Variation in the Carotid Bifurcation Geometry of Young Versus Older Adults

Abstract

Background and Purpose-Retrospective analysis of clinical data has demonstrated major variations in carotid bifurcation geometry, in support of the notion that an individual's vascular anatomy or local hemodynamics may influence the development of atherosclerosis. On the other hand, anecdotal evidence suggests that vessel geometry is more homogenous in youth, which would tend to undermine this geometric risk hypothesis. The purpose of our study was to test whether the latter is indeed the case. Methods-Cross-sectional images of the carotid bifurcations of 25 young adults (24Ϯ4 years) and a control group of 25 older subjects (63Ϯ10 years) were acquired via MRI. Robust and objective techniques were developed to automatically characterize the 3D geometry of the bifurcation and the relative dimensions of the internal, external, and common carotid arteries (ICA, ECA, and CCA, respectively).

Morphometric and hemodynamic analysis of atherosclerotic progression in human carotid artery bifurcations

“…The ECA diameter in patients with carotid artery disease was significantly reduced (P Ͻ 0.05), while the CCA diameter was not statistically different from the control (P ϭ 0.18). Moreover, Patients [25][26][27][28][29][30] in Table 4, who were the youngest (ages 40 Ϯ 6 yr) and had extension of stenosis to the entire cervical ICA, showed smaller diameters of CCA and ECA than Patients [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] (ages 54 Ϯ 12 yr) with no stenoses in the distal regions of ICA. Patients 19 -24 in Table 4, who were the oldest (ages 71 Ϯ 7 yr) and had extension of stenosis to the middle of cervical ICA, showed larger angle 2 than Patients 1-18 and Patients [25][26][27][28][29][30] despite the lack of significant difference of angle 1.…”

“…3, A-C, show the variation of D fit along normalized ICA center lines with the stenosis near bifurcation (Patients [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] ) and in the middle of the vessel (Patients 19 -24 ) and with extension to the entire vessel (Patients [25][26][27][28][29][30] ), respectively. The black line, "control," represents the mean value of D fit (averaged over all controls) and error bars refer to SD.…”

“…Atherosclerotic plaques usually reside in artery bifurcations with complex flow patterns (6,7,10,13,15,17). Because of its clinical relevance to stroke (9), the morphometry of human carotid artery bifurcation [comprised of the left and right common (CCA), internal (ICA), and external (ECA) carotid arteries] (16) has received intensive investigation (3,23,24,27). Researchers have proposed various geometric risk factors for the incidence of atherosclerotic plaques, e.g., increased bifurcation angle and enhanced differences in area ratios including the flare, proximal curvature, and tortuosity of ICA.…”

A haemodynamic predictor of intraluminal thrombus formation in abdominal aortic aneurysms

“…In order to minimize the impact of boundary effects in the haemodynamic simulations, we consistently included extended segments of the common and internal carotid arteries; the external carotid artery was segmented up to its first branch. VMTK was also used to measure select geometric features such as the radius of the common carotid artery, defined as the average of multiple measurements taken along the vessel centreline, and the bifurcation angle between the internal and external carotids [8]. Subsequently, the processed level-set images were imported into a customized version of the open source code SimVascular [9], where two-dimensional segmentations were extracted at several cross sections via thresholding.…”

Widening of the basilar bifurcation angle: association with presence of intracranial aneurysm, age, and female sex

“…22 It is also generally accepted that geometrical aberrations are predisposWidening of the basilar bifurcation angle: association with presence of intracranial aneurysm, age, and female sex ing factors for vascular diseases, including atherosclerosis and IAs. 6,11,14,15,24 Wider bifurcation angles have been associated with aneurysm presence 11 and a particular hemodynamic environment at the bifurcation apex characterized by a wider stagnation area 7 of low pressure and WSS, which may allow aneurysms in these locations to grow larger than those located at bifurcations with narrow angles. 10 Basilar artery (BA) aneurysms account for 5%-8% of all IAs.…”