Hereditary Hemorrhagic Telangiectasia (HHT)

Hereditary Hemorrhagic Telangiectasia (HHT)

Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder that affects about one in 5,000 people and causes arterial blood to flow directly into the veins, creating weakened ballooned vessels that can rupture. Interventional radiologists are one of the few specialists who can permanently treat this disease that affects approximately half a million people worldwide. As vascular experts, interventional radiologists perform embolization - blocking the blood flow to the affected area - to prevent a life-threatening rupture.

Most patients with HHT function normally and 40 percent have brain or lung involvement that may lead to unexpected severe complications. Physicians treating complications often don't realize that the underlying disorder is HHT. As a result, most patients are undiagnosed.

Overview of circulatory system and HHT

In the normal circulatory system, arteries take oxygenated blood from the heart and push it out to all parts of the body under high pressure, while the veins return the blood back to the heart. Small capillaries typically connect the arteries to the veins. A person with HHT lacks capillaries in a few blood vessels in critical locations. Arteries connect directly into veins, creating a fragile site that can rupture and bleed. These abnormal blood vessels are called telangiectasis if they involve small blood vessels (nose, stomach and small bowel) and arterioveneous malformations (AVM) if it involves a larger blood vessel (lung, brain and liver). Telangiectases often occur near the surface of the skin like the mucous membrane in the nose while AVMs appear in the internal organs of the body.