The CHA₂DS₂-VASc score is a tool used to estimate the risk of stroke in individuals with atrial fibrillation. It assigns points based on various risk factors, and the total score guides clinical decisions regarding anticoagulation therapy.

Here’s how the scoring works:

- Age:
  - Below 65 years scores 0 points.
  - Between 65 and 74 years scores 1 point.
  - 75 years or older scores 2 points.

- Sex:
  - Female scores 1 point.
  - Male scores 0 points.

- Hypertension:
  - If present, scores 1 point.
  - If absent, scores 0 points.

- Diabetes Mellitus:
  - If present, scores 1 point.
  - If absent, scores 0 points.

- Congestive Heart Failure/Left Ventricular Dysfunction:
  - If present, scores 1 point.
  - If absent, scores 0 points.

- History of Stroke/Thromboembolism/Transient Ischemic Attack:
  - If present, scores 2 points.
  - If absent, scores 0 points.

- History of Vascular Disease (such as prior myocardial infarction or peripheral artery disease):
  - If present, scores 1 point.
  - If absent, scores 0 points.

To calculate the score, assess each of these factors for the individual and sum the respective points.

Once the total score is determined, it is interpreted as follows:
- A score of 0 implies a 0.2% risk of ischemic stroke and a 0.3% risk of stroke/transient ischemic attack/systemic embolism.
- A score of 1 indicates a 0.6% risk of ischemic stroke and a 0.9% risk of stroke/TIA/systemic embolism.
- A score of 2 suggests a 2.2% risk of ischemic stroke and a 2.9% risk of stroke/TIA/systemic embolism.
- A score of 3 means a 3.2% risk of ischemic stroke and a 4.6% risk of stroke/TIA/systemic embolism.
- A score of 4 reveals a 4.8% risk of ischemic stroke and a 6.7% risk of stroke/TIA/systemic embolism.
- A score of 5 corresponds to a 7.2% risk of ischemic stroke and a 10.0% risk of stroke/TIA/systemic embolism.
- A score of 6 represents a 9.7% risk of ischemic stroke and a 13.6% risk of stroke/TIA/systemic embolism.
- A score of 7 reflects an 11.2% risk of ischemic stroke and a 15.7% risk of stroke/TIA/systemic embolism.
- A score of 8 implies a 10.8% risk of ischemic stroke and a 15.2% risk of stroke/TIA/systemic embolism.
- A score of 9 equates to a 12.2% risk of ischemic stroke and a 17.4% risk of stroke/TIA/systemic embolism.

This comprehensive scoring system helps identify the stroke risk and aids healthcare providers in making informed decisions about patient care.

The CHA₂DS₂-VASc score is a clinical prediction rule for estimating the risk of stroke in patients with non-rheumatic atrial fibrillation (AF). The acronym stands for Congestive heart failure, Hypertension, Age ≥75 years (doubled), Diabetes mellitus, Stroke (doubled), Vascular disease, Age 65–74 years, and Sex category (female). Each factor is assigned a certain number of points, and the total score is used to estimate the risk of stroke. 

This calculator is specifically applicable to patients with non-rheumatic atrial fibrillation, including those who are being considered for anticoagulation therapy. The clinical utility of the CHA₂DS₂-VASc score is to guide clinicians in making decisions about anticoagulation therapy, as higher scores indicate a greater risk of stroke and may warrant more aggressive treatment.

The CHA₂DS₂-VASc score should not be used in patients with rheumatic atrial fibrillation, as the risk factors and stroke risk in these patients are different. It is also not applicable to patients with transient causes of atrial fibrillation, such as those due to a reversible cause like surgery or acute illness.

CHA₂DS₂-VASc score for stroke risk in atrial fibrillation

The CHA2DS2-VASc Score A Predictor of Thromboembolic Events and Mortality In Patients With an Implantable Monitoring Device Without Atrial Fibrillation.