CHA₂DS₂-VASc Score

The CHA₂DS₂-VASc Score is the most commonly utilized method to predict thromboembolic risk in atrial fibrillation.

CHA₂DS₂ stands for (Congestive heart failure, Hypertension, Age ( > 65 = 1 point, > 75 = 2 points), Diabetes, previous Stroke/transient ischemic attack (2 points). VASc stands for vascular disease (peripheral arterial disease, previous myocardial infarction, aortic atheroma), and sex category (female gender) is also included in this scoring system.

As outlined above, each risk factor receives 1 point except age > 75 and stroke/TIA, which receive 2 points. Patients with 2 or more points should receive full anticoagulation with warfarin, dabigatran, rivaroxaban or apixaban. Patients with 1 point can be treated with either aspirin alone or full anticoagulation based on the specific individual.

A patient’s annual risk stroke generally increases along with points on the CHA₂DS₂-VASc Score; points and risk equivalents are outlined in the calculator below.

Annual Stroke Risk, according to the CHA₂DS₂-VASc Score

• 1 point   = 1.3%
• 2 points = 2.2%
• 3 points = 3.2%
• 4 points = 4.0 %
• 5 points = 6.7 %
• 6 points = 9.8%
• 7 points = 9.6% (study had small sample size with this score, leading to more variability)
• 8 points = 6.7% (study had very small sample size)
• 9 points = 15.2%

This is excellent information for clinicians to use in educating patients about annual stroke risk. Many patients are hesitant to begin anticoagulation due to the expense and inconvenience. However, after understanding that a 4% annual risk for stroke (if the CHA₂DS₂-VASc Score is 4) equates to 40% risk over 10 years, patients are more willing to comply.

As a general rule, regardless of the above scoring system, if a patient’s atrial fibrillation is caused by valvular heart disease ― that is, severe mitral regurgitation or mitral stenosis ― then anticoagulation should be utilized.

References:
1. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine
2. Gage BF, et al. Selecting Patients With Atrial Fibrillation for Anticoagulation Stroke Risk Stratification in Patients Taking Aspirin. Circulation. 2004;doi:10.1161/01.CIR.0000145172.55640.93
3. Hurst’s the Heart, 13th Edition