Background: The values of the parameters in the Chicago classification measured by a high-resolution manometry (HRM) system with the Unisensor catheter (Starlet) are significantly different from those measured by the ManoScan. The contraction vigor is categorized by values of the distal contractile integral (DCI) in the Chicago classification v3.0; however, reference values of the DCI in the Starlet and the clinical impact of the different reference values in the Starlet and ManoScan on diagnosing esophageal motility disorders are not known.
Methods: We evaluated data from a previous report in which ManoScan and Starlet were compared in the same subjects. The DCI values in each system were compared and reference DCI values were calculated. Moreover, diagnoses assessed by Starlet using reference values in ManoScan were compared with those using calculated reference values and those assessed by ManoScan.
Results: There was a significant positive correlation between the DCI values measured by ManoScan and those measured by Starlet (r = 0.80, p < 0.01). Based on a linear functional relationship considering measurement errors, the reference DCI values for diagnosing failed, weak and hypercontractile contraction vigor were calculated as 590.6, 1011.3 and 10,085.8 mmHg-s-cm, respectively, in the Starlet. Therefore, the proposed reference values in the Starlet were 500, 1000 and 10,000 mmHg-s-cm, respectively. When the reference values in the ManoScan were used in the Starlet data, approximately 30% of subjects were diagnosed inappropriately. This issue was resolved using the proposed reference values in the Starlet.
Conclusion: Recognizing systemic differences in HRM systems is important.
Keywords: Chicago classification; High-resolution manometry; ManoScan; Reference values; Starlet.