A longtime hypothesis has now been confirmed with Level I, Class A evidence: Endovascular therapy can be highly beneficial in patients with acute ischemic stroke compared with IV t-PA alone.
That’s the resounding message out of this year’s International Stroke Conference, where results of five randomized clinical trials — MR CLEAN, EXTEND-IA, ESCAPE, SWIFT PRIME and REVASCAT — were presented. The studies consistently showed that, compared with IV t-PA alone, endovascular therapy within six to eight hours after stroke onset:
- Yielded superior recanalization rates
- Produced higher rates of functional independence at 90 days
- Was safe, with no significant increase in symptomatic brain hemorrhage or mortality
‘Turning a historic corner’ in acute strokeThe five studies are now published in the New England Journal of Medicine and represent the “turning of a historic corner” in acute stroke therapy, according to a statement from the National Institute of Neurological Disorders and Stroke.
The studies compared interventional therapy using new-generation mechanical thrombectomy devices (“stent retrievers” such as Medtronic’s Solitaire™ FR and Stryker’s Trevo®) vs. best medical management for acute ischemic stroke caused by large vessel occlusion, which represents a large subset of ischemic stroke cases.
Benefits from better stent-retriever devicesThe new studies put to rest lingering uncertainties about the efficacy of endovascular stroke therapy that arose from results of three trials released in 2013 that showed no advantage over IV t-PA alone. One of the key reasons for the shift in results since then appears to be related to the introduction of stent-retriever technology.
The new-generation catheter-based devices used in the latest studies deploy a metal mesh within the clot, in contrast to earlier devices that acquired control of the clot proximally or distally. The moment the mesh is deployed, a channel is opened to permit blood flow to starved brain tissue. The mesh expands to become one with the clot, allowing clot and mesh to be retrieved as a unit. The result is faster, more complete recanalization. But still not fast enough to stop the neuronal cascade of death.