arteriovenous malformation
Also written as: AVM — arteriovenous malformation
An abnormal direct connection between arteries and veins bypassing the normal capillary bed, occurring as a congenital vascular anomaly.
Full Definition
Arteriovenous malformations (AVMs) are congenital vascular lesions characterized by direct arteriovenous communications without intervening capillaries. In the heart, they most commonly occur as coronary arteriovenous malformations or pulmonary AVMs. The abnormal connections create high-flow, low-resistance circuits that can lead to volume overload and congestive heart failure. Histologically, the feeding arteries show muscular hyperplasia and the draining veins demonstrate arterialization. Large lesions may present with continuous murmurs and can be associated with paradoxical embolization.
Usage
Usage note: Distinguish from acquired arteriovenous fistulas.
In Context
- "The coronary angiography revealed a large arteriovenous malformation between the left anterior descending artery and coronary sinus." — catheterization report
- "Surgical resection of the pulmonary arteriovenous malformation showed typical histological features with arterialized veins." — surgical pathology report