Carotid Bifurcation Geometry as Assessed by Ultrasound is Associated with Early Carotid Atherosclerosis

Abstract

Atherosclerosis usually develops at geometrically susceptible areas, despite the impact of systemic risk factors on the entire vascular system. The aim of our study was to investigate whether carotid bifurcation geometry as assessed by ultrasound is associated with early carotid atherosclerosis, regardless of the presence of known atherosclerotic risk factors. A nonrandomized prospective study was undertaken, including subjectsof both genders, aged 50-60years, without known cardiovascular family history,and symptoms and/or signs of cardiovascular disease. Clinical assessment andultrasoundof the carotid bifurcation evaluating geometrical characteristics, ultrasonic biopsyscore(UBS), intima-media thickness (IMT), and the presence of plaque were recorded. Two hundred one subjects (95 men/106 women; mean age: 55years) provided 286 carotid bifurcations associated with atherosclerotic risk factors and 114 without (one poor imaging). While UBS in the right common carotid artery (CCA) was higher in subjects with atherosclerotic risk factors but free of plaque (P=0.035), larger diameter of the bulb (dBULB) (P<0.001), lower ratios of internal carotid artery diameter+external carotid artery diameter/diameter of CCA ([dICA+dECA]/dCCA) (P=0.004), and (dICA2 + dECA2)/dCCA2 (P=0.025) were independently associated with higher CCA IMT. The presence of plaque among the total 400 carotid bifurcations was associated in the left and right CCA with lower values of bulb diameter/dCCA (dBULB/dCCA) (P=0.014) and (dICA+dECA)/dCCA (P=0.001), respectively. Among subjects without atherosclerotic risk factors (n=114), the presence of plaque in the right CCA was associated with lower values of (dBULB+dECA)/dCCA (P=0.001) and that in the left with lower values of dBULB/dCCA (P=0.001). Different dimensional ratios of the carotid bifurcation assessed by ultrasound are associated with the development of early carotid atherosclerosis independently from the presence of atherosclerotic risk factors. Carotid atherosclerotic process may be side dependent.