[Fatal central pulmonary embolism under heparin therapy: white-clot syndrome].

A 75-year old female underwent coronary angiography for chest pain. Significant proximal stenosis of the left coronary artery was found. During the waiting time for bypass surgery, intravenous heparin treatment was established for several days because of recurrent unstable angina pectoris. 10 days after coronary angiography an acute event with chest pain, hypotension, tachycardia and a new right bundle branch block suspect for myocardial infarction occurred, which was treated with rt-PA. Fever, persistent hypotension, acute progressive renal failure and thrombocytopenia suggested septic shock, and the patient was transferred to our hospital. A pulmonary artery catheter could not be advanced beyond the main stem of the pulmonary artery. The patient died suddenly 24 hours later from acute right ventricular failure. Autopsy demonstrated multiple white clots in both pulmonary arteries. The histological finding of clots rich in leukocytes and fibrin was compatible with the diagnosis of heparin-induced thrombosis-thrombocytopenia or white clot syndrome. Heparin-induced thrombocytopenia may occur after about 5 days of treatment. Two distinct types have been described. The first type occurs in up to 25% of patients receiving heparin and is a result of temporary platelet aggregation, margination and peripheral sequestration. The less common second type of thrombocytopenia is thought to be mediated by a heparin-dependent IgG antibody inducing platelet aggregation and may be associated with thromboembolic events leading to the white clot syndrome, which is rarely reported in the literature. In these cases heparin should be stopped immediately and replaced by oral anticoagulation. Other therapies such as low molecular weight heparin, synthetic heparinoids, hirudin, fibrinolytic agents, plasmapheresis and intravenous immunoglobulins are discussed. Monitoring of the platelet count every 5 days in patients receiving heparin for any extended period should become standard medical practice to avoid potential fatal complications.