EFFECT OF SMALL DOSES OF HEPARIN ON PLATELET ADHESIVENESS AND LIPOPROTEIN-LIPASE ACTIVITY BEFORE AND AFTER SURGERY

Although it is not certain that a reduction in platelet adhesiveness would affect the incidence of deep-vein thrombosis after surgery, a clinical trial of the smaller dose of heparin would seem worth while for, in respect of effect on coagulability, 1 I.U.Heparin per kg.

Abstract

In a group of male surgical patients platelet adhesiveness increased on the second postoperative day. 10 minutes after the intravenous injection of 10 I.U. heparin per kg. body-weight platelet adhesiveness had fallen significantly, but at 1 and 2 hours adhesiveness was back at preheparin levels. Lipoprotein-lipase activity rose 10 minutes after injection of heparin both preoperatively and postoperatively, but on the second postoperative day activity had returned towards preheparin levels 1 and 2 hours after the injection. When the platelet-adhesiveness experiments were repeated in a second group of patients given only 1 I.U. heparin per kg. body-weight, the response was similar to that observed with the higher dose, high postoperative platelet adhesiveness falling significantly 10 minutes after the administration of heparin. Although it is not certain that a reduction in platelet adhesiveness would affect the incidence of deep-vein thrombosis after surgery, a clinical trial of the smaller dose of heparin would seem worth while for, in respect of effect on coagulability, 1 I.U. per kg. heparin is truly a small dose.