The Incidence of Pulmonary Embolism in Open versus Laparoscopic Gastric Bypass

Obesity independently increases the risk of pulmonary embolism (PE). We compare a superobese population (body mass index [BMI] > 55 kg/m²) undergoing open gastric bypasses (OGBs) with a similarly matched group of laparoscopic gastric bypasses (LGB) to see if the incidence of PE differs. We included all patients undergoing OGB (n = 193, average BMI = 51 kg/m²) at our institution by a single surgeon between July 1999 and April 2001. Thirty-one patients were superobese (BMI > 55 kg/m²). LGB was started at our institution in April 2001. Since that time 213 patients (average BMI = 52 kg/m²) have undergone the procedure. One hundred and nine patients were superobese. Pre- and postoperative prophylaxis included sequential compression stockings and subcutaneous heparin. Postoperatively, patients who developed signs of hypoxia, tachypnea, or tachycardia underwent a chest X-ray and spiral computed tomography. In addition, all patients who expired in the 30-day postoperative period underwent postmortem examination. Data were analyzed using the chi-squared test. In the OGB group, four patients (2.1%) developed PE. All occurred in superobese patients with a BMI > 55 kg/m². Three were fatal PEs and one was nonfatal. None of these patients had a prior history of deep vein thrombosis, PE, venous stasis disease, or pulmonary hypertension. In the LGB group, one patient (0.9%) had a nonfatal PE. This patient had a history of deep vein thrombosis. The incidence of PE was statistically higher in the superobese OGB group (P < 0.01). Despite the theoretical hindrance to venous return and vena caval compression observed with pneumoperitoneum, fewer PEs occurred in the laparoscopic group. Our data, however, suggest that patients with a BMI > 55 kg/m² might be at an increased risk for PE independent of operative approach.