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Advances in Treatment of Cerebral Arterial Thrombosis: the Thrombectomy Device


About twenty percent of the 800,000 patients a year in the United States who have strokes are affected by acute cerebral thrombosis, that is, a clot fills up an artery that feeds a part of the brain and stops blow flow, resulting in death of the affected brain region and loss of function: a stroke.  That implies that the affected brain region is, during the early phase of stroke onset, revivable if blood flow can be restored.

Some years ago(here in 1995), a drug called tPA (plasminogen activator) was developed that could dissolve the blood clot in some instances.  This was only partially effective.  Over the last few years(here in 2007), a basket-like expandable intra-arterial catheter has been developed that can be introduced through a groin incision all the way up to the cerebral arteries.  This device can be inserted up to the clot; a central wire then punctures the clot, and a basket-like surrounding wire is expanded around the clot.  The whole can be retrieved through the groin incision.

The use of the clot extractor has been aided by improvements in brain imaging and catheter technology generally that make the whole procedure simpler and safer.

Some five trials have been recently performed of this device compared with tPA; four were stopped early because of the benefits of the device.  Patients assigned to the device arm had 60 to 75 percent functional recovery, as opposed to only 40 percent recovery with tPA alone.  These results are a dramatic improvement over tPA, which was itself considered a breakthrough when it was revealed.

Even more impressive is the window for successful treatment of an acute stroke, which has widened to nearly six hours when the device is used.

The treatments are also complementary.  The clot retriever is good for large clots, and tPA is good for smaller clots, such as those that break off when the clot retriever is closed on a large clot.

One aspect of the treatment has not been explained: the results are much better if the patient is awake when the device is being used.  Whether it is the fact that the patient is in better condition overall when they can be kept awake or whether there is another explanation has not yet been explored.

The article I’m referring to is in Science News; the most recent of the five trials mentioned above was published in March in the New England Journal of Medicine, here.  Unfortunately, the Science News is on a pay list and the New England Journal articles are only available as abstracts unless you want to pay to subscribe.

So you have to read between the lines and get the information from another source that this is going to be the preferred therapy for large, acute strokes of recent onset: to put them under some sort of brain vascular scanning to look for an arterial blood clot, and if the symptoms are less than twelve or twenty four hours old, use the “thrombectomy” device, possibly followed by tPA.

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