Does a patient with a history of cardiovascular disease, specifically coronary artery disease, need to continue taking aspirin and Effient (prasugrel) while on a heparin drip?

Dual Antiplatelet Therapy During Heparin Infusion

Yes, patients with coronary artery disease requiring dual antiplatelet therapy (DAPT) must continue both aspirin and Effient (prasugrel) even while on a heparin drip, as these medications target different mechanisms of thrombosis and are not interchangeable. 1, 2

Why All Three Agents Are Necessary

Different Mechanisms of Action

• Aspirin irreversibly inhibits platelet cyclooxygenase, preventing thromboxane A2 formation and providing baseline platelet inhibition 1
• Prasugrel (Effient) irreversibly blocks the P2Y12 receptor on platelets, providing more potent and consistent platelet inhibition than aspirin alone 1, 3
• Heparin works through an entirely different mechanism by enhancing antithrombin activity to prevent fibrin formation, but does not directly inhibit platelet aggregation 1

Clinical Evidence Supporting Continuation

• The ACC/AHA guidelines explicitly state that for ACS patients, aspirin should be continued during heparin therapy and a P2Y12 inhibitor (prasugrel, ticagrelor, or clopidogrel) should be administered for at least 12 months 1
• Heparin is typically discontinued after PCI or within 48 hours to 8 days depending on the formulation, while DAPT continues for a minimum of 12 months 1
• The combination of aspirin plus prasugrel reduces ischemic events by 19% compared to aspirin plus clopidogrel, demonstrating the critical importance of maintaining both antiplatelet agents 3

Specific Management Algorithm

For ACS Patients on Heparin Drip

1. Continue aspirin 81 mg daily (75-100 mg range acceptable) throughout hospitalization and indefinitely 1, 2
2. Continue prasugrel 10 mg daily (or 5 mg if patient weighs <60 kg) for at least 12 months from the index event 1
3. Maintain heparin infusion as clinically indicated, typically until PCI is performed or for 48 hours in medically managed patients 1
4. Discontinue heparin after PCI for uncomplicated cases, but continue DAPT 1

Critical Timing Considerations

• If the patient requires urgent CABG, prasugrel should be discontinued at least 7 days before surgery (not just stopped because they're on heparin) 1
• Heparin can be continued through CABG, while prasugrel must be held 1
• After CABG, prasugrel should be resumed as soon as safely possible to complete 12 months of DAPT 1

Important Safety Caveats

Bleeding Risk Management

• The combination of heparin plus DAPT does increase bleeding risk, but the benefit outweighs this risk in ACS patients 4
• Add a proton pump inhibitor (pantoprazole or rabeprazole preferred) to reduce GI bleeding risk when using triple antithrombotic therapy 1, 2
• Use radial rather than femoral access for any catheterization procedures to minimize bleeding complications 1, 2

Contraindications to Prasugrel

• Do not use prasugrel in patients with prior stroke or TIA (absolute contraindication) 1, 3
• Exercise caution in patients ≥75 years old due to increased bleeding risk, though may be reasonable in high-risk situations like diabetes or prior MI 1, 5
• Consider dose reduction to 5 mg daily in patients <60 kg 1

When to Reconsider the Regimen

• If major bleeding occurs while on heparin plus DAPT, the heparin should typically be discontinued first (as it's the temporary agent), while maintaining DAPT unless bleeding is life-threatening 1
• For patients requiring long-term oral anticoagulation (e.g., atrial fibrillation), switch from prasugrel to clopidogrel as the P2Y12 inhibitor component, as prasugrel with anticoagulation carries excessive bleeding risk 1, 6

Common Clinical Pitfall

The most dangerous error is assuming heparin "covers" antiplatelet therapy and stopping DAPT. Heparin prevents fibrin clot propagation but does not prevent platelet aggregation at the site of plaque rupture or stent thrombosis. Discontinuing DAPT in ACS patients, particularly those with recent stents, carries a hazard ratio of 161 for acute MI or death 1. The mechanisms are complementary, not redundant.