CHADS2 score

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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 CHADS2 score, that is used to estimate stroke risk.

In clinical use, the CHADS2 score has been superseded by the CHA2DS2-VASc score that gives a better stratification of low-risk patients.

Stroke risk assessment, and antithrombotic therapy[edit]

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, '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 rivaroxaban or 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 of 2 or more), OAC is recommended; and (ii) If there is 1 risk factor (essentially a CHA2DS2-VASc score=1), antithrombotic therapy with OAC or aspirin (OAC preferred) is recommended, and patient values and preferences should be considered.

A CHA2DS2-VASc 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[edit]

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

Treatment strategies recommended based on the CHADS2 score are shown in the table.[1][2]

How the treatment recommendations based on the CHADS2 score are modified by considering additional 'stroke risk modifier' risk factors using the CHA2DS2-VASc score, see ESC guideline recommendations, which recommend the management as shown in the following table:(table is outdated and using this table may result in patient harm)

CHA2DS2-VASc[edit]

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 sex)
1

The CHA2DS2-VASc[12][13][14] score is a refinement of CHADS2[15][16] score and extends the latter by including additional common stroke risk factors, as discussed below.

The maximum CHADS2 score is 6, 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). Note that female gender only scores one point if the patient has at least one other risk factor, and does not score any points in isolation.

Stroke risk assessment[edit]

Annual Stroke Risk[17]
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
??
-
9
15.2
-

Anticoagulation[edit]

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. rivaroxaban or 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][18]

Limitations of stroke risk prediction tools[edit]

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.[19][20]

References[edit]

  1. ^ a b Gage BF, van Walraven C, Pearce L, et al. (2004). "Selecting patients with atrial fibrillation for anticoagulation: stroke risk stratification in patients taking aspirin". Circulation 110 (16): 2287–92. doi:10.1161/01.CIR.0000145172.55640.93. PMID 15477396. 
  2. ^ a b c Gage BF, Waterman AD, Shannon W, Boechler M, Rich MW, Radford MJ (2001). "Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation". JAMA 285 (22): 2864–70. doi:10.1001/jama.285.22.2864. PMID 11401607. 
  3. ^ "Risk of Stroke with AF". VA Palo Alto Medical Center and at Stanford University: the Sportsmedicine Program and the Cardiomyopathy Clinic. Retrieved 2007-09-14. 
  4. ^ Karthikeyan G, Eikelboom JW. The CHADS2 score for stroke risk stratification in atrial fibrillation--friend or foe? Thromb Haemost. 2010 Jul 5;104(1):45-8.
  5. ^ Lip GY, Nieuwlaat R, Pisters R, Lane DA, Crijns HJ. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: the euro heart survey on atrial fibrillation. Chest. 2010 Feb;137(2):263-72.
  6. ^ European Heart Rhythm Association; European Association for Cardio-Thoracic Surgery, Camm AJ, Kirchhof P, Lip GY, Schotten U, Savelieva I, Ernst S, Van Gelder IC, Al-Attar N, Hindricks G, Prendergast B, Heidbuchel H, Alfieri O, Angelini A, Atar D, Colonna P, De Caterina R, De Sutter J, Goette A, Gorenek B, Heldal M, Hohloser SH, Kolh P, Le Heuzey JY, Ponikowski P, Rutten FH. Guidelines for the management of atrial fibrillation: the Task Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC). Eur Heart J. 2010 Oct;31(19):2369-429.
  7. ^ a b http://www.escardio.org/guidelines-surveys/esc-guidelines/Pages/atrial-fibrillation.aspx
  8. ^ Olesen JB, Lip GY, Hansen ML, Hansen PR, Tolstrup JS, Lindhardsen J, Selmer C, Ahlehoff O, Olsen AM, Gislason GH, Torp-Pedersen C. Validation of risk stratification schemes for predicting stroke and thromboembolism in patients with atrial fibrillation: nationwide cohort study. BMJ. 2011 Jan 31;342:d124. doi:10.1136/bmj.d124.
  9. ^ Van Staa, TP, Setakis, E, Di Tanna, GL, Lane, DA, Lip, GY (October 2010). "A comparison of risk stratification schema for stroke in 79884 atrial fibrillation patients in general practice". J Thromb Haemost. 9 (1): 39–48. doi:10.1111/j.1538-7836.2010.04085.x. PMID 21029359. 
  10. ^ Lip, GY, Halperin, JL. (Jun 2010). "Improving stroke risk stratification in atrial fibrillation". Am J Med. 123 (6): 484–8. doi:10.1016/j.amjmed.2009.12.013. PMID 20569748. 
  11. ^ Cairns JA, Connolly S, McMurtry S, Stephenson M, Talajic M; CCS Atrial Fibrillation Guidelines Committee. Canadian Cardiovascular Society atrial fibrillation guidelines 2010: prevention of stroke and systemic thromboembolism in atrial fibrillation and flutter. Can J Cardiol. 2011 Jan-Feb;27(1):74-90. PMID 21329865.
  12. ^ http://www.mdcalc.com/cha2ds2-vasc-score-for-atrial-fibrillation-stroke-risk/
  13. ^ http://www.saheart.com.au/for-doctors/clinical-tools/cha2ds2-vasc-score.html
  14. ^ http://www.gpnotebook.co.uk/simplepage.cfm?ID=x20110126111352933383
  15. ^ http://heart.bmj.com/content/early/2011/11/10/heartjnl-2011-300901.abstract
  16. ^ http://journal.publications.chestnet.org/article.aspx?articleid=1086288
  17. ^ "Prevention of stroke in patients with atrial fibrillation: current strategies and future directions". British Medical Journal. Retrieved 30 December 2012. 
  18. ^ Eckman MH, Singer DE, Rosand J, Greenberg SM. Moving the tipping point: the decision to anticoagulate patients with atrial fibrillation. Circ Cardiovasc Qual Outcomes. 2011 Jan 1;4(1):14-21.
  19. ^ Ferguson C, Inglis SC, Newton PJ, Middleton S, Macdonald PS, Davidson PM. Atrial fibrillation and thromboprophylaxis in heart failure: the need for patient-centered approaches to address adherence. Vascular Health & Risk Management. 2013 (9) : 3-11.
  20. ^ http://www.dovepress.com/atrial-fibrillation-and-thromboprophylaxis-in-heart-failure-the-need-f-peer-reviewed-article-VHRM

External links[edit]