Acute occlusion of an abdominal aortic aneurysm--case report and review of the literature.

Acute thrombosis of an abdominal aortic aneurysm (AAA) is a surgical emergency. Only 44 cases have been reported in the literature. The mechanism of the thrombosis has not been delineated. The proposed etiologies include propagation of thrombus from distal artery occlusion, cardiac thromboembolism, and dislodgment of a mural thrombus. Patients often present bilateral lower extremity ischemia, mimicking a saddle embolism. Systemic heparinization immediately after diagnosis and prompt surgical revascularization can reduce the mortality rate. The authors present a patient with sudden thrombosis of an AAA who was successfully treated with an axillobifemoral bypass graft. All published cases of thrombosed AAAs are analyzed.