Duration of surgery independently influences risk of venous thromboembolism after laparoscopic bariatric surgery.

BACKGROUND: Obesity is a recognized risk factor for venous thromboembolism (VTE). The aims of the present study were to determine the risk factors for symptomatic VTE in morbidly obese patients undergoing laparoscopic bariatric surgery.
METHODS: This was a retrospective study that included consecutive patients who had undergone bariatric surgery from January 2007 to May 2010. Thromboprophylaxis included routine application of low-molecular-weight heparin, pneumatic calf compression, and early ambulation. Extensive measures, such as temporary insertion of a caval filter (n = 5) and anticoagulation (n = 11), were used in selected higher risk patients. The patients were followed up for a minimum of 3 months after surgery to determine the incidence of clinical VTE. The results are presented as the mean and range.
RESULTS: A total of 500 consecutive patients aged 44.7 years (range 19-77) with a body mass index of 49.2 kg/m(2) (range 32.1-84.3) underwent laparoscopic bariatric surgery (442 gastric bypass, 20 sleeve gastrectomy, and 38 gastric banding). No conversions to open surgery occurred, and the operative time, morbidity rate, and mortality rate was 93.7 minutes (range 20-325), 2.8%, and .2%, respectively. No clinical deep vein thrombosis was encountered, although 3 patients (.6%) developed pulmonary embolism. Cox regression multivariate analysis identified the operative time as the only independent predictor of postoperative VTE (relative risk .0002 per min, P = .009). Multivariate analysis identified the body mass index as an independent predictor of the operating time.
CONCLUSION: Increasing obesity was associated with a longer operative time, which consequently increased the risk of VTE.