World Library  
Flag as Inappropriate
Email this Article

CHADS2 score

Article Id: WHEBN0013265003
Reproduction Date:

Title: CHADS2 score  
Author: World Heritage Encyclopedia
Language: English
Subject: Anticoagulant, Dabigatran, Atrial fibrillation
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

CHADS2 score

For other uses, see Chad (disambiguation).
Condition Points
 C   Congestive heart failure
1
 H  Hypertension: blood pressure consistently above 140/90 mmHg (or treated hypertension on medication)
1
 A  Age ≥75 years
1
 D  Diabetes mellitus
1
 S2  Prior Stroke or TIA or Thromboembolism
2

The CHADS2 score is a clinical prediction rule for estimating the risk of stroke in patients with non-rheumatic atrial fibrillation (AF), a common and serious heart arrhythmia associated with thromboembolic stroke. It is used to determine whether or not treatment is required with anticoagulation therapy or antiplatelet therapy,[1] since AF can cause stasis of blood in the upper heart chambers, leading to the formation of a mural thrombus that can dislodge into the blood flow, reach the brain, cut off supply to the brain, and cause a stroke. A high CHADS2 score corresponds to a greater risk of stroke, while a low CHADS2 score corresponds to a lower risk of stroke. The CHADS2 score is simple and has been validated by many studies.[2]

The CHADS2 scoring table is shown above:[3] adding together the points that correspond to the conditions that are present results in the CHA2DS2 score, that is used to estimate stroke risk.

In clinical use, the CHA2DS2 score has been superseded by the CHA2DS2-VASc score that gives a better stratification of low-risk patients.

Stroke risk assessment, and antithrombotic therapy

Annual Stroke Risk[2]
CHADS2 Score Stroke Risk % 95% CI
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

According to the findings of the initial validation study, the risk of stroke as a percentage per year for the CHADS2 score is shown in the table.

The CHADS2 score does not include some common stroke risk factors and its various pros/cons have been carefully discussed.[4] Nonetheless, this score is simple and thus it has become widely used.

To complement the CHADS2 score, by the inclusion of additional 'stroke risk modifier' risk factors, the CHA2DS2-VASc score has been proposed.[5] These additional 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.

The CHA2DS2-VASc score has been used in the new European Society of Cardiology guidelines for the management of atrial fibrillation.[6][7]

The European Society of Cardiology (ESC) guidelines recommend that if the patient has a CHADS2 score of 2 and above, oral anticoagulation therapy (OAC) such as warfarin (target INR of 2-3) or one of the new OAC drugs (such as dabigatran) should be prescribed.

If the CHADS2 score is 0-1, other stroke risk modifiers could be considered: (i) If there are 2 or more risk factors (essentially a CHA2DS2-VASc score score of 2 or more), OAC is recommended; and (ii) If there is 1 risk factor (essentially a CHA2DS2-VASc score score=1), antithrombotic therapy with OAC or aspirin (OAC preferred) is recommended, and patient values and preferences should be considered.

A CHA2DS2-VASc score score=0 corresponds to a 'truly low risk,’[8][9] and thus the recommendation is to prescribe either aspirin or no antithrombotic therapy, but 'no antithrombotic therapy' is preferred.[10]

Stroke risk assessment should always include an assessment of bleeding risk. This can be done using validated bleeding risk scores, such as the HEMORR2HAGES or HAS-BLED scores. The latter is recommended in the ESC and Canadian guidelines.[11] If the patient is taking warfarin, then knowledge of INR control is needed to assess the 'labile INR' criterion in HAS-BLED; otherwise for a non-warfarin patient, this scores zero.

Anticoagulation

Score Risk Anticoagulation Therapy Considerations
0 Low None or Aspirin Aspirin daily
1 Moderate Aspirin or Warfarin Aspirin daily or raise INR to 2.0-3.0, depending on patient preference
2 or greater Moderate or High Warfarin Raise INR to 2.0-3.0, unless contraindicated

Treatment strategies recommended based on the CHA2DS2 score are shown in the table.[1][2]

How the treatment recommendations based on the CHA2DS2 score are modified by considering additional 'stroke risk modifier' risk factors using the ESC guideline recommendations, which recommend the management as shown in the following table:

CHA2DS2-VASc

Condition Points
 C   Congestive heart failure (or Left ventricular systolic dysfunction)
1
 H  Hypertension: blood pressure consistently above 140/90 mmHg (or treated hypertension on medication)
1
 A2  Age ≥75 years
2
 D  Diabetes Mellitus
1
 S2  Prior Stroke or TIA or thromboembolism
2
 V  Vascular disease (e.g. peripheral artery disease, myocardial infarction, aortic plaque)
1
 A  Age 65–74 years
1
 Sc  Sex category (i.e. female gender)
1

The CHA2DS2-VASc score is a refinement of CHA2DS2 score and extends the latter by including additional common stroke risk factors, as discussed below.

The maximum CHA2DS2 score is 7, whilst the maximum CHA2DS2-VASc score is 9 (for age, either the patient is ≥75 years and gets two points, is between 65-74 and gets one point, or is under 65 and does not get points).

Stroke risk assessment

Annual Stroke Risk[12]
CHA2DS2-VASc Score Stroke Risk % 95% CI
0
0
-
1
1.3
-
2
2.2
-
3
3.2
-
4
4.0
-
5
6.7
-
6
9.8
-
7
9.6
-
8
6.7
-
9
15.2
-

Anticoagulation

Score Risk Anticoagulation Therapy Considerations
0 Low No antithrombotic therapy (or Aspirin) No antithrombotic therapy (or Aspirin 75–325 mg daily)
1 Moderate Oral anticoagulant (or Aspirin) Oral anticoagulant, either new oral anticoagulant drug e.g. dabigatran or well controlled warfarin at INR 2.0-3.0 (or Aspirin 75–325 mg daily, depending on factors such as patient preference)
2 or greater High Oral anticoagulant Oral anticoagulant, using either a new oral anticoagulant drug (apixaban, rivaroxaban or dabigatran) or well controlled warfarin at INR 2.0-3.0

Based on the ESC guidelines on Atrial Fibrillation, oral anticoagulation is recommended or preferred for patients with one or more stroke risk factors (i.e. a CHA2DS2-VASc score of 1 and above). This is consistent with a recent decision analysis model showing how the 'tipping point' on the decision to anticoagulate has changed with the availability of new 'safer' OAC drugs.[7][13]

Limitations of stroke risk prediction tools

Current stroke risk prediction tools including the CHADS2 and CHA2DS2VASc models are helpful in clinical practice. However, these are limited within the context of complex cardiogeriatric syndromes. Expanding such models to consider frailty, cognitive and functional decline, or nonadherence to anticoagulant therapy is warranted. Although avoiding stroke is an important consideration, the potential adverse effects of treatment needs to be balanced within the context of best available evidence, clinical expertise, and the individual patient’s circumstances. Developing metrics that consider the combination of these factors are likely to shed light on the issues of adherence in this population.[14][15]

References

External links

  • CHADS2 online calculator
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.