Low-molecular-weight heparin vs. unfractionated heparin in femorodistal reconstructive surgery: a multicenter open randomized study. Enoxart Study Group

Abstract

Several clinical trials have been conducted to study the role of low-molecular-weight heparin (LMWH) in the prevention and treatment of venous thrombosis. In contrast, there have been few studies investigating LMWH in the prophylaxis in arterial thrombosis. After informed consent and institutional approval were obtained, 201 consecutive patients scheduled for femorodistal reconstructive surgery under general anesthesia were enrolled in an open randomized multicenter (n = 14) study (from November 1990 to November 1992). Immediately before arterial cross-clamping, patients were given an intravenous bolus of either enoxaparin (ENX), 75 anti-Xa IU/kg (n = 100), or unfractionated heparin (UFH), 50 IU kg (n = 101). Meanwhile the saphenous vein or a prosthetic graft was flushed with ENX (25,000 anti-Xa IU) or UFH (25,000 IU) in 250 ml of saline solution. Subsequent treatment consisted of subcutaneous administration of ENX, 75 anti-Xa IU/kg, or UFH, 150 IU kg, beginning 8 hours after the intravenous injection and then every 12 hours thereafter for 10 days. The primary end point was graft patency on day 10 +/- 2 after surgery as assessed clinically and/or by arteriography on day 10 +/- 2 and/or during reintervention or autopsy. Analysis of patients on an intention-to-treat basis (patients who received at least on injection of ENX or UFH and who had at least one end-point evaluation) showed that graft thrombosis occurred in 30 of 199 cases: eight (8%) in the ENX group and 22 (22%) in the UFH group (p = 0.009). Among the 131 patients who were evaluated by arteriography before day 12, twelve (9.1%) had graft thrombosis: four (6%) in the ENX group and eight (12.5%) in the UFH group (NS). There were no significant differences between the two groups in terms of safety--that is, there were 12 major hemorrhages in each group, and during the follow-up period five patients in the ENX group died compared to nine in the UFH group (NS). These results indicate that ENX is as safe as but more effective than UFH when used for the prevention of early graft thrombosis in patients undergoing femorodistal reconstructive surgery.