ORLANDO — Several factors predict an increased likelihood of deep vein thrombosis and/or pulmonary embolism for morbidly obese patients undergoing Roux-en-Y gastric bypass surgery, according to the results of a study presented by Rodrigo Gonzalez, M.D., at the annual meeting of the American Society for Bariatric Surgery.
Obesity is a major risk factor for perioperative deep vein thrombosis (DVT) and pulmonary embolism (PE). PE occurs in 2% of patients undergoing any surgical procedure, and it is responsible for 150,000 deaths in the United States each year, Dr. Gonzalez said. In bariatric surgery, the incidence of PE is estimated as 0.8%–4%, and the incidence of DVT as 0.6%–2%.
To identify the risk factors associated with these complications, the study looked at 660 consecutive patients undergoing Roux-en-Y gastric bypass. Prospectively collected data were reviewed by Dr. Gonzalez and his associates in the Interdisciplinary Obesity Treatment Group, department of surgery, University of South Florida, Tampa.
All patients received antithrombotic prophylaxis with heparin and sequential compression devices. Patients with a prior history of DVT, PE, or hypercoagulable diseases received inferior vena cava (IVC) filters; however, this practice was adopted only partway through the study, so some patients treated early did not receive the filters.
Postoperative low-molecular-weight heparin was dosed according to body mass index. Patients with a BMI less than 50 kg/m
The researchers used Doppler ultrasound to diagnose DVT. PE was diagnosed on the basis of clinical, necropsy, and/or radiologic findings. The radiologic techniques included CT angiography and ventilation/perfusion scans. In patients with IVC filters, DVT was diagnosed using duplex ultrasound; these patients had mainly lower-extremity DVTs.
In all, 9 patients developed DVT, 6 developed PE, and 7 developed both DVT and PE, to give a total of 16 patients with DVT (2.5% incidence) and 13 with PE (2% incidence). These figures are consistent with values reported in the literature.
A multivariate analysis, comparing the group that developed DVT, PE, or both complications with patients who did not, showed that a significantly greater number were older than 50 years (50% vs. 29%) or had an anastomotic leak (32% vs. 3%), a history of smoking (23% vs 7%), or a history of DVT and/or PE (23% vs. 7%).
An open surgical technique and revision operations also were more common in the group that developed DVT, PE, or both complications.
Additional screening is warranted in patients with one or more of these risk factors before Roux-en-Y gastric bypass, Dr. Gonzalez said. He added that supplementary postoperative prophylaxis might be warranted.