Heparin treatment of deep venous thrombosis in 280 patients: symptoms related to dosage.

280 patients with phlebographically proven deep venous thrombosis received intravenous heparin infusion, mean duration 6.8 days, mean dose 370 U/kg/day. In 58 patients (21%) there was no apparent predisposing factor. Leg pain diminished more rapidly than edema. At discharge, 46% had edema. Symptoms suggesting pulmonary embolism (PE) occurred in 13 patients (4.6%) whose mean daily heparin dose was similar to that of the others. The only fatal PE occurred three days after cessation of heparin administration. Eight patients (3%) experienced major bleeding, the only fatal occurring after thoracocentesis. The frequency of major bleeding in patients above 70 years was 8% in females and 4% in males, in those below 70 years it was 0.5%; 22 patients (8%) had minor bleeding. Control phlebography after one week revealed completely cleared thrombus in 3%, partial clearance in 36%, unchanged in 39% and increased thrombosis in 22%. Dosage was significantly correlated to thrombus resolution.