title: Aortic pulse wave velocity and reflecting distance estimation from peripheral waveforms in humans: detection of age- and exercise training-related differences.
abstract: We hypothesized that demographic/anthropometric parameters can be used to estimate effective reflecting distance (EfRD), required to derive aortic pulse wave velocity (APWV), a prognostic marker of cardiovascular risk, from peripheral waveforms and that such estimates can discriminate differences in APWV and EfRD with aging and habitual endurance exercise in healthy adults. Ascending aortic pressure waveforms were derived from peripheral waveforms (brachial artery pressure, n = 25; and finger volume pulse, n = 15) via a transfer function and then used to determine the time delay between forward- and backward-traveling waves (Δtf-b). True EfRDs were computed as directly measured carotid-femoral pulse wave velocity (CFPWV) × 1/2Δtf-b and then used in regression analysis to establish an equation for EfRD based on demographic/anthropometric data (EfRD = 0.173·age + 0.661·BMI + 34.548 cm, where BMI is body mass index). We found good agreement between true and estimated APWV (Pearson's R² = 0.43; intraclass correlation = 0.64; both P < 0.05) and EfRD (R² = 0.24; intraclass correlation = 0.40; both P < 0.05). In young sedentary (22 ± 2 years, n = 6), older sedentary (62 ± 1 years, n = 24), and older endurance-trained (61 ± 2 years, n = 14) subjects, EfRD (from demographic/anthropometric parameters), APWV, and 1/2Δtf-b (from brachial artery pressure waveforms) were 52.0 ± 0.5, 61.8 ± 0.4, and 60.6 ± 0.5 cm; 6.4 ± 0.3, 9.6 ± 0.2, and 8.1 ± 0.2 m/s; and 82 ± 3, 65 ± 1 and 76 ± 2 ms (all P < 0.05), respectively. Our results demonstrate that APWV derived from peripheral waveforms using age and BMI to estimate EfRD correlates with CFPWV in healthy adults. This method can reliably detect the distal shift of the reflecting site with age and the increase in APWV with sedentary aging that is attenuated with habitual endurance exercise.
authors.affiliation: Department of Health and Human Physiology, The University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Gary L
authors.initials: GL
authors.lastname: Pierce
authors.forename: Darren P
authors.initials: DP
authors.lastname: Casey
authors.forename: Jess G
authors.initials: JG
authors.lastname: Fiedorowicz
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Seals
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Curry
authors.forename: Jill N
authors.initials: JN
authors.lastname: Barnes
authors.forename: DeMaris R
authors.initials: DR
authors.lastname: Wilson
authors.forename: Harald M
authors.initials: HM
authors.lastname: Stauss
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001011:Aorta / Q000502:physiology*; D015992:Body Mass Index; D001916:Brachial Artery / Q000502:physiology; D002339:Carotid Arteries / Q000502:physiology; D015444:Exercise; D005260:Female; D005263:Femoral Artery / Q000502:physiology; D005385:Fingers / Q000098:blood supply; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance; D063177:Pulse Wave Analysis; D057185:Sedentary Behavior
keywords: aortic stiffness; blood pressure; finger volume pulse; transfer function