What is the optimal aspirin treatment regimen for a patient with coronary artery disease, stents, and normal heart function, and how should it be modified for a patient with mild impaired renal function (Glomerular Filtration Rate (GFR) of 66)?

Optimal Aspirin Regimen for Coronary Artery Disease with Stents and Mild Renal Impairment

For patients with coronary artery disease, stents, and normal heart function with mild renal impairment (GFR of 66), low-dose aspirin at 81 mg daily (range 75-100 mg) is the recommended maintenance regimen. 1

Aspirin Dosing Recommendations

• The optimal aspirin maintenance dose for patients with coronary artery disease and stents is 81 mg daily (range 75-100 mg), which provides effective platelet inhibition while minimizing bleeding risk 1
• After percutaneous coronary intervention (PCI), it is reasonable to use 81 mg of aspirin per day in preference to higher maintenance doses 1
• Lower daily doses of aspirin (75-100 mg) are associated with lower bleeding complications and comparable ischemic protection compared to higher doses 1
• The ADAPTABLE trial showed no significant differences in cardiovascular events or major bleeding between individuals assigned to 81 mg versus 325 mg of aspirin daily 1

Duration of Therapy

• Aspirin therapy should be continued indefinitely (lifelong) in all patients with coronary artery disease unless contraindicated 1
• For patients with stents, dual antiplatelet therapy (DAPT) consisting of aspirin plus a P2Y12 inhibitor (clopidogrel, prasugrel, or ticagrelor) is recommended for a specific duration depending on stent type and clinical scenario 1
• After the DAPT period, aspirin monotherapy should be continued indefinitely 1

Considerations for Mild Renal Impairment (GFR 66)

• Mild renal impairment (GFR 66) does not require modification of the aspirin dose 2
• Studies have shown that moderately impaired renal function is not associated with a reduced antiplatelet effect of aspirin 2
• No dose adjustment of aspirin is necessary based on a GFR of 66, as this level of renal impairment does not significantly impact aspirin's antiplatelet effects 2

Initial Loading Dose Considerations

• For acute coronary syndromes, an initial loading dose of aspirin between 162 and 325 mg is recommended 1
• After this initial loading dose, transition to the maintenance dose of 81 mg daily is appropriate 1

Dual Antiplatelet Therapy (DAPT) Considerations

• For patients with coronary stents, DAPT with aspirin plus a P2Y12 inhibitor (clopidogrel, prasugrel, or ticagrelor) is indicated 1
• When using prasugrel as part of DAPT, patients should also take aspirin (75-325 mg) daily 3
• The recommended maintenance dose of aspirin to be used with ticagrelor is specifically 81 mg daily 1

Common Pitfalls and Caveats

• Higher doses of aspirin (>100 mg daily) are associated with increased bleeding risk without additional reduction in thrombotic events 1, 4
• The CURE trial demonstrated a dose-dependent increase in bleeding with higher aspirin doses: 2.0% with <100 mg, 2.3% with 100-200 mg, and 4.0% with >200 mg per day 1
• Enteric-coated aspirin should be avoided initially in acute settings due to delayed and reduced absorption 1
• Platelet inhibition by aspirin may decline during the 24-hour dosing interval, but once-daily dosing remains the standard recommendation 5
• Proton pump inhibitors should be considered for patients at increased risk of gastrointestinal bleeding while on aspirin therapy 1

Algorithm for Aspirin Management in CAD with Stents and Mild Renal Impairment

1. Initiate with loading dose (162-325 mg) if acute presentation 1
2. Maintain on 81 mg daily (range 75-100 mg) indefinitely 1
3. Combine with appropriate P2Y12 inhibitor for the recommended DAPT duration based on stent type 1
4. Continue aspirin 81 mg daily indefinitely after completion of DAPT period 1
5. No dose adjustment needed for mild renal impairment (GFR 66) 2