Lt. Gov. John Fetterman’s recovery from a stroke and his long-term health prospects depend on a variety of factors — chief among them how quickly the blockage was removed.

The Democratic candidate for U.S. Senate was diagnosed on Friday with the stroke, a blood clot that had blocked a major artery in his brain, and physicians removed the clot the same day.

So far, Fetterman’s campaign has said only that he got to Penn Medicine Lancaster General Hospital “quickly,” and that he suffered no cognitive damage. Fetterman, who is leading his fellow Democrats in the polls, is planning to skip Tuesday’s election-night rally as he focuses on his recovery.

For a rundown on strokes and the type of procedure Fetterman had, we spoke to Thana Theofanis, an endovascular neurosurgeon with Main Line Health-Jefferson Neurosurgery, and Carole Thomas, medical director of the stroke program for Virtua Health in South Jersey.

The two physicians were not involved in Fetterman’s care and could not comment on the specifics of his case, but they described generally how the procedure, called a thrombectomy, can lead to a full recovery if all goes well.

What type of stroke did Fetterman have?

There are two kinds of strokes. One is a hemorrhagic stroke — bleeding in the brain — from a ruptured blood vessel.

Fetterman had the other kind, called an ischemic stroke. That means a blood clot blocked one of the large vessels that supplies oxygenated blood to the brain.

When brain cells are starved of oxygen, they start to die. The sooner the condition is diagnosed and treated, the more brain cells can be saved, Theofanis said.

“Literally minutes matter with this,” she said.

How common is a stroke in your 50s?

More common than you might think. For white men ages 45 to 54, the chance of a stroke in a given year is 2.4 out of 1,000, according to the American Heart Association.

In other words, every year, 1 out of 400 people in that demographic group will have a stroke. Fetterman is 52.

And the odds for Black men in that age group are four times as high — roughly 1 in 100.

Luke Perry, the actor best known for Beverly Hills 90210, died of a stroke at Fetterman’s age in 2019.

Director, producer, and screenwriter John Singleton, best known for Boyz N the Hood and Snowfall, died of a stroke later the same year, at age 51.

How did doctors treat Fetterman’s stroke?

The politician underwent a thrombectomy. That means physicians inserted a catheter into an artery in his groin or wrist, carefully snaking it up all the way to his brain.

These catheters can be used to remove such clots in one of two ways, or sometimes both, depending on the patient’s circumstances, said Theofanis, who performs thrombectomies at Bryn Mawr Hospital.

The catheter can be used to deploy a stent retriever, a mesh tube that grabs hold of the clot so it can be pulled out. Or physicians may opt to aspirate the clot and remove it with gentle suction, she said.

For patients who are diagnosed within 4.5 hours of the stroke, physicians may also administer a clot-busting drug called tissue plasminogen activator, said Thomas, a neurologist at Virtua.

Could Fetterman have long-term complications?

Again, timing is everything.

Physicians used to perform thrombectomies only if they got started within 4 to 6 hours of the stroke, Theofanis said.

But in the past decade, studies have found that the procedure can be helpful even up to 24 hours after the stroke.

A radiologist uses a special type of CT scan to identify which portions of the brain have suffered irreversible injury, and which may still be salvageable, Theofanis said.

“Even if we can’t prevent the entire brain from having a stroke, we try to prevent a catastrophic stroke and save that area at risk,” she said.

Every patient is different. But if a thrombectomy is performed within hours of a stroke, patients can make a full neurological recovery, she said.

Some patients have lingering symptoms, such as weakness on one side of the body, but with physical therapy, they can remain independent, Thomas said.

What causes a stroke?

An ischemic stroke — the kind caused by a blood clot — can result from a mix of lifestyle and hereditary factors.

Among the risk factors are those that can contribute to cardiovascular disease anywhere in the body: diabetes, obesity, smoking, high cholesterol, and high blood pressure.

Fetterman once weighed more than 400 pounds — squarely in the obese category for someone of his height, 6-foot-8 — before losing nearly 150 pounds in 2018.

His current weight has not been disclosed, but if it remains close to that level, he would still be classified as overweight.

Another risk factor for stroke is COVID-19, as the disease can lead to abnormal formation of blood clots. But Fetterman is vaccinated and boosted, meaning his risk of severe outcomes from COVID is low.

How does a-fib lead to a stroke?

Fetterman’s campaign said his stroke was the result of an irregular heart rhythm called atrial fibrillation, commonly called “a-fib.”

The heart’s left atrium quivers with each beat, which can disrupt blood flow in a pouchlike attachment called the left atrial appendage. The temporary stagnation of blood flow in this appendage is what raises the risk of blood clots, Thomas said.

“It just makes it easier for clots to form, because you’re not flushing it out with every heartbeat,” she said.

When a clot forms and travels to the brain, that’s the definition of a stroke.

People with a-fib are sometimes advised to take anticoagulants — blood thinners — to reduce the risk of stroke.

Asked how long Fetterman had been aware of his a-fib, and whether he was taking such a medicine, the campaign did not immediately respond.

Signs of a-fib can include palpitations, shortness of breath, and unexplained fatigue.

How can I tell if I’m having a stroke?

A good way to remember the signs of stroke is the acronym FAST, which stands for facial drooping, arm weakness, and speech difficulty. If any of those indicators are present, proceed to the letter T: Time to call 911.

Other signs may include sudden onset of any of the following: confusion, severe headache, dizziness, or numbness in the face, arm, or leg.

Some of these symptoms can, of course, have other causes. The time to worry about a stroke is when they come on suddenly, Thomas said.

“You’re perfect, and then you’re not,” she said.

And the symptoms need not be severe, Theofanis said.

“Even something small — some subtle, slurred speech, dizziness, feeling off balance, a slight facial droop — these things could mean you’re having even a mini-stroke and have reason to seek medical care,” Theofanis said.

Staff writer Julia Terruso contributed to this article.