What is the medical treatment for patients on Aspirin (Acetylsalicylic Acid) and Novel Oral Anticoagulant (NOAC) who develop Atrial Fibrillation?

From the Guidelines

For patients already on aspirin (ASA) and a non-vitamin K oral anticoagulant (NOAC) who develop atrial fibrillation, the recommended approach is to discontinue aspirin and continue the NOAC alone, unless there is a compelling indication for dual therapy such as recent coronary stenting. The NOAC (apixaban, rivaroxaban, dabigatran, or edoxaban) should be dosed according to atrial fibrillation guidelines, which may differ from doses used for other indications, as suggested by the 2021 ACC expert consensus decision pathway 1. For example, apixaban is typically given as 5mg twice daily (or 2.5mg twice daily in patients meeting dose-reduction criteria such as age ≥80, weight ≤60kg, or serum creatinine ≥1.5mg/dL).

Continuing both medications unnecessarily increases bleeding risk without providing additional stroke prevention benefit, as highlighted in the 2018 European Heart Rhythm Association practical guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation 1. If the patient has a recent coronary stent or acute coronary syndrome, limited duration dual therapy may be needed, typically for 1-6 months depending on bleeding and thrombotic risks, after which the aspirin should be discontinued, as recommended by the 2021 ACC expert consensus decision pathway 1.

Some key points to consider in the management of these patients include:

• The risk of bleeding with triple antithrombotic therapy can be as high as 2.2% at 1 month and 4% to 12% at 1 year 1
• The addition of single APT to an OAC increases the risk of bleeding 20% to 60% and the addition of DAPT to an OAC further increases the risk 2- to 3-fold 1
• Regular monitoring for bleeding complications is essential, and renal function should be checked periodically as NOAC dosing may need adjustment based on creatinine clearance 1
• The ultimate goal is to preserve antithrombotic efficacy while mitigating bleeding, as stated in the 2021 ACC expert consensus decision pathway 1.

This approach balances stroke prevention in atrial fibrillation while minimizing bleeding risk, and is supported by the most recent and highest quality evidence available 1.

From the FDA Drug Label

The safety and efficacy of apixaban tablets have not been studied in patients with prosthetic heart valves. The most common reason for treatment discontinuation in both studies was for bleeding-related adverse reactions; In ARISTOTLE, the mean duration of exposure was 89 weeks (>15,000 patient-years). The following clinically significant adverse reactions are discussed in greater detail in other sections of the prescribing information. • Increased risk of thrombotic events after premature discontinuation [see Warnings and Precautions (5.1)] • Bleeding [see Warnings and Precautions (5.2)]

The medical treatment for those on ASA and NOAC who then develop atrial fibrillation is not directly addressed in the provided drug label.

• The label discusses the safety and efficacy of apixaban in patients with nonvalvular atrial fibrillation, but it does not provide guidance on managing patients who develop atrial fibrillation while taking ASA and NOAC.
• The label highlights the importance of considering the potential benefit versus the risk in anticoagulated patients or in patients to be anticoagulated for thromboprophylaxis.
• It is essential to consult the prescribing information for ASA and NOAC and consider the individual patient's risk factors and medical history to determine the best course of treatment 2.

From the Research

Medical Treatment for Atrial Fibrillation in Patients on ASA and NOAC

• The treatment for atrial fibrillation in patients on aspirin (ASA) and novel oral anticoagulants (NOACs) involves the use of oral anticoagulants to prevent stroke and systemic embolism 3, 4.
• NOACs, such as apixaban, dabigatran, and rivaroxaban, are acceptable alternatives to vitamin K antagonists (VKAs) like warfarin in certain situations, including the prevention of stroke and systemic embolism in patients with atrial fibrillation 3.
• The use of NOACs in combination with ASA may increase the risk of bleeding, but does not appear to provide additional benefit for stroke prevention compared to anticoagulation alone 5.
• Apixaban, a direct inhibitor of Factor Xa, has been shown to be superior to warfarin in both primary efficacy and primary safety outcomes, with lower rates of strokes and systemic embolism and a reduced risk of major clinical bleeding 6.
• However, a retrospective study found a higher incidence of ischemic stroke in patients taking NOACs compared to those taking warfarin, suggesting that patients on warfarin may be more strongly anticoagulated 7.

Considerations for Patient Management

• Special attention should be given when using NOACs in certain patient populations, including those with renal insufficiency, those receiving additional antithrombotic therapy, and those with a high risk of gastrointestinal bleeding 3.
• The choice of anticoagulant therapy should be individualized based on patient characteristics, including the risk of stroke and bleeding, and the presence of other medical conditions 4.
• Further research is needed to compare the efficacy and safety of different NOACs and to determine the optimal treatment strategy for patients with atrial fibrillation on ASA and NOACs 6.