Alex W Nielsen, BS, Melissa C Helm, BS, Matthew Bosler, BA, Jon C Gould, MD. Medical College of Wisconsin
Background: Morbidly obese patients are at an increased risk for venous thromboembolism (VTE, considered either a DVT or a PE) after bariatric surgery. When a perioperative bleeding event occurs, routine chemical thromboprophylaxis (most often low molecular weight heparin) is often withheld. The decision about when or even if to start VTE prophylaxis once the bleeding seems to have stopped is difficult secondary to concerns about inciting another bleeding event. We sought to evaluate the relationship between perioperative bleeding necessitating transfusion and the incidence of postoperative VTE in bariatric surgery patients.
Methods and Procedures: The American College of Surgeons-National Surgical Quality Improvement Program (NSQIP) dataset between 2012 and 2014 was queried to identify patients who underwent bariatric surgery (n=59,424). Gastric bypass (n=28,268), sleeve gastrectomy (n=30,258), bariatric revision (n=418), and biliopancreatic diversion procedures were included (n=480). Univariate and multivariate regression were used to determine perioperative factors predictive of post-operative VTE within 30-days of surgery in patients to experience a bleeding complication necessitating transfusion.
Results: From the entire study sample, DVT was diagnosed an average of 14.3 days post-surgery, while PE presented at 12.1 days. Patients diagnosed with a post-operative VTE were more likely to have another major complication compared to patients who did not have a VTE (21.3% vs 3.2%; p<0.0001). Predictive risk factors of VTE included: blood transfusion, BMI, length of hospital stay, male sex, procedure type, history of severe COPD, ASA classification of III or IV, bleeding disorder, reoperation, any renal complication, any cardiac complication, any pulmonary complication, any infection, and CVA (p < 0.05). Multivariate regression analysis of patients who received a blood transfusion revealed a significantly increased risk of subsequent VTE (Odds Ratio [OR]=4.81; p<0.0001). If a patient who received a perioperative transfusion also had a pulmonary complication, the risk of VTE increased considerably (OR=89.1, p<0.0001).
Conclusions: Bariatric surgery patients who receive a postoperative blood transfusion are at a substantially increased risk for VTE – especially if they also experience a subsequent pulmonary complication. The etiology of VTE in those who are transfused is likely multifactorial and related to an increased rate of reoperation, a gap in chemical thromboprophylaxis in patients who bleed, and perhaps to a hypercoagulable state induced by the prior transfusion. In those who bleed, consideration should be given to reinitiating chemical thromboprophylaxis when safe, conducting a screening ultrasound of the lower extremities, and possibly even placing vena cava filter in patients at highest risk.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 79534
Program Number: P553
Presentation Session: Poster (Non CME)
Presentation Type: Poster
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