A Unique Esophageal Motor Pattern That Involves Longitudinal Muscles Is Responsible for Emptying in Achalasia Esophagus (Gastroenterology 2010;139:102-111)

Abstract

Hong et al1 has reported a study entitled A unique esophageal motor pattern that involves longitudinal muscles is responsible for emptying in achalasia in the July 2010 issue of Gastroenterology. Achalasia esophagus is characterized by loss of peristalsis and incomplete esophagogastric junction (EGJ) relaxation. Recent studies showed that there is considerable heterogeneity in the disease entity of achalasia esophagus.2 The symptoms such as dysphagia and chest pain in achalasia patients are related to poor esophageal emptying, and in turn related to impaired lower esophageal sphincter (LES) relaxation and lack of esophageal peristalsis. In achalasia, even though incomplete, esophageal emptying occurs intermittently, irrespective of the gravity. However, the precise mechanism of esophageal emptying has never been studied. In this study, based on a recent high-resolution manometry (HRM) classification proposed by Pandolfino et al,3 achalasia was categorized into 3 subtypes based on the esophageal response to wet swallows: type 1 was defined by simultaneous pressure waves of 30 mmHg and type 3 was defined by spastic simultaneous contractions. The authors evaluated the mechanisms of esophageal emptying in 13 patients with achalasia using simultaneous HRM, multiple intraluminal impedance (MII) and high-frequency intraluminal ultrasonography (HFIUS) images. In the results, based on HRM, the predominant achalasia pattern of type 2 was characterized by a unique motor pattern that consisted of upper esophageal sphincter contraction, simultaneous esophageal pressure (pan-esophageal pressurization [PEP]) and EGJ contraction following wet swallows. HFIUS identified longitudinal muscle contraction of the distal esophagus as the cause of PEP in type 2 achalasia. MII revealed that esophageal emptying occurred intermittently (36% swallows) during the periods of PEP. On the other hand, type 1 achalasia had no emptying and type 3 achalasia had relatively normal emptying during most swallows. Therefore, they concluded that the esophageal emptying in achalasia results from swallow-induced longitudinal muscle contraction of the distal esophagus, which increases esophageal pressure and allows flow across the unrelaxed EGJ.