By Matthew E. Fink, MD

SOURCES: Saver J, et al, for the SWIFT PRIME Investigators. Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. N Engl J Med 2015; April 17 [Epub ahead of print] DOI:10.1056/NEJMoa1415061.

Jovin TD, et al for the REVASCAT Investigators. Thrombectomy within 8 hours after symptom onset in ischemic stroke. N Engl J Med2015; April 17 [Epub ahead of print] DOI: 10.1056/NEJMoa1503780.

Furlan AJ. Editorial. Endovascular therapy for stroke – It’s about time. N Engl J Med 2015; April 17 [Epub ahead of print] DOI: 10.1056/NEJMe1503217

On April 17, 2015, the New England Journal of Medicine published the results of two randomized clinical trials of endovascular stent-retriever clot extraction for ischemic stroke, simultaneous with their presentation at the European Stroke Conference. These two studies, added to those presented and published at the International Stroke Conference in February, bring the total number of studies to five that have shown dramatic benefits of this therapy in appropriately selected patients with acute ischemic stroke.

SWIFT PRIME enrolled 196 patients at 39 centers who were randomized into a thrombectomy group with the stent-retriever plus intravenous TPA compared to intravenous TPA alone within 6 hours of symptom onset. The primary outcome measure was the global disability score as measured by the modified Rankin scale score. The rate of functional independence, a modified Rankin scale score of 0 to 2, was higher in the intervention group than in the control group (60% vs 35%, P < 0.001). There were no significant differences between the groups in 90-day mortality or in the rate of symptomatic intracranial hemorrhage (0% vs 3%, P = 0.12). This study was terminated early because of the dramatic benefits seen in the early enrollment.

REVASCAT enrolled 206 patients at four centers in Spain, who were randomized to stent-retriever clot extraction vs medical therapy, which could include alteplase, within 8 hours of symptom onset. Once again, using the modified Rankin score as a measurement of global disability at 90 days, there was a dramatic difference in the groups, with the interventional group attaining independence, a modified Rankin score of 0 to 2, in 43.7% vs 28.2% in the medical group. Again, there was no significant difference in the rate of symptomatic intracranial hemorrhage or in mortality between the two groups.

Followup

In an accompanying editorial by a pioneer in this field, Dr. Anthony Furlan, the reason for success in these trials was identified as: 1) careful patient selection with documentation of large vessel occlusion, 2) improvement in technology, particularly with the stent retriever device, and 3) rapid speed to enroll and treat patients as quickly as possible.

Is it worth it?

Endovascular stent retriever therapy for acute ischemic stroke should be considered part of the standard therapy available to neurologists for patients who arrive at their hospitals with acute ischemic stroke, and stroke teams need to focus on speed and efficiency to successfully accomplish these tasks.