High-resolution Manometry in Treated Achalasia: Scoping Review and Novel Nomenclature.

Background & aims: Chicago Classification (CC) for high-resolution manometry (HRM) is the standard for diagnostic criteria of primary motility disorders, achalasia being the most relevant. CC does not include recommendations on HRM in treated achalasia, either after surgery or endoscopic interventions.

Methods: After systematic review of literature on 3 major databases (Pubmed/MEDLINE, Embase, Web of Science) from inception to December 2024, a group of 12 esophageal motility experts provided recommendations for HRM interpretation in treated achalasia and proposed novel nomenclature and management flowchart to address gaps in diagnostic CC hierarchy.

Results: The search yielded 40 articles on HRM in treated achalasia. Unsuccessful achalasia treatment results in high-integrated relaxation pressure (IRP) and obstructive features especially on provocative maneuvers. We propose the term treated achalasia with outflow obstruction (TAOO) instead of achalasia. Conversely, the term adequately treated achalasia (ATA) is suggested in the absence of obstructive features, instead of absent contractility or ineffective motility, which could be misleading. We propose an IRP cutoff of the upper limit of normal according HRM system utilized, similar to that recommended for the naïve sphincter by CC to describe incomplete sphincter relaxation despite treatment. Intrabolus pressurization and abnormal IRP on rapid drink challenge (RDC) are additional obstructive features. Assessment of body contractility, either ineffective (<450 mmHg.cm.s) or spastic (<4.5 sec), is relevant to disease profiling. HRM combined with impedance represents a valuable tool to assess esophageal emptying.

Conclusions: This scoping review with expert recommendations provides guidance for HRM interpretation in treated achalasia and introduces novel descriptive terms to describe pathophysiology following achalasia treatment. Conventional CC should not be used in treated achalasia description.