Mayo Clinic participates in nationwide stroke treatment study

Wednesday, June 27, 2001

JACKSONVILLE, Fla., June 27, 2001 — Physicians at Mayo Clinic in Jacksonville, Fla., will participate in a new, nationwide stroke treatment study. The study hopes to demonstrate that stroke victims who receive clot-dissolving medication intravenously and directly into the stroke-causing blood clot have a better chance of full recovery than those who only receive the drug intravenously.

In 1995 the National Institute of Neurological Disorders and Stroke (NINDS) reported the thrombolytic (clot-dissolving) drug, tissue plasminogen activator (t-PA), was an effective emergency treatment for acute ischemic stroke. Patients in that study who were given t-PA intravenously within three hours of the onset of stroke symptoms were at least 30 percent more likely to recover with little or no disability than those who were not treated with t-PA. In 1996, the Food and Drug Administration (FDA) approved t-PA as the first drug for treating acute ischemic stroke.

Other clinical trials have shown that giving thrombolytic drugs, including t-PA, directly into an artery (intra-arterial) is also an effective way to treat acute ischemic stroke.

Dr. Thomas Brott, a neurologist who participated in the NINDS study, will also be part of the new Interventional Management of Stroke (IMS) study. Now practicing at Mayo Clinic in Jacksonville, Brott explains why attempting thrombolysis (dissolving blood clots) two ways may further improve stroke recovery rates. "We can start intravenous thrombolysis very rapidly, and it's easy to do," he says. "The disadvantage is that it dissolves clots in only about 30 percent of the patients. Intra-arterial thrombolysis dissolves about 60 percent of the clots, but it takes much longer, and during that time, brain cells are dying by the thousands from the blockage that causes stroke. The IMS study is an attempt to combine the best of both techniques."

Dr. David Miller, a neuroradiologist at Mayo Clinic in Jacksonville, will also participate in the study. "We really don't know at this point the most effective way to deliver the drug," Miller says. "Time is always your enemy in treating stroke. We want to get the drug on board quickly, but we also want to get the drug directly to the clot. This may be a way to make up for the time lost getting a patient ready for angiography."

Stroke victims brought to St. Luke's Hospital in Jacksonville within three hours of the onset of their stroke symptoms may be eligible for the study treatment. They must not be taking certain blood-thinning medications, and a CT scan must show that their stroke is caused by a blocked artery (ischemic stroke) and not by a ruptured blood vessel (hemorrhagic stroke).

Eligible patients who consent to the treatment will be given two-thirds the normal dose of t-PA intravenously. In addition, an interventional team will insert a catheter into the patient's femoral artery, near the groin, in order to perform an angiogram (X-ray image of blood vessels). They'll maneuver the catheter to the blocked artery, and when the clot is located, doctors will inject t-PA directly into it. Brott says it may be that the intravenous t-PA will work to soften the clot before the intra-arterial t-PA takes over.

Stroke is the third leading cause of death in the United States and a leading cause of long-term disability. The NINDS believes only a small percentage of the 700,000 Americans who experience a stroke each year seek emergency treatment soon enough to benefit from t-PA. This is because many victims don't recognize their symptoms are due to a stroke. Sudden numbness or weakness of the face, arm or leg, and sudden difficulty speaking, seeing or walking are all stroke warning signs and should not be ignored. Anyone experiencing any of these symptoms should seek emergency treatment right away.

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Media contact: Erik Kaldor 904-953-2299 kaldor.erik@mayo.edu

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