Intravenous Thrombolysis in Expanded Time Window (3-4.5 hours) in General Practice with Concurrent Availability of Endovascular Treatment

Abstract

Introduction: A randomized double-blind trial (ECASS III) demonstrated that intravenous (IV) recombinant tissue plasminogen activator (rt-PA) administered between 3 and 4.5 hrs after the onset of symptoms significantly improved clinical outcomes in patients with acute ischemic stroke. In May 2009, the American Stroke Association guidelines recommended the use of IV rt-PA for patients presenting within 3 and 4.5 hrs after symptom onset.

Objective: To determine the rate of patients treated with IV rt-PA within the 3- and 4.5-hr time window and associated comparative outcomes in general practice.

Methods: We retrospectively reviewed all patients who were treated with IV rt-PA at two comprehensive stroke centers from September 1, 2008 to July 31, 2010 and identified a total of 98 patients. In addition, we identified patients who arrived to the ED of those centers within 2.5 to 4 hrs of symptom onset between January 1, 2007 and June 30, 2010 and received only endovascular treatment. We compared the rates of favorable outcome (determined by using modified Rankin scale 0-2 at discharge and 3-month follow-up), and National Institutes of Health Stroke Scale (NIHSS) score improvement by ≥ 4 points or 0 at discharge among patients treated with IV rt-PA within 3-4.5 hrs with those who received IV rt-PA within 0-3 hrs, and subsequently with patients presenting at similar time window treated only with endovascular treatment.

Result: Out of the total 98 IV rt-PA treated patients, 84 of them were treated within 0-3 hrs, and 14 within the 3--4.5 hrs. Twelve patients received endovascular treatment only for the specified time window. Mean admission NIHSS score ± standard deviation (SD) was 11.90 ± 6.72, 8.57 ± 5.40, and 11.75 ± 8.06, for the 0--3, 3--4.5 hrs, and endovascular only treatment groups, respectively. Favorable clinical outcome at discharge (50% vs. 56%, p=0.77), 3 months (64% vs. 64%, p=1.0), and NIHSS score improvement (43% vs. 58%, p=0.38) were not different between those treated within 3-4.5 and 0-3 hrs time windows. There appeared to be a non-significantly higher rate of favorable outcomes at discharge (25% vs. 50%, p=0.24), and at 3 months (42% vs. 64%, p=0.43) among patients treated with IV rt-PA within 3-4.5 hrs compared with those treated with primary endovascular treatment.

Conclusion: An additional 14% of patients received IV rt-PA because of treatment window expansion from 3 to 4.5 hrs. Outcomes were comparable to those treated within 3 hrs of symptom onset. The shift of those patients from primary endovascular treatment does not appear to adversely affect patient outcomes.