Endothelial stress ratio as a predictor of the no-reflow phenomenon in patients with acute coronary syndrome: a retrospective study.

INTRODUCTION: The no-reflow phenomenon is a major complication in patients with acute coronary syndrome undergoing percutaneous coronary intervention, significantly impacting prognosis. Endothelial dysfunction and systemic inflammation are central to its pathogenesis. AIM: This study aimed to evaluate the predictive value of the endothelial stress ratio - a novel composite index incorporating fibrinogen, albumin, C-reactive protein, and lymphocyte count - for the occurrence of the no-reflow phenomenon in patients with acute coronary syndrome. MATERIAL AND METHODS: This retrospective study included 1256 patients with acute coronary syndrome treated with percutaneous coronary intervention. Clinical and procedural data, including Killip class, presentation type, and angiographic findings such as infarct-related artery, multivessel disease, and pre-procedural Thrombolysis in Myocardial Infarction flow, were evaluated. The endothelial stress ratio was calculated using pre-procedural blood samples. To address multicollinearity, two separate multivariate logistic regression models were constructed: Model 1 included the fibrinogen-to-albumin ratio, while Model 2 evaluated the independent predictive value of the endothelial stress ratio alongside clinical variables. RESULTS: The no-reflow phenomenon occurred in 73 (5.8%) patients. Patients with no-reflow had significantly higher endothelial stress ratio values (138 (102-198) versus 72 (49-104), p < 0.001). In multivariate analysis, the endothelial stress ratio was the strongest independent predictor of no-reflow (Model 2, odds ratio: 1.48, 95% confidence interval: 1.21-1.82, p < 0.001). Receiver operating characteristic analysis demonstrated a strong discriminative performance, with an area under the curve of 0.82 (p < 0.001). CONCLUSIONS: The endothelial stress ratio is a novel, independent biomarker for predicting no-reflow. Incorporating this ratio into pre-procedural assessment may help identify high-risk patients and guide therapeutic strategies.