Clinical pulmonary embolus after gastric bypass surgery.

Background: Pulmonary embolus (PE) is one of the most common causes of death for patients undergoing gastric bypass surgery. The risk of developing PE has been associated with increased age, greater body mass index (BMI), and chronic venous stasis disease.

Methods: Between 1998 and 2003, 1225 patients underwent open Roux-en-Y gastric bypass (RYGBP) surgery (258 men and 967 women) for the treatment of morbid obesity and its related disorders. The medical records for morbidly obese patients diagnosed with PE after RYGBP were identified. The presenting signs and symptoms were reviewed, and the known risk factors were analyzed. We compared the age and BMI of these patients with those of a randomly selected RYGBP control group. The Mann-Whitney U test was used to analyze the statistical significance of the results.

Results: During the study period, 11 patients were diagnosed with PE (0.9%). Six patients were men and five were women, for a gender-specific incidence of PE of 2.3% in men and 0.5% in women. The average BMI was 62.5 kg/m(2) in the men and 59.1 kg/m(2) in the women, much greater than in the control group (men 53 kg/m(2) and women 52 kg/m(2); P <0.005 and P <0.05, respectively). All male patients were super-obese (BMI >50 kg/m(2)). The total number of super-obese patients undergoing RYGBP during the study period was 147, for an incidence of PE in super-obese men of 4%. Nine of the 11 patients developed PE after discharge from the hospital within an average of 10 days.

Conclusion: The super-obese male patient is at a much greater risk of developing PE than other RYGBP patients (relative risk 4.4). The risk extends to several weeks after discharge. Therefore, extending PE prophylaxis to several weeks after surgery may be warranted.