title: Jackhammer esophagus: Observations on a European cohort.
abstract: BACKGROUND
  With the advent of high-resolution manometry (HRM), a new diagnosis, jackhammer esophagus, was introduced. Little is known about this rare condition, and the relationship between symptoms and hypercontractility is not always straightforward. The aim of our study was to describe a large cohort of patients with jackhammer esophagus and to investigate whether manometric findings are associated with the presence of symptoms.
  
  
  METHODS
  All patients from 06, 2014 until 12, 2015 seen at two tertiary centers with at least one hypercontractile swallow (distal contractile integral [DCI] >8000 mm Hg/s/cm) on HRM were analyzed. Patients with ≥20% premature swallows, or patients with another diagnosis explaining their symptoms were excluded.
  
  
  RESULTS
  Of the 34 patients identified with jackhammer esophagus, most suffered from dysphagia (67.6%) and/or chest pain (47.1%). The symptom chest pain was not associated with any of the manometric findings, whereas dysphagia was associated with the DCI of the hypercontractile swallows and with intrabolus pressure. In addition, all patients who had an isolated DCI of the lower esophageal sphincter (LES) zone >2000 mm Hg/s/cm had dysphagia. The differences in HRM and clinical characteristics between subgroups based on the contraction type (single- or multi-peaked) or based on meeting criteria of the Chicago Classification v3.0 and v2.0 were limited.
  
  
  CONCLUSIONS
  The symptom dysphagia is accompanied with strong contractions of the LES, signs of a possible outflow obstruction, and a very high DCI. The presence of a multipeaked contraction seems to be of limited relevance, and caution is warranted in labeling patients with one hypercontractile swallow as normal.
authors.affiliation: Department of Gastroenterology and Hepatology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: T V K
authors.initials: TV
authors.lastname: Herregods
authors.affiliation: Department of Gastroenterology and Hepatology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: A J P M
authors.initials: AJ
authors.lastname: Smout
authors.affiliation: Barts and the London School of Medicine, Queen Mary University of London, London, UK.
authors.forename: J L S
authors.initials: JL
authors.lastname: Ooi
authors.affiliation: Barts and the London School of Medicine, Queen Mary University of London, London, UK.
authors.forename: D
authors.initials: D
authors.lastname: Sifrim
authors.affiliation: Department of Gastroenterology and Hepatology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: Bredenoord
mesh_terms: D002637:Chest Pain / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D015331:Cohort Studies; D003680:Deglutition Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D015154:Esophageal Motility Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology*; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods; D008875:Middle Aged
keywords: Jackhammer esophagus; chest pain; dysphagia; hypercontractile esophagus; manometry