Expert consensus document: Advances in the management of oesophageal motility disorders in the era of high-resolution manometry: a focus on achalasia syndromes.

High-resolution manometry (HRM) and new analysis algorithms, summarized in the Chicago Classification, have led to a restructured classification of oesophageal motility disorders. This advance has led to increased detection of clinically relevant disorders, in particular achalasia. It has become apparent that the cardinal feature of achalasia - impaired lower oesophageal sphincter (LES) relaxation - can occur in several disease phenotypes: without peristalsis (type I), with pan-oesophageal pressurization (type II), with premature (spastic) distal oesophageal contractions (type III), or with preserved peristalsis (outlet obstruction). Furthermore, no manometric pattern is perfectly sensitive or specific for achalasia caused by a myenteric plexopathy, and there is no biomarker for this pathology. Consequently, physiological testing reveals other syndromes not meeting achalasia criteria that also benefit from therapies formerly reserved for achalasia. These findings have become particularly relevant with the development of a minimally invasive technique for performing a long oesophageal myotomy, the per-oral endoscopic myotomy (POEM). Optimal management is to render treatment in a phenotype-specific manner; that is, POEM calibrated to patient-specific physiology for spastic achalasia and the spastic disorders, and more conservative strategies such as pneumatic dilation for the disorders limited to the LES. This Consensus Statement examines the effect of HRM on our understanding of oesophageal motility disorders, with a focus on the diagnosis, epidemiology and management of achalasia and achalasia-like syndromes.