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Pointers for oral anticoagulants and antiplatelet therapy use in patients with atrial fibrillation: News from GARFIELD-AF

ESC Congress News 2018 - Munich, Germany

The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is the largest multinational prospective registry in AF. Late-breaking abstract presentations yesterday reported new studies from this registry looking at the comparative effectiveness of oral anticoagulants (OACs) and adverse outcomes following combination OACs plus antiplatelet therapy.

Atrial Fibrillation
Anticoagulants
Antiplatelet Drugs


Camm-John-2015.jpgProfessor John Camm (St George’s University of London, London, UK) reported results of a study comparing the use of OACs vs no OACs—and, within this, a comparison of non-vitamin K antagonist oral anticoagulants (NOACs) vs vitamin K antagonists (VKAs)—in patients with AF and a high risk of stroke (CHA2DS2-VASc score ≥2, including gender). “We know from clinical trials that OACs can prevent strokes and extend the lives of patients with AF, and guidelines recommend OACs for men and women with CHA2DS2-VASc scores of 1 and 2, respectively,(1)” begins Prof. Camm. “GARFIELD-AF gives us the opportunity to look at the effects of OACs, and to compare different types of agents, in the context of real-world, daily clinical practice.”

The analysis included patients who were receiving OACs with or without antiplatelet therapy and who were enrolled consecutively onto the registry between April 2013 and September 2016. “This is the time that NOACs became available in many countries,” observes Prof. Camm. A total of 20,564 patients receiving OACs (NOACs [n=10,380] and VKAs [n=10,184]) and 7,608 patients not receiving OACs were included and followed up for two years. Most of the patients not receiving OACs were on antiplatelet therapy (83.3%). “The 24-month survival rate was 91.8%,” reports Prof. Camm. “Slightly more deaths were non-cardiovascular vs cardiovascular related and the main known causes were congestive heart failure and cancer, at 12% each.”

There was a clear survival benefit for OAC use.

“Compared with no OAC use, OAC use was associated with reductions in all-cause mortality (hazard ratio [HR] 0.83; 95% confidence intervals [CI] 0.75–0.93; p=0.002) and stroke/systemic embolism (SE) (HR 0.79; 95% CI 0.64–0.97; p=0.028),” he says. “In terms of the type of OAC, NOACs were superior to VKAs for all-cause mortality (HR 0.81; 95% CI 0.71–0.92; p<0.001) but were not associated with significant reductions in stroke/SE. The survival benefits associated with OACs and NOACs persisted after adjustment for baseline variables.” As expected, the risk of major bleeding was significantly higher in the OAC vs the non-OAC group (HR 1.41; 95% CI 1.04–1.91; p=0.029). However, the risk was not significantly different between NOACs and VKAs.

Prof. Camm concludes that, “The results associated with OAC use in this real-world setting support observations from clinical trials and highlight the benefits of OACs for patients with AF in everyday clinical practice. GARFIELD-AF results confirm that oral anticoagulation in real-world experience reduces stroke and mortality, but trends to increase major bleeding. Stroke and major bleeding trend towards being less with NOACs compared with VKAs, but mortality is significantly reduced.”

Fox-Keith-2015.jpgThe results of a study evaluating the risks vs the benefits of combination OAC/antiplatelet therapy initiated at the time of AF diagnosis were reported by Professor Keith Fox (University of Edinburgh, Edinburgh, UK) (Abstract 5878). “OAC use is standard for AF patients at a high risk of stroke,” explains Prof. Fox, “but, because of the increased risk of bleeding, the addition of antiplatelet agents is generally recommended only when prevention of coronary or peripheral artery thrombosis is required, such as in patients having a myocardial infarction (MI) or those with peripheral artery disease (PAD). However, we don’t really have a clear idea of the level of risk vs benefit for this type of combination therapy in AF patients without a clear indication for it.”

A total of 25,815 newly diagnosed patients receiving OACs (OACs plus antiplatelet therapy [n=3,133] and OACs alone [n=22,682]) were included in the study. “While most patients receiving combination therapy had a higher prevalence of coronary artery disease (CAD), acute coronary syndrome and stroke,” says Prof. Fox, “1,743 patients had neither CAD nor PAD.”

Overall, the use of combination OAC/antiplatelet therapy was associated with an increased risk of major bleeding (HR 1.45; 95% CI 0.94–2.23) and all-cause mortality (HR 1.31; 95% CI 1.05–1.62) and no reduction in the risk of stroke (HR 1.60; 95% CI 1.08–2.35).

Prof. Fox reports that the risks of mortality, stroke and major bleeding were generally greater in patients treated with anticoagulation plus antiplatelet therapy, without CAD or PAD. “Even after excluding those with prior PAD or CAD, the HR for all-cause mortality with OAC plus antiplatelet therapy vs OAC alone was 1.48 among those without CAD/PAD and 1.31 for all patients,” he notes, “and hazard increases were also observed for stroke and major bleeding. The increased risk remained even after propensity score matching.”

Summing up, Prof. Fox says, “Patients receiving combined OAC/antiplatelet therapy at the time of AF diagnosis have a worse prognosis than those receiving OACs alone, and this appears to be particularly true for patients without a clear indication for antiplatelet therapy. The findings challenge the addition of antiplatelet therapy to full oral anticoagulation unless there is a good indication for using the combination.”

1. Kirchhof P, et al. Eur Heart J 2016;37:2893–2962.

24-month Nelson-Aalen-adjusted survival curves comparinga) OACs vs no OACs and b) NOACs vs VKAs

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Notes to editor

About the European Society of Cardiology

The European Society of Cardiology brings together healthcare professionals from more than 150 countries, working to advance cardiovascular medicine and help people lead longer, healthier lives.

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ESC Congress is the world’s largest and most influential cardiovascular event contributing to global awareness of the latest clinical trials and breakthrough discoveries. ESC Congress 2018 takes place 25 to 29 August at the Messe München in Munich, Germany. Explore the scientific programme