Stroke Prevention in Nonvalvular Atrial Fibrillation

Alkhouli M, Noseworthy PA, Rihal CS, Holmes DR Jr.
Stroke Prevention in Nonvalvular Atrial Fibrillation: A Stakeholder Perspective. J Am Coll Cardiol 2018;71:2790-2801.

The following are key points to remember from this stakeholder perspective on stroke prevention and nonvalvular atrial fibrillation (AF):

  1. AF is the most common sustained cardiac arrhythmia, present in a projected >12 million Americans by 2030. Stroke is the most debilitating complication of AF, occurring in up to 125,000 Americans annually.
  2. The prevalence of AF among patients admitted with acute ischemic stroke has increased from 16% to 20% between 2003 and 2014. AF-related strokes are more disabling, more likely to recur, and are associated with a higher mortality than non-AF-associated strokes.
  3. Stroke prevention with oral anticoagulation remains a challenge, with fewer than 50% of high-risk patients receiving therapy in the US PINNACLE registry. Adherence to anticoagulation is also suboptimal, both with warfarin and the direct oral anticoagulants (DOACs).
  4. Available strategies to prevent stroke in AF include the use of warfarin, DOACs, antiplatelet therapy (e.g., aspirin or dual antiplatelet therapy), and left atrial appendage occlusion/excision (both percutaneous and surgical).
  5. Warfarin is a highly effective strategy for stroke prevention in AF, having been used for decades. It is low cost, readily available, and has an easy-to-administer antidote. However, it is cumbersome to monitor, has numerous drug-drug and drug-food interactions, and the quality of anticoagulation is generally suboptimal.
  6. In the past decade, DOACs have emerged as first-line therapy to prevent AF-related stroke for many patients because of their efficacy, ease of use, and low risk of bleeding complications. However, they can be expensive for many patients, and an antidote is not universally available.
  7. Antiplatelet therapy is generally less effective at stroke prevention in AF than anticoagulation, and is not recommended for most patients.
  8. Percutaneous left atrial appendage occlusion with the Watchman device has been shown to be noninferior to warfarin for the reduction of all-cause stroke or systemic embolism in a patient-level meta-analysis of two randomized trials. This device is FDA approved for patients at increased risk of stroke who have an appropriate rationale to seek a nonpharmacologic alternative to warfarin. Surveillance of outcomes has been mandated by the Centers for Medicare and Medicaid Services in order to receive reimbursement for placement of the Watchman device.
  9. Surgical ligation of the left atrial appendage is often performed in patients with AF at the time of cardiac surgery. However, several studies have found that this procedure is incomplete in up to 40% of patients, which is associated with left atrial appendage thrombus formation and stroke risk. This can be done either with a suture or with external clipping (e.g., with the AtriClip).
  10. The available data suggest a critical knowledge gap in patients’ perception of their stroke risk and the risk/benefit trade-off of various stroke prevention modalities. Decision aid tools have been shown to improve patients’ knowledge, engagement, and satisfaction. However, they are not always easy to use in clinical practice and often do not include the most contemporary treatment options.

Keywords: Anticoagulants, Arrhythmias, Cardiac, Aspirin, Atrial Appendage, Atrial Fibrillation, Brain Ischemia, Cardiac Surgical Procedures, Coronary Occlusion, Embolism, PINNACLE Registry, Platelet Aggregation Inhibitors, Secondary Prevention, Risk, Stroke, Thrombosis, Vascular Diseases, Warfarin

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