Patients treated with intravenous alteplase 4.5 to nine hours after experiencing an acute ischemic stroke, or on awakening with stroke symptoms, have a higher rate of excellent functional outcomes three days later compared with patients treated with placebo, according to a recent study. Yet, current protocol restricts alteplase to within 4.5 hours after a stroke. Ischemic stroke patients who presented between six and nine hours after stroke onset, but who had low Rankin scores (indicating minimal neurologic deficits), had better functional outcomes after alteplase compared with those receiving a placebo.

Recanalization at 24 hours after stroke occurred in more than two-thirds of patients in the alteplase group versus about 40% of the placebo group, and early major neurologic improvement at 24 hours occurred in nearly 25% of the alteplase group compared with about 10% of the placebo group. Deaths within 90 days were similar for both groups.

These new findings come from Extending the Time for Thrombolysis in Emergency Neurological Deficits (EXTEND), a randomized, multicenter, placebo-controlled trial of 225 patients. The results showed that treating ischemic stroke patients 4.5 to nine hours after stroke onset helps to preserve functional capabilities if patients have salvageable brain tissue. The study also confirmed that pharmaceutical thrombolysis is as effective as mechanical revascularization. Yet, as of 2013, few patients hospitalized for ischemic stroke in the United States received intravenous thrombolysis.

Overall, EXTEND shatters an important barrier to acute stroke treatment, according to a commentary on the study. Extending the time window makes more patients eligible to receive treatment for acute stroke. More importantly, stroke centers with the imaging capability to detect a mismatch between the size of the ischemic core and the penumbra could treat patients with stroke many hours after the onset of symptoms, including those who awake with a stroke.-Carol Potera

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