Experimental Thromboprophylaxis with Low Molecular Weight Heparin After Microsurgical Revascularization

There is great variability among microsurgeons as regards the use of prophylactic anticoagulant after revascularization and this is probably due to lack of comparative data. Also, there has been much debate regarding the benefit of anti-thrombotic therapies versus the risk of complications such as systemic bleeding and hematoma formation. To evaluate the effectiveness of postoperative low molecular weight heparin (LMWH) as a prophylactic anticoagulant therapy after microsurgical repair of the femoral artery and vein in rats. Randomized, blinded study. The femoral artery and vein of 40 Sprague Dawley rats were sectioned and repaired with microsurgical sutures under general anesthesia. They were randomly divided into 2 groups: Group (A) in which the 20 rats were injected with Enoxaparin subcutaneously at a dose 1.5 mg/kg once daily for 3 successive days; Group (B), the control group, in which 20 rats were injected with isotonic sodium chloride 0.9 % subcutaneously in a blinded fashion. After 7 days, the femoral vessels were re-explored and patency of the femoral vessels was assessed with empty-and-refill test. There were a total of 12 vascular thrombosis among 74 microsurgical repair in both groups with percentage of 16.22 % including, 5 arterial anastomosis and 7 venous anastomosis. The incidence of thrombosis in the treatment group (A) was 18.4 % while the incidence of thrombosis in the control group (B) was 13.8 %. This difference was not statistically significant using Fisher exact test. Postoperative administration of LMWH did not provide the desired protection against thrombosis after microsurgical vascular repair.