CHA2DS2-VASc Calculator for Atrial Fibrillation

Evaluates ischemic stroke risk in patients with atrial fibrillation

Criteria Poss. Point
Congestive heart failure
Signs/symptoms of heart failure confirmed with objective evidence of cardiac dysfunction
Resting BP > 140/90 mmHg on at least 2 occasions or current antihypertensive pharmacologic treatment
Age 75 years or older
Diabetes mellitus
Fasting glucose > 125 mg/dL or treatment with oral hypoglycemic agent and/or insulin
Stroke, TIA, or TE
Includes any history of cerebral ischemia
Vascular disease
Prior MI, peripheral arterial disease, or aortic plaque
Age 65 to 74 years
Sex category (female)
Female gender confers higher risk
Press 'Calculate' to view calculation results.

About This Calculator

Unlike the original CHADS2 score, which was based on a retrospective Medicare registry, CHA2DS2-VASc prospectively included patients from multiple countries who were aged 18 years and older.4 Patients were both ambulatory and hospitalized, and were followed for a total of 12 months.

CHADS2-VASc Score and Stroke Risk

Each increase in CHADS2-VASc was shown to predict ischemic stroke rate per year in a linear fashion:

Accuracy of CHADS2 vs. CHADS2-VASc

In a comparison study of multiple risk assessment tools for atrial fibrillation, CHA2DS2-VASc did not seem to outperform CHADS2. To classify the predictive ability of a scoring system, a C statistic is sometimes used. The C statistic is a number between 0.5 (no better than chance) and 1.0 (perfect prediction) indicating predictive ability. In this case, CHADS2 was 0.637 compared to CHADS2-VASc at 0.647.1. A "good" C statistic is usually at least 0.7 or better, indicating than neither system is particularly accurate in predicting stroke risk.

Classification of CHADS2 vs CHADS2-VASc

In both scoring systems, a score of 0 is "low" risk of stroke, 1 is "moderate", and any score above 1 is a "high" risk. The CHADS2-VASc system, with having three more potential variables, inevitably classifies more patients into a high-risk group. As shown in the diagram below, CHADS2-VASc classifies the same patient group into a higher risk category compared to CHADS2.1

Note how the CHADS2-VASc scoring system classifies more patients into the "high risk" category compared to CHADS2.

Gender and the Caveat to CHA2DS2-VASc

In general, a CHA2DS2-VASc score of 1 should warrant strong consideration for full oral anticoagulation.2 The one exception, however, is in patients who have a score of 1 due to gender alone. In these patients (female < 65 years old without other risk factors), antithrombotic therapy should not be given. This special situation may not be intuitive with the CHA2DS2-VASc scoring system.

References and Additional Reading

  1. Lip GY, Frison L, Halperin JL, Lane DA. Identifying patients at high risk for stroke despite anticoagulation: a comparison of contemporary stroke risk stratification schemes in an anticoagulated atrial fibrillation cohort. Stroke. 2010;41(12):2731-8. PMID 20966417.
  2. Camm AJ, Lip GY, De Caterina R, et al. 2012 focused update of the ESC Guidelines for the management of atrial fibrillation: an update of the 2010 ESC Guidelines for the management of atrial fibrillation. Eur Heart J. 2012;33(21):2719-47. PMID 22922413.
  3. Guyatt GH, Akl EA, Crowther M, et al. Executive summary: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(2 Suppl):7S-47S. PMID 22315257.
  4. Lip GY, Nieuwlaat R, Pisters R, et al. 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(2):263-72. PMID 19762550.


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Updated Nov 10, 2018
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