Ali Aziz-Sultan, MD
There are approximately 750-800,000 strokes per year, and they cause about 30% morbidity, mortality. More than 50 percent of the patients can't go back to work. It's a tremendous toll, not only on the patient, the family, but us in society. It costs billions of dollars to take care of these patients who are severely debilitated unfortunately from these problems.
The different types of strokes include both ischemic and hemorrhagic. Ischemic stroke is essentially a clot going up, wedging in one of the vessels in the brain, which stops the blood flow to that area of the brain. And essentially, that area of the brain slowly starts to die off and doesn't function anymore. Hemorrhagic stroke is also a problem with the vessels of the brain. But instead of a clot actually wedging and preventing blood flow, there's actually a blister or blood pressure where one of these vessels actually burst and cause bleeding in the brain. The majority of strokes are ischemic.
The symptoms include sudden deterioration in terms of weakness on one side of the body, difficulty speaking, facial droop, loss of sensation, and usually it's symmetric to one side or another side of the body. It's something that happens suddenly, and it doesn't go away. And as soon as that happens, it's very, very important to seek medical attention immediately.
Brigham and Women's Hospital, through our Telestroke System, we're actually alerted before the patients get to the hospital. And three teams are actually standing by waiting for the patient to arrive, including the emergency room medical doctors, the neurologists, the stroke neurologists in particular, and then the entire interventional team.
Ischemic strokes are treated in a number of ways, and essentially one of the first ways of treating them, if caught in a timely fashion, is to give patients intravenous TPA. This is a medication that actually lyses the clot and sort of dissolves the clot away. This can only be done within the first four-and-a-half hours of symptoms if the stroke hasn't involved. Beyond that, there're newer technologies where we can go in and actually remove the clot, break up the clot, or actually aspirate the clot.
So these catheters are actually taken through one of the femoral vessels and, within five minutes, taken up to the vessels in the brain. The catheter is actually brought to the clot. And then you deploy this net across this clot. This net on cross-section expands, integrates into this clot. Once the net has captured the clot, you inflate a balloon to stop any forward flow. And you aspirate, and you retrieve the catheter.
These devices are now opening up 90 percent of vessels, where before we were opening up 30 percent, just with giving IV TPA and giving intra-arterial TPA was opening up about 50 percent of vessels. So these procedures can be extremely quick, extremely safe, and it can have a dramatic impact on patients' lives.
One of the main causes of hemorrhagic strokes are aneurysms. Aneurysms is essentially a blister that forms on the side of a vessel, usually at a branching point, and it's essentially a weakness in one of the vessels in the brain.
And when aneurysms reach a certain size, they have a risk of rupturing. And when they rupture, they can cause a stroke. Fifty percent of patients die on the spot when an aneurysm ruptures. So the key is to diagnose these before they rupture, and to treat them.
The classic way of treating aneurysms is to do a craniotomy – open a small window through the skull and go through the folds of the brain. Not actually going through the brain, but across certain folds in the brain to get to the aneurysm and place a clip across the neck of the aneurysm and isolate it from the vasculature.
In the mid-'90s to late '90s, endovascular techniques were developed. And again, these are catheter-based techniques where we access the cerebrovasculature through the femoral artery, and we go through with a large, essentially a large IV-type catheter through one of the arteries, and we get to the vessels in the brain. Now we have flow diverters, which actually cause blood flow to go away from where the aneurysm is and cause shrinkage of aneurysms. Every five years or so there's a new type of technology that makes treating aneurysms safer and more efficient.
The future for both ischemic stroke and hemorrhagic stroke is essentially a closer integration, like we have here at Brigham and Women's, between the different services within the operating room.
For example, with ischemic stroke, the operating rooms that we have built here have the ability to not only remove clots, but we can actually diagnose them, essentially doing a CAT scan with a profusion scan in the operating room so that you don't have to go from the emergency room, to a CAT scan, to the operating room. You can actually skip a number of those steps and come straight to the operating room. And the importance of that is that you're saving very important time, which equates with brain tissue death.
As far as hemorrhagic stroke we've already been able to do a couple of patients in these hybrid approaches, where we're able to, for example, in an aneurysm, go through the vessels in the groin, an aneurysm that had ruptured, take care of the aneurysm through an endovascular route, and then open the head and remove the blood clot that was there. And we're able to do this in a very, very timely fashion, which is critical in these cases, all in one operating room with the same surgeon.
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