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.