The Short Window for Ischemic Stroke Treatment: Why Moving Fast Matters

The time that stroke symptoms begin is critical information for doctors.

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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.”