RESUMO
Aging is associated with increased central aortic systolic pressure (CSP) and pulse pressure which are predictive of cardiovascular events. Mechanisms implicated for higher central pressures include a higher forward incident pressure wave (P1), higher augmented pressure (AP), and shorter reflected wave round trip travel time (Tr). African-Americans (AA) have more frequent and deleterious blood pressure elevation. Using applanation tonometry, we studied the association of age and CSP with P1 and AP in 900 AA subjects. Data showed that in subjects ≤50 years old, CSP was mediated by AP but not P1 or Tr, whereas in those >50, CSP was mediated by both AP and P1 and to a lesser extent by Tr. Predictive models were significant (R(2) = 0.97) for both age groups. In conclusion, wave reflection is the primary determinant of CSP in younger AA, while in older subjects, CSP is mediated by both the magnitude and timing of wave reflection as well as aortic impedance.
RESUMO
UNLABELLED: Carotid-radial pulse wave velocity (PWV) normally decreases following release of upper arm cuff occlusion (hyperemia). Lower arm (LA) elicits less brachial artery dilation than upper arm (UA) occlusion but more closely reflects endothelial function. Using applanation tonometry, we compared changes (Δ) in PWV induced by UA and LA hyperemia in 65 healthy participants. Pulse wave velocity was measured serially. Both techniques decreased PWV maximally at 1 minute with gradual return to baseline by 9 minutes. ΔPWV(1min) was greater for UA than LA occlusion (-11.5% vs -6.8%, P = .02). Multivariate analysis showed arm location independently related to ΔPWV (P = .036). In participants with variable cardiovascular risk, PWV decline lessened with increasing Framingham risk for both techniques. IN CONCLUSION: UA and LA occlusion decrease PWV maximally at 1 minute after release of arterial occlusion. PWV(1min) decline are more marked after UA than LA occlusion and progressively lessens with increasing Framingham risk.
