Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 21 3 2026 06 07 214 220 Suryono Suryono Department of Cardiology and Vascular Medicine, Faculty of Medicine, University of Jember/dr. Soebandi Regional Hospital, Jember, Indonesia Achmad Ilham Tohari Department of Epidemiology and Preventive Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan Muhammad Rijal Fahrudin Hidayat Faculty of Medicine, University of Jember, Jember, East Java, Indonesia Muhammad Irsyad Amien Faculty of Medicine, University of Jember, Jember, East Java, Indonesia Muhammad Farhan Hibatulloh Faculty of Medicine, University of Jember, Jember, East Java, Indonesia Muhammad Naufal Hibatullah Faculty of Medicine, University of Jember, Jember, East Java, Indonesia Hazbina Fauqi Ramadhan Kalisat General Hospital, Jember, East Java, Indonesia 2026 02 22 2026 06 07 Background: Primary percutaneous coronary intervention (PCI) remains the main treatment for patients with ST-segment elevation myocardial infarction (STEMI). Nonetheless, many patients still miss the primary PCI golden period or refuse it, especially in developing countries, such as Indonesia. This study compared the effects of delayed PCI (12–48 hours after STEMI onset) and optimal medical therapy (OMT) on cardiac remodeling biomarkers matrix metalloproteinase-9 (MMP-9), nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2), and transforming growth factor-β1 (TGF-β1). Methods: This quasi-experimental study enrolled 55 patients with STEMI. Initially, all participants were advised to undergo delayed PCI. Patients who agreed to receive delayed PCI plus OMT were included in group 1 (n=24), and those who refused delayed PCI were included in group 2 and received OMT only. Blood samples were drawn at 24 hours and on day 5 after the intervention. MMP-9, NOX2, and TGF-β1 levels were measured using enzyme-linked immunosorbent assay. Data were analyzed using Stata, version 17. Results: Group 1 showed significant reductions at 24 hours and day 5 in MMP-9 (Cohen d: −0.97, P<0.01 and −0.91, P<0.01, respectively), TGF-β1 (Cohen d: −0.64, P=.01 and −0.73, P<0.01, respectively), and NOX2 (Cohen d: −0.68, P=0.04 and −0.37, P=0.04, respectively) compared with group 2. No significant difference was observed between 24 hours and day 5 within each intervention group. Conclusion: Delayed PCI performed within 12–48 hours was associated with significantly lower circulating levels of MMP 9, NOX2, and TGF β1 at 24 hours and 5 days compared with OMT alone in STEMI patients with stable conditions. https://rhythm.tums.ac.ir/index.php/jthc/article/view/2438 https://rhythm.tums.ac.ir/index.php/jthc/article/download/2438/1275