CHADS2, Stroke Rate

Stratification schemes for Prevention of Stroke in Nonvalvular Atrial Fibrillation (Gage, 2001)

Score determined by CHF, HTN, Age>75, and/or diabetes = 1; stroke/TIA = 2

Think CHADS2(2): A chad score of 2 is moderate risk and you have 2 options, ASA or Warfarin; < 2 is ASA, >2 is warfarin

CHADS2 Score Risk Stroke Rate Per Year %
0 Low 1
1 Low 1.5
2 Moderate 2
3 High 5
≥ Very High 7

 

Prevention of Stroke in Nonvalvular Atrial Fibrillation - Recommendations

Prevention Risk Group Recommended Prevention Range of Management
Primary Prevention Long Atrial Fibrillation
< 60y		 None ASA 325
Low Risk ASA 325 Warfarin, INR 1.6-3
Moderate Risk Warfarin, INR 1.6-3
or ASA 325		  
High Risk < 75y Warfarin, INR 2-3 ASA if warfarin contraindicated
High Risk >75y Warfarin, INR 1.6-2.5 ASA if warfarin contraindicated
Secondary Prevention Warfarin, INR 2-3 ASA if warfarin contraindicated

 

CHADS2 Score

Stroke with warfarin

Stroke without warfarin

 NNT

0                 low risk

0.25

0.49

 417

1                 int risk

0.72

1.52

 125

2                 int risk

1.27

2.50

 81

3                 high risk

2.20

5.27

 33

4                 high risk

2.35

6.02

 27

5 or 6          high risk

4.60

6.88

 44