Esophageal Motility Testing: The Present and the Future

Abstract

Motor function can be assessed by a variety of recording techniques including radiology, scintigraphy manometry, and most recently intraluminal electrical impedance monitoring. The gold standard, however, for the assessment of motor disorders remains manometry. Since its introduction in the early 1950s, esophageal manometry has contributed to a better understanding of esophageal motor function and has currently become a widely performed technique in clinical practice. In the last 10 years, a new system to perform esophageal manometry was developed and introduced in both research and clinical setting: the high-resolution manometry. It utilizes closely spaced pressure sensors to create a dynamic representation of pressure change along the entire length of the esophagus. Along with the technological innovation, an international consensus process has evolved over recent years to define esophageal motility disorders using HRM, Clouse plots, and standardized metrics. This classification, titled the Chicago Classification (CC), was firstly published in 2009 and updated in 2012 and in 2015 (v3.0). The key metrics of interpretation applied for the CC v3.0 are the integrated relaxation pressure (IRP), the distal contractile integral (DCI), and the distal latency (DL). In its last iteration, the CC utilizes a hierarchical approach, sequentially prioritizing (i) disorders of esophagogastric junction (EGJ) outflow (achalasia subtypes I–III and EGJ outflow obstruction), (ii) major disorders of peristalsis (absent contractility, distal esophageal spasm, hypercontractile esophagus), and (iii) minor disorders of peristalsis characterized by impaired bolus transit (“fragmented” contractions in case of large breaks in the 20-mmHg isobaric contour, ineffective esophageal motility). EGJ morphology, characterized by the degree of overlap between the lower esophageal sphincter and the crural diaphragm, and baseline EGJ contractility are also part of CC v3.0. Future developments of CC will include pharyngeal and UES functions, combined impedance measurements to assess the bolus flow, and swallow challenges to trigger motility abnormalities. In summary, the CC is an evolving process and much remains to be elucidated in the next versions.