Correlation between the Occlusion Site and Clinical Outcome after Acute Ischemic Stroke

Objective The significance of early mild clinical improvement after intravenous tissue plasminogen activator (IVtPA) treatment is unclear. Therefore, we examined whether the timing of clinical improvement after IVtPA predicted the clinical outcome at 3 months. Methods Consecutive patients with acute cerebral infarction in the anterior circulation who received IVtPA treatment within 3 hours of the onset of symptoms were enrolled in the study. Patients were classified according to the timing of clinical improvement [early responder (ER), National Institutes of Health Stroke Scale (NIHSS) score improved >= 4 points or who had a score of 0 within 2 hours after IVtPA; late responder (LR), a similar improvement between 2 and 24 hours; and non-responder (NR)] and according to the arterial occlusion site (P group, internal carotid artery and proximal middle cerebral artery M1 region; and D group, distal M1 and M2). Results Ninety-three patients [median age, 74 (67-79) years; 54 men (58%); median NIHSS score, 11 (7-16)] were enrolled in the study. The P group consisted of 48 (52%) patients and the D group consisted of 45 (48%) patients. Thirty-eight patients (41%) were classified as ERs, 20 (22%) as LRs, and 35 (38%) as NRs. On a multivariate regression analysis, the P group [odds ratio (OR), 3.24; 95% confidence interval (CI), 1.08-10.45; p=0.036] and NR (OR, 4.04; 95% CI, 1.29-14.27; p=0.016) were independent predictors of a poor outcome. ER (47%, p=0.01) and LR (45%, p=0.01) patients showed fewer poor outcomes than NR (77%) patients, but the rate did not differ significantly between the ER and LR patients. Conclusion Early mild clinical recovery did not predict a good outcome. The occlusion site was a stronger predictor of clinical improvement after IVtPA administration.