Dihydroergotamine-Heparin Prophylaxis of Postoperative Deep Vein Thrombosis

To the Editor.—  The recent multicenter report on prophylaxis of postoperative thrombosis¹ and the editorial by Dr Hirsh² were excellent. Postoperative deep vein thrombosis (DVT), with the pulmonary embolism that so frequently follows it, continues to be one of the commonest causes of in-hospital deaths in this country. Considering its frequent occurrence, it is rather shocking how seldom appropriate prophylactic measures are being used in routine surgical practice.This study demonstrated quite clearly that dihydroergotamine with heparin, 5,000 IU, was more effective than the same dose of dihydroergotamine with 2,500 IU of heparin and, likewise, more effective than dihydroergotamine alone or 5,000 IU of heparin alone.This raises the question again as to whether the appropriate dose of heparin should not be chosen on the basis of the patient's probable sensitivity. As pointed out by Dr Hirsh,² the recent study of Leyvraz et al³ demonstrates that