Chicago classification of high-resolution esophageal manometry: Is old the gold or is new better?

Abstract

High-resolution manometry (HRM), a landmark concept in gastrointestinal motility study, was introduced in the early 1990s by Clouse and Staiano [1]. In this new technology, pressure profile is assessed during several liquid and viscous swallows using a catheter having a large number of ports at closely spaced positions in the esophagus [2]. Time, catheter position, and average pressure are then reconstructed into pseudo-3D "topographic plots" that demonstrated the functional anatomy of the esophagus and that of the gastroesophageal junction taking gastric pressure as the baseline [2].There are several advantages of HRM over conventional manometry [2][3][4][5][6][7]. The advantages may be broadly classified into two groups, (a) those related to the recording of the data and (b) those related to the display of the data. The advantages of HRM over conventional manometry with respect to the data recording include (a) higher number of sensors that record lumen-occlusive contractions of the circular muscle of esophagus (typically six to eight ports in the earlier conventional manometry in contrast to 32 ports in current HRM), (b) use of solid-state catheter with higher fidelity in place of water-perfusion catheters, (c) use of circumferential in place of non-circumferential sensors, (d) facility to evaluate bolus transport by impedance monitoring that is available in most of the standard HRM devises, and (e) HRM is easier to perform than the conventional manometry. Display of the complex data using Clouse plot is a major advantage of HRM over conventional manometry. In the conventional manometry, the horizontal (X) axis depicts the time and the vertical (Y) axis represents the amplitude of contraction. In the Clouse plot of HRM, the horizontal (X) axis depicts the time, but the vertical (Y) axis represents the length of the esophagus. How to depict the amplitude of contraction then? Ray E Clouse decided to use different colors to represent the amplitude of contraction, the deep blue being the most negative pressure, and black showing highest positive pressure. Conventional manometry may miss esophageal motility disorders causing dysphagia. In a study on 250 patients with motor dysphagia, the cause could not be identified by conventional manometry in 15 % patients [8]. This might be due to widely spaced sensors in the catheter. Due to large number of sensors, HRM is expected to have higher fidelity to diagnose esophageal motility disorders, which has been documented in the literature [9]. One of the many advantages of the Clouse plot in HRM is the ease with which different esophageal motility disorders can be grossly recognized by the experienced motility doctors, but in the era of super-speciality health care using evidenced-based medicine and various mathematical scoring systems, are the doctors and patients happy with gross recognition of disorders?Chicago classification system has been developed by consensus among a group of motility experts based on the available evidence and general principles of esophageal physi...