Measuring esophageal compliance using functional lumen imaging probe to assess remodeling in eosinophilic esophagitis

Background: Eosinophilic esophagitis (EoE) is associated with fibrostenotic remodeling that can be objectively assessed using the functional lumen imaging probe (FLIP). This is typically done using a metric called distensibility plateau (DP). We aimed to describe a novel measure of compliance of the esophageal body and evaluate the associated clinical characteristics in EoE. Methods: One hundred seventy-one adult patients with EoE (mean (SD) age 38 (12) years), 31% female and 35 healthy, asymptomatic controls who completed 16-cm functional luminal imaging probe (FLIP) during endoscopy, were evaluated in a cross-sectional study. The esophageal body DP and compliance were measured using a customized analysis program, with compliance calculated as (Δ esophageal body volume)/(Δ pressure) between two FLIP-filled volumes. Results: In controls, the median (5–95th percentile) DP was 19.8 mm (17.9–21) and esophageal body compliance was 0.37 ml/mmHg (0.18–1.1), which was greater than in EoE (DP 19 (11–21)), compliance 0.19 (0.02–0.71), p-values <0.001. Among EoE patients, 70 (41%) had normal compliance (>0.2 ml/mmHg) and normal DP (>17 mm); 11 (6%) had normal compliance and reduced DP; 34 (20%) had reduced compliance and normal DP; and 56 (33%) had reduced compliance and reduce DP. Patients with both reduced compliance and DP had the greatest proportion of severe rings (61% with EREFS score 2–3) and stricture (100%). Conclusion: FLIP provides an objective evaluation of biomechanical properties of the esophageal wall that appears enhanced by complementary application of metrics of DP and esophageal body compliance.