Routine upper GI series after gastric bypass does not reliably identify anastomotic leaks or predict stricture formation

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Abstract
Many surgeons who perform Roux-en-Y gastric bypass (RYGB) for morbid obesity routinely obtain an upper gastrointestinal (GI) series in the early postoperative period to search for anastomotic leaks and signs of stricture formation at the gastrojejunostomy. We hypothesized that this practice is unreliable. We analyzed 654 consecutive RYGBs, of which 63% were completed laparoscopically. An upper GI series was obtained in 634 (97%) patients. The radiographic findings (leak or delayed emptying) were compared with clinical outcomes (leak or stricture formation) to calculate the sensitivity and specificity. Univariate analysis identified risk factors for leaks or stricture formation; events were too few for multivariate analysis. Of 634 routine upper GI series, anastomotic leaks at the gastrojejunostomy were diagnosed in 5 (0.8%); 2 of these 5 were later reinterpreted as artifacts. Four leaks were not seen on the initial upper GI series, yielding an overall sensitivity of 43% and a positive predictive value (PPV) of 60%. Univariate analysis showed that cases done early (odds ratio [OR] 5.4 for the first 100 cases, p = 0.02) and prolonged operating time (OR 7.8 for cases ≥ 300 min, p = 0.01) were associated with leaks. Emptying into the Roux-en-Y limb was delayed in 127 (20%) of the upper GI series. Strictures requiring dilatation developed in 16 (2.4%) patients. The PPV of delayed emptying for stricture formation was 6%. Risk factors for stricture formation included stapled anastomosis (OR 7.8, p = 0.002), surgeon inexperience (OR 2.9 for first 50 cases, p = 0.04), and delayed emptying (OR 3.3; p = 0.02). Because the incidence of anastomotic complications and the sensitivity of upper GI series were both low, routine upper GI series did not reliably identify leaks or predict stricture formation. A selective approach, whereby imaging is reserved for patients with clinical evidence of a leak or stricture, may be more appropriate.