Prophylaxis of Venous Thromboembolism with Low Molecular Weight Heparin in Bariatric Surgery: a Prospective, Randomised Pilot Study Evaluating Two Doses of Parnaparin (BAFLUX Study)

BACKGROUND: The optimal dose of low molecular weight heparin (LMWH) to prevent venous thromboembolism (VTE) after bariatric surgery remains controversial. The aim of this multicentre, open-label, pilot study was to evaluate the efficacy and safety of two different doses of the LMWH parnaparin administered to patients undergoing bariatric surgery. METHODS: Patients were randomised to receive 4,250 IU/day (group A) or 6,400 IU/day (group B) of parnaparin s.c. for 7–11 days. Bilateral colour Doppler ultrasound of the lower limb was performed before surgery and at the end of the treatment period. The primary efficacy outcome was a composite of asymptomatic and symptomatic deep vein thrombosis, symptomatic pulmonary embolism and death from any cause during treatment. The primary safety endpoint was major and clinically relevant non-major bleeding. RESULTS: A total of 258 patients underwent randomization; 8 subjects were excluded following the safety analysis. One hundred thirty-one patients [106 females; mean age, 40.3 years (standard deviation (SD) ±9.6); mean body mass index (BMI), 44.6 kg/m(2) (SD ±5.4)] were assigned to group A and 119 patients [93 females; mean age, 41.5 years (SD ±9.9); mean BMI, 44.2 kg/m(2) (SD ±5.4)] were assigned to group B. The rate of the primary efficacy outcome was 1.5 % (two cases; 95 % confidence interval (CI), 0.2–6.0 %) in group A as compared with 0.8 % (one case; 95 % CI, 0.4–5.3 %) in group B (p = ns). The composite incidence of major bleeding and clinically relevant non-major bleeding was 6.1 % (eight cases; 95 % CI, 2.9–12.1 %) in group A and 5.0 % (six cases; 95 % CI, 2.1–11.1 %) in group B (p = ns). CONCLUSIONS: A parnaparin dose of 4,250 IU/day seems suitable for VTE prevention in patients undergoing bariatric surgery.