Dual Antiplatelet Therapy Prior to Percutaneous Coronary Intervention for Acute Coronary Syndrome: Prevalence and Outcomes in Contemporary Practice

Background: Dual antiplatelet therapy (DAPT) is standard following percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). Preloading is the practice of administering both aspirin and a P2Y12 inhibitor before PCI. DAPT preloading is common practice, however clinical trial evidence demonstrating benefit is lacking. Aims: This study aimed to examine the prevalence and associated clinical outcomes of DAPT before PCI for ACS in a contemporary population of Australian patients. Methods: Data on consecutive PCI procedures from patients included in the Victorian Cardiac Outcomes Registry (VCOR) from 2014 to 2021 was collected and stratified by administration of DAPT before PCI versus single, or no, antiplatelet therapy. Results: In total, 42,453 consecutive PCI procedures for ACS were included. Of these, 33,520 (79%) patients were either preloaded or already on DAPT before PCI. Patients on DAPT were younger (63.9 vs. 65.1, p < 0.001) and generally had fewer comorbidities. Unadjusted outcomes were more favorable with pre-loading with lower in-hospital mortality with DAPT (2.6% vs. 5.6%, p < 0.001), and 30-day cardiovascular mortality (0.3% vs. 0.4%, p = 0.039). 30-day major adverse cardiovascular events (MACE) (5.5% vs. 8.8%, p < 0.001) was similarly lower in the preloaded group. Major bleeding in hospital was less common in patients on DAPT (1.0% vs. 1.7%, p < 0.001). However, following adjustment for covariates, there was no difference in in-hospital or 30-day all-cause mortality, MACE or stent thrombosis between groups. Conclusions: DAPT before PCI is common in ACS but not independently associated with improvements in in-hospital mortality, MACE, or stent thrombosis.