Hemodynamic Correlates of Abnormal Aortic Root Dimension in an Adult Population: The Strong Heart Study

Abstract

BackgroundWe evaluated the relationship of aortic root dimension (ARD) with flow output and both peripheral and central blood pressure, using multivariable equations predicting ideal sex‐specific ARD at a given age and body height.Methods and ResultsWe measured echocardiographic diastolic ARD at the sinuses of Valsalva in 3160 adults (aged 42±16 years, 61% women) from the fourth examination of the Strong Heart Study who were free of prevalent coronary heart disease, and we compared measured data with the theoretical predicted value to calculate a z score. Central blood pressure was estimated by applanation tonometry of the radial artery in 2319 participants. ARD z scores were divided into tertiles representing small, normal, and large ARD. Participants with large ARD exhibited greater prevalence of central obesity and higher levels of inflammatory markers and lipids (0.05<P<0.0001). Stroke volume, heart rate, and both cuff and central diastolic blood pressure were progressively greater from small to large ARD (all P<0.0001). Pulse pressure was higher in small ARD (P<0.0001). In multivariable analysis, ARD z score was related positively to stroke volume, either cuff or central diastolic blood pressure, and negatively to pulse pressure. Large ARD was also independently correlated to higher waist circumference and percentages of neutrophils and plasminogen activator inhibitor‐1 (all P<0.01).ConclusionsAortic root dilatation is associated with high diastolic blood pressure, high stroke volume, central fat distribution, and inflammatory status. In contrast, at a given diastolic blood pressure and stroke volume, aortic root dilatation is associated with lower pulse pressure and systolic blood pressure.

Aortic root dimension and arterial stiffness in arterial hypertension

“…Consistent with our results, small ARD, as raw, unindexed measure at the level of Valsalva sinuses, has been associated with prevalent hypertension and suggested to be an important etiological factor in development of systolic hypertension [8,11,12]. Also cross-sectional analyses from the Framingham Heart Study reported that ARD was positively associated with both mean and DBP, whereas it was negatively associated with PP and SBP [9], both indirect markers of increased arterial stiffness.…”

“…Consequently, different methods of measuring ARD potentially impose a major bias in the evaluation, because the arterial remodeling in aging and hypertension tends to increase leading edge-to-leading edge diameter, while reducing the trailing edge-to-trailing edge diameter, making results from metaanalyses that mixes studies using both these measure of ARD confusing and difficult to interpret [29]. Most recently, we demonstrated in the cohort of the Strong Heart Study, that age, sex and body size-independent aortic dilatation evaluated as in the present analysis, strongly depends on the extend of hemodynamic determinant, including BP components and LV performance [12].…”

“…The z-score of ARD (ARD-z) was generated based on the difference between the observed ARD and ARD p , divided by the sex-specific SD of the observed ARD value [12]. Thus, a positive ARD-z score indicate an ARD larger than expected and a negative value indicates an ARD smaller than expected.…”

“…Consequently, small ARD has been suggested to be associated with early arterial stiffening [9][10][11][12]. Further contributing to the inconsistency of findings on the relationship between ARD and arterial stiffness, no significant association between ARD and blood pressure (BP) could be detected in a recent meta-analysis of eight clinical trials [13].…”

“…Most studies are cross-sectional, largely blunting the possibility to explore pathophysiological changes of native ARD, as well as the impact of major determinants of the variance of ARD, such as age, sex, body size and left ventricular (LV) performance, as recently suggested [12]. Most recently, we have developed an algorithm to estimate ideal, sex-specific, individual values of ARD [14], for a given age, and body build that might be used to minimize the impact of major confounders.…”