Flow dynamics with disruption of the laminar flow, vessel geometry and their relationship to the ICA atherosclerosis have always been interesting subject of research and discussion. Furthermore, the association of the vessel geometry and ICA atherosclerosis has been well established, but those studies did not take into consideration atherosclerotic risk factors, which independently can change vessel geometry. Interestingly, traditional risk factors influenced more CCA IMT than ICA IMT as one would expect. This gave more weight to the bifurcation geometry and change in hemodynamics as risk factor for ICA IMT.
Bijari et al. investigated prospectively obtained imaging and risk factor data. Selected patients were divided into 3 groups: The first group included 467 patients with no arterial stenosis. The second group consisted of 346 patients from the first group who were selected based on ICA and CCA wall thickness, previously established thresholds for inward remodeling, and from this group, 294 patients were identified with no lumen irregularities, thus third group was the least likely to have luminal geometry changed due to wall thickening.
In this study, vessels were evaluated using 3D MRI. Mean and maximal wall thickness was reported for CCA and ICA. Flare (maximum bifurcation cross section divided by CCA3 cross section) and curvature (term in description similar to length CCA3-distal ICA divided by straight line between these two points) were adopted for this study.
Result of this study demonstrated that geometric factors such as flare and curvature represent independent factors ICA wall thickness as previously suspected, in addition to previously identified effect on flow dynamics.
Despite some flaws in the design of this study as identified by the authors, it is wonderful to see confirmation of previously suspected relationships in the “segment specific” influence of hemodynamics on carotid wall thickness.