New measures of upper esophageal sphincter distensibility and opening patterns during swallowing in healthy subjects using EndoFLIP®

Background This paper aims to measure upper esophageal sphincter (UES) distensibility and extent and duration of UES opening during swallowing in healthy subjects using EndoFLIP (R). Methods Fourteen healthy subjects (20-50 years) were recruited. An EndoFLIP (R) probe was passed trans-orally and the probe balloon was positioned across the UES. Two 20-mL ramp distensions were completed and UES cross-sectional area (CSA) and intra-balloon pressure (IBP) were evaluated. At 12-mL balloon volume, subjects completed dry, 5- and 10-mL liquid swallows and extent (mm) and duration (s) of UES opening and minimum IBP (mmHg) were analyzed across swallows. Key Results Thirteen subjects completed the study protocol. A significant change in UES CSA (P < .001) and IBP (P < .000) was observed during 20-mL distension. UES CSA increased up to 10-mL distension (P <.001), from which point IBP raised significantly (P = 0.004). There were significant changes in UES diameter (mm) (P < .000) and minimum IBP (mmHg) (P < .000) during swallowing events. Resting UES diameter (4.9 mm; IQR 0.02) and minimum IBP (18.8 mmHg; IQR 2.64) changed significantly during dry (9.6 mm; IQR 1.3: P < .001) (3.6 mmHg; IQR 4.1: P = 0.002); 5 mL (8.61 mm; IQR 2.7: P < .001) (4.8 mmHg; IQR 5.7: P < .001) and 10-mL swallows (8.3 mm; IQR 1.6: P < 0.001) (3 mmHg; 4.6: P < .001). Median duration of UES opening was 0.5 s across dry and liquid swallows (P = 0.91). Color contour plots of EndoFLIP (R) data capture novel information regarding pharyngo-esophageal events during swallowing. Conclusions & Inferences Authors obtained three different types of quantitative data (CSA, IBP, and timing) regarding UES distensibility and UES opening patterns during swallowing in healthy adults using only one device (EndoFLIP (R)). This new measure of swallowing offers fresh information regarding UES dynamics which may ultimately improve patient care.