Functional-Structural Correlates in Achalasia: The Relationship of Esophageal Pressurization and Anatomy.

Background and aims: Achalasia subtypes are classified by high-resolution manometry (HRM) based on esophageal pressurization and contractility patterns, while esophagram-based classifications emphasize esophageal anatomy. We aimed to evaluate the relationship between esophageal pressurization on HRM and esophageal anatomy on esophagram among patients with untreated achalasia.

Methods: Adult patients with treatment-naïve achalasia that completed HRM and esophagram were included. HRM achalasia subtypes were determined by the Chicago Classification with pan-esophageal pressurization (PEP) measured among type I and type II achalasia. Anatomy on esophagram was assessed using the Brazilian (esophageal width) and Japanese Esophageal Society (JES; angulation/tortuosity) classifications.

Results: 222 patients, mean (SD) age 56 (16), 49% female were included. On HRM, 32% were type I, 53% were type II, and 15% were type III achalasia. Esophageal width and JES classification differed by HRM subtype (p-values < 0.001) with type I (HRM) having greatest esophageal width (median (IQR) 5.1(4.0-6.0) cm) and most JES-C 93% (14/15), while type III achalasia had the least (width 2.6 (2.0-3.0) cm) and 0 were JES-C. Among type I and II achalasia, higher esophageal width was significantly correlated with lower median PEP and fewer swallows exceeding PEP thresholds of 10, 15, 20, or 30 mmHg.

Conclusions: HRM subtypes and PEP on HRM correlated with esophageal morphology defined on esophagram. However, imperfect concordance between HRM and esophagram classifications suggests complementary value to assess achalasia disease stages related to disease chronicity and esophageal wall mechanics. Future investigations to facilitate combined assessment with HRM and esophagram may enhance achalasia phenotyping and treatment planning.