Prophylaxis of Postoperative Deep Venous Thrombosis

To the Editor.—  The results of a multicenter trial of dihydroergotamine-heparin in the prophylaxis of postoperative deep vein thrombosis¹ concluded that a combination of dihydroergotamine mesylate, 0.5 mg, and heparin sodium, 5,000 IU, given subcutaneously twice daily, is superior to low-dose heparin alone. The criterion for deep vein thrombosis was a positive radiofibrinogen uptake test (RFUT) finding. We have reported the results of a randomized trial, based on 181 patients who underwent major abdominal surgery, comparing dihydroergotamine-heparin v heparin as prophylaxis for deep vein thrombosis.² We employed the RFUT as a screening procedure. Patients with a positive RFUT finding were subjected to ascending phlebography. The criterion for deep vein thrombosis was an abnormal phlebogram. There were two false-positive results for RFUTs in the patient group receiving dihydroergotamine-heparin and 11 false-positive results in the group given heparin only. Abnormal results of the RFUT were significantly more frequent in the heparin