Efficacy of perioperative thromboprophylactic agents in the maintenance of anastamotic patency and survival of rat microvascular free groin flaps

We sought to determine the thromboprophylactic effects of low-molecular-weight heparin (LMWH) and pentoxifylline. Randomized blinded study. Sixty Sprague-Dawley rats were assigned to 1 of 4 treatment groups: (1) control group (n = 15), (2) pentoxifylline group (n = 15), (3) LMWH group (n = 15), and (4) combined therapy group (n = 15). A groin/abdominal free flap was elevated in each, with division of the artery and microvascular repair The animals received therapy for 4 days preoperatively and 6 days postoperatively. Flaps were monitored visually, and on the seventh postoperative day, the flap was elevated, and the microvascular anastomosis was assessed for patency. There was a statistically significant improvement in arterial patency in both pentoxifylline and LMWH groups compared with controls ( P < 0.01) but no significant improvement with combined therapy ( P > 0.05). In this animal model, LMWH and pentoxifylline have significant thrombroprophylactic effects when used individually but not in combination.