Venous thromboembolism after bariatric surgery performed by Bariatric Surgery Center of Excellence Participants: analysis of the Bariatric Outcomes Longitudinal Database

Abstract

Background: Venous thromboembolism (VTE) is an uncommon complication of bariatric surgery but a leading cause of postoperative mortality. Studying the factors predictive of low-incidence complications requires the analysis of large cohorts. The Bariatric Outcomes Longitudinal Database, the world's largest prospective database for bariatric surgery, has provided a suitable medium for analyzing low-frequency events.

Methods: The data in the Bariatric Outcomes Longitudinal Database from 73,921 research-consented patients who had undergone bariatric surgery by a participant in the American Society for Metabolic and Bariatric Surgery Bariatric Surgery Center of Excellence program before September 22, 2009, were analyzed for VTE events within 90 days after surgery.

Results: The overall risk of VTE within 90 days after surgery was .42%, and 73% of these events occurred after discharge, most within 30 days after surgery. The risk of VTE was greater in the patients undergoing gastric bypass than in those undergoing adjustable gastric banding (.55% versus .16%). VTE was more frequent when the procedure was performed using an open than a laparoscopic approach (1.54% versus .34%). Patients with a VTE event were older (+4.9 yr), had had a greater preoperative body mass index (+3.9 kg/m(2)), and were more likely to have a history of VTE (16.5% versus 3.7%). The risk of VTE was greater in men (hazard ratio 2.32, 95% confidence interval 1.81-2.98) and in patients with an inferior vena cava filter (hazard ratio 7.66, 95% confidence interval 4.55-12.91).

Conclusion: The overall risk of VTE was low in the population treated by participants in the Bariatric Surgery Center of Excellence program, where clinical pathways to prevent VTE have been mandated. Analysis of this large study population allowed the identification of patient characteristics correlating with increased risk of postoperative VTE and the variable effectiveness of VTE prophylaxis methods.