Acute mesenteric and aortic thrombosis associated with antithrombin deficiency: a rare occurrence.

Antithrombin is a potent inhibitor of the coagulation cascade exerting its primary effects on activated factors X, IX and II. It is the mechanism by which heparin and low-molecular weight heparin cause anti-coagulation. Deficiency of antithrombin presents as a hypercoagulable state, and may result in unexplained deep venous thrombosis, arterial thrombosis and systemic embolization.