CHA₂DS₂-VASc Stroke Risk Calculator

What Is CHA₂DS₂-VASc? The CHA₂DS₂-VASc score is a clinical scoring system used to estimate the risk of stroke in patients with non-valvular atrial fibrillation (AFib). AFib is the most common heart rhythm disorder, affecting over 33 million people worldwide. Without treatment, AFib increases stroke risk by 5-fold compared to the general population. The score was developed in 2010 by Lip and colleagues and is now the international standard, used in ESC, ACC/AHA, and most national guidelines.

Score Components C, Congestive heart failure (1 point): recent decompensated heart failure or reduced ejection fraction. H, Hypertension (1 point): persistent BP above 140/90 mmHg or on antihypertensive medication. A₂, Age ≥ 75 years (2 points): higher weighting due to exponentially higher stroke risk. D, Diabetes mellitus (1 point): type 1 or type 2 diabetes on medication. S₂, Prior Stroke / TIA / Thromboembolism (2 points): the strongest independent risk factor. V, Vascular disease (1 point): prior MI, peripheral artery disease, or aortic plaque. A, Age 65–74 years (1 point): the two age criteria are alternatives, never both. A patient of 78 scores 2 for A₂ and nothing for A, which is why the calculator asks for one age band rather than two yes-or-no questions. Sc, Sex category female (1 point): biological females have higher baseline stroke risk in AFib.

Annual Stroke Risk by Score Score 0 (male) or 1 (female alone): low risk, approximately 0% per year. No anticoagulation needed. Score 1 (male): approximately 1.3% per year. Guidelines suggest anticoagulation consideration. Score 2: approximately 2.2% per year. Oral anticoagulation is recommended. Score 3: approximately 3.2% per year. Strong recommendation for anticoagulation. Score 4: approximately 4.0% per year. High risk, anticoagulation essential. Score 5: approximately 6.7% per year. Score 6: approximately 9.8% per year. Score 7+: very high risk, 9–15%+ per year. Aggressive anticoagulation management required.

Treatment Guidelines Thresholds are read on the score excluding the sex point, because being female is not on its own an indication for anticoagulation. A woman with a score of 1 from sex alone is treated as a 0. Score 0 after that exclusion: no anticoagulation. Score 1: consider anticoagulation. This is the band where the decision genuinely turns on bleeding risk and patient preference rather than on the number. Score 2 or more: oral anticoagulation recommended, with a DOAC (apixaban, rivaroxaban, dabigatran, edoxaban) preferred in non-valvular AFib. Warfarin remains an option but requires more monitoring (INR target 2.0–3.0). Stroke risk is only half the decision. Bleeding risk, usually scored with HAS-BLED, is the other half, and a high bleeding score is a reason to correct modifiable risk factors rather than to withhold treatment.

A caveat on the risk percentages The annual figures above come from the Lip 2010 Euro Heart Survey cohort, and they are reported here as published. They do not climb cleanly at the top of the scale: score 7 came out slightly below score 6, because very few patients in that cohort scored so high. Read anything at 7 or above as very high risk rather than reading the exact percentage.

Important Disclaimer This calculator provides a general estimate for educational purposes only. It is NOT a substitute for clinical evaluation by a licensed healthcare professional.