An iatrogenic AV fistula is best described as a communication between which vessels?

• A. Artery and adjacent vein
• B. Vein and lymphatic vessel
• C. Nerve and artery
• D. Artery and artery

Answer: (A)

An iatrogenic AV fistula is a direct abnormal connection between an artery and an adjacent vein. This occurs when a medical procedure injures both vessels, creating a channel that lets high-pressure arterial blood flow directly into the venous system. The resulting high-flow shunt can cause a palpable thrill and a bruit at the site, and in larger fistulas may lead to edema or increased cardiac workload due to the extra venous return. This description fits best because the hallmark is a communication between artery and vein, unlike a lymphatic-venous fistula (vein and lymphatic vessel), a neurovascular injury (nerve and artery), or an artery-to-artery connection, which do not describe an arteriovenous fistula. Diagnosis is typically with duplex ultrasound or angiography, and treatment aims to close the abnormal connection, often with endovascular repair or surgical intervention.