February 12th, 2015

Three Trials Show Benefits of Thrombectomy in Stroke Patients

Three new studies offer important additional evidence that early treatment with current thrombectomy devices that extract clots from blood vessels in the brain can lead to improved outcomes in carefully selected stroke patients. The trials were stopped early based on efficacy following positive findings last year from another trial, MR CLEAN. The three new trials were presented today at the AHA/ASA International Stroke Conference in Nashville; two of the trials were published simultaneously in the New England Journal of Medicine.

In the ESCAPE trial, 316 patients were randomized within 12 hours of the onset of symptoms to standard care or standard care plus the use of a thrombectomy device. Patients enrolled in the trial were carefully selected. They all had a proximal vessel occlusion, a small infarct core, and moderate-to-good collateral circulation.

At 90 days 53% of patients in the intervention group versus 29.3% in the standard care group were considered functionally independent (modified Rankin score of 0-2)  (p<0.001). There was also a significant reduction in mortality, from 19% in the control group to 10.4% in the treatment group (p=0.04). Symptomatic intracerebral hemorrhage occurred in 3.6% of the treatment group and 2.7% of the standard care group (p=0.75).

“The trial confirms the benefit of endovascular treatment reported recently in the MR CLEAN trial,” the investigators wrote.

The smaller EXTEND-IA trial was stopped after only 70 patients were enrolled. These patients had a blockage of the internal carotid or middle cerebral artery with evidence of reversible ischemic range and a small infarct. They were randomized to thrombolysis alone or thrombolysis plus thrombectomy. All patients were treated within 4.5 hours of the onset of symptoms.

Reperfusion at 24 hours and early neurologic improvement — the coprimary outcomes — were both significantly better in the treatment group. The percentage of ischemic territory that had undergone reperfusion was 100% in the treatment group versus only 37% in the control group (p<0.001). At three days early neurologic improvement was seen in 80% of the treatment group versus 37% of controls (p=0.002). At 90 days 71% of patients in the treatment group had achieved functional independence, compared with 40% in the control group (p=0.01).

The investigators noted that “a unique feature” of their study “was the use of standardized, universal CT perfusion-imaging selection to exclude patients with large ischemic cores and without evidence of clinically significant salvageable ischemic brain.”

The SWIFT PRIME trial studied 196 patients receiving thrombolysis for confirmed large vessel anterior circulation occlusions within six hours of the onset of symptoms. Following randomization half received additional endovascular therapy with the Solitaire device. Functional independence, defined as a score under two on the modified Rankin scale, was achieved in 60.2% in the treatment group and 35.5% in the control group (p=0.0008). There was no significant difference in mortality at 90 days (9.2% versus 12.4%, p=0.50).

The authors calculated that “for every two and half patients treated, one more patient has a better disability outcome” and that “for every four patients treated, one more patient is independent at long time follow-up.”

Medtronic/Covidien was the sole sponsor of EXTEND-IA and SWIFT PRIME, and a partial sponsor of ESCAPE.



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