title: Relationship of flow-mediated arterial dilation and exercise capacity in older patients with heart failure and preserved ejection fraction.
abstract: BACKGROUND
  Older heart failure patients with preserved ejection fraction (HFpEF) have severely reduced exercise capacity and quality of life. Both brachial artery flow-mediated dilation (FMD) and peak exercise oxygen uptake (peak VO(2)) decline with normal aging. However, uncertainty remains regarding whether FMD is reduced beyond the degree associated with normal aging and if this contributes to reduced peak VO(2) in elderly HFpEF patients.
  
  
  METHODS
  Sixty-six older (70 ± 7 years) HFpEF patients and 47 healthy participants (16 young, 25 ± 3 years, and 31 older, 70 ± 6 years) were studied. Brachial artery diameter was measured before and after cuff occlusion using high-resolution ultrasound. Peak VO(2) was measured using expired gas analysis during upright cycle exercise.
  
  
  RESULTS
  Peak VO(2) was severely reduced in older HFpEF patients compared with age-matched healthy participants (15.2 ± 0.5 vs 19.6 ± 0.6 mL/kg/min, p < .0001), and in both groups, peak VO(2) was reduced compared with young healthy controls (28.5 ± 0.8 mL/kg/min; both p < .0001). Compared with healthy young participants, brachial artery FMD (healthy young, 6.13% ± 0.53%) was significantly reduced in healthy older participants (4.0 ± 0.38; p < .0002) and in HFpEF patients (3.64% ± 0.28%; p < .0001). However, FMD was not different in HFpEF patients compared with healthy older participants (p = .86). Although brachial artery FMD was modestly related to peak VO(2) in univariate analyses (r = .19; p = .048), it was not related in multivariate analyses that accounted for age, gender, and body size.
  
  
  CONCLUSIONS
  These results suggest that endothelial dysfunction may not be a significant independent contributor to the severely reduced exercise capacity in elderly HFpEF patients.
authors.affiliation: Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Haykowsky
authors.forename: David M
authors.initials: DM
authors.lastname: Herrington
authors.forename: Peter H
authors.initials: PH
authors.lastname: Brubaker
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Morgan
authors.forename: W Gregory
authors.initials: WG
authors.lastname: Hundley
authors.forename: Dalane W
authors.initials: DW
authors.lastname: Kitzman
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000473:pathology / Q000502:physiology*; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D016022:Case-Control Studies; D004108:Dilatation, Pathologic; D004730:Endothelium, Vascular / Q000503:physiopathology; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D013318:Stroke Volume; D014463:Ultrasonography; D055815:Young Adult