arteriovenousyhteyden

An arteriovenous connection, often referred to as an arteriovenous fistula or shunt, is an abnormal link between an artery and a vein. Normally, arteries carry oxygenated blood away from the heart under high pressure, while veins carry deoxygenated blood back to the heart under lower pressure. An arteriovenous connection bypasses the capillary network, which is where the exchange of oxygen and nutrients occurs between the blood and tissues.

This direct connection causes blood to flow from the high-pressure arterial system directly into the lower-pressure venous system. This results in a number of physiological changes. The veins downstream of the connection become engorged and dilated due to the increased volume and pressure of blood flowing through them. The blood flowing through the connection itself is typically warmer than normal venous blood because it originates from an artery.

Arteriovenous connections can occur congenitally, meaning they are present from birth, or they can be acquired as a result of trauma, surgery, or certain medical procedures. When created intentionally for medical purposes, such as hemodialysis access, they are called arteriovenous fistulas. These surgically created connections are designed to provide large, robust blood vessels for efficient blood flow during dialysis treatments. Unintended or pathological arteriovenous connections can lead to a variety of symptoms, depending on their size and location, including swelling, pain, and, in severe cases, heart strain.