The time that stroke symptoms begin is critical information for doctors.
Diagnosing a stroke is a bit like spilling red wine on white carpet. If you catch it immediately, you can grab the glass before too much has spilled, and you can blot out the dark red hue with a wet paper towel and a stain remover; it might not even leave a stain.
But if the spill goes unnoticed for too long, you’ll have a larger issue to deal with. More of the carpet will be affected, and the red wine might be harder to remove from the carpet. Even with the best stain-removing product, that red circle may be slightly visible for the rest of the carpet’s existence.
A stroke is an injury to the brain that can damage brain cells and cause lasting cognitive, physical, and emotional changes. For every minute that a stroke goes untreated, almost 2 million neurons and 14 billion synapses are damaged, according to a study in the journal Stroke. Learn more about how stroke affects the brain here.
“We know that time is key in terms of treating the brain and promoting good recovery,” says Carolyn Brockington, MD, neurologist at Mount Sinai Hospital.
The Window for Ischemic Stroke Treatment
If you’re having a stroke—or you see someone having a stroke—the most important thing to do is to call 911 and get professional treatment ASAP. Find out how to use the acronym F-A-S-T to recognize the signs of stroke.
The sooner you are able to reach the hospital and begin treatment, the better. Someone who arrives within an hour of stroke onset is going to receive different treatment (and have statistically better outcomes) than someone who arrives at the hospital several days after the stroke, according to Dr. Brockington.
“The FDA-approved treatment for acute ischemic stroke is tPA: tissue plasminogen activator,” says Dr. Brockington. “It essentially is a blood thinner to restore the blood flow that has reduced to the brain caused by the stroke.” (Learn more here about the difference between ischemic stroke and hemorrhagic stroke.)
Treatment with tPA is called the “gold standard” by the American Stroke Association; it offers the “best possible chance at a full recovery.” However, in order for tPA to be effective, doctors must administer it within a few hours of the start of stroke symptoms. For this reason, many people refer to ideal stroke treatment as the “three-hour window.”
Three hours for starting tPA is ideal, but some organizations are testing the efficacy of tPA administered beyond that window. “Sometimes we can extend the time period to four and a half hours,” says Dr. Brockington. “That’s for very select patients.”
Eligibility for Stroke Treatment
In addition to using the three-hour window, doctors who respond to stroke also consider a checklist of “exclusion criteria” for deciding if a patient is eligible for tPA treatment. “There are some situations where we can’t give people tPA,” says Dr. Brockington.
Some factors that may exclude someone from receiving tPA include very high blood pressure, having a recent head injury, having an aneurysm, or being on strong blood thinners, according to the American Heart Association. Even if these patients arrive in the hospital within the three-hour window, they won’t be able to receive tPA because the risks of getting the drug outweigh possible benefits.
Endovascular Therapy: An Alternative to tPA for Ischemic Stroke Treatment
For those who can’t receive tPA—either because they meet exclusion criteria or because they arrived at the hospital after the window of opportunity—a new treatment option may help. This is called endovascular therapy.
Here’s how endovascular therapy works: “We can actually go into the blood vessels of the brain and pull the clot out,” says Dr. Brockington. It can be given up to six hours, or possibly longer, after stroke onset.
First, doctors use an angiogram, an imaging method that shows a “map” of the blood vessels of the brain. Doctors can then insert a catheter through blood vessels in the groin and up to the blocked artery in the brain. Then, doctors can remove the clot using stents and possibly suction tubes, according to the American Heart Association.
“What we’ve found out in recent trials is some people with very large strokes [and] a lot of symptoms—if we get them in right away and are able to take the clot out of the artery—they can have minimal to no deficits,” says Dr. Brockington.
Although stroke treatment options continue to improve, the original message remains the same: “Coming in right away is key,” says Dr. Brockington. “Doctors are going to be able to determine which treatment you’re eligible for.”
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We know that time is key in
terms of treating the brain and
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promoting good recovery.
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Someone comes in right away,
within 30 minutes, an hour,
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and they've just had stroke symptoms.
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The treatment is different, because we're
trying to restore blood flow to the brain,
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in a very limited time.
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Versus someone who comes in several
days after they've had a stroke.
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That treatment is gonna be different,
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because the brain has
already been injured.
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The FDA approved treatment for
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acute ischemic stroke is tPA,
Tissue Plasminogen Activator.
00:00:36,770 --> 00:00:39,380
It essentially is a blood
thinner to restore,
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the blood flow that has been reduced
to the brain, causing the stroke.
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And that time or
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the time that we can give it,
is within three hours of symptom onset.
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Sometimes we can extend the time
period to four and a half hours.
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That's for very select patients, but
really it is within three to four and
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a half hours for IV tPA.
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There's some situations where
we can't give people tPA,
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and that is determined by
a lot of different factors.
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If they're on very strong
blood thinners already.
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If they've had a recent head injury,
if they've had recent surgery,
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if they have problems with their
blood where they don't clot well.
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So what's interesting is,
there's been a new game changer in stroke,
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in addition to giving a very
strong blood thinner.
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Many times we can actually go into
the blood vessels of the brain, and
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pull the clot out.
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It sounds like science fiction, but
it actually is true, and very effective.
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An angiogram is done, and
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an angiogram means that we
are mapping out the blood vessels.
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So a small catheter is
placed in the groin artery.
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And under x-rays we're able to see
all the blood vessels in the body.
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The catheter goes into the blood vessel
that is occluded, or narrowed, and
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tries to take the clot out of
the blood vessel through the catheter,
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and then pull it out of the body,
so it really is phenomenal.
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What we found out in recent trials is,
that with some people with very large
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strokes are coming in with a lot of
symptoms, that if we get them in
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right away, and we're able to
take the clot out of the artery,
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that they can have minimal or no deficits.
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The time perid for endovascular therapy,
could be six hours after symptom onset or
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it can be longer, but
it really depends on the person.
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And the longer you wait, the more
likely that that is not appropriate.
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So really coming in right away is key,
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are gonna be able to determine which
treatment you're eligible for.
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Del Zoppo GJ, Saver JL, Jauch EC, Adams HP. Expansion of the time window for treatment of acute ischemic stroke with intravenous tissue plasminogen activator. Stroke. 2009;40:2945-8.
Demaerschalk BM, Kleindorfer DO, Adeoye OM, Demchuk AM, Fugate JE, Grotta JC, et al. Scientific rationale for the inclusion and exclusion criteria for intravenous alteplase in acute ischemic stroke. Stroke. 2016 Feb.
Guidelines urge new approach to treating worst strokes. Dallas, TX: American Heart Association. (Accessed on June 4, 2018 at https://news.heart.org/guidelines-urge-new-approach-to-treating-worst-strokes/.)
Saver JL. Time is brain—quantified. Stroke. 2006;37:263-6.
Stroke treatment. Dallas, TX: American Stroke Association. (Accessed on June 4, 2018 at https://www.strokeassociation.org/STROKEORG/AboutStroke/Treatment/Stroke-Treatment_UCM_492017_SubHomePage.jsp.)