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. Aneurysm and pseudoaneurysm formations may occur at the anastomotic sites, along the course of the graft or in the outflow veins. Pseudoaneurysms at anastomotic sites indicate dehiscence and require surgical repair.