Andrea Dias Stephanus ¹ Alice Pacheco Santos ¹ Ana Carolina Machado Rodrigues da Cunha ¹ Ana Carolina Augusto Rocha ¹ Amanda de Amorim Meireles ¹ Mariana Guimaraes de Oliveira ¹ Pietra Arissa Coelho Matsunaga ¹ Alexandre Anderson De Sousa Munhoz Soares ^2,3 Ana Claudia Cavalcante Nogueira ^2,3,4 Adriana de Jesus Benevides de Almeida Guimaraes ⁴ Gustavo Alexim ⁴ Alessandra Menezes Campos Staffico ⁵ Luiz Sérgio Fernandes de Carvalho ^1,2*

• ¹ Catholic University of Brasilia (UCB), Brasília, Brazil
• ² Clarity Healthcare Intelligence, Jundiai, Brazil
• ³ Aramari Apo Institute, Brasilia, Brazil
• ⁴ State Department of Health of the Federal District (SES-DF), Brasilia, Brazil
• ⁵ Creighton University, Omaha, Nebraska, United States

Background. The pharmacoinvasive (PhI) strategy is the standard-of-care for ST-elevation myocardial infarction (STEMI) patients when primary percutaneous coronary intervention (pPCI) is unfeasible. Optimal timing for post-fibrinolytic PCI (lysis-PCI) remains elusive. Therefore, this study aimed to assess the clinical and economic impacts of early versus delayed lysis-PCI in patients with STEMI.Methods. This retrospective cohort study included 1,043 STEMI patients classified by lysis-PCI timing. The primary outcome was in-hospital major adverse cardiovascular events (4p-MACE), with secondary outcomes such as 3p-MACE, in-hospital mortality, and costs. Multivariable logistic regression models were used to assess the association between lysis-PCI timing and outcomes. Cost analyses were conducted from the perspective of Brazilian public healthcare system, with values converted to international dollars (Int$) for broader applicability.Results. Every 4-hour delay in lysis-PCI was associated with a 44% reduction in in-hospital mortality [OR=0.560 (95%CI: 0.381-0.775); p=0.001] and a 13% decrease in 4p-MACE [OR=0.877 (95%CI: 0.811-0.948); p=0.001]. Additionally, 4-hour delay in lysis-PCI was also associated with a significant reduction in in-hospital costs (Int$916.20±99) and disease-induced years of productivity lost (β= -41.79±151 years; p=0.001). These significant trends remained consistent even after adjusting for confounders and applying propensity score matching. Older adults (aged ≥80) experienced an increase in 3p-MACE with earlier lysis-PCI.Delaying lysis-PCI was found to be associated with reduced in-hospital cardiovascular adverse events and lower costs, particularly among older adults. Further research should develop evidence-based lysis-PCI protocols that optimize both clinical outcomes and cost-effectiveness.