Predictors and Outcomes of Slow Flow or No Reflow in Patients Undergoing Primary Percutaneous Coronary Intervention: A Comprehensive Analysis

Objectives: This study aims to identify predictors of slow-flow or no-reflow (SF/NR) in patients undergoing primary percutaneous coronary intervention (PCI), evaluate associated clinical outcomes, and assess the effectiveness of various medications. Methodology: We conducted a prospective observational study involving 150 patients with acute coronary syndromes (ACS) treated at Hayatabad Medical Complex from July 2023 to July 2024. Data were collected on patient demographics, clinical history, laboratory tests, and procedural details. SF/NR was defined as a TIMI flow grade of <3 following PCI. We examined the incidence of SF/NR and major adverse cardiovascular events (MACE). Statistical analyses were performed using SPSS version 25.0, with multivariate logistic regression used to identify independent predictors of SF/NR. Results: SF/NR occurred in 34.7% of patients. Significant predictors identified included advanced age, male gender, diabetes mellitus, high thrombus burden, elevated high-sensitivity C-reactive protein (Hs-CRP), and reduced estimated glomerular filtration rate (eGFR). Patients presented with both single-vessel disease (SVD) and three-vessel disease (3VD). Medications used to manage SF/NR included intracoronary adenosine and epinephrine, which demonstrated variable effectiveness in improving coronary flow and reducing myocardial damage. Patients with SF/NR experienced significantly higher rates of MACE: cardiac death (10 vs. 2), recurrent myocardial infarction (8 vs. 3), target vessel revascularization (5 vs. 1), and heart failure (12 vs. 5). Multivariate analysis confirmed diabetes mellitus (OR: 1.56, CI: 1.12-2.18), high thrombus burden (OR: 2.33, CI: 1.60-3.39), and elevated Hs-CRP (OR: 1.45, CI: 1.01-2.07) as independent predictors of SF/NR. Conclusion: SF/NR represents a significant complication during primary PCI, with severe adverse outcomes. Key predictors include renal dysfunction, diabetes mellitus, and high thrombus burden. Intracoronary adenosine and epinephrine were used with varying effectiveness. Future research should focus on refining management strategies and improving patient outcomes.