title: Characteristics of the esophageal low-pressure zone in healthy volunteers and patients with esophageal symptoms: assessment by high-resolution manometry.
abstract: BACKGROUND
  Esophageal motility studies in humans have documented a low-pressure zone (LPZ) in the area of transition from striated to smooth muscle. While preliminary studies indicate that a bolus might be retained in this area, the clinical relevance of the LPZ remains unclear.
  
  
  OBJECTIVE
  To investigate a possible relationship between esophageal symptoms and the size of the esophageal LPZ.
  
  
  METHODS
  We reviewed high-resolution manometry (HRM) data from patients with esophageal symptoms (dysphagia, chest pain, and heartburn/regurgitation) and asymptomatic volunteers. The proximal border of the LPZ was defined as the point where the amplitude of the proximal contraction wave declined below 30 mmHg, and the distal border as the point where the distal contraction wave first increased above 30 mmHg.
  
  
  RESULTS
  The average (+/- standard error of mean [SEM]) length of the LPZ in 44 asymptomatic individuals was 5.4 +/- 0.6 cm and did not differ (P= 0.222) from the LPZ in 64 patients with dysphagia (6.8 +/- 0.4 cm), 34 patients with chest pain (6.4 +/- 0.6 cm), and 42 patients with gastroesophageal reflux disease (GERD) symptoms (7.0 +/- 0.6 cm). These results did not change when the length of the LPZ was corrected for total esophageal length. The time width of the LPZ in asymptomatic individuals (1.6 +/- 0.2 s) was shorter than in patients with dysphagia and GERD symptoms (dysphagia 2.4 +/- 0.2 s, GERD symptoms 2.8 +/- 0.3 s).
  
  
  CONCLUSIONS
  A time delay between the proximal and distal esophageal contraction waves might be a meaningful variable in GERD and dysphagia.
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pohl
authors.forename: Mentore
authors.initials: M
authors.lastname: Ribolsi
authors.forename: Edoardo
authors.initials: E
authors.lastname: Savarino
authors.forename: Heiko
authors.initials: H
authors.lastname: Frühauf
authors.forename: Michael
authors.initials: M
authors.lastname: Fried
authors.forename: Donald O
authors.initials: DO
authors.lastname: Castell
authors.forename: Radu
authors.initials: R
authors.lastname: Tutuian
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004935:Esophageal Diseases / Q000503:physiopathology*; D004947:Esophagus / Q000503:physiopathology*; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology*; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D011312:Pressure; D011379:Prognosis; D012189:Retrospective Studies