Stroke: Don't Dismiss Warning Signs

BIDMC Contributor

MAY 20, 2020

A woman is suffering from a headache.With many of our routines recently disrupted by the COVID-19 virus, it can be hard to know what's normal. Is a severe headache a response to stress or anxiety - or something more serious? Dismissing symptoms can have serious consequences, especially for individuals at risk for stroke. People with a family history of stroke or certain medical conditions need to be aware of the warning signs, which include sudden:

  • Weakness or numbness of the face, arm or leg, especially if it's confined to one side of the body
  • Confusion, trouble speaking or understanding
  • Trouble seeing in one or both eyes
  • Trouble walking, dizziness, loss of balance or coordination
  • Severe headache with no known cause

"We want to remind our patients that any of these symptoms could be signs of an emergency and should never be ignored," says Peter Zimetbaum, MD, Associate Chief of Cardiovascular Medicine and Director of Clinical Cardiology and Electrophysiology, at Beth Israel Deaconess Medical Center (BIDMC). "Patients may be worried about coming to the emergency room for fear of the COVID-19 virus. We can assure you that our facilities are safe and that it is much more dangerous to put off treatment of a stroke. Always call 9-1-1 if you experience any of these warning signs."

Atrial Fibrillation: A Leading Cause of Stroke

Atrial fibrillation (often called AFib) is one of the most common sources of ischemic strokes, which occur when a blood vessel supplying blood to the brain becomes blocked, explains Alec Schmaier, MD, a cardiologist specializing in vascular medicine at BIDMC. "Atrial fibrillation is a type of heart rhythm disturbance that prevents the heart's upper chambers [the atria] from contracting normally and can lead to the formation of blood clots. These clots can then break off and lodge in a vessel that supplies blood to the brain, causing a stroke.

"Patients who have been diagnosed with atrial fibrillation will often be prescribed an anticoagulant medication," says Schmaier. "In fact, anticoagulation is the most important tool we have to prevent stroke."


There are several types of anticoagulants (blood thinners) available. These include warfarin, which has been in existence for more than 60 years, as well as a newer class of drugs, direct oral anticoagulants (DOACs), which have been on the market for about 10 years.

"There are pros and cons for both types of anticoagulants," says Schmaier. "Warfarin is highly effective, but requires that patients keep track of their diets and have blood testing on a regular basis to ensure that warfarin activity remains steady." DOACs, on the other hand, do not require monitoring and have fewer dietary interactions.

"Doctors always strive to determine a patient's bleeding risk before prescribing an anticoagulant," says Schmaier. "We then carefully assess the risk of bleeding with the risk of stroke to determine which anticoagulation plan is best for each individual.

"If patients with atrial fibrillation have been successfully tolerating warfarin for a long time, I might recommend they stick with the drug," says Schmaier, adding that many patients who take warfarin appreciate the reassurance of their routine blood monitoring. "For patients who are just starting to use anticoagulants, I usually recommend DOACs."

Long-Term Treatment

How long does anticoagulation treatment last? "The goal of anticoagulation is to provide long-term stroke prevention," says Schmaier. "Therefore, patients who have atrial fibrillation will usually need to take anticoagulants throughout their lives to prevent stroke."

As a physician-scientist, Schamier’s research is focused on better understand the role of the endothelial cells lining the blood vessels, to identify the roots of blood clot formation. "Many of the inflammatory conditions that put a person at risk for developing AFib, such as high blood pressure and diabetes, can also increase the risk of blood clots," he explains. "Endothelial cells function as a natural anticoagulant, but inflammation causes these cells to behave differently, so that instead of preventing blood clots, they promote the formation of blood clots. As researchers, we are trying to understand how this change occurs and identify the genes responsible for this process."

For patients with AFib who cannot tolerate anticoagulation, other treatment options are available. These include a minimally invasive procedure known as left atrial appendage occlusion, in which a tiny device is implanted at the opening of the left atrial appendage where blood clots tend to form, thereby preventing clots from escaping and reaching the brain. "Doctors are continuing to learn more about AFib," says Schmaier. "As we know more, we will be better able to inform patients about their risk of stroke and ensure that their blood-thinning medications are safe and well-tolerated," he adds.

Above content provided by the CardioVascular Institute at Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.
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