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Background: Roux-en-Y gastric bypass (RYGB) is an effective surgery for weight loss in obese patients. Current guidelines recommend advancement to regular diet in 1-2 months post-RYGB. Failure to advance or dietary intolerance may have clinical and nutritional implications. A prior study suggested that up to 30% of post-RYGB patients may develop dysphagia. RYGB may affect the Vagal innervation to the esophagus, and the resultant esophageal dysmotility may play a role in post-RYGB dietary complications. Understanding esophageal motor functions by high-resolution manometry (HRM) and their association with dietary outcome post-RYGB may allow more effective, targeted therapy for symptoms and dietary complications.
Aim: To investigate the association between esophageal motor dysfunctions on HRM and intolerance to solid diet among post-RYGB patients.
Methods: This was a retrospective cohort study of post-RYGB patients who underwent HRM at a tertiary care center in 6/2007-5/2012. Patients with underlying esophageal dysmotility pre-RYGB, HRM performed less than 2 months after RYGB, or need for parenteral or tube feeding were excluded. The primary outcome was diet at the time of HRM (liquid [LD] vs solid [SD]). Esophageal motor characteristics were extracted from HRM. Fisher-exact or chi-squared test for binary variables and student's t-test for continuous variables were used to assess for differences between LD and SD groups. Multivariate analysis was performed using forward stepwise logistic regression.
Results: 63 patients met inclusion criteria (age 51±10.3 yrs, 91% F), and 21 subjects (33.3%) could only tolerate LD. Patients on LD were more likely to have at least one abnormal parameter on HRM than those on SD (61.9% vs 28.6%, p=0.01). Univariate analyses showed that elevated basal lower esophageal sphincter (LES) pressure (9.52% vs 0%, p=0.04), incomplete LES relaxation (22% vs 0%, p= 0.04), increased esophageal body contraction amplitude (119±56 vs 93±41 mmHg, p=0.05), and dysphagia (52% vs 16%, p= 0.003) were significantly associated with LD. On multivariate analysis, incomplete LES relaxation remained an indepedent predictor for LD (OR 11.73, p=0.02).
Conclusions: Post-RYGB patients unable to tolerate SD are more likely to have abnormal findings on HRM. Incomplete LES relaxation is independently associated with LD use, while other hypermotility patterns (hypertensive LES and increased esophageal body contraction) are also more prevalent. In addition to pouch or anastomotic abnormalities, esophageal motor dysfunction should be considered in assessing post-RYGB patients' failure to tolerate SD. HRM should play a role in evaluating post-RYGB dietary complications. Future studies should examine the potential causes of this dysfunction and explore the effect of therapies targeting LES relaxation on clinical and dietary outcome.