title: Transient lower esophageal sphincter relaxations and reflux: mechanistic analysis using concurrent fluoroscopy and high-resolution manometry.
abstract: OBJECTIVE
  The aim of this study was to perform a detailed analysis of the mechanics leading to esophagogastric junction (EGJ) opening during transient lower esophageal sphincter relaxations (tLESRs) using high-resolution manometry coupled with simultaneous fluoroscopy.
  
  
  METHODS
  Six subjects without hiatus hernia had endoclips placed at the squamocolumnar junction and 10 cm proximal. A 36-channel solid-state manometric assembly was placed spanning from stomach to pharynx, and subjects were studied for 2 hours after a high-fat meal. An esophageal pH electrode also was placed and fluoroscopy was initiated at the onset of a tLESR. Axial clip movement was measured during replay of the videotaped fluoroscopy and was correlated with manometric data.
  
  
  RESULTS
  Ninety-three tLESRs were recorded, 62 tLESRs of which had good fluoroscopic visualization. Seventy-eight tLESRs had manometric evidence of flow and the majority had evidence of a common cavity (88%), but few were detected by the pH electrode. Esophageal shortening and crural diaphragm inhibition always preceded EGJ opening and common cavity. A positive pressure gradient between the stomach and the EGJ lumen of 7.1 mm Hg (interquartile range, 4.1-9.1 mm Hg) preceded the EGJ opening.
  
  
  CONCLUSIONS
  Key events leading to the EGJ opening during tLESRs were LES relaxation, crural diaphragm inhibition, esophageal shortening, and a positive pressure gradient between the stomach and the EGJ lumen. The manometric signature of opening was pressure equalization within the EGJ, but this only occasionally was associated with pH evidence of reflux. Future investigations will need to analyze how this delicately balanced anatomic-physiologic system is perturbed in subjects with reflux disease.
authors.affiliation: Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA. j-pandolfino@northwestern.edu
authors.forename: John E
authors.initials: JE
authors.lastname: Pandolfino
authors.forename: Qing G
authors.initials: QG
authors.lastname: Zhang
authors.forename: Sudip K
authors.initials: SK
authors.lastname: Ghosh
authors.forename: Alexander
authors.initials: A
authors.lastname: Han
authors.forename: Christopher
authors.initials: C
authors.lastname: Boniquit
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kahrilas
mesh_terms: D000328:Adult; D003952:Diagnostic Imaging; D049630:Esophageal Sphincter, Lower / Q000502:physiology*; D004943:Esophagogastric Junction / Q000503:physiopathology; D005260:Female; D005471:Fluoroscopy; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008365:Manometry; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D009126:Muscle Relaxation / Q000502:physiology*; D019518:Postprandial Period