Impact of P2Y12 inhibitor pretreatment before coronary angiography in high risk NSTE-ACS: A comparative cohort analysis

Background / Introduction Administration of P2Y12 inhibitor before coronary angiography (a practice usually adressed as 'pretreatment') in patients with high-risk non-ST-segment elevation acute coronary syndrome (NSTE-ACS) remains common practice in some centres, despite last 2023 ESC Acute Coronary Syndrome guidelines recommendations against its routine use. The rationale for prompt dual antiplatelet therapy originates from old studies not specifically designed to evaluate this strategy. When logistical delays prevent performing angiography within 24 hours, there is a perceived increase in ischaemic risk, thus leading to pretreatment. Purpose To assess whether pretreatment with P2Y12 inhibitor before early coronary angiography (<24 h) provides clinical benefit comparing two cohorts of high-risk NSTE-ACS with a pretreatment and a non-pretreatment protocol. Methods We conducted a comparative analysis between two cohorts of high-risk NSTE-ACS patients undergoing coronary angiography within 24 hours. The first cohort (2014–2016) routinely received P2Y12 inhibitor pretreatment, whereas the second cohort (2017–2024) followed a protocol without pretreatment. In the latter, patients received aspirin and enoxaparin, and the P2Y12 inhibitor was administered orally in the catheterisation laboratory (crushed tablet). Patients requiring emergent PCI due to cardiogenic shock or ongoing ischaemia were excluded. Primary endpoint was the composite of acute stent thrombosis, conversion to primary PCI, and major adverse cardiovascular events (MACE). Secondary endpoints included bleeding and a combined endpoint of MACE and bleeding (net adverse clinical events adressed as NACE). Results Baseline characteristics and outcomes are shown in the accompanying table (figure 1). The pretreated patients cohort had higher prevalence of cardiovascular risk factors and previous coronary artery disease. Clopidogrel use was significantly higher in the pretreatment group, consistent with the historical treatment period. With respect to the endpoints of our study, we found no significant differences in stent thrombosis (0.3% vs 0.5%) or conversion to primary PCI (0.3% vs 0.9%) rates. However, pretreatment cohort had a significantly higher rate of MACE (2.8% vs 0.7%, p = 0.022), likely reflecting higher baseline comorbidity. There were no significant differences in bleeding events (1.5% vs 1.4%) or NACE (4.2% vs 2.5%). Conclusion(s) In this single-centre study, pretreatment with a P2Y12 inhibitor before early coronary angiography in high-risk NSTE-ACS did not confer clinical benefit compared with a contemporary non-pretreatment protocol.