Postreflux swallow‐induced peristaltic wave index and nocturnal baseline impedance can link PPI‐responsive heartburn to reflux better than acid exposure time

• Published in: Neurogastroenterology and motility Vol. 29; no. 11
• Main Authors: Frazzoni, L., Frazzoni, M., Bortoli, N., Tolone, S., Furnari, M., Martinucci, I., Bertani, H., Marchi, S., Conigliaro, R., Fuccio, L., Savarino, V., Savarino, E.
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01-11-2017
• Subjects: Deglutition; Electric Impedance; esophageal baseline impedance; esophageal chemical clearance; Esophageal pH Monitoring; Female; Gastroesophageal reflux; Gastroesophageal Reflux - complications; Gastroesophageal Reflux - diagnosis; Gastroesophageal Reflux - drug therapy; GERD; Heart; Heartburn - complications; Heartburn - diagnosis; Heartburn - drug therapy; Humans; impedance‐pH monitoring; Male; Middle Aged; Peristalsis; pH effects; Proton pump inhibitors; Proton Pump Inhibitors - therapeutic use; Sensitivity and Specificity; Treatment Outcome; GERD; esophageal baseline impedance; impedance-pH monitoring; esophageal chemical clearance
• ISSN: 1350-1925; 1365-2982
• DOI: 10.1111/nmo.13116

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.
The diagnostic sensitivity of acid exposure time (AET) is limited. Postreflux swallow‐induced peristaltic wave (PSPW) index and mean nocturnal baseline impedance (MNBI) can increase the diagnostic yield of impedance‐pH monitoring. AET, PSPW index, and MNBI were the only variables independently associated with heartburn response to PPIs. PSPW index and MNBI were significantly more efficient than AET in linking PPI‐responsive heartburn with reflux. Routine assessment of impedance‐pH tracings should include calculation of PSPW index and MNBI in order to increase our ability to establish a direct relationship between PPI‐responsive heartburn and reflux.