Lung AVMs (areteriovenous malformations) are the most common cause of severe and sudden harm to individuals with HHT. Most often lung AVMs do not cause harm by bleeding, but reduce the ability of the lungs to filter blood from clots or clumps of bacteria as it circulates through the body. This filtering of impurities of the blood after each trip around the body is an important function of the lungs. Because blood clots and clumps of bacteria are less likely to be filtered from the blood, individuals with AVMs in their lungs are more likely to have (clot type) strokes and brain abscess. These can be prevented if lung AVMs are detected and treated before they cause symptoms.
Treatment: Lung AVMs are treated by a non-surgical procedure called embolization. This procedure uses catheters to remove lung AVMs by blocking off their blood flow.
About one in 10 individuals with HHT have a brain AVM, and about half of these will result in a brain hemorrhage over a lifetime if not detected and treated. These hemorrhages usually occur without prior warning signs, and the consequence is often death or disability. Since the hemorrhages often take place very early in life, we recommend screening during a child’s first year.
Treatment: If detected, most brain AVMs can be safely treated by stereotactic radiosurgery, embolization, or surgery.
Although liver arteriovenous malformations are common in HHT, they almost never rupture and bleed as can telangiectasia and AVMs in most other locations. Treatment is rarely needed unless the heart is adversely affected by the resulting extra blood flow.
Treatment: When needed, treatment with an anti-angiogenesis drug is most common, since AVMs in the liver do not respond well to either surgery or embolization.