CHADS₂ Score for Atrial Fibrillation Stroke Risk

id

40

full_title

CHADS₂ Score for Atrial Fibrillation Stroke Risk

short_title

CHADS₂ Score

med_description

Estimates stroke risk in patients with atrial fibrillation.

description

The CHADS2 score estimates stroke risk in patients with atrial fibrillation.

keywords

CHADS2, afib stroke, stroke risk, risk factors stroke, DM stroke, CHF stroke, age stroke, hypertension stroke, htn stroke, chads2 score, stroke risk score, chads stroke, chads afib stroke, chads score, chads calc, chads stroke risk, chads2 afib stroke, chads2 score, chads2 calc, chads2 stroke risk, afib stroke risk, chads stroke risk score, CHADS2 score for afib stroke, chads2 stroke afib, chads2 risk stroke, chads2 risk afib

complaint

[ "Palpitations", "Shortness of Breath", "Weakness" ]

formula

Addition of the selected points:

evidence

• Although in the initial derivation and validation studies a CHADS₂ score of 0 was associated with a low annual stroke risk of 1.9 and 0.8% respectively, subsequent studies have found that patients with a CHADS₂ score of 0 may have up to a 3.2% per year risk of ischemic stroke (Gage 2004).
• The derivation study, published in 2001, was a retrospective review of the National Registry of Atrial Fibrillation involving 1,733 patients and 2,121 patient years (Gage 2004).
  • It compared the performance of the CHADS₂ Score to two previously established stroke risk (AFI and SPAF III).
  • Found that CHADS₂ was the most accurate at predicting future stroke risk, with risk increasing by a factor of 1.5 for every additional point in a subject’s score.

• The validation study included 2,580 subjects with non-valvular AF who were started on aspirin and found that the CHADS₂ Score could successfully risk stratify patients (Gage 2001).
  • A score of 0 translated into a 0.8% annual stroke risk in this cohort, potentially making these patients appropriate for forgoing oral anticoagulation.
  • Patients with a score of 1-2 had a 2.7% annual stroke risk.
  • Patients with a score of 3 or more had a stroke risk of 5.3% up to 18.2% for subjects with a CHADS₂ score of 6.
• A study of the Danish National Patient Registry identified 146,251 patients with non-valvular AF and found that 47,576 had a CHADS₂ score of 0 or 1 (Olesen 2012).
  • 19,444 had a CHADS₂ score of 0 and the CHA₂DS₂-VASc Score was applied to these patients.
  • Authors found that in patients with a CHADS₂ score of 0 but a CHA₂DS₂-VASc score of 3 (if they had all three risk factors not accounted for by CHADS₂) that this cohort was at a 3.2% annual risk of stroke.
  • In contrast, patients with a CHA₂DS₂-VASc score of 0 was considered to be “truly low risk” with an annual ischemic stroke risk of 0.82%.
• Among 541 patients with non-valvular AF (of >48 hours duration) who underwent electrical cardioversion, 136 had a CHADS₂ score of 0 but 14 of those patients were found to have atrial thrombus on echocardiography, suggesting that the score missed 10% of patients who would have been at a high risk for a thromboembolic stroke after cardioversion (Yarmohammadi H 2012).

measurements

[]

information

See formula table, below:

refrences

{ "Clinical Practice Guidelines": [ { "href": "", "text": "" } ], "Manufacturer Website": [ { "href": "", "text": "" } ], "Original/Primary Reference": [ { "href": "https://www.ncbi.nlm.nih.gov/pubmed/11401607", "text": "Gage BF, Waterman AD, Shannon W, Boechler M, Rich MW, Radford MJ. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA. 2001 Jun 13;285(22):2864-70." } ], "Other References": [ { "href": "https://www.ncbi.nlm.nih.gov/pubmed/18574273", "text": "Singer DE, Albers GW, Dalen JE, Fang MC, Go AS, Halperin JL, Lip GY, Manning WJ; American College of Chest Physicians. Antithrombotic therapy in atrial fibrillation: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008 Jun;133(6 Suppl):546S-592S. doi: 10.1378/chest.08-0678." }, { "href": "https://www.ncbi.nlm.nih.gov/pubmed/22473219", "text": "Olesen JB, Torp-Pedersen C, Hansen ML, Lip GY. The value of the CHA2DS2-VASc score for refining stroke risk stratification in patients with atrial fibrillation with a CHADS2 score 0-1: a nationwide cohort study. Thromb Haemost. 2012 Jun;107(6):1172-9. doi: 10.1160/TH12-03-0175." }, { "href": "https://www.ncbi.nlm.nih.gov/pubmed/22503581", "text": "Yarmohammadi H, Varr BC, Puwanant S, Lieber E, Williams SJ, Klostermann T, Jasper SE, Whitman C, Klein AL. Role of CHADS2 score in evaluation of thromboembolic risk and mortality in patients with atrial fibrillation undergoing direct current cardioversion (from the ACUTE Trial Substudy). Am J Cardiol. 2012 Jul 15;110(2):222-6. doi: 10.1016/j.amjcard.2012.03.017." } ], "Outcomes": [ { "href": "", "text": "" } ], "Validation": [ { "href": "https://www.ncbi.nlm.nih.gov/pubmed/15477396", "text": "Gage BF, van Walraven C, Pearce L, Hart RG, Koudstaal PJ, Boode BS, Petersen P. Selecting patients with atrial fibrillation for anticoagulation: stroke risk stratification in patients taking aspirin. Circulation. 2004 Oct 19;110(16):2287-92. Epub 2004 Oct 11." } ], "Validations": [] }

pearls

MDCalc recommends the CHA₂DS₂-VASc Score over the original CHADS₂ Score to assess stroke risk in patients with atrial fibrillation. It risk stratifies these patients better than CHADS₂.

The CHADS₂ Score can help physicians estimate stroke risk in patients with non-valvular atrial fibrillation and determine which antithrombotic therapy is most appropriate.

• Studies have found that as the CHADS₂ Score increases, the annual risk of ischemic stroke increases proportionally.
• Patients with high CHADS₂ scores (>2) are at significant risk for stroke: 5.9% annual risk with a score of 3; up to 18.2% annual stroke risk for patients with a score of 6.
  • It is generally recommended that patients with a score >2 be started on warfarin, as the benefits of ischemic stroke prevention outweigh the bleeding risk.
• According to some studies, patients with a CHADS₂ score of 0 may be at low enough stroke risk (0.8-3.2% annual risk) that they can take aspirin (325mg) rather than warfarin as antithrombotic therapy.

Points to keep in mind:

• More recent studies suggest that CHADS₂ of 0 points is not necessarily “low-risk” (still 3.2% incidence of stroke per year.)
• The more recently developed CHA₂DS₂-VASc Score takes into account other stroke risk factors and may be able to accurately identify which patients are at low enough stroke risk to forgo oral anticoagulation.
• Among patients aged 65-95 years old with non-valvular atrial fibrillation, very few (<7%) will be classified as low risk according to the CHADS₂ Score.
• The CHADS₂ Score does not perform well in the risk stratification of patients with AF who are receiving outpatient elective electric cardioversion.
  • In one study, 10% of patients with a score of zero were found to have left atrial appendage thrombi on transesophageal echocardiography.

usecase

The CHADS₂ Score is one of several risk stratification schema that can help determine the 1 year risk of an ischemic stroke in a non-anticoagulated patient with non-valvular AF.

reasons

The risk stratification provided by the CHADS₂ Score may help physicians make more informed and personalized decisions about whether the risks and benefits of initiating antithrombotic therapy.

next_advice

• Consider applying the CHA₂DS₂-VASc Score to patients with a CHADS₂ score of 0 in order to further risk stratify these patients.

next_actions

One recommendation suggests a 0 score is low risk and may not require anticoagulation, however there is literature that suggests that not all patients with a CHADS₂ score of 0 are at low risk for ischemic stroke.

• Consider using the CHA₂DS₂-VASc Score to further risk stratify patients who are identified as low risk by their CHADS₂ score.
• For patients who are identified as moderate (score 1-2) or high risk for ischemic stroke (>3), anticoagulation therapy should be considered.
• For those patients in whom anticoagulation is considered, bleeding risk scores such as ATRIA, HAS-BLED or HEMORR₂HAGES can be used to determine the risk for warfarin-associated hemorrhage.
• Carefully consider all the risks and benefits prior to initiating anticoagulation in patients with non-valvular AF.

next_management

diseases

[ "Arrhythmia", "Atrial Fibrillation", "Stroke / Transient Ischemic Attack (TIA)" ]

instructions

published

2022-04-21T20:29:34.608Z

purpose

[ "Prognosis", "Treatment" ]

search_terms

[ "tia", "afib", "chads", "stroke", "cva", "atrial fibrillation", "stroke risk", "chads2" ]

seo

{ "keywords_en": "CHADS2, afib stroke, stroke risk, risk factors stroke, DM stroke, CHF stroke, age stroke, hypertension stroke, htn stroke, chads2 score, stroke risk score, chads stroke, chads afib stroke, chads score, chads calc, chads stroke risk, chads2 afib stroke, chads2 score, chads2 calc, chads2 stroke risk, afib stroke risk, chads stroke risk score, CHADS2 score for afib stroke, chads2 stroke afib, chads2 risk stroke, chads2 risk afib", "meta_description_en": "The CHADS2 score estimates stroke risk in patients with atrial fibrillation." }

specialty

[ "Cardiology", "Critical Care", "Emergency Medicine", "Family Practice", "Geriatrics", "Hospitalist Medicine", "Internal Medicine", "Neurology", "Primary Care" ]

departments

[ "Cardiac", "Neurologic" ]

tags

[]

version_number

1

versions

[]

related

[ { "calcId": 801, "short_title_en": "CHA₂DS₂-VASc Score", "slug": "cha2ds2-vasc-score-atrial-fibrillation-stroke-risk" }, { "calcId": 807, "short_title_en": "HAS-BLED Score", "slug": "has-bled-score-major-bleeding-risk" }, { "calcId": 10583, "short_title_en": "CHA₂DS₂-VA Score", "slug": "cha2ds2-va-score-atrial-fibrillation-stroke-risk" } ]

ismed

true

section

[ "whenToUseViewed", "pearlsPitfallsViewed", "whyUseViewed", "nextStepsViewed", "evidenceViewed" ]

cleaned_departments

[ "cardiology", "neurology" ]

cleaned_use

[ "The CHADS₂ Score is one of several risk stratification schema that can help determine the 1 year risk of an ischemic stroke in a non-anticoagulated patient with non-valvular AF." ]

pub

true