Do You Know Your CHA₂DS₂-VASc Score? Why It Matters for Stroke Prevention

Living with atrial fibrillation (AFib) means paying extra attention to your risk of stroke. AFib is an irregular heartbeat in which the heart's upper chambers quiver instead of beating effectively. When the heart doesn’t beat normally, blood can pool in the atria and form clots. If a clot travels to the brain, it can block blood flow and cause a stroke. This is why AFib is so closely linked to strokes – in fact, people with AFib are about five times more likely to have a stroke than people without AFib.

However, not everyone with AFib has the same stroke risk. It depends on your individual risk factors. Doctors have a tool to measure this risk: the CHA₂DS₂-VASc score. Knowing your CHA₂DS₂-VASc score is important for stroke prevention and overall heart health because it guides decisions about treatments (especially blood thinners) that can prevent strokes.

What Is the CHA₂DS₂-VASc Score?

The CHA₂DS₂-VASc score (pronounced “Chads-vasc”) is a clinical scoring system that helps predict stroke risk with AFib. Each letter in the name stands for a specific risk factor:

• C – Congestive heart failure
• H – Hypertension (high blood pressure)
• A₂ – Age 75 or older (this risk factor counts double)
• D – Diabetes (high blood sugar)
• S₂ – Stroke (prior stroke, TIA, or blood clot history – counts double)
• V – Vascular disease (like a previous heart attack or peripheral artery disease)
• A – Age 65 to 74
• Sc – Sex category (female gender)

This score is an expanded version of an older tool called the CHADS₂ score. The CHADS2 score included fewer factors, but experts found it missed some people who still had meaningful risk. Now, major heart guidelines recommend using CHA₂DS₂-VASc for all patients with atrial fibrillation to assess stroke risk. 

In practice, your doctor will calculate this score to decide if you need medication to prevent strokes. A high CHA₂DS₂-VASc score means a greater risk of stroke, while a low score means a lower risk.

Breaking Down the CHA₂DS₂-VASc Score: Your Risk Factors

How do you get your CHA₂DS₂-VASc score? It’s the sum of points for each risk factor you have. Let’s break down each component of “CHA₂DS₂-VASc” and what it means:

• C – Congestive Heart Failure (1 point): Add one point if you have congestive heart failure or reduced heart pumping function. Heart failure can cause blood to pool, contributing to clot formation.
• H – Hypertension (1 point): High blood pressure (hypertension) is a well-known stroke risk. If your blood pressure is persistently high or you’re on medication for high blood pressure, that’s one point.
• A₂ – Age 75 or Older (2 points): Age is among the most important risk factors. You score two points for age if you are 75 years or older. Getting older increases stroke risk significantly, so this factor is “weighted” double in the score.
• D – Diabetes (1 point): Diabetes means your blood sugar is too high. Having diabetes (Type 1 or Type 2) adds one point. Stroke risk is higher in people with diabetes, especially if it’s not well-controlled.
• S₂ – Prior Stroke or TIA (2 points): If you’ve had a stroke or a TIA (mini-stroke) in the past or any thromboembolism (a blood clot that traveled to an organ), that history gives 2 points. This is doubled because nothing predicts a future stroke like a prior stroke.
• V – Vascular Disease (1 point): This refers to other artery diseases. If you have a history of vascular disease – for example, a previous heart attack, peripheral artery disease (poor circulation in the legs), or significant plaque in the aorta – add one point. These conditions indicate plaque build-up and a tendency for clots that can elevate stroke risk.
• A – Age 65 to 74 (1 point): Being in the 65–74 age range gives you one point. (Note: you count either this age category or the 75+ category, not both. So if you’re over 75, you already counted 2 points for A₂, and you wouldn’t add this one.)
• Sc – Sex Category (Female) (1 point): Women with AFib have a slightly higher stroke risk than men. If you are female, add one point. (You get 0 points for this category if you're male.)

Now, add up all the points that apply to you. The lowest score is 0 (for a young male with none of the above risk factors). The highest possible score is 9 (for an older female with multiple risk factors). Most people with AFib will fall somewhere in between.

It’s worth noting that the CHA₂DS₂-VASc score applies to non-valvular AFib. If your AFib is caused by valvular heart disease or you have an artificial heart valve, you generally need anticoagulation regardless of these risk factors. Your doctor will manage that situation differently.

How Your CHA₂DS₂-VASc Score Guides Stroke Prevention Treatment

Your CHA₂DS₂-VASc score plays a key role in deciding whether you need anticoagulant therapy to reduce your stroke risk with AFib. Here’s how treatment decisions typically break down:

High Risk (Score ≥ 2 in men or ≥ 3 in women)

• You’re strongly advised to start anticoagulants—such as warfarin or DOACs (apixaban, rivaroxaban, dabigatran, or edoxaban). These medications can cut stroke risk by about 66% and are considered the gold standard for stroke prevention in patients with atrial fibrillation. If your score is high, the benefits of treatment far outweigh the risks.

Moderate/Borderline Risk (Score of 1 in men or 2 in women)

• This is a gray area. Your doctor will assess your risk factors, lifestyle, and medical history to determine the best action. Shared decision-making is key here. Some people may start blood thinners; others may hold off. The decision is made on a case-by-case basis.

Low Risk (Score of 0 in men or 1 in women)

• Anticoagulant therapy is usually not recommended. Your risk of stroke is low—around 1% per year—so the potential risks of blood thinners outweigh the benefits. Focus instead on managing heart health, blood pressure, and lifestyle factors.

In short, your CHA₂DS₂-VASc score helps identify who will benefit most from treatment. It’s a practical, evidence-based tool that allows your care team to match your AFib treatment options to your actual risk. Still, no two patients are exactly alike. If you have other health issues—like frequent falls or a high bleeding risk—your plan may differ.

Know Your Score, Know Your Options

Once you know your CHA₂DS₂-VASc score, the next step is acting on it. This might mean starting anticoagulant therapy, working with your doctor to build a personalized care plan, or simply keeping up with regular check-ups if your risk is low.

It's also important to stay on top of related health issues since each contributes to your overall stroke risk with AFib. And if standard treatment isn’t a fit, ask about alternative AFib treatment options or look into clinical trials for stroke prevention, especially if you're in a higher-risk category

Ready to Take the Next Step?

If your stroke risk with AFib is high, you may qualify for a clinical trial designed to explore new preventive treatments. Science 37 is currently recruiting participants for a study focused on stroke prevention in atrial fibrillation, especially those who can't tolerate traditional anticoagulants. Learn more or apply here Science 37’s Stroke Prevention Clinical Trial for AFib.