Validation of Clinically Relevant Thresholds of Esophagogastric Junction Obstruction Using FLIP Panometry

Abstract

Background & aims: This study aimed to assess the accuracy of functional luminal imaging probe (FLIP) panometry to detect esophagogastric junction (EGJ) obstruction assigned by high-resolution manometry (HRM) and the Chicago Classification version 4.0 (CCv4.0).

Methods: Six hundred eighty-seven adult patients who completed FLIP and HRM for primary esophageal motility evaluation and 35 asymptomatic volunteers (controls) were included. EGJ opening was evaluated with 16-cm FLIP during sedated endoscopy via EGJ-distensibility index (DI) and maximum EGJ diameter. HRM was classified according to CCv4.0 and focused on studies with a conclusive disorder of EGJ outflow (ie, achalasia subtypes I, II, or III; or EGJ outflow obstruction with abnormal timed barium esophagogram) or normal EGJ outflow.

Results: All 35 controls had EGJ-DI >3.0 mm²/mmHg and maximum EGJ diameter >16 mm. Per HRM and CCv4.0, 245 patients had a conclusive disorder of EGJ outflow, and 314 patients had normal EGJ outflow. Among the 241 patients with reduced EGJ opening (EGJ-DI <2.0 mm²/mmHg and maximum EGJ diameter <12 mm) on FLIP panometry, 86% had a conclusive disorder of EGJ outflow per CCv4.0. Among the 203 patients with normal EGJ opening (EGJ-DI ≥2.0 mm²/mmHg and maximum EGJ diameter ≥16 mm) on FLIP panometry, 99% had normal EGJ outflow per CCv4.0.

Conclusions: FLIP panometry accurately identified clinically relevant conclusive EGJ obstruction as defined by CCv4.0 in patients evaluated for esophageal motor disorders. Thus, FLIP panometry is a valuable tool for both independent and complementary evaluation of esophageal motility.

Keywords: Dysphagia; Impedance; Reflux.

Figure 1.. Evaluation of esophagogastric junction (EGJ) opening parameters on FLIP Panometry.

FLIP Panometry output from four patients (A-D) are displayed as length (16-cm) x time x color-coded diameter FLIP topography (top panels) with corresponding intraballoon pressure (bottom panel). EGJ-distensibility index (DI) was calculated as the median value of three measures (dashed vertical lines 1–2-3) obtained during the 60-ml fill volume (dashed box); the maximum EGJ diameters are marked by “*”. When antegrade contractions were present, as in the patients with normal motility on high-resolution manometry (HRM) in A and B, the EGJ-DI was measured at the peak EGJ diameters that occurred in response to the pressure ramp associated with the contraction (black dashed lines). When antegrade contractions were absent, as in the patients in C (type II achalasia on HRM) and D (patient with systemic sclerosis and absent contractility on HRM), the EGJ-DI measures were obtained during expiration and at times without lower esophageal sphincter contractions (black dashed lines). Figure used with permission from the Esophageal Center of Northwestern.

Figure 2.. Association of FLIP Panometry esophagogastric junction (EGJ) opening parameters with Chicago Classification v4.0 (CCv4.0).

A) Patients with a conclusive disorder of EGJ outflow on high-resolution manometry (HRM), i.e. achalasia subtypes I, II, or III; or EGJ outflow obstruction with an abnormal timed barium esophagram. The triangles within dashed circles indicate two patients with systemic sclerosis that had a classification of type I achalasia via HRM per CCv4.0. B) Patients with an impression of normal EGJ outflow on HRM and asymptomatic controls. Patients with an inconclusive HRM per the CCv4.0 were not included in this figure. The FLIP Panometry EGJ opening classifications of reduced EGJ opening (REO), borderline reduced EGJ opening (BrEO), borderline normal EGJ opening (BnEO), and normal EGJ opening (NEO) are reflected by the colored regions of the plots; BrEO and BnEO are separated by the maximum EGJ diameter threshold at 14mm (dashed line). Figure used with permission from the Esophageal Center of Northwestern.

Figure 3.. FLIP Panometry metrics by subject cohort.

^†EGJ classification was assigned per Chicago Classification version 4.0. The ○ and * on the box-and-whisker plots reflect outlier values. Figure used with permission from the Esophageal Center of Northwestern.