Large-Artery Stenosis Predicts Subsequent Vascular Events in Patients with Transient Ischemic Attack

BACKGROUND AND PURPOSE: We investigated subsequent vascular events in patients with transient ischemic attack (TIA) and determined the predictors of such events among vascular risk factors including large-artery disease, TIA-symptom duration, and acute ischemic lesions on diffusion-weighted imaging (DWI). METHODS: We identified 98 consecutive patients with TIA who visited a tertiary university hospital and underwent DWI and brain magnetic resonance angiography within 48 hours of symptom onset. We reviewed the medical records to assess the clinical characteristics of TIA, demographics, and the subsequent vascular events including acute ischemic stroke, TIA, and myocardial infarction. RESULTS: Large-artery disease was detected in 55 patients (56%). Ten patients (10%) experienced TIA symptoms for longer than 1 hour, and acute infarctions on DWI were identified in 30 patients (31%). During the mean follow-up period of 19 months, seven patients (7%) had an acute ischemic stroke and 20 patients (20%) had TIA. Retinal artery occlusion in two patients, spinal cord infarction in one patient, and peripheral vascular claudication in one patient were also recorded. Cox proportional-hazards multivariate analysis revealed that large-artery disease was an independent predictor of subsequent cerebral ischemia (hazard ratio [HR], 2.8; 95% confidence interval [CI], 1.1-7.1; p=0.02) and subsequent vascular events (HR, 2.9; 95% CI, 1.2-6.7; p=0.01). CONCLUSIONS: In patients with TIA, large-artery disease is an independent predictor of subsequent vascular events. Acute infarction on DWI and a symptom duration of more than 1 hour are not significantly correlated with a higher risk of subsequent vascular events. These findings suggest that the underlying vascular status is more important than symptom duration or acute ischemic lesion on DWI.

Prevalence and Risk Factors of Intracranial Atherosclerosis in an Asymptomatic Korean Population

BACKGROUND AND PURPOSE: Intracranial atherosclerosis (ICAS) is one of the major risk factors for ischemic stroke, particularly in Asian populations. We investigated the prevalence and risk factors of ICAS in asymptomatic subjects. METHODS: We prospectively evaluated 835 asymptomatic Korean adults who voluntarily visited a tertiary referral hospital for a health screening examination that included brain magnetic resonance angiography. The subjects had no history of stroke or transient ischemic attacks; those who had potential cardiac sources of emboli were excluded. ICAS and extracranial atherosclerosis were defined as a reduction in luminal diameter of at least 50%. Vascular risk factors were screened through questionnaires, interviews, and examinations. RESULTS: ICAS was found in 25 subjects (3.0%) and extracranial atherosclerosis was found in 4 patients (0.5%). No patient had combined lesions. ICAS was distributed in 31 arteries in 25 subjects: anterior cerebral arteries (5 subjects, 16%), middle cerebral arteries (16 subjects, 52%), posterior cerebral arteries (8 subjects, 26%), and distal internal carotid arteries (2 subjects, 7%). The ratio of ICAS of the anterior circulation (23 of 31 arteries with ICAS, 74%) to that of the posterior circulation (8 of 31 arteries with ICAS, 26%) was 3:1. The ratio of ICAS (23 of 27 arteries with atherosclerosis in the anterior circulation, 85%) to extracranial atherosclerosis (4 of 27 arteries with therosclerosis in the anterior circulation, 15%) was 6:1. An older age [odds ratio (OR)=1.05, 95% confidence interval (CI)=1.00-1.10] and hypertension (OR=2.41, 95% CI=1.01-5.72) were independent risk factors for ICAS. CONCLUSIONS: ICAS is more prevalent than extracranial atherosclerosis among neurologically asymptomatic Korean adults. Subjects with ICAS are significantly older and have an increased frequency of hypertension compared to those subjects without atherosclerotic stenosis.