The vascular impact of aging andvasoactive drugs: comparison of twodigital volume pulse measurements

Abstract Background Indices of pressure wave reflection (RIDVP) and large artery stiffness (SIDVP) can be derived from the digital volume pulse (DVP). Indices obtained from the second derivative of the DVP have also been proposed to characterize vascular aging and effects of vasoactive drugs. Methods We compared RIDVP and SIDVP with the indices a/b, a/c, a/d, and a/e calculated from sequential peaks of the second derivative of the DVP in 124 healthy men. The DVP was obtained by measuring infrared light transmission through the finger. In 10 men measurements were obtained at baseline and during intravenous infusion of glyceryl trinitrate (GTN, 3 to 300 μg/min) and, on separate occasions, angiotensin II (AII, 75 to 300 μg/min) and saline vehicle. Results SIDVP was strongly associated with age (R = 0.63, P< .001) but little influenced by AII or GTN. RIDVP was weakly associated with age but showed a consistent dose-dependent increase during AII and a decrease during GTN. d/a was strongly associated with age (R = −0.66, P< .001), influenced by vasoactive drugs but did not change in a dose-dependent manner during GTN. Other second derivative indices were less strongly correlated with age and showed an inconsistent response to vasoactive drugs. Within subject standard deviations of SIDVP and d/a for measurements on different occasions were 2.1 and 5.4 “years of vascular aging” respectively. Conclusions In healthy men, RIDVP may be a more reliable index of the effects of vasoactive drugs than d/a. SIDVP is similarly associated with age as is d/a, but less variable and may thus be a better index of vascular aging.