New Atrial Fibrillation Guidelines Boost Blood Thinner Candidates

Almost all women and seniors with atrial fibrillation (AF) should be receiving blood thinners, advises a new analysis of updated clinical practice guidelines.

According to an analysis from the Duke Clinical Research Institute, which was published today in JAMA Internal Medicine, the latest AF management guidelines from the American Heart Association (AHA), American College of Cardiology (ACC), and Heart Rhythm Society (HRS) have broadened the proportion of AF patients recommended for blood-thinning anticoagulant drug therapy from 72% to 91%.

Additionally, 77% of women with AF currently qualify for anticoagulant drugs, but under the 2014 AHA/ACC/HRS guidelines, almost all women with AF (98%) are candidates for the oral medications, which help prevent AF from causing blood clots, stroke, and other thrombotic complications.

Since the new guidelines also lowered the age at which AF patients are considered at risk for stroke, from 75 to 65 years, nearly 99% of AF patients aged >65 years should be recommended to receive blood thinners, compared with approximately 80% under previous criteria.

Altogether, “the full adoption of the guidelines could reclassify nearly 1 million people with [AF] who previously weren’t recommended for treatment with blood thinners,” said lead study author Emily O’Brien, PhD, in a press release.

The investigators drew these conclusions from a registry of 10,132 AF patients enrolled in a 176-site US prospective, observational registry study known as ORBIT.

Other findings from the registry study included a relationship between bridging therapy (using an overlap of injected anticoagulants with warfarin to avoid its initial prothrombotic effect) and higher rates of bleeding.

Approximately one-fourth of patients in the registry using anticoagulants received bridging therapy, mostly with low-molecular-weight heparin (73%). Patients receiving bridging therapy were nearly 4 times more likely to experience bleeding than those taking an anticoagulant alone (odds ratio: 3.84; P <.0001). Unsurprisingly, those receiving bridging therapy were also more likely to have experienced a prior cerebrovascular event (P = .0003) and have had a mechanical valve in place (P <.0001).

An important implication from the bridging therapy finding may be expanded use of novel oral anticoagulants (NOACs), which do not require bridging therapy. Considering that nearly 1 in 4 patients who receive bridging therapy experience bleeding, NOACs may help reduce the risk of bleeding among patients who are at high risk for vascular events due to AF.

References

1. Duke Medicine. Guidelines Suggest Blood Thinners For More Women, Seniors [press release]. Accessed March 2, 2015.

2. Steinberg BA, Peterson ED, Kim S, et al. Use and Outcomes Associated With Bridging During Anticoagulation Interruptions in Patients With Atrial Fibrillation: Findings From the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). Circulation. 2015;131(5):488-494.