Characteristics of esophageal proper muscle in patients with non‐cardiac chest pain using high‐frequency intraluminal ultrasound

Abstract

It is unclear which mechanisms play a predominant role in the pathogenesis of esophageal non-cardiac chest pain (NCCP). We aimed to examine the features of esophageal proper muscle and esophageal contractility using a high-frequency intraluminal ultrasound (HFIUS) in patients with NCCP. A total of 68 patients with NCCP were classified into two groups according to the results of typical reflux symptoms and/or esophagogastroduodenoscopy and/or 24-h esophageal pH monitoring: gastroesophageal reflux disease (GERD)-positive NCCP (n = 34) and GERD-negative NCCP groups (n = 34). Additionally 16 asymptomatic healthy subjects were included as controls. Using HFIUS, we analyzed the esophageal proper muscle thickness and cross-sectional area (CSA) at 3 cm above lower esophageal sphincter (LES) and 9 cm above LES during baseline rest and peak contraction periods among the control, GERD-positive NCCP and GERD-negative NCCP groups, and examined the completeness of three phases of esophageal action during five wet swallows in the three groups. The muscle thickness and CSA tended to be larger in GERD-negative NCCP than in GERD-positive NCCP and in control groups at esophageal body during both periods. All of the controls and patients with GERD-positive NCCP presented the complete peristaltic type. Whereas, 11 of 34 patients with GERD-negative NCCP presented the incomplete peristaltic type. Using HFIUS, patients with GERD-negative NCCP had increased muscle thickness and CSA. Some GERD-negative NCCP had the incomplete peristaltic type.