What is the evidence for adding antiplatelet(s) to a patient with a history of Transient Ischemic Attack (TIA) symptoms who is already on anticoagulation therapy with Eliquis (apixaban) or another anticoagulant for carotid artery stenosis?

From the Guidelines

The addition of antiplatelet therapy to anticoagulation in patients with TIA symptoms who are already on Eliquis (apixaban) or another anticoagulant and have carotid artery stenosis is generally not recommended due to significantly increased bleeding risk without clear additional benefit. For patients with carotid stenosis experiencing TIAs despite anticoagulation, the preferred approach is to optimize the current anticoagulation regimen or consider carotid revascularization (endarterectomy or stenting) rather than adding an antiplatelet agent. If antiplatelet therapy must be considered, it should be for the shortest duration possible, typically using low-dose aspirin (81mg daily) 1. The combination of anticoagulants and antiplatelets substantially increases major bleeding risk by 2-3 fold compared to anticoagulation alone. This risk-benefit assessment is particularly important since the anticoagulant is already providing significant protection against thromboembolism. In cases where both therapies seem necessary (such as recent carotid stenting in a patient requiring anticoagulation for atrial fibrillation), close monitoring for bleeding complications is essential, and the combination therapy should be limited to the shortest duration needed. The underlying mechanism for avoiding dual therapy relates to the redundant antithrombotic effects coupled with additive bleeding risks affecting different hemostatic pathways simultaneously.

Some key points to consider:

• The guidelines recommend antiplatelet agents rather than oral anticoagulation for patients with noncardioembolic ischemic stroke or TIA to reduce the risk of recurrent stroke and other cardiovascular events 1.
• The selection of an antiplatelet agent should be individualized based on patient risk factor profiles, tolerance, and other clinical characteristics 1.
• The addition of aspirin to clopidogrel increases the risk of hemorrhage and is not routinely recommended for ischemic stroke or TIA patients 1.
• For patients with carotid dissections, antithrombotic treatment for at least 3 to 6 months is reasonable, but the relative efficacy of antiplatelet therapy compared with anticoagulation is unknown 1.

Overall, the decision to add antiplatelet therapy to anticoagulation in patients with TIA symptoms and carotid artery stenosis should be made on a case-by-case basis, taking into account the individual patient's risk factors and clinical characteristics. However, in general, the risks of bleeding associated with dual therapy outweigh the potential benefits, and alternative strategies such as optimizing anticoagulation or considering carotid revascularization should be prioritized.

From the Research

Evidence for Adding Antiplatelet(s) to Anticoagulation Therapy

The evidence for adding antiplatelet(s) to a patient with a history of Transient Ischemic Attack (TIA) symptoms who is already on anticoagulation therapy with Eliquis (apixaban) or another anticoagulant for carotid artery stenosis is as follows:

• A study published in 2005 2 found that combination therapy with clopidogrel and aspirin is more effective than aspirin alone in reducing asymptomatic embolization in patients with recently symptomatic carotid stenosis.
• A review published in 2019 3 found that there is insufficient evidence to recommend routine aspirin-clopidogrel combination therapy to reduce the risk of recurrent clinical ischemic events in patients with symptomatic moderate-severe carotid stenosis.
• A study published in 2022 4 found that short-term preoperative anticoagulation in patients with acutely symptomatic carotid stenosis appears safe and effective compared to antiplatelet agents alone in the prevention of recurrent cerebral ischemic events while awaiting carotid endarterectomy.
• A review published in 2009 5 found that antiplatelet therapy and aggressive treatment of vascular risk factors are the mainstays of medical therapy for carotid artery stenosis.
• An update published in 2015 6 found that antiplatelet therapy should be considered in asymptomatic and symptomatic patients with carotid artery stenosis, and that perioperative antithrombotic therapy in patients undergoing carotid stenting should consist of a combination of aspirin plus clopidogrel.

Key Findings

• The use of dual antiplatelet therapy with clopidogrel and aspirin may be beneficial in reducing asymptomatic embolization in patients with symptomatic carotid stenosis 2.
• The addition of clopidogrel to aspirin may be considered on a case-by-case basis in patients undergoing carotid endarterectomy 6.
• Anticoagulation therapy may be safe and effective in preventing recurrent cerebral ischemic events in patients with acutely symptomatic carotid stenosis while awaiting carotid endarterectomy 4.
• The optimal antithrombotic regimen for patients with carotid artery stenosis is not well established, and further research is needed to determine the best approach 3, 5.