Revascularization of STEMI Patients in the Subacute Stage of Myocardial Infarction and a Pharmaco-Invasive Strategy to Overcome the No-Reflow Phenomenon

The optimal timeframe for myocardial reperfusion remains a subject of ongoing debate, particularly in late-presenting patients. Historically, landmark randomized trials addressing this issue routinely excluded critically ill patients. While current clinical guidelines recommend intervention in cases of cardiogenic shock or persistent ischemia regardless of the delay late percutaneous coronary intervention (PCI) carries an inherently high risk of microvascular obstruction. A pivotal factor in this failure is the no-reflow phenomenon, driven largely by myocardial edema and subsequent extravascular compression. Consequently, evaluating targeted pathophysiological approaches to reduce myocardial edema is highly relevant.Aim. To investigate the immediate angiographic outcomes of late culprit-artery revascularization in STEMI patients and to evaluate the efficacy of selective intracoronary glucocorticoid administration as a targeted strategy for treating the no-reflow phenomenon.Materials and methods. The study included 160 patients presenting with STEMI between 2022 and 2024. The delayed-intervention subcohort comprised 22 patients with acute ischemia lasting more than 24 hours categorized into Group I (24-48 hours delay, n=13) and Group II (over 48 hours delay, n=9). All underwent drug-eluting stent implantation. To assess the treatment of the intraprocedural no-reflow phenomenon observed in the broader study population (n=29), a treatment group (n=13) received selective microcatheter-guided intracoronary administration of 250 mg methylprednisolone and was compared with a standard-care control group (n=16).Results. In patients undergoing subacute revascularization, self-sustained optimal epicardial flow (TIMI 3) post-stenting was remarkably low, being achieved in 30.8 % of Group I patients and 0% of Group II patients. Notably, all patients in the >48-hour group presented with cardiogenic shock. However, among patients who developed no-reflow, selective intracoronary administration of methylprednisolone demonstrated promising therapeutic efficacy. Successful restoration of both TIMI 3 flow and myocardial perfusion (MBG ≥3) was achieved in 76.9 % of the steroid-treated group, compared to 12.5% in the control group (OR=23.33; ARR=0.644; p24-48 hours) is entirely justified as a life-saving measure in cases of hemodynamic collapse, refractory ischemia, or malignant arrhythmias. Selective, single-dose intracoronary administration of glucocorticoids serves as a powerful, pathophysiologically grounded pharmaco-invasive tool to resolve microvascular non-reflow and restore epicardial patency.