CHA₂DS₂-VASc — stroke risk in atrial fibrillation
Estimates annual stroke/thromboembolism risk in non-valvular atrial fibrillation to guide anticoagulation decisions.
CHA₂DS₂-VASc score
0
Low risk — anticoagulation generally not indicated
- Adjusted annual stroke risk
- 0% /yearHistorical cohort estimate (Lip 2010) — individual risk varies
Caveats & limitations
- Not applicable to valvular AF (moderate–severe mitral stenosis or mechanical valve) — anticoagulate regardless of score.
- Risk percentages derive from historical European cohorts; absolute risk varies with contemporary management.
- Female sex alone (score 1 in a woman with no other factors) is not an indication for anticoagulation.
- Reassess risk periodically — age and comorbidities change the score.
Evidence & UK guidance
Primary evidence
Lip GYH, Nieuwlaat R, Pisters R, 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;137(2):263–272.
UK practice
NICE NG196 (2021): assess stroke risk with CHA₂DS₂-VASc; offer anticoagulation (DOAC first line, VKA if a DOAC is contraindicated or not tolerated) at score ≥2 and consider a DOAC for men with a score of 1. Do not anticoagulate men scoring 0 or women scoring 1 (sex alone). For bleeding risk NICE recommends ORBIT (other tools acceptable until embedded). Aspirin monotherapy must not be offered for stroke prevention in AF.
Official resources
Formula and citations last verified: 2026-08-03