What does Dual Antiplatelet Therapy (DAPT) entail?

Dual Antiplatelet Therapy (DAPT): Components and Clinical Application

Dual antiplatelet therapy (DAPT) consists of aspirin plus a P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel) and is essential for preventing thrombotic complications in patients with coronary artery disease, particularly after stent implantation. 1

Components of DAPT

Aspirin

• Low-dose aspirin (75-100 mg daily) is the foundation of DAPT
• Works by inhibiting cyclooxygenase 1-derived thromboxane A2
• Should be continued long-term in most cases

P2Y12 Inhibitors

1. Clopidogrel

   • Standard dosing: 600 mg loading dose, 75 mg daily maintenance
   • Default P2Y12 inhibitor for stable CAD patients undergoing PCI
   • Recommended for patients with indication for oral anticoagulation
   • Takes 5-7 days for platelet function to recover after discontinuation
   • Irreversibly binds to platelets for their lifespan (7-10 days) 2

2. Ticagrelor

   • Standard dosing: 180 mg loading dose, 90 mg twice daily maintenance
   • First-line therapy for ACS patients regardless of initial treatment strategy
   • More potent platelet inhibition than clopidogrel
   • Takes 3-5 days for platelet function to recover after discontinuation
   • Not recommended in patients requiring oral anticoagulation 1, 3

3. Prasugrel

   • Standard dosing: 60 mg loading dose, 10 mg daily maintenance
   • Recommended for P2Y12 inhibitor-naïve ACS patients undergoing PCI
   • Contraindicated in patients with prior intracranial bleeding
   • Takes 7-10 days for platelet function to recover after discontinuation
   • Not recommended in patients requiring oral anticoagulation 1, 4, 3

Duration of DAPT Based on Clinical Scenario

Stable Coronary Artery Disease with PCI

• Standard duration: 1-6 months depending on bleeding risk
• Longer duration may be considered if ischemic risk prevails over bleeding risk 1

Acute Coronary Syndrome (ACS)

• Standard duration: 12 months regardless of revascularization strategy
• 6-month therapy for high bleeding risk patients

• 12-month therapy may be considered in patients who tolerate DAPT without bleeding 1

Patients Requiring Oral Anticoagulation

• Triple therapy (DAPT + OAC) increases bleeding risk 2-3 fold
• Limit triple therapy to maximum 6 months or omit after hospital discharge
• Use clopidogrel as P2Y12 inhibitor (ticagrelor or prasugrel not recommended) 1

P2Y12 Inhibitor Selection Algorithm

1. For Stable CAD with PCI:

   • Clopidogrel is the default P2Y12 inhibitor

2. For ACS patients:

   • First choice: Ticagrelor or prasugrel
   • Use clopidogrel only if ticagrelor/prasugrel are contraindicated (prior intracranial bleeding, need for OAC)

3. For patients with oral anticoagulation:

   • Clopidogrel is the only recommended P2Y12 inhibitor

Perioperative Management of DAPT

• For elective surgery requiring P2Y12 inhibitor discontinuation:

  • Consider surgery after at least 1 month post-stenting
  • Stop clopidogrel 5-7 days before surgery
  • Stop ticagrelor ≥5 days before surgery
  • Stop prasugrel ≥7 days before surgery
  • Maintain aspirin throughout perioperative period if possible 1, 3

• For urgent surgery within 1 month of stenting:

  • Consider bridging with cangrelor, tirofiban, or eptifibatide if both antiplatelet agents must be discontinued 1

Strategies to Minimize Bleeding Risk

• Use radial access for coronary procedures
• Prescribe low-dose aspirin (75-100 mg)
• Consider appropriate P2Y12 inhibitor dosing
• Routinely use proton pump inhibitors 1, 5

Special Considerations

• Similar DAPT recommendations for both men and women
• Similar recommendations for patients with and without diabetes
• Patients with prior stent thrombosis should receive prolonged DAPT
• Prolonged DAPT may benefit patients with peripheral artery disease or who have undergone complex PCI 1

Common Pitfalls and Caveats

1. Stent selection and DAPT duration: Newer-generation drug-eluting stents (DES) no longer require longer DAPT compared to bare-metal stents. DAPT duration should be based on bleeding vs. ischemic risk assessment, not stent type 1

2. Premature DAPT discontinuation: Stopping DAPT prematurely, especially within first month after PCI, significantly increases risk of stent thrombosis and mortality 2

3. Bleeding management: If bleeding occurs while on DAPT, reassess type, dose, and duration. Only stop both agents in life-threatening bleeding when the source cannot be treated 1

4. Drug interactions: Consider potential interactions when selecting P2Y12 inhibitors, especially with oral anticoagulants 5

DAPT remains a cornerstone therapy for preventing thrombotic complications in coronary artery disease, but requires careful consideration of individual patient factors to balance ischemic and bleeding risks.