title: Susceptibility to dysphagia after fundoplication revealed by novel automated impedance manometry analysis.
abstract: BACKGROUND
  Conventional measures of esophageal pressures or bolus transport fail to identify patients at risk of dysphagia after laparoscopic fundoplication.
  
  
  METHODS
  Liquid and viscous swallows were evaluated with impedance/manometry in 19 patients with reflux disease before and after surgery. A new method of automated impedance manometry (AIM) analysis correlated esophageal pressure with impedance data and automatically calculated a range of pressure and bolus movement variables. An iterative analysis determined whether any variables were altered in relation to dysphagia. Standard measures of esophago-gastric junction pressure, bolus presence time, and total bolus transit time were also evaluated.
  
  
  RESULTS
  At 5 months postop, 15 patients reported some dysphagia, including 7 with new-onset dysphagia. For viscous boluses, three AIM-derived pressure-flow variables recorded preoperatively varied significantly in relation to postoperative dysphagia. These were: time from nadir esophageal impedance to peak esophageal pressure (TNadImp-PeakP), median intra-bolus pressure (IBP, mmHg), and the rate of bolus pressure rise (IBP slope, mmHgs(-1) ). These variables were combined to form a dysphagia risk index (DRI=IBP×IBP_slope/TNadImp-PeakP). DRI values derived from preoperative measurements were significantly elevated in those with postoperative dysphagia (DRI=58, IQR=21-408 vs no dysphagia DRI=9, IQR=2-19, P<0.02). A DRI >14 was optimally predictive of dysphagia (sensitivity 75% and specificity 93%).
  
  
  CONCLUSIONS
  Before surgery, a greater and faster compression of a swallowed viscous bolus with less bolus flow time relates to postoperative dysphagia. Thus, susceptibility to postfundoplication dysphagia is related to a pre-existing sub-clinical variation of esophageal function.
authors.affiliation: Discipline of Surgery, University of Adelaide, Royal Adelaide Hospital, Adelaide, SA, Australia.
authors.forename: J C
authors.initials: JC
authors.lastname: Myers
authors.forename: N Q
authors.initials: NQ
authors.lastname: Nguyen
authors.forename: G G
authors.initials: GG
authors.lastname: Jamieson
authors.forename: J E
authors.initials: JE
authors.lastname: Van't Hek
authors.forename: K
authors.initials: K
authors.lastname: Ching
authors.forename: R H
authors.initials: RH
authors.lastname: Holloway
authors.forename: J
authors.initials: J
authors.lastname: Dent
authors.forename: T I
authors.initials: TI
authors.lastname: Omari
mesh_terms: D000328:Adult; D000368:Aged; D003680:Deglutition Disorders / Q000209:etiology* / Q000503:physiopathology; D017097:Electric Impedance; D001330:Electronic Data Processing; D004943:Esophagogastric Junction / Q000503:physiopathology; D004947:Esophagus / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D018662:Fundoplication / Q000009:adverse effects*; D005764:Gastroesophageal Reflux / Q000601:surgery; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D012307:Risk Factors; D012680:Sensitivity and Specificity