Tiny Corkscrews To Prevent Strokes

A tiny corkscrew that spears blood clots lodged deep within the brain appears to be a promising new tool for stopping strokes.

A doctor who tested the approach said Thursday that in some cases, it immediately reversed paralysis and loss of speech when used in the first hours of a stroke.

Nearly 90 percent of all strokes result from clots that block the brain's arteries, cutting off circulation and starving brain cells. The goal of the new device is to extract these clots before they do permanent harm.

"It's like pulling the cork out of a wine bottle," said Dr. Sidney Starkman, co-director of the UCLA Stroke Center. "What you want is to get the blood flowing back to the brain."

The device is the most advanced of several new stroke treatment tools discussed at a meeting in San Diego of the American Stroke Association.

The only treatment now available for the emergency care of strokes is TPA, the clot-dissolving medicine also used to stop heart attacks. Only about 5 percent of stroke victims receive it, and among those, it helps only about one in eight.

TPA can be used only within the first three hours after a stroke. Most victims arrive at the hospital too late, or they have other conditions that could cause the TPA to trigger disastrous bleeding in the brain.

Starkman directed testing of the corkscrew — called the Merci Retrieval System — on 109 patients. All had suffered severe strokes within the previous eight hours, and none could be given TPA.

The corkscrew successfully retrieved the clot in half of them. Three-quarters of these patients survived, and 40 percent had few or no lasting disability. Among those in whom the clot could not be removed, half survived and just 6 percent had a good recovery.

Starkman said many of the patients were paralyzed on one side or could not talk when the procedure began.

"What's really remarkable is we can see the problem and pull it out," he said. "In some patients, the moment the clot came out, they could move again or talk normally. It was instantaneous."

Starkman's study was financed by the corkscrew's maker, Concentric Medical of Mountain View, Calif. Based on this study, the company has asked the Food and Drug Administration for approval to sell the device. An FDA advisory committee will review it later this month.

The National Institutes of Health will sponsor a larger study of the device. Patients will be randomly assigned to get either the corkscrew or routine care.

Dr. Larry Goldstein, head of the cerebrovascular center at Duke University, said patients who got the corkscrew appeared to do better than expected. However, he cautioned that the many patients whose clots do not show up on brain scans would not be eligible for the treatment.

"It won't be a panacea," he said.

Another drawback is that it can be done only by specially trained neuroradiologists. A UCLA survey found that 82 percent of the population lives within a three-hour drive of a hospital that could do the procedure.

Dr. Morgan S. Campbell of the Alabama Neurological Institute in Birmingham presented preliminary results of another approach intended to improve circulation to the brain after a stroke. The treatment involves inflating balloons in the abdominal aorta, forcing more blood to the head.

The initial safety testing showed improved cerebral blood flow in 12 of 16 patients. The device, called NeuroFlo, was developed of CoAxia of Maple Grove, Minn.

Other researchers described initial testing of liquid-cooled helmets, intended to lower the brain's temperature to minimize damage following a stroke.

"It's like a very fancy icepack," said Dr. Huan Wang of the University of Illinois.

In testing on six patients, Wang's helmet cooled the brain an average of six degrees in the first hour without significantly lowering body temperature. He said it might be used in the ambulance to protect patients' brains until they can receive other treatment.

By Daniel Q. Haney