Ambulatory arterial stiffness index is not correlated with the pressor response to laboratory stressors in normotensive humans

Abstract

Ambulatory arterial stiffness index (AASI) is a novel estimate of arterial stiffness which independently predicts cardiovascular mortality, even in normotensive subjects. Additionally, other markers derived from ambulatory blood pressure (BP) monitoring, including variability (BPV), pulse pressure (PP), nocturnal dipping, and morning BP surge have all been shown to be predictive of endorgan damage and cardiovascular disease. Exaggerated cardiovascular reactivity to sympathoexcitatory stimuli may also predict future incidence of hypertension. The purpose of this investigation was to test the hypothesis that AASI and other derivations of ambulatory BP, including PP, 24-hr BPV, dipping, and morning surge, would be correlated with the pressor response to common physiological stress maneuvers. We measured continuous HR and arterial BP during headup tilt, mental stress, cold pressor test, and isometric handgrip to fatigue in 67 healthy, normotensive, non-obese individuals (43 women, 24 men, mean age ± SD: 28 ± 6 yr). Then 24-hr ambulatory BP was obtained, and AASI was defined as 1 minus the slope of diastolic on systolic BP in individual 24-h ambulatory BP recordings. Although all measures were widely variable among subjects, there was no relationship between AASI, PP, BPV, dipping, and morning surge with the pressor responses. We conclude that in the absence of aging, cardiovascular, or autonomic disease, the novel stiffness index (AASI) or other ambulatory BP indices are either poorly correlated with, or mechanistically unrelated to the complex pressor response to common provocations of sympathoexcitation.

Ambulatory arterial stiffness index correlates with ambulatory pulse pressure but not dipping status in patients with grade 1/grade 2 essential hypertension

“…37 Similarly, AASI has been found to negatively correlate with the morning surge in diastolic BP, daytime diastolic BP, 24-h mean arterial pressure variability, and nocturnal dips in systolic BP, diastolic BP and mean arterial pressure. 31 These data are broadly consistent with the observations in the present study. Interestingly, however, the values of AASI measured in the present study were not significantly different between the dipper and nondipper groups, perhaps suggesting that although BP variability is related to AASI, dipping status is not a major determinant in patients with grade 1/grade 2 hypertension.…”

The influence of baroreflex sensitivity on ambulatory arterial stiffness index in individuals with cardiovascular risk

“…On the other hand, BRS measured based on the time domain analysis in our study was mainly modulated by cardiac parasympathetic activity [31]. Coincidently, this observation is in accordance with the finding from a recent study that AASI was not associated with BP reactivity to laboratory stressors in young and normotensive individuals [32].…”

Association of Changes in Ambulatory Arterial Stiffness Index and Pulse Wave Velocity During Antihypertensive Treatment: The J-CORE Study

“…Previous studies have shown AASI be affected by the extent of the nocturnal BP fall, 3-7 BP variability expressed as the standard deviation, [12][13][14][15] and baroreflex sensitivity, 16 and therefore antihypertensive treatment which could modify these factors might in turn affect AASI in a manner independent of changes in arterial stiffness. Furthermore, previous findings, [17][18][19] taken together with the present findings, have suggested that AASI represents an integrated measure of ventriculo-arterial coupling, depending on both arterial (arterial stiffness and systemic vascular resistance) and cardiac factors (stroke volume and heart rate).…”