What is the recommended duration of antiplatelet therapy following stent placement?

Duration of Antiplatelet Therapy Following Stent Placement

The duration of dual antiplatelet therapy (DAPT) after stent placement depends critically on whether the indication was acute coronary syndrome (ACS) versus stable coronary disease, with aspirin continued indefinitely in all cases.

Core DAPT Duration Recommendations

For ACS Patients (Regardless of Stent Type)

• DAPT must be continued for at least 12 months after stent implantation, combining aspirin with a P2Y12 inhibitor (clopidogrel 75 mg daily, prasugrel 10 mg daily, or ticagrelor 90 mg twice daily) 1, 2.

• Aspirin 81 mg daily should be continued indefinitely after the initial post-procedure period 1, 2.

• Ticagrelor or prasugrel are strongly preferred over clopidogrel in ACS patients who lack contraindications (no prior stroke/TIA for prasugrel, not at high bleeding risk) 1, 3, 2.

For Stable Coronary Disease Patients

Drug-Eluting Stents (DES):

• Minimum 6 months of DAPT is required, though this can be shortened to 3 months in patients at high bleeding risk 1, 2.
• The original 2011 guidelines recommended 12 months for DES in stable disease if bleeding risk was not elevated 1.
• After the minimum DAPT period, transition to single antiplatelet therapy (aspirin alone) 1, 2.

Bare-Metal Stents (BMS):

• Minimum 1 month of DAPT is required, ideally extended to 12 months unless bleeding risk is elevated (then minimum 2 weeks) 1.
• After 1 month, single antiplatelet therapy is acceptable 1.

Extended DAPT Beyond 12 Months

For ACS patients who have tolerated DAPT without bleeding complications:

• Extension beyond 12 months may be considered (Class IIb recommendation), particularly in those not at high bleeding risk 1, 3, 2.

Risk-benefit analysis of extended DAPT:

• Reduces stent thrombosis (OR 0.45) and myocardial infarction (OR 0.67) 3.
• Increases major bleeding (OR 1.58) 3.
• Translates to 3 fewer stent thromboses and 6 fewer MIs but 5 more major bleeds per 1,000 patients per year 3, 2.

After 12 months in stable disease or elective PCI patients:

• Single antiplatelet therapy is recommended over continuing DAPT (Grade 1B) 1.
• The evidence suggests possible harm from prolonged DAPT beyond 12 months in non-ACS patients 1.

Shortened DAPT Duration (Recent Evidence)

Emerging data supports ultra-short DAPT (1-3 months) in select patients:

• 3-month DAPT followed by P2Y12 inhibitor monotherapy decreased net adverse clinical events without impacting major adverse cardiovascular events compared to traditional durations 4.
• High-potency P2Y12 inhibitor monotherapy (ticagrelor or prasugrel) was superior to aspirin monotherapy after the initial DAPT period 4.
• This approach is most applicable to patients at high bleeding risk 4.

Critical Decision Points

At 3 months post-stenting:

• High bleeding risk patients with stable disease who remain event-free can discontinue DAPT 2.
• ACS patients must continue to 12 months minimum 2.

At 6 months post-stenting:

• Standard stopping point for stable disease patients with DES at standard bleeding risk 1, 2.
• ACS patients at high bleeding risk may consider discontinuation 2.

At 12 months post-stenting:

• Reassess both bleeding and ischemic risks 2.
• ACS patients with low bleeding risk and high thrombotic risk may benefit from extended DAPT 3, 2.
• Stable disease patients should transition to single antiplatelet therapy 1.

Aspirin Dosing Strategy

• Low-dose aspirin 81 mg daily (range 75-100 mg) is preferred throughout DAPT and indefinitely thereafter to minimize bleeding while maintaining efficacy 1, 3, 2.
• Higher maintenance doses offer no additional benefit and increase bleeding risk 1.

Special Circumstances

Patients requiring oral anticoagulation:

• Triple therapy duration should be limited to maximum 6 months or omitted after hospital discharge 1.
• Ticagrelor or prasugrel are not recommended in this setting 1.
• These patients are at high bleeding risk and warrant shorter DAPT duration 1.

Urgent non-cardiac surgery after stenting:

• Surgery should be delayed at least 1 month after any stent type if aspirin can be maintained perioperatively 1, 2.
• If both antiplatelet agents must be stopped, bridging with cangrelor, tirofiban, or eptifibatide may be considered, especially within 1 month of stent implantation 1.

Patients with prior stent thrombosis:

• Should receive prolonged DAPT, especially if no correctable cause was identified 1.

Bleeding Risk Mitigation

Proton pump inhibitors should be used:

• In all patients with history of gastrointestinal bleeding (Class I) 1, 2.
• In patients at increased bleeding risk (advanced age, concomitant warfarin, steroids, NSAIDs, H. pylori infection) 1, 2.

Common pitfalls to avoid:

• Premature discontinuation of DAPT without cardiology consultation increases stent thrombosis risk, which carries up to 45% mortality 1, 5.
• Failing to reassess bleeding risk at 3 months using validated criteria 2.
• Using higher aspirin doses (>100 mg) unnecessarily during DAPT 1, 3.
• Continuing DAPT beyond 12 months in stable disease patients without clear high-risk features 1.