Is dual antiplatelet therapy (DAPT) necessary post LAD stenting?

DAPT is Absolutely Required Post-LAD Stenting

Yes, dual antiplatelet therapy (DAPT) is mandatory after LAD stenting to prevent catastrophic stent thrombosis, which results in death or myocardial infarction in 64.4% of cases, with mortality rates of 20-45%. 1

Minimum Required DAPT Duration

The duration depends on stent type and clinical presentation:

For Bare-Metal Stents (BMS)

• Minimum 1 month of DAPT (aspirin + clopidogrel 75mg) is required 1
• After 1 month, aspirin 75-162mg should be continued indefinitely 2

For Drug-Eluting Stents (DES)

• Standard duration is 6 months for stable coronary artery disease patients regardless of stent type 1
• 12 months is recommended if the patient is not at high bleeding risk 1
• The original 2007 AHA/ACC guidelines recommended minimum durations of 3 months for sirolimus-eluting stents and 6 months for paclitaxel-eluting stents, but ideally up to 12 months 1

For Acute Coronary Syndrome (ACS) Presentations

• 12 months of DAPT is the Class I recommendation (Level of Evidence A) 1
• This applies to both STEMI and NSTEMI presentations 3

DAPT Regimen Specifics

Standard Combination

• Aspirin 75-325mg daily (lower doses of 75-162mg preferred long-term due to fewer bleeding complications) 2
• Plus a P2Y12 inhibitor:
  • Clopidogrel 75mg daily (standard for stable CAD) 1
  • Ticagrelor 90mg twice daily (for ACS) 3
  • Prasugrel 10mg daily (for ACS in appropriate patients) 3

P2Y12 Inhibitor Selection

• For stable CAD with elective PCI: clopidogrel is preferred 1
• Ticagrelor did not reduce periprocedural MI compared to clopidogrel in stable CAD and increased minor bleeding 1
• For ACS: ticagrelor or prasugrel are preferred over clopidogrel 3

Risk-Based Duration Modification

High Bleeding Risk Patients (PRECISE-DAPT Score ≥25)

• Shorten DAPT to 3-6 months 1
• The PRECISE-DAPT score integrates age, creatinine clearance, hemoglobin, white blood cell count, and prior spontaneous bleeding 1
• After shortened DAPT, continue aspirin indefinitely 1

High Ischemic Risk Patients (DAPT Score ≥2)

• Consider extending DAPT beyond 12 months (up to 24-36 months) 1
• High ischemic risk features include: diabetes, prior MI, multivessel CAD, chronic kidney disease, complex lesions (left main, proximal LAD, bifurcation, multiple overlapping stents) 1
• The DAPT score ranges from -2 to 10; scores ≥2 suggest benefit from prolonged therapy 1

Critical LAD-Specific Considerations

Multiple Overlapping LAD Stents

• Patients with three overlapping stents in the LAD require prolonged or even lifelong DAPT if tolerated, as the risk of stent thrombosis remains substantially elevated 4
• After a first stent thrombosis event, the long-term risk of recurrent thrombosis is high, reinforcing the need for indefinite DAPT continuation 4
• The requirement for three sequential stents should trigger Heart Team discussion favoring CABG over continued PCI, especially given the LAD's critical territory 4

Very Late Stent Thrombosis Risk

• Very late stent thrombosis can occur 20 months or more after implantation, even with newer-generation DES, particularly after DAPT discontinuation 4
• This risk is especially pronounced in the LAD territory where thrombosis is more likely to be fatal 1

Absolute Contraindications to DAPT Discontinuation

Never Stop DAPT Without Cardiologist Consultation

• Patients must be explicitly instructed before hospital discharge to contact their treating cardiologist before stopping any antiplatelet therapy, even if another healthcare provider instructs them to stop 2
• Premature discontinuation greatly increases the risk of stent thrombosis, myocardial infarction, and death 1
• In one study, 6 of 7 patients who stopped their thienopyridine before surgery within 90 days of stent placement died in a manner suggestive of stent thrombosis 2

Surgical Procedures

• All elective surgical procedures should be postponed until 12 months after DES implantation 1, 2
• For bare-metal stents, elective surgery should be delayed for at least 1 month 2
• If surgery absolutely cannot be deferred, aspirin should be continued during the perioperative period if at all possible, and the P2Y12 inhibitor should be restarted as soon as possible after the procedure 1, 2

Common Clinical Pitfalls

Premature Discontinuation

• Complete interruption of DAPT is an independent predictor of stent thrombosis and mortality, particularly catastrophic in patients with multiple overlapping stents 4
• Many patients and healthcare providers prematurely discontinue DAPT, which greatly increases risk 1

Inadequate Patient Education

• Patients must understand that stopping antiplatelet medications prematurely can cause fatal stent thrombosis, heart attack, or death 2
• Patients should carry a card or wear medical alert identification stating they have a coronary stent and the date of implantation 2

Stent Underexpansion

• Stent underexpansion or undersizing frequently contributes to stent thrombosis and should be assessed with imaging guidance (OCT or IVUS) when stents are placed 4

Bleeding Risk Underestimation in Elderly

• Bleeding risk is significantly increased with DAPT in elderly patients (>70 years), particularly those with renal dysfunction 5
• The PRECISE-DAPT score should be calculated to guide duration in these patients 1

Alternative Strategies After Initial DAPT Period

P2Y12 Inhibitor Monotherapy

• In selected high ischemic risk patients without high bleeding risk, ticagrelor 90mg twice daily monotherapy may be considered after 3 months of DAPT 1
• This strategy showed reduced bleeding with no increase in ischemic events in the TWILIGHT trial 1
• However, this is not contemplated by the European Medicines Agency at the time of the 2024 ESC guidelines 1

Extended Dual Pathway Inhibition

• For patients with prior MI 1-3 years previously and high-risk characteristics (age >65, diabetes, second MI, multivessel CAD, or CKD), ticagrelor 60mg twice daily plus aspirin reduced ischemic events at 3 years compared to aspirin alone 1
• This increases TIMI major (but not fatal) bleeding 1