New Study Says Clot Extraction Beats tPA in Stroke Treatment

A newly published independent study found that intra-arterial stroke treatment, including the use of a clot extraction technology, was significantly more effective than medical management with tissue plasminogen activator (tPA), the current standard of care.


Intra-arterial treatment, also called endovascular or interventional treatment, involves working inside the artery to remove the clot. One such system comes from Penumbra Inc., in the form of clot extraction devices. Penumbra provided an unrestricted grant for this trial, and its devices were among those included in the protocol.

Published in the New England Journal of Medicine, the so-called MR CLEAN (Multicenter Randomized Clinical trial of Endovascular treatment for Acute ischemic stroke in the Netherlands) prospective, randomized, controlled comparative effectiveness trial of stroke treatment has the potential to change the standard of care and improve functional independence for the 15 million stroke patients worldwide who currently have few treatment options.

The trial compared intra-arterial treatment with medical management using tissue plasminogen activator (tPA). The study enrolled 500 patients, and unlike previous studies, MR CLEAN specified that large vessel occlusion (LVO) had to be confirmed by CT angiography (CTA). Once confirmed, all patients were first administered tPA if eligible; 233 were then assigned to the intra-arterial treatment arm and 267 to the control arm. Intra- arterial devices were used at the discretion of the treating physician to include stent retrievers, direct aspiration or combination therapy. Primary endpoint was measurement of blinded modified Rankin Scale (mRS) scores at 90 days.

Results showed that intra-arterial treatment improved the rate of good functional outcome by 71 percent over treatment with medical management with tPA alone. Of patients who received intra-arterial treatment, 32.6% achieved a clinically defined positive stroke outcome compared with 19.1% of those who received medical management. Intra- arterial treatment was beneficial for all ages (18+), including the elderly (80+) – a population for whom intervention was previously thought to be risky. The trial began enrolling in 2010 and participating physicians used earlier generation intra-arterial technology. Currently available technology continues to improve upon the baseline set by MR CLEAN.

Investigator comments

“Despite being the number one cause of long-term adult disability, stroke has been one of the most undertreated and devastating diseases in the world,” said Albert J. Yoo, M.D., director of Acute Stroke Intervention in the Division of Interventional Neuroradiology/Endovascular Neurosurgery at Massachusetts General Hospital, assistant professor at Harvard Medical School and study author of MR CLEAN. “Now that intra-arterial treatment has been proven to provide significant benefits for stroke patients of all ages, we have a golden opportunity to dramatically improve the lives of stroke victims and, at the same time, help reduce costs in our healthcare system by returning patients to functional independence.”

“With the results of MR CLEAN, we have the needed evidence to support endovascular treatment in the fight against stroke, and the results are truly astounding,” said Michael J. Alexander, MD, FACS, Director of the Neurovascular Center, Professor of Neurosurgery at Cedars-Sinai and past president of the Society of NeuroInterventional Surgery. “They show that endovascular treatment can benefit a broad population of patients – not just younger patients as previously thought but older patients as well if treated early.”

Company comments

“The MR CLEAN study results provide evidence to support intra-arterial treatment in the fight against stroke and have the potential to change the standard of care,” said Adam Elsesser, chief executive officer, director and founder, Penumbra. “Penumbra is proud to have supported the MR CLEAN trial, and these important results will aid our efforts to improve access to intra-arterial treatment for the millions of stroke patients around the world.”

Source: Penumbra, Inc.

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