Using perfusion imaging to identify patients with salvageable brain tissue following ischemic stroke is the key to extending the window for thrombolysis out to 9 hours.
The results of the EXTEND trial show that more patients presenting between 4.5 and 9 hours treated with tPA (alteplase) under these conditions achieved a score of 0 or 1 on the modified Rankin scale (indicating no deficits or minimal deficits, respectively) than those give placebo.
The EXTEND trial is published in the May 9 issue of The New England Journal of Medicine. The results were first presented at the International Stroke Conference (ISC) in Hawaii earlier this year.
These results open up the possibility of treating many more stroke patients with thrombolysis.
The study is positive and provides level 1 evidence for tPA out to 9 hours (including wake-up strokes) in patients with suitable imaging showing that brain tissue is salvageable.
There have been two previous studies looking at late tPA with a similar design — ECASS-4 and EPITHET, and a meta-analysis of all three trials is about to be presented at this months European Stroke Organisation Conference (ESOC) meeting in Milan, Italy.
225 patients with ischemic stroke who had hypoperfused but salvageable regions of brain detected on automated perfusion imaging were randomly assigned to receive intravenous alteplase or placebo between 4.5 and 9 hours after the onset of stroke or on awakening with stroke (if within 9 hours from the midpoint of sleep).
The primary outcome (a score of 0 or 1 on the modified Rankin scale at 90 days) occurred in 40 patients (35.4%) in the alteplase group and in 33 patients (29.5%) in the placebo group.
Symptomatic intracerebral hemorrhage occurred in 7 patients (6.2%) in the alteplase group and in 1 patient (0.9%) in the placebo group.