Haemorrhagic complications of heparin therapy.

In a prospective trial 76 patients with venous thromboembolism have received intermittent constant-dosage heparin or continuously infused heparin with laboratory control. Frequencies of bleeding were similar in both groups. 32% of all patients bled, 13% severely. Retroperitoneal haemorrhage occurred in 5 patients. Major spontaneous bleeding was commoner in older patients and minor spontaneous bleeding in women. Bleeding was uncommon during the first 2 days of treatment, and its daily frequency was relatively constant thereafter. 21% of surgical wounds and 7% of arterial and venous puncture sites bled. These preliminary results illustrate the hazards of heparin therapy and suggest that bleeding complications are more closely related to duration of therapy, age, sex, and surgical trauma than to method of administration.