766 Can 24-Hour pH-Impedance Monitoring on Therapy Predict Outcome of Laparoscopic Fundoplication in Patients With Refractory Reflux Symptoms?

different in P2 (-,+) and P3 (+,-). Hypervigilance and body awareness scores were elevated in all 4 groups. While hypervigilance did not differ by phenotype, it accounted for 50% of patient reported symptom severity [GERDQ] [B= .52, t = 3.8, p = .00]. Conclusion: PPINR undergoing 96h Bravo capsule monitoring had similar psychological profiles regardless of reflux phenotype, suggesting that psychological factors may drive symptoms independent of physiological parameters. In this population, visceral sensitivity was elevated as expected in P1 (+/+) and P2 (+/-). However, all groups had elevated hypervigilance scores, and these scores predicted symptom severity independent of reflux phenotype. Additional characterization of hypervigilance and hypersensitivity may inform management in this refractory population. Funded by NIH DK092217 Table 1. Psychological profile by reflux phenotype

766 Can 24-Hour pH-Impedance Monitoring on Therapy Predict Outcome of Laparoscopic Fundoplication in Patients With Refractory Reflux Symptoms? Marie Desjardin, Guillaume Luc, Denis Collet, Frank Zerbib

†

Introduction: The treatment of gastroesophageal reflux (GER) refractory symptoms is challenging. Available data are scarce but some studies have suggested that esophageal pHimpedance monitoring on therapy may be useful to select patients for surgery. This monocenter retrospective study assessed the value of preoperative pH-impedance monitoring on therapy to predict functional outcome after laparoscopic Toupet fundoplication in patients with refractory reflux symptoms. Patients and methods: Thirty five patients (19 female patients, median age 46 years, range 17 - 64 years) with a preoperative pH-impedance monitoring on PPIs twice daily were assessed at least 6 months after a laparoscopic Toupet fundoplication for GER refractory symptoms (heartburn and/or regurgitation). Failure of fundoplication was defined by a Visick score > 2. Post-operative symptoms were assessed by the RDQ questionnaire. The pH-impedance parameters analyzed were number of GER events (total, acid, non-acid), esophageal acid exposure, esophageal bolus exposure, and symptom-reflux association for heartburn and regurgitation defined by Symptom Index (SI)> 50% and Symptom Association Probability (SAP) > 95%. Thirty-three of these 35 operated patients had preoperative pH-impedance considered as positive with at least one of these parameters above normal values previously determined (1) Results: After a mean follow-up of 40.5 (range 7-102.2) months, 8/35 (22.9%) patients were considered as failures. Compared to patients with favourable outcome, these patients were younger (34.5 vs. 47 yrs, p = 0.08), and more often on PPI therapy (75% vs. 22%, p = 0.01). Female gender (75% vs. 48%, p = 0.24) and preoperative esophagitis (38% vs. 52%, p=0.69) were similar in both groups. Patients with failure had higher RDQ scales in each domain: heartburn (p < 0.05), regurgitation (p < 0.05) and dyspepsia (p < 0.05). 7/8 patients who failed had a positive pHimpedance monitoring on therapy. Preoperative positive SAP for regurgitation was the only parameter statistically associated with successful postoperative outcome (0/8 vs. 11/27, p = 0.037). Conclusion: This retrospective study shows that the failure of fundoplication is high (23%) in patients with refractory GER symptoms, despite the use of pre-operative pHimpedance monitoring on PPIs. The only parameter associated with favourable outcome is the positive association between reflux and regurgitation pre-operatively. These results should be confirmed by prospective controlled studies. (1) Zerbib et al, CGH 2013 ;11:366-72.

Statistically Significant

Figure 1: Comparison of Post-Reflux Swallow-Induced Pressure Wave-Index (PSPW-I) in Patients with Non-Obstructive Dysphagia (NOD) vs those without NOD. •= Mean Values

765 Symptom Reporting Among PPI Non Responders May Be Driven by Esophageal Hypervigilance and Not Reflux Phenotype Laurie Keefer, Jenna Craft, Kate Dowjotas, Ian J. Kahrilas, Sabine Roman, John E. Pandolfino

767 Strength of Reflux Evidence on pH-Impedance Testing Stratifies Symptomatic Reflux Outcome on Prospective Evaluation Amit Patel, Gregory S. Sayuk, C. Prakash Gyawali

Background: Patients with persistent troublesome heartburn symptoms on at least a standard FDA approved dose of PPI therapy are a heterogenous group referred to as PPI nonresponders (PPINR). These patients are routinely referred for ambulatory reflux monitoring to determine the physiologic mechanism of their refractory GERD and classified into 1 of 4 phenotypes in order to determine next steps for treatment: P1(+symptom; +reflux); P2(-symptom; +reflux); P3 (+symptom, -reflux); P4(- symptom, - reflux). Unfortunately, research from our group has demonstrated that typical reflux parameters (symptom index, symptom associated probability, acid exposure, symptom reflux correlation) are of limited value in explaining PPINR and do not really inform treatment. We hypothesized that while mechanisms for persistent reflux despite PPI use may differ physiologically, PPINR may share features of esophageal hypersensitivity and hypervigilance, which independently drive symptom experience. Methods: PPINRs were taken off PPIs for 10 days prior to undergoing upper endoscopy with 96h Bravo ph capsule placement at an academic Esophageal Center. Patients were categorized into reflux phenotypes based on results of pH testing. Patients also completed the GERDQ and other questionnaires focused on hypersensitivity, hypervigilance, and psychological distress. Data was analyzed in SPSSv21 using oneway ANOVA and linear regression. Descriptive data is reported as means and standard deviation. Results: 66 patients participated [mean age = 50.0(13.7)yrs, 44%male]. Phenotypes (P) did not statistically differ from each other on any questionnaire variables. Psychological distress parameters (depression, anxiety, somatization) were within normal limits for all groups. Heartburn catastrophizing was elevated but not different in P3 (+,-). Visceral hypersensitivity was elevated but not

Background: pH-impedance monitoring allows assessment of acid exposure times (AET), numbers of reflux events, and symptom-reflux association with both pH detected and impedance detected reflux events. Combinations of these reflux parameters describe varying confidence in the presence of reflux disease. We compared outcomes between cohorts with distinct pre-identified reflux parameters defining strength of reflux evidence. Methods: 187 patients (53.8±0.9 yr, 70.6% F) undergoing pH-impedance testing on or off PPI for persisting reflux symptoms over a 5-yr period were prospectively followed over 3.3±0.1 years. Patients underwent either medical therapy or antireflux surgery (ARS) at the discretion of their referring physicians. Symptoms were assessed on questionnaires (dominant symptom intensity (DSI): product of symptom frequency and severity assessed on 5-point Likert scales; global symptom severity (GSS) on 100-mm visual analog scales) at baseline and on followup. Symptom association probability (SAP) was calculated separately for pH- and impedancedetected reflux events. Reflux evidence was categorized as strong (abnormal AET and positive SAP), good (abnormal AET but negative SAP), functional reflux hypersensitivity (FRH, normal AET with positive SAP), and equivocal. Demographics (age, gender, race), symptom presentation, baseline DSI and GSS, and outcomes (linear and ‡50% improvement in DSI and GSS) were compared between cohorts. Results: Of 187 patients, 26 (13.9%) had strong reflux evidence, 37 (19.8%) had good reflux evidence, 53 (28.3%) had FRH, and 37 (19.8%) had equivocal or no reflux evidence. These four groups had similar demographics, PPI status

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of dysphagia in patients with GERD symptoms. However, depressed PSPW-I is seen in both pathological GERD and FH. Impaired PSPW-I may therefore represent a maladaptive response to both physiologic and pathologic levels of reflux. Table 1: Characteristics of Non-Obstructive Dysphagia (NOD) vs Non-NOD Patients