Validity of pulse pressure and augmentation index as surrogate measures of arterial stiffness during beta-adrenergic stimulation

Objective Increased arterial stiffness is a determinant of cardiovascular mortality. Pulse wave velocity (PWV) is a direct measure of arterial stiffness. Aortic augmentation index (All) and pulse pressure (PP) are surrogate of arterial stiffness. Both PWV, Al and PP increase with cardiovascular risk factors. The aim of this study was to test the validity of Al and PP as surrogate measures of arterial stiffness compared with PWV, during beta-adrenergic stimulation with Isoprenaline (Iso). Design and methods A total of 41 healthy volunteers entered a randomized, double-blind, placebo-controlled, cross-over study. In random order, subjects were given intravenous infusion in equal volume of Iso 8 pg/kg per min (dissolved in glucose 5%) and placebo (glucose 5%). A wash-out period of 25 min was observed between the infusions. Measurements included blood pressure (BP), heart rate (HR), PWV, and Al. PWV were determined using complior (Complior, Artech-Medical, Paris, France). Al and aortic PP were obtained from pulse wave analysis of radial applanation tonometry, using transfer function (SphygmoCor Windows software). Results Baseline Al increased (P < 0.05) with aging, a lower height and a larger diastolic BP (DBP). Iso increased (P < 0.0001) HR, brachial SBP, brachial and aortic PP as compared with placebo. In contrast, Iso decreased (P < 0.05) Al, brachial DBP, peripheral PWV, but not aortic PWV. Decrease of Al induced by Iso was not related to PWV. In stepwise multiple regression changes in HR, brachial SBP and DBP were independent determinants of Al response to Iso (r = 0.78, P < 0.0001). Conclusions Our findings show that Al and PP fail as surrogate measures of arterial stiffness during beta-adrenergic stimulation. (C) 2004 Lippincott Williams Wilkins.