Endovascular Therapy Benefited Patients vs. Alteplase Alone in EXTEND-IA

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NASHVILLE — Among certain patients with ischemic stroke, endovascular therapy with the Solitaire Flow Restoration (FR) stent retriever led to improved reperfusion, early neurologic recovery, and better functional outcome compared with those who received alteplase alone, according to late-breaking trial data.

The EXTEND-IA trial was presented at the International Stroke Conference 2015. In the trial, Bruce C.V. Campbell, MBBS, BMedSc, PhD, FRACP, of the Royal Melbourne Hospital in Australia, and colleagues enrolled patients who were receiving 0.9 mg of alteplase per kilogram of body weight less than 4.5 hours after the onset of ischemic stroke.

According to study methodology, patients had occlusion of the internal carotid or middle cerebral artery and computed tomographic (CT) perfusion imaging indicated salvageable brain tissue and ischemic core of less <70 mL. Patients were randomly assigned to receive either endovascular thrombectomy with the Solitaire FR stent retriever (n=35) or to continue with alteplase alone (n=35).

Reperfusion at 24 hours and early neurologic improvement — defined as at least an 8-point reduction on the National Institutes of Health Stroke Scale or a score of 0 or 1 at day three — were the coprimary endpoints. Ninety-day modified Rankin functional score was a secondary endpoint.

After randomization of 75 patients, the trial was stopped prematurely due to efficacy.

Campbell and colleagues reported a higher rate of ischemic territory that underwent reperfusion at 24 hours in the endovascular therapy group (median, 100% vs. 37%; P<.0001).

Rates of early neurologic improvement at three days were also higher with endovascular therapy (80% vs. 37%; P=.002), which was initiated at a median of 210 minutes after stroke onset. Additionally, the rates of functional outcome at 90 days were increased in the endovascular therapy arm, with more patients achieving functional independence, which was defined as modified Rankin scale score of 0 to 2 (71% vs. 40%; P=.01).

Rates of death (endovascular, 9% vs. alteplase, 20%; P=.18) and symptomatic intracerebral hemorrhage (endovascular, 0% vs. alteplase, 6%; P=.49) did not significantly differ between groups.

In an interview with Neurology Advisor, Albert Favate, MD, chief of vascular neurology and assistant professor of neurology at NYU Langone Medical Center in New York, said the EXTEND-IA trial confirms that thrombus extraction with the Solitaire device is beneficial over tPA alone.

“However, the concurrent use of tPA may also limit any thrombus formation in collateral supply,” he said. “The limiting factor in use of tPA is that once clot size approaches 8 mm, immediately tPA will only work 1% for clot dissolution. EXTEND-IA supports the need for use of thrombolytic and mechanical extraction with the Solitaire.”

Favate added that the number needed to treat (NNT) in the EXTEND-IA and MR. CLEAN trials to have a positive effect was 3 patients. “The NNT for IV tPA alone in the first hour of arrival with treatment is 6.5 patients, so, by comparison, combined treatment with tPA and intra-arterial clot extraction is far superior as demonstrated in the NNT [analysis]."

For more coverage of the International Stroke Conference 2015, go here.

References

  1. Campbell BCV et al. Late-Breaking Trial #2. Presented at: International Stroke Conference 2015; Feb. 11-13, 2015; Nashville, Tennessee.
  2. Campbell BCV et al. N Engl J Med. 2015; doi:10.1056/nejmoa1414792.
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