Lasers offer new hope in treatment of strokes

February 10, 2000
Web posted at: 5:30 p.m. EST (2230 GMT)

From staff and wire reports

(CNN)-- The intense power of a laser has been test-fired into the brain arteries of stroke victims, and the results have been good -- blood clots instantly vaporizing and oxygen-rich blood returning to cells.

This first use of lasers to remove stroke-causing blood clots was reported Thursday at the International Stroke Conference in New Orleans.

"It looks very promising," said Dr. Wayne M. Clark of the Oregon Stroke Center in Portland. He led a team of researchers using the laser technique.

"But at this point, we're mainly studying the safety," he said. "We have achieved complete vessel re-opening in some patients, while in others, treatment was not possible due to difficulties getting to the clot with the laser-tipped catheter."

Clark said the next major advancement in acute treatment of stroke patients could be the physical removal of blood clots. Lasers, suction devices and tiny wires used as snares offer potential.

The only federally approved acute treatment for stroke caused by blood clots is a clot-dissolving medication sold under the name "Activase." It must be administered within three hours of the stroke to be effective.

"It's still very true that 'time is brain,'" said Clark. "But we hope that through treatments like this one (with lasers), we can provide a longer time window for stroke treatment."

Clark's study was based on experiences with the five patients receiving laser therapy. To be effective, the laser had to be used within eight to 24 hours of the stroke depending on where the blood clot was located. The study was done to determine the safety of the technique, but more research is needed to determine the long-term effectiveness of the technique, Clark said.

Team members used a laser-tipped catheter, threading it through blood vessels to the point of blockage. The tip had to be within a centimeter of the clot.

"The laser is activated, and the light is drawn only to the components of the blood clot, which is composed of various proteins, red-blood cells and other particles," said a spokesman for the American Stroke Association.

"Light and energy are only created where there is red -- the color of the clot -- not in the white walls of the vessel surrounding the clot," said the spokesman.

Clark added, "The light only causes energy when it hits something red. The laser will hit the clot and vaporize it."

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National Stroke Association
American Heart Association

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