What the CHA₂DS₂-VASc score does
The CHA₂DS₂-VASc score estimates the yearly risk of stroke and systemic embolism in people with non-valvular atrial fibrillation (AF). It refines the earlier CHADS₂ score by adding vascular disease, a wider age band, and sex, improving the identification of genuinely low-risk patients who may not need anticoagulation. The score is central to the decision of whether to start an oral anticoagulant.
How it works
The acronym maps to points:
- C — Congestive heart failure / LV dysfunction: +1
- H — Hypertension: +1
- A₂ — Age ≥75: +2
- D — Diabetes mellitus: +1
- S₂ — Prior Stroke, TIA, or thromboembolism: +2
- V — Vascular disease (prior MI, peripheral artery disease, aortic plaque): +1
- A — Age 65–74: +1
- Sc — Sex category female: +1
The points are summed to a maximum of 9. Higher scores correspond to higher annual stroke risk, rising steeply above a score of 3. Guidelines recommend anticoagulation at 2 or more in men and 3 or more in women, with a shared-decision discussion at 1 (men) or 2 (women).
Score and treatment decision table
| Score | Interpretation | Anticoagulation guidance |
|---|---|---|
| 0 (men) / 1 women-only (women) | Low risk | No anticoagulation indicated |
| 1 (men) / 2 (women, 1 non-sex risk factor) | Low-moderate risk | Consider anticoagulation; shared decision |
| 2+ (men) / 3+ (women) | Moderate to high risk | Anticoagulation recommended unless contraindicated |
Note that female sex as the only risk factor (score of 1 for a woman with no other comorbidities) is treated as low risk — it is a modifier that increases risk in combination with other factors, not an independent risk factor on its own.
Worked example
A 78-year-old woman presents with a new diagnosis of AF. She has a history of hypertension and was diagnosed with type 2 diabetes five years ago. There is no prior stroke, TIA, heart failure, or vascular disease.
- Age ≥75: +2
- Female sex: +1
- Hypertension: +1
- Diabetes: +1
- Total: 5
A score of 5 falls firmly in the high-risk category for a woman, and oral anticoagulation is clearly recommended. The clinician would then assess bleeding risk (for example using HAS-BLED) and discuss anticoagulant options — typically a DOAC rather than warfarin per current guidelines.
Clinical notes
This tool is for educational reference. The score should be interpreted in the full clinical context by a qualified clinician. Always pair the stroke estimate with a bleeding-risk assessment such as HAS-BLED, and document shared decision-making about anticoagulation choices and the patient’s preferences regarding stroke versus bleeding risk.