Cor Vasa 2026, 68(5):528-532 | DOI: 10.33678/cor.2026.017

Systemic Immune-Inflammation Index Levels in Patients with Coronary Slow Flow: A Case-Control Study

Okan Tanriverdi^a, Husna Sengul Askin^b, Lutfu Askin^c, Mustafa Polat^d, Esra Polat^d

^a Department of Cardiology, Adiyaman Education and Research Hospital, Merkez/Adiyaman, Turkey

^b Department of Infectious Disease, Gaziantep City Hospital, Gaziantep, Turkey

^c Department of Cardiology, Gaziantep Islamic Science and Technology University, Gaziantep, Turkey

^d Department of Cardiology, Gaziantep City Hospital, Gaziantep, Turkey

Background: Coronary slow flow (CSF) is an angiographic occurrence marked by the protracted distal opacification of coronary arteries without the presence of substantial stenosis. While its precise pathogenesis is not fully elucidated, mounting evidence substantiates the involvement of systemic inflammation and microvascular dysfunction. The Systemic Immune-Inflammation Index (SII), based on peripheral blood counts, has lately been recognised as a reliable indicator of systemic inflammation. The objective of this study was to assess the correlation between SII levels and coronary sluggish flow in patients experiencing chest discomfort.

Methods: A total of 300 patients, aged 30 to 70 years, presenting to the emergency department or outpatient clinic with chest pain were enrolled. All individuals underwent coronary angiography and were categorised into two groups: the CSF group (n = 150) and the normal coronary flow group (n = 150). Patients with substantial coronary stenosis, valve disease, cancer, or systemic inflammatory conditions were excluded. The SII was computed as (Neutrophil count × Platelet count) / Lymphocyte count. Statistical analyses were conducted with SPSS version 25.0.

Results: Mean SII levels were markedly elevated in the CSF group relative to controls (728 ± 242 vs. 418 ± 165, p <0.001). Patients with CSF exhibited elevated neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). In multivariate logistic regression, increased SII was an independent predictor of CSF (OR = 2.41, 95% CI: 1.64-3.53, p <0.001). An examination of the receiver operating characteristic (ROC) curve indicated an appropriate SII cutoff of 560, resulting in 80% sensitivity and 75% specificity (AUC = 0.84).

Conclusion: Increased SII levels are significantly correlated with coronary sluggish flow, indicating that systemic inflammation is crucial in its pathophysiology. The SII may function as a cost-effective and readily available biomarker for risk evaluation in patients with suspected CSF.

Keywords: Biomarkers, Coronary sluggish flow, Inflammation, Microvascular dysfunction, Systemic immune-inflammation index

Received: February 7, 2026; Revised: February 7, 2026; Accepted: February 21, 2026; Prepublished online: October 5, 2026; Published: October 20, 2026  Show citation