Timing of recanalization after intravenous thrombolysis and functional outcomes after acute ischemic stroke.
Yeo LLL., Paliwal P., Teoh HL., Seet RC., Chan BPL., Liang S., Venketasubramanian N., Rathakrishnan R., Ahmad A., Ng KWP., Loh PK., Ong JJY., Wakerley BR., Chong VF., Bathla G., Sharma VK.
BACKGROUND: Recanalization of occluded intracranial arteries remains the aim of intravenous (IV) tissue plasminogen activator (tPA) therapy in acute ischemic stroke (AIS). OBJECTIVE: To examine the timing and impact of recanalization on functional outcomes in AIS. DESIGN: A longitudinal cohort of consecutive IV tPA–treated patients with AIS from January 2007 through December 2010. Data were collected for demography, risk factors, stroke subtypes, blood pressure, and National Institutes of Health Stroke Scale scores. Early recanalization (ER) was identified by transcranial Doppler monitoring during the first 2 hours of treatment. Recanalization was reevaluated at 24 hours by computed tomographic angiography (CTA). Patients with ER and patent index artery at 24 hours on CTA were labeled as having persistent recanalization (PR). Recanalization at 24 hours on CTA regardless of transcranial Doppler status was labeled as CTR. Favorable outcome was defined as a modified Rankin Scale score of 0 to 1 at 3 months. SETTING: University hospital stroke center. PATIENTS: A total of 240 patients with AIS who underwent IV tPA treatment. RESULTS: Of 2238 patients with AIS, 240 (11%) received IV tPA. The median age was 65 years (range, 19-92 years) and 44% of the study group was male. The median National Institutes of Health Stroke Scale score was 17 (range, 3-35) and the median onset-to-treatment time was 149 minutes (range, 46-270 minutes). Of the 240 patients, 122 (50.8%) achieved favorable outcomes at 3 months. Data for ER, PR, and CTR were analyzed for 160 patients. Early recanalization was seen in 82 patients (51.3%); 67 cases (81.7%) had PR and 84 cases (52.5%) had CTR. National Institutes of Health Stroke Scale score at onset (odds ratio per 1-point increase, 0.938; 95% CI, 0.888-0.991), ER (odds ratio, 3.048; 95% CI, 1.537-6.046), PR (odds ratio, 5.449; 95% CI, 2.382-12.464), and CTR (odds ratio, 4.329; 95% CI, 2.131-8.794) were independent predictors of favorable outcomes. CONCLUSIONS: Intravenous tPA–induced arterial recanalization within the first 24 hours in AIS is a strong predictor of favorable outcomes at 3 months.