Background and purpose: Extracranial atherosclerosis, proximal to the carotid bifurcation and V3 segment of the vertebral artery, is considered to be an infrequent condition with a benign prognosis. However, its prevalence may be underestimated due to lack of data. We aimed to determine the prevalence of proximal extracranial plaques and stenosis in the common carotid artery, innominate and subclavian arteries, and proximal vertebral artery.
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; 259 patients had brain infarction; 80 patients had brain hemorrhage and were used as control subjects. Clinical history, risk factors, imaging data, and general autopsy reports were analyzed.
Results: Proximal extracranial plaques and stenosis were present in the arteries of 46.9% and 19.8% of patients, respectively, without a significant difference between brain infarction and brain hemorrhage groups. Proximal extracranial atherosclerosis occurred more frequently in the proximal vertebral artery than in other arteries (stenosis prevalence 12.7% versus 5.3% in the common carotid artery) and in patients with posterior circulation brain infarction (except for the posterior cerebral artery territory). More specifically, atherosclerosis in the proximal vertebral artery was significantly associated with posterior circulation brain infarction (age- and sex-adjusted OR, 2.31; 95% CI, 1.28 to 4.17 for plaques and 2.10; 95% CI, 1.01 to 4.38 for stenosis) using patients with isolated anterior circulation infarctions as control subjects.
Conclusions: Proximal extracranial atherosclerosis was frequent and was significantly associated with brainstem infarcts. These findings support the importance of a systematic workup, including the evaluation of proximal extracranial atherosclerotic lesions.