Aspirin: It’s Not an Ounce of Prevention

You should not take daily low-dose aspirin on your own without talking to your doctor.

For decades, a daily dose of aspirin was considered an easy way to prevent a heart attack, stroke or other cardiovascular event.

Recently, though, a string of studies are challenging that assumption. With this latest research in mind, a new set of heart health guidelines advising against daily aspirin use for prevention were issued jointly by the American College of Cardiology (ACC) and the American Heart Association (AHA). The two groups agree that for older adults at low risk – no history of heart attack, stroke or cardiac surgeries – the risk of bleeding that comes with daily low-dose aspirin (typically 81 milligrams) is now thought to outweigh any heart benefit. That means that it may actually cause more harm than good.

“We’re talking about healthy people who don’t have known heart disease or stroke risk, who might have been considering or are already taking an aspirin to prevent that heart attack or stroke in the first place,” said Dr. Erin Michos, one of the writers of the new guidelines.

The AHA and ACC stressed that daily aspirin does have an important role to play for people at high risk – those with a prior history of heart attack, stroke or cardiac procedures such as stenting or open-heart surgery. In those cases, daily use of the blood-thinning pill “can be lifesaving,” the groups said.

The Studies

According to three significant studies published last year and one major analysis released this year that looked at 10 other studies, the benefit from taking a daily low-dose aspirin was offset by the danger of internal bleeding and other side effects in people considered to be at low or moderate risk for heart disease. One study in particular found aspirin had no obvious benefit for healthy people older than 70, but did find evidence for harm.

“Clinicians should be very selective in prescribing aspirin for people without known cardiovascular disease,” Dr. Roger Blumenthal, co-chair of the 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease and professor of cardiology at Johns Hopkins Medicine in Baltimore, said in a statement. “It’s much more important to optimize lifestyle habits and control blood pressure and cholesterol as opposed to recommending aspirin.

Why the Change?

In addition to the research, we are now much better at treating risk factors such as hypertension, diabetes and especially high cholesterol. The guidelines do state that people who find they have trouble lowering their high cholesterol or controlling their blood sugar might also be considered for daily low-dose aspirin, as long as their risk for bleeding doesn’t outweigh any potential benefit.

“The most important way to prevent cardiovascular disease, whether it’s a build-up of plaque in the arteries, heart attack, stroke, heart failure or issues with how the heart contracts and pumps blood to the rest of the body, is by adopting lifetime heart healthy habits,” Blumenthal said. That includes staying away from smoking, secondhand smoke and vaping. It also means sticking to heart-healthy diets that focus on fruits, vegetables, nuts, whole grains and fish. Intake of salt, saturated fats, fried foods, processed meats and sugary beverages should all be kept to a minimum. Including 150 minutes per week of moderate-intensity exercise (brisk walking, swimming, dancing or biking, for example) is recommended, as is maintaining a healthy weight.

And what about cholesterol? Healthy living helps keep arteries clear, but if more help is needed, statins might be recommended. “Statins should be recommended along with lifestyle changes to prevent cardiovascular disease among people with elevated low density lipoprotein [LDL] cholesterol levels at or above 190 mg/dl,” the two groups explained in the statement. Statins may also be indicated for people with type 2 diabetes and anyone who is deemed to have a high likelihood of having a stroke or heart attack based on their medical history and risk factors.

Know the Risks

Because aspirin thins the blood, it can cause several complications. Tell your doctor if any of these situations apply to you. You should not take daily low-dose aspirin without talking to a doctor if you:

• Have an aspirin allergy or intolerance
• Are at risk for gastrointestinal bleeding or hemorrhagic stroke
• Drink alcohol regularly
• Are undergoing any simple medical or dental procedures
• Are over the age of 70

There is a risk of stomach problems, including stomach bleeding, for people who take aspirin regularly. Alcohol use can increase these stomach risks. If you are told to take aspirin, ask your doctor if it is safe for you to drink alcohol in moderation.

How does aspirin help prevent heart attack and stroke?

Most heart attacks and strokes occur when the blood supply to a part of your heart muscle or brain is blocked. This usually starts with atherosclerosis, a process in which deposits of fatty substances, cholesterol, cellular waste products, calcium and other substances build up in the inner lining of an artery. This buildup is called plaque.

Plaque usually affects large and medium-sized arteries. Plaques can grow large enough to significantly reduce the blood’s flow through an artery. But most of the damage occurs when a plaque becomes fragile and ruptures. Plaques that rupture cause blood clots to form that can block blood flow or break off and travel to another part of the body. This is called an embolism.

• If a blood clot blocks a blood vessel that feeds the heart, it causes a heart attack.
• If a blood clot blocks a blood vessel that feeds the brain, it causes a stroke.

Aspirin thins the blood, which helps prevent blood clots from forming.

Should I take aspirin during a heart attack or stroke?

The most important thing to do if any heart attack warning signs occur is to call 9-1-1 immediately. Don’t do anything before calling 9-1-1. In particular, don’t take an aspirin, then wait for it to relieve your pain. Aspirin won’t treat your heart attack by itself.

Taking aspirin isn’t advised during a stroke, because not all strokes are caused by blood clots. Most strokes are caused by clots, but some are caused by ruptured blood vessels. Taking aspirin could potentially make these bleeding strokes more severe.

What’s the bottom line?

The best way to know if you can benefit from aspirin therapy is to ask your health care provider. You should not start aspirin on your own.