Factors and outcomes associated with recanalization timing after thrombolysis

Background: A substantial number of acute stroke patients do not respond immediately to aggressive intra-arterial (IA) recanalization therapy. The factors and outcomes associated with timing of recanalization after IA thrombolysis, however, have not yet been determined. Methods: Factors and outcomes in 75 acute ischemic stroke patients treated with IA urokinase (± intravenous tissue plasminogen activator) within 6 h of onset were retrospectively assessed. Immediate recanalization (IR) was assessed by the angiogram at the end of the IA procedure, and delayed (DR) and no (NR) recanalization were assessed by 5-day MR angiography. Modified Rankin Scale (mRS) scores were determined at 7 days and 3 months. Results: Of the 75 patients, 32 (42.7%) achieved IR, 21 (28%) achieved DR, and 22 (29.3%) showed NR. Good functional outcomes (mRS score ≤2) at 7 days and 3 months were observed in 59.4 and 62.5%, respectively, of the IR group, 14.3 and 38.1% of the DR group, and 22.7 and 27.3% of the NR group (p = 0.001 for 7 days, p = 0.028 for 3 months). Multivariate analysis showed that cardioembolism [odds ratio (OR), 3.74; 95% confidence interval (CI), 1.15-12.19] and middle cerebral artery occlusion (OR, 3.23; 95% CI, 1.04-10.04) were independent predictors of IR or DR compared with NR. Age (OR, 0.86; 95% CI, 0.77-0.95) and initial NIHSS score (OR, 1.20; 95% CI, 1.04-1.37) were independent predictors of DR compared with IR. Conclusions: Patients receiving IA thrombolysis show different clinical and radiological characteristics according to the timing of recanalization. Earlier identification of DR patients and their more efficient recanalization may improve overall clinical outcomes after IA thrombolysis.