Arterial enlargement in the atherosclerosis risk in communities (ARIC) cohort. In vivo quantification of carotid arterial enlargement. The ARIC Investigators.

BACKGROUND AND PURPOSE: The relation between arterial wall (intimal-medial) thickness and lumen narrowing is complex and has previously been studied predominantly at autopsy. B-mode ultrasound affords the opportunity to visualize both wall and lumen of the extracranial carotid arteries in vivo. Several studies have quantified the relation of various independent variables to wall thickness of carotid arteries in population-based samples, but the relation of age and wall thickness to interadventitial and lumen diameter has not previously been investigated in these samples.

METHODS: We used B-mode ultrasound to quantify the relation of arterial lumen diameter to age, arterial wall thickness, and arterial size (interadventitial diameter) of the extracranial carotid artery in 13,711 members of the Atherosclerosis Risk in Communities (ARIC) cohort.

RESULTS: Men had greater interadventitial diameters, thicker walls, and wider lumens than women. Wall thicknesses of the common carotid artery were greater by 21% in men and 22% in women aged 60 to 64 years compared with those aged 45 to 49 years (P

CONCLUSIONS: When arterial enlargement accompanies increased wall thickness, less lumen constriction results than expected. Quantification of these complex relations in vivo may provide new insight into the pathogenesis of symptoms related to vascular disease. Narrowing of the internal carotid artery lumen associated with thicker walls is consistent with the observation that stenosis develops in this region and often leads to symptoms.