Autopsy findings following gastric bypass surgery for morbid obesity.

BACKGROUND: Roux-en-Y gastric bypass, currently the most frequently performed surgical procedure for morbid obesity, has a low but significant mortality rate. There are limited data documenting the findings at necropsy in patients who have died following this procedure. OBJECTIVE: To determine cause of death and pathologic processes present in obese subjects dying after gastric bypass surgery. PATIENTS: We studied 10 patients who underwent autopsy following gastric bypass surgery for morbid obesity between the years 1994 and 2000. RESULTS: There were 6 men and 4 women. The mean age of the patients was 48 years (range, 28-62 years). The mean preoperative weight was 162 kg (range, 112-245 kg), and the mean body mass index was 54 kg/m(2) (range, 39-76 kg/m(2)), similar to all patients undergoing gastric bypass at our institution during the same period. Five deaths were directly attributable to technical complications. Five deaths were attributed to underlying comorbid conditions. One patient died of cirrhosis and one of pulmonary hemorrhage. Three patients died from pulmonary embolism. However, 8 of 10 patients had microscopic evidence of pulmonary emboli, despite prophylaxis for deep vein thrombosis. Most patients had some degree of steatohepatitis and hepatic fibrosis (80% and 70%, respectively). There were no deaths from primary cardiac events. CONCLUSIONS: In patients who die after Roux-en-Y gastric bypass, half die due to technical complications, whereas the other half die of complications of their obesity. Clinically, only 20% of patients were suspected to have pulmonary emboli, yet at autopsy, 80% of patients had pulmonary emboli. In morbidly obese patients undergoing Roux-en-Y gastric bypass, there is an unexpectedly high rate of clinically silent pulmonary emboli contributing to morbidity and mortality.