Definitions and sources
CHA₂DS₂-VASc
CHF 1 · Hypertension 1 · Age ≥ 75 2 · Diabetes 1 · Stroke/TIA/TE 2 · Vascular disease 1 · Age 65–74 1 · Sex category (female) 1
Refinement of CHADS₂ from the Euro Heart Survey on Atrial Fibrillation (n = 1,084 without anticoagulation), adding vascular disease, age 65–74 and female sex and weighting age ≥ 75 at two points. A score of 0 identified patients at truly low risk.
Lip GYH, Nieuwlaat R, Pisters R, Lane DA, Crijns HJ. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: the Euro Heart Survey on Atrial Fibrillation. Chest 2010;137:263–272. DOI
HAS-BLED
Hypertension 1 · Abnormal renal 1 / liver 1 · Stroke 1 · Bleeding 1 · Labile INR 1 · Elderly 1 · Drugs 1 / alcohol 1
One-year major-bleeding risk in 3,978 Euro Heart Survey patients with AF; a score ≥ 3 marks high risk. Bleeding scores flag patients who need closer follow-up and correction of reversible factors, not exclusion from anticoagulation.
Pisters R, Lane DA, Nieuwlaat R, de Vos CB, Crijns HJ, Lip GY. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest 2010;138:1093–1100. DOI
Anticoagulation thresholds
Recommended: CHA₂DS₂-VASc ≥ 2 (men) or ≥ 3 (women); reasonable: 1 (men) or 2 (women)
Thresholds and risk-factor definitions follow the 2023 ACC/AHA/ACCP/HRS atrial fibrillation guideline, which recommends anticoagulation for an estimated annual thromboembolic risk ≥ 2 % and lists CHA₂DS₂-VASc as the validated tool for that estimate.
Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation. Circulation 2024;149:e1–e156. DOI
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