CHA₂DS₂-VASc score
Stroke risk in non-valvular atrial fibrillation, to guide oral anticoagulation.
When to use
- Patients with non-valvular atrial fibrillation or atrial flutter, to estimate ischaemic stroke risk and decide on oral anticoagulation.
- Not validated for valvular AF (moderate–severe mitral stenosis or a mechanical valve) — those patients require anticoagulation regardless.
Formula
Sum of: CHF (1) + Hypertension (1) + Age ≥75 (2) + Diabetes (1) + Stroke/TIA/thromboembolism (2) + Vascular disease (1) + Age 65–74 (1) + Sex category female (1). Maximum 9 points.
Pearls and pitfalls
- Female sex is a risk *modifier* rather than an independent risk factor: women with no other risk factors are at low risk.
- Bleeding risk (e.g. HAS-BLED) should be assessed alongside, but a high bleeding score is a prompt to correct modifiable risk factors — not to withhold anticoagulation.
References
- Lip GYH, et al. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach. Chest. 2010;137(2):263–72.
- Friberg L, Rosenqvist M, Lip GYH. Evaluation of risk stratification schemes for ischaemic stroke and bleeding in 182 678 patients with atrial fibrillation: the Swedish Atrial Fibrillation cohort study. Eur Heart J. 2012;33(12):1500–10.
- Hindricks G, et al. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation. Eur Heart J. 2021;42(5):373–498.
Interpretation of CHADS-VASc score and decisions on anticoagulation
| Men | Women | |||
|---|---|---|---|---|
| Points | Recommendation | Evidence | Recommendation | Evidence |
| --- | --- | --- | --- | --- |
| 0 | No treatment | Low | No treatment | High |
| 1 | Oral anticoagulation (warfarin or NOAK1 is considered for male patients with a score of 1 or more. Patient preference and risk-benefit balance determine whether treatment is initiated. | High | No treatment | High |
| 2 | Oral anticoagulation (warfarin or NOAC) is recommended for all male patients with scores of 2 or more. | Very high | Oral anticoagulation (warfarin or NOACs is considered for female patients with scores of 2 or more. Patient preference and the balance of risk and benefit determine whether treatment is initiated. | High |
| 3-9 | As above. | Very high | Oral anticoagulation (warfarin or NOAC) is recommended for all female patients with a score of 3 or more. | Very high |
1NOAC = novel oral anticoagulants (new oral anticoagulants) include apixaban (Eliquis®), dabigatran (Pradaxa®), edoxaban (Lixiana®), rivaroxaban (Xarelto®). If oral anticoagulation is indicated, NOACs should be chosen except in patients with moderate to severe mitral stenosis or mechanical heart valves; for these patients, warfarin is chosen instead (Class 1 B recommendation).
There are several models for risk-stratifying patients with atrial fibrillation, and CHADS-VASc is currently the most widely used model. The aim of CHADS-VASc is to identify patients at high risk of stroke, TIA or systemic thromboembolism and initiate treatment with anticoagulants (rarely with antiplatelet agents). CHADS-VASc predicts the risk of thromboembolism (stroke, TIA, systemic thromboembolism) in the next 12 months and the calculations apply to untreated patients with non-valvular atrial fibrillation (Table 1).
| CHADS-VASc Score | Risk of ischemic stroke | Risk för stroke/TIA/systemisk tromboembolism |
| 0 | 0.2% | 0.3% |
| 1 | 0.6% | 0.9% |
| 2 | 2.2% | 2.9% |
| 3 | 3.2% | 4.6% |
| 4 | 4.8% | 6.7% |
| 5 | 7.2% | 10.0% |
| 6 | 9.7% | 13.6% |
| 7 | 11.2% | 15.7% |
| 8 | 10.8% | 15.2% |
| 9 | 12.2% | 17.4% |
CHADS-Vasc score
- C: Congestive heart failure (1 point)
- H: Hypertension (1 point)
- A: Age 75 and older (2 points)
- D: Diabetes Mellitus (1 point)
- S: Prior Stroke or TIA or thromboembolism (2 points)
- V: Vascular disease (1 point)
- A: Age 65 to 74 years (1 point)
- Sc: Sex category: being female (1 point)
In clinical trials (see References), patients with non-valvular atrial fibrillation and a CHADS-VASc score of 0 have had a very low incidence of thromboembolic events, therefore withholding treatment should be considered. Among patients who are updated for anticoagulation, bleeding risk should be calculated using risk models such as ATRIA or HAS-BLED. There is at best weak support that acetylsalicylic acid (ASA) can be used as monotherapy (this means that acetylsalicylic acid should not, as a rule, be used for stroke prevention in patients with atrial fibrillation).