Which type of blood vessel malformation is characterized by a direct connection between arterioles and venules?

The type of blood vessel malformation characterized by a direct connection between arterioles and venules is known as an arteriovenous malformation (AVM). An AVM creates a shunt that allows blood to flow directly from arteries to veins without passing through the capillary system. This direct connection can lead to a number of complications, including increased blood flow to the venous structures and potential dilation or rupture, which can be life-threatening.

In the context of vascular pathology, an AVM is a specific type of abnormality that can occur in various tissues and organs, often presenting with symptoms such as pain, swelling, or even neurological deficits if located in the brain. The unique feature of an AVM is the lack of an intermediate capillary network, which distinguishes it from other vascular issues. Understanding the implications of such malformations is crucial in the field of interventional radiology, where proper diagnosis and management can significantly impact patient outcomes.