A Unique Esophageal Motor Pattern That Involves Longitudinal Muscles Is Responsible for Emptying in Achalasia Esophagus

BACKGROUND & AIMS: Achalasia esophagus is characterized by loss of peristalsis and incomplete esophagogastric junction (EGJ) relaxation. We studied mechanisms of esophageal emptying in patients with achalasia using simultaneous high-resolution manometry, multiple intraluminal impedance, and high-frequency intraluminal ultrasonography image recordings. METHODS: Achalasia was categorized into 3 subtypes, based on the esophageal response to swallows: types 1 and 2 were defined by simultaneous pressure waves of <30 mm Hg and >30 mm Hg, respectively, and type 3 was defined by spastic simultaneous esophageal contractions. RESULTS: Based on high-resolution manometry, 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), and EGJ contraction following swallows. High-frequency intraluminal ultrasonography identified longitudinal muscle contraction of the distal esophagus as the cause of pan-esophageal pressurization in type 2 achalasia. Multiple intraluminal impedance revealed that esophageal emptying occurred intermittently (36% swallows) during periods of pan-esophageal pressurization. Patients with achalasia of types 1 and 3 had no emptying or relatively normal emptying during most swallows, respectively. CONCLUSIONS: In achalasia, esophageal emptying results from swallow-induced longitudinal muscle contraction of the distal esophagus, which increases esophageal pressure and allows flow across the nonrelaxed EGJ.