LOW BLOOD PRESSURE AMPLIFICATION IS ASSOCIATED WITH EXAGGERATED BLOOD PRESSURE RESPONSE TO STANDING IN YOUNG TO MIDDLE AGE HYPERTENSIVE ADULTS

Objective: Evidence has been accumulating that exaggerated blood pressure (BP) response to standing (RTS) is associated with adverse outcomes. There is general agreement that the mechanisms of high RTS differ according to age with a vascular stiffness type in older individuals and a cardiac reactive type in younger adults. However, whether the stiffness gradient between central and peripheral arteries and/or reflecting properties of microcirculation are, at least in part responsible for an exaggerated RTS in the young age has never been explored. The aim of this study was to assess the relationship of high RTS with BP amplification in a sample of young to middle age stage 1 hypertensive adults. Design and method: We studied 304 subjects (229 men) from the HARVEST study (mean age 37.4±10.3 years). To assess RTS, BP was measured 1,2, and 3 minutes after standing-up. Central BP and augmentation index (AIx) estimated from radial artery were evaluated with the Specaway DAT system and hemodynamic variables with HDI Pulse Wave device. In multivariate regression analyses, RTS was used as dependent variable and systolic BP amplification as predictor adjusting for several confounders and risk factors. Results: Age-adjusted systolic BP amplification was 22.4±0.9 mmHg in men and 11.9±1.8 mmHg in women (p<0.001). Independent predictors of low systolic BP amplification were female sex (p=0.010), smoking (p=0.002), AIx (p=0.012), and peripheral resistance (p=0.003). Systolic BP amplification either expressed as absolute values (p<0.001), or normalized for central BP (p=0.001) was independently and negatively associated with RTS. In multinomial logistic regression analysis, low systolic BP amplification was independently associated with higher odds for the top RTS tertile (OR: 1.03; 95% CI: 1.01–1.06, p=0.005, using the bottom RTS tertile as the reference). Similar results were obtained when data were adjusted also for pulse wave velocity and when pulse pressure amplification was used as predictor. Conclusions: These data show that peripheral arterial dysfunction may explain an exaggerated RTS not only in elderly subjects but also in younger individuals. This may account for the increased risk of cardiovascular events associated with orthostatic hypertension in young to middle age adults.