CHA₂DS₂-VASc score

The CHA₂DS₂-VASc score is a clinical risk stratification tool used to estimate the risk of stroke and systemic embolism in patients with atrial fibrillation (AF). It is widely used to guide decisions about oral anticoagulation.

The score refines earlier risk models by including additional vascular and demographic risk factors and is recommended in UK and international guidelines.

Clinical context and use

CHA₂DS₂-VASc is used in patients with non-valvular atrial fibrillation, including paroxysmal, persistent, and permanent AF.

Its primary purpose is to identify patients who are likely to benefit from anticoagulation in order to reduce the risk of ischaemic stroke. It is typically used alongside bleeding risk assessment and shared decision-making.

The score should be recalculated periodically, as stroke risk increases with age and the development of new comorbidities.

Points are assigned for the following risk factors:

• Congestive heart failure or left ventricular dysfunction: 1 point.

• Hypertension, treated or untreated: 1 point.

• Age 75 years or older: 2 points.

• Diabetes mellitus: 1 point.

• Prior stroke, transient ischaemic attack, or systemic embolism: 2 points.

• Vascular disease, including previous myocardial infarction, peripheral arterial disease, or aortic plaque: 1 point.

• Age 65–74 years: 1 point.

• Sex category female: 1 point.

The total score ranges from 0 to 9.

Higher scores indicate a greater annual risk of stroke.

In UK practice, anticoagulation is generally recommended for:

• Men with a score of 2 or more.

• Women with a score of 3 or more.

Anticoagulation may be considered for:

• Men with a score of 1.

• Women with a score of 2.

A score of 0 in men, or 1 in women where the only point is sex category, is generally considered low risk and does not usually require anticoagulation.

Decisions should always be individualised and made in the context of patient preference, bleeding risk, and overall clinical picture.

The CHA₂DS₂-VASc score helps identify patients who are likely to derive net benefit from anticoagulation therapy.

It does not determine the choice of anticoagulant. Selection between direct oral anticoagulants and vitamin K antagonists depends on patient characteristics, contraindications, renal function, drug interactions, and local guidance.

Stroke prevention strategies should be reviewed regularly, particularly after hospital admissions or changes in health status.

CHA₂DS₂-VASc has been validated in large cohort studies and has demonstrated improved discrimination of stroke risk compared with earlier scoring systems.

It is incorporated into NICE, ESC, and other international guidelines for the management of atrial fibrillation.

The score estimates population-level risk and does not predict individual outcomes with certainty.

It does not account for bleeding risk, frailty, or life expectancy, which must also be considered. Bleeding risk assessment tools, such as HAS-BLED, are commonly used alongside CHA₂DS₂-VASc to support balanced decision-making.

The score should not be used in patients with mechanical heart valves or moderate to severe mitral stenosis, where anticoagulation decisions follow different guidance.

Using a recognised scoring system can support consistent prescribing, documentation, and audit. Recording the score also helps structure discussions with patients about stroke risk and the potential benefits and risks of anticoagulation.