Optimal Long-term Antiplatelet Regimen for Patients with High Ischaemic and Bleeding Risks After Percutaneous Coronary Intervention

To assess an optimal long-term antiplatelet strategy in patients at both high ischaemic and bleeding risks after percutaneous coronary intervention (PCI). Patients at high risks of both ischaemia and bleeding were eligible for inclusion. We excluded patients with any ischaemic and major bleeding complications during the mandatory period of dual antiplatelet therapy (DAPT). Clinical outcomes were evaluated in three groups of regimens, namely, clopidogrel monotherapy (CLPD), aspirin monotherapy (ASA), and DAPT group. The primary endpoint was a composite of all-cause death, myocardial infarction, stroke, or major bleeding for 12-month follow-up period. To balance characteristics according to antiplatelet strategies, stabilized inverse probability treatment weighting (IPTW) was conducted. After IPTW adjustment, CLPD group (N = 916) showed significantly lower rate of primary endpoint than DAPT group (N = 949) (hazard ratio [HR] = 2.09, 95% confidence interval [CI] = 1.22–3.60, p = 0.008), but there was no statistical difference between CLPD and ASA groups (N = 838) (HR = 1.46, 95% CI = 0.83–2.54, p = 0.187). Clinical benefits of CLPD over DAPT was mainly driven by the lower incidence of ischemic events (HR = 2.51, 95% CI 1.37–4.61; p = 0.003). Incidence of major bleeding did not differ among groups, but there was an increased bleeding tendency in DAPT group compared to CLPD group (HR = 2.51, 95% CI = 0.85–7.41, p = 0.096). For patients at high bleeding and ischaemic risk, especially undergoing complex PCI, clopidogrel monotherapy demonstrated a significant net clinical benefit compared to DAPT. Clopidogrel monotherapy showed numerical reductions of bleeding and ischaemic event rates compared to aspirin monotherapy.