From the Guidelines
Dual antiplatelet therapy (DAPT) should be continued for at least 12 months after stent placement in patients who have acute coronary syndrome (ACS), regardless of whether they received a bare metal stent (BMS) or a drug-eluting stent (DES) 1.
Indications for DAPT Duration
The decision to extend DAPT beyond 12 months should be individualized, taking into account the patient's ischemic and bleeding risk.
- Patients with high ischemic risk and low bleeding risk may benefit from extended DAPT duration 1.
- In contrast, patients with high bleeding risk may require shorter DAPT duration (3-6 months) 1.
DAPT Components
DAPT typically consists of aspirin 81mg daily indefinitely plus a P2Y12 inhibitor such as clopidogrel 75mg daily, ticagrelor 90mg twice daily, or prasugrel 10mg daily for the recommended duration.
Rationale for Extended DAPT
The extended duration of DAPT is necessary because patients with ACS remain at high risk for recurrent events due to both the stented segment and unstable plaques elsewhere in the coronary circulation 1.
- The P2Y12 inhibitor prevents platelet aggregation by a different mechanism than aspirin, providing more complete platelet inhibition and reducing the risk of stent thrombosis, which can be catastrophic with mortality rates of 20-45% 1.
Special Considerations
In patients with prior stent thrombosis, especially in the absence of correctable causes, prolonged DAPT may be beneficial 1.
- A prolonged DAPT regimen may also be considered in patients with complex PCI or those who have undergone left main or multivessel PCI 1.
From the Research
Indication for DAPT Duration
The indication to keep DAPT for 1 year after stent placement is based on several studies that have evaluated the optimal duration of dual antiplatelet therapy (DAPT) after coronary stent placement.
- Current guidelines recommend DAPT with aspirin and clopidogrel for 1 month after implantation of bare-metal stents, and for 6-12 months after implantation of drug-eluting stents (DES) 2.
- In patients with acute coronary syndrome (ACS), DAPT administration for 12 months was shown to be superior to aspirin alone for the prevention of recurrent events 2.
- A meta-analysis of short vs. prolonged DAPT after drug-eluting stent implantation found that short DAPT ≤ 3 months followed by single antiplatelet therapy (SAPT) reduces bleeding and is not associated with an increase in stent thrombosis 3.
- A systematic review and network meta-analysis of DAPT after percutaneous coronary intervention and drug-eluting stents found that extended-term DAPT was associated with a reduced risk of myocardial infarction, but also with a higher risk of major bleeding 4.
Factors Influencing DAPT Duration
The decision to extend DAPT duration should be individualized based on the patient's risk of ischemic events and bleeding.
- Patients with a high risk of ischemic recurrence, such as those with ACS, may benefit from extended DAPT 2, 4.
- Patients with a high risk of bleeding may require a shorter duration of DAPT 5, 4.
- The use of risk scores, such as the PRECISE-DAPT score, can help guide the decision on DAPT duration 5.
Clinical Evidence
Several studies have evaluated the efficacy and safety of different DAPT regimens after DES placement.
- A review of efficacy and safety studies found that the combination of clopidogrel and aspirin for 12 months is the preferred regimen for the prevention of stent thrombosis and cardiac complications after DES placement 6.
- The use of triple antiplatelet therapy, including cilostazol, has been shown to be beneficial in certain high-risk patients, such as those with diabetes mellitus 6.