Recently, I heard about the future of acute stroke treatment: retrieving the culprit blood clot with a removable stent, also known as stent retrievers, stentrievers, and stent-on-a-stick.
Dr. Aitziber Aleu, an interventional neurologist from Hospital Germans Trias i Pujol near Barcelona, presented the combined experience from three Barcelona-area hospitals using two different brands of stentrievers to treat 89 acute stroke patients during March 2008-December 2010. This was the largest series of stroke patients yet reported who underwent this type of treatment, and a rapt, electrified audience of stroke interventionalists who heard her speak at the International Stroke Conference in Los Angeles kept her on the podium after her talk was over, peppering her with questions.
Photo credit: Mitchel L. Zoler
Stent-on-a-stick is one of many stent retrievers.
Her most notable finding: Using an average of 1.4 passes per patient to remove the clot from a cerebral artery, the stentrievers produced good blood flow, TIMI 2 or 3, in 91% of patients, with hemorrhage occurring in 11% of patients.
At 90 days after treatment, 47% had a good outcome, with a modified Rankin scale score of 2 or less, and mortality was 20%. All those numbers were either as good, or better than what is routinely achieved with the main clot-removal devices currently used, the MERCI clot-spearing device and the Penumbra clot-suction machine. The recanalization rate is better, the procedure time is shorter, the hemorrhage rate about the same.
“The advantage is the stents are very easy to use and they are faster, recanalizing in fewer passes,” Dr. Aleu told me. She said that the self-expanding stent quickly and effectively entangles the clot within its struts so that the clot leaves when the stent is removed.
“Stent retrievers are the next generation of tools,” said the session’s co-chair, Dr. Adnan H. Siddiqui, director of stroke and neurosurgical research at the University of Buffalo. Clot retrieval with an average of 1.4 passes “is incredible,” he said. The approved devices usually require four or five passes. He said that has used one of the two devices now in testing, the Solitaire, on about a dozen patients as part of the 200-patient, U.S.-based SWIFT trial, which is comparing this stent retriever against the MERCI. (The other retrievable stent used in Barcelona is the Trevo). The stent retriever is “more maneuverable and more deliverable” than what’s out there, he told me. And he was thrilled that 47% of patients had good recoveries, with modified Rankin scores of 2 or less.
“The best results now are 40%-45% of patients” reaching this level of stroke recovery. “Fifty percent is the next target,” he said, a goal he hopes will be reached in the SWIFT trial and in other stent retriever studies now underway.
–Mitchel L. Zoler (on Twitter@mitchelzoler)