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Doctors Remove Clots with a Corkscrew


	Dr. Pierre Gobin, right, examines images from an angiogram that visualizes the arteries that supply the brain and helps doctors guide the Retriever to the clot.

	Dr. Dana Leifer examines images from an MRI.

Dr. Pierre Gobin and Dr. Dana Leifer are studying whether MRI (magnetic resonance imaging), in an emergency setting, can help determine if ischemic stroke patients would benefit from intervention with a device known as the MERCI Retriever. The MERCI Retriever is a tiny corkscrew-like device that can be threaded through the circulatory system and into an artery near the surface of the brain to ensnare and remove a clot.

(An ischemic stroke occurs when a blood vessel becomes blocked or narrowed, resulting in a decrease in the blood supply to the brain.)

In this trial, doctors will use MRI scans to determine if there is a blocked artery that the device can potentially open. They will also use the MRI to estimate the amount of tissue that has already been irreversibly damaged and the amount of tissue that is at risk but can be salvaged if blood flow is restored. The results from the trial will help to establish guidelines for use of the MERCI Retriever.


The MERCI Retriever

The only treatment currently approved by the FDA for acute stroke is a drug that can dissolve clots when administered intravenously, but it needs to be given within three hours from the onset of stroke symptoms. Unfortunately, very few ischemic stroke patients make it to a hospital within that time. However, Drs. Gobin and Leifer believe that the MERCI Retriever may benefit acute stroke patients when used up to eight hours after a stroke has occurred.

How the MERCI Retriever works:

After an ischemic stroke, doctors insert a catheter into a patient’s leg artery and, using the circulatory system as a pathway, guide it to the brain until the clot is reached. (view diagram of path)

At the clot, the Retriever is then deployed from inside the catheter and slowly rotated to ensnare the clot as a corkscrew would ensnare a cork. The MERCI Retriever – with the clot attached – is then retracted into the catheter, and the entire apparatus is withdrawn from the body. Pulling out the clot reopens the blood vessel and re-establishes blood flow into the brain.

Drs. Gobin and Leifer’s trial is officially known as "MR RESCUE" (Magnetic Resonance and Recanalization of Stroke Clots Using Embolectomy) and is funded by the National Institutes of Health (NIH).

Feel Like This? Get to an ER Fast.

Warning signs of stroke include sudden weakness or numbness on one side of the body; facial drooping; difficulty speaking; loss of balance or coordination; and difficulty seeing including sudden loss of vision or double vision. If you feel any of these symptoms, get to an emergency room as quickly as possible.

About the doctors:

Dr. Gobin is the director of Interventional Neuroradiology at NewYork-Presbyterian Hospital/Weill Cornell Medical Center. He is also a professor of radiology and a professor of radiology in neurological surgery at Weill Cornell Medical College. Dr. Gobin developed the original version of the MERCI Retriever in the 1990's.

Dr. Leifer is director of the Stroke Unit at NewYork-Presbyterian Hospital/Weill Cornell Medical Center. He is also an associate professor of neurology at Weill Cornell Medical College.