VIDEO: Ischemic-stroke thrombectomy use widens and refines

Simpler imaging also saves time

Although it’s not yet proven, another new wrinkle in working up acute ischemic-stroke patients for TPA and thrombectomy treatment is the idea that simpler and more widely available CT imaging, especially CT angiography of cerebral arteries, may suffice for confirming and localizing the culprit clot.

This concept received a significant boost at the International Stroke Conference in data reported from the Pragmatic Ischaemic Stroke Thrombectomy Evaluation (PISTE) trial, yet another study that compared treatment with TPA alone with TPA plus endovascular thrombectomy, this time in 65 randomized patients treated at any of 11 U.K. centers. PISTE had a low enrollment level because the trial stopped prematurely, in July 2015, following the news that several fully completed trials had collectively established the superiority of endovascular thrombectomy plus TPA, thereby making it unethical to continue yet another randomized study.

Dr. Keith W. Muir

This premature stoppage prevented PISTE from itself producing a statistically significant difference for its primary efficacy endpoint in favor of the combined treatment, although the results did show a nominal advantage to using thrombectomy plus TPA over TPA alone that was fully consistent with the other studies, Dr. Keith W. Muir reported at the conference.

But what made the PISTE results especially notable was that the trial achieved this consistent outcome with a “simpler” imaging protocol for patients during their workup that used only CT angiography, avoiding the cerebral CT perfusion imaging or MRI used in several of the other TPA-plus-thrombectomy versus TPA-only trials, noted Dr. Muir, professor of neuroscience and head of the stroke imaging group at the University of Glasgow.

“PISTE raises the question of how much imaging is necessary,” Dr. Kent commented.

“The PISTE results are exciting. A lot of us believe that all we need to know is that there is a blockage in a target vessel,” Dr. Smith said. “If we have that information, then we can identify a population of patients who will benefit from [thrombectomy]. CT angiography is simple and can easily fit into work flows.”

“PISTE used a very simple imaging system that makes thrombectomy even more applicable and generalizable to less resourced health systems,” Dr. Saver said. “Although the results from PISTE were not internally statistically significant because the trial ended early, the results were consistent with the external studies of thrombectomy, so it provides further evidence for benefit from thrombectomy.” And because the consistent results were achieved with simpler imaging it suggests simpler imaging may be all that’s needed.

“That’s a major question to wrestle with,” Dr. Saver suggested. “We need addition trials with a head-to-head comparison of simpler and more sophisticated imaging so we can tailor treatment to patients who would benefit from simpler and faster imaging.”

Dr. Kent had no disclosures. Dr. Kim has received research funding from SanBio and Biogen. Dr. Smith served on the data safety and monitoring board for a trial funded by Stryker. Dr. Alberts has been a consultant to Genentech. Dr. Saver has been a consultant to Stryker, Neuravi, Cognition Medical, Boehringer Ingelheim, and Medtronic. Dr. Elijovich has been a consultant to Stryker and Codman and received research support from Siemens. Dr. Muir has received research support from ReNeuron and unrestricted grants from Codman and Covidien.

mzoler@frontlinemedcom.com

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