Society Guidelines
The 2014 Atrial Fibrillation Guidelines Companion: A Practical Approach to the Use of the Canadian Cardiovascular Society Guidelines

https://doi.org/10.1016/j.cjca.2015.06.005Get rights and content

Abstract

The Canadian Cardiovascular Society (CCS) Atrial Fibrillation Guidelines Program has generated a comprehensive series of documents regarding the management of atrial fibrillation (AF) between 2010 and 2014. The guidelines provide evidence-based consensus management recommendations in a broad range of areas. These guidelines have proven useful in informing clinical practice, but often lack detail in specifications related to practical application, particularly for areas in which the evidence base is limited or conflicting. Based on feedback from the community, the CCS Atrial Fibrillation Guidelines Committee has identified a number of areas that require clarification to address commonly asked practical questions related to guidelines application. In the present article a number of such questions are presented and suggestions about how they can be answered are suggested. Among the issues considered are: (1) What duration of AF is clinically significant? (2) How are the risk factors in the CCS Algorithm for selecting anticoagulation therapy derived and defined? (3) How is valvular heart disease defined and how do different forms of valve disease affect the choice of anticoagulant therapy for AF patients? (4) How should we quantify renal dysfunction and how does it affect therapeutic choices? The response to these questions and the underlying logic are provided, along with an indication of future research needed where no specific approach can presently be recommended based on the literature.

Résumé

Entre 2010 et 2014, le programme de Lignes directrices de la Société canadienne de cardiologie (SCC) en matière de fibrillation auriculaire (FA) a permis de créer une série de documents détaillés sur la prise en charge de cette affection. Les lignes directrices contiennent des recommandations consensuelles de prise en charge fondées sur des données probantes dans plusieurs sphères d’application. Bien qu’informatives pour la pratique clinique, les lignes directrices manquent parfois de précision quant aux questions d’ordre pratique, particulièrement lorsque les données probantes sont limitées ou conflictuelles. À la suite de rétroactions fournies par la communauté médicale, le comité des lignes directrices en matière de fibrillation auriculaire a établi un certain nombre de sujets devant être clarifiés pour répondre aux questions d’ordre pratique fréquemment posées sur l’application des lignes directrices. Vous trouverez dans cet article un certain nombre de questions et des pistes de réponses possibles, notamment : 1) Quelle est la durée d’une FA cliniquement significative? 2) Comment les facteurs de risque de l’algorithme de la SCC pour la sélection d’un traitement anticoagulant sont-ils déterminés et définis? 3) Quelle est la définition de la valvulopathie et comment les différentes formes de cette affection influent-elles sur le choix du traitement anticoagulant chez les patients atteints de FA? 4) Comment quantifier la dysfonction rénale et quelle est son incidence sur les choix thérapeutiques? Vous obtiendrez des réponses à toutes ces questions en plus de prendre connaissance de la logique qui les sous-tend. Vous obtiendrez aussi des indications relativement aux études cliniques qui seront nécessaires pour valider les approches qui ne peuvent actuellement être fondées sur des données probantes.

Section snippets

What Duration of AF Is Clinically Significant?

The detection of an irregularly irregular heart rhythm on heart rhythm monitoring (eg, via ambulatory electrocardiogram [ECG] or implantable electronic device) suggests a diagnosis of AF. There is extensive evidence for a relationship between the duration of AF paroxysms and stroke risk.4, 5 Oral anticoagulation with vitamin-K antagonists or a novel non-vitamin K antagonists (NOACs) reduce stroke risk, but carry the disadvantages of increased risk of bleeding, cost, and/or a need for

How Were the Risk Factors in the CCS Algorithm Derived?

The accuracy of various schemas for the prediction of stroke risk in patients with nonvalvular AF (NVAF), the validity of their individual components for estimation of annual stroke incidence, and differences among national guidelines with respect to their recommendations for antithrombotic therapies are actively debated.11, 12, 13 Accordingly, it is timely to review the origins of the most widely used risk prediction schemas and the data underlying recommendations for antithrombotic therapies.

Validation of Risk Prediction Schema

The CHADS2 index was validated in a cohort of 1733 US Medicare recipients aged 65-95 years, who had nonrheumatic AF documented during an index hospitalization, and who were not prescribed warfarin at hospital discharge.17 Patients were followed for a median of 1 year for the outcome of hospitalization for ischemic stroke or TIA.

Subsequently, the CHADS2 index and CHA2DS2-VASc schema have been validated in a cohort of patients in the Euro Heart Survey aged ≥ 18 years, who were free of mitral

What Are the Definitions of Stroke Risk Factors in the CCS Atrial Fibrillation Guidelines Update?

The 2014 CCS Atrial Fibrillation Guidelines update used the CHADS2 index with the evolved definitions of its component risk factors for stroke (termed the CCS Algorithm).3 The evolved definitions were not explicitly stated in the CCS Atrial Fibrillation Guideline update and are now detailed in Table 1. Female sex was not considered to be an independent risk factor, in agreement with the ESC 2012 guidelines.21

The estimates for annual risks of the outcome of “stroke” used in the 2014 CCS update

What is the current definition of NVAF?

The term “nonvalvular AF” has been used for at least 35 years29 but has never been satisfactorily defined. In the 1950s, observational reports suggested that AF was associated with a very high risk of thromboembolic events in patients with rheumatic mitral stenosis, the most common form of chronic valvular heart disease (VHD) at the time. Further reports suggested that this risk could be reduced with the use of a VKA.30, 31 In the late 1970s and early 1980s it was recognized that AF was

How should we measure renal function?

The serum concentration of creatinine, a by-product of the metabolism of creatine and phosphocreatine in skeletal muscle is, in steady state, a fairly reliable indicator of kidney function. Unfortunately, the use of serum creatinine level is limited by its indirect relationship to glomerular filtration. The production of serum creatinine is proportional to muscle mass (which is modified by factors such as sex, age, muscle mass, race, and nutrition), and the clearance of creatinine is influenced

Conclusions

There are clearly many major practical questions about the application of AF guidelines that remain unanswered. We have attempted to provide expert guidance wherever possible, but on some issues (notably the duration of AF paroxysms at which anticoagulation should be instituted), only future research will provide adequate guidance.

References (62)

  • G.W. Petty et al.

    Outcomes among valvular heart disease patients experiencing ischemic stroke or transient ischemic attack in Olmsted county, Minnesota

    Mayo Clin Proc

    (2005)
  • M. Ruel et al.

    Late incidence and determinants of stroke after aortic and mitral valve replacement

    Ann Thorac Surg

    (2004)
  • H. Nakagami et al.

    Mitral regurgitation reduces the risk of stroke in patients with nonrheumatic atrial fibrillation

    Am Heart J

    (1998)
  • L. Gonzalez-Lavin et al.

    The risk of thromboembolism and hemorrhage following mitral valve replacement. A comparative analysis between the porcine xenograft valve and Ionescu-Shiley bovine pericardial valve

    J Thorac Cardiovasc Surg

    (1984)
  • M.D. Ezekowitz et al.

    Comparison of dabigatran versus warfarin in patients with atrial fibrillation and valvular heart disease: the RE-LY trial [abstract]

    J Am Coll Cardiol

    (2014)
  • L.A. Stevens et al.

    Comparative performance of the CKD Epidemiology Collaboration (CKD-EPI) and the Modification of Diet in Renal Disease (MDRD) study equations for estimating GFR levels above 60 mL/min/1.73 m2

    Am J Kidney Dis

    (2010)
  • A.N. Bonde et al.

    Net clinical benefit of antithrombotic therapy in patients with atrial fibrillation and chronic kidney disease: a nationwide observational cohort study

    J Am Coll Cardiol

    (2014)
  • T.V. Glotzer et al.

    The relationship between daily atrial tachyarrhythmia burden from implantable device diagnostics and stroke risk: The TRENDS study

    Circ Arrhythm Electrophysiol

    (2009)
  • J.S. Healey et al.

    Subclinical atrial fibrillation and the risk of stroke

    N Engl J Med

    (2012)
  • H. Calkins et al.

    2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design: a report of the Heart Rhythm Society (HRS) task force on catheter and surgical ablation of atrial fibrillation. Developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology (ESC) and the European Cardiac Arrhythmia Society (ECAS); and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). Endorsed by the governing bodies of the American College of Cardiology Foundation, the American Heart Association, the European Cardiac Arrhythmia Society, the European Heart Rhythm Association, the Society of Thoracic Surgeons, the Asia Pacific Heart Rhythm Society, and the Heart Rhythm Society

    Heart Rhythm

    (2012)
  • D.J. Gladstone et al.

    Atrial fibrillation in patients with cryptogenic stroke

    N Engl J Med

    (2014)
  • T. Sanna et al.

    Cryptogenic stroke and underlying atrial fibrillation

    N Engl J Med

    (2014)
  • G.L. Botto et al.

    Presence and duration of atrial fibrillation detected by continuous monitoring: crucial implications for the risk of thromboembolic events

    J Cardiovasc Electrophysiol

    (2009)
  • G. Boriani et al.

    Improving stroke risk stratification using the CHADS2 and CHA2DS2-VASc risk scores in patients with paroxysmal atrial fibrillation by continuous arrhythmia burden monitoring

    Stroke

    (2011)
  • P.A. Wolf et al.

    Epidemiologic assessment of chronic atrial fibrillation and risk of stroke: The Framingham study

    Neurology

    (1978)
  • Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillation. Analysis of pooled data from five randomized controlled trials

    Arch Intern Med

    (1994)
  • Predictors of thromboembolism in atrial fibrillation: I. Clinical features of patients at risk. The stroke prevention in atrial fibrillation investigators

    Ann Intern Med

    (1992)
  • B.F. Gage et al.

    Validation of clinical classification schemes for predicting stroke: results from the national registry of atrial fibrillation

    JAMA

    (2001)
  • G.Y. Lip et al.

    Identifying patients at high risk for stroke despite anticoagulation: a comparison of contemporary stroke risk stratification schemes in an anticoagulated atrial fibrillation cohort

    Stroke

    (2010)
  • A.J. Camm

    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)
  • A.J. Camm et al.

    2012 focused update of the ESC guidelines for the management of atrial fibrillation: an update of the 2010 ESC guidelines for the management of atrial fibrillation. Developed with the special contribution of the European Heart Rhythm Association

    Eur Heart J

    (2012)
  • Cited by (44)

    • Management of Atrial Fibrillation in 2021: An Updated Comparison of the Current CCS/CHRS, ESC, and AHA/ACC/HRS Guidelines

      2021, Canadian Journal of Cardiology
      Citation Excerpt :

      In 2014, the CCS and AHA/ACC/HRS refined the definition to AF occurring in the absence of “rheumatic mitral stenosis, mitral valve repair, mechanical, or bioprosthetic heart valve.” In 2015, the CCS removed mitral-valve repair or bioprosthetic heart valve from the definition, with the ESC following suit in 2016.10 In 2020, the CCS/CHRS removed reference to “rheumatic valvular disease,” instead defining nonprosthetic valvular AF solely based on the severity of mitral stenosis (“moderate to severe”), in line with the ESC and the 2019 AHA/ACC/HRS guidelines (Supplemental Tables S1 and S2).5

    • The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

      2020, Canadian Journal of Cardiology
      Citation Excerpt :

      The risk was further refined by the delineation of various baseline characteristics that might affect the risk of the stroke.169-173 The first widely adopted tool for stroke risk assessment was the Congestive Heart Failure, Hypertension, Age, Diabetes, Stroke/Transient Ischemic Attack (CHADS2) score, which assigns a single point for HF, hypertension, age 75 years or older, and diabetes, and 2 points for previous stroke/systemic embolism.26,172 Unfortunately, CHADS2 was unable to adequately differentiate very low risk individuals (ie, in whom OAC is associated with a greater risk than benefit) from those at low but still clinically important stroke risk.

    View all citing articles on Scopus

    The disclosure information of the authors and reviewers is available from the CCS on their guidelines library at www.ccs.ca.

    View full text