Most Subclinical AF Patients Better Off Without Anticoagulants

The growing number of people walking around with cardiac monitoring devices will undoubtedly lead to far more subclinical AFib detections, but the NOAH-AFNET 6 trial provided some much needed reassurance that many of these patients would be better off without anticoagulants.

NOAH-AFNET 6 specifically evaluated patients with implantable device-detected atrial high-rate episodes (AHREs), who often don’t even notice these episodes, and can be treated with anticoagulants that were historically reserved for patients with ECG-diagnosed AFib.

The researchers randomized 2,536 older patients who had experienced AHREs (all ≥65yrs; 65% ≥75yrs) to take either edoxaban or a placebo, measuring the  anticoagulant’s efficacy (composite of: CV death, stroke, or systemic embolism) and safety (all cause mortality or major bleeding).

  • The edoxaban group had fewer efficacy events: 83 vs. 101 (3.2% vs. 4% per patient year)
  • But also significantly more safety outcomes: 149 vs. 114 (5.9% vs. 4.5% patient year)
  • And the two groups had similar rates of stroke: 0.9% vs. 1.0%

The trial was terminated early at a median 21 months (vs. goal of 220 primary events) after safety monitors noted the high rate of bleeding in the edoxaban group, and edoxaban’s apparent “futility” as an AHRE treatment.

This bad news for edoxaban supporters was celebrated as good news for patient care, including by two cardiologists with the largest platforms around:

  • Venk Murthy, MD expressed appreciation that this trial was done, but a lack of surprise about the result, given AHRE patients’ relatively low risks and considering that “anticoagulants are among the most dangerous of the widely prescribed meds.” Murthy also warned of how the trend towards Apple watch-based AFib monitoring will detect far more low-risk AFib patients who could be similarly harmed by unnecessary anticoagulant use.
  • John Mandrola, MD praised NOAH AFNET 6’s scientific fundamentals: it was well-conducted, addressed a common problem, delivered actional clinical results, and advanced our overall knowledge of AF. Although other forthcoming research will confirm whether this is truly “practice changing,” the study effectively shifted Mandrola’s approach towards holding off on anticoagulants with most of these patients.

The Takeaway

The growing number of patients who have been identified with AHRE or subclinical AF has placed new pressures on cardiologists who have to decide whether to solve for stroke risks (with anticoagulants) or bleeding risks (by withholding anticoagulants). The NOAH-AFNET trial added much needed data to support these decisions, clarifying that many of these patients are better off without anticoagulants.

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