Esophageal pH increments associated with post‐reflux swallow‐induced peristaltic waves show the occurrence and relevance of esophago‐salivary reflex in clinical setting

AbstractBackgroundFollowing acid perfusion, esophageal pH is restored by swallowed bicarbonate‐containing saliva secreted in response to a vagal esophago‐salivary reflex. At impedance‐pH monitoring, the post‐reflux swallow‐induced peristaltic wave (PSPW) index puts into relationship timely post‐reflux swallows with the number of reflux events: Low values typify reflux‐related heartburn (RRH) and lack of on‐therapy improvement characterizes proton pump inhibitor (PPI) failure. Considerable esophageal pH increments associated with PSPWs could demonstrate the occurrence of esophago‐salivary reflex in clinical setting, while its relevance could be shown by lower esophageal pH increments in PPI‐refractory RRH.MethodsProspective multicenter study in patients with PPI‐refractory or PPI‐responsive RRH evaluated with off‐PPI impedance‐pH monitoring. Increments in pH associated with PSPWs were measured and the mean calculated to obtain the PSPW‐associated ∆pH.Key ResultsThe mean PSPW‐associated ∆pH in 294 RRH patients was 1.2 ± 0.7 and was lower in 137 PPI‐refractory (1.0 ± 0.6) than in 157 PPI‐responsive (1.5 ± 0.6) cases (p < 0.0001). Lower PSPW‐associated ∆pH was independently related to PPI failure at multivariable logistic regression analysis (OR 0.16, 95% CI 0.09–0.26). At ROC analysis, comparing PPI‐refractory to PPI‐responsive cases the AUC for PSPW‐associated ∆pH was 0.76 (95% CI 0.71–0.82), the best cutoff value being 1.2.Conclusions and InferencesConsiderable PSPW‐associated pH increments demonstrate the occurrence of esophago‐salivary reflex in clinical setting. Lower increments in PPI‐refractory RRH cases show the clinical relevance of esophago‐salivary reflex, confirming that PSPW represents a defense mechanism against reflux. PSPW‐associated ∆pH can efficiently predict PPI response in patients undergoing off‐therapy impedance‐pH monitoring.