What is CHA₂DS₂-VASc?
CHA₂DS₂-VASc is a validated risk stratification scoring system used to assess stroke risk in patients with atrial fibrillation and guide decisions about anticoagulation therapy. 1
Components of the CHA₂DS₂-VASc Score
The CHA₂DS₂-VASc score consists of the following components, with points assigned for each risk factor:
- C: Congestive heart failure (1 point) - Signs and symptoms of right or left ventricular failure with objective evidence of cardiac dysfunction 1
- H: Hypertension (1 point) - Blood pressure >140/90 mmHg or current antihypertensive treatment 1
- A₂: Age ≥75 years (2 points) - Age is a major risk factor for stroke 1
- D: Diabetes mellitus (1 point) - Fasting glucose ≥126 mg/dL or treatment with hypoglycemic agents 1
- S₂: Prior Stroke, TIA, or thromboembolism (2 points) - History of these events significantly increases risk 1
- V: Vascular disease (1 point) - Prior myocardial infarction, peripheral artery disease, or aortic plaque 1
- A: Age 65-74 years (1 point) - Moderate increase in stroke risk 1
- Sc: Sex category - female (1 point) - Female sex is an independent risk factor 1
Clinical Application
- The CHA₂DS₂-VASc score ranges from 0 to 9 points, with higher scores indicating greater stroke risk 1
- For each 1-point increase in score, there is a corresponding increase in annual stroke risk 1
- A score of 0 corresponds to a truly low risk (0% annual stroke risk) 1
- A score of 1 corresponds to a low-moderate risk (1.3% annual stroke risk) 1
- A score of 2 corresponds to a moderate risk (2.2% annual stroke risk) 1, 2
- Scores ≥2 generally indicate the need for oral anticoagulation therapy 1, 2
Advantages Over Previous Scoring Systems
- The CHA₂DS₂-VASc score has largely replaced the older CHADS₂ score in clinical practice 1
- It provides better discrimination of truly low-risk patients than the CHADS₂ score 1, 3
- It has a broader score range (0-9) compared to CHADS₂ (0-6), allowing for more refined risk stratification 1
- It includes additional risk factors (vascular disease, age 65-74, female sex) not captured in CHADS₂ 1
- The C-statistic for CHA₂DS₂-VASc (0.606) is superior to that of CHADS₂ (0.561), indicating better predictive ability 1
Clinical Decision-Making
- For patients with a CHA₂DS₂-VASc score ≥2 (men) or ≥3 (women), oral anticoagulation is recommended 2
- For patients with a score of 0, anticoagulation is generally not recommended 1, 2
- For patients with a score of 1, anticoagulation decisions may be individualized based on bleeding risk and patient preferences 3
- The score helps identify patients who will benefit most from anticoagulation therapy to prevent stroke 1, 2
Limitations and Considerations
- While useful for risk stratification, the CHA₂DS₂-VASc score has only modest predictive accuracy (C-statistic around 0.6-0.7) 4
- The score does not account for bleeding risk, which should be assessed separately using tools like HAS-BLED 1, 2
- Some risk factors within the score may carry different weights in different populations 5
- The score has been validated primarily in patients with non-valvular atrial fibrillation 6, 7