391 How Useful Is Prolonged 96 Hr versus 48 Hr Wireless pH Monitoring in PPI Refractory GERD?

Abstract

INTRODUCTION: Gastroesophageal reflux disease (GERD) is a common problem. Ambulatory pH monitoring has been used to identify pathological esophageal acid exposure and reflux-symptoms association in GERD, especially when endoscopy is normal, but the utility of prolonged 96 hr monitoring and if PPI therapy during study facilitates better management is unclear. The purpose of the study is to evaluate the clinical utility of prolonged 96 hr wireless pH monitoring, before and after PPI therapy. METHODS: We conducted a retrospective study of adult patients presenting to our center between January 2015 and June 2018 with suspected diagnosis of GERD and refractory to PPI therapy. Consecutive patients who underwent 96 hr wireless pH monitoring (Bravo®, Medtronics, Minneapolis, MN) placed endoscopically, 6 cm above LES zone were enrolled. Patients were instructed to stop PPI therapy 7 days prior to the study and to resume their usual PPI therapy on day 3 and day 4 of study. The percent time of esophageal acid exposure (pH < 4) for each day during supine and upright positions and GI symptoms were analyzed using (SPSS™) version 22. Patients were excluded if the entire 96 hr study was not recorded either from battery malfunction or capsule detachment. Data compared between those with normal and abnormal pH study, and between first 48 hrs and next 48 hrs. RESULTS: 64 patients met inclusion criteria (Table 1). 42 (65%) patients had elevated >4.5%. Total 24 hr acid exposure time; 38% on either D1 or D2 and 62 % on both days and 22 (35 %) had normal acid reflux study (Figure 1, Table 2). Of patients with abnormal study, 23/42 (54.7%) had persistent increase in % acid exposure time on D3 and 17/42 (40.4%) patients on D4 following PPI therapy. CONCLUSION: Our study demonstrates that prolonged 96 hr pH monitoring is feasible and clinically useful. We confirmed abnormal acid reflux in 65% of patients and normal acid reflux in 35%. Also, the abnormal reflux profile normalized in 36% of patients on their usual PPI whereas 64% had persistent abnormal acid reflux, despite their usual PPI therapy. Thus 96 hr testing allows improved diagnosis of day time or supine acid reflux symptoms, and identifies patients who are either refractory or responsive to current PPI therapy. This test could improve management of patients with PPI refractory GERD.