Intracranial atherosclerosis: structure, clinical aspects and risk factors

Introduction. Atherosclerosis is a complex pathophysiological process with a wide range of clinical manifestations. Active research is underway to determine the prevalence of intracranial atherosclerosis across different ethnic groups, the role of modifiable and non-modifiable risk factors in its pathogenesis, and the advances in diagnostic algorithms for patients with extra-/intracranial atherosclerosis. The aim was to evaluate manifestations of intracranial atherosclerosis (patterns of intracranial artery lesions, including pathomorphological findings) and identify potential associations between known risk factors and intracranial atherosclerosis in patients with cerebrovascular disease. Materials and methods. During the first phase, a retrospective analysis of autopsy protocols was conducted for 166 patients (66% men) hospitalized at the Research Center of Neurology between 1976 and 2007. The second phase involved clinical, laboratory, and imaging data from 120 patients (59% men) with atherosclerotic disease of the brachiocephalic arteries. These patients were divided into two subgroups: a main subgroup with intracranial artery involvement combined with extracranial atherosclerosis (n = 60) and a control subgroup with isolated extracranial artery involvement (n = 60). Results. Pathomorphological assessment revealed a high rate of atherosclerotic lesions in the carotid artery system at both extra- and intracranial levels. One-third of patients had ≥50% atherosclerotic stenosis in intracranial arteries without significant extracranial stenosis. Multivariate logistic regression analysis identified obesity (odds ratio [OR] 3.22), male sex (OR 6.17), and low-density lipoprotein levels (OR 2.5) as the most significant independent clinical laboratory factors associated with intracranial atherosclerosis. Conclusion. The role of intracranial atherosclerosis in cerebrovascular events is underestimated. Overlapping neurological and generalized manifestations of isolated intra- and extracranial atherosclerosis may give a misleading impression of the true prevalence of intracranial atherosclerosis.