Journal of Neurogastroenterology and Motility 2020; 26(2): 274-280
Characteristics of a Subset of Achalasia With Normal Integrated Relaxation Pressure
Eunju Kim,1 In Kyung Yoo,1 Dong Keon Yon,2 Joo Young Cho,1 and Sung Pyo Hong1*
Departments of 1Gastroenterology and 2Pediatrics, Cha Bundang Medical Center, Cha University College of Medicine, Seongnam, Gyeonggi-do, Korea
Correspondence to: Sung Pyo Hong, MD
Division of Gastroenterology, Department of Medicine, CHA Bundang Medical Center, CHA University School of Medicine, 59 Yatap-ro, Bundang-gu, Seongnam, Gyeonggi-do 13496, Korea
Tel: +82-31-780-5641, Fax: +82-32-780-5005, E-mail:
Eunju Kim and In Kyung Yoo contributed equally to this work.
Received: June 24, 2019; Revised: August 25, 2019; Accepted: September 20, 2019; Published online: April 30, 2020.
© The Korean Society of Neurogastroenterology and Motility. All rights reserved.

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Integrated relaxation pressure (IRP) is a critical diagnostic criterion to define achalasia. However, there are some cases with typical symptoms and signs of achalasia but with normal IRP. The aim of this study is to evaluate the clinical characteristics of patients with achalasia with normal IRP and outcomes after peroral endoscopic myotomy (POEM).
Patients with achalasia were collected in whom POEM was performed from November 2014 to April 2018 at CHA Bundang Medical Center. Achalasia with normal IRP was defined by findings compatible to achalasia in Eckardt score, endoscopy with endoscopic ultrasound, high-resolution manometry, impedance planimetry (EndoFlip), and timed esophagogram.
POEM was performed in 89 patients with achalasia; among them, 24 (27%) patients were diagnosed with achalasia with normal IRP. Patients with achalasia with normal IRP were older, had longer duration of symptom, and had a more tortuous esophagus. In EndoFlip, the distensibility index and cross-sectional area were higher in patients with normal IRP. Therapeutic outcomes showed no statistically significant differences. On correlation analysis, IRP had negative correlations with age, disease duration, and distensibility index.
Patients with achalasia of normal IRP value were older and had longer disease duration and higher distensibility index and crosssectional area than patients with achalasia with abnormal relaxation of lower esophageal sphincter. Therapeutic outcomes were not different between the 2 groups.
Keywords: Esophageal achalasia; Esophageal sphincter, lower; Myotomy

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