What are the Dual Anti-Platelet Therapy (DAPT) duration options, including medications and dosages, for patients with Non-ST-Elevation Myocardial Infarction (NSEMi) managed medically, with stenting, or with Coronary Artery Bypass Grafting (CABG), and how does the treatment plan change for patients with high bleeding risk?

DAPT Duration After NSTEMI: Medical Management, PCI, and CABG

For NSTEMI patients, regardless of management strategy (medical therapy, PCI, or CABG), the default DAPT duration is 12 months, with aspirin 75-100 mg daily plus a P2Y12 inhibitor (ticagrelor or prasugrel preferred over clopidogrel), shortened to 6 months in high bleeding risk patients or extended beyond 12 months in those who tolerate DAPT without bleeding complications. 1

Medication Regimens and Dosages

Aspirin Component

• Standard dose: 81 mg daily (range 75-100 mg) 1
• Continue indefinitely after P2Y12 inhibitor discontinuation 2

P2Y12 Inhibitor Selection for ACS/NSTEMI

Preferred agents (Class I recommendation): 1

• Ticagrelor: 180 mg loading dose, then 90 mg twice daily
• Prasugrel: 60 mg loading dose, then 10 mg daily 3
  • Reduce to 5 mg daily if body weight <60 kg 3
  • Contraindicated in patients with prior stroke/TIA 3
  • Generally not recommended in patients ≥75 years except high-risk situations (diabetes, prior MI) 3

Alternative agent:

• Clopidogrel: 300-600 mg loading dose, then 75 mg daily 1
• Use when ticagrelor/prasugrel contraindicated or in patients requiring oral anticoagulation 1

DAPT Duration by Management Strategy

NSTEMI Managed Medically (No Revascularization)

• Standard duration: 12 months minimum 1
• P2Y12 inhibitor choice: Ticagrelor preferred over clopidogrel (Class IIa) 1
• Extended DAPT: May continue beyond 12 months if tolerated without bleeding and not at high bleeding risk 1

NSTEMI with PCI/Stenting

• Standard duration: 12 months (Class I) 1
• Applies to both BMS and DES - stent type should not dictate duration 1
• High bleeding risk patients: 6 months may be reasonable 1
• Extended DAPT: Beyond 12 months may be considered in patients who tolerate DAPT without bleeding complications 1

NSTEMI with CABG

• Resume P2Y12 inhibitor postoperatively to complete 12 months total DAPT duration from ACS event (Class I) 1
• Restart as soon as safely possible after surgery 1

Abbreviated DAPT for High Bleeding Risk Patients

High bleeding risk patients should receive 6 months of DAPT after ACS, with consideration for even shorter durations (1-3 months) in extreme cases. 1

Shortened Duration Evidence

• 6 months: Recommended for high bleeding risk ACS patients 1
• 1-3 months: Recent evidence supports abbreviated DAPT in high bleeding risk patients undergoing PCI, showing reduced bleeding without increased ischemic events 4, 5
• Shortened DAPT reduces major bleeding (RR 0.66) and clinically-relevant bleeding (RR 0.60) without increasing MACE, MI, or stent thrombosis 4, 5

Bleeding Mitigation Strategies

• Use low-dose aspirin (75-100 mg) 1
• Consider reduced P2Y12 inhibitor dose when appropriate (prasugrel 5 mg if <60 kg) 3
• Routine PPI use in all patients on DAPT (Class I, ESC) 1
• Radial artery access for procedures 1
• Modify correctable bleeding risk factors 1

Bleeding Risk Stratification Tools

PRECISE-DAPT Score (Recommended by ESC)

The PRECISE-DAPT score is recommended for bleeding risk assessment to guide DAPT duration decisions. 1

Components include:

• Age
• Creatinine clearance
• Hemoglobin
• White blood cell count
• Prior bleeding

Interpretation:

• Score ≥25: High bleeding risk → consider shorter DAPT
• Score <25: Lower bleeding risk → standard or extended DAPT may be appropriate

DAPT Score (Recommended by ACC/AHA)

The DAPT score assesses benefit/risk ratio for prolonged DAPT beyond 12 months. 1

High score (≥2): Favorable benefit/risk for extended DAPT 1 Low score (<2): Unfavorable benefit/risk for extended DAPT 1

Clinical High Bleeding Risk Criteria

Patients are considered high bleeding risk if they have: 1

• Prior bleeding on DAPT
• Coagulopathy
• Oral anticoagulant use (2-3 fold increased bleeding risk) 1
• Body weight <60 kg 3
• Age ≥75 years 3
• Chronic NSAID use 3
• Planned major surgery (especially intracranial) 1
• Significant overt bleeding during DAPT 1

Critical Pitfalls to Avoid

• Never discontinue both antiplatelet agents simultaneously - transition to aspirin monotherapy after P2Y12 inhibitor completion 2
• Do not use prasugrel in patients with prior stroke/TIA - this is an absolute contraindication 3
• Avoid premature DAPT discontinuation in first 6 months - substantially increases risk of stent thrombosis, MI, and death 3
• Do not extend DAPT beyond 12 months without formal bleeding risk assessment - increases bleeding risk approximately 1% absolute without proportional ischemic benefit in unselected patients 1
• For patients requiring oral anticoagulation, limit triple therapy to maximum 6 months (preferably 1 month), then transition to dual therapy with OAC plus single antiplatelet agent 1
• Do not use ticagrelor or prasugrel with oral anticoagulation - clopidogrel is the only recommended P2Y12 inhibitor in triple therapy 1