Su1069 Diagnosis of Gastro-Esophageal Reflux Disease (GERD) and Prediction of Treatment Response to Proton Pump Inhibitors (PPI) by Prolonged Wireless pH Monitoring: A Prospective Assessment

Introduction: Gastroesophageal reflux (GER) causes esophageal and extra-esophageal symptoms.Frequent extra-esophageal symptoms are cough, laryngospasm, laryngitis and asthma.Micro-and macro-aspiration are hypothesized pathophysiologic mechanisms.Aim: to compare the results obtained with two techniques that can measure reflux in the hypo-pharynx.Methods: The "Restech technique" evaluate the pH at the level of the hypo-pharynx through a probe with a pH-antimony sensor which is placed behind the soft palate.Mutichannel intraluminal impedance/pH-monitoring (MII/pH) records the passage gas and liquid reflux, and the pH of the latter, through a probe with 6 impedance sensors and 2 pH antimony sensors (the lower at 3 cm above the LES and the high at the level of hypo-pharynx).Ten adults patients (age 46.33 ± 9.86yrs; range 33.9-66.11)presenting with chronic coughing underwent simultaneous a Restech and MII/pH recording.A time-interval of 2 minutes was allowed between Restech and MII/pH to be considered simultaneous episodes.The results were statistically tested with the Chi-square test; a p value <0.05 was considered significant.Results: A total of 515 reflux episodes were measured with the MII/pH (acid: 181; weakly acid: 310; weakly alkaline: 24).180 (35%) of these episodes reached the highest impedance channel (hypo-pharynx).However, 74/180 (41%) of these reflux episodes were not related to a change in pH according to the antimony electrode of the MII/pH catheter.With the Restech technique, we found 87 reflux episodes; 35 (40%) of these did correlate with swallows (and thus not with reflux) according to the impedance recording, and 39 (45%) were not associated with impedance or pH modification according to MII/pH.Out of all the reflux episodes detected, only 13 (15%)were detected simultaneously with both techniques (2.5 % for impedance versus 15% with Restech; p: 0.0002).Moreover, we found 49 pH-only reflux events at the pH sensor in the hypo-pharynx with the MII/pH; of them, only 3 (6.1%)were correlated in time with Restech detected reflux.Correlation in time (2 minutes time-interval) between cough and reflux events was positive in 5/10 patients for impedance (symptom index 5/10, symptom association probability 4/10).Correlation in time between cough and reflux was positive in 0/10 patients according to Restech technique.Discussion: Our results show that Restech detected less reflux episodes than impedance; 35% of the reflux events according to Restech were swallows according to impedance.Moreover, time correlation between cough and reflux could not be demonstrated with Restech.