CHA₂DS₂-VASc Score (Stroke Risk in Atrial Fibrillation)
Compute CHA₂DS₂-VASc to estimate annual ischaemic stroke risk in non-valvular atrial fibrillation, used to guide anticoagulation decisions.
Anticoagulation generally not indicated for stroke prevention
Refs: Lip GY et al. Chest 2010;137(2):263–272. 2023 ACC/AHA/ACCP/HRS AF guideline. 2024 ESC AF guideline (Van Gelder IC et al., Eur Heart J 2024). Thresholds: ≥2 in men, ≥3 in women favour OAC. Combine with HAS-BLED bleeding score and shared decision-making. Non-valvular AF only — mechanical valves and moderate–severe mitral stenosis need anticoagulation regardless. Clinical decision support tool; not a substitute for clinical judgment.
General calculation reads
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About this tool
CHA₂DS₂-VASc (Lip et al., Chest 2010) is the score used in modern atrial-fibrillation guidelines to estimate annual ischaemic stroke risk and decide whether to start anticoagulation. It refines the older CHADS₂ by giving extra weight to two risk factors (Age ≥75 and prior Stroke/TIA, hence the subscript 2) and adding three new ones (Vascular disease, Age 65–74, female Sex category). Scoring: Congestive heart failure +1, Hypertension +1, Age ≥75 +2, Diabetes mellitus +1, Stroke/TIA/thromboembolism +2, Vascular disease (prior MI, PAD, aortic plaque) +1, Age 65–74 +1, female Sex category +1 (when ≥1 other risk factor present). 2024 ESC and 2023 ACC/AHA/HRS guidelines recommend oral anticoagulation for scores ≥2 in men and ≥3 in women, with shared decision-making at score 1 (men) / 2 (women). Reference: Lip GY et al., Chest 2010;137(2):263–272; 2024 ESC AF guidelines (Van Gelder IC et al., Eur Heart J 2024). Clinical decision support tool — confirm against full assessment and bleeding-risk score (HAS-BLED); not a substitute for clinical judgment.
How to use it
- Tick each risk factor that applies.
- Read the total score and the annual stroke-risk estimate from the validation cohort.
- Use the score alongside HAS-BLED and shared decision-making to choose anticoagulation.
Frequently asked questions
- What does each letter stand for?
- C: Congestive heart failure (+1). H: Hypertension (+1). A₂: Age ≥75 (+2). D: Diabetes (+1). S₂: Stroke/TIA/TE history (+2). V: Vascular disease — MI, PAD, complex aortic plaque (+1). A: Age 65–74 (+1). Sc: female Sex category (+1).
- Why the subscript 2 on age and stroke?
- Those two factors carry roughly double the per-year stroke risk of the +1 factors in the derivation cohort, so they get +2. The subscript is a reminder to score them correctly.
- When does the "female sex" point count?
- In modern guidelines (2023 ACC/AHA, 2024 ESC), female sex is a risk modifier rather than an independent risk factor: women score +1 only when ≥1 other risk factor is present, and the anticoagulation threshold is ≥3 in women vs ≥2 in men.
- What about valvular AF?
- CHA₂DS₂-VASc is for non-valvular AF. In mechanical valves or moderate–severe mitral stenosis, anticoagulation with warfarin is recommended regardless of score.
- How does this relate to HAS-BLED?
- CHA₂DS₂-VASc estimates stroke risk; HAS-BLED estimates bleeding risk. They are used together — a high stroke risk usually still favours anticoagulation even if HAS-BLED is also elevated, but HAS-BLED flags modifiable bleeding risk factors to address.
- Is data sent anywhere?
- No. The calculation runs in your browser.