Experimental device shows promise against devastating strokes
Monday, October 20th 2003, 12:00 am
News On 6
WASHINGTON (AP) _ One minute Gary Formanek was hitting balls at an Oregon driving range. The next, he was lying on the ground, his left side paralyzed from a stroke.
The only drug that treats strokes didn't help. So doctors snaked a tiny corkscrew into Formanek's brain and pulled out the stroke-causing clot.
The device that saved Formanek from disability, if not death, is generating excitement among brain experts who say the novel technology might finally offer hope for the most devastating strokes.
Called the MERCI Retriever, it's still experimental. But in early testing, it seems to restore blood flow in almost half of patients _ people who couldn't be helped by today's only stroke-busting medication.
``We know the limits of current stroke therapy,'' says Dr. Vance Watson of Georgetown University Hospital, who pulled pea-sized clots out of a woman near death from a massive stroke after childbirth. The woman still has some arm weakness, but has largely recovered.
``You wouldn't get this result without this device. She was lucky,'' Watson says.
Dr. Sidney Starkman of the University of California, Los Angeles, recalls the first patient ever treated. Five usually staid doctors jumped up and down and high-fived as a man completely paralyzed for six hours began speaking on the operating table.
``It still brings chills to me,'' Starkman says.
More than 700,000 Americans will suffer strokes this year. Strokes are the nation's No. 3 killer, and the top cause of disability.
Some strokes are caused by bleeding in the brain. But the vast majority are ischemic strokes, caused when arteries feeding the brain are blocked. For those, the clot-busting drug TPA can mean the difference between permanent brain injury or recovery _ but only if given within three hours of the first symptoms. Less than 5 percent of victims get TPA because they don't get specialized care in time or the clot is too big for TPA to bust.
Enter the MERCI Retriever, invented by UCLA scientists and licensed to Concentric Medical of Mountain View, Calif. The hope is that it will work as late as eight hours after a stroke hits, and pull out bigger clots.
How? Specialists called interventional neuroradiologists thread a tiny tube inside a blood vessel at the groin and push it up the body and into the brain. Inside is a wire made of nitinol, a shape-remembering alloy, that promptly coils into a corkscrew shape as it's pushed out of the tube at the stroke's epicenter.
Pushed through the spongy clot, the twisted wire grips tight, like a corkscrew grips a wine cork. A tiny balloon inflates to temporarily stop blood flow _ avoiding a second stroke if a piece breaks off the clot before it's removed. Doctors then gently tug backward on the wire until the clog dislodges and is sucked inside the tube.
The main concern is puncturing an artery, considered a very rare risk.
Scientists have long tried to create mechanical clot-busters: lasers to cut channels through the blockage; balloons to press open clots like cardiologists use in the heart; suction devices.
So far, each has problems. They're hard to fit through tiny, twisting brain arteries, and brain clots, which have the spongy consistency of a canned peach, can't just be pushed aside like harder plaque that causes heart attacks.
Concentric's retriever is furthest along in testing. Results of a study of 125 patients ineligible for TPA, conducted at some of the country's largest stroke centers, are due in February.
Even if the device ultimately is approved for wider use, how well patients will do depends on how quickly they're treated. Delays can mean suffering too much brain damage to survive even if the clot is removed.
So, immediately get to a hospital known for treating strokes if you have symptoms: weakness or numbness on one side, slurred speech, sudden confusion, trouble walking, loss of balance, sudden severe headache.
``It's not hopeless. Don't lay around at home hoping you're going to get better,'' says Georgetown's Watson, who is frustrated that many victims reach him too late even to try the MERCI Retriever.
Formanek is grateful that his local emergency room knew Oregon Health Sciences Center was testing the clot buster and raced him there.
``I really do appreciate that somebody had the guts to think through this procedure and do it,'' says Formanek, 64, of Forest Grove, Ore.
Ten days after his stroke, with a little lingering weakness, he golfed again. ``My score hasn't improved but ... every shot there is a blessing whether it's good or bad.''