Although the associations between chronic levels of arterial stiffness and blood pressure (BP) have been fairly well studied, it is not clear whether and how much arterial stiffness is influenced by acute perturbations in BP. The primary aim of this study was to determine magnitudes of BP dependence of various measures of arterial stiffness during acute BP perturbation maneuvers. Fifty apparently healthy subjects, including 25 young (20-40 yr) and 25 older adults (60-80 yr), were studied. A variety of BP perturbations, including head-up tilt, head-down tilt, mental stress, isometric handgrip exercise, and cold pressor test, were used to encompass BP changes induced by physical, mental, and/or mechanical stimuli. When each index of arterial stiffness was plotted with mean BP, all arterial stiffness indices, including cardio-ankle vascular index or CAVI (r = 0.50), carotid-femoral pulse wave velocity or cfPWV (r = 0.51), brachial-ankle pulse wave velocity or baPWV (r = 0.61), arterial compliance (r = -0.42), elastic modulus (r = 0.52), arterial distensibility (r = -0.32), β-stiffness index (r = 0.19), and Young's modulus (r = 0.35) were related to mean BP (all P < 0.01). Changes in CAVI, cfPWV, baPWV, and elastic modulus were significantly associated with changes in mean BP in the pooled conditions, while changes in arterial compliance, arterial distensibility, β-stiffness index, and Young's modulus were not. In conclusion, this study demonstrated that BP changes in response to various forms of pressor stimuli were associated with the corresponding changes in arterial stiffness indices and that the strengths of associations with BP varied widely depending on what arterial stiffness indices were examined.

These results suggest that the techniques used to assess arterial stiffness may not be interchangeable in clinical and research settings and that comparisons of findings obtained with different arterial stiffness measures should be conducted with caution.

Increased arterial stiffness is an independent marker of cardiovascular risk. However, some investigators have questioned the utility of arterial stiffness above and beyond the traditional blood pressure (BP) measurement as the change in arterial stiffness is often accompanied by corresponding changes in BP. Although the associations between chronic levels of arterial stiffness and BP have been fairly well studied, it is unclear if and how much arterial stiffness is influenced by acute BP changes.PURPOSETo determine the magnitude of BP‐dependence of arterial stiffness during acute BP perturbations.METHODSThirty apparently healthy subjects (46±4 years; 17 males) were studied. BP perturbations, including head‐up tilt, head‐down tilt, mental stress, isometric handgrip exercise, and cold pressor test were used to encompass blood pressure changes induced by physical, mental, and/or physiological stimuli. Arterial stiffness was measured with carotid‐femoral pulse wave velocity (PWV).RESULTSPWV was significantly associated with mean BP at rest (r=0.42). Mean BP was significantly changed during each perturbation, and changes ranged from △5±4 to △22±4 mmHg. Changes in mean BP and PWV were significantly correlated during mental stress (r=0.44), handgrip exercise (r=0.55), and cold pressor test (r=0.39). Significant associations were not found during head‐up tilt and head‐down tilt. CONCLUSIONThis study demonstrates that changes in arterial stiffness, as assessed by PWV, are significantly associated with acute BP changes during some BP perturbations but BP‐dependence of arterial stiffness is not observed in all perturbations.Supported by Fukuda Denshi.

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BackgroundHispanics are at least 1.5 times more likely to have mild cognitive impairment and exhibit dementia symptoms 7 years earlier than non‐Hispanic Caucasians. Regional cerebral hypoperfusion has been implicated as an initial event in the pathogenesis of dementia.AimTo compare cerebral perfusion in brain regions susceptible to vascular related hypoperfusion in Hispanic and non‐Hispanic Caucasian adults.MethodsApparently healthy middle‐aged Hispanic (n=16) and non‐Hispanic Caucasian (n=16) subjects were matched across age, gender, years of education, and cognitive status. Arterial spin labeled perfusion magnetic resonance imaging estimated cerebral blood flow in a priori brain regions of interest.ResultsMean cerebral perfusion was significantly lower in the Hispanic cohort than matched non‐Hispanic Caucasian peers in the right (38±32 vs. 76±22 ml/100 g/min, p=0.005) and left posterior white matter (39±32 vs. 72±31 ml/100 g/min, p=0.047). These differences remained significant even after controlling for blood pressure (p<0.05).ConclusionsMiddle‐aged Hispanic adults demonstrated significantly lower cerebral perfusion to the right and left posterior white matter compared with matched non‐Hispanic Caucasian peers. Hypoperfusion in these regions may contribute to cerebrovascular changes that could lead to early cognitive declines in the Hispanic population.Supported in part by grants from the American Heart Association (09BGIA2060722, APH), the National Institute of Neurological Disorders and Stroke (R01NS75565, APH), the National Institute on Aging (F31 AG040890, MMG), and American Federation for Aging Research (8A0024, APH).

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Blood pressure (BP) reactivity has been assessed by a variety of stimuli, including physical, psychological, and physiological perturbations, that can be further classified into cardiac or vascular in regard to the effector organs. In many BP reactivity studies, changes in brachial BP are taken as systemic changes and are combined with leg measurements to assess vasoactive states. Currently, it is unknown if leg BP behaves similarly to arm BP.PurposeWe compared BP changes between the brachial and post‐tibial arteries during acute BP perturbations.MethodsThirty apparently healthy subjects (57% males, 46±4 years) were studied. Both brachial and ankle systolic BP (SBP) were measured simultaneously with the oscillometric technique during resting baseline, head‐up tilt (HUT), head‐down tilt (HDT), mental stress (MS), isometric hand‐grip exercise (HG), and a cold pressor test (CPT).ResultsBrachial (bSBP) and ankle (aSBP) SBP at rest were significantly and highly correlated (r=0.81). Changes in bSBP were significantly and positively associated with changes in aSBP in response to HUT (r=0.46), HDT (r=0.53), MS (r=0.70), HG (r=0.63), and CPT (r=0.75). The magnitudes of bSBP and aSBP changes were not different n response to MS, HG, and CPT since all were within 5 mmHG. There were significant differences in the magnitude of changes in bSBP and aSBP in response to HDT (12±1 mmHg) and HUT (40±2 mmHg).ConclusionBoth brachial and ankle BP respond similarly in many vascular reactivity maneuvers. During head‐down and head‐up tilt, however, differences in their responses may be quite large, presumably due to the hydrostatic pressure gradients created during the maneuvers.Supported by Fukuda Denshi.