INVESTIGATION OF GEOMETRY AND ATHEROSCLEROSIS IN THE HUMAN CAROTID BIFURCATIONS

The common carotid artery bifurcation has attracted a special interest because atherosclerotic wall alterations are often found in this artery and, because of its unique shape, which influences the flow field and, hence, the location of wall alterations. However, current knowledge of its geometry is insufficient by a determination and quantification of the "geometric risk factors". At post mortem the 86 arteries from sixty-four autopsy subjects were excised and filled with a special resin at the proper transmural pressure. Eighty-six vessel casts of the carotid artery were fabricated and some etiologic factors such as age, sex and disease were collected. Furthermore, the arteries were processed according to the methods established by the World Health Organization in 1958 and the locations and level of the atherosclerotic lesions (fatty streaks, fibrous and severe plaques) were assessed. The following selected geometric parameters of these arteries were measured: the diameters of the main branches of the carotid bifurcation (common, external and internal carotid arteries), the angles between these main branches, the enlargement of the carotid sinus and the enlargement of the carotid bifurcation. Furthermore, 26 vessel casts were digitized and three-dimensional computer models were generated. These models were than used to assess other geometrical features such as curvature of the branches and non-planarity of the bifurcation. The analysis of the relationship between measured geometric parameters, etiologic factors and atherosclerotic lesions was performed. The geometric parameters vary considerably, presumably contributing to a corresponding variability in the distribution and level of the atherosclerotic lesions and local hemodynamic.