CHA2DS2-VASc Score Calculator

CHA2DS2-VASc stratifies stroke risk specifically in non-valvular atrial fibrillation, where the fibrillating atria allow blood to stagnate and clot, most often in the left atrial appendage. The eight components split into single- and double-weighted risk factors: congestive heart failure, hypertension, diabetes, vascular disease (prior MI, peripheral artery disease, aortic plaque), age 65-74, and female sex each contribute 1 point, while age 75 or older and any prior stroke, TIA, or thromboembolism each contribute 2 points, reflecting their outsized independent risk contribution in the derivation cohort. Female sex is only counted as a risk modifier when at least one other risk factor is present — a woman with a score based on sex alone is not treated as truly higher risk. Guidelines translate the score directly into an anticoagulation recommendation: a score of 0 in men (or 1 in women, from sex alone) needs no antithrombotic therapy, a score of 1 in men is a shared decision, and a score of 2 or higher in men (3 or higher in women) is a guideline-level indication for oral anticoagulation with a DOAC or warfarin. The score deliberately does not attempt to weigh bleeding risk — that is the separate role of HAS-BLED — so the two tools are meant to be used together rather than as alternatives to one another.

The original CHADS2 score was published by Brian Gage and colleagues in JAMA in 2001, built from Medicare claims data on beneficiaries with atrial fibrillation, and used five simple criteria (CHF, hypertension, age ≥75, diabetes, prior stroke doubled) to guide anticoagulation. It became the standard AF risk tool for nearly a decade but was criticized for classifying a very large share of patients as 'low risk' who nonetheless went on to have strokes, since it omitted vascular disease, sex, and the 65-74 age band entirely. Gregory Lip and colleagues addressed this gap in a 2010 Chest paper, expanding CHADS2 into the nine-point CHA2DS2-VASc score by adding vascular disease, an intermediate age category, and female sex as risk modifiers, validated against a Euro Heart Survey cohort of over 1,000 AF patients. The refined score demonstrated markedly better discrimination for the truly low-risk group and was adopted into the 2012 European Society of Cardiology AF guidelines, subsequently becoming the standard recommended tool in both European and American (ACC/AHA/HRS) atrial fibrillation guidelines through the 2020s.