Marc A Ward, MD, Christy M Dunst, MD, Ezra N Teitelbaum, MD, Valerie J Halpin, MD, Kevin M Reavis, MD, Lee L Swanstrom, MD, Steven R DeMeester, MD. The Oregon Clinic
Introduction: The gold standard for the objective diagnosis of gastroesophageal reflux disease (GERD) is ambulatory pH monitoring off medications. Increasingly, impedance-pH (MII-pH) monitoring on medications is being used to evaluate refractory symptoms. The aim of this study was to determine whether an MII-pH test on medications can reliably detect the presence of GERD in patients referred for antireflux surgery.
Methods: Patients referred between December 2010 to September 2016 for persistent reflux symptoms despite pH confirmed adequate acid suppression (DeMeester score ≤ 14.7) were reviewed retrospectively. All patients who originally had MII-pH testing on medications, were re-evaluated with an off medication Bravo-pH study by protocol. Acid exposure results (defined by an off medication Bravo) were compared to the original on medication MII-pH.
Results: There were 49 patients that met study criteria (median age 51). All patients had normal acid exposure during their MII-pH test on medications (average DeMeester score 4.35). Impedance was abnormal (normal < 47) in 25 of the 49 patients (51%) and the median number of reflux events in these patients was 77. On subsequent Bravo-pH off medications, 37 patients (75.7%) showed increased esophageal acid exposure (average DeMeester score 36.4). Bravo-pH testing was abnormal in 84% of patients with abnormal MII testing and in 67% with normal MII testing. The sensitivity and specificity of an abnormal MII-pH on medications for increased esophageal acid exposure off medications was 56.8% and 66.7% respectively. The positive predictive value of confirming GERD from an abnormal MII-pH on medications is 84%, while the negative predictive value is 33.3%. A receiver operating characteristic (ROC) curve was generated and the area under the curve was 0.71, indicating that MII-pH on medications is classified as a fair test (0.7-0.8) in diagnosing pathologic GERD.
Conclusion: Compared to the gold standard (pH testing off medications), MII-pH on medications does not reliably confirm the presence of GERD in patients referred for antireflux surgery. Since an excellent outcome with antireflux surgery is dependent on the presence of GERD, patients should not be offered antireflux surgery until GERD is confirmed with pH testing off medications.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 80565
Program Number: S095
Presentation Session: Foregut 2
Presentation Type: Podium