Duration of Dual Antiplatelet Therapy after Percutaneous Coronary Intervention of Unprotected Left Main Coronary Artery Stenosis: 6 versus 12 Months

<b>Background/Objectives</b>: For patients with percutaneous coronary intervention (PCI) of an unprotected left main coronary artery (uLMCA) stenosis, the optimal duration of dual antiplatelet therapy (DAPT) remains a matter of debate. The purpose of this study was to compare clinical outcomes of 6- versus 12-month DAPT duration in patients with PCI of an uLMCA and stable angina. <b>Methods</b>: In this retrospective analysis, we included consecutive patients of our centre who underwent PCI of uLMCA stenosis for stable angina and who received DAPT with acetylsalicylic acid and clopidogrel for either 6 or 12 months. The primary endpoint was the composite of all-cause mortality, myocardial infarction, and target lesion revascularization at one year. Secondary endpoints included individual components of the primary endpoint, definite/probable stent thrombosis, and bleeding. Clinical outcomes were assessed by unadjusted analysis and by inverse probability of treatment weighting (IPTW). <b>Results</b>: Out of 984 included patients, 339 (34.5%) received DAPT for 6 months and 645 (65.5%) for 12 months. The primary endpoint occurred in 51 patients (15.2%) in the 6-month group and in 104 (16.3%) in the 12-month group (<i>p</i> = 0.674). Incidences of stent thrombosis (0.9% versus 0.3%, <i>p</i> = 0.224) and BARC 3,4,5 bleeding (6% versus 5.8%, <i>p</i> = 0.808) were also comparable in both groups. We found no significant differences in the primary endpoint and its components or BARC 3,4,5 bleeding between 6 and 12 months. <b>Conclusions</b>: Our findings do not support the extension of DAPT beyond 6 months after PCI for uLMCA in patients with stable angina.