Prognostic Value of the Platelet-to-Lymphocyte Ratio in Patients With Acute Coronary Syndrome and Its Correlation With Angiographic Findings

Introduction Acute coronary syndrome (ACS) is a major manifestation of coronary heart disease and is associated with significant morbidity and mortality. Inflammatory and thrombotic mechanisms play an important role in its pathogenesis. The platelet-to-lymphocyte ratio (PLR) has emerged as a simple and readily available inflammatory marker that may have prognostic value. The present study aimed to evaluate the association between PLR and major adverse cardiovascular events (MACE) in patients with ACS. Materials and methods This prospective observational study was conducted at a tertiary care center after institutional ethics approval. A total of 640 consecutive patients aged more than 18 years presenting with ACS and meeting the inclusion and exclusion criteria were enrolled after obtaining informed consent. PLR was measured from blood samples collected within 12 hours of symptom onset and prior to reperfusion or heparin therapy. Demographic details, clinical history, and laboratory parameters were recorded. SYNTAX scores, PLR, and neutrophil-to-lymphocyte ratio (NLR) were calculated. MACE were defined as the occurrence of heart failure, recurrent myocardial infarction, or death during the in-hospital period. Patients were followed until discharge or in-hospital death. Patients with incomplete laboratory or outcome data were excluded from the final analysis. Multivariate regression analysis was performed to adjust for potential confounding variables. Results The mean age of the study population was 62.01 ± 11.66 years, with a female preponderance (59.22%). MACE occurred in 316 patients (49.38%). Patients with MACE had significantly higher PLR and NLR values and lower ejection fraction (EF) compared with those without MACE (p < 0.001). A higher proportion of patients with a SYNTAX II score greater than 22 experienced MACE compared with those with lower scores (80.20% vs 21.66%, p < 0.001). PLR demonstrated a significant positive correlation with NLR and SYNTAX I score and a negative correlation with EF. Similar associations were observed across ACS subgroups, including non-ST-elevation myocardial infarction, ST-elevation myocardial infarction, and unstable angina. Conclusions Higher PLR levels were associated with greater angiographic disease severity and an increased incidence of in-hospital MACE in patients with ACS. These findings suggest that PLR may serve as a useful adjunctive marker for risk assessment in ACS. Further multicenter prospective studies with longer follow-up are required to validate its prognostic role.