For patients with large-vessel ischemic stroke, endovascular thrombectomy produces better functional outcomes at 90 days than does optimal medical therapy, as long as the procedure is started within 7.3 hours of symptom onset, according to a report published online Sept. 27 in JAMA.
The benefit of thrombectomy was greatest when the procedure was begun under 2 hours from symptom onset, and it became nonsignificant after 7 hours and 18 minutes elapsed. This emphasizes “the importance of programs to enhance patient awareness, out-of-hospital care, and in-hospital management to shorten symptom onset-to-treatment times,” wrote Jeffrey L. Saver, MD, of the University of California, Los Angeles, and his associates.
Five major randomized trials have demonstrated the benefit of second-generation endovascular recanalization therapies over medical therapy in this patient population, but uncertainties persist regarding the timing of the intervention. For example, practice guidelines in the United States recommend thrombectomy until 6 hours after symptom onset, but the Food and Drug Administration allows thrombectomy devices to be used up to 8 hours after symptom onset and Canadian guidelines recommend the procedure for selected patients up to 12 hours after symptom onset.
The investigators for the five trials formed the Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials (HERMES) collaboration to pool their individual patient data and perform a meta-analysis to clarify the issue of timing. They assessed patients’ functional independence at 90 days using the modified Rankin Score (mRS). The study participants included 634 patients who had been randomly assigned to endovascular thrombectomy and 653 randomly assigned to medical therapy.
The intervention correlated with a substantially lower degree of patient disability at 90 days than did medical therapy: the mean mRS was 2.9 in the thrombectomy group and 3.6 in the medical therapy group. In addition, increasing delays in treatment were associated with higher levels of residual disability in the thrombectomy group but not in the medical therapy group, the investigators reported.
“Based on the current study, and assuming the findings are generalizable to the population of patients with acute ischemic stroke due to large-vessel occlusion, among every 1,000 patients achieving substantial endovascular reperfusion, for every 15-minute faster ED door-to-reperfusion time, an estimated 39 patients would have a less-disabled outcome at 3 months, including 25 more who would achieve functional independence (mRS 0-2),” Dr. Saver and his associates wrote (JAMA. 2016;316:1279-88).
These findings reinforce current recommendations to attempt endovascular thrombectomy when the procedure can be initiated within 6 hours of symptom onset, and they also “provide evidence that potentially supports strengthening of the recommendation for treatment from 6 through 7.3 hours after symptom onset,” they added.
No specific sponsor of this study was cited. Dr. Saver reported ties to Medtronic, Stryker, Cognition Medical, Covidien, Neuravi, BrainsGate, Pfizer, Bristol-Myers Squibb, Boehringer Ingelheim, ZZ Biotech, St. Jude Medical, and Genentech. His associates reported ties to numerous industry sources.