COMPENSATORY INCREASE IN COMMON CAROTID-ARTERY DIAMETER - RELATION TOBLOOD-PRESSURE AND ARTERY INTIMA-MEDIA THICKNESS IN OLDER ADULTS

Background and Purpose Common carotid artery (CCA) diameter is thought to increase as a consequence of hypertension and may increase as the thickness of the arterial wall increases. The purpose of this study wa s to determine CCA dimensions and correlate them with clinical feature s. Methods We performed a cross-sectional community-based study of adu lts 65 years of age and older, measuring inner and outer diameter of t he CCA in vivo with carotid sonography. Findings were correlated again st risk factors for atherosclerosis, CCA intima-media thickness (IMT), and echocardiographically determined left ventricular (LV) mass. Resu lts Independent variables showing strong positive associations with ou ter and inner CCA diameter included age, male sex, height. weight, and systolic blood pressure. As an independent variable, LV mass (r = .40 and r = .37, respectively; P < .00001) had a strong positive relation to inner and outer CCA diameters. The relationship between diameter a nd IMT was different. In a model that controlled for age, sex, and est imated LV mass, an increase of 1 mm in CCA IMT corresponded to a 1.9-m m increase in the outer diameter of the artery (P < .00001) but was no t significantly related to the inner diameter (slope = +0.07 mm; P = . 26. Conclusions Increase in the outer diameter of the CCA is associate d with subject size, sex, age, echocardiographically estimated LV mass , and CCA IMT. Increases in internal diameter of the CCA have similar relationships but are not related to IMT. This supports the hypothesis that the human CCA dilates as the thickness of the artery wall increa ses.