Diagnostic Value of Systemic Inflammatory Indices in Myocardial İnfarction With Non-Obstructive Coronary Arteries: Comparison With Obstructive Myocardial Infarction and Non-Critical Coronary Artery Disease.

Background: Myocardial infarction with non-obstructive coronary arteries (MINOCA) represents a heterogeneous clinical entity with diverse underlying mechanisms, and its diagnostic evaluation remains challenging in routine clinical practice despite advances in multimodality imaging. Systemic inflammatory indices derived from routine laboratory parameters have recently gained attention as potential markers reflecting inflammatory burden in cardiovascular diseases. This study aimed to evaluate the potential diagnostic utility of systemic inflammatory indices in patients with MINOCA and to compare these indices across patients with obstructive myocardial infarction and non-critical coronary artery disease. Methods: In this retrospective single-center observational study, a total of 2,050 consecutive patients who underwent coronary angiography between January 1, 2023, and January 1, 2024 were initially screened. After applying predefined exclusion criteria, including renal failure, pulmonary embolism, cerebrovascular events, arrhythmias, severe valvular heart disease, severe anemia, and incomplete clinical data, 496 patients were eligible for the final analysis. Patients were classified into three groups according to coronary angiographic findings and troponin levels: MINOCA (n = 67), obstructive myocardial infarction (n = 222), and non-critical coronary artery disease (n = 207). Demographic characteristics, laboratory parameters, echocardiographic findings, and systemic inflammatory indices including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), and C-reactive protein-to-albumin ratio (CAR) were analyzed. Multivariable logistic regression analysis together with receiver operating characteristic (ROC) curve analysis was performed to determine independent predictors associated with MINOCA. Results: Patients with obstructive myocardial infarction were older and had a higher prevalence of diabetes mellitus and hypertension compared with the MINOCA and non-critical coronary artery disease groups (P < 0.001). Systemic inflammatory indices including neutrophil count, SII, NLR, PLR, MLR, C-reactive protein (CRP), and CAR were significantly higher in the obstructive myocardial infarction group, whereas intermediate levels were observed in the MINOCA group (P < 0.001). Left ventricular ejection fraction (LVEF) was significantly lower in the obstructive myocardial infarction group compared with the MINOCA and non-critical coronary artery disease groups (P < 0.001). In multivariate logistic regression analysis, LVEF was identified as an independent predictor of MINOCA when compared with obstructive myocardial infarction, whereas SII remained an independent predictor in comparisons between MINOCA and non-critical coronary artery disease groups. Receiver operating characteristic (ROC) curve analyses demonstrated that LVEF showed the highest diagnostic performance among the evaluated parameters. Conclusions: Systemic inflammatory indices differ significantly among patients with MINOCA, obstructive myocardial infarction, and non-critical coronary artery disease. Easily accessible inflammatory markers together with echocardiographic parameters such as LVEF may provide additional diagnostic value in the clinical evaluation of patients with suspected MINOCA.