Is aspirin therapy beneficial for stroke prevention?

Almost everyone is familiar with aspirin. In fact, aspirin is one of the first commonly used medications. The herbal origins of aspirin, also known as acetylsalicylic acid, date back to ancient times. The compound was first registered as Aspirin in 1899. 

This inexpensive medication has long been used to reduce fever, joint pain and inflammation. Over time, aspirin therapy has been recognized for its role in stroke prevention.

Starting in the 1950s, medical researchers began studying aspirin's potential to prevent heart attacks and strokes. Over the next several decades, studies showed aspirin could be beneficial for people with cardiovascular disease. Doctors began recommending daily aspirin to help prevent strokes and heart attacks. More recently, however, research has shown that daily aspirin may not be appropriate for the general population.

Aspirin therapy for primary stroke prevention

While some people may benefit from taking a daily low-dose, or baby aspirin, you should never start aspirin therapy unless it is recommended by your doctor.

In 2022, the U.S. Preventive Services Task Force released an updated recommendation stating that adults age 60 or older should not begin taking daily aspirin to prevent a first-time, or primary, stroke or heart attack. For adults ages 40 to 59 who are at higher risk for cardiovascular disease, aspirin therapy should only be considered if a doctor determines the benefits of the drug outweigh the risks.

Because aspirin is so familiar, it can seem harmless. Like all medications, however, it has side effects. Aspirin thins the blood, which increases the risk of gastrointestinal bleeding, bleeding in the brain and kidney problems. While the overall risk of serious bleeding is low, aspirin is no longer recommended for people with no history of stroke who are not at high cardiovascular risk.

Daily aspirin is not recommended if:

• You have an allergy to aspirin
• You have a history of gastrointestinal bleeding
• You have a condition that increases your risk of bleeding
• You have been diagnosed with a clotting disorder
• You drink alcohol regularly, which can increase the risk of stomach bleeding
• You take medications, herbals or dietary supplements that may interact with aspirin

Aspirin for secondary stroke prevention

Aspirin is an important therapy for preventing a second stroke in people who have already experienced a stroke caused by blood clots. There are two main types of strokes. 

An ischemic stroke occurs when a blood clot blocks or reduces blood flow to the brain. About 87% of strokes are ischemic. Aspirin can be helpful if taken within 48 hours of an ischemic stroke, once imaging confirms the stroke type. Daily aspirin is also commonly prescribed after a heart attack or ischemic stroke. Research shows that for people with a history of ischemic stroke, aspirin therapy can reduce the risk of having another one. In these cases, the benefits of aspirin therapy generally outweigh the small risk of bleeding.

A hemorrhagic stroke occurs when a weakened blood vessel in the brain ruptures and bleeds. Aspirin is not recommended for hemorrhagic stroke because it can worsen bleeding. Because the type of stroke cannot be determined without medical testing such as a CT scan, you should not take aspirin during a suspected stroke. After evaluation, your doctor will decide whether aspirin therapy is right for you. 

Aspirin use in cardiovascular conditions

Daily or low-dose aspirin may be prescribed if you have angina, have had bypass surgery, have a cardiac stent or have reduced blood flow to the brain. It may also be recommended if you have diabetes along with another risk factor for heart disease, such as smoking or high blood pressure.

How aspirin therapy helps prevent stroke

Platelets are tiny blood cells that help the body form clots. When a blood vessel is damaged, platelets rush to the area and become sticky, clumping together to stop bleeding.  If a clot forms in a vessel that carries blood to the brain, a stroke can occur.

Strokes can also be caused by plaque buildup from atherosclerosis. Plaque is made of fat, cholesterol, calcium and other substances that are collected in the artery walls. Over time, plaque narrows the arteries and limits blood flow. If plaques rupture, a clot can develop and travel to the brain, blocking oxygen.

Aspirin works by making platelets less sticky, which helps prevent clots from forming. It may also slow the progression of atherosclerosis. After a stroke, if your doctor determines aspirin would be beneficial, it may be prescribed for months or even years as part of your ongoing care.

Stroke prevention through lifestyle changes

Up to 80% of strokes can be prevented through healthy lifestyle choices, and it is never too early to start. About 15% of strokes occur in adults age 50 or younger. Small changes can make a meaningful difference at any age.

Ways to lower your stroke risk include:

• Stop smoking. Smoking thickens your blood and increases plaque buildup in the arteries. According to the U.S. Centers for Disease Control and Prevention (CDC), for every five cigarettes smoked per day, stroke risk increases by 12%.
• Manage blood pressure. High blood pressure is the leading cause of stroke. A healthy diet, regular exercise, maintaining a healthy weight and taking medications as prescribed can help keep blood pressure under control.
• Move more. Aim for at least 30 minutes of moderate physical activity five days a week. A daily walk is a good place to start.
• Limit alcohol to one drink a day or less.
• Improve your diet. Eat more fruits, vegetables, whole grains, fish and nuts, and limit foods high in saturated fats and cholesterol.

If you or a loved one is recovering from a stroke, specialized stroke rehabilitation care can support recovery and help reduce future risk.