CHA₂DS₂-VASc refines CHADS₂ to estimate annual risk of ischaemic stroke and systemic embolism in adults with atrial fibrillation without moderate-to-severe mitral stenosis or mechanical heart valves.

The Euro Heart Survey derivation and validation study expanded earlier risk schemes by adding age 65 to 74 years, vascular disease and sex category.
Large registry cohorts such as the Swedish Atrial Fibrillation cohort show progressively higher untreated stroke risk as the score rises.
The 2023 ACC/AHA/ACCP/HRS atrial fibrillation guideline recommends anticoagulation based on estimated annual thromboembolic risk, with high-risk thresholds roughly aligning with CHA₂DS₂-VASc score 2 or more in men and 3 or more in women.
Female sex is best treated as a risk modifier. A score of 1 from sex alone usually remains low risk, while sex can amplify risk when age or comorbidities are present.

CHA₂DS₂-VASc score	Approximate untreated annual stroke or systemic embolism risk
0	Less than 0.5%
1	About 0.5 to 1%
2	About 2 to 3%
3	About 3 to 4%
4	About 4 to 6%
5	About 7 to 8%
6	About 9 to 10%
≥7	Above 10%, with wide confidence intervals

Absolute risk varies with population, follow-up duration and antithrombotic therapy. Use the score to support shared decision-making, not as a substitute for clinical judgement.

CHA₂DS₂-VASc Score for Atrial Fibrillation Stroke Risk