Background/aims: We aim to investigate the diagnostic accuracy and differences between Chicago classification version 3.0 (CC v3.0) and 4.0 (CC v4.0).
Methods: Patients who underwent high-resolution esophageal manometry (HRM) for suspected esophageal motility disorders were prospectively recruited between May 2020 and February 2021. The protocol of HRM studies included additional positional change and provocative testing designed by CC v4.0.
Results: Two hundred forty-four patients were included. The median age was 59 (interquartile range, 45-66) years, and 46.7% were males. Of these, 53.3% (n = 130) and 61.9% (n = 151) were categorized as normalcy by CC v3.0 and CC v4.0, respectively. The 15 patients diagnosed of esophagogastric junction outflow obstruction (EGJOO) by CC v3.0 was changed to normalcy by position (n = 2) and symptom (n = 13) by CC v4.0. In seven patients, the ineffective esophageal motility (IEM) diagnosis by CC v3.0 was changed to normalcy by CC v4.0. The diagnostic rate of achalasia increased from 11.1% (n = 27) to 13.9% (n = 34) by CC v4.0. Of patients diagnosed IEM by CC v3.0, 4 was changed to achalasia based on the functional lumen imaging probe (FLIP) results by CC v4.0. Three patients (2 with absent contractility and 1 with IEM in CC v3.0) were newly diagnosed with achalasia using a provocative test and barium esophagography by CC v4.0.
Conclusions: CC v4.0 is more rigorous than CC v3.0 for the diagnosis of EGJOO and IEM and diagnoses achalasia more accurately by using provocative tests and FLIP. Further studies on the treatment outcomes following diagnosis with CC v4.0 are needed.
Keywords: Achalasia; Chicago classification; Esophagogastric junction outflow obstruction; High-resolution manometry; Ineffective esophageal motility.