Although it will take years for an HRM consensus for a classification system to mature fully, substantial progress has occurred in the process of only a few years. At least with respect to the distal oesophagus, Tables and represent a reasonable representation of this. details the vital measures to be made on individual swallows in an HROPT study. As described in the text, this results in ascertaining normal or abnormal OGJ relaxation, OGJ morphology, distal segment wavefront propagation velocity, hypotensive peristalsis, peristaltic vigour, and specific patterns of IBP. All of these measures can now be made with analysis tools available in the current version of ManoView™ analysis software (version 2.1; Sierra Scientific Instruments Inc.) and Solar GI HRM (Medical Measurement Systems).
Following analysis of individual swallows by the criteria in , the component results are synthesized into a global diagnosis by the criteria detailed in . Patients with normal OGJ relaxation, normal CFV, and a DCI <5000 mmHg s−1
are reported as normal while the range of potential abnormalities is then detailed. Note that, in contrast to conventional classification schemes, there is no category of non-specific oesophageal motility disorders. This is intentional, as all manometric findings are non-specific; manometry only describes oesophageal contractility or pressurization patterns and there is always more than one diagnosis associated with a particular pattern.13,19
Even the most specific pattern, classic achalasia, can be seen as a result of either mechanical outflow obstruction or idiopathic achalasia. Hence, the abnormalities encountered are described in specific functional terms with the intent that these then be interpreted within the clinical context of the patient. An example of that strategy was the description of OGJ obstruction as the combination of impaired deglutitive OGJ relaxation and/or elevated IBP in the context of some preserved peristalsis (). This has several potential aetiologies including mechanical obstruction (eg. Fundoplication, para-oesophageal hernia, tumour), variant achalasia, and oeosinophilic oesophagitis. In addition, functional obstruction could be related to a hiatus hernia and can be subtyped based on the location of the obstruction (LOS or CD).
As alluded to in the introduction, HROPT classification of oesophageal motor function will require continuous refinement of diagnostic criteria. At this point, the emphasis of the endeavour is to establish a useful framework both to guide the clinical management of oesophageal motility disorders and to highlight areas of uncertainty where research opportunities exist. A brief inventory of unresolved issues to be taken up in future includes: the sub-classification of hypotensive peristalsis (likely based on outcome data and/or impedance correlations), the sub-categorization of DOS, consideration of OGJ morphologic subtypes in functional OGJ obstruction, defining transition zone defects, defining proximal oesophageal segment defects, and defining upper oesophageal sphincter dysfunction. By adopting an evidence-based strategy and focusing on methodological soundness, accurate diagnostic criteria, and outcome studies, it is hoped that this effort will enhance the value of clinical manometry as a tool for the diagnosis and management of oesophageal diseases.