Oral Anticoagulation in patients with non-valvular atrial fibrillation and a CHA2DS2-VASc score of 1

Current ESC guidelines recommend the initiation of oral anticoagulation (OAC); preferably non-vitamin K antagonist oral anticoagulants (NOACs) or vitamin K antagonists (VKAs) in atrial fibrillation (AF) patients with a CHA2DS2-VASc score ≥2 for lowering the individual stroke risk, while an OAC approach in individuals with a CHA2DS2-VASc score of 0 is not recommended.1 However, OAC in patients presenting with a CHA2DS2-VASc of 1 (CHA2DS2-VASc of 2 in women) remains a challenging approach in clinical practice and physicians need to carefully balance the individual benefit of reducing thromboembolic risk with OAC against the potential harm due to an increase in bleeding risk in this patient population. In the current opinion statement of the ESC Working Group of Cardiovascular Pharmacotherapy and the ESC Council on Stroke, the authors summarize the currently available evidence in this field.2 Most importantly, an easily applicable approach for a personalized refinement of the individual thromboembolic risk in patients with AF and a CHA2DS2-VASc score of 1 that guides clinicians through the question whether to anticoagulate or not, is provided. The assessment of patients’ individual risk for major bleeding is a key prerequisite for initiation of OAC. The HAS-BLED score mirrors a widely validated and accepted tool for this purpose. Based on the individual bleeding risk of 0.59–1.51% per year in HAS-BLED score of 1 and an annual thromboembolic risk of 0.6–1.3% in CHA2DS2-VASc of 1, physicians are not able to draw a definite conclusion concerning the net benefit of OAC in relevant patients. Therefore, a general recommendation for OAC therapy in these individuals is not justified and patients that benefit from OAC need to be identified using a personalized approach. In contrast, patients with a HAS-BLED score of 2 (or even higher) an OAC should not be initiated in intermediate thromboembolic risk patients based on an annual bleeding rate of 1.88–3.20% per year.3–6 Considering the predictive potential for thromboembolic events in characteristics used for the calculation of the CHA2DS2-VASc score, age (>65 years) and diabetes mellitus Type II may be the most important individual risk factors.7 Moreover, the authors conclude that the burden of atrial arrythmia—such as AF (not atrial flutter) and permanent/persistent (not paroxysmal) of the arrythmia needs to be taken into account.8–11 Further patient characteristics that proved to be associated with an increased thromboembolic risk were outlined as obesity (body mass index ≥30) and impaired renal function—evidenced by proteinuria (>150 mg/24 h or equivalent) or estimated glomerular filtration rate of <45 mL/h. Additionally, imaging values, such as enlarged left atrial volume (≥73 mL) or diameter (≥4.7 cm) or left atrial appendage emptying velocity (<20 cm/s) seem reasonable and easily assessed imaging markers for risk stratification.12–14 Of utmost importance, routinely available biomarkers such as cardiac troponin (high-sensitivity Troponin T or I) and Nt-proBNP (1400 ng/L) may provide additional prognostic information to enhance risk estimation and decision making for OAC particularly in intermediate-risk individuals.1 Of note, despite an individualized weighing of risk and additional prognostic values, the patients’ preferences are crucial for a decision on OAC in order to ensure compliance, which strongly influences outcomes. The ESC Working Group of Cardiovascular Pharmacotherapy and the ESC Council on Stroke conclude that decisions should be based on the individual balance between thromboembolic and bleeding risk. The major therapeutic preference should be, on doing no harm, rather than avoiding stroke. In this regard, several values and strategies for risk stratification were provided for clinicians to determine the individual thromboembolic risk in patients presenting with a CHA2DS2-VASc score of 1. If the decision for OAC initiation in AF patients presenting with a CHA2DS2-VASc score of 1 has been made, NOACs with a superior net-clinical benefit should be preferred over VKAs. There is no evidence that patients with AF presenting with a CHA2DS2-VASc score of 1 benefit from acetylsalicylic acid (ASA) therapy—therefore, ASA for stroke prevention should not be considered in this intermediate-risk patient population. Of utmost importance, an easily applicable tool—including patient characteristics that favour OAC and a decision tree for the initiation of OAC—is now available to guide clinicians through the question whether to anticoagulate or not and to offer AF patients with a CHA2DS2-VASc score of 1 the currently most possible benefit (see Figure 1). Decision tree for oral anticoagulation in patients with atrial fibrillation and a CHA2DS2-VASc score of 1 and values for individual risk stratification. Values that favour oral anticoagulation and allow individual thromboembolic risk stratification in atrial fibrillation patients with a CHA2DS2-Vasc of 1. eGFR, estimated glomerular filtration rate; LA, left atrium; LAA, left atrial appendage; NOAC, non-vitamin K antagonist oral anticoagulant; Nt-proBNP, N-terminal pro-B-type natriuretic peptide; OAC, oral anticoagulation; VKA, vitamin K antagonist. Conflict of interest: S.W. reports personal fees from Bristol Myers Squibb, Boehringer Ingelheim, Pfizer, and Daiichi Sankyo, outside the submitted work. A.G.S. received speaker honoraria and/or consulting fee from Lilly, Novartis, AbbVie, Bayer, Roche, and Sanofi. W.D. reports grants and personal fees from Vifor; personal fees from Pfizer and Boehringer Ingelheim; personal fees and non-financial support from Sphingotec; grants from ZS Pharma; personal fees from Bayer and Medtronic, outside the submitted work. T.G. reports personal fees from Bayer, Daiichi Sankyo, Boehringer Ingelheim, Bristol Myers Squibb, and Pfizer, outside the submitted work. J.C.K. reports personal fees from Bayer UK, outside the submitted work. G.S. reports grants and personal fees from Vifor, Boehringer Ingelheim, and AstraZeneca; personal fees from Roche, outside the submitted work; C.T.-P. reports grants from Bayer, outside the submitted work. B.S.L. reports grants and personal fees from BMS; personal fees from Pfizer; grants from Boehringer Ingelheim, Daichi-Sankyo, and Bayer Healthcare, during the conduct of the study. D.A. reports personal fees from Boehringer Ingelheim; grants and personal fees from BMS/Pfizer, personal fees from MSD, personal fees from Bayer, AstraZeneca, and Sanofi; grants from Medtronic, outside the submitted work. S.A. reports personal fees from Boehringer Ingelheim, Pfizer, and AstraZeneca. A.N. reports personal fees from Bayer and BMS; grants and personal fees from Boehringer Ingelheim and Daiichi Sankyo; personal fees from Pfizer, outside the submitted work. And all other authors have no conflict of interest to declare. References are available as supplementary material at European Heart Journal online.