Prophylaxis of Venous Thromboembolism Using Two Different Doses of Low-Molecular-Weight Heparin (Nadroparin) in Bariatric Surgery: A Prospective Randomized Trial

Background: Obese patients undergoing bariatric surgery are at a high risk of developing fatal pulmonary embolism or post-thrombotic syndrome. The prophylactic use of low molecular weight heparins (LMWHs) is correlated with a significant reduction in post-operative venous thrombosis in patients undergoing orthopedic or general surgery. In morbidity obese patients, the limited number of comparative trials are too sparse to allow a consensus on the effective dose and dosing schedule. Methods: In a prospective study to evaluate the effect of two doses of nadroparin as prophylaxis for venous thromboembolism following bariatric surgery, 60 consecutive patients undergoing Roux-en-Y gastric bypass were randomized to receive either 0.6 ml (5700 IU) or 1.0 ml (9500 IU) of nadroparin started pre-operatively and then given once daily post-operatively until discharge. Results: No statistically significant differences between the two groups were detected in any of the measured coagulation parameters either preoperatively or at days 1, 3 and 5 postoperatively. No thrombotic events were observed pre- or post- operatively, and no patient developed meta-thrombotic syndrome at the 3 and 6 months follow-up. No bleeding events occurred in the patients given the lower dose compared with two major hemorrhages in those given the higher dose. Conclusion: Our results indicate that 0.6 ml (5700 IU) of nadroparin once daily is safe and well-tolerated, and it is as effective in prophylaxis of venous thromboembolism as the higher dose of 1 ml (9500 IU), in such high risk oatients.