Complications of heparin-induced thrombocytopenia.

Four cases are presented which are believed to represent thrombocytopenia associated with intravascular thrombosis and vascular occlusion in patients receiving heparin. Patients with gangrene all had pre-existing arterial disease and arterial insufficiency. Such venous and arterial thromboses are paradoxic and unpredictable and are completely against the goal of therapy. These complications may have been prevented if the developing thrombocytopenia was discovered earlier and heparin discontinued. Three of these patients died as a result of their complications, and one had an amputation. The unpredictable pattern of such paradoxic reactions requires close monitoring of the platelet count as well as activated PTT and prothrombin time.