What is the CHA₂DS₂-VASc score?
CHA₂DS₂-VASc is a point score that estimates the risk of stroke and systemic thromboembolism in atrial fibrillation (AF). It applies to people without a mechanical heart valve or moderate to severe mitral stenosis. Lip and colleagues published it in 2010 from the Euro Heart Survey, and it became the standard way to grade stroke risk in AF.
In 2024 the European Society of Cardiology simplified it to CHA₂DS₂-VA by dropping the point for female sex. This calculator shows both numbers, so it works whether your protocol still uses the original score or has moved on. For the full story of the change, read CHA₂DS₂-VASc vs CHA₂DS₂-VA.
CHA₂DS₂-VASc criteria and points
| Letter | Criterion | Points |
|---|---|---|
| C | Congestive heart failure | 1 |
| H | Hypertension | 1 |
| A₂ | Age 75 or over | 2 |
| D | Diabetes | 1 |
| S₂ | Prior stroke, TIA or thromboembolism | 2 |
| V | Vascular disease (MI, PAD, aortic plaque) | 1 |
| A | Age 65–74 | 1 |
| Sc | Sex category: female | 1 |
The two age items exclude each other, so the calculator asks for Age once: “Under 65” (0), “65–74 (+1)” or “75 or over (+2)”. CHA₂DS₂-VA is the same table without the last row.
How do you calculate CHA₂DS₂-VASc?
- Answer each item. Everything starts at “No”, Age at “Under 65” and Sex at “Male”.
- Set Sex to “Female (+1)” where it applies. It changes CHA₂DS₂-VASc but not CHA₂DS₂-VA.
- Read the CHA₂DS₂-VASc score, the CHA₂DS₂-VA line and the Interpretation.
- Check the working underneath. It lists every item that scored and the sum.
Interpretation
The calculator bands risk on CHA₂DS₂-VA, in line with the 2024 ESC guidelines:
| CHA₂DS₂-VA | Interpretation shown |
|---|---|
| 0 | Low (CHA₂DS₂-VA 0) |
| 1 | Intermediate (CHA₂DS₂-VA 1) |
| 2 or more | High (CHA₂DS₂-VA ≥ 2) |
In broad terms, the 2024 ESC guidelines (Van Gelder et al.) recommend oral anticoagulation when CHA₂DS₂-VA is 2 or more, and say it should be considered when it is 1. Both always go with an individual look at benefit and bleeding risk. The score supports that discussion; the prescriber makes the decision.
Worked examples
Example 1 – several risk factors. A 72-year-old woman with hypertension and type 2 diabetes. Hypertension +1, age 65–74 +1, diabetes +1, female +1: 1 + 1 + 1 + 1 = CHA₂DS₂-VASc 4. Without the sex point, CHA₂DS₂-VA 3: High (CHA₂DS₂-VA ≥ 2).
Example 2 – female sex only. A 58-year-old woman with no other risk factors. Female +1 = CHA₂DS₂-VASc 1, but CHA₂DS₂-VA 0: Low (CHA₂DS₂-VA 0).
Example 3 – age only. A 67-year-old man with no other risk factors. Age 65–74 +1 = CHA₂DS₂-VASc 1 and CHA₂DS₂-VA 1: Intermediate (CHA₂DS₂-VA 1).
Examples 2 and 3 show why the band uses CHA₂DS₂-VA: the same CHA₂DS₂-VASc of 1 means different things depending on where the point comes from.
Limitations
- Population-level estimate. The score groups people by risk. It cannot say whether one person will have a stroke.
- Not for valvular AF in the strict sense. Mechanical valves and moderate to severe mitral stenosis are outside its scope.
- Other risk factors are not counted. Kidney function, left atrial size, AF burden and biomarkers can all affect risk but are not part of the score.
- Stroke risk is only half the picture. Assess bleeding risk separately, for example with the HAS-BLED calculator, and look at modifiable bleeding factors in their own right. Kidney function also guides the choice and dose of anticoagulant: see the creatinine clearance calculator.
Common mistakes
- Scoring age twice. A 78-year-old gets 2 points for age, not 2 + 1.
- Counting a stroke as 1 point. Prior stroke, TIA or systemic embolism is worth 2.
- Forgetting vascular disease. Previous myocardial infarction, peripheral arterial disease and aortic plaque all count.
- Reading CHA₂DS₂-VASc 1 in a woman as intermediate risk. It’s worth checking CHA₂DS₂-VA: if the only point is sex, it is 0.
- Scoring once and never again. People move up a band as they age or gain diagnoses.
Frequently asked questions
What is the difference between CHA₂DS₂-VASc and CHA₂DS₂-VA?
CHA₂DS₂-VA is CHA₂DS₂-VASc without the point for female sex. The 2024 ESC atrial fibrillation guidelines adopted it because female sex behaves as an age-dependent risk modifier rather than an independent risk factor. All the other items and their points are the same.
Which score does the risk band use?
The band is based on CHA₂DS₂-VA: 0 is low, 1 is intermediate and 2 or more is high. The full CHA₂DS₂-VASc is still shown as the main number because many protocols and documents use it. So a woman’s band can sit one step lower than her CHA₂DS₂-VASc alone suggests.
What is the maximum CHA₂DS₂-VASc score?
CHA₂DS₂-VASc goes up to 9, and CHA₂DS₂-VA up to 8 because the sex point is left out. The top of the scale is reached by a woman aged 75 or over with every other risk factor: heart failure, hypertension, diabetes, prior stroke or TIA, and vascular disease.
Does a woman with no other risk factors count as high risk?
No. She scores 1 on CHA₂DS₂-VASc but 0 on CHA₂DS₂-VA, which the calculator labels as Low (CHA₂DS₂-VA 0). Even under the older scheme, a score of 1 made up only of the sex point was treated as low risk. Her risk rises only when she gains another factor, such as age 65 or hypertension.
Is the score used for atrial flutter too?
Generally yes. Guidelines apply the same stroke-risk assessment to atrial flutter as to atrial fibrillation, because the two often occur in the same patient. We recommend checking how your local protocol handles flutter, and scoring it with the same items and points.
Does the score apply to people with a mechanical heart valve?
No. People with mechanical heart valves or moderate to severe mitral stenosis were not part of the populations behind the score. Their risk of clots is high whatever the score says, and guidelines manage their anticoagulation separately, usually with a vitamin K antagonist such as warfarin.
Should the score be recalculated over time?
Yes. Age and new diagnoses such as hypertension, diabetes or heart failure change the score. Guidelines advise reassessing stroke risk at regular intervals rather than scoring once. A patient at 0 or 1 today may need a different discussion after turning 65 or after a new diagnosis.
Sources
- Lip GY et al. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: the Euro Heart Survey on atrial fibrillation. Chest 2010
- Van Gelder IC et al. 2024 ESC Guidelines for the management of atrial fibrillation. Eur Heart J 2024