Monday, August 16, 2004

New Stroke Treatment

Exciting news for stroke victims:
WASHINGTON -- The first device to remove blood clots from the brains of people suffering strokes — a new treatment option that could save lives and shave the $53 billion annual bill to treat strokes, has been approved by the government.

In 80 percent of strokes, a blood vessel in the brain becomes clogged by a blood clot, increasing the chance of severe disability or death.


The Merci Retriever, a tiny corkscrew threaded through an artery to remove the clot and restore blood flow, is produced by Mountain View, Calif.-based Concentric Medical.


The device, approved by the Food and Drug Adminstration, was tested at 25 medical centers around the nation in 141 patients ineligible for a drug that clears clots but must be used within three hours of suffering a stroke.

* * *

Duckwiler said the recovery included instantly regaining the ability to move or speak — while the patient was still in the emergency room.


"I've had patients who have had dramatic recovery on the table," he said. "Our neurologists there, and in the study, were convinced this is going to save lives and save brain function in many patients."

* * *

As part of the patient assessment, a catheter must be inserted through the groin and snaked up the artery for descriptive dye to outline blood vessels and point to obstruction, Goldstein said. The task requires skilled medical workers.


"It's not the kind of thing that is capable of being done in any hospital anywhere," Goldstein said. "The patient has to have a clot that is not only visible, but accessible. That is a major, major limitation to begin with."


Duckwiler agreed. But many patients don't qualify for the current treatment — a clot-busting drug — because too many hours pass before they recognize they've had a stroke. Some can't qualify because they're taking drugs that impact blood clotting.
* * *
Now for some skepticism.

As noted above, 80% of strokes are caused by clots. But the other 20% are caused by hemorrhages. I don't know, but I'd be willing to bet that this corkscrew treatment is absolutely contraindicated for hemorrhagic strokes, as it would probably increase the risk of a fatal bleed. (This is the same reason that hemorrhagic strokes are not treated with the "clot-busting" drug -- TPA, or tissue plasminogen activator.)

In fact, I'd bet that this treatment is contraindicated for the condition that I had -- a vertebral artery dissection. Recall that this means the inner wall of an artery has gotten a slight tear, peeling up slightly (forming a site where blood can clot). I'm not a doctor, but I have a pretty good guess that you don't want to be sticking a corkscrew into an artery that is already torn.

So the emergency room doctor would have to be sure that the stroke isn't hemorrhagic. How to be sure of that? A CT scan is absolutely necessary, for one thing, but even those aren't completely accurate. The doctor might need to order an MRA or lumbar puncture test to be sure.

Then, it appears that the corkscrew procedure will require a four-vessel angiogram, which is what the article talks about when it mentions a catheter "inserted through the groin and snaked up the artery for descriptive dye to outline blood vessels and point to obstruction." I've had this surgery, and it requires full anesthesia.

Now think about it: The stroke victim has to get to the hospital in the first place; and then be admitted; and then have one or more tests done to determine the nature of the stroke; then surgeons have to arrive to perform a four-vessel angiogram to determine where the clot is; and only then can the corkscrew procedure be done (assuming that the surgeons know how to do that procedure in the first place).

And the procedure can only be done within 3 hours of a stroke. I doubt that this is going to be logistically possible in most cases.

UPDATE: Apparently, the corkscrew procedure can be used up to eight hours after a stroke. This is good news, although I still think that it will be a long time before this procedure is any use to most stroke patients. (My own doctors didn't know that I had a dissection, for example, even after all the tests. It was only weeks later when I consulted a professor of stroke research in another state that this fact was revealed.).

2 Comments:

Anonymous Anonymous said...

Stuart, considering "[the drug] was tested at 25 medical centers around the nation in 141 patients ineligible for a drug that clears clots but must be used within three hours of suffering a stroke." and
"But many patients don't qualify for the current treatment — a clot-busting drug — because too many hours pass before they recognize they've had a stroke," I'd say that it's the drug, not the corkscrew, that has to take place within three hours. Otherwise it's bad copyediting and bad writing.

6:10 PM  
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