Prevention of postoperative thromboembolism with Enoxaparin in general surgery: a German multicenter trial

The antithromboembolic efficacy and safety of Enoxaparin, a low molecular weight heparin preparation, has been studied in a multicenter prospective randomized trial in 10,032 patients scheduled for a variety of elective general surgical, gynecologic, and urologic procedures. There were 9919 patients operated on and who received Enoxaparin, of whom 9907 patients were randomized into two groups. The morning group, composed of 4987 patients, received a subcutaneous injection of 20 mg Enoxaparin 2 hours before surgery and each morning for 7 postoperative days. The evening group, composed of 4920 patients, received the identical injection the evening before surgery and postsurgically for 7 days in the evening. Both groups were comparable in age, gender, weight, surgical category, anesthesia, and any risk factors that could predispose to the development of DVT or PE. The objective of this study was to detect efficacy and safety of Enoxaparin 20 mg under typical clinical conditions. The results were the following: PE was reported in 24 patients, leading to an incidence of PE under Enoxaparin prophylaxis of 0.24% in total, 0.21% for nonfatal and 0.03% for fatal PE. There were no differences in the incidence between the morning and evening groups. The incidence of DVT diagnosed by clinical signs was found to be 0.11%, with six cases in the morning group and five cases in the evening group. An analysis of operative and postoperative bleeding showed no difference between the groups in terms of blood transfusion requirements and drainage volumes, excessive bleeding in the wound area, or other bleeding complications. There was a slight postoperative decrease in haemoglobin and hematocrit in both groups. However, no severe Enoxaparin-induced thrombocytopenia was observed. Only 71 patients (0.72%) reported adverse drug reactions, most of which were local reactions. The results from this study indicate that a single daily injection of 20 mg Enoxaparin is a safe and efficient prophylaxis for thromboembolic complications in patients undergoing any of a variety of general surgical procedures. This study indicates that prevention of thromboembolism is not strictly limited to a 2-hour interval between start of prophylaxis and onset of surgery but may also be provided by starting prophylaxis with 20 mg Enoxaparin during the evening before surgery and continuing treatment postoperatively.