Biological aortic age derived from the arterial pressure waveform

Abstract

Shibata S, Levine BD. Biological aortic age derived from the arterial pressure waveform. J Appl Physiol 110: 981-987, 2011. First published February 3, 2011 doi:10.1152/japplphysiol.01261.2010.-Indexes for arterial stiffness are, by their nature, influenced by the ambient blood pressure due to the curvilinear nature of arterial compliance. We developed a new concept of the "Modelflow aortic age," which is, theoretically, not influenced by the ambient blood pressure and provides an easily understood context (biological vs. chronological age) for measures of arterial stiffness. The purpose of the present study was to validate this pressure-independent index for aortic stiffness in humans. Twelve sedentary elderly (65-77 yr), 11 Masters athletes (65-73 yr), and 12 sedentary young individuals (20 -42 yr) were studied. Modelflow aortic ages were comparable with chronological ages in both sedentary groups, indicating that healthy sedentary individuals have age-appropriate aortas. In contrast, Masters athletes showed younger Modelflow aortic ages than their chronological ages. The coefficient of variation of sedentary subjects was three times smaller with the Modelflow aortic age (21%) than with other indexes, such as static systemic arterial stiffness (61%), central pulse wave velocity (61%), or carotid ␤-stiffness index (58%). The typical error was very small and two times smaller in the Modelflow aortic age (Ͻ7%) than in static systemic arterial stiffness (Ͼ13%) during cardiac unloading by lower body negative pressure. The Modelflow aortic age can more precisely and reliably estimate aortic stiffening with aging and modifiers, such as life-long exercise training compared with the pressure-dependent index of static systemic arterial stiffness, and provides a physiologically relevant and clinically compelling context for such measurements. arterial stiffness; aging; Modelflow ARTERIOSCLEROSIS WITH AGING leads to large-vessel arterial stiffening in humans. This process is characterized primarily by the development of fibrosis and degeneration of elastin, which result in structural changes in the arterial wall (28, 29). Indeed, work by Langewouters et al. (30, 31) and Wesseling et al. (49) showed that structural properties of the thoracic and abdominal aortas are altered linearly with age in humans and are clinically relevant. Large arterial stiffness is an independent predictor of mortality and morbidity from cardiovascular disease in the elderly population (3,4,7,11,33,37,39,44,50).Central aortic stiffness can be evaluated by several methods, such as pulse-wave velocity (PWV) of the central aorta, systemic arterial compliance (ratio of stroke volume to pulse pressure), or aortic impedance (dynamic relationship between aortic flow and pressure) (34, 41). However, all of these approaches are, by their nature, influenced by the ambient blood pressure due to the curvilinear nature of arterial compliance (arterial pressure-area relationship) (38). For example, higher blood pressures shift the operational point of the ar...

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“…For example, we developed a technique that can quantify the biological age of the aorta and applied it to this same group of Masters athletes and controls. 29 As expected, both the healthy,…”

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“…Therefore, this index for biologic aortic age is most likely to represent structural changes of the central arterial walls with little influence by functional factors (37). The present finding that the Modelflow aortic age did not change even after 1 yr of endurance exercise training suggests that structural changes in the arterial wall such as degeneration of elastin and development of fibrosis with aging are not reversible by endurance exercise training alone in the previously sedentary healthy elderly.…”

“…The Modelflow aortic age was analyzed as described previously (37). First, Modelflow stroke volumes were generated from a given central blood pressure waveform reconstructed from the finger blood pressure waveform (Beatscope 1.1a; FMS) by using input ages to the Modelflow system from 20 to 90 yr (17,45).…”

Aortic pulse wave velocity and reflecting distance estimation from peripheral waveforms in humans: detection of age- and exercise training-related differences

“…In an additional cohort of subjects (validation cohort), we tested the hypotheses that 1) the EfRD estimated from demographic/anthropometric parameters can reliably detect the distal shift of the reflecting site with aging (i.e., longer EfRD in older subjects) (9,24,36) and 2) APWV derived from peripheral pressure waveforms detects the well known increase in CFPWV with sedentary aging in humans that is attenuated in older adults who perform habitual endurance exercise training (7,11,23,29,31).…”