E0206 - Does Lower Esophageal Sphincter Distensibility Measured by the Functional Lumen Imaging Probe Relate to Total Esophageal Acid Exposure Time?

Brendan Kemple, MD¹, James Miller, BS², Steven Clayton, MD^3
1Wake Forest Baptist Medical Center, Augusta, GA; ²Wake Forest University School of Medicine, Winston-Salem, NC; ³Wake Forest Baptist Medical Center, Winston-Salem, NC

Introduction: Proper evaluation of lower esophageal sphincter (LES) physiology is imperative in assessing esophageal motility. LES function is directly assessed through Functional Lumen Impedance Planimetry (FLIP) distensibility index (DI) measurement, which can be utilized to support complementary tests of LES physiology. 24-hour pH impedance monitoring, primarily utilized in the diagnosis of GERD, also indirectly examines LES function.
The aim of this study is to characterize the relationship between LES distensibility measured by FLIP and esophageal acid exposure time measured by 24-hour pH impedance monitoring to determine how FLIP contributes to the diagnosis of GERD.

Methods: A retrospective review of 146 patients was performed. Patients were classified as unmedicated or medicated during their pH monitoring. The unmedicated group was subclassified by normal (< 4%), indeterminate (4-6%), or abnormal ( >6%) acid exposure time. The medicated group was subclassified by normal (< 1.2%) or abnormal ( >1.2%) acid exposure time. Mean DI at 60mL (16cm FLIP) was calculated for the each of the 6 groups. An ANOVA and a t-test was utilized to determine if mean DI varied by acid exposure classification within the unmedicated and medicated groups, respectively.
Within each medicated or unmedicated population, patients were additionally grouped by normal or abnormal DI using two thresholds for normality ( >2.8 mm2/mmHg and >2.0 mm2/mmHg). Average acid exposure time was calculated for each of the groups and compared via t-testing.

Results: In unmedicated patients, the average DIs were not significantly different at 3.4, 3.1 and 3.5 in patients with acid exposure time < 4%, 4-6%, and >6%, respectively (p = 0.94). In medicated patients, the average DIs were not significantly different at 4.17 and 3.81 in patients with acid exposure time < 1.2% and >1.2%, respectively (p = 0.541).
There was no significant difference in mean acid exposure times between patients with normal and abnormal DIs within both the unmedicated and medicated groups (Table 1).

Discussion: In both medicated and unmedicated patient groups, DI and acid exposure time were unrelated. These results suggest that while both DI and acid exposure time are valid indicators of LES dysfunction, an increased DI as measured by FLIP did not correlate to increased acid exposure time from 24-hour pH impedance monitoring. LES distensibility, which plays a major role in disorders of the esophagogastric junction, may not be as useful in characterizing GERD.



Disclosures:


Brendan Kemple, MD¹, James Miller, BS², Steven Clayton, MD³. E0206 - Does Lower Esophageal Sphincter Distensibility Measured by the Functional Lumen Imaging Probe Relate to Total Esophageal Acid Exposure Time?, ACG 2022 Annual Scientific Meeting Abstracts. Charlotte, NC: American College of Gastroenterology.