Chicago Classification update (v4.0): Technical review of high-resolution manometry metrics for EGJ barrier function

Area of Science:

• Gastroenterology
• Physiology
• Medical Diagnostics

Background:

• Esophagogastric junction (EGJ) barrier function is critical in gastroesophageal reflux disease (GERD) pathophysiology.
• Impaired EGJ function can lead to esophagitis due to excessive acid exposure.
• High-resolution manometry (HRM) metrics are being evaluated for clinical use in GERD assessment.

Purpose of the Study:

• To evaluate potential HRM metrics for assessing EGJ integrity for inclusion in Chicago Classification v4.0.
• To address the complexity of the EGJ, comprising both the crural diaphragm (CD) and lower esophageal sphincter (LES).
• To determine consensus on specific EGJ metrics and their clinical significance.

Main Methods:

• Consideration of several potential EGJ integrity metrics: LES-CD separation, EGJ contractile integral (EGJ-CI), respiratory inversion point (RIP), and intragastric pressure.
• Evaluation of metrics for their ability to capture EGJ barrier function attributes.
• Discussion of measurement standardization and interpretation thresholds.

Main Results:

• Strong recommendations for LES-CD separation to indicate hiatus hernia, though a definitive threshold was not agreed upon.
• No consensus on the clinical significance of the RIP, only its localization in hiatus hernia cases.
• Agreement on EGJ-CI measurement methodology, but wide variation in thresholds for hypotensive EGJ.
• Intragastric pressure recognized as important but lacking agreed-upon thresholds for abdominal obesity.

Conclusions:

• No single HRM metric fully captures EGJ barrier function due to its complex physiology.
• Further research and consensus are needed to establish reliable numerical thresholds for key EGJ metrics.
• Standardized HRM metrics are essential for accurate GERD diagnosis and management.