Oral anticoagulation not efficient in sufferers with atrial high-rate episodes: Study

According to a examine offered in a Hot Line session at ESC Congress 2023, blood thinners (anticoagulants) trigger bleeding with out stopping stroke in people with atrial excessive charge episodes (AHRE), however with out electrocardiogram (ECG)-diagnosed atrial fibrillation.

The findings of the examine have been printed within the New England Journal of Medicine.

Anticoagulants work to stop strokes in individuals with atrial fibrillation, however they’re ineffective in individuals with out it, comparable to individuals with coronary heart failure. Atrial high-rate episodes (AHRE) are temporary and unusual atrial arrhythmias that resemble atrial fibrillation and are picked up by pacemakers, defibrillators, and loop recorders which are implanted within the physique. 10% to 30% of people with implanted units have AHRE.2 Even whereas individuals with AHRE have the next danger of stroke, this danger remains to be decrease than that of individuals with atrial fibrillation. In people with atrial fibrillation and elevated stroke danger, ESC suggestions advise oral anticoagulation to keep away from stroke, and so they advocate personalised selections in sufferers with AHRE however no ECG proof of atrial fibrillation.

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NOAH-AFNET 6 was the primary trial to research the efficacy and security of oral anticoagulation in sufferers with AHRE, however with out ECG-documented atrial fibrillation. The randomised, double-blind, double-dummy trial in contrast the anticoagulant edoxaban to placebo in sufferers ≥65 years with AHRE episodes ≥6 minutes detected by implantable units, and with at the least one further stroke danger issue (coronary heart failure, hypertension, diabetes, prior stroke or transient ischaemic assault, vascular illness, or age ≥75 years). This affected person inhabitants was outdoors the accepted indication of edoxaban.

In 206 websites throughout 18 European international locations, sufferers have been randomly allotted in a 1:1 vogue to anticoagulation or no anticoagulation. Anticoagulation consisted of edoxaban within the dose accepted for stroke prevention in atrial fibrillation (60 mg as soon as every day, lowered to 30 mg as soon as every day in keeping with accepted dose discount standards for stroke prevention in atrial fibrillation). No anticoagulation consisted of placebo containing no energetic compound or aspirin 100 mg as soon as every day in sufferers with a sign for antiplatelet remedy. The main consequence was a composite of stroke, systemic embolism, or cardiovascular dying. The security consequence was a composite of main bleeding and all-cause dying. All sufferers have been adopted till the tip of the trial.

The main, modified intention-to-treat evaluation inhabitants consisted of two,536 sufferers who acquired at the least one dose of examine drug. Patients have been aged with a number of stroke danger components: the imply age was 78 years, 37% have been ladies and the median CHA2DS2-VASc rating was 4.5 The median AHRE period at baseline was 2.8 hours with out an higher restrict, and 97% of AHRE confirmed atrial charges >200 beats per minute, clearly resembling atrial fibrillation.

The trial was stopped early as a consequence of security alerts and a development in the direction of futility for efficacy after enrolment of all deliberate sufferers. The main efficacy consequence occurred in 83 sufferers within the anticoagulation group (3.2%/yr) and in 101 sufferers within the no anticoagulation group (4.0%/yr), for a hazard ratio (HR) of 0.81 (95% confidence interval [CI] 0.6-1.1]; p=0.15). The stroke charge was low in each randomised teams (with out anticoagulation 1.1%/yr, with anticoagulation 0.9%/yr). The main security consequence occurred in 149 sufferers within the anticoagulation group (5.9%/yr) and in 114 sufferers within the no anticoagulation group (4.5%/yr), for a HR of 1.3 (95% CI 1.0-1.7; p=0.03). The distinction in security outcomes was pushed by an anticipated enhance in main bleeding in sufferers receiving anticoagulation (HR 2.10; 95% CI 1.30-3.38; p=0.002). ECG-diagnosed atrial fibrillation developed in 462/2536 sufferers (18%; 8.7%/yr).

Principal investigator Paulus Kirchhof of the University Heart & Vascular Center Hamburg, Germany stated: “The NOAH-AFNET 6 trial found that oral anticoagulation in patients with AHRE increases bleeding without reducing a composite outcome of stroke, systemic embolism, or cardiovascular death. The increased bleeding on anticoagulation therapy was expected. The low stroke rate with and without anticoagulation was unexpected. The results of NOAH-AFNET 6 clearly suggest to demand ECG documentation of atrial fibrillation prior to initiation of oral anticoagulation. Further research is needed to better understand the stroke risk in patients with very rare and short atrial arrhythmias.”

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