Impaired esophageal function in morbidly obese patients with gastroesophageal reflux disease: evaluation with multichannel intraluminal impedance

Background: Morbid obesity is associated with gastroesophageal reflux disease (GERD), and both have an independent association with motility disorders. Impaired esophageal function is thought to play a role in the development of dysphagia after fundoplication and bariatric procedures (especially restrictive procedures). The authors aimed to define both the physiology and the underlying pathophysiology of swallowing using a novel technique, multichannel intraluminal impedance (MII), which can accurately determine the clearance of a swallowed bolus through the esophagus, in combination with traditional manometry, which can measure peristalsis. Methods: Simultaneous MII, manometry, and pH monitoring were performed for 10 asymptomatic subjects, 22 consecutive nonobese patients with GERD (GERD), and 22 consecutive morbidly obese patients with GERD (MO-GERD) who were under evaluation for antireflux and bariatric surgery at the University of Washington. In this study, MII was defined as abnormal if less than 80% of swallowed liquid boluses cleared the esophagus completely. Results: All GERD and MO-GERD patients had abnormal pH monitoring. The manometric findings were similar for the GERD and MO-GERD patients. All the asymptomatic subjects had normal manometry and impedance test results. Abnormal manometry would have predicted that approximately 23% of GERD and MO-GERD patients had defective emptying. However, when measured with impedance, esophageal clearance was found to be defective in two times as many GERD and nearly three times as many MO-GERD patients. Conclusions: In patients with GERD, impedance often detects impairments in esophageal motility not identified by manometry. Morbidly obese patients with GERD have a higher incidence of impaired esophageal motility than nonobese patients with GERD. This may have implications for bariatric procedures, especially those that are restrictive.