Coronary slow flow: role of systemic inflammation and biomarkers in its pathophysiology

Background: Coronary slow flow (CSF) is characterized by reduced coronary blood flow velocity in the absence of significant obstruction, and it has been associated with systemic inflammation and endothelial dysfunction. This study aimed to evaluate the association between CSF and inflammatory parameters to better understand its pathophysiology and potential utility as clinical markers. Methods: A cross-sectional study was conducted in 77 patients undergoing coronary angiography, including those with CSF (n = 43) and controls with angiographically normal coronary arteries (n = 34). Clinical, biochemical, and hematological variables, TNF-α levels, and inflammatory indices (TyG, NLR, LMR, NPR, PIV, and SIRI) were assessed. Statistical tests and logistic regression were applied to identify risk factors associated with CSF. Results: The prevalence of CSF was 2.6%, with hypertension and dyslipidemia being the most frequent comorbidities. Patients with CSF exhibited significantly higher levels of total cholesterol (p = 0.024), LDL cholesterol (p = 0.016), monocytes (p = 0.017), and neutrophils (p = 0.015). Inflammatory indices TyG, NLR, NPR, PIV, and SIRI were significantly elevated in the CSF group (p < 0.05), whereas LMR was lower. No significant differences were found in TNF-α levels, although elevated values were observed in both groups. Logistic regression identified cholesterol and the SIRI index as significant risk factors for CSF. Conclusions: CSF is associated with systemic inflammation and dyslipidemia, with the SIRI index emerging as an accessible and practical tool to assess inflammation and cardiovascular risk in CSF patients. Its incorporation into clinical practice may facilitate earlier diagnosis and more effective treatment strategies. Clinical Trial number: Not applicable