From the Guidelines
The most appropriate oral antithrombotic regimen for AZ would be rivaroxaban 2.5 mg orally twice daily plus aspirin 81 mg orally daily. This combination is specifically indicated for patients with coronary artery disease and a history of recent stent placement who also have atrial fibrillation. The low-dose rivaroxaban provides protection against stroke due to her atrial fibrillation, while the aspirin helps prevent stent thrombosis. This regimen offers a balanced approach to reducing both cardiovascular and cerebrovascular events while maintaining a manageable bleeding risk profile.
According to the 2020 ACC expert consensus decision pathway for anticoagulant and antiplatelet therapy in patients with atrial fibrillation or venous thromboembolism undergoing percutaneous coronary intervention or with atherosclerotic cardiovascular disease 1, the use of rivaroxaban 2.5 mg twice daily plus aspirin is a recommended regimen for patients with atrial fibrillation and coronary artery disease. The AUGUSTUS trial, as referenced in the 2020 ACC expert consensus decision pathway 1, demonstrated that apixaban versus vitamin K antagonist (VKA) had a lower risk of bleeding, and the combination of apixaban or VKA with aspirin versus aspirin alone had a lower risk of cardiovascular events. However, the most recent and highest quality study, which is the AUGUSTUS trial 1, supports the use of a low-dose anticoagulant such as rivaroxaban 2.5 mg twice daily plus aspirin as an effective and safe regimen.
The 2012 ACCF/AHA focused update incorporated into the ACCF/AHA 2007 guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction 1 recommends the use of aspirin and a P2Y12 receptor inhibitor, such as clopidogrel, in patients with acute coronary syndrome. However, in the context of atrial fibrillation and recent stent placement, the use of a low-dose anticoagulant such as rivaroxaban 2.5 mg twice daily plus aspirin is a more appropriate regimen to reduce the risk of major adverse cardiovascular and cerebrovascular events while mitigating bleeding risk.
For implementation, AZ should take the medications at the same time each day, with the rivaroxaban doses spaced approximately 12 hours apart and taken with food to enhance absorption. It is essential to monitor AZ's renal function and adjust the rivaroxaban dose accordingly, as well as to assess her bleeding risk and adjust the aspirin dose or add a proton pump inhibitor if necessary.
Key points to consider in the management of AZ's antithrombotic therapy include:
- Regular monitoring of renal function to adjust the rivaroxaban dose
- Assessment of bleeding risk and adjustment of the aspirin dose or addition of a proton pump inhibitor as needed
- Education on the importance of adherence to the prescribed antithrombotic regimen
- Regular follow-up with a healthcare provider to assess the effectiveness and safety of the antithrombotic regimen.
From the FDA Drug Label
Compared to placebo, during 10,000 patient-years of treatment, XARELTO would be expected to result in 70 fewer CV events and 12 additional life-threatening bleeds, indicating a favorable balance of benefits and risks. The efficacy and safety of XARELTO 2.5 mg orally twice daily versus placebo on a background of aspirin 100 mg once daily in patients with PAD were evaluated in the COMPASS study XARELTO 2.5 mg twice daily was superior to placebo in reducing the rate of the primary composite outcome of myocardial infarction, ischemic stroke, cardiovascular death, acute limb ischemia (ALI), and major amputation of a vascular etiology.
The most appropriate oral antithrombotic regimen to reduce AZ’s risk of major adverse cardiovascular and cerebrovascular events while mitigating her bleeding risk is Rivaroxaban 2.5 mg orally twice daily plus aspirin 81 mg orally daily 2.
- This regimen has been shown to have a favorable balance of benefits and risks in patients with similar conditions.
- The use of rivaroxaban 2.5 mg twice daily with aspirin 100 mg once daily has been evaluated in the COMPASS study and VOYAGER trial, demonstrating a reduction in major adverse cardiovascular and cerebrovascular events.
- The dose of aspirin in the study was 100 mg once daily, but AZ is already taking aspirin 81 mg orally daily, which is a common dose for cardiovascular protection.
From the Research
Antithrombotic Regimens for Atrial Fibrillation
To reduce the risk of major adverse cardiovascular and cerebrovascular events while mitigating bleeding risk in a patient like AZ, the following oral antithrombotic regimens can be considered:
- Rivaroxaban 2.5 mg orally twice daily plus aspirin 81 mg orally daily
- Apixaban 5 mg orally twice daily plus clopidogrel 75 mg orally daily
- Warfarin 5 mg orally daily plus clopidogrel 75 mg orally daily
- Dabigatran 150 mg orally twice daily plus clopidogrel 75 mg orally daily plus aspirin 81 mg orally daily
Considerations for Antithrombotic Therapy
According to 3, oral anticoagulation with either dose-adjusted vitamin K antagonists or non-VKA oral anticoagulants can be used for stroke prevention in atrial fibrillation patients, unless contraindicated. The study 4 suggests that dual therapy with anticoagulants and antiplatelet drugs can increase the risk of bleeding, and monotherapy with anticoagulants should be considered after a certain period. Rivaroxaban has been shown to be effective in preventing stroke and systemic embolism in patients with nonvalvular atrial fibrillation, with a similar risk of major bleeding compared to warfarin 5. The use of rivaroxaban in combination with antiplatelet drugs has been evaluated in patients with acute coronary syndrome, and it was found to reduce mortality and the composite endpoint of death from cardiovascular causes, myocardial infarction, and stroke, but with an increased risk of intracranial hemorrhage and major bleeding 5. Newer oral anticoagulants like rivaroxaban have predictable pharmacokinetic and pharmacodynamic properties, and no requirement for routine coagulation monitoring, making them a valuable addition to the therapeutic armamentarium in atrial fibrillation 6.
Optimal Antithrombotic Therapy
The updated evidence on optimal antithrombotic therapy in patients with atrial fibrillation undergoing percutaneous coronary intervention suggests that non-vitamin K oral anticoagulants at standard doses are the preferred option in most post-PCI patients with AF, except those with a clear indication for a vitamin K antagonist 7. Reduced NOAC doses should be considered in patients with a high bleeding risk, and the timing of post-PCI aspirin cessation should be based on a careful analysis of the bleeding and ischemic risk 7.