Post-reflux swallow-induced peristaltic wave (PSPW): physiology, triggering factors and role in reflux clearance in healthy subjects

• Published in: Journal of gastroenterology Vol. 55; no. 12; pp. 1109 - 1118
• Main Authors: Zhang, Mengyu, Yaman, Busra, Roman, Sabine, Savarino, Edoardo, Gyawali, C. Prakash, Gardner, Jerry D., Sifrim, Daniel
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.12.2020; Springer; Springer Nature B.V
• Subjects: Abdominal Surgery; Asymptomatic; Colorectal Surgery; Gastroenterology; Hepatology; Medicine; Medicine & Public Health; Original Article―Alimentary Tract; Original ―Alimentary Tract; Physiology; Surgical Oncology; Gastroesophageal reflux; Esophageal clearance; Esophageal peristalsis
• DOI: 10.1007/s00535-020-01732-5
• ISSN: 0944-1174; 1435-5922

Background and aims The underlying physiology of post-reflux swallow-induced peristaltic wave (PSPW) is unclear. We aimed to: 1) calculate the probability of a random association between reflux and PSPW; 2) characterize factors that could underlie triggering of PSPW and 3) assess the chemical clearance effect of PSPW in healthy asymptomatic subjects. Methods A total of 251 impedance–pH tracings from healthy asymptomatic subjects were analysed. Twenty consecutive tracings from this pool with 20–40 reflux episodes/24 h and a PSPW index higher than 50% were separately analyzed to evaluate the probability of a random association between reflux and PSPW. The characteristics of reflux episodes followed by a PSPW were compared with those not associated with PSPW. Results A mean time interval of 29.3 s between a reflux episode and the first swallow captured 71% of total reflux episodes, and 67% of accompanying swallows were non-random. Compared to reflux without PSPW, reflux episodes with PSPW were more frequently acidic ( P  = 0.048), mixed with gas ( P  < 0.0001), of high proximal extent ( P  < 0.0001), while awake ( P  < 0.0001), and with shorter chemical clearance time ( P  = 0.040). High proximal extent, gas presence and occurring while awake were independent factors associated with PSPW ( P  < 0.0001). Conclusion Using a time window between reflux and PSPW of around 30 s, the probability of a chance association is around 30%. Reflux episodes with high proximal extent, containing gas and occurring while awake are important factors associated with PSPW in healthy subjects. Reflux episodes with PSPW have a shorter chemical clearance time.