Is Left Main Trunk (LMT) disease an indication for Dual Antiplatelet Therapy (DAPT)?

Is Left Main Trunk Disease an Indication for DAPT?

Yes, left main (LM) coronary artery disease treated with PCI absolutely requires DAPT, with a minimum duration of 12 months recommended for optimal outcomes, and consideration for extended therapy beyond 12 months in patients who tolerate treatment without bleeding complications. 1, 2

Standard DAPT Duration for LM Disease

• The default DAPT duration is 12 months for all patients undergoing LM PCI, regardless of whether the clinical presentation is acute coronary syndrome or stable coronary artery disease. 1, 2

• DAPT duration of less than 12 months after LM PCI is associated with significantly higher rates of major adverse cardiovascular events (MACE), including a 4.51-fold increased risk for DAPT <6 months and 1.92-fold increased risk for DAPT 6-12 months compared to 12-24 months. 3

• The standard regimen consists of aspirin plus a P2Y12 inhibitor (clopidogrel, ticagrelor, or prasugrel depending on clinical presentation). 1, 2

Extended DAPT Beyond 12 Months

For patients who complete 12 months of DAPT without bleeding complications and remain at low bleeding risk, extended DAPT beyond 12 months should be strongly considered for LM disease. 1, 2, 4

• Extended DAPT (>12 months) in LM patients reduces the composite endpoint of death, MI, stent thrombosis, or stroke (2.6% vs 4.6% at 3 years; adjusted HR 0.59,95% CI 0.41-0.84). 4

• Specific benefits of prolonged DAPT in LM disease include:

  • Reduced all-cause mortality (0.9% vs 3.0%) 4
  • Reduced cardiovascular death (0.5% vs 1.7%) 4
  • Reduced myocardial infarction (0.8% vs 1.9%) 4
  • Reduced stent thrombosis (0.4% vs 1.1%) 4

• Importantly, extended DAPT in LM patients does not significantly increase major bleeding risk (1.8% vs 1.6%; adjusted HR 1.07,95% CI 0.65-1.74). 4

High Bleeding Risk Patients

For high bleeding risk patients with LM disease, shortened DAPT to 6 months may be considered, but this represents a compromise between bleeding and ischemic risk. 1, 2

• Even in high bleeding risk patients, DAPT duration <6 months after LM PCI carries substantially elevated ischemic risk. 3

• When shortened DAPT is necessary, gastric protection with a proton pump inhibitor is mandatory. 1

LM Disease as Complex PCI

LM PCI is inherently considered complex anatomy, which further supports prolonged DAPT duration. 1

• Complex PCI features that apply to LM disease include:

  • Bifurcation lesions requiring two stents 1
  • Total stent length >60 mm 1
  • Multiple lesions treated 1

• Prolonged DAPT (>6 months) may be considered specifically for patients who undergo complex PCI, which encompasses most LM interventions. 1

Critical Procedural Considerations

Ad hoc PCI for LM stenosis in stable patients is highly discouraged because it prevents proper Heart Team discussion and adequate P2Y12 inhibitor pretreatment. 1

• LM stent thrombosis carries catastrophic consequences, as illustrated by case reports of cardiogenic shock from LM stent thrombosis occurring just 10 days post-procedure. 1

• For elective LM PCI, P2Y12 inhibitor pretreatment should be initiated to reach steady state before the procedure. 1

Common Pitfalls to Avoid

• Never discontinue both antiplatelet agents simultaneously in LM patients, as this dramatically increases thrombotic risk. 2, 5

• Failing to reassess DAPT at 12 months is a critical error—an active decision must be made to continue or discontinue therapy based on bleeding and ischemic risk. 2

• Do not assume that LM disease follows the same DAPT duration as non-LM coronary disease; the anatomical significance and consequences of thrombosis are far greater. 4, 3

• Avoid using bare metal stents to justify shorter DAPT duration—newer-generation drug-eluting stents with appropriate DAPT duration are preferred. 1