Reproducibility patterns of multiple rapid swallows during high resolution esophageal manometry provide insights into esophageal pathophysiology

BackgroundMultiple rapid swallows (MRS) during esophageal high resolution manometry (HRM) assess esophageal neuromuscular integrity by evaluating postdeglutitive inhibition and rebound contraction, but most reports performed only a single MRS sequence. We assessed patterns of MRS reproducibility during clinical HRM in comparison to a normal cohort. MethodsConsecutive clinical HRM studies were included if two separate MRS sequences (four to six rapid swallows 4s apart) were successfully performed. Chicago Classification diagnoses were identified; contraction wave abnormalities were additionally recorded. MRS-induced inhibition (contraction 3cm during inhibition phase) and rebound contraction was assessed, and findings compared to 18 controls (28.00.7year, 50.0% female). Reproducibility consisted of similar inhibition and contraction responses with both sequences; discordance was segregated into inhibition and contraction phases. Key ResultsMultiple rapid swallows were successfully performed in 89.3% patients and all controls; 225 subjects (56.2 +/- 0.9year, 62.7% female) met study inclusion criteria. Multiple rapid swallows were reproducible in 76.9% patients and 94.4% controls (inhibition phase: 88.0% vs 94.4%, contraction phase 86.7% vs 100%, respectively, p=ns). A gradient of reproducibility was noted, highest in well-developed motor disorders (achalasia spectrum, hypermotility disorders, and aperistalsis, 91.7-100%, p=ns compared to controls); and lower in lesser motor disorders (contraction wave abnormalities, esophageal body hypomotility) or normal studies (62.2-70.8%, p<0.0001 compared to well-developed motor disorders). Inhibition phase was most discordant in contraction wave abnormalities, while contraction phase was most discordant when studies were designated normal. Conclusions & InferencesMultiple rapid swallows are highly reproducible, especially in well-developed motor disorders, and complement the standard wet swallow manometry protocol.