title: Post-exercise ankle-brachial pressure index demonstrates altered endothelial function in the elderly.
abstract: BACKGROUND
  The ankle-brachial pressure index (ABI), the ratio of the systolic blood pressure of the ankle to the systolic brachial pressure, is commonly measured at rest, but ABI values post-exercise enhance the sensitivity of the test and can be used to identify atherosclerotic vascular damage. However, it has not been established whether or not enhanced post-exercise ABI is also associated with endothelial dysfunction. We hypothesized that a decrease in post-exercise ABI is related to impaired endothelial function.
  
  
  OBJECTIVE
  To investigate alterations in post-exercise ABI values and endothelial dysfunction in the elderly.
  
  
  METHODS
  The study population comprised 35 men and women aged 51-77 years (mean age: 66 years). Patients with peripheral arterial disease or a history of heart failure were excluded. The ABI was estimated at rest and immediately after exercise. The exercise protocol comprised 2.5 min of active pedal flexion exercises at a speed of 60 times/min. Endothelial function was assessed by measuring flow-mediated vasodilation (FMD) in the brachial artery using ultrasound imaging.
  
  
  RESULTS
  No correlation was found between FMD and the ABI at rest. However, a weak correlation was found between FMD and post-exercise ABI (r = 0.46, P = 0.06). A strong correlation was observed between FMD and a decrease in post-exercise ABI compared to baseline readings (r = -0.52, P = 0.01). Multiple linear regression analysis was used to generate a prediction equation for FMD using the percentage decrease in post-exercise ABI. Significant correlations were observed between the ultrasound imaging-measured FMD and the predicted FMD (R(2) = 0.27, P = 0.001).
  
  
  CONCLUSIONS
  Post-exercise ABI appears to be a simple surrogate marker for endothelial function in the elderly, although larger studies are required for validation.
authors.affiliation: Department of Sport and Health Science, Osaka Sangyo University, Osaka, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Sato
authors.forename: Kozue
authors.initials: K
authors.lastname: Masami
authors.forename: Shingo
authors.initials: S
authors.lastname: Otsuki
authors.forename: Shiro
authors.initials: S
authors.lastname: Tanaka
authors.forename: Noriko
authors.initials: N
authors.lastname: Nakayama
authors.forename: Shigeru
authors.initials: S
authors.lastname: Makita
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Koshiyama
authors.forename: Ryuji
authors.initials: R
authors.lastname: Nohara
keywords: ABI; FMD; elder; endothelial function; exercise