Mechanical versus pharmacologic prevention of deep venous thrombosis.

The prevention postoperatively of deep venous thrombosis was studied using three different regimens in 227 patients undergoing surgical procedures. Seventy-six patients received 5,000 units of heparin subcutaneously and 0.5 milligrams of dihydroergotamine twice a day. In 76 patients, intermittent pneumatic compression of the legs was applied preoperatively and postoperatively with active physiotherapy. The last 75 patients received subcutaneously 5,000 units of heparin each eight hours. Systematic deep venous thrombosis detection was carried out using both the 125I fibrinogen test and the Doppler method, being confirmed by phlebography if positive. The 125I fibrinogen test proved to be more sensitive and more specific. The incidence of deep venous thrombosis and pulmonary embolism were comparable in the groups, mechanical prophylaxis being as effective as the two other regimens. No side-effects were noted with the use of intermittent compression boots. A venoconstricting agent associated with heparin may permit smaller doses with the same prophylactic effect.