Rapid endovascular treatment appears to reduce mortality and improve functional outcomes among patients with acute ischemic stroke, according to data published online ahead of print in the New England Journal of Medicine. The study is known as Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE).
The research, along with the EXTEND-IA and MR CLEAN trials, provides additional evidence that endovascular treatment is effective for patients with ischemic stroke. These studies follow three stroke trials completed in 2013 that failed to show a benefit of endovascular therapy.
Patients Had a Small Infarct Core
Michael D. Hill, MD, Professor of Neurology at the University of Calgary in Canada, and colleagues designed an open-label trial with blinded outcome evaluation to analyze the effects of rapid endovascular treatment plus standard care. The researchers randomized patients with acute ischemic stroke to receive t-PA alone or t-PA plus endovascular treatment with available thrombectomy devices. Eligible participants had a small infarct core, an occluded proximal artery in the anterior circulation, and moderate to good collateral circulation. A small infarct core was defined as an Alberta Stroke Program Early CT score (ASPECTS) of 6 to 10. The investigators excluded patients with a proximal intracranial occlusion in the anterior circulation from the study if they presented at more than 12 hours after symptom onset. The trial’s primary outcome was the score on the modified Rankin Scale (mRS) at 90 days.
A total of 316 patients were randomized at 22 sites in Canada, the United States, the United Kingdom, Europe, and South Korea. After the publication of the MR CLEAN results, the data and safety monitoring board conducted an unplanned interim analysis of the data. The analysis indicated that the ESCAPE study had crossed a prespecified boundary for efficacy, and the board recommended that the study be halted.
Endovascular Treatment Reduced Disability
In all, 120 participants received t-PA and endovascular treatment, and 118 participants received t-PA alone. The average age of the population was approximately 70, and about 52% of participants were female. Median NIH Stroke Scale (NIHSS) score was 16 for the intervention group and 17 for the control group.
The median 90-day mRS score was 2 among patients who received endovascular treatment and 4 among patients who received t-PA alone. The proportion of patients with an mRS score of 0 to 2 at 90 days was 53.0% in the intervention group and 29.3% in the control group.
The mortality rate at 90 days among patients who received endovascular treatment was 10.4%, compared with 19.0% for patients who received t-PA alone. In addition, the rate of symptomatic intracerebral hemorrhage was 3.6% in the intervention group and 2.7% in the control group.
The researchers found no evidence of heterogeneity of treatment effect according to the presence or absence of cervical carotid occlusion or across any of the prespecified subgroups, which were defined by age, sex, baseline NIHSS score, baseline ASPECTS, occlusion location, and t-PA treatment status. All outcome variables showed a direction of effect in favor of the intervention.
Investigators used retrievable stents in 130 of the 151 participants (86.1%) who underwent an endovascular procedure, and 100 of these participants (77.0%) received a Solitaire stent manufactured by Covidien. In the intervention group, the median time from symptom onset to first reperfusion was 241 minutes, the median time from study CT to first reperfusion was 84 minutes, and the median time from groin puncture to first reperfusion was 30 minutes. Successful reperfusion occurred in 113 of 156 participants (72.4%) in the intervention group, including 79 of 112 participants who received IV t-PA and 34 of 44 participants who did not.
Eighteen patients in the intervention group had device-related or procedural complications. Serious adverse events in this group included hematoma at access site (three patients) and perforation of the middle cerebral artery (one patient). Fourteen patients in this group had adverse events that were not serious.
Endovascular Therapy Provides Benefits
“The trial confirms the benefit of endovascular treatment reported recently in the MR CLEAN trial,” said Dr. Hill. The study results could encourage a significant change in the treatment of acute ischemic stroke around the world, he added.
Post hoc analysis of previous studies of endovascular treatment indicated that achieving faster reperfusion was associated with a better clinical outcome, compared with slower reperfusion. “The ESCAPE trial achieved shorter interval times than those seen in past trials,” said Dr. Hill. “Critical to the achievement of rapid treatment was parallel decision making and action.