CHADS2:   Atrial Fibrillation Stroke Risk Assessment

(Non-Valvular Heart Disease; incorporating Canadian Cardiovascular Society Guidelines 2014)

Patient name:
Date:
Patients age:

Associated medical conditions: Absent Present

Congestive heart failure within 90 days

HTN - whether on treatment or not

Age ≥ 75yrs

Diabetes

Stroke or TIA - at any time

     

CHADS2 Score Yearly Risk of Stroke Event rate off warfarin (% per year) Event rate on warfarin (% per year) NNT
0 1.9% (1.2-3.0) 0.49 0.25 417
1 2.8% (2.0-3.8) 1.52 0.72 125
2 4.0% (3.1-5.1) 2.50 1.27 81
3 5.9% (4.6-7.3) 5.27 2.20 33
4 8.5% (6.3-11.1) 6.02 2.35 27
5 12.5% (8.2-17.5) 6.88 4.60 44
6 18.2% (10.5-27.4) - - -

Risk of major bleed Less significant but worrisome bleed
Age < 80yrs: risk of major bleed 1% per year. Age > 50yrs: risk of minor bleed 5% per year.
Age > 80 yrs: risk of major bleed 3.4% per year.

CHADS2 Score Consideration
0 Low Risk of stroke (<2%). Treat with ASA if CAD/AVD present. Otherwise no OAC if < 65.
1-6 Higher Risk of stroke. Recommend OAC. Discuss risks and benefits.

Notes:
1. Check TSH: hyperthyroidism is a major cause of atrial fibrillation.
2. Echocardiogram to determine existence of LV dysfunction, and presence of intra-cardiac thrombus.
3. Establish rate control with either B-blocker or a calcium channel blocker.
4. Treatment with warfarin reduces the risk of stroke in atrial fibrillation by about 66% compared to aspirin, about 22%. See AF advisor
5. The risk of major bleeding on warfarin varies with the patients medical problems but is generally less than 2%. See CHADS-VASC and HAS-BLEED eForm.

Subject:

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