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The Cutting Edge

Reopening Blocked Brain Arteries

An experimental device for removing blood clots in stroke patients dramatically outperformed the standard mechanical treatment, a UCLA study has found.

In use in acute stroke with large vessel occlusion (top), the SOLITAIRE device was found to achieve rapid flow restoration through the clot (middle), and attain a high rate of recanalization (bottom).

The SOLITAIRE Flow Restoration Device is among a new generation of tools designed to remove blood clots from blocked brain arteries in patients experiencing a stroke. It has a self-expanding, stent-like design and, once inserted into a clot using a thin catheter tube, it compresses and traps the clot. The clot is then removed by withdrawing the device, thus reopening the blocked blood vessel.

In the first U.S. clinical trial of SOLITAIRE, the device opened blocked vessels without causing symptomatic bleeding in or around the brain in 61 percent of patients. The standard Food and Drug Administration-approved mechanical device - a corkscrew-type clot remover called the MERCI Retriever - was effective in 24 percent of cases.

Use of the SOLITAIRE also led to increased survival rates three months after a stroke. There was a 17.2 percent mortality rate with the new device, compared with a 38.2 percent rate with the older one. "This new device heralds a new era in acute stroke care," says Jeffrey L. Saver, M.D., director of the UCLA Stroke Center.

"We are going from our first generation of clot-removing procedures, which were only moderately good in reopening target arteries, to now having a highly effective tool. This really is a game-changing result."

At the suggestion of a safety-monitoring committee, the trial was ended nearly a year earlier than planned due to significantly better outcomes with the experimental device.


A mesh-columned cage, SOLITAIRE is designed to expand and capture a clot at multiple grabbing points, pulling it out more cleanly.

About 87 percent of all strokes are caused by blood clots blocking a blood vessel supplying the brain. The stroke treatment that has received the most study is the FDA-approved clot-busting drug known as tissue plasminogen activator, but this drug must be given within four-and-a-half hours after the onset of stroke symptoms, and even more quickly in older patients.

When clot-busting drugs cannot be used or are ineffective, the clot can sometimes be mechanically removed during, or beyond, the four-and-a-half-hour window. The current study, however, did not compare mechanical clot removal to drug treatment.

"Nearly a decade ago, our UCLA Stroke Center team invented the first stroke retrieval device - the MERCI Retriever - and now we are pleased to have helped develop and successfully test a superior, next-generation clot-removing device," says UCLA radiologist Reza Jahan, M.D., the study's principal neurointerventional investigator. "It is exciting to have a highly effective new tool that can improve the outcomes for more stroke patients."


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