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Assessing stroke risk – easier than saying “CHA2DS2-VA Score”!

General Practitioner Dr Vivienne Miller takes a look at what’s changed in the recently updated CHA2DS2-VASC Score for the determination of stroke risk factors from atrial fibrillation.

The CHA2DS2-VA Score was updated from the CHA2DS2-VASC Score last year to exclude female sex (represented by Sc) in the determination of stroke risk factors from atrial fibrillation. The two scores are identical, apart from the exclusion of female sex, which is no longer considered an outright risk factor in stroke from atrial fibrillation, but more of a ‘risk modifier’ of this complication.1

This means that females being assessed of stroke risk would have an extra point on their score because of their sex, and hence would be more likely to be recommended to have anticoagulation when assessed at being at very low risk. Women with atrial fibrillation are overall at higher risk of stroke compared to men. This is particularly so when they scored 1 to 6 (but strangely, not 3) on the older CHA2DS2-VASC Score.1

Patients at increased thromboembolic risk who have atrial fibrillation (CHA2DS2-VA scores of two or more, and in some cases, scores of one) should be fully anticoagulated unless this is contraindicated. Aspirin is inappropriate and should not be used for this indication, but is still very much used in low dose for the secondary prevention of cardiovascular events.

Modern treatment would usually now be commencement using a novel oral anticoagulant (NOAC). Warfarin is still used in certain patients, for example, those with end-stage renal failure (e GFRF < 25ml/min), although this is debated.2 Patients who have moderate to severe mitral stenosis or an artificial heart valve should also receive warfarin as there is a lack of evidence for NOAC efficacy in these conditions.2

In the updated version (the CHA2DS2-VA Score):

 The CHA2DS2-VA Score (which was updated from the CHA2DS2-VASC Score in 2018)3

CONDITION Points
 C Congestive heart failure: recent signs, symptoms or admission for decompensated heart failure; this includes both HFREF* and HFPEF**, or moderately to severely reduced systolic left ventricular function, whether or not there is a history of heart failure. 1
 H History of hypertension, whether or not blood pressure is currently elevated. 1
 A2  Age 75 years or older 2
 D  Diabetes Mellitus 1
 S2  Stroke in the past, or a history of transient ischaemic attack or thromboembolism. 2
 V Vascular disease, defined as prior myocardial infarction or peripheral arterial disease or complex aortic atheroma or plaque on imaging (if performed). 1
 A  Age 65 to 74 years 1
*Heart failure with reduced ejection fraction

**Heart failure with preserved ejection fraction

 

The following annual stroke risk used the older CHA2DS2-VASc Score but is unlikely to be updated now that female sex has been removed. The risk assessment is only approximate and there is a large confidence interval, and so the inclusion or exclusion of female sex is unlikely to make a substantial difference to an individual.4

 

Annual Stroke Risk by CHA2DS2-VASc Score

CHA2DS2-VASC2 ScoreSTROKE RISK% (95% Confidence interval)
00
11.3
22.2
33.2
44
56.7
69.8
79.6
812.5
915.2

 

References

  1. Nielsen PB, Skjøth F, Overvad TF, Larsen TB, Lip GYH. Female Sex Is a Risk Modifier Rather Than a Risk Factor for Stroke in Atrial Fibrillation: Should We Use a CHA2DS2-VA Score Rather Than CHA2DS2-VASc? Circulation. 2018 Feb 20; 137(8): 832-40. DOI: 10.1161/CIRCULATIONAHA.117.029081
  2. Heine GH1, Brandenburg V, Schirmer SH. Oral Anticoagulation in Chronic Kidney Disease and Atrial Fibrillation.The Use of Non-Vitamin K-Dependent Anticoagulants and Vitamin K Antagonists.  Dtsch Arztebl Int. 2018 Apr 27; 115(17): 287–94.
  3. National Heart Foundation of Australia and the Cardiac Society of Australia and New Zealand. Heart Foundation [Internet]. Sydney NSW: National Heart Foundation of Australia. Table 3: Definitions and points in the CHA2DS2- VA Score. 2018 Aug 1. Available from: https://www.heartfoundation.org.au/images/uploads/publications/Table_3_Definitions_and_points_in_the_CHA2DS2-VA_score.pdf
  4. Prof David Brieger – personal communication August 2019.