Heparin induced thrombocytopenia: eight cases with thrombotic-hemorrhagic complications.

Increased heparin tolerance and recurrent thromboembolism which included myocardial infarction (3 patients), pulmonary embolism (2 patients) and complete aorto-iliac occlusion (2 patients), heralded the development of thrombocytopenia between the eighth and twelfth day of heparin therapy in six women and two men. The thrombocytopenia persisted until heparin was discontinued. Bleeding (cerebral hemorrhage) was the initial complication in one patients and occurred in conjunction with thrombotic complications in four other patients. Agglutination absorption testing in one and complement fixation testing in five patients suggested the presence of heparin dependent antiplatelet antibodies. After platelet recovery, four of the eight patients responded to parenteral heparin rechallenge with rapid decreases in their platelet counts. The early recognition of the syndrome with cessation of heparin therapy is imperative for the successful management of afflicted patients.