grafting (n=2), and ostial window (n=1) were less common. In 37 (33%) operations, a valvar commissure was taken down; 33 were resuspended.Current surgical repair of AAOCA is individualized to morphology, particularly the presence of intramural and/or interarterial segments. This report is foundational for future planned CHSS studies that will examine interventional and noninterventional outcomes and ultimately guide management of AAOCA.

  View details for DOI 10.1177/2150135114540182

  View details for PubMedID 25324246

• Innominate artery cannulation and antegrade cerebral perfusion for aortic arch reconstruction in infants and children. World journal for pediatric & congenital heart surgery Nasirov, T., Mainwaring, R. D., Reddy, V. M., Sleasman, J., Margetson, T., Hanley, F. L. 2013; 4 (4): 356-361

  Abstract

  Innominate artery cannulation has been widely adopted as a means to perform aortic arch reconstruction with continuous cerebral perfusion in the newborn. Although this technique has been subsequently utilized in infants and children, there is currently no data regarding the safety or efficacy in these older children. The purpose of this study was to review our experience with innominate artery cannulation for aortic arch reconstruction in patients beyond the neonatal period.This was a retrospective review of 42 infants and children who underwent aortic arch reconstruction using the technique of innominate artery cannulation with continuous cerebral perfusion. Of these procedures, 29 (69%) were primary arch reconstructions, while 13 (31%) were aortic arch reoperations. The median age at surgery was 8 months, and 22 patients underwent concomitant intracardiac repairs.There was no operative mortality in this cohort of 42 patients undergoing aortic arch reconstruction. There was also no overt evidence of neurologic injury. Specifically, none of the patients demonstrated a neurologic deficit, clinical seizure, or unexpected delay in regaining a normal state of consciousness. The median duration of antegrade cerebral perfusion was 34 minutes. The median duration of hospital stay was 11 days. No patient required reoperation on the aortic arch with a median of 45-month follow-up.Innominate artery cannulation is a safe and effective technique for aortic arch reconstruction in nonneonates. We conclude that antegrade cerebral perfusion is a useful technique for aortic arch reconstruction in this patient population.

  View details for DOI 10.1177/2150135113497767

  View details for PubMedID 24327627

• Aortic valve disease in pulmonary atresia and major aortopulmonary collaterals. Annals of thoracic surgery Mainwaring, R. D., Dimeling, G., Punn, R., Hanley, F. L. 2013; 95 (6): 2122-2125

  Abstract

  Aortic valve disease in association with pulmonary atresia, ventricular septal defect, and major aortopulmonary collaterals (PA/VSD/MAPCAs) is an extremely rare combination of congenital heart defects. The presence of aortic stenosis or insufficiency or both imposes an additional physiologic burden that complicates the management of PA/VSD/MAPCAs. This report summarizes our experience with 7 patients who underwent surgical repair of this rare combination of defects.This was a retrospective review of patients who had both aortic valve disease and PA/VSD/MAPCAs. Four patients had predominantly aortic stenosis, 2 patients had aortic insufficiency, and 1 had mixed stenosis and insufficiency. Anatomically, this corresponded to a dysplastic trileaflet valve in 4, bicuspid valve in 2, and quadricuspid valve in 1.Four of the 7 patients underwent aortic valve surgery at the time of their first operation for PA/VSD/MAPCAs. The remaining 3 patients had aortic valve surgery at subsequent operations. All 7 patients are alive, with a median duration of follow-up of 3 years. One patient has required aortic valve replacement 2 years after repair of an insufficient bicuspid valve.This manuscript summarizes our experience with 7 patients who had the rare combination of aortic valve disease and PA/VSD/MAPCAs. Although aortic valve disease has been reported for other conotruncal defects, we believe this is the first report of its presence in association with PA/VSD/MAPCAs.

  View details for DOI 10.1016/j.athoracsur.2013.03.070

  View details for PubMedID 23643545

• Surgical Reconstruction of Pulmonary Stenosis With Ventricular Septal Defect and Major Aortopulmonary Collaterals ANNALS OF THORACIC SURGERY Mainwaring, R. D., Punn, R., Reddy, V. M., Hanley, F. L. 2013; 95 (4): 1417-1421

  Abstract

  Pulmonary stenosis with ventricular septal defect and major aortopulmonary collaterals (PS/VSD/MAPCAs) is an extremely rare form of congenital heart defect. Although it has been assumed that PS/VSD/MAPCAs would be similar to pulmonary atresia (PA) with VSD/MAPCA, there are currently no data to support this conjecture. This study reviewed our surgical experience with reconstruction of PS/VSD/MAPCA.This was a retrospective review of 25 patients (14 boys, 11 girls) who were born with PS/VSD/MAPCA and underwent surgical reconstruction. Preoperative pulmonary angiography was used to define the central branch pulmonary arteries and MAPCA. Patients were a median age of 4 months at the first operation.There was one operative death (4%) in this cohort of 25 patients, and complete repair was achieved in the 24 survivors (96%). There were two distinct subgroups of patients: 11 demonstrated cyanosis in the neonatal timeframe and underwent an initial procedure to augment pulmonary blood flow (+PBF). The remaining 14 patients formed the second group (-PBF). The median age at the first operation was 0.8 months in the +PBF group and 5.2 months in the -PBF group (p<0.005). Complete repair was achieved in 91% of patients in the +PBF group and in 100% in the -PBF group; however, the average number of procedures to achieve complete repair was 2.8 in the +PBF group vs 1.0 in the -PBF group (p<0.005).Outcomes for PS/VSD/MAPCAs as a whole were excellent, with a low surgical mortality and high rate of complete repair. There were two identifiable subgroups with distinctive differences required in their surgical management. These results provide a prognostic outlook for patients with PS/VSD/MAPCAs that can be compared and contrasted with PA/VSD/MAPCAs.

  View details for DOI 10.1016/j.athoracsur.2013.01.007

  View details for Web of Science ID 000317150600039

  View details for PubMedID 23434256

• Hemodynamic Assessment After Complete Repair of Pulmonary Atresia With Major Aortopulmonary Collaterals ANNALS OF THORACIC SURGERY Mainwaring, R. D., Reddy, V. M., Peng, L., Kuan, C., Palmon, M., Hanley, F. L. 2013; 95 (4): 1397-1402

  Abstract

  Pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals (PA/VSD/MAPCAs) is a complex form of congenital heart defect. There are limited data regarding late hemodynamics of patients after repair of PA/VSD/MAPCAs. This study evaluated the hemodynamics of patients who underwent complete repair of PA/VSD/MAPCSs and subsequently returned for a conduit change.This was a retrospective review of 80 children undergoing a right ventricle (RV)-to-pulmonary artery conduit replacement after complete repair of PA/VSD/MAPCAs. All patients underwent preoperative cardiac catheterization to define the cardiac physiology. Patients were an average age of 6.5±1.2 years, and the average interval between complete repair and conduit change was 4.5±1.1 years.The preoperative cardiac catheterization demonstrated an average RV right peak systolic pressure of 70±22 mm Hg and pulmonary artery pressure of 38±14 mm Hg. This pressure gradient of 32 mm Hg reflects the presence of conduit obstruction. After conduit change, the intraoperative RV systolic pressure was 34±8 mm Hg, similar to 36±9 mm Hg at the conclusion of the previous complete repair. The corresponding RV/aortic pressure ratios were 0.36±0.07 and 0.39±0.09, respectively.The data demonstrate that patients who underwent complete repair of PA/VSD/MAPCAs had nearly identical pulmonary artery pressures when they returned for conduit change some 4.5 years later. This finding indicates that the growth and development of the unifocalized pulmonary vascular bed is commensurate with visceral growth. We would hypothesize that complete repair, along with low RV pressures, will confer a long-term survival advantage.

  View details for DOI 10.1016/j.athoracsur.2012.12.066

  View details for Web of Science ID 000317150600036

  View details for PubMedID 23453744

• Surgical reconstruction of peripheral pulmonary artery stenosis in Williams and Alagille syndromes 38th Annual Meeting of the Western-Thoracic-Surgical-Association Monge, M. C., Mainwaring, R. D., Sheikh, A. Y., Punn, R., Reddy, V. M., Hanley, F. L. MOSBY-ELSEVIER. 2013: 476–81

  Abstract

  Peripheral pulmonary artery stenosis is a rare congenital heart defect frequently found in association with Williams and Alagille syndromes. Controversy exists regarding the optimal treatment of peripheral pulmonary artery stenosis, with most centers favoring catheter-based interventions. In contrast, we have preferentially used surgical reconstruction of peripheral pulmonary artery stenosis. The purpose of the present study was to review our experience with surgical reconstruction of peripheral pulmonary artery stenosis.We performed a retrospective review of patients who underwent surgical reconstruction of peripheral pulmonary artery stenosis. A total of 16 patients were identified: 7 had Williams syndrome, 6 had Alagille syndrome, and 3 had no identifiable syndrome. Detailed pulmonary angiography was performed in all patients to define stenoses at the main, branch, lobar, and segmental arterial levels. The mean preoperative right ventricular/left ventricular pressure ratio was 0.88 ± 0.07. The surgical approach was a median sternotomy with cardiopulmonary bypass. All peripheral stenoses were augmented with pulmonary artery homograft tissue. The median age at surgery was 14 months, and concomitant procedures were performed in 9 of the 16 patients.There was 1 operative mortality (6%). The mean right ventricular/left ventricular pressure ratio decreased to 0.40 ± 0.04 postoperatively (P < .005), representing a 55% reduction compared with the preoperative values. The patients were followed up for a median of 5 years. No late mortality occurred and reoperation was not required.The data have demonstrate that this comprehensive surgical approach to the treatment of peripheral pulmonary artery stenosis was associated with low early and no late mortality. Surgical reconstruction of the peripheral pulmonary artery stenosis resulted in a significant decrease in right ventricular pressure. We hypothesize that this reduction in right ventricular pressures will confer a long-term survival advantage for this cohort of patients.

  View details for DOI 10.1016/j.jtcvs.2012.09.102

  View details for Web of Science ID 000313634700030

  View details for PubMedID 23228407

• Prevalence of Anomalous Coronary Arteries in Pulmonary Atresia with Ventricular Septal Defect and Major Aortopulmonary Collaterals. Journal of the American College of Cardiology Muralidaran, A., Mainwaring, R. D., Reddy, V. M., Hanley, F. L. 2013

  View details for DOI 10.1016/j.jacc.2013.04.092

  View details for PubMedID 23871887

• Late Outcomes in Patients Undergoing Aortopulmonary Window for Pulmonary Atresia/Stenosis and Major Aortopulmonary Collaterals ANNALS OF THORACIC SURGERY Mainwaring, R. D., Reddy, V. M., Perry, S. B., Peng, L., Hanley, F. L. 2012; 94 (3): 842-849

  Abstract

  Pulmonary atresia with ventricular septal defect (PA/VSD) and major aortopulmonary collateral arteries (MAPCAs) is a complex form of congenital heart defect. One identifiable subset has small (<2.5 mm) intrapericardial branch pulmonary arteries that are (1) confluent, (2) have normal arborization, and (3) have dual-supplied collateral vessels. When this anatomy is associated with limited pulmonary blood flow, the patients are candidates for creation of an aortopulmonary window to stimulate growth of the pulmonary arteries. The purpose of this study was to review our experience with creation of an aortopulmonary window as the initial palliative procedure.This was a retrospective review of our surgical experience with 35 children undergoing aortopulmonary window creation from 2002 to 2011. Patients were identified by preoperative cardiac catheterization to define the cardiac and pulmonary artery anatomy.There was no mortality in 35 patients undergoing aortopulmonary window creation. These patients have subsequently undergone 78 cardiac procedures (with 2 operative mortalities). Eighteen of these patients have achieved complete repair, 4 patients in a second procedure, 6 patients in a third procedure, 5 patients in a fourth procedure, and 3 patients in a fifth procedure.The data demonstrate that patients can undergo creation of an aortopulmonary window with excellent early results. Few patients were amenable to complete repair at the second operation, and most required multiple reoperations to recruit sufficient arborization. We interpret these counterintuitive results to suggest that hypoplastic central pulmonary arteries and diminished pulmonary blood flow are markers for a less well developed pulmonary vascular bed.

  View details for DOI 10.1016/j.athoracsur.2012.03.061

  View details for Web of Science ID 000308138900031

  View details for PubMedID 22857982

• Surgical outcomes for patients with pulmonary atresia/major aortopulmonary collaterals and Alagille syndrome 25th Annual Meeting of the European-Association-for-Cardio-Thoracic-Surgery (EACTS) Mainwaring, R. D., Sheikh, A. Y., Punn, R., Reddy, V. M., Hanley, F. L. OXFORD UNIV PRESS INC. 2012: 235–41

  Abstract

  Pulmonary atresia with major aortopulmonary collateral arteries (PA/MAPCAs) is a complex congenital heart defect that has undergone significant advances in treatment over the past 15 years. A small subset of patients with PA/MAPCAs have associated Alagille syndrome, which can have an adverse impact on many other organ systems. The purpose of this study was to review our institutional outcomes for the surgical patients with PA/MAPCAs and Alagille syndrome.This was a retrospective review of patients with PA/MAPCA's and Alagille who underwent surgical reconstruction from November 2001 to August 2011. Fifteen patients were identified in our data base. Thirteen had pulmonary atresia with ventricular septal defect (PA/VSD) and two had pulmonary atresia with intact ventricular septum (PA-IVS).There has been no early or late mortality in this cohort of 15 patients with PA/MAPCA' and Alagille syndrome. The patients have undergone a total of 38 cardiac surgical procedures. Ten of the 13 patients with PA/VSD have achieved complete repair, including unifocalization, a right ventricle to pulmonary artery conduit and closure of all intra-cardiac shunts. The three unrepaired patients with PA/VSD remain potential candidates for eventual complete repair, while the two patients with PA-IVS remain viable candidates for a single ventricle pathway. The patients in this series have also undergone 12 major non-cardiac procedures.The data demonstrate that surgical reconstruction of PA/MAPCAs can be successfully achieved in patients with Alagille syndrome. The longer-term prognosis remains guarded on the basis of the multi-organ system involvement of Alagille syndrome.

  View details for DOI 10.1093/ejcts/ezr310

  View details for Web of Science ID 000306365600013

  View details for PubMedID 22402453

• Surgical Reconstruction of Tracheal Stenosis in Conjunction With Congenital Heart Defects Basic Science Forum of the 58th Annual Meeting of the Southern-Thoracic-Surgical-Association Mainwaring, R. D., Shillingford, M., Davies, R., Koltai, P., Navaratnam, M., Reddy, V. M., Hanley, F. L. ELSEVIER SCIENCE INC. 2012: 1266–73

  Abstract

  Surgical reconstruction is the primary method of treating airway obstruction in children. Tracheal stenosis is frequently associated with congenital heart defects, which may further complicate the overall management strategy. The purpose of this study was to review our experience with surgical reconstruction of airway obstruction in conjunction with congenital heart defects.This was a retrospective review of our surgical experience with tracheal stenosis from February 2003 to August 2011. Twenty-seven patients were identified in our database. Six patients had isolated, congenital tracheal stenosis, and 21 had tracheal stenosis in association with congenital heart defects. There were two identifiable subgroups. Thirteen patients had airway stenoses identified concurrently with congenital heart defects and underwent combined repair. The second group comprised 8 patients who had previous correction of their congenital heart defects and experienced delayed presentation of tracheal (n = 6) or bronchial (n = 2) obstruction.The median age at surgery was 9 months. There were 2 postoperative deaths, both in children with single ventricle. The median duration of follow-up for the entire cohort of 25 surviving patients was 4 years. None of the patients have required reoperations on the trachea; 5 have had minor reinterventions.The data demonstrate that tracheal obstruction is frequently found in conjunction with congenital heart defects. Nearly one third of our patients had delayed presentation of airway obstruction that was identified subsequent to previous congenital heart defect repair. Tracheal reconstructive techniques were effective regardless of the cause of the airway obstruction.

  View details for DOI 10.1016/j.athoracsur.2011.12.063

  View details for Web of Science ID 000302120200049

  View details for PubMedID 22381444

• Late Repair of the Native Pulmonary Valve in Patients With Pulmonary Insufficiency After Surgery for Tetralogy of Fallot ANNALS OF THORACIC SURGERY Mainwaring, R. D., Pirolli, T., Punn, R., Hanley, F. L. 2012; 93 (2): 677-679

  Abstract

  Pulmonary regurgitation developing late after tetralogy of Fallot repair is now recognized as a serious threat to the long-term welfare of these patients. This article summarizes our experience with 5 patients who underwent reoperations for treatment of severe pulmonary regurgitation after transannular patch repair of tetralogy of Fallot. In each case, the intraoperative findings revealed anatomy favorable for valve repair and enabled preservation of the native pulmonary valves.

  View details for DOI 10.1016/j.athoracsur.2011.09.016

  View details for Web of Science ID 000299540200069

  View details for PubMedID 22269747

• Anomalous Aortic Origin of a Coronary Artery: Medium-Term Results After Surgical Repair in 50 Patients ANNALS OF THORACIC SURGERY Mainwaring, R. D., Reddy, V. M., Reinhartz, O., Petrossian, E., Macdonald, M., Nasirov, T., Miyake, C. Y., Hanley, F. L. 2011; 92 (2): 691-697

  Abstract

  Anomalous aortic origin of a coronary artery (AAOCA) is a rare congenital heart defect that has been associated with myocardial ischemia and sudden death. Controversies exist regarding the diagnosis, treatment, and long-term recommendations for patients with AAOCA. The purpose of this study is to evaluate the medium-term results of surgical repair for AAOCA.From January 1999 through August 2010, 50 patients underwent surgical repair of AAOCA. The median age at surgery was 14 years (range, 5 days to 47 years). Thirty-one patients had the right coronary originate from the left sinus of Valsalva, 17 had the left coronary originate from the right sinus, and 2 had an eccentric single coronary ostium. Twenty six of the 50 patients had symptoms of myocardial ischemia preoperatively, and 14 patients had associated congenital heart defects. Repair was accomplished by unroofing in 35, reimplantation in 6, and pulmonary artery translocation in 9.There was no operative mortality. The median time of follow-up has been 5.7 years. Two patients were lost to follow-up, and 1 patient required heart transplantation 1 year after AAOCA repair. In the remaining 47 postoperative patients, all have remained free of cardiac symptoms and no one has experienced a sudden death event.The surgical treatment of AAOCA is safe and appears to be highly effective in eliminating ischemic symptoms. These medium-term results are encouraging and suggest that many patients may be able to resume normal activities.

  View details for DOI 10.1016/j.athoracsur.2011.03.127

  View details for Web of Science ID 000293221000050

  View details for PubMedID 21718962

• Congenital Anomalies of the Mitral Valve. In: Mavroudis C, and Backer CL, Eds. Pediatric Cardiac Surgery Fourth Edition, Wiley-Blackwell, Inc. Mainwaring RD, and Lamberti JJ. 2011
• Surgical Results and Follow-up in Patients with Pulmonary Atresia and Multiple Aortopulmonary Collaterals in Association with Total Anomalous Pulmonary Venous Connection. Ann Thorac Surg Mainwaring RD, Reddy VM, Reinhartz O, Punn R, Tacy T, Hanley FL. 2011: 1756-60
• Triiodothyronine Supplementation in Infants and Children Undergoing Cardiopulmonary Bypass (TRICC) A Multicenter Placebo-Controlled Randomized Trial: Age Analysis 82nd National Conference and Exhibitions and Scientific Sessions of the American-Heart-Association Portman, M. A., Slee, A., Olson, A. K., Cohen, G., Karl, T., Tong, E., Hastings, L., Patel, H., Reinhartz, O., Mott, A. R., Mainwaring, R., Linam, J., Danzi, S. LIPPINCOTT WILLIAMS & WILKINS. 2010: S224–S233

  Abstract

  Triiodothyronine levels decrease in infants and children after cardiopulmonary bypass. We tested the primary hypothesis that triiodothyronine (T3) repletion is safe in this population and produces improvements in postoperative clinical outcome.The TRICC study was a prospective, multicenter, double-blind, randomized, placebo-controlled trial in children younger than 2 years old undergoing heart surgery with cardiopulmonary bypass. Enrollment was stratified by surgical diagnosis. Time to extubation (TTE) was the primary outcome. Patients received intravenous T3 as Triostat (n=98) or placebo (n=95), and data were analyzed using Cox proportional hazards. Overall, TTE was similar between groups. There were no differences in adverse event rates, including arrhythmia. Prespecified analyses showed a significant interaction between age and treatment (P=0.0012). For patients younger than 5 months, the hazard ratio (chance of extubation) for Triostat was 1.72. (P=0.0216). Placebo median TTE was 98 hours with 95% confidence interval (CI) of 71 to 142 compared to Triostat TTE at 55 hours with CI of 44 to 92. TTE shortening corresponded to a reduction in inotropic agent use and improvement in cardiac function. For children 5 months of age, or older, Triostat produced a significant delay in median TTE: 16 hours (CI, 7-22) for placebo and 20 hours (CI, 16-45) for Triostat and (hazard ratio, 0.60; P=0.0220).T3 supplementation is safe. Analyses using age stratification indicate that T3 supplementation provides clinical advantages in patients younger than 5 months and no benefit for those older than 5 months. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00027417.

  View details for DOI 10.1161/CIRCULATIONAHA.109.926394

  View details for Web of Science ID 000282294800032

  View details for PubMedID 20837917

• Unusual Manifestations of Vascular Rings JOURNAL OF CARDIAC SURGERY Mainwaring, R. D., Jacobson, J. L., Reinhartz, O., Gates, R. L. 2010; 25 (1): 79-83

  Abstract

  Vascular rings are a relatively rare entity caused by abnormal development of the fetal aortic arches. Most patients with vascular rings present in infancy or early childhood with respiratory (inspiratory) symptoms. The treatment of patients with symptomatic vascular rings is generally straight-forward, focusing on surgical division of the ring. The majority of patients are "cured" by this simple procedure. However, a small percentage of patients do not follow this typical course. The purpose of this manuscript is to review and discuss three patients who demonstrated unusual manifestations of vascular rings. Two patients required reoperation after double aortic arch repair and one had successful treatment of an aberrant right subclavian artery.

  View details for DOI 10.1111/j.1540-8191.2009.00947.x

  View details for Web of Science ID 000273164700023

  View details for PubMedID 19874418

• Double-Orifice Tricuspid Valve in Association with Complete Atrioventricular Septal Defect PEDIATRIC CARDIOLOGY Mainwaring, R. D., Reddy, V. M., Wright, S. B. 2009; 30 (4): 564-565

  View details for DOI 10.1007/s00246-009-9432-3

  View details for Web of Science ID 000266167600038

  View details for PubMedID 19357908

• Octreotide for Management of Chylothorax following Bidirectional Glenn in a Three-Month-Old Infant JOURNAL OF CARDIAC SURGERY Wright, S. B., Mainwaring, R. D. 2009; 24 (2): 216-218

  Abstract

  Chylothorax developing after open heart surgery for congenital heart defects can be a challenging problem. Established therapies are not always efficacious. This report summarizes our experience using octreotide as an adjunct in the management of an intractable chylous effusion.The patient described underwent a bilateral bidirectional cavopulmonary anastomosis at 3 months of age. Postoperatively, the patient demonstrated significant quantities of milky fluid drainage from the right pleural chest tube. Initial management included diuretics, afterload reduction, and a non-fat diet. These maneuvers appeared to be effective. However, the patient experienced a recurrence of the effusion requiring re-admission to the hospital and re-insertion of a right pleural chest tube. Given the recalcitrant nature of the effusion, an infusion of octreotide was begun.An octreotide infusion was begun at 1 mcg/kg/hr and gradually increased to 3 mcg/kg/hr. Chest tube drainage diminished allowing chest tube removal 13 days later. The octreotide infusion was weaned off over the subsequent 10 days without any further effusion problems.Octreotide may be a useful adjunct in the management of intractable chylous effusions following congenital heart surgery.

  View details for DOI 10.1111/j.1540-8191.2008.00803.x

  View details for Web of Science ID 000263694600033

  View details for PubMedID 19267835

• Outcome Analysis for a Small, Start-up Congenital Heart Surgery Program 1st Meeting of the World-Society-for-Pediatric-and-Congenital-Heart-Surgery Mainwaring, R. D., Reddy, V. M., Reinhartz, O., Lamberti, J. J., Jacobson, J. G., Jimenez, D. L., Hanley, F. L. WILEY-BLACKWELL PUBLISHING, INC. 2008: 622–26

  Abstract

  There will be a continuing need to start new congenital heart surgery programs to serve communities experiencing significant population growth. However, small congenital heart programs frequently underperform their larger counterparts. This study summarizes the clinical outcome data for the first 42 months of a small, start-up congenital heart surgery program. Clinical outcomes were summarized from the start of the program in September 2003 through March 2007. Risk adjustment analysis was performed using the risk adjustment in congenital heart surgery (Rachs-1) risk adjustment model and Society of Thoracic Surgeons (STS) congenital database. Three hundred eighty-six operations have been performed during this time period, including 47 newborns, 96 infants, 217 children/adolescents, and 26 adults (greater than 18 years). There have been two operative mortalities (0.5%). Assigning these cases to the Rachs-1 categories, there were 64 level I, 188 level II, 90 level III, 12 level IV cases, with 32 "others." The predicted mortality for the 354 categorized cases calculates to be 17.4 (Rachs-1) and 10.2 (STS). The data demonstrate that a start-up program with a relatively modest surgical volume can achieve satisfactory clinical results. This model has relied upon careful case selection and direct, senior-level surgeon involvement through an affiliation with a university-based program. These results suggest that a small congenital heart surgery program can be successfully started if the circumstances are carefully controlled.

  View details for DOI 10.1111/j.1540-8191.2008.00675.x

  View details for Web of Science ID 000260499400007

  View details for PubMedID 19016985

• Brain natriuretic peptide levels before and after ventricular septal defect repair ANNALS OF THORACIC SURGERY Mainwaring, R. D., Parise, C., Wright, S. B., Juris, A. L., Achtel, R. A., Fallah, H. 2007; 84 (6): 2066-2069

  Abstract

  Brain natriuretic peptide is a relatively recently discovered circulating mediator that has been correlated with the degree of heart failure in adults. This study evaluated the preoperative and postoperative brain natriuretic peptide levels in infants and children undergoing ventricular septal defect repair.The study enrolled 18 infants and children (ages 2 months to 15.6 years) scheduled for surgical repair of their ventricular septal defects. Brain natriuretic peptide levels were drawn preoperatively and then postoperatively at 1, 24, 48, and 72 hours. The amount of shunt (the ratio of pulmonary blood flow [Q(p)]/systemic blood flow [Q(s)]) through the ventricular septal defect was determined by saturation levels performed in the catheterization laboratory or intraoperatively.The preoperative brain natriuretic peptide levels (pg/mL) averaged 78 +/- 57, and the postoperative levels were 168 +/- 241 at 1 hour, 418 +/- 330 at 24 hours, 405 +/- 364 at 48 hours, and 391 +/- 397 at 72 hours. These differences were significant for each postoperative time point compared with preoperative values. Preoperative brain natriuretic peptide and the Q(p)/Q(s) were significantly correlated (age-adjusted R(2) = 0.33, p < 0.001).Brain natriuretic peptide levels have a close correlation with the physiologic volume load caused by ventricular septal defects. The preoperative brain natriuretic peptide levels were also found to be predictive for the postoperative time course of brain natriuretic peptide level changes. These results suggest that brain natriuretic peptide levels may be a useful clinical marker in infants and children with ventricular septal defects.

  View details for DOI 10.1016/j.athoracsur.2007.07.021

  View details for Web of Science ID 000251176300037

  View details for PubMedID 18036937

• Pentalogy of Cantrell: a rare congenital abnormality. JAAPA : official journal of the American Academy of Physician Assistants Dinice, J., Mainwaring, R. D. 2007; 20 (11): 26-27

  View details for PubMedID 18035760

• The extracardiac conduit Fontan operation using minimal approach extracorporeal circulation: Early and midterm outcomes 85th Annual Meeting of the American-Association-for-Thoracic-Surgery Petrossian, E., Reddy, V. M., Collins, K. K., Culbertson, C. B., MacDonald, M. J., Lamberti, J. J., Reinhartz, O., Mainwaring, R. D., Francis, P. D., Malhotra, S. P., Gremmels, D. B., Suleman, S., Hanley, F. L. MOSBY-ELSEVIER. 2006: 1054–63

  Abstract

  Our approach to the extracardiac conduit Fontan operation has evolved over time from full-pump, to partial-pump, to completely off-pump. This study is designed to report our overall experience with the extracardiac conduit Fontan operation and to evaluate the evolution in bypass technique on postoperative outcomes.From September 1992 to April 2005, 285 patients, median age 4.5 years (1.4-44 years), median weight 16 kg (9.4-94 kg), underwent a primary extracardiac conduit Fontan procedure. Early and late outcomes were analyzed for the entire cohort and for 2 patient groups depending on whether an oxygenator was used in the bypass circuit (166 patients; 58%) or not (119 patients; 42%).Early failure (including death and takedown) occurred in 7 patients (2.5%). Prevalence of new early postoperative sinus node dysfunction necessitating a permanent pacemaker was 0.4%, and that of new tachyarrhythmias necessitating discharge home on a regimen of antiarrhythmia medications was 2.5%. Ten-year actuarial freedom from Fontan failure, new sinus node dysfunction necessitating a permanent pacemaker, and reoperation for conduit thrombosis or stenosis was 90%, 96%, and 98%, respectively. Fenestration rate was lower (P = .001) in the no-oxygenator group (8%) than in the oxygenator group (25%). Patients in the no-oxygenator group had lower intraoperative Fontan pressure (12.0 +/- 2.3 vs 13.5 +/- 2.4 mm Hg, P < .001), common atrial pressure (4.6 +/- 1.8 vs 5.3 +/- 1.8 mm Hg, P = .003), and transpulmonary gradient (7.5 +/- 2.1 vs 8.3 +/- 2.2 mm Hg, P = .013) than did the oxygenator group.The extracardiac conduit Fontan operation coupled with minimal use of extracorporeal circulation is associated with favorable intraoperative hemodynamics, low fenestration rate, minimal risk of thrombosis or stenosis, and minimal early and late rhythm disturbance.

  View details for DOI 10.1016/j.jtcvs.2006.05.066

  View details for Web of Science ID 000241497500009

  View details for PubMedID 17059923

• Unifocalization of major aortopulmonary collaterals in single-ventricle patients 42nd Annual Meeting of the Society-of-Thoracic-Surgeons Reinhartz, O., Reddy, V. M., Petrossian, E., Suleman, S., Mainwaring, R. D., Rosenthal, D. N., Feinstein, J. A., Gulati, R., Hanley, F. L. ELSEVIER SCIENCE INC. 2006: 934–39

  Abstract

  Unifocalization of major aortopulmonary collateral arteries (MAPCAs) in pulmonary atresia with ventricular septal defect and intracardiac repair has become the standard of care. However, there are no reports addressing unifocalization of MAPCAs in single-ventricle patients. It is unknown whether their pulmonary vascular bed can be reconstructed and low enough pulmonary vascular resistance achieved to allow for superior or total cavopulmonary connections.We reviewed data on all patients with functional single ventricles and unifocalization procedures of MAPCAs. From 1997 to 2005, 14 consecutive children with various single-ventricle anatomies were operated on.Patients had a median of three surgical procedures (range, 1 to 5). Two patients had absent, all others diminutive central pulmonary arteries, with an average of 3.5 +/- 1.2 MAPCAs. Seven patients (50%) had bidirectional Glenn procedures, and 3 of these had Fontan procedures. Median postoperative pulmonary artery pressures measured 12.5 mm Hg (Glenn) and 14 mm Hg (Fontan), respectively. Six patients are alive today (46%), with 1 patient lost to follow-up. Three patients died early and 3 late after initial unifocalization to shunts. One other patient survived unifocalization, but was not considered a candidate for a Glenn procedure and died after high-risk two-ventricle repair. Another patient with right-ventricle-dependent coronary circulation died of sepsis late after Glenn.In selected patients with functional single ventricles and MAPCAs, the pulmonary vascular bed can be reconstructed sufficiently to allow for cavopulmonary connections. Venous flow to the pulmonary vasculature decreases cardiac volume load and is likely to increase life expectancy and quality of life for these patients.

  View details for DOI 10.1016/j.athoracsur.2006.03.063

  View details for Web of Science ID 000239996300025

  View details for PubMedID 16928512

• Atrial Septal Defects. In: Kaiser LR, Kron IL, and Spray TL, Eds. Mastery of Cardiothoracic Surgery Second Edition. Mainwaring RD, and Lamberti JJ. 2006: 739-749
• The Lexington physicians of General Robert E. Lee SOUTHERN MEDICAL JOURNAL Mainwaring, R. D., Riley, H. D. 2005; 98 (8): 800-804

  Abstract

  General Robert E. Lee has been interpreted by history as one of the most intriguing personalities of the American Civil War era. In more recent years, there has been much speculation regarding General Lee's health during the war and the possible influence this had on his decision making and performance. Lee's personal letters during and after the war provide some documentation about his health condition, albeit through the eyes of a lay person. The history that was recorded by his personal physicians in Lexington, Virginia provides invaluable insights into his medical history. This manuscript focuses on the lives of these two physicians, Drs. Howard Barton and Robert Madison, and their interactions with their famous patient.

  View details for Web of Science ID 000231579600010

  View details for PubMedID 16144175

• The Triiodothyronine for Infants and Children Undergoing Cardiopulmonary Bypass (TRICC) study: design and rationale. American heart journal Portman, M. A., Fearneyhough, C., Karl, T. R., Tong, E., Seidel, K., Mott, A., Cohen, G., Tacy, T., Lewin, M., Permut, L., Schlater, M., Azakie, A. 2004; 148 (3): 393–98

  Abstract

  Cardiopulmonary bypass induces marked and persistent depression of circulating thyroid hormones in infants and children, possibly contributing to postoperative morbidity. Clinical studies have evaluated parenteral triiodothyronine supplementation after cardiopulmonary bypass in children. However, these investigations had relatively small subject numbers as well as age and diagnosis heterogeneity, thereby limiting ability to determine clinical effect. A double-blind, randomized, placebo-controlled trial is needed to define clinical safety and efficacy of triiodothyronine supplementation in infants.The Triiodothyronine for Infants and Children Undergoing Cardiopulmonary Bypass (TRICC) study is a multicenter, randomized, clinical trial designed to determine safety and efficacy of triiodothyronine supplementation in children <2 years of age undergoing surgical procedures for congenital heart disease. Duration of mechanical ventilation after completion of cardiopulmonary bypass is the primary clinical outcome parameter with multiple secondary clinical and hemodynamic parameters. Nearly 200 patients will be randomly assigned to receive either triiodothyronine or placebo. Patient assignment will be performed using a stratified block randomization according to specific preoperative diagnosis.The TRICC study will provide important data regarding the efficacy and safety of triiodothyronine in this age-specific population undergoing surgery for congenital heart disease.

  View details for DOI 10.1016/j.ahj.2004.03.029

  View details for PubMedID 15389224

• Supplementation of thyroid hormone in children undergoing cardiac surgery CARDIOLOGY IN THE YOUNG Mainwaring, R. D., Nelson, J. C. 2002; 12 (3): 211-217

  Abstract

  Triiodothyronine has been introduced as a promising new supplement for patients undergoing open-heart surgery. This manuscript will review the existing literature regarding supplementation with triiodothyronine in children. Infants and children undergoing cardiac surgery experience a profound decrease in levels of free and total triiodothyronine. These decreases are of sufficient magnitude to effect cardiac function. Supplementation with triiodothyronine has been shown to enhance myocardial performance, improve recovery of circulating levels of triiodothyronine, and to result in an increase in mixed venous oxygen saturation. As encouraging as these results are, there is no definitive study which demonstrates that triiodothyronine improves clinical outcome in children. Thus, while triiodothyronine appears to have promise as a supplement for children undergoing open-heart surgery, more studies are needed to establish the efficacy of such therapy scientifically.

  View details for Web of Science ID 000176685800002

  View details for PubMedID 12365165

• Reduction in levels of triidothyronine following the first stage of the Norwood reconstruction for hypoplastic left heart syndrome CARDIOLOGY IN THE YOUNG Mainwaring, R. D., Healy, R. M., Meier, F. A., Nelson, J. C., Norwood, W. I. 2001; 11 (3): 295-300

  Abstract

  Thyroid hormone has important effects on cardiovascular performance. This study was performed to evaluate the changes in levels of triiodothyronine following the first stage of reconstruction for hypoplastic left heart syndrome.We enrolled 14 newborns with hypoplastic left heart syndrome scheduled for first stage reconstruction. Blood samples were obtained pre-, intra-, and post-operatively. Levels of free and total triiodothyronine were determined by radioimmunoassay. Statistical comparison was performed using Wilcoxon's signed rank test.The levels of free triiodothyronine decreased from a baseline of 355+/-31 pg/dl to 205+/-21 pg/dl upon the institution of bypass, and declined to a level of 135+/-9 pg/dl at 24 hours postoperatively. Similarly, levels of total triiodothyronine decreased from 101+/-15 ng/dl to 65+/-4 ng/dl upon the institution of bypass, and continued to decline during the first 24 hours postoperatively. Levels of free and total triiodothyronine had returned to baseline by the fifth postoperative day.The data demonstrate significant decreases in levels of free and total triiodothyronine during the early postoperative period. These changes in levels of thyroid hormone may have adverse effects on cardiac function during this phase of recovery.

  View details for Web of Science ID 000168752600009

  View details for PubMedID 11388624

• Norwood/Batista operation for a newborn with dilated myopathy of the left ventricle JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Mainwaring, R. D., Healy, R. M., Murphy, J. D., Norwood, W. I. 2000; 120 (3): 612-615

  View details for Web of Science ID 000089177500027

  View details for PubMedID 10962428

• Pharmacokinetic evaluation of triiodothyronine supplementation in children after modified Fontan procedure CIRCULATION Mainwaring, R. D., Capparelli, E., Schell, K., Acosta, M., Nelson, J. C. 2000; 101 (12): 1423-1429

  Abstract

  Triiodothyronine (T(3)) supplementation may be a useful adjunct in the management of patients after cardiopulmonary bypass. Limited data are available regarding the use and pharmacokinetics of T(3) in children. The present study was performed to evaluate T(3) pharmacokinetics in a cohort of children undergoing the modified Fontan procedure.A total of 28 patients were enrolled in this randomized, prospective study. The patients were divided into 4 groups: 1 group received a placebo and 3 groups received intravenous T(3) at dosages of 0.4, 0.6, and 0.8 microg/kg, respectively. All 28 patients survived their operative procedures. Two patients developed low cardiac output, and 3 patients had pleural effusions. The median length of hospital stay was 7 days. The mean free T(3) level was 316+/-67 pg/dL after then administration of a placebo. Patients who received T(3) had mean peak free T(3) levels of 972+/-88, 1351+/-299, and 1869+/-281 pg/dL for the dosages of 0.4, 0.6, and 0.8 microg/kg, respectively. The calculated half-life of T(3) was 7 hours.The half-life of intravenous T(3) in children is approximately one-third of that reported for adults. These results provide a framework for studying the efficacy of T(3) supplementation in children undergoing open-heart surgery.

  View details for Web of Science ID 000086143700020

  View details for PubMedID 10736287

• Shoulder pain in a child: a case presentation of ganglioneuroblastoma. Delaware medical journal Mainwaring, R. D., Healy, R. M., REILLY, A. F., Conard, K. A. 2000; 72 (3): 123-125

  Abstract

  A four and one-half year-old child presented with a several month history of shoulder pain. Her workup revealed a large, homogeneous tumor in the apex of the chest. Surgical resection was performed demonstrating ganglioneuroblastoma. This case illustrates an unusual cause of joint discomfort in children.

  View details for PubMedID 10754787

• Effect of accessory pulmonary blood flow on survival after the bidirectional Glenn procedure CIRCULATION Mainwaring, R. D., Lamberti, J. J., Uzark, K., Spicer, R. L., Cocalis, M. W., Moore, J. W. 1999; 100 (19): 151-156

  View details for Web of Science ID 000083605200026

• Extracardiac conduit fontan for children with heterotaxy and functionally single ventricle CARDIOLOGY IN THE YOUNG Mainwaring, R. D., Lamberti, J. J. 1998; 8 (4): 479-485

  Abstract

  Children with functionally single ventricle in the setting of visceral heterotaxy (isomerism) may present a surgical challenge at the time of Fontan completion because of anomalies of systemic and pulmonary venous drainage. We have used an extracardiac conduit in this population to direct inferior caval venous blood to the pulmonary arteries. Over the past five years, nine children with heterotaxy and a functionally single ventricle underwent correction by placement of an extracardiac synthetic (Gore-Tex) conduit. All patients had previously undergone a bidirectional Glenn procedure. Age and weight at the time of insertion of the extracardiac conduit were 26 +/- 15 months, and 11 +/- 2 kilograms, respectively.Of the nine children, six had an uneventful recovery. One developed elevated venous pressures and required a 'fenestration procedure'. Two patients developed pleural effusions. Median length of stay in hospital was 10 days. All children are alive and well, with follow-up of 19 +/- 16 months. There have been no thromboembolic complications.The extracardiac conduit has worked well in our experience for the completion of the Fontan circulation in children with functionally single ventricle in the setting of visceral heterotaxy.

  View details for Web of Science ID 000077254300013

  View details for PubMedID 9855102

• Complement activation and cytokine generation after modified Fontan procedure ANNALS OF THORACIC SURGERY Mainwaring, R. D., Lamberti, J. J., Hugli, T. E. 1998; 65 (6): 1715-1720

  Abstract

  The modified Fontan procedure separates the systemic and pulmonary circulations in patients born with a functional single ventricle. Delayed recovery is frequently observed after this procedure. It was our hypothesis that complement activation or cytokine generation may contribute to the pathophysiology of this problem.We measured activated complement C3, thromboxane B2, interleukin-6, and tumor necrosis factor-alpha levels by immunoassay in 16 patients undergoing Fontan procedure. Patient plasma samples were obtained preoperatively, on initiation of cardiopulmonary bypass, after administration of protamine, and 1, 4, 8, and 24 hours postoperatively.There was no early or late mortality in this cohort of patients. Low cardiac output developed in 3 of 16 patients, and pleural effusions developed in 5. The median length of hospital stay was 9 days. Activated complement C3 levels increased from a baseline of 1,486 +/- 564 to 4,600 +/- 454 ng/mL after cardiopulmonary bypass and administration of protamine, and returned to baseline by 24 hours. The level of interleukin-6 increased from 42 +/- 32 to 176 +/- 22 pg/mL and at 24 hours remained elevated at 71 +/- 15 pg/mL. Neither thromboxane B2 nor tumor necrosis factor-alpha levels increased significantly.The data demonstrate threefold to four-fold increases in activated complement C3 and interleukin-6, indicating that both humoral and cellular systems are affected. It is our conclusion that complement and cytokine activation may contribute to the delayed recovery observed after Fontan procedure.

  View details for Web of Science ID 000074274100050

  View details for PubMedID 9647087

• Separation of omphalopagus twins: Unique reconstruction using syngeneic cryopreserved tissue JOURNAL OF PEDIATRIC SURGERY Canty, T. G., Mainwaring, R., Vecchione, T., Lamberti, J., Collins, D., Lynch, F., Mathewson, J. 1998; 33 (5): 750-753

  Abstract

  Omphalopagus twin girls were admitted for evaluation of possible separation and repair at age 7 days. Prenatal sonographic diagnosis occurred late in the third trimester and was followed by cesarean section delivery shortly thereafter. Results of extensive evaluation over the next 7 days including x-rays, computed tomography and ultrasound scan of the head and torso, and cardiac catheterization showed: the gastrointestinal tracts were separate and normal, the livers were joined but had separate biliary and vascular systems, and the hearts were separate with vastly different anatomy and function. One twin (twin A) had a normal heart with a small insignificant VSD. Twin B had a single ventricle, an incompetent A-V valve, stenotic pulmonic valve, ASD, PDA, and congenital heart block. Hemodynamic support of twin B was almost entirely from twin A. The vascular communications between the two consisted of a major connection between the internal mammary arteries and large arterial and venous connections traversing the joined livers. Because of continued deterioration of twin B, separation was undertaken at age 15 days. The separation included dividing the liver and the multiple large vascular connections. Two teams then reconstructed each twin separately. Twin B began showing signs of cardiac decompensation shortly after separation in spite of placement of a pacemaker, pulmonary artery banding, and ligation of the PDA. Cardiac function rapidly deteriorated and she died. Tissue from her chest wall was cryopreserved and placed in the tissue bank. Twin A underwent closure of her abdomen, and received a temporary bovine pericardial patch over the chest defect. She subsequently underwent placement of a graft of twin B's rib cage to bridge the bony chest defect and skin flap closure. She is presently taking a normal diet and thriving at home at age 18 months. The use of cryopreserved tissue from a syngeneic source provides a unique method of reconstruction in this situation.

  View details for Web of Science ID 000073564000024

  View details for PubMedID 9607489

• Neurodevelopmental outcomes in children with Fontan repair of functional single ventricle PEDIATRICS Uzark, K., Lincoln, A., Lamberti, J. J., Mainwaring, R. D., Spicer, R. L., Moore, J. W. 1998; 101 (4): 630-633

  Abstract

  The purpose of this study was to assess the neurodevelopmental status of children after Fontan repair of functional single ventricle and to examine the relationship between cognitive function and selected patient characteristics.Neurodevelopmental tests including the Stanford-Binet Intelligence (IQ) scale and the Developmental Test of Visual Motor Integration (VMI) were administered to 32 children (26 months to 16 years of age) with complex single ventricle. The mean and distribution of IQ and VMI scores were compared with population norms. The relationship between test scores and patient characteristics was examined utilizing analysis of variance and correlational methods.The majority of children had intellectual function within the normal range (mean, 97.5 +/- 12.1). Below average VMI scores were found in 21.4% of children. There were no significant correlations between intellectual function or visual motor integration ability and preoperative oxygen saturation or age at Fontan. Children who had deep hypothermic circulatory arrest during a prior Norwood procedure tended to have a lower IQ score.Intellectual development in children with Fontan repair of complex heart defects is essentially within the normal range. Visual motor integration deficits may be more prevalent in these children. In our population, the duration and degree of preoperative hypoxemia had no apparent effect on cognitive function.

  View details for Web of Science ID 000072843200011

  View details for PubMedID 9521946

• Changing practice patterns for children with heart disease: a clinical pathway approach. American journal of critical care Uzark, K., Frederick, C., Lamberti, J. J., WORTHEN, H. M., OGINO, M. T., Mainwaring, R. D., Moore, J. W. 1998; 7 (2): 101-105

  Abstract

  Pediatric cardiac care is costly and requires extensive resources. We studied the effect of clinical pathways on practice patterns and patient care outcomes in infants and children hospitalized for cardiac surgery.In consecutive patients admitted for selected cardiac surgical procedures before (n = 69) and after (n = 173) implementation of clinical pathways, outcomes including hospital length of stay, days in the ICU, time to extubation, ordering of blood studies, costs, and readmissions were compared. Data were analyzed for each of five cardiac surgical procedures: repair of an atrial septal defect, repair of a ventricular septal defect, division of a patent ductus arteriosus, repair of tetralogy of Fallot, and neonatal arterial switch operation to correct transposition of the great arteries.A significant reduction in length of hospital stay, including days in the ICU (decreased 1 to 2 days per admission), was achieved after the clinical pathway was implemented. Reductions in average duration of mechanical ventilation ranged from 28% for repair of a ventricular septal defect to 63% for repair of tetralogy of Fallot. The number of blood studies ordered decreased 20% to 30%. A significant reduction in hospital costs for each procedure, ranging from 16% to 29%, was also achieved with no adverse effects on patients' outcomes.Use of clinical pathways with children hospitalized for cardiac surgery can shorten length of stay in the hospital, reduce use of resources, and improve cost-effectiveness with beneficial outcomes for patients.

  View details for PubMedID 9509223

• Mid- to long-term results of the two-stage approach for type B interrupted aortic arch and ventricular septal defect ANNALS OF THORACIC SURGERY Mainwaring, R. D., Lamberti, J. J. 1997; 64 (6): 1782-1785

  Abstract

  Type B interrupted aortic arch with ventricular septal defect is a complex congenital heart defect that may have associated left ventricular outflow tract obstruction. Surgical management has evolved from a two-stage approach to the currently favored single-stage approach. The following data summarize our experience with the two-stage approach over a 15-year period.Between 1980 and 1995, 27 consecutive patients with type B interrupted aortic arch and ventricular septal defect underwent surgical management using the two-stage approach. There were 15 girls and 12 boys; 21 patients had the DiGeorge syndrome.Stage I was performed at a median age of 4 days. Twenty-six (96%) of 27 patients survived first-stage palliation. One patient survived stage I palliation but died before undergoing stage II. Twenty-five patients underwent second-stage repair at a median age of 6 weeks (range, 1 to 46 weeks). There were 2 early deaths and 1 late death. Actuarial analysis demonstrates 1- and 5-year survival rates of 85% and 81%, respectively. Twenty-two survivors have been followed up for an average of 8 +/- 2 years. Freedom from reoperation for arch graft enlargement has been 86% at 3 years and 55% at 5 years. Freedom from reoperation for left ventricular outflow tract obstruction has been 82% at both 3 and 5 years.The two-stage approach can achieve good mid- to long-term palliation of patients with type B interrupted aortic arch and ventricular septal defect. These results should provide a reference from which to gauge the long-term success of the single-stage approach.

  View details for Web of Science ID 000071469400051

  View details for PubMedID 9436572

• Effects of triiodothyronine supplementation following modified Fontan procedure CARDIOLOGY IN THE YOUNG Mainwaring, R. D., Lamberti, J. J., Nelson, J. C., Billman, G. F., Carter, T. L., Schell, K. H. 1997; 7 (2): 194-200

  View details for Web of Science ID A1997XP56200013

• Tetralogy of Fallot repair results in activation of the renin-angiotensin-aldosterone system EUROPEAN HEART JOURNAL Mainwaring, R. D., Lamberti, J. J., Moore, J. W., Billman, G. F., Carter, T. L., Nelson, J. C. 1996; 17 (9): 1421-1425

  Abstract

  Fluid retention is a common problem following transannular patch repair of tetralogy of Fallot. The present study was undertaken to evaluate whether humoral substances may contribute to this process. Patients undergoing tetralogy of Fallot repair using a transannular patch technique were compared to patients undergoing simple ventricular septal defect repair. Hormone levels were determined by radioimmunoassay. Fluid retention was defined as pleural effusions persisting beyond 5 days. The data demonstrate that patients undergoing tetralogy of Fallot repair had elevated levels of anti-diuretic hormone, renin, angiotensin II, and aldosterone as compared to a group with ventricular septal defect. The elevation in hormone levels in the tetralogy of Fallot group was principally accounted for by those who developed effusions postoperatively. These results suggest that activation of the renin angiotensin-aldosterone system may be one of the contributing factors to fluid retention following tetralogy of Fallot repair.

  View details for Web of Science ID A1996VG27600022

  View details for PubMedID 8880028

• Aortopulmonary collateral vessels and prolonged pleural effusions after modified Fontan procedures AMERICAN HEART JOURNAL Spicer, R. L., Uzark, K. C., Moore, J. W., Mainwaring, R. D., Lamberti, J. J. 1996; 131 (6): 1164-1168

  Abstract

  Pleural effusions after the modified Fontan procedure are unpredictable, increase morbidity, and prolong hospital stay. To assess the relation between preoperative characteristics and postoperative pleural drainage, we performed a retrospective study of 71 patients who underwent Fontan procedures. Analyses revealed no significant relation between duration of effusion and age at Fontan, preoperative oxygen saturation, pulmonary artery pressure, ventricular end-diastolic pressure, type of Fontan, or prior cavopulmonary anastomosis. Patients with significant aortopulmonary collateral vessels evidenced by angiographic opacification of the pulmonary arteries or veins had more prolonged pleural drainage. The duration of the pleural drainage was significantly less in patients who had aortopulmonary collateral occlusion.

  View details for Web of Science ID A1996UP98200017

  View details for PubMedID 8644596

• Secundum-type atrial septal defects with failure to thrive in the first year of life JOURNAL OF CARDIAC SURGERY Mainwaring, R. D., Miraliakbar, H., Lamberti, J. J., Moore, J. W. 1996; 11 (2): 116-120

  Abstract

  This article summarizes the case histories of six infants who had isolated secundum-type atrial septal defects (ASDs) and presented with failure to thrive in the first year of life. Patients underwent operative closure of their ASD with the expectation that this would improve their feeding and growth pattern. Five of the six children demonstrated little or no improvement in symptoms following operation. Each of these five patients have subsequently shown signs of developmental delay. Our experience with this group suggests that failure to thrive associated with a secundum ASD will frequently have a noncardiac basis.

  View details for Web of Science ID A1996UR41900007

  View details for PubMedID 8811405

• Factors influencing perioperative morbidity during palliation of the univentricular heart VII Biennial Meeting of the Society-of-Pediatric-Cardiovascular-Surgery Lamberti, J. J., Mainwaring, R. D., Spicer, R. L., Uzark, K. C., Moore, J. W. ELSEVIER SCIENCE INC. 1995: S550–S553

  Abstract

  The modified Fontan procedure has become the treatment of choice for patients born with a univentricular heart. Although the operative mortality has steadily decreased in recent years, the hospital stay is still prolonged in many patients due to fluid retention and pleural effusions.We retrospectively analyzed subsets of patients undergoing the bidirectional cavopulmonary shunt (BDCPS) and modified Fontan procedure in an attempt to define factors influencing operative mortality and morbidity.Multivariate analysis of 64 patients undergoing BDCPS revealed that age 6 months or less, concomitant operation, mean pulmonary pressure of 15 mm Hg or less, and mean pulmonary artery ratio of 1.8:1 or less were not statistically significant indicators of risk. Abnormal pulmonary artery architecture was a significant predictor of early and late death (p < or = 0.01). Retrospective analysis of 71 patients undergoing the modified Fontan procedure revealed no significant relationship between duration of pleural effusions and age at operation, preoperative oxygen saturation, pulmonary artery pressure, ventricular end-diastolic pressure, or prior BDCPS: Patients with important aortopulmonary collateral vessels defined by angiography had prolonged pleural drainage. Selective use of the total extracardiac conduit and the fenestrated Fontan resulted in low overall mortality with no statistical differences between subsets of patients undergoing different modifications of the Fontan procedure.These data indicate that the operative risk for BDCPS or modified Fontan procedure is quite low if a procedure appropriate for the patient is selected. Abnormal pulmonary artery architecture is an important risk factor for death after the BDCPS: Aortopulmonary collateral vessels are associated with fluid retention and pleural effusions after a modified Fontan procedure. Important aortopulmonary collateral vessels should be occluded before or during the modified Fontan procedure.

  View details for Web of Science ID A1995TW27300018

  View details for PubMedID 8604933

• PERCUTANEOUS USE OF STENTS TO CORRECT PULMONARY-ARTERY STENOSIS IN YOUNG-CHILDREN AFTER CAVOPULMONARY ANASTOMOSIS AMERICAN HEART JOURNAL Moore, J. W., Spicer, R. L., Perry, J. C., Mathewson, J. W., Kirkpatrick, S. E., George, L., Uzark, K., MAINWARING, R. L., Lamberti, J. J. 1995; 130 (6): 1245-1249

  Abstract

  Pulmonary artery distortion is a risk factor among candidates for the Fontan procedure. In 57 patients evaluated by catheterization after successful cavopulmonary anastomosis, 8 had proximal left pulmonary artery (LPA) stenosis, either discrete (4 patients) or long segment (4 patients). Median age was 27 months (range 19 to 60 months). Median weight was 11.4 kg (range 9.1 to 20.0). Mean diameter at LPA stenosis was 4.4 +/- 0.4. Proximal right pulmonary artery mean diameter was 10.4 +/- 1.0 mm. After angiographic and hemodynamic assessment, short 11F sheaths were placed in the right internal jugular (6 patients) or subclavian veins (2 patients). Pulmonary artery angioplasty and stent placement were performed. LPA stenoses were enlarged using 10 Palmaz stents dilated to 10 mm (7 patients) or to 12 mm (3 patients). Poststent angiograms showed that narrowest LPA dimensions were significantly enlarged to 9.9 mm +/- 1.0 mm, p < 001). There were no complications. Follow-up studies (catheterizations in 4 patients, echocardiograms in 8 patients) were performed 4 to 9 months after stent implantation. No restenosis was observed. Five patients had completion of their Fontan procedures; three patients are pending Fontan completion. This study demonstrates the efficacy and safety of the percutaneous use of Palmaz stents to correct pulmonary artery stenosis in young children after cavopulmonary anastomosis.

  View details for Web of Science ID A1995TH12600014

  View details for PubMedID 7484776

• BIDIRECTIONAL GLENN - IS ACCESSORY PULMONARY BLOOD-FLOW GOOD OR BAD 67th Scientific Session of the American-Heart-Association Mainwaring, R. D., Lamberti, J. J., Uzark, K., Spicer, R. L. LIPPINCOTT WILLIAMS & WILKINS. 1995: 294–97

  View details for Web of Science ID A1995TE55900050

• RENIN, ANGIOTENSIN-II, AND THE DEVELOPMENT OF EFFUSIONS FOLLOWING BIDIRECTIONAL GLENN AND FONTAN PROCEDURES JOURNAL OF CARDIAC SURGERY Mainwaring, R. D., Lamberti, J. J., Carter, T. L., Moore, J. W., Nelson, J. C. 1995; 10 (2): 111-118

  Abstract

  Pleural effusions are a troublesome complication following bidirectional Glenn and Fontan procedures. It was our hypothesis that effusions may be related to alterations in hormones that regulate fluid homeostasis. We made serial determinations (by radioimmunoassay) of antidiuretic hormone, cortisol, aldosterone, angiotensin II, and renin in patients undergoing bidirectional Glenn (n = 16) and Fontan procedures (n = 24). There were six patients who developed effusions following surgery. These patients had a different endocrinological pattern characterized by persistent elevation in renin (28 +/- 9 vs 9 +/- 5 ng/mL per hour, p < 0.01) and angiotensin II (110 +/- 33 vs 33 +/- 14 ng/L, p < 0.01) on the fifth postoperative day as compared to patients who did not develop effusions. These data demonstrate that patients who develop effusions following bidirectional Glenn and Fontan procedures have activation of their renin-angiotensin system.

  View details for Web of Science ID A1995QR19800003

  View details for PubMedID 7772874

• Tracheoesophageal Compressive Syndromes of Vascular Origin: Rings and Slings. In: Baue AE, Ed. Glenn?s Thoracic and Cardiovascular Surgery Sixth Edition, Stamford, CA. Appleton and Lange. Mainwaring RD, and Lamberti JJ. 1995: 1095-1103
• Palliation of the Univentricular Heart. Heart Surgery. Lamberti JJ, Uzark K, Mainwaring RD, Moore JE, Spicer RL. 1995: 139-149
• DAMUS-KAYE-STANSEL PROCEDURE - MIDTERM FOLLOW-UP AND TECHNICAL CONSIDERATIONS 30th Annual Meeting of the Society-of-Thoracic-Surgeons Carter, T. L., Mainwaring, R. D., Lamberti, J. J. ELSEVIER SCIENCE INC. 1994: 1603–8

  Abstract

  The Damus-Kaye-Stansel operation is useful in the management of complex congenital heart defects. We reviewed our experience with 23 patients who underwent a Damus-Kaye-Stansel procedure. The anastomotic technique was individualized depending on the anatomy. The aortic and pulmonary artery incisions were carried into the sinuses of Valsalva in 9 patients, the aorta was transected in 11 patients, and a patch was used to augment the anastomosis in 13 patients. Concurrent procedures included a Fontan operation (n = 9, mortality = 0), right ventricle-pulmonary artery conduit (n = 5, mortality = 0), bidirectional Glenn procedure (n = 6, mortality = 1), and central aortopulmonary shunt (n = 3, mortality = 2; emergency = 1). Survival is 87% with a median follow-up of 7 years (range, 2 months to 9.2 years). Four patients underwent late revision of the Damus-Kaye-Stansel connection. All survivors are asymptomatic. We conclude that the Damus-Kaye-Stansel connection provides excellent midterm results when the proximal anastomosis is adapted to the anatomy of the patient.

  View details for Web of Science ID A1994PU98600010

  View details for PubMedID 7979722

• SUPPRESSION OF THE PITUITARY-THYROID AXIS AFTER CARDIOPULMONARY BYPASS IN THE NEONATE ANNALS OF THORACIC SURGERY Mainwaring, R. D., Lamberti, J. J., Billman, G. F., Nelson, J. C. 1994; 58 (4): 1078-1082

  Abstract

  Thyroid hormone has numerous effects on cardiovascular function in the adult. The present study was undertaken to evaluate the effects of cardiopulmonary bypass and deep hypothermia on thyroid function in the neonate. Ten newborns were studied preoperatively and postoperatively. The total and free triiodothyronine, total and free thyroxine, thyroid-stimulating hormone, and thyroglobulin levels were measured by immunoassays. The data demonstrated a transient rise in the free thyroxine level associated with and followed by significant reductions in the free and total triiodothyronine, total thyroxine, thyroid-stimulating hormone, and thyroglobulin levels in the early postoperative period. By the fifth postoperative day, the free and total triiodothyronine and total thyroxine levels were returning toward the preoperative levels under the influence of an elevated thyroid-stimulating hormone level. These results suggest that the combination of cardiopulmonary bypass and deep hypothermia can result in a transient suppression of the pituitary-thyroid axis in the neonate.

  View details for Web of Science ID A1994PL57200028

  View details for PubMedID 7944754

• REDUCTION IN TRIIODOTHYRONINE LEVELS FOLLOWING MODIFIED FONTAN PROCEDURE JOURNAL OF CARDIAC SURGERY Mainwaring, R. D., Lamberti, J. J., Carter, T. L., Nelson, J. C. 1994; 9 (3): 322-331

  Abstract

  Diminished cardiac function is a common manifestation following the modified Fontan procedure. Since thyroid hormone has important effects on cardiovascular function, the present study was undertaken to evaluate changes in thyroid hormone levels following this operation. A control group consisting of children undergoing open heart procedures other than a Fontan procedure was also evaluated. Serum total and free triiodothyronine (T3), total and free thyroxine (T4), thyroid stimulating hormone (TSH), and thyroglobulin were measured by immunoassays. The Fontan group demonstrated an initial increase in free T4, while free T3, total T3, total T4, TSH, and thyroglobulin were reduced. Over the subsequent days, free T4 decreased to below the preoperative value. By the fifth and eighth postoperative days, free T3, total T3, free T4, and total T4 remained reduced, while TSH and thyroglobulin began increasing toward the preoperative levels. The control group also demonstrated decreases in free T3 and TSH. However, these values had returned to baseline by the fifth postoperative day. The results indicate that children undergoing open heart surgery have suppression of the pituitary-thyroid axis, and that this is prolonged in patients undergoing Fontan procedure. The decreased levels of T3 following Fontan procedure may have adverse effects on the recovery of patients undergoing this operation.

  View details for Web of Science ID A1994NN76200006

  View details for PubMedID 8054727

• The Bidirectional Glenn: Palliation of the Univentricular Heart. In: Karp RD, Laks H, and Wechsler AS, Eds. Advances in Cardiac Surgery, Vol. 5, St. Louis Mosby-Year Book, Inc. Mainwaring RD, Lamberti JJ, Uzark K. 1994: 115-140
• The bidirectional Glenn procedure: palliation of the univentricular heart. Advances in cardiac surgery Mainwaring, R. D., Lamberti, J. J., Uzark, K. 1994; 5: 115-140

  View details for PubMedID 7509702

• AIRWAY COMPROMISE SECONDARY TO VASCULAR COMPRESSION IN A NEONATE INTERNATIONAL JOURNAL OF PEDIATRIC OTORHINOLARYNGOLOGY TERRIS, M. H., Mainwaring, R. D., Pransky, S. M. 1994; 28 (2-3): 193-197

  Abstract

  Respiratory distress in the neonate may be due to extrinsic tracheobronchial compression. We recently observed a neonate with left mainstem bronchus obstruction resulting in respiratory distress and mediastinal shift. Initial management required intubation and positive pressure ventilation. Bronchoscopic evaluation demonstrated compression of the proximal left main bronchus. The distal bronchus appeared normal. Bronchography, echocardiography and an MRI of the chest confirmed proximal compression of the bronchus and suggested that the cause was an aneurysmal left pulmonary artery and patent ductus arteriosus. With medical therapy there was resolution of the bronchial compression. Re-evaluation by bronchoscopy and echocardiography revealed a normal left main stem bronchus, a normal left pulmonary artery and a closed ductus arteriosus. This clinical scenario suggests that transient pulmonary hypertension may result in significant airway compression due to the proximity of the left main stem bronchus to the left pulmonary artery.

  View details for Web of Science ID A1994MV36000011

  View details for PubMedID 8157418

• COMPARISON OF THE HORMONAL RESPONSE AFTER BIDIRECTIONAL GLENN AND FONTAN PROCEDURES 29TH Annual Meeting of the Society-of-Thoracic-Surgeons Mainwaring, R. D., Lamberti, J. J., Moore, J. W., Billman, G. F., Nelson, J. C. ELSEVIER SCIENCE INC. 1994: 59–64

  Abstract

  Fluid retention is a frequent complication after the bidirectional Glenn and Fontan procedures. It was our hypothesis that this fluid retention may have a hormonal basis. To test this hypothesis, we made serial determinations of antidiuretic hormone, cortisol, aldosterone, angiotensin, and renin before and after operation in patients undergoing a bidirectional Glenn (n = 15) or Fontan (n = 18) procedure. Patients undergoing a bidirectional Glenn procedure had elevations in antidiuretic hormone, cortisol, and aldosterone immediately after operation. However, none of the hormonal elevations persisted by the fifth postoperative day. In contrast, patients undergoing a Fontan procedure had elevations in antidiuretic hormone, cortisol, aldosterone, renin, and angiotensin II in the immediate postoperative period. Five days postoperatively, the renin and angiotensin II levels remained elevated compared with the preoperative values. The data demonstrate that patients undergoing a bidirectional Glenn procedure and those undergoing a Fontan procedure have different patterns of hormonal response. These results suggest that hormonal factors may contribute to fluid retention after these operations.

  View details for Web of Science ID A1994MR31800011

  View details for PubMedID 8279919

• Congenital Anomalies of the Mitral Valve. In: Mavroudis C, and Backer CL, Eds. Pediatric Cardiac Surgery Second Edition, St. Louis Mosby- Year Book, Inc. Lamberti JJ, and Mainwaring RD. 1994: 459-473
• MANAGEMENT OF MYCOTIC-ANEURYSM FOLLOWING REPAIR OF CORRECTED TRANSPOSITION JOURNAL OF CARDIAC SURGERY SUBIN, K., Mainwaring, R. D., Lamberti, J. J., Carter, T. L., Billman, G. 1994; 9 (1): 55-60

  Abstract

  Omental flaps have been used for the treatment of infected aortic prosthetic grafts in adults. We report the case of a 26-month-old male who developed a mycotic aneurysm 9 months following insertion of a ventricle to pulmonary artery conduit. The aneurysm was excised and the reconstructed outflow tract wrapped with omentum. The patient has not had recurrence of his aneurysm following this course of management.

  View details for Web of Science ID A1994MU85600007

  View details for PubMedID 8148544

• MANAGEMENT OF SYSTEMIC ATRIOVENTRICULAR VALVE REGURGITATION IN INFANTS AND CHILDREN JOURNAL OF CARDIAC SURGERY Lamberti, J. J., Mainwaring, R. D., George, L., Oury, J. H. 1993; 8 (6): 612-621

  Abstract

  Since September 1979, 53 patients have required operation for systemic atrioventricular valve regurgitation at Children's Hospital and Health Center of San Diego. (Primary repairs of atrioventricular canal defects are excluded from this report.) Diagnoses include single ventricle, cardiomyopathy, congenital mitral insufficiency , Marfan's disease, rheumatic heart disease, and a history of prior repair of atrioventricular canal defect. Ages ranged from 4 months to 19 years; median age is 5 years. In 31 patients, the atrioventricular valve could be repaired. In 24 patients, the valve was replaced (including two patients previously repaired). There were four operative deaths, all in the valve replacement group: three following valve replacement, and one following emergency thrombectomy. Two early failures in the repair group required valve replacement. Techniques for repair included leaflet resection, commissural annuloplasty, ring annuloplasty, and chordal shortening. Follow-up reveals good-to-excellent status in 38 patients. There were seven late deaths: six following valve replacement (one death valve related). Current surgical technique permits repair of the systemic atrioventricular valve in many infants and children requiring operation for regurgitation. The long-term results of valve repair are good to excellent. Repair avoids the morbidity and mortality of valve replacement, e.g., anticoagulation, fixed orifice size, and catastrophic mechanical valve malfunction.

  View details for Web of Science ID A1993MJ30200001

  View details for PubMedID 8286865

• PULMONARY ATRESIA WITH INTACT VENTRICULAR SEPTUM - SURGICAL APPROACH BASED ON VENTRICULAR SIZE AND CORONARY ANATOMY JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Mainwaring, R. D., Lamberti, J. J. 1993; 106 (4): 733-738

  Abstract

  Pulmonary atresia with intact ventricular septum has continued to have a high surgical mortality. This may relate to the nonuniformity of the anomaly. We have developed a management algorithm based on the right ventricular size and coronary anatomy. Patients with a well-developed ventricle and normal coronary arteries have undergone right ventricular outflow procedures. The adequacy of their right ventricles is subsequently evaluated; some patients are candidates for a four-chamber repair, whereas others are candidates for a Fontan procedure. Patients with severe hypoplasia of the right ventricle frequently have extensive ventriculo-coronary connections, and for these patients we have developed the technique of right ventricular obliteration. Over the past 7 years, we have treated 20 patients with pulmonary atresia with intact ventricular septum. Fourteen of the 20 patients underwent outflow tract procedures, with no operative mortality. There were two late deaths in this group. Six patients had hypoplasia of the ventricle with ventriculo-coronary connections and underwent right ventricular obliteration. There was one operative death and one late death in the group. Overall, 95% survived the neonatal period, and 80% were still alive at the time this article was written with an average follow-up of 32 months. We conclude that pulmonary atresia with intact ventricular septum can be successfully managed with the use of an algorithm based on ventricular size and coronary anatomy.

  View details for Web of Science ID A1993MA73300022

  View details for PubMedID 8412270

• NECK CANNULATION FOR THE REPAIR OF THORACIC ARTERY ANEURYSMS IN THE INFANT JOURNAL OF CARDIAC SURGERY Mainwaring, R. D., Lamberti, J. J., Rohrer, C., WINKLER, M. 1993; 8 (5): 541-545

  Abstract

  Thoracic aneurysms are relatively rare in infancy. We report our experience with two such patients, one with a false aneurysm of the ascending aorta and the other with a mycotic aneurysm of the main pulmonary artery. Neck cannulation prior to sternotomy, using cannulae designed for extracorporeal membrane oxygenation, allowed entry into the mediastinum under controlled circumstances and permitted the successful repair of the aneurysms.

  View details for Web of Science ID A1993MC04500004

  View details for PubMedID 8219534

• MANAGEMENT OF ABSENT PULMONARY VALVE SYNDROME WITH PATENT DUCTUS-ARTERIOSUS JOURNAL OF CARDIAC SURGERY Mainwaring, R. D., Lamberti, J. J., Spicer, R. L. 1993; 8 (2): 148-155

  Abstract

  The etiology of absent pulmonary valve syndrome is unknown. Several theories have been advanced to explain the associated findings of a rudimentary pulmonary valve, ventricular septal defect, aneurysmal pulmonary arteries, and absence of the ductus arteriosus. The patient presented here would contradict these currently held theories. A review of the literature follows the case report.

  View details for Web of Science ID A1993KU10400007

  View details for PubMedID 8461497

• Bioprosthetic Valves in Children: Results. Heart Surgery. Lamberti JJ, and Mainwaring RD. 1993: 91-103
• Palliation of the Univentricular Heart. Heart Surgery. Lamberti JJ, Uzark K, Mainwaring RD, Spicer RL. 1993: 153-160
• OMENTAL TRANSFER FOR THE TREATMENT OF MEDIASTINITIS IN AN INFANT JOURNAL OF CARDIAC SURGERY Mainwaring, R. D., Lamberti, J. J., Kirkpatrick, S. E. 1992; 7 (3): 269-274

  Abstract

  Mediastinitis following congenital heart surgery is relatively uncommon but is usually seen in the setting of postoperative low cardiac output. Conservative treatment utilizing debridement and irrigation is associated with significant morbidity and mortality. We report the successful application of the omental transfer technique in the treatment of mediastinitis in a 6 month old.

  View details for Web of Science ID A1992JL05900011

  View details for PubMedID 1392236

• THE CARDIAC ILLNESS OF LEE,ROBERT,E. SURGERY GYNECOLOGY & OBSTETRICS Mainwaring, R. D., Tribble, C. G. 1992; 174 (3): 237-244

  Abstract

  We believe that General Robert E. Lee had ischemic heart disease. It is our opinion that he sustained a heart attack in 1863 and that this illness had a major influence on the battle of Gettysburg. Lee experienced relatively good health from 1864 to 1867, but by 1869 he had exertional angina and by the spring of 1870 had intermittent rest angina. Although his symptoms were typical of angina, his physicians consistently diagnosed pericarditis, which we believe was erroneous. This misdiagnosis can be explained by the lack of familiarity of American physicians with angina during the 19th Century. It often was stated that the loss of the war broke the heart of Lee, but in view of our modern day understanding, it probably is more accurate to say that advancing coronary atherosclerosis was the culprit.

  View details for Web of Science ID A1992HH21800015

  View details for PubMedID 1542842

• THE DAMUS-FONTAN PROCEDURE ANNALS OF THORACIC SURGERY Lamberti, J. J., Mainwaring, R. D., Waldman, J. D., George, L., Mathewson, J. W., Spicer, R. L., Kirkpatrick, S. E. 1991; 52 (3): 676-679

  Abstract

  The Damus-Kaye-Stansel operation is a useful technique for the treatment of complex cyanotic congenital heart disease when there is obstruction between the systemic ventricle and the aorta. Modifications of the technique include transection of the aorta and the pulmonary artery, anastomosis of the contiguous aortic and pulmonary walls, and connection of the distal aorta to the perimeter of the new bivalved proximal great artery. In addition, the bidirectional cavopulmonary shunt technique can be used with or without the Fontan procedure. Six patients underwent a Damus-Fontan operation, and all survived. Two patients underwent the Damus-cavopulmonary shunt (hemi-Fontan) procedure, and 1 survived. The postoperative status of the 7 survivors is good to excellent. Follow-up ranges from 2 months to 7 1/2 years.

  View details for Web of Science ID A1991GG67900060

  View details for PubMedID 1898172

• THE INUTERO LEFT-VENTRICLE OF THE FETAL SHEEP - THE EFFECTS OF ISOPRENALINE JOURNAL OF PHYSIOLOGY-LONDON Anderson, P. A., FAIR, E. C., KILLAM, A. P., Nassar, R., Mainwaring, R. D., Rosemond, R. L., WHYTE, L. M. 1990; 430: 441-452

  Abstract

  1. Isoprenaline was infused into in utero fetal lambs to examine the effect of this beta-adrenoceptor agonist on left ventricular stroke volume and left ventricular output and test the generally held assumption that the fetal ventricle is markedly limited in its ability to increase ventricular output. 2. Seven in utero lambs (121-133 days of gestation) were instrumented with left ventricular dimension transducers, an ascending aortic electromagnetic flow transducer, a brachiocephalic arterial catheter and electrocardiographic and atrial pacing electrodes. 3. On the day of study, 5-8 days following surgery and 129-137 days of gestation, each lamb received infusions of isoprenaline, via the superior vena cava or left atrium, at rates which ranged from 0.005-0.5 microgram kg-1 min-1. 4. Heart rate and left ventricular stroke volume, output and end-diastolic and end-systolic dimensions were measured under control conditions and during various levels of isoprenaline infusion, with and without controlling heart rate. 5. Analysis of variance was done using the mean cell model. Least-square means and standard errors of the least-square means are reported. F ratios were calculated from type III sums-of-squares; P less than 0.05 was considered significant. 6. The mean heart rate increased with isoprenaline (P less than 0.0001) from a mean control level of 169 +/- 8 to 281 +/- 9 beats min-1 (+/- S.E.M.). 7. Mean left ventricular end-diastolic and end-systolic minor axis dimensions decreased significantly with isoprenaline from 16.7 +/- 0.1 mm (control) to 15.7 +/- 0.2 mm (P less than 0.0004) and from 11.7 +/- 0.1 mm (control) to 10.4 +/- 0.2 mm (P less than 0.0001) respectively. When heart rate was controlled with atrial pacing, mean end-diastolic dimension increased significantly at the higher isoprenaline doses from 14.6 +/- 0.1 mm (control) to 15.3 +/- 0.2 mm (control) (P = 0.0002), while mean end-systolic dimension fell significantly from 10.9 +/- 0.1 to 10.5 +/- 0.1 mm (P less than 0.003). Inasmuch as stroke volume increased, the increase in end-diastolic dimension and the fall in end-systolic dimension indicate an increase in venous return to the left ventricle. 8. During spontaneous rhythm, isoprenaline increased stroke volume from 2.45 +/- 0.06 ml (control) to 2.63 +/- 0.09 ml, not statistically significant. When heart rate was controlled, stroke volume increased with isoprenaline dose from 1.68 +/- 0.06 ml (control) to 2.40 +/- 0.08 ml (P less than 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)

  View details for Web of Science ID A1990EH23500024

  View details for PubMedID 2086769

• SYNCHRONOUS HEPATOCELLULAR-CARCINOMA AND ADENOCARCINOMA OF THE COLON AMERICAN SURGEON Mainwaring, R. D., Rivera, J., Wilson, W. 1989; 55 (8): 528-532

  Abstract

  It is not uncommon for patients with colon cancer to have a second primary neoplasm. The reported incidence of synchronous colon tumors is approximately about 3 to 4 per cent. Colon cancer also may be associated with a synchronous extra-colonic neoplasm; this incidence is less well defined and certainly is less emphasized in the literature. The authors recently treated a patient who had a synchronous hepatoma and adenocarcinoma of the colon. This appears to be the first report of these tumors presenting synchronously. The patient had both tumors resected and has no evidence of recurrence ten months later. This case illustrates the need to seek both colonic and extra-colonic synchronous tumors in patients discovered to have a colon cancer.

  View details for Web of Science ID A1989AK75200014

  View details for PubMedID 2548428

• PURINE-ENRICHED ASANGUINEOUS CARDIOPLEGIA RETARDS ADENOSINE-TRIPHOSPHATE DEGRADATION DURING ISCHEMIA AND IMPROVES POSTISCHEMIC VENTRICULAR-FUNCTION JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY Wyatt, D. A., Ely, S. W., Lasley, R. D., Walsh, R., Mainwaring, R., Berne, R. M., MENTZER, R. M. 1989; 97 (5): 771-778

  Abstract

  Myocardial dysfunction after induced ischemic arrest is an important problem in cardiac surgery. Adenosine-5'-triphosphate content in myocardial tissue remains depressed for days after ischemia, perhaps because of reperfusion washout of diffusable purine substrates. Left ventricular function is also depressed after ischemia, but its relationship to absolute tissue adenosine triphosphate content is unclear. We tested the hypothesis that arresting hearts with a cardioplegic solution containing adenosine, hypoxanthine, and ribose would result in improved tissue adenosine triphosphate content and left ventricular function after 1 hour of normothermic global ischemia in dogs supported by cardiopulmonary bypass. Animals with ischemic arrest initiated with a crystalloid cardioplegic solution containing adenosine 100 mumol/L, hypoxanthine 100 mumol/L, and ribose 2 mmol/L demonstrated significant improvement (p less than 0.05) during postischemic reperfusion. A significant correlation (p less than 0.05) existed between myocardial adenosine triphosphate content and the recovery of left ventricular function. These experiments demonstrate that an asanguineous cardioplegic solution containing adenosine, hypoxanthine, and ribose maintains myocardial adenosine triphosphate content during ischemia and reperfusion and enhances functional recovery during the postischemic period.

  View details for Web of Science ID A1989U452900015

  View details for PubMedID 2496276

• DIFFERENTIATING PANCREATIC PSEUDOCYST AND PANCREATIC NECROSIS USING COMPUTERIZED-TOMOGRAPHY ANNALS OF SURGERY Mainwaring, R., Kern, J., Schenk, W. G., RUDOLF, L. E. 1989; 209 (5): 562-568

  Abstract

  Ten per cent of patients with acute pancreatitis will develop pancreatic complications. Differentiating pancreatic pseudocyst formation from pancreatic necrosis may be difficult based on clinical grounds. The purpose of this study was to evaluate the role of computerized tomography in differentiating these processes. A retrospective analysis was performed of 40 patients who developed pancreatic complications following an episode of acute pancreatitis and who subsequently underwent operation for drainage of their pancreatic fluid collections. All 40 patients had abdominal CT scans performed before surgery and the patients were then categorized on the basis of CT findings as having (1) a pseudocyst with a well-defined cyst wall, (2) peripancreatic fluid marked by the absence of a cyst wall, and (3) a combination of a pseudocyst as well as free peripancreatic fluid. Patients with pseudocysts had an average hospital stay of 14 +/- 2 days, a hospital morbidity rate of 16%, and a hospital mortality rate of 0%. In contrast, patients with peripancreatic fluid collections had an average hospital stay of 43 +/- 4 days (p less than 0.01) and hospital morbidity and mortality rates of 74% (p less than 0.01) and 22% (p less than 0.05), respectively. Patients with both pseudocysts and peripancreatic fluid collections behaved in a similar fashion to patients with peripancreatic fluid alone as characterized by a prolonged hospital stay and a high incidence (80%) of postoperative complications. At one year follow-up, 89% of the patients with pseudocysts were asymptomatic, whereas only 13% (p less than 0.01) of patients with peripancreatic fluid were symptom free. These data demonstrate that pseudocyst and peripancreatic fluid collections have markedly different biologic characteristics both in their short-term and long-term behavior. The results suggest that CT scanning can differentiate these processes and may help in directing the appropriate surgical therapy.

  View details for Web of Science ID A1989U370700008

  View details for PubMedID 2705821

• The cryopreserved homograft valve in the pulmonary position: early results and technical considerations. Journal of cardiac surgery Lamberti, J. J., Angell, W. W., Waldman, J. D., GREHL, T. M., George, L., Mathewson, J. W., Kirkpatrick, S. E., Spicer, R., Thomson, D. 1988; 3 (3): 247-251

  Abstract

  Since September, 1985, 20 patients have undergone implantation of a homograft valve in the pulmonary position (16 pulmonary, 4 aortic). There were 11 primary operations and 9 reoperations. In 7 of 11 primary operations the homograft valve was utilized as a composite conduit with a short Dacron extension. In four of five reoperations for a failed porcine valved conduit, a composite homograft conduit was used. Four patients underwent implantation of a free homograft in a previously repaired right ventricular outflow tract (RVOT). Age ranged from 15 days to 22 years. There was one operative death (5%), a seven-week-old infant with truncus arteriosus. Long-term follow-up ranges from 1 to 30 months. Clinical performance has been satisfactory in 18 of 19 patients. One patient undergoing free implantation of a pulmonary valve in the RVOT required replacement at 18 months with a porcine valve. In this patient, pulmonary insufficiency was caused by distortion of the annulus secondary to dilatation and pulmonary hypertension. Nine of 18 survivors do not require medication. Eleven of 18 have trivial to mild pulmonary insufficiency murmurs without symptomatology. The homograft valve is extremely useful in reconstruction of the right heart, however, early insufficiency murmurs have been noted. Distortion of the valve annulus may contribute to the early onset of a benign insufficiency murmur. Residual distal obstruction or pulmonary hypertension may be a contraindication to the use of a free homograft in the orthotopic position.

  View details for PubMedID 2980024

• MYOCARDIAL REACTIVE HYPEREMIA IN THE NEWBORN JOURNAL OF SURGICAL RESEARCH Mainwaring, R. D., Ely, S. W., MENTZER, R. M. 1988; 44 (5): 603-608

  Abstract

  Adenosine may be an important metabolic regulator of coronary blood flow during active hyperemia in the newborn. In this study, the adenosine uptake blocker dipyridamole (DPY) and receptor antagonist theophylline (THEO) were used to assess the role of adenosine in the reactive hyperemic response of the neonatal heart. Eighteen anesthetized, open-chest lambs were instrumented with aortic and coronary sinus catheters as well as an extracorporeal shunt to the circumflex coronary artery incorporating a 2.0-mm electromagnetic flow transducer. Ten-second occlusions of the circumflex coronary artery catheter were performed, and the resulting reactive hyperemia was used to determine peak hyperemic blood flow (PHF), duration of hyperemia, and the blood flow repayment. These values were determined prior to treatment and 30 min following administration of a saline vehicle, DPY (0.2 mg/kg) or THEO (5 mg/kg). DPY resulted in increases in PHF from 220 +/- 12 to 247 +/- 14 ml/min/100 g heart tissue (P less than 0.05), durations of hyperemia from 29 +/- 2 to 38 +/- 2 sec (P less than 0.01), and blood flow repayments from 65 +/- 2 to 102 +/- 4 ml/100 g (P less than 0.001). THEO resulted in decreases in PHF from 224 +/- 15 to 198 +/- 12 ml/min/100 g (P less than 0.05), durations of hyperemia from 28 +/- 2 to 22 +/- 2 sec (P less than 0.05), and blood flow repayments from 64 +/- 2 to 46 +/- 2 ml/100 g (P less than 0.01). The data indicate that DPY enhances reactive hyperemia while antagonism of adenosine with THEO attenuates it. These results suggest that adenosine plays a role in mediating reactive hyperemia in the newborn heart.

  View details for Web of Science ID A1988N642000019

  View details for PubMedID 3374124

• ADENOSINE STIMULATES GLUCOSE-UPTAKE IN THE ISOLATED RAT-HEART SURGERY Mainwaring, R., Lasley, R., Rubio, R., Wyatt, D. A., MENTZER, R. M. 1988; 103 (4): 445-449

  Abstract

  Adenosine (Ado) is a potent coronary vasodilator. Recent studies suggest that Ado may also have an important effect on myocardial carbohydrate metabolism. To determine whether Ado has a direct effect on myocardial glucose uptake, a recirculating, constant-flow, isolated rat-heart preparation was used. The hearts were perfused with Krebs-Henseleit buffer solution with an initial glucose concentration of 11 mmol/L. A control group was compared with hearts treated with Ado infusions (50 and 100 micrograms/min) or insulin (100, 200, and 300 microU/ml). In a separate series of experiments, nitroprusside was used to evaluate the effect of a nonspecific coronary vasodilator. The rate of glucose uptake was calculated as the amount of glucose removed from the perfusate normalized for heart weight and time. Developed pressure (DP) was assessed with an intraventricular balloon, and the coronary perfusion pressure (CPP) was monitored. At the end of 1 hour, the hearts were freeze-clamped and adenine nucleotide content was measured with HPLC. Ado treatment increased glucose uptake by 80% and 140%, respectively, at the two infusion rates (p less than 0.001). Myocardial adenosine triphosphate content was 18% and 26% higher in the Ado-treated hearts than in the controls (p less than 0.001). Ado also decreased the mean DP by 30% and 36% (p less than 0.001) and decreased CPP by 10% and 22%, respectively (p less than 0.001). Insulin increased glucose uptake in a similar dose response fashion but had no effect on myocardial nucleotide content, DP, or CPP. Nitroprusside decreased CPP but had no effect on glucose uptake, adenine nucleotide content, or DP. These results suggest that Ado may have a direct effect on glucose uptake independent of its properties as a coronary vasodilator.

  View details for Web of Science ID A1988M843600010

  View details for PubMedID 3281300

• AGGRESSIVE ANGIOMYXOMA WITH GASTROINTESTINAL COMMUNICATION - A CASE-REPORT CT-JOURNAL OF COMPUTED TOMOGRAPHY TATU, W. F., Holmes, W. S., Black, W. C., Mainwaring, R., Carter, T. 1988; 12 (1): 32-35

  Abstract

  We report the imaging findings of an abdominal aggressive angiomyxoma, which communicated with the gastrointestinal tract. The literature on this rare tumor is reviewed.

  View details for Web of Science ID A1988M102400007

  View details for PubMedID 3349796

• INUTERO RIGHT VENTRICULAR OUTPUT IN THE FETAL LAMB - THE EFFECT OF HEART-RATE JOURNAL OF PHYSIOLOGY-LONDON Anderson, P. A., KILLAM, A. P., Mainwaring, R. D., Oakeley, A. E. 1987; 387: 297-316

  Abstract

  1. The effect of heart rate on right ventricular output was examined in six lambs during a period extending from 126 to 139 days of gestation. The fetuses had been surgically instrumented at least four days previously with a main pulmonary artery flow probe, right ventricular dimension transducers and left and right atrial pacing electrodes. 2. During spontaneous variations in heart rate, rate was correlated positively with right ventricular output (P less than 0.0001) and end-diastolic dimension (P less than 0.0001) among the lambs considered as a group, but no significant effect of rate on stroke volume was found. When individual responses were examined, output increased significantly with rate in sixteen out of seventeen observations. 3. With left atrial pacing, heart rate did not affect output. With right atrial pacing, rate correlated negatively with output (P less than 0.0001). With pacing from either site, rate correlated negatively with end-diastolic dimension (P less than 0.0001) and stroke volume (P less than 0.0001). 4. The introduction of a longer period interval during each pacing rate inhibited the rate-related decrease in dimension and allowed the ventricle to fill to the same end-diastolic dimension. The systole following these longer intervals had a greater stroke volume than did the preceding systoles with smaller end-diastolic dimension. The faster the preceding paced rate, the greater was the increase in stroke volume (P less than 0.001). 5. Right ventricular dimensions and volumes were measured in vitro, and the relationship was found to be linear using regression analysis. 6. This study demonstrates that experimentally induced variations in heart rate produce changes in end-diastolic volume and contractility which prominently affect right ventricular stroke volume. As a consequence, rate has, over a broad range, either no significant effect on output or a negative one. With spontaneous variations in rate, additional changes in contractility and venous return occur which affect stroke volume and end-diastolic volume and enhance right ventricular output. These relationships are similar to those in the adult heart, and demonstrate the absence of a maturational change in the effects of rate on ventricular function from the fetus to the adult.

  View details for Web of Science ID A1987H570000017

  View details for PubMedID 3656174

• EFFECTS OF DIPYRIDAMOLE ON MYOCARDIAL GLUCOSE-UPTAKE IN THE NEWBORN LAMB JOURNAL OF SURGICAL RESEARCH Mainwaring, R. D., MENTZER, R. M. 1986; 40 (6): 528-533

  Abstract

  Carbohydrates are an important source of energy for the immature myocardium. Since dipyridamole (DPY) has been reported to facilitate glucose uptake in the adult heart, the present study was designed to determine whether DPY could enhance glucose uptake in the nonischemic newborn. In anesthetized, open chest lambs (n = 8), circumflex coronary blood flow (CBF), myocardial adenine nucleotide content, and aortic and coronary sinus concentrations of glucose, lactate, and pyruvate were determined before and after a single dose of DPY (0.2 mg/kg, intravenously). Adenine nucleotides were measured by HPLC. The consumption of substrates was calculated as the product of CBF and the aortic-coronary sinus difference in substrate concentration. Coronary blood flow averaged 114 +/- 6 ml/min/100 g in the untreated animals, and increased by 44% following treatment with dipyridamole (P less than 0.01). This was associated with a 32% decrease in coronary vascular resistance (P less than 0.01). Glucose uptake increased from 9 to 46 mumoles/min/100 g (P less than 0.01) following dipyridamole treatment; lactate uptake decreased by 97% (P less than 0.01). There was a net release of pyruvate from the neonatal hearts; this increased from 18 to 25 mumole/min/100 g (P less than 0.05). Myocardial ATP content averaged 4.08 mumole/g wet wt in the untreated animals, and increased 11% to 4.52 following DPY (P less than 0.01). The agent had no effect on the myocardial tissue levels of AMP or ADP. These data indicate that DPY is a coronary vasodilator in the newborn lamb and augments both glucose uptake and myocardial ATP content. These metabolic effects provide a rationale for further studies during periods of hypoxia and ischemia.

  View details for Web of Science ID A1986E073200002

  View details for PubMedID 3747488

• THE EFFECT OF HEART-RATE ON INUTERO LEFT-VENTRICULAR OUTPUT IN THE FETAL SHEEP JOURNAL OF PHYSIOLOGY-LONDON Anderson, P. A., GLICK, K. L., KILLAM, A. P., Mainwaring, R. D. 1986; 372: 557-573

  Abstract

  The effect of heart rate on left ventricular output was examined in seven fetal lambs at ages of 128 to 140 gestational days. The fetuses had been surgically instrumented at least 4 days previously with an ascending aortic flow probe, left ventricular dimension transducers, and left and right atrial pacing electrodes. Natural variations in heart rate of the lambs taken as a group correlated positively with left ventricular output, and negatively with ventricular end-diastolic dimension and stroke volume (P less than 0.0001). Rate did not affect output with right atrial pacing. With left atrial pacing, it correlated negatively with output (P less than 0.0001). At both pacing sites, rate correlated negatively with end-diastolic dimension and stroke volume (P less than 0.0001). The introduction of a longer interval during each pacing rate circumvented the rate-related changes in dimension and allowed the ventricle to fill to the same end-diastolic dimension. The systole at the end of the longer interval had a greater stroke volume than the preceding systoles. The faster the preceding paced rate, the greater was the stroke volume (P less than 0.0001). This study demonstrates that experimentally induced variations in heart rate produce changes in end-diastolic volume and contractility which prominently affect stroke volume. Over a broad range of rates, however, the effect of rate on left ventricular output is either negative or absent. With naturally occurring rate changes, there are additional changes in contractility and venous return which affect stroke volume. These combine to produce a positive relation between heart rate and left ventricular output. These effects of heart rate on output are qualitatively similar to those described for the adult animal.

  View details for Web of Science ID A1986A551000033

  View details for PubMedID 3723419

• HORMONAL ROLE OF ADENOSINE IN MAINTAINING PATENCY OF THE DUCTUS-ARTERIOSUS IN FETAL LAMBS ANNALS OF SURGERY MENTZER, R. M., Ely, S. W., Lasley, R. D., Mainwaring, R. D., Wright, E. M., Berne, R. M. 1985; 202 (2): 223-230

  Abstract

  The hypothesis that endogenously released adenosine plays an important role in maintaining patency of the fetal lamb ductus arteriosus was tested. The design of the study was (1) to determine the effect, if any, of exogenous adenosine on blood flow through the ductus arteriosus and (2) to evaluate the relationship among the partial pressure of oxygen in arterial blood, circulating endogenous plasma adenosine concentration, and the rate of blood flow through the ductus. When exogenous adenosine (5 mumoles) was administered during oxygen-induced ductal constriction, ductal blood flow increased from 101 +/- 6 ml/min to 153 +/- 4 ml/min (p less than 0.01). When fetal blood adenosine concentrations were measured during nonventilation and ventilation with 100% oxygen, endogenous adenosine concentrations fell to less than one-half of the preventilation levels, i.e., from 1.12 +/- 0.17 to 0.49 +/- 0.03 microM (p less than 0.01). Finally, when fetal lambs were ventilated with increasing concentrations of oxygen (0%, 10%, 20%, 60%, and 100%) and measurements obtained simultaneously at each level, there was a significant monoexponential relationship among the rise in PO2, the fall in plasma adenosine concentration, and the decrease in ductal blood flow. These data suggest that: (1) adenosine is a potent vasodilator of the lamb ductus arteriosus during oxygen-induced vasoconstriction; (2) fetal endogenous plasma adenosine levels fall significantly when PO2 is increased; and (3) the fall in adenosine concentrations parallels a decrease in ductal blood flow. The findings suggest that the endogenous vasodilator adenosine plays an important role in maintaining ductal patency in utero.

  View details for Web of Science ID A1985AMX7000013

  View details for PubMedID 4015227

• THE ROLE OF ADENOSINE IN THE REGULATION OF CORONARY BLOOD-FLOW IN NEWBORN LAMBS SURGERY Mainwaring, R. D., MENTZER, R. M., Ely, S. W., Rubio, R., Berne, R. M. 1985; 98 (3): 540-546

  Abstract

  Adenosine is a metabolic vasodilator of the coronary vessels in the adult. Whether it plays a similar role in the regulation of coronary blood flow (CBF) in the newborn is not known. We evaluated changes in adenosine release during periods of decreased oxygen supply (hypoxia) and increased oxygen demand (dobutamine infusions). In anesthetized open-chest lambs (age 1 to 8 days), aortic and coronary sinus adenosine concentrations, circumflex CBF, and myocardial oxygen consumption (MVO2) were measured. Adenosine was assayed by high-performance liquid chromatography, and the release of adenosine was calculated as the product of the aortic-coronary sinus plasma level difference and CBF in milliliters per minute per 100 gm myocardial tissue. Control values were obtained when the lambs were ventilated with 60% oxygen. In the first series of experiments, hypoxemia resulted in an increase in CBF from 120 +/- 5 to 171 +/- 8 ml/min/100 gm (p less than 0.01). This was associated with sixfold increase in adenosine release. In a second set of experiments the intravenous infusion of dobutamine resulted in parallel increases in MVO2 and CBF. Concomitantly, adenosine release increased by fivefold. There were significant linear relationships between MVO2 and CBF (r = 0.96; p less than 0.01), MVO2 and adenosine release (r = 0.69; p less than 0.002), and adenosine release and CBF (r = 0.71; p less than 0.002). These data support the hypothesis that adenosine may play an important role in the regulation of CBF in the newborn lamb.

  View details for Web of Science ID A1985AQH1400022

  View details for PubMedID 4035574