Characterizing reflux on high resolution esophageal manometry with impedance

Background In some patients, reflux at esophagogastric junction (EGJ) can be seen on the impedance portion of the high-resolution esophageal manometry with impedance (HREMI) studies. How this correlates with reflux on conventional esophageal reflux monitoring studies is unknown. We aimed to: (1) determine prevalence of reflux seen on HREMI, (2) correlate reflux during HREMI with reflux on esophageal reflux monitoring studies. Methods Patients undergoing HREMI and ambulatory reflux monitoring (7/2019 to 2/2020) were studied. Healthy volunteers (HVs) underwent HREMI. Key results Sixteen HVs underwent HREMI (no reflux on HREMI = 13, reflux on 1 swallow on HREMI = 3). Of 229 patients (mean age 56.4 +/- 1.0, 68.1% females) undergoing HREMI, 47 (20.5%) had pathologic reflux at EGJ on HREMI (reflux on >= 2 swallows). The patients with reflux on HREMI had more frequent reflux events on multichannel intraluminal impedance-pH (MII-pH) than patients without reflux on HREMI (63.5 +/- 7.1 vs 42.1 +/- 2.3, p = 0.01). On ambulatory pH monitoring, 113 (49.3%) had GERD and 42 (18.3%) borderline results. Patients with reflux on HREMI more commonly had GERD (56.3% vs 48.6%) and borderline results (28.1% vs 18.3%) than patients without reflux on HREMI (p = 0.01). Reflux on >= 2 swallows on HREMI had a specificity of 83.6% and sensitivity of 24.8% for GERD. Reflux on >= 5 swallows on HREMI improved specificity to 91.4%, with sensitivity of 14.2% for GERD. Conclusions and inferences Amongst patients undergoing HREMI, 20.5% had pathologic reflux at EGJ on HREMI. Patients with reflux on HREMI more frequently had GERD on ambulatory pH monitoring. Reflux on HREMI had good specificity but low sensitivity for GERD.