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Background Acid exposure time ( AET) is considered the most useful parameter to predict response of reflux-related heartburn to medical or surgical treatment. However, recent studies showed high rates of heartburn response to proton pump inhibitor ( PPI) therapy in patients with normal AET. We aimed to compare the efficacy of postreflux swallow-induced peristaltic wave ( PSPW) index and mean nocturnal baseline impedance ( MNBI) with AET in linking PPI-responsive heartburn to reflux. Methods Off-therapy impedance- pH tracings from 425 patients, 317 with PPI-responsive and 108 with PPI-refractory heartburn were blindly re-analyzed. Demographic and endoscopic characteristics, conventional impedance- pH variables, PSPW index, and MNBI were assessed with multivariate logistic regression to identify factors independently associated with PPI responsiveness. Prediction models were developed to assess the strength of reflux linkage with factors independently associated with PPI responsiveness by calculating the area under the curve ( AUC) at receiver-operating-characteristic ( ROC) analysis. Key Results At multivariate logistic regression analysis, AET, MNBI, and PSPW index were the only factors independently associated with PPI responsiveness, abnormal values found in 60%, 76%, and 92% of PPI-responsive cases ( P<.017). At ROC analysis, PSPW index ( AUC:.794, P=.002) and MNBI ( AUC: 0.742, P=.003), both separately and combined ( AUC: 0.811, P<.001) linked reflux with PPI-responsiveness better than AET ( AUC: 0.687). Conclusions & Inferences AET, PSPW index, and MNBI are independently associated with PPI-responsive heartburn. PSPW index and MNBI can link PPI-responsive heartburn to reflux better than AET and should become part of the standard analysis of impedance- pH tracings. [ABSTRACT FROM AUTHOR]

Background On-therapy impedance- pH monitoring in proton pump inhibitor ( PPI)-refractory gastroesophageal reflux disease ( GERD) yielded conflicting results. We aimed to assess the diagnostic value of postreflux swallow-induced peristaltic wave ( PSPW) index and mean nocturnal baseline impedance ( MNBI) in PPI-refractory heartburn. Methods On-therapy impedance- pH tracings from 189 consecutive patients with PPI-refractory heartburn were blindly reviewed. Patients were subdivided into refractory reflux esophagitis ( RRE), healed reflux esophagitis ( HRE), non-erosive reflux disease ( NERD), and functional heartburn ( FH) according to endoscopic and conventional impedance- pH findings. The diagnostic accuracy of PSPW index and MNBI in separating NERD from FH was assessed with receiver-operating-characteristic ( ROC) analysis. Objectively documented persistent reflux remission at 3-year follow-up in 53 patients who underwent laparoscopic fundoplication served to evaluate PSPW index and MNBI as independent predictors of PPI-refractory GERD confirmed by positive surgical outcome. Key Results Median PSPW index and MNBI values were significantly lower in 39 RRE (16%; 1145 Ω) than in 41 HRE (25%; 1741 Ω) and in 68 NERD (29%; 2374 Ω) patients, and in all three GERD subgroups compared to 41 FH cases (67%; 3488 Ω) ( P<.008). At ROC analysis, comparing NERD to FH the area under the curve was 0.886 with PSPW index and 0.677 with MNBI ( P=.005). PSPW index was an independent predictor of PPI-refractory GERD (odds ratio 0.6983, P=.012). Conclusions & Inferences At on-therapy impedance- pH monitoring, PSPW index and MNBI efficiently distinguish PPI-refractory NERD from FH. The PSPW index represents an independent predictor of PPI-refractory GERD. [ABSTRACT FROM AUTHOR]