Should a DOAC be used alone or with aspirin for stroke prevention in an elderly patient with a history of stroke due to atrial fibrillation?

DOAC Alone—Do Not Add Aspirin

For an elderly patient with atrial fibrillation and prior stroke, use a DOAC as monotherapy without adding aspirin. Adding aspirin to anticoagulation provides no additional stroke protection but doubles the bleeding risk, which is particularly dangerous in elderly patients who already face twice the bleeding risk of younger patients 1, 2, 3.

Why DOAC Monotherapy Is Superior

The evidence is unequivocal: Combining antiplatelet agents with anticoagulants increases bleeding events without demonstrable benefit in preventing stroke or death 1.

• The 2024 ESC Guidelines explicitly state that antiplatelet drugs should not be used for stroke prevention in AF and can lead to potential harm, especially among elderly patients 1.
• Adding antiplatelet treatment to anticoagulation is not recommended (Class III recommendation) for preventing recurrent embolic stroke in AF patients 1.
• Oral anticoagulation alone reduces stroke risk by 62% in AF patients, while aspirin provides only 22% risk reduction 2.

The Bleeding Risk Reality

Elderly patients face substantially elevated bleeding risk that is further amplified by combination therapy:

• Patients ≥75 years have approximately twice the risk of serious bleeding complications during anticoagulation compared to younger patients 2, 4.
• The combination of oral anticoagulation with aspirin doubles bleeding risk without providing additional stroke benefit 3.
• Bleeding events are more common when antithrombotic agents are combined, with no clear benefit observed in terms of prevention of stroke or death 1.

When Combination Therapy Is Appropriate (The Only Exception)

Antiplatelet agents should only be combined with DOACs in selected patients with acute vascular disease (e.g., acute coronary syndromes or recent stenting), and even then, only for a limited duration 1.

• For stable coronary artery disease (no acute coronary syndrome within the previous year), use anticoagulation alone rather than combination therapy 1.
• The COMPASS trial's low-dose rivaroxaban plus aspirin combination cannot be generalized to AF patients because those with an indication for full-dose anticoagulants were excluded 1.

Practical Management Algorithm

Follow this approach for your elderly stroke patient:

1. Verify appropriate DOAC dosing based on age, weight, and renal function 2, 4.
2. Discontinue aspirin unless there is a compelling acute vascular indication (recent ACS or stenting within past year) 1, 3.
3. Optimize modifiable bleeding risk factors using the HAS-BLED score, which includes hypertension, abnormal renal function, and elderly age 2, 4.
4. Target blood pressure <140/90 mmHg (ideally <130/80 mmHg if tolerated) to reduce both stroke and intracranial hemorrhage risk 2, 3.
5. Assess renal function at least annually, or 2-3 times yearly if creatinine clearance is 30-49 mL/min 2.

Critical Pitfalls to Avoid

Never use antiplatelet therapy alone when oral anticoagulation is indicated for atrial fibrillation 2.

• A HAS-BLED score ≥3 indicates high bleeding risk but should NOT be used to withhold anticoagulation; instead, it mandates more frequent monitoring and aggressive management of modifiable risk factors 2, 4.
• Elderly age alone is NOT a contraindication to anticoagulation—the stroke prevention benefit exceeds bleeding risk in the vast majority of cases 2, 4.
• Avoid concomitant NSAIDs completely, as these medications increase bleeding risk without additional stroke benefit 3, 4.

The Evidence Hierarchy

The 2024 ESC Guidelines (the most recent and highest-quality evidence) provide the clearest directive: antiplatelet drugs are not an alternative to oral anticoagulation and should not be used for stroke prevention in AF 1. This represents a Class III recommendation (harm), meaning the intervention should not be performed as it is not helpful and may be harmful 1.