Derangement of esophageal anatomy and motility in morbidly obese patients: a prospective study based on high-resolution impedance manometry.

Background: Morbidly obese patients often suffer from gastroesophageal reflux disease (GERD). High-resolution impedance manometry (HRIM) allows a comprehensive evaluation of esophageal motility and esophagogastric junction (EGJ) morphology and helps to clarify GERD pathophysiology.

Objective: To evaluate the esophageal function and EGJ anatomy in morbid obesity by HRIM.

Setting: University Hospital, Taiwan.

Methods: We consecutively enrolled 57 morbidly obese patients planning to undergo bariatric surgery and 58 healthy volunteers in this prospective study. All patients responded to validated symptom questionnaires and underwent fasting blood tests, HRIM, and esophagogastroduodenoscopy. We compared anthropometric and HRIM parameters between the 2 groups, and analyzed correlations between the GERD symptom scores and clinical variables in the obese patients.

Results: The obese patients, comprising 30 males (53%), had a median age of 35 years and body mass index of 40.5 kg/m. The 4-second integrated relaxation pressure in the lower esophageal sphincter was significantly higher in the patients than the volunteers (median: 10.8 versus 5.6 mm Hg; P < .001). EGJ outflow obstruction and ineffective esophageal motility were diagnosed in 16% and 11% of the patients, respectively, versus 5% and 28% of the volunteers (P = .022). Manometric hiatal hernia (m-HH) was present in 19 (33%) of the patients and none of the volunteers; all m-HH were associated with erosive esophagitis. Most of the patients were considered as no GERD by the validated questionnaires, regardless of the presence of m-HH and erosive esophagitis.

Conclusions: The obese patients had a higher lower esophageal sphincter 4-second integrated relaxation pressure and higher prevalence of EGJ outflow obstruction and m-HH than the healthy volunteers. The presence of m-HH was strongly associated with erosive esophagitis. The absence of GERD symptoms in morbid obesity was not necessarily suggestive of negative esophagogastroduodenoscopy and HRIM findings, and the discrepancy existed between esophagogastroduodenoscopy and HRIM for diagnosing HH. A comprehensive evaluation of the EGJ anatomy and esophageal function may be considered before bariatric surgery.