Stroke Risk Assessment (CHADS2, CHA2DS2-VASc)

The CHADS2 score is a validated stroke risk assessment tool for patients with AF that was first presented at the 2001 International Stroke Meeting. It is used to determine whether or not treatment is required with anticoagulation therapy or antiplatelet therapy. A high CHADS2 score corresponds to a greater risk of stroke, while a low CHADS2 score corresponds to a lower risk of stroke. Adding together the points that correspond to the conditions that a patient has will result in the CHADS2 score that is used to estimate stroke risk. The possible score is 0-6:

C Congestive Heart failure 1
H Hypertension 1
A Age >75 years 1
D Diabetes 1
S2 Stroke or TIA 2

Based on the score, the approximate annual stroke risks are:

0 3% Low
1 4% Low
2 5% Intermediate
3 6% Intermediate
4 8% High
5 12% High
6 18% High


Score Therapy
1 ASA or oral anticoagulant
≥ 2 oral anticoagulant

It was felt by some that CHADS2scoring system failed to include some risk factors. If the CHADS2 score is 0-1, other stroke risk modifiers could be considered to determine whether or not to use oral anticoagulants.

C CHF/LV dysfunction 1
H Hypertension 1
A2 Age ≥ 75 2
D Diabetes mellitus 1
S2 Stroke/TIA/TE
V Vascular disease - CAD, MI, PAD or aortic plaque 1
A Age 65-74 1
Sc Sex category - Female 1

Recommendations for anticoagulation based on CHADS2 and CHA2DS2-VASc are the same: oral anticoagulation is recommended for a score of  ≥ 2.

Stroke risk assessment should always include an assessment of bleeding risk. This can be done using validated bleeding risk scores, such as a HEMORR2HAGES or HAS-BLED scores.


Gage BF, Waterman AD, Shannon W, Boechler M, Rich MW, Radford MJ. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA. 2001 Jun 13;285(22):2864-70.

Lip GY, 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 Feb;137(2):263-72. Epub 2009 Sep 17.