Clinical and Radiological Outcomes after Intracranial Atherosclerotic Stroke: A Comprehensive Approach Comparing Stroke Subtypes

Abstract

Background: We previously reported that intracranial large-artery atherosclerotic stroke (ICAS) had a relatively large salvageable area of less severe hypoperfusion. However, information regarding the outcome after ICAS is lacking. We hypothesized ICAS would show more favorable clinical and radiological outcomes than other stroke mechanisms. Methods: Consecutive patients underwent admission (n = 149) and follow-up (n = 80) multiparametric magnetic resonance imaging (MRI) for acute middle cerebral artery infarcts within 6 h of symptom onset. T_max perfusion lesion maps were generated. We assessed the difference in the degree of infarct growth ([follow-up diffusion-weighted imaging (DWI) volume – initial DWI volume]/initial penumbra volume) and the presence of excellent long-term outcome [defined as a modified Rankin scale (mRS) score ≤2 and a modified Barthel index (mBI) ≧90 at 3 months]. Results: Of 149 patients, 24 (16.1%) had ICAS, 75 (50.3%) had cardioembolic stroke, 21 (14.1%) had extracranial large-artery atherosclerotic stroke, and 29 (19.5%) had cryptogenic embolic stroke. Despite a higher recurrence rate in patients with ICAS compared to other subtypes (p = 0.026), the long-term outcome was better in ICAS (p = 0.003 for an mRS score ≤2 and p = 0.004 for an mBI ≧90). Among 80 patients who underwent follow-up MRI, patients who had minimal infarct growth (less than 10%) were more prevalent among the patients with ICAS (p = 0.004). Multivariate testing revealed that ICAS was independently associated with both excellent long-term outcome (OR = 3.45; 95% CI = 1.11–10.78) and minimal infarct growth (OR = 10.40; 95% CI = 1.20–90.11). Conclusion: Our data show that patients with ICAS have favorable clinical and radiological outcomes compared with other subtypes.