Autopsy prevalence of intracranial atherosclerosis in patients with fatal stroke

Background and Purpose - The objective of this study was to determine the prevalence of intracranial plaques and stenoses and their causal role in patients with fatal stroke. Intracranial atherosclerosis is considered to be a rare condition with a severe prognosis. However, disease prevalence may be underestimated due to lack of appropriate diagnostic procedures. Methods - We performed a systematic analysis of intra-and extracranial arteries, the aortic arch, and the heart in 339 consecutive autopsies of patients with stroke. Clinical history, risk factors, imaging data, and general autopsy reports were analyzed. Patients with brain hemorrhage (n = 80) were used as control subjects. Results - Intracranial plaques and stenoses occurred in 62.2% (95% CI, 56.3 to 68.1) and 43.2% (95% CI, 37.2 to 49.3) of patients with brain infarction, respectively, compared with 48.8% (P < 0.05) and 17.5% (P < 0.001) of patients with brain hemorrhage, respectively. In the 43% of patients with brain infarction with at least one intracranial plaque-inducing luminal stenosis graded > 30%, the stenosis was considered to be causal in 5.8% of cases (n = 15) because of superimposed clot on ulcerated plaques; 27% of these patients had stenoses graded 30% to 75%. In multivariate analyses, diabetes and male sex were significantly associated with intracranial plaques and stenosis. History of myocardial infarction was significantly associated with intracranial plaques and previous stroke was associated with intracranial stenosis. Conclusions - Intracranial plaques and stenoses are highly prevalent in fatal stroke, and stenoses graded 30% to 75% may be causal. New arterial wall imaging techniques should be used to reevaluate the frequency and role of intracranial artery plaques in living patients with stroke.