Prognostic implications of p2y12 inhibitor pre-treatment in non-st segment elevation acute coronary syndromes undergoing late invasive strategy - a national registry analysis

Abstract Background Current guidelines recommend considering P2Y12 pre-treatment (PreT) in patients (pts) with non-ST segment elevation acute coronary syndrome (NSTE-ACS) expected to undergo a late invasive strategy, based on individual bleeding risk. Purpose Investigate in-hospital morbidity and mortality in NSTE-ACS pts undergoing a late invasive strategy (coronary angiography (CAG) performed >24h post-admission) comparing those receiving P2Y12 inhibitors (P2Y12i) PreT with those who did not. Methods Retrospective multicenter analysis of NSTE-ACS pts from the Portuguese Registry on Acute Coronary Syndromes (ProACS) undergoing a late invasive strategy from October 2010 to October 2023. Exclusion criteria: previous treatment with P2Y12i or anticoagulants; atrial fibrillation. Two cohorts were defined: pts receiving PreT with P2Y12i before undergoing CAG (group 1) and pts without PreT (group 2). Comparative analyses included baseline characteristics, clinical findings, CAG findings and treatment. Primary outcome was in-hospital major adverse cardiovascular events (MACE), a composite of all-cause mortality, re-infarction, stroke and congestive heart failure. The secondary outcome included individual events and major bleeding. Results 3776 pts were included (mean age:66±12 yrs,29% female), 1530 in group 1 and 2246 in group 2. Group 1 had lower prevalence of dyslipidemia (60 vs 66%, p<0.001), prior stroke (7 vs 5%, p=0.003), myocardial infarction (16 vs 21%) and percutaneous coronary intervention (12 vs 15%) (both p=0.001). On admission, there were no differences regarding Killip-Kimball class (class I - 90 vs 90%,p=0.501) and pts in group 1 less frequently had left ventricular disfunction (left ventricular ejection fraction <50% - 20 vs 24%,p=0.032). Group 1 had higher incidence of obstructive CAD (84 vs 77%,p<0.001), more frequently required more than 1 CAG during admission (8 vs 4%,p<0.001), but multivessel disease did not significantly differ (52 vs 52%,p=0.667). Coronary angioplasty was more frequent in group 1 (63 vs 60%,p=0.019) as was coronary artery bypass graft (13 vs 10%,p=0.002). Regarding anti-thrombotics, group 1 had higher prescription rates of clopidogrel (68 vs 56%), aspirin (99 vs 81%), unfractionated heparin (21 vs 8%), enoxaparin (80 vs 56%), but lower of fondaparinux (12 vs 41%) (all p<0.001). There were no differences in the primary outcome (9 vs 9%,p=0.906) and secondary outcomes: in-hospital mortality (1 vs 1%), re-infarction (1 vs 1%), ischemic stroke (1% vs 0,4%) and congestive heart failure (7% vs 8%) (all p>0.05). Group 1 had higher rates of major bleeding (0.8 vs 0.2%, OR 3.48, CI 95% 1.22-9.89, p=0.013). Conclusions In patients with NSTE-ACS undergoing a late invasive strategy, PreT with P2Y12i showed no statistically significant differences in MACE, despite association with higher rates of major bleeding.Baseline characteristicsPrimary and secondary outcomes