CHADS2 score for risk of thromboembolism in atrial fibrillation

CHADS2 score for risk of thromboembolism in atrial fibrillation

CHADS₂ score was developed to assess the risk of thromboembolism in nonvalvular atrial fibrillation [1]. Scores were allotted to various risk factors as follows:

• Congestive heart failure: 1
• History of hypertension: 1
• Age > 75:    1
• Diabetes: 1
• Stroke / TIA: 2

Anticoagulation (typically Warfarin) is indicated when CHADS₂ score is 2 or more. That would mean that anyone who had stroke or transient ischemic attack (TIA) along with atrial fibrillation will need life long anticoagulation.

As age above 75 is a risk factor, any one of hypertension, diabetes mellitus or congestive heart failure in this age group will become an indication for anticoagulation.

Valvar atrial fibrillation is considered as atrial fibrillation in the presence of mitral stenosis or artificial heart valves. Other valvular lesions like mitral regurgitation, aortic stenosis and regurgitation do not result in low flow in left atrium [2]. In valvar atrial fibrillation only vitamin K dependent oral anticoagulants are considered while in non valvar atrial fibrillation, non vitamin K dependent oral anticoagulants (NOACs) can also be considered.

References

1. 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.
2. Fauchier L, Philippart R, Clementy N, Bourguignon T, Angoulvant D, Ivanes F, Babuty D, Bernard A. How to define valvular atrial fibrillation? Arch Cardiovasc Dis. 2015 Oct;108(10):530-9.