Prevalence study of proximal vertebral artery stenosis using high-resolution contrast-enhanced magnetic resonance angiography

Purpose: To evaluate the prevalence of proximal vertebral artery stenosis, compared with those of the distal vertebral/ basilar artery and extracranial internal carotid artery, in a large population of stroke and non- stroke patients. Material and Methods: Nine- hundred- and- thirty- five patients who underwent high-resolution contrast- enhanced magnetic resonance angiography in a regional general hospital were categorized into six groups based on neurological symptoms and disease: an asymptomatic group ( n = 182), a minor symptom group with headache or dizziness ( n = 519), a cardiac group with coronary artery steno- occlusive disease ( n = 15), a hemorrhagic group with old cerebral hemorrhage ( n = 26), an anterior circulation infarct group ( n = 121), and posterior circulation infarct group ( n = 72). Prevalence of stenosis of the proximal vertebral artery, distal vertebral/ basilar artery, and internal carotid artery was analyzed. Results: The prevalence of stenosis of the proximal vertebral artery, distal vertebral/ basilar artery, and internal carotid artery was 12.9%, 5.5%, and 7.2%, respectively, in the study population, and rose as the age increased ( P < 0.0001 for all arteries). The prevalence of stenosis of the proximal vertebral artery, distal vertebral/ basilar artery, and internal carotid artery was 3.3%, 0.5%, and 1.1%, respectively, in the asymptomatic group; 8.3%, 2.1%, and 3.7%, respectively, in the minor symptom group; 13.3%, 6.7%, and 6.7%, respectively, in the cardiac group; 19.2%, 7.7%, and 7.7%, respectively, in the hemorrhagic group; 27.3%, 8.3%, and 25.6%, respectively, in the anterior circulation infarct group; and 44.4%, 36.1%, and 16.7%, respectively, in the posterior circulation infarct group. This increasing tendency of stenosis accordingly was statistically significant ( P < 0.0001 for all arteries). Conclusion: The prevalence of proximal vertebral artery stenosis was highest, compared with those of the distal vertebral/ basilar artery and internal carotid artery, although the clinical significance of proximal vertebral artery stenosis should be investigated in further studies.