Diagnosis of Esophageal Motility Disorders: Esophageal Pressure Topography vs. Conventional Line Tracing

Abstract

Objectives: Enhanced characterization of esophageal peristaltic and sphincter function provided by esophageal pressure topography (EPT) offers a potential diagnostic advantage over conventional line tracings (CLT). However, high-resolution manometry (HRM) and EPT require increased equipment costs over conventional systems and evidence demonstrating a significant diagnostic advantage of EPT over CLT is limited. Our aim was to investigate whether the inter-rater agreement and/or accuracy of esophageal motility diagnosis differed between EPT and CLT.

Methods: Forty previously completed patient HRM studies were selected for analysis using a customized software program developed to perform blinded independent interpretation in either EPT or CLT (six pressure sensors) format. Six experienced gastroenterologists with a clinical focus in esophageal disease (attendings) and six gastroenterology trainees with minimal manometry experience (fellows) from three academic centers interpreted each of the 40 studies using both EPT and CLT formats. Rater diagnoses were assessed for inter-rater agreement and diagnostic accuracy, both for exact diagnosis and for correct identification of a major esophageal motility disorder.

Results: The total group agreement was moderate (κ=0.57; 95% CI: 0.56-0.59) for EPT and fair (κ=0.32; 0.30-0.33) for CLT. Inter-rater agreement between attendings was good (κ=0.68; 0.65-0.71) for EPT and moderate (κ=0.46; 0.43-0.50) for CLT. Inter-rater agreement between fellows was moderate (κ=0.48; 0.45-0.50) for EPT and poor to fair (κ=0.20; 0.17-0.24) for CLT. Among all raters, the odds of an incorrect exact esophageal motility diagnosis were 3.3 times higher with CLT assessment than with EPT (OR: 3.3; 95% CI: 2.4-4.5; P<0.0001), and the odds of incorrect identification of a major motility disorder were 3.4 times higher with CLT than with EPT (OR: 3.4; 2.4-5.0; P<0.0001).

Conclusions: Superior inter-rater agreement and diagnostic accuracy of esophageal motility diagnoses were demonstrated with analysis using EPT over CLT among our selected raters. On the basis of these findings, EPT may be the preferred assessment modality of esophageal motility.

Figure 1. Study schema

Raters were randomized to the order of analysis (i.e., either esophageal pressure topography or conventional line tracing first). At least two weeks after completion of the first analysis, each rater analyzed the same 40 patient studies (re-ordered and re-coded) in the alternate display format than his/her first analysis.

Figure 2. Examples of manometry analysis software

Examples of single swallows from two patients included in the study are demonstrated in both esophageal pressure topography (EPT, left) and conventional line tracing (CLT, right). For CLT analysis, studies included pressure sensors placed in the stomach, through the center of the lower esophageal sphincter (LES) in the deglutitive window, at 3, 8, and 13 cm above the EGJ, and at the upper esophageal sphincter. Deglutitive LES relaxation was measured in EPT with the 4-second integrated relaxation pressure (IRP, white boxes) and in CLT by the residual LES pressure (difference between the LES nadir pressure and the gastric pressure). Both the single sensor LES pressure (green line) and 6cm eSleeve pressure (orange line) were provided for LES assessment in CLT. 2A) Normal swallow: This patient was diagnosed as normal by both EPT and CLT reference standards, diagnosed as normal by 12/12 raters with EPT, and 9/12 by CLT [one fellow diagnosed the patient as ineffective esophageal motility (IEM) and two fellows as isolated hypertensive LES]. 2B) Achalasia: This patient was diagnosed as type I achalasia (EPT) and classic achalasia (CLT) by the reference standards, type I achalasia by 11/12 raters with EPT (one fellow diagnosed as type II achalasia), and classic achalasia by 4/12 raters with CLT (4 attendings and four fellows diagnosed the patient as IEM).

Figure 2. Examples of manometry analysis software

Examples of single swallows from two patients included in the study are demonstrated in both esophageal pressure topography (EPT, left) and conventional line tracing (CLT, right). For CLT analysis, studies included pressure sensors placed in the stomach, through the center of the lower esophageal sphincter (LES) in the deglutitive window, at 3, 8, and 13 cm above the EGJ, and at the upper esophageal sphincter. Deglutitive LES relaxation was measured in EPT with the 4-second integrated relaxation pressure (IRP, white boxes) and in CLT by the residual LES pressure (difference between the LES nadir pressure and the gastric pressure). Both the single sensor LES pressure (green line) and 6cm eSleeve pressure (orange line) were provided for LES assessment in CLT. 2A) Normal swallow: This patient was diagnosed as normal by both EPT and CLT reference standards, diagnosed as normal by 12/12 raters with EPT, and 9/12 by CLT [one fellow diagnosed the patient as ineffective esophageal motility (IEM) and two fellows as isolated hypertensive LES]. 2B) Achalasia: This patient was diagnosed as type I achalasia (EPT) and classic achalasia (CLT) by the reference standards, type I achalasia by 11/12 raters with EPT (one fellow diagnosed as type II achalasia), and classic achalasia by 4/12 raters with CLT (4 attendings and four fellows diagnosed the patient as IEM).

Figure 3. Diagnostic accuracy of esophageal motility disorders

Pooled assessment of all rater patient diagnoses by comparison with the reference standard diagnosis. Numbers represent the number of patients in each category. Disagreement with the reference standard on the exact diagnosis, but correct identification of a major motility disorder was considered mild inaccuracy. Incorrect identification of a major motility disorder was considered a major inaccuracy.