What is the recommended timeline for dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor, such as clopidogrel, prasugrel, or ticagrelor?

Guideline for Dual Antiplatelet Therapy Timeline

For acute coronary syndrome (ACS) patients, dual antiplatelet therapy (DAPT) with aspirin plus a P2Y12 inhibitor should be continued for 12 months, with ticagrelor as the preferred P2Y12 inhibitor over clopidogrel or prasugrel. 1, 2

Standard DAPT Duration by Clinical Scenario

Acute Coronary Syndrome with PCI (Stent Placement)

• Continue DAPT for at least 12 months after bare-metal stent (BMS) or drug-eluting stent (DES) implantation 1, 2
• This applies to both STEMI and NSTE-ACS patients undergoing percutaneous coronary intervention 1
• After CABG in ACS patients, resume P2Y12 inhibitor therapy postoperatively to complete the full 12-month course 1

Acute Coronary Syndrome with Medical Management Alone

• Continue DAPT for at least 12 months in patients managed without revascularization 1, 2
• Use either clopidogrel or ticagrelor (ticagrelor preferred for NSTE-ACS) 1

STEMI with Fibrinolytic Therapy

• Minimum 14 days of clopidogrel (strong evidence), ideally extended to 12 months 1
• Use clopidogrel 300 mg loading dose in patients <75 years, then 75 mg daily 1

Stable Coronary Artery Disease with Elective PCI

• Minimum 6 months of DAPT after drug-eluting stent implantation in stable ischemic heart disease 1
• This is a shorter duration than ACS patients due to lower thrombotic risk 1

P2Y12 Inhibitor Selection Algorithm

First-Line Choice for ACS

Ticagrelor is the preferred P2Y12 inhibitor for most ACS patients 1, 2

• Loading dose: 180 mg, then 90 mg twice daily 1, 2
• Preferred regardless of initial treatment strategy (PCI, medical management, or fibrinolysis) 2
• Can be used in patients with prior stroke or TIA (unlike prasugrel) 2, 3

Second-Line Choice for ACS with PCI

Prasugrel is reasonable for P2Y12 inhibitor-naïve patients undergoing PCI who have no contraindications 1, 2

• Loading dose: 60 mg, then 10 mg daily 2
• Do NOT use prasugrel if: prior stroke/TIA (Class III: Harm), age ≥75 years, or body weight <60 kg 1, 2, 3
• Do NOT use prasugrel in medically managed ACS patients (not undergoing PCI) 1, 2

Third-Line Choice (When Potent P2Y12 Inhibitors Contraindicated)

Clopidogrel is recommended when ticagrelor or prasugrel cannot be used 1, 2

• Loading dose: 600 mg (or 300 mg if age ≥75 years), then 75 mg daily 1
• Use in patients with prior intracranial bleeding or those requiring oral anticoagulation 1, 2
• Use in STEMI patients receiving fibrinolytic therapy 1

Aspirin Dosing with DAPT

Maintain aspirin at 75-100 mg daily (or 81 mg in US guidelines) when combined with any P2Y12 inhibitor 1, 2

• Higher aspirin doses increase bleeding risk without improving efficacy 1, 2

Modifying DAPT Duration Based on Bleeding Risk

High Bleeding Risk Patients

Consider shortening DAPT to 6 months in ACS patients with DES who develop high bleeding risk 1

• High bleeding risk defined as: PRECISE-DAPT score ≥25, need for oral anticoagulation, major intracranial surgery planned, or significant overt bleeding 1, 2
• This is a Class IIb recommendation (may be reasonable) 1

Low Bleeding Risk Patients

Consider extending DAPT beyond 12 months in ACS patients who tolerate therapy without bleeding complications 1, 4

• This is a Class IIb recommendation (may be reasonable) 1
• Do NOT extend if: prior bleeding on DAPT, coagulopathy, or oral anticoagulant use 1
• For extended therapy beyond 12 months, ticagrelor 60 mg twice daily (reduced dose) can be considered 4

Switching Between P2Y12 Inhibitors

From Clopidogrel to Ticagrelor

Switch early after hospital admission in ACS patients previously exposed to clopidogrel 1, 2

• Give ticagrelor 180 mg loading dose regardless of timing or loading dose of prior clopidogrel 1, 2
• Discontinue clopidogrel when starting ticagrelor 2

General Switching Principles

Always use a loading dose of the new agent when switching to avoid gaps in platelet inhibition 5

• Overlap of agents is unlikely to cause excessive bleeding compared to the more potent drug alone 5

Bleeding Risk Reduction Strategies

Implement these measures for all patients on DAPT: 1, 2

• Use radial (not femoral) arterial access for coronary angiography/PCI when performed by experienced operator 1, 2
• Prescribe a proton pump inhibitor (PPI) with DAPT to reduce gastrointestinal bleeding 1, 2
• Avoid routine platelet function testing to adjust therapy before or after elective stenting 1

Perioperative Management

Non-Cardiac Surgery

Do NOT discontinue DAPT within the first month after stent placement for elective non-cardiac surgery 1, 2

• Continue aspirin perioperatively if bleeding risk allows 1, 2
• Resume full DAPT as soon as possible postoperatively 1, 2

Critical Pitfalls to Avoid

• Never give prasugrel to patients with prior stroke/TIA - this is a Class III: Harm recommendation with increased cerebrovascular event risk 1, 2, 3
• Never stop DAPT prematurely in the first month after stent placement, even for elective surgery 1, 2
• Never use prasugrel in medically managed ACS (without PCI) - it is not recommended 1, 2
• Never fail to switch from clopidogrel to ticagrelor in ACS patients when indicated and no contraindications exist 1, 2
• Never forget to prescribe a PPI with DAPT to reduce GI bleeding risk 1, 2
• Never use high-dose aspirin (>100 mg) with DAPT - keep it at 75-100 mg daily 1, 2