VIDEO: Ischemic-stroke thrombectomy use widens and refines

Dr. Jeffrey Saver

“We now have about 100 certified comprehensive stroke centers in the U.S.,” and by definition comprehensive stroke centers have the capability of treating patients with endovascular thrombectomy, noted Dr. Jeffrey Saver, professor of neurology and director of the stroke unit at the University of California, Los Angeles.

“Certification of these centers did not begin until about 2-3 years ago. But we probably need 300-400 of these centers” to provide thrombectomy to most U.S. stroke patients, he said. “A lot of additional hospitals are close to certification. I anticipate that over the next 1-2 years we will be in the neighborhood of having the number of centers we need,” Dr. Saver said in an interview.

Making thrombectomy better

In addition to expanding availability, the specifics of how endovascular thrombectomy gets delivered is evolving. A major trend is movement toward a “parallel processing” model, in which patients with an acute clinical presentation of a stroke amenable for endovascular treatment simultaneously undergo CT angiography to confirm and localize the large-artery clot causing their stroke, receive intravenous TPA, and undergo preparation for the endovascular access needed to remove the clot.

A pooled analysis of the recent, positive endovascular thrombectomy trials that was presented at the conference showed how quick you need to be to obtain a benefit from the procedures. “This gives us a starting point to further improve the target metrics for imaging and puncture times,” Dr. Saver said. “We want to shorten door-to-needle times for TPA and door-to-puncture times for thrombectomy, and the processes that need to be addressed for rapid delivery of both of these are very similar. We need for patients to only make a pit stop in the ED; we need to have the catheterization team ready to go in the thrombectomy suite within 30 minutes; and we need to emphasize speed in access to the target clot rather than time-consuming diagnostic angiography.”

“We now face the issue of how to best integrate TPA treatment and clot removal.” Dr. Kent said. “People are still trying to work that out. With parallel processing there is some overuse of resources: Some patients recover with TPA alone and don’t need thrombectomy. We are getting closer to the cardiology model of MI treatment. It’s now clear that there needs to be a simple, safe, effective way to do both TPA treatment and thrombectomy. We need to model ourselves on the cardiology experience.”

“If you can deal with the TPA decision in the same room without moving patients from room to room, from a scanner to a catheterization suite, you can really shorten the time to treatment,” Dr. Smith explained. “This is identical to the model that cardiologists have developed. We should now consider taking stroke patients directly to the angiography room in addition to administering TPA. We still need cross-sectional imaging, but the quality of the image from an angiography suite is probably sufficient to make a TPA decision. So you can start TPA while you are getting arterial access. The idea is simultaneous approaches to the patient instead of serial.”

“The whole system moves at the same time to eliminate wasted time,” Dr. Alberts summed up.

One of the big questions that has come up in this effort to speed up treatment and carve the quickest route to endovascular thrombectomy is whether TPA remains necessary. The skeptics’ position is, why waste time administering TPA if you’re also going to take out the offending clot?

The answer, at least for now, is that all signs indicate that giving TPA helps and is worth delivering.

“The 2015 thrombectomy trials had big differences among them in the dosage of TPA administered, and in the percentage of patients who received TPA. When 100% of patients received TPA they had the best outcomes,” Dr. Kent said. “There was a clear synergistic relationship between thrombectomy and TPA. There has been a trend to think about sending patients straight to thrombectomy and skipping TPA, but my colleagues and I think that we need to hold off on doing that. For now, if a patient is eligible to receive TPA they should get it and then quickly move to endovascular therapy. We are not yet ready to know it’s okay to go straight to endovascular treatment. In SWIFT-PRIME, it was pretty clear that the good outcomes were attributable to both [thrombectomy plus TPA]. Treating patients with TPA helps soften the clot to make it easier to remove, and improves flow through collateral arteries.”

“Our data in Memphis show that patients do better with thrombectomy plus intravenous TPA than on TPA alone,” agreed Dr. Lucas Elijovich, a neurologist at the University of Tennessee Health Science Center in Memphis, in an interview.