New Insights Into Long- Versus Short-Term Dual Antiplatelet Therapy Duration in Patients After Stenting for Left Main Coronary Artery Disease: Findings From a Prospective Observational Study

Background: The appropriate duration of dual antiplatelet therapy (DAPT) and risk-benefit ratio for long-term DAPT in patients with left main (LM) disease undergoing percutaneous coronary intervention remains uncertain. Methods: Four thousand five hundred sixty-one consecutive patients with stenting of LM disease at a single center from January 2004 to December 2016 were enrolled. Decision to discontinue or remain on DAPT after 12 months was left to an individualized decision-making based on treating physicians by weighing the patient's risks of ischemia versus bleeding and considering patient preference. The primary outcome was a composite of death, myocardial infarction, stent thrombosis, or stroke at 3 years. Key safety outcome was 3-year rate of Bleeding Academic Research Consortium 2, 3, or 5 bleeding. Results: Of 3865 patients free of ischemic and bleeding events at 12 months, 1727 (44.7%) remained on DAPT (mostly clopidogrel based [97.7%]) beyond 12 months after LM percutaneous coronary intervention. DAPT>12-month versus <= 12-month DAPT was associated with a significant reduced risk of 3-year primary outcome (2.6% versus 4.6%; adjusted hazard ratio: 0.59 [95% CI, 0.41-0.84]). The same trend was found for other ischemic end points: death (0.9% versus 3.0%; Plog-rank<0.001), cardiovascular death (0.5% versus 1.7%; Plog-rank=0.001), myocardial infarction (0.8% versus 1.9%; Plog-rank=0.005), and stent thrombosis (0.4% versus 1.1%; Plog-rank=0.017). The key safety end point was not significantly different between 2 regimens (1.8% versus 1.6%; adjusted hazard ratio: 1.07 [95% CI, 0.65-1.74]). The effect of DAPT>12 month on primary and key safety outcomes was consistent across clinical presentations, high bleeding risk, P2Y(12) inhibitor, and LM bifurcation percutaneous coronary intervention approach. Conclusions: In a large cohort of patients free from clinical events during the first year after LM percutaneous coronary intervention and at low apparent future bleeding risk, an individualized patient-tailored approach to longer duration (>12 month) of DAPT with aspirin plus a P2Y(12) inhibitor (mostly clopidogrel) improved both composite and individual efficacy outcomes by reducing ischemic risk, without a concomitant increase in clinically relevant bleeding.