Primary Peristalsis Is the Dominant Mechanism of Refluxate Clearance Following Gastroesophageal Reflux

Background: Refluxate volume and pH drop following gastroesophageal reflux are mostly cleared by peristalsis. We evaluated the roles of primary volume clearing peristaltic wave (VCPW), secondary VCPW, post-reflux swallow-induced peristaltic wave (PSPW), and late primary peristaltic wave (LPPW) in refluxate clearance. Methods: We retrospectively analyzed pH-impedance studies performed off therapy in 40 patients with typical esophageal symptoms. Mechanism of refluxate clearance was evaluated for each reflux episode (primary VCPW vs. secondary VCPW vs. none), as well as presence of PSPW, LPPW when PSPW was absent, and pH recovery with each mechanism. Per-episode and per-patient analyses determined the dominant mechanism of refluxate clearance and pH recovery. Results: Of 958 reflux episodes, 88% were acidic. A primary VCPW was the dominant mechanism for volume clearance (48.4% acid, 47.8% non-acid reflux episodes), and ≥ 50% pH recovery (58.7%). Of reflux episodes lacking pH recovery, PSPW resulted in ≥ 50% pH recovery in 40.2%, and LPPW in 60.9%. In logistic regression models, primary peristaltic wave (primary VCPW, PSPW, or LPPW) had the highest likelihood of pH recovery in per-episode analysis (OR 2.1, CI 1.3–3.0, p < 0.001), and in per-patient analysis (OR 11.0, CI 1.5–20.5, p = 0.025), among which primary VCPW was the most effective (OR 3.4, CI 1.5–7.7, p = 0.003). Conclusions: A primary peristaltic wave from a swallow, either in the form of a VCPW, PSPW, or LPPW, is the dominant mechanism of pH recovery after gastroesophageal reflux. When a primary VCPW does not correct pH drop, PSPW, and LPPW are equivalent salvage mechanisms for pH recovery.