Chicago Classification update (version 4.0): Technical review on diagnostic criteria for achalasia

Area of Science:

• Gastroenterology
• Esophageal Motility Disorders
• Diagnostic Criteria

Background:

• The Chicago Classification (CC) is the standard for diagnosing esophageal motility disorders.
• High-resolution manometry (HRM) provides key metrics for achalasia diagnosis.
• Recent updates in CC version 4.0 (CCv4.0) refine achalasia subtyping and diagnostic criteria.

Purpose of the Study:

• To outline the updated diagnostic criteria for achalasia subtypes based on CCv4.0.
• To differentiate between conclusive and inconclusive HRM diagnoses of achalasia.
• To provide guidance on further investigations and diagnostic algorithms for achalasia.

Main Methods:

• Review and interpretation of the CCv4.0 guidelines for achalasia.
• Analysis of HRM metrics including integrated relaxation pressure (IRP) and panesophageal pressurization (PEP).
• Definition of criteria for achalasia types I, II, and III, and for inconclusive diagnoses.

Main Results:

• CCv4.0 defines conclusive achalasia by abnormal median IRP and failed peristalsis.
• Achalasia subtypes (I, II, III) are distinguished by peristaltic patterns and PEP.
• Inconclusive HRM diagnoses require supportive testing like timed barium esophagram (TBE) or functional lumen imaging probe (FLIP).

Conclusions:

• CCv4.0 provides refined diagnostic criteria for achalasia subtypes using HRM.
• A clear distinction between conclusive and inconclusive HRM findings is established.
• A diagnostic algorithm incorporating supportive testing is recommended for achalasia evaluation.