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DAWN: Endovascular therapy beneficial beyond 6 hours after acute ischemic stroke
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Results of the DAWN trial, presented at the European Stroke Organization Conference, show that endovascular therapy to remove a stroke-causing blood clot in the brain was superior to medical therapy alone even when the procedure was performed between 6 and 24 hours after stroke.
Although current guidelines from the American Heart Association/American Stroke Association and the European Stroke Association endorse endovascular therapy for stroke in a time window of 0 to 6 hours, there are a number of centers around the world who will perform an endovascular procedure beyond 6 hours after stroke onset, according to the study background.
“The ... guidelines all endorse endovascular therapy for stroke as backed by level 1 evidence in the 0-to 6-hour time window, so most of the systems of care are designed to capture these patients,” Tudor Jovin, MD, professor of neurology and neurosurgery at the University of Pittsburgh Medical Center, told Cardiology Today’s Intervention. “Most patients who present beyond 6 hours do not get the same type of imaging studies to identify them as harboring a large-vessel occlusion as the ones who come in earlier in time. The hope is that based on the results of this trial, the practice will change and that patients within 24 hours will be screened for interventions just like the ones within 6 hours are.”
According to Jovin, the researchers set out to determine whether endovascular treatment with a clot retrieval device (Trevo, Stryker Neurovascular) for acute ischemic stroke with large-vessel occlusion is beneficial in terms of clinical outcomes compared to standard medical treatment alone in patients presenting in the 6- to 24-hour time window. Patients had certain clinical and imaging characteristics indicating they may benefit from endovascular therapy, including a small area of irreversible brain damage but a larger brain tissue area threatened by blood loss.
The researchers randomly assigned 206 patients to either receive endovascular therapy or standard medical therapy after arriving at the hospital more than 6 hours after stroke onset.
Researchers planned to enroll up to 500 patients, but the trial was stopped early after it was determined endovascular therapy provided significant clinical benefit.
The primary endpoint of functional independence at 90 days occurred in 48.6% of the endovascular group vs. 13.1% of the medical-therapy group, according to the researchers. The number needed to treat to prevent one severe disability was 2.8.
Jovin and colleagues found that patients in the DAWN cohort had poor outcomes without reperfusion.
“If reperfusion is not [achieved] in the blocked vessel, the percentage of patients who return to the independent level of functioning was 13% compared to almost 50% of patients who are treated with ... Trevo. The rate of good outcomes, meaning the independent level of activity in these patients, is 35.5% higher than with medical therapy alone,” Jovin said in an interview. “This translates into a number needed to treat of 2.8 or 3, which is one of the highest treatment effects we've seen in any kind of acute stroke therapy.” – by Dave Quaile
Reference:
Jovin T, et al. Official welcome and large clinical trials. Presented at: European Stroke Organization Conference; May 16-18, 2017; Prague.
Disclosure: The study was funded by Stryker. Jovin reports no relevant financial disclosures.