Achalasia: A New Clinically Relevant Classification by High-Resolution Manometry

Background & Aims: Although the diagnosis of achalasia. hinges on demonstrating impaired esophagogastric junction (EGJ) relaxation and aperistalsis, 3 distinct patterns of aperistalsis are discernable with high-resolution manometry (HRM). This study aimed to compare the clinical characteristics and treatment response of these 3 subtypes. Methods: One thousand clinical HRM studies were reviewed, and 213 patients with impaired EGJ relaxation were identified. These were categorized into 4 groups: achalasia with minimal esophageal pressurization (type 1, classic), achalasia with esophageal compression (type II), achalasia. with spasm (type III), and functional obstruction with some preserved peristalsis. Clinical and manometric variables including treatment response were compared among the 3 achalasia subtypes. Logistic regression analysis was performed using treatment success as the dichotomous dependent variable controlling for independent manometric and clinical variables. Results: Ninety-\nine patients were newly diagnosed with achalasia (21 type 1, 49 type II, 29 type III), and 83 of these had sufficient follow-up to analyze treatment response. Type II patients were significantly more likely to respond to any therapy (BoTox [71%], pneumatic dilation [91%], or Heller myotomy [100%]) than type 1 (56% overall) or type III (29% overall) patients. Logistic regression analysis found type II to be a predictor of positive treatment response, whereas type III and pretreatment esophageal dilatation were predictive of negative treatment response. Conclusions: Achalasia. can be categorized into 3 subtypes that are distinct in terms of their responsiveness to medical or surgical therapies. Utilizing these subclassifications would likely strengthen future prospective studies of treatment efficacy in achalasia.