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CHADS2 scoring system

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  • the long-term risk of stroke in valvular atrial fibrillation (AF) depends on clinical predictors, which are collectively assessed in the CHADS2 scoring scheme, an acronym for Congestive heart failure,hypertension, Age>75, Diabetes mellitus, and prior Stroke (1):

CHADS2 Scoring Scheme

  Condition Points
C Congestive heart failure 1
H Hypertension 1
A Age > 75 years 1
D Diabetes Mellitus 1
S2 Prior Stroke or TIA 2

Annual Stroke Risk with Respect to CHADS 2 Score (1)

CHADS2 Score Stroke Risk % 95% confidence interval
0 1.9 1.2-3.0
1 2.8 2.0-3.8
2 4.0 3.1-5.1
3 5.9 4.6-7.3
4 8.5 6.3-11.1
5 12.5 8.2-17.5
6 18.2 10.5-27.4

Anticoagulation based on the CHADS2 score

Score Risk Anticoagulation Therapy Considerations
0 Low Aspirin or no treatment No antithrombotic therapy (or aspirin)
1 Moderate Aspirin or Warfarin Aspirin daily or raise INR to 2.0-3.0, depending on factors such as patient preference
2 or greater Moderate or High Warfarin Raise INR to 2.0-3.0, unless contraindicated (e.g. clinically significant GI bleeding, inability to obtain regular INR screening)

To complement the CHADS2 score, by the inclusion of additional 'stroke risk modifier' risk factors, the CHA2DS2-VASc score was developed (2)

  • these additional 'clinically relevant non-major' stroke risk factors include age 65-74, female gender and vascular disease

  • in the CHA2DS2-VASc score score, 'age 75 and above' also has extra weight, with 2 points

CHA2DS2-VASc score for stroke risk in atrial fibrillation

Feature Score
Congestive Heart Failure 1
Hypertension 1
Age >75 years 2
Age between 65 and 74 years 1
Stroke/TIA/TE 2
Vascular disease (previous MI, peripheral arterial disease or aortic plaque) 1
Diabetes mellitus 1
Female 1

NICE suggest (3):

  • use the CHA2DS2-VASc stroke risk score to assess stroke risk in people with any of the following:
    • symptomatic or asymptomatic paroxysmal, persistent or permanent atrial fibrillation
    • atrial flutter
    • a continuing risk of arrhythmia recurrence after cardioversion back to sinus rhythm
  • do not offer stroke prevention therapy to people aged under 65 years with atrial fibrillation and no risk factors other than their sex (that is, very low risk of stroke equating to a CHA2DS2-VASc score of 0 for men or 1 for women)

  • anticoagulation

    • anticoagulation may be with apixaban, dabigatran etexilate, rivaroxaban or a vitamin K antagonist

      • consider anticoagulation for men with a CHA2DS2-VASc score of 1. Take the bleeding risk into account

      • offer anticoagulation to people with a CHA2DS2-VASc score of 2 or above, taking bleeding risk into account

      • discuss the options for anticoagulation with the person and base the choice on their clinical features and preferences