Abstract 15800: Aging is Associated With an Earlier Arrival of Reflected Waves Without a Distal Shift in Reflection Sites
Background: Despite pronounced increases in carotid-femoral pulse wave velocity (PWV) with aging, timing of the inflection point (TINF) in the central pressure waveform does not appreciably decrease. Because TINF has been interpreted as a marker of reflected wave transit time (RWTT), its dissociation from the changes in PWV led to the controversial proposition of a “distal shift” of arterial reflection sites with aging. However, TINF represents a poor surrogate of RWTT. We assessed whether aging is indeed associated with a distal shift in reflection sites when appropriate pressure-flow analyses are used.
Methods: We studied a sample of unselected adults without cardiovascular disease (n=48; median age 48 years) and a clinical population of older adults with suspected or established cardiovascular disease (n=164; 61 years). We measured central pressure and flow with carotid tonometry and phase-contrast MRI, respectively. We assessed RWTT using wave-separation analysis and partially-distributed tube-load arterial system modeling.
Results: Consistent with previous reports, TINF did not appreciably decrease with age despite pronounced increases in PWV in both populations, falsely suggesting a proximal shift in reflection sites. However, when pressure-flow analyses were applied, aging was clearly associated with pronounced decreases in RWTT by either wave separation analysis (general population:-15.0 msec/decade; P<0.001; clinical population:-9.07 msec/decade; P=0.003) or tube load modeling (general:-15.8 msec/decade; P<0.001; clinical:-11.8 msec/decade; P<0.001). There was no evidence of an increased effective reflecting distance by either method. TINF was shown to reliably represent RWTT only under highly unrealistic assumptions about human input impedance.
Conclusions: RWTT declines with age in parallel with increased PWV, with earlier arrival of wave reflections and without a distal shift in reflecting sites. Our findings disprove the proposition of a distal shift in reflection sites, which was advanced based on TINF, a poor surrogate of RWTT. These findings have important implications for our understanding of the role of the forward wave vs. reflections with aging and various disease states.
Author Disclosures: T.S. Phan: None. J.K. Li: None. P. Segers: None. M.R. Koppula: None. S.R. Akers: None. S.T. Kuna: None. T. Gislason: None. A.I. Pack: None. J.A. Chirinos: Research Grant; Significant; NIH, American College of Radiology Network, Fukuda Denshi, Bristol Myers Squibb, Microsoft and CVRx Inc. Other Research Support; Modest; Fukuda Denshi, Withings, Atcor Medical. Consultant/Advisory Board; Modest; Fukuda Denshi, Microsoft Research, Merck and Vital Labs. Consultant/Advisory Board; Significant; Bristol Myers Squibb, OPKO Healthcare.
- © 2016 by American Heart Association, Inc.