Trials highlighted at ISC show success of endovascular therapy

SubArticle1_largeAfter two decades of essentially no positive results in acute stroke therapy trials, thrombectomy showed substantial therapeutic effects in a trio of endovascular therapy trials presented during ISC 2015. The three trials presented follow similarly positive results from MR CLEAN, published in late 2014.

“The most exciting science at this meeting was clearly the endovascular trials,” said Kyra Becker, MD, ISC 2015 Program Committee chair. “We saw the primary results from SWIFT PRIME, EXTEND-IA and ESCAPE. The trials were all overwhelmingly positive and the results very consistent. The chance of a good outcome nearly doubled in subjects who underwent endovascular therapy.”

Both ESCAPE and EXTEND-IA were presented at ISC and simultaneously published in the New England Journal of Medicine. Most patients in both trials received intravenous tPA. The addition of endovascular therapy significantly improved outcomes at 90 days compared to medical treatment alone.

Preliminary data from SWIFT PRIME showed significant improvement in functional outcomes at 90 days, the primary endpoint.

There were no significant safety concerns in any of these trials, said Dr. Becker, professor of neurology and neurological surgery, and co-director of the UW Medicine Stroke Center at the University of Washington, Seattle.

“It is very clear that time is of the utmost importance,” she said. “Based on the data presented to date, it appears that therapy should be delivered within six hours of symptom onset, and the sooner reperfusion is achieved, the better the chances for a good outcome. The question now is how we get these patients with an occlusion of large intracranial vessels to a comprehensive stroke care center that can provide endovascular therapy in a timely fashion.”

MR CLEAN researchers presented a post-hoc analysis of the effect of anesthesia on endovascular outcomes. The data suggest that patients who received endovascular treatment under general anesthesia fared more poorly than patients who received treatment under conscious sedation. The association between general anesthesia and worse outcomes is not conclusive, Dr. Becker said, but the results support the findings in other studies. The clinical implication is that endovascular therapy should be performed under conscious sedation whenever possible.

If there is a downside to these promising data, it is the epidemiology of stroke. Dr. Becker cautioned that the percentage of stroke patients who actually qualify for endovascular therapy is smaller than headlines might suggest.

About 85 percent of strokes are ischemic, she said. But only about 10 percent of stroke patients now receive tPA, a factor in the success of all four trials. Only a small percentage of patients treated with tPA will be eligible for endovascular therapy based on their vascular pathology and other factors.

“These trials represent a huge win, but the intervention is not applicable to the majority of patients with stroke,” she said. “What we know for now is that endovascular therapy works in patients with severe stroke due to occlusion of a large intracranial vessel when they are treated in an expedient fashion, and that is a very good thing.”

As exciting as the endovascular results were, ISC 2015 covered more than clot removal. The CADISS study compared anticoagulant therapy to antiplatelet therapy for the prevention of stroke in patients following carotid and vertebral artery dissection.

“Until now, we hadn’t any evidence from prospective randomized controlled trials regarding the appropriate antithrombotic treatment in patients with dissection, but providers were staunchly adherent to their beliefs,” Dr. Becker said. “This study showed that the risk of stroke/recurrent stroke in this population is exceedingly low and that the risk does not seem to vary by which antithrombotic is used. These data are very reassuring and suggest that it’s hard to go wrong with either treatment.”

Another study, ICARE, was a Phase III randomized controlled trial of evaluating intensive, individualized therapy for upper arm deficits compared to usual care. While the study showed no differences in the primary outcomes among the treatment groups, the trial was a success and should spur efforts to develop and test more effective stroke recovery and rehabilitation strategies, she said.