Program News

Due to promising results in a multi-center trial, the UCLA Stroke Center has expanded its research to continue studying a non-drug therapy to treat – and even reverse – strokes by using a mechanical clot retrieval device. The MERCI (Mechanical Embolus Removal in Cerebral Ischemia) trial using the Concentric Retrieval device has been evaluated in patients with acute strokes at UCLA Medical Center since May 2001. The primary purpose is to study the safety and effectiveness of the Concentric Retriever when used in stroke patients primarily within eight hours of the onset of stroke symptoms.

Significance

Patients enrolled in the MERCI investigational trial are suffering the most severe type of stroke. These strokes are so devastating, that without effective treatment, these patients are highly likely to end up in a nursing home or dying.

Stroke most commonly occurs when there is a blockage of blood flow to one of the arteries to the brain. The blockage is often caused by a clot and can result in brain damage or death. By restoring blood flow to the brain, stroke symptoms may get better or may be prevented from getting worse.

Stroke is the third leading cause of death, the number one cause of disability in adults and the second most common reason for people being confined to a nursing home. Stroke awareness for both the patient and patient’s family is the first and most important step to effective treatment.

“Time is brain.” Treatment can be more effective if given quickly, and only within the first few hours from stroke
onset.

Application

The Concentric Retriever device is a thin tube containing a metal alloy wire with “shape memory.” The wire tip is formed to “remember” a corkscrew shape, then straightened and threaded into a tiny catheter. The catheter containing the wire is inserted into a patient’s artery in the groin and threaded up to the brain. Once the catheter tip reaches the clot, the wire is pushed out of the catheter to protrude into the clot. The wire’s shape memory causes it to return to its corkscrew shape and the coiled wire latches on to the clot the way a corkscrew lodges in a wine bottle’s cork. A tiny balloon momentarily inflates to stop blood flow through the artery to prevent the clot from breaking off and the clot is drawn out using the embedded coil.

Twenty-four patients have been enrolled in the MERCI investigational trial at UCLA and 22 have been treated with the Concentric Retriever. The patients ranged in age from 28 to 90 years old, with an average age of 64. Fifty-nine percent of the patients treated were men. The Concentric Retriever was able to retrieve the clot in 50 percent of the cases and restored flow to the brain tissue in 48 percent of the cases. (over)

In patients where flow was restored to the brain tissue, half of the patients showed significant improvement instantly. One month after the procedure, five patients had died, most due to the severity of their stroke.

To date, the only drug approved by the Federal Drug Administration to treat stroke is tissue plasminogen activator (TPA) administered within the first three hours of stroke symptom onset. However, TPA has its limits and can cause bleeding into the brain in some patients. Standard stroke therapy with TPA results in complete or near complete recovery in only one out of eight patients treated. The Concentric Retriever provides another option in opening blocked blood vessels and potentially reversing a stroke. The MERCI Retriever avoids the risk of bleeding associated with TPA and is an alternate to TPA in the many patients who are ineligible for TPA.

The Concentric Retriever was invented at UCLA and sponsored by Concentric Medical of Mountain View, CA. Although the MERCI investigational study is still in the early stages and is showing promise in treating strokes, the UCLA Stroke team emphasizes that advances in stroke research can only be effective if patients seek immediate help at the onset of a stroke.

The UCLA Stroke Center is recognized globally as a leader in the treatment of stroke and is committed to research and advancements in stroke therapy. The UCLA Stroke Center team includes experts in the fields of emergency medicine, stroke neurology and interventional neuroradiology.

Contact

UCLA Stroke Hotline 310 825-6466, 24 hours a day for emergency response for patients in the LA county
vicinity. Emergency transport may be available.

Sidney Starkman, M.D,
Professor of Emergency Medicine and Neurology
UCLA Stroke Center

Jeffrey Saver, M.D.
Professor of Neurology
UCLA Stroke Center

Chelsea Kidwell, M.D.
Associate Professor of Neurology
UCLA Stroke Center

David Liebeskind, M.D.
Assistant Professor of Neurology and Radiology
UCLA Stroke Center

Gary Duckwiler, M.D.
Professor of Interventional Neuroradiology

Reza Jahan, M.D.
Assistant Professor of Interventional Neuroradiology

Fernando Viñuela, M.D.
Professor of Interventional Neuroradiology