This CHA2DS2 VASc score for atrial fibrillation stroke risk calculator determines risk of stroke and other thromboembolic events in patients with heart disease. You can read more about this adaptation of the original CHADS2 model and its interpretation below the tool.

Patient age

Patient gender

Congestive heart failure history

Hypertension history

Diabetes mellitus history

Stroke or TIA symptoms previously

Vascular disease history

How does this CHA2DS2 VASc score for atrial fibrillation stroke risk calculator work?

This is a health tool that is used to estimate the thromboembolic status of patients suffering from non valvular atrial fibrillation who are not under any anticoagulation treatment at the moment of the assessment. It is based on the CHA2DS2-VASc score which is an improved version of the previous CHADS2 score.

Beside the variables used in the original version, this one brings additional vascular stroke factors in consideration and is said to be a better tool for stratifying risk, even in patients that have scored 0 in the original version.  There are three age groups to be selected from, as well as the gender and for the rest of the factors, each is to be answered to by yes or no. Every answer is awarded a number of points that are summed at the end of the assessment to provide the final score.

■ Patient age – There is the below 65 age group, the between 65 and 74 age group and the above 75 group. The risk of stroke is considered to be proportional to the age increase and so in these cases, age is considered an important risk factor.

■ Patient gender – This is one of the new variables introduced and takes account of gender while classifying the females by a higher score, meaning a higher risk of stroke.

■ Congestive heart failure history – This is one of the main risk factors as congestive heart disease which impairs the hearts pump function can be a cause of ischemic events.

■ Hypertension history – Personal or family history of high blood pressure, with systolic blood pressure above 140 mmHg in repeated determinations.

■ Diabetes mellitus history – Diabetes is one of the risk factors in various heart diseases.

■ Stroke or TIA symptoms previously – Previous stroke or transitory ischemic accident puts the patient at higher risk of a new ischemic event if not under treatment.

■ Vascular disease history – A number of conditions, including atherosclerosis are deemed to be amongst the causes of stroke.

CHA2DS2 Vasc interpretation

The score provided by the form above shows the risk group in which the patient stands in terms of a future thromboembolic event, with an annual stroke risk given in percentage but also a risk of stroke, TIA or systemic embolism in percentage as well.

The study that created the model has shown that there is a proportional relationship between the score increase and the increase in risk of thromboembolic events within a year in patients who suffer from non-valvular AF and are not anticoagulated.

By comparison to the original CHADS2 it was shown that having three more variables accounted for, the VASc version automatically classifies more patients in the sensible high risk score groups. However, this doesn’t mean that the second version outperforms the first and usually clinicians can opt to use both in order to better discriminate the patients situation and the future treatment choice.

■ Scores of 0 are considered low risk and may not require anticoagulation.

■ Scores of 1 are considered low - moderate risk and might require antiplatelet or anticoagulation.

■ Scores of 2 and above are considerate moderate – high and high risk and require anticoagulation therapy.

CHA2DS2 Risk group Stroke risk TIA/Systemic embolism
0 Low 0.20% 0.78%
1 Low - Moderate 0.60% 2%
2 Moderate - High 2.20% 3.70%
3 High 3.20% 5.90%
4 High 4.80% 9.30%
5 High 7.20% 15.30%
6 High 9.70% 19.70%
7 High 11.20% 21.50%
8 High 10.80% 22.40%
9 High 12.20% 23.60%


1) Lip GY, Nieuwlaat R, Pisters R, Lane DA, Crijns HJ. (2010) 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; 137(2):263-72.

2) Ntaios G, Lip GY, Makaritsis K, Papavasileiou V, Vemmou A, Koroboki E, Savvari P, Manios E, Milionis H, Vemmos K. (2013) CHADS₂, CHA₂S₂DS₂-VASc, and long-term stroke outcome in patients without atrial fibrillation. Neurology; 80(11):1009-17.

3) Friberg L, Rosenqvist M, Gregory Y.H. (2012) Lip Evaluation of risk stratification schemes for ischaemic stroke and bleeding in 182 678 patients with atrial fibrillation: the Swedish Atrial Fibrillation cohort study. European Heart Journal; 1500-1510

07 Aug, 2015