Aortic correlates of clinical markers of large artery structure and function. Effects of aging and hypertension

Background and aims: Non-invasive measures of large artery structure and function - such as aorto-femoral pulse wave velocity (PWV), arterial compliance (AC) and common carotid intima-media thickness (CCA IMT) - can predict new CV events, independently of traditional CV risk factors. However, neither their relations with aorta properties nor the effects of aging and hypertension on those relations are yet clear. Methods and Results: 40 subjects (18 M, 22 F; mean age 60±16 yrs, range 21-83 yrs) free of any acute CV event, valve disease or atrial fibrillation, were studied. Aortic IMT, diastolic diameter (D) and distensibility (Dist) were measured by transesophageal echocardiography at three different levels: ascending aorta (AA), distal aortic arch (Aarc) and descending aorta (DA). PWV was measured by Complior®. AC was measured as the ratio of stroke volume to pulse pressure. CCA IMT was measured by ultrasonography in diastole. The Dist, IMT, and D of each aortic segment were introduced alternatively into the regression models. After controlling for age, sex, traditional risk factors and prevalent CV disease, AC showed a significant positive association with the distensibility of proximal aortic segments, but no significant association with properties of distal aorta; PWV showed a significant positive association with proximal aorta wall thickness and a negative association with distal aorta distensibility; CCA IMT was positively associated with distal aorta wall thickness, but not with any explored property of the proximal aorta. None of these relationships differed between younger or older, normotensive or hypertensive subjects. Conclusions: Non-invasive measures of large artery structure and function are not equivalent with respect to their relations with aortic properties, so that AC seems to reflect proximal aorta function, PWV proximal aorta structure and distal aorta function, and CCA IMT distal aorta structure. Future studies are needed to confirm whether these relations identify a common pathogenetic mechanism, which may be the target for new therapeutic strategies.