Medications to prevent or treat blood clots and stroke include blood thinners, also called anticoagulants.
Blood thinners work by reducing the ability of the blood to clot. But as with all medications, blood thinners have side effects. In preventing blood clots from forming, there is also a higher chance for bleeding in some people. Usually, the bleeding is minor – for example, bruising more easily, or having a nosebleed or cut that takes longer to stop bleeding. However, some bleeding can be serious.
For many patients, the benefits of taking a blood thinner far outweigh the risk of bleeding, according to cardiologists. Even when bleeding does occur, it can usually be managed and is rarely life-threatening.
But research and clinical experience suggest that many patients – and even some clinicians – may worry more about the possibility of uncontrolled bleeding when taking a blood thinner than on the benefit of stroke prevention. It’s important to put these risks in context.
Risk is the chance, or likelihood, that something will happen.
For example, people over 80 years old have a 10% risk of developing AFib. In other words, 10 out of 100 (or 1 in every 10) people in this age group will have AFib.
Using the CHA₂DS₂-VASc risk scoring (a tool used to predict the chances someone with AFib will have a stroke), if you are 75 years or older and have diabetes and high blood pressure, your score is 4. This means your risk of having a stroke in the next year is nearly 5%‐4.8% to be exact. In other words, among people who have these conditions, nearly 5 out of 100 will have a stroke.
A score of 6 ups the risk of stroke to 9.3% – meaning 9 out of 100 people will have a stroke this year.
The CHADS2-VASc score is the main way clinicians determine an individual’s stroke risk. There are other calculators that can be used to account for additional risk factors you may have. For example, kidney disease is not included in the CHADS2-VASc score. Revisit your personal risk of having a stroke each year. Ask about your risk and the best way to lower the chances of having a stroke.
“In general, most bleeding [related to anticoagulants] can be managed successfully and do not result in irreversible damage (with the exception of intracranial bleeding, which is very rare). In contrast, strokes are more likely to cause disability and can be life-altering, especially for young people,” said Mikhael F. El-Chami, MD, a heart specialist at Emory Healthcare.
While the likelihood of a major bleed from taking an anticoagulant is 2%-3% on average, the risk of stroke is higher. On average, the chance of having a stroke is 5% each year among people with AFib.
The trick is that two people with AFib may have very different risks of stroke and bleeding. That’s why reviewing your risks of both stroke and bleeding and making an informed decision with input from your care team is important.
The good news is there are many options nowadays for blood thinners. It’s important to talk with your care team about your risk of stroke and bleeding, and your risk for either or both may change over time.
Your health care team may use a number of tools to assess your risk of stroke to help decide whether a blood thinner is right for you.
For example, your health care team may use a formula called the CHA2DS2-VASc to calculate your risk of stroke.
This score is based on your age and history of several health issues. Each risk factor is assigned 1 or 2 points, for a maximum score of 9.
Risk Factor | Points |
Congestive Heart Failure | 1 |
High Blood Pressure | 1 |
A2: > 75 years old | 2 |
Diabetes (type 2) | 1 |
Stroke or Mini-Stroke | 2 |
Vascular Disease (heart attack, peripheral artery disease) | 1 |
Age: 65-74 years old | 1 |
Sc: Female Sex | 1 |
What your points mean:
0 = Low likelihood of stroke; no blood thinner is likely needed
1 = Low-moderate risk
2 or more = High risk
What does this all mean? Your CHA2DS2-VASc score can:
1) Inform treatment decisions about whether you need a blood thinner.
2) Predict your risk of stroke in the next year. For example, if your total score is 3, it means
you have a 3.2% chance of having a stroke in the next year. If your score is 6, the risk jumps up to a nearly 10% chance. Talk to your health care team to ask about your risk over time.
Also, there are tools to help you and your care team
estimate your bleeding risk. This information will help decide if you can safely take an anticoagulant, which one might be best, and how often you might need follow-up visits. Some people have a higher risk of bleeding due to other health problems
or medications they take. Ask your care team to review what increases your chance of bleeding.
This score is one tool that can help you and your care team get a sense for your likelihood of having a stroke. There are other calculators that can account for other conditions that can further increase your risk.