Shunting of arterial flow into the venous system will result in increased distal venous pressure and some evidence of edema may be present in the extremity. Arterial collateral vessels originate above the fistula and assist in perfusion distal to the fistula. May be the only source of blood flow to the distal extremity. If they contribute flow to the fistula via the distal artery, flow is reversed. May or may not be associated with sign and symptoms of ischemia.
Occlusion is the most common complication with all types of access grafts.
Early occlusion is usually caused by simple thrombosis. Late occlusions have a more complex etiology. Abrupt short segment occlusion is characteristic of graft thrombosis. With graft maturity and over time the artery becomes longer and more tortuous and may result in stenosis. Similar but much more prominent changes occur in the anastomotic vein.