24-h multichannel intraluminal impedance-pH monitoring may be an inadequate test for detecting gastroesophageal reflux in patients with mixed typical and atypical symptoms

The detection of gastroesophageal reflux (GERD) via pH testing is the key component of the evaluation of patients considered for antireflux surgery. Two common pH testing systems exist, a multichannel, intraluminal impedance-pH monitoring (MII-pH) catheter, and wireless (Bravo(A (R))) capsule; however, discrepancies between the two systems exist. In patients with atypical symptoms, MII-pH catheter is often used preferentially. We aimed to elucidate the magnitude of this discrepancy and to assess the diagnostic value of MII-pH and the Bravo wireless capsule in a population of patients with mixed respiratory and typical symptoms. The study population consisted of 66 patients tested with MII-pH and Bravo pH testing within 90 days between July 2009 and 2013. All patients presented with laryngo-pharyngo-respiratory (LPR) symptoms. Patient demographics, symptomatology, manometric and endoscopic findings, and pH monitoring parameters were analyzed. Patients were divided into four comparison groups: both pH tests positive, MII-pH negative/Bravo positive, MII-pH positive/Bravo negative, and both pH tests negative. Nearly half of the patients (44 %) had discordant pH test results. Of these, 90 % (26/29) had a negative MII-pH but positive Bravo study. In this group, the difference in the DeMeester score was large, a median of 29.3. These patients had a higher BMI (28.5 vs. 26.1, p = 0.0357), were more likely to complain of heartburn (50 vs. 23 %, p = 0.0110), to have a hiatal hernia, (85 vs. 53 %, p = 0.0075) and a structurally defective lower esophageal sphincter (LES, 85 vs. 58 %, p = 0.0208). In patients with LPR symptoms, we found a high prevalence of discordant esophageal pH results, most commonly a negative MII-pH catheter and positive Bravo. As these patients exhibited characteristics consistent with GERD (heartburn, defective LES, hiatal hernia), the Bravo results are likely true. A 24-h MII-pH catheter study may be inadequate to diagnose GERD in this patient population.