arteriovenous malformation
Congenital vascular lesion with abnormal direct connections between arteries and veins.
Full Definition
An arteriovenous malformation (AVM) is a congenital vascular anomaly characterized by abnormal direct connections between arteries and veins, bypassing the normal capillary bed through a complex network of abnormal vessels called the nidus. AVMs can occur anywhere in the body but are most clinically significant when located in the brain, lungs, or other vital organs. The absence of a capillary bed results in high-flow, low-resistance shunting that can lead to progressive enlargement, steal phenomenon affecting adjacent normal tissue, and risk of hemorrhage. Cerebral AVMs are graded using the Spetzler-Martin scale based on size, location, and venous drainage pattern. Treatment options include surgical resection, endovascular embolization, stereotactic radiosurgery, or multimodal approaches depending on the AVM characteristics and patient factors.
Usage
Usage note: Often abbreviated as AVM after first use
In Context
- "The patient presented with seizures secondary to a left temporal arteriovenous malformation." — Neurology consultation note
- "Preoperative embolization was performed to reduce the arteriovenous malformation nidus before surgical resection." — Neurosurgical procedure report