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Tiny Vacuum Removes Blood Clots from the Brain
It's now possible to remove a blood clot from a stroke victim's brain by using a tiny vacuum cleaner. Initial results using the device have been encouraging.
About 80% of all strokes are caused by a blood clot in the brain. The clot interrupts blood flow to portions of the brain, and brain cells begin to die. The sooner the clot is removed, the fewer cells die. This improves survival rate and leads to better recovery from stroke symptoms such as paralysis and slurred speech.
The current treatment to remove clots is injection of the drug tPA, which chemically dissolves the clot. The drug must be administered within three hours of the stroke to achieve good results. The mini-vacuum may be effective for a longer period of time after stroke onset because it removes the clot immediately, while it takes some time after tPA is injected for the clot to actually dissolve. The vacuum also appears to cause less bleeding than tPA use does.
The device was used on 27 Calgary patients who had suffered massive strokes between January and October of 2009. It proved possible to remove the clot in 26 of these patients and normal blood flow was restored in 23 of them. It will take some time before the longer term results of the procedure can be evaluated.
Right now, use of the vacuum is fairly limited. It can only be used on stroke victims with very large clots. And it takes quite a bit of training before a doctor can properly use the device. It requires threading a tiny tube through a blood vessel in the patient's groin, all the way up to the neck. Then an even smaller tube is threaded from the neck into the brain near the blood clot. The vacuum is then threaded through both these tubes. It's much more complicated than vacuuming up the average dust ball.
It will take some time before use of the vacuum becomes more widespread. Not only do more surgeons need to be trained how to use it, imaging specialists also need to be trained. Effective use of the vacuum requires that a CT scan be first taken and interpreted, to determine if the stroke is due to a blood clot in the first place and whether the clot is a good candidate for vacuuming. But in time, vacuuming out strokes could become as common as tPA usage is today.
The results of the initial of use of the vacuum, called the Penumbra System of Continuous Aspiration Thrombectomy, were presented on June 8 at the first Canadian Stroke Congress. The Congress was held June 7-8, 2010 in Quebec City, Ontario, Canada.
June 17, 2010
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