Thrombosis & Bleeding

Stroke Risk in Atrial Fibrillation (CHA₂DS₂-VASc) Calculator

Estimates stroke and thromboembolism risk in atrial fibrillation to guide anticoagulation, with the sex-specific thresholds.

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

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Formula

C Congestive heart failure or LV dysfunction +1
H Hypertension +1
A₂ Age ≥75 years +2
D Diabetes mellitus +1
S₂ Prior stroke, TIA or thromboembolism +2
V Vascular disease (prior MI, peripheral artery disease, aortic plaque) +1
A Age 65–74 years +1
Sc Sex category: female +1
Maximum 9. CHA₂DS₂-VA (ESC 2024) is the same score without the sex point (maximum 8).

How it is used

• Anticoagulation is recommended when the annual thromboembolic risk is ≥2% (score ≥2 in men, ≥3 in women) and is reasonable at 1% to under 2% (score 1 in men, 2 in women) (ACC/AHA/ACCP/HRS 2023).
• Female sex modifies risk rather than adding it on its own, which is why the thresholds for women are one point higher (ACC/AHA 2023).
• ESC 2024 uses CHA₂DS₂-VA, the same items without the sex point (with some definitions updated): anticoagulation is recommended at 2 or more and should be considered at 1 (ESC 2024).
• Not for AF with a mechanical heart valve or moderate-to-severe mitral stenosis: those patients take warfarin whatever the score (ACC/AHA 2023).

Key points

• Aspirin is not a substitute for anticoagulation to prevent stroke in AF (ESC 2024).

Same formula as the app. Open it in the web app.

Related one-pagers

• Rhythm GalleryAFFIRM (2002, 4,060 patients) found no survival gain from rhythm control (5-year mortality 23.8% vs 21.3%, P = 0.08); most strokes occurred off warfarin or below target INR. RACE II (2010) found lenient control (resting rate under 110) as good as strict (under 80), 12.9% vs 14.9% events at 3 years, and the 2023 guideline accepts a resting target under 100 to 110. EAST-AFNET 4 (2020, 2,789 patients) turned practice toward early rhythm control: started within a year of diagnosis, it reduced cardiovascular death, stroke and HF or ACS admissions (3.9 vs 5.0 per 100 person-years). Anticoagulate at an annual stroke risk of 2% or more, about CHA₂DS₂-VASc 2 or more in men and 3 or more in women (2023, Class 1); a DOAC is preferred except with a mechanical valve or moderate to severe mitral stenosis.
• After Cardiac SurgeryPOAF follows 30% to 50% of cardiac operations (ESC 2024; ERAS/STS 2024 quotes 15% to 40%), more after valve and combined surgery, and most often starts on days 2 to 4. Triggers include pericardial blood and inflammation, atrial stretch, catecholamines, electrolyte shifts and beta-blocker withdrawal. It raises stroke risk, lengthens the stay and carries a 4- to 5-fold higher risk of recurrent AF over 5 years (ESC 2024).
• Pulmonary Embolism
• Bleeding, Reversal, HIT and DIC

Related calculators

• Bleeding Risk on Anticoagulation (HAS-BLED)
• Caprini VTE Risk Score for Surgery (Caprini)
• Heparin-Induced Thrombocytopenia Probability (4Ts)
• Padua Prediction Score for VTE (Padua)
• Pulmonary Embolism Severity Index (PESI)
• Simplified PESI (sPESI)
• Wells Score for PE (Wells)

For education and exam preparation only. Follow your institution’s protocols. For education and exam preparation only. Verify results independently and follow your institution’s protocols. Not a substitute for clinical judgment.