Investigation of osteopontin level in coronary slow flow

Coronary slow flow(CSF) is a significant coronary angiographic phenomenon characterized by the delayed progression of contrast medium in the coronary arteries in the absence of obstructive coronary artery disease (CAD). The underlying pathophysiological mechanisms of the CSF pattern have not yet been clearly identified. Potential mechanisms that have been evaluated to date include microvascular dysfunction, endothelial dysfunction, vasomotor dysfunction, small vessel disease, diffuse atherosclerosis, inflammation, oxidative stress, and increased platelet aggregation. Osteopontin (OPN) exacerbates the inflammatory response by facilitating the accumulation of immune system cellular components, such as macrophages and monocytes, in the vascular endothelium. The migration of these cells to the endothelial surface leads to progression of the inflammatory process in the vessel wall and deterioration of endothelial functions. Furthermore, OPN increases the expression of adhesion molecules such as ICAM-1 and VCAM-1 in endothelial cells, thereby facilitating the attachment of immune cells to the vessel wall, which contributes to the persistence of inflammation. On the other hand, it has been shown that OPN enhances the production of reactive oxygen species via NADPH oxidase, thereby increasing oxidative stress and reducing nitric oxide (NO) bioavailability. In this study, we aimed to investigate the relationships between OPN and other blood parameters associated with endothelial dysfunction, inflammation, and oxidative stress in patients diagnosed with CSF. A total of 80 patients who underwent coronary angiography at the Cardiology Clinic of Süleyman Demirel University Research and Training Hospital between September 2024 and February 2025 were included in the study. Of these, 40 patients were diagnosed with CSF, and 40 patients had normal coronary arteries. Serum OPN levels and other parameters were compared between the CSF group and the healthy group. In our study, the osteopontin (OPN) level was measured as 17.08 ± 8.31 U/L in the CSF group and 9.79 ± 2.50 U/L in the healthy control group, with a statistically significant difference between the two (p<0.001). Correlation values between OPN levels and TIMI frame count (TFC) measurements were analyzed in both the CSF and control groups. In the control group, a strong and significant positive correlation was found between OPN and all TFC calculations. The highest correlation was observed between OPN and mean TIMI (r=0.638; p<0.001). Similarly, in the CSF group, a strong and significant positive correlation was observed between OPN and TFC measurements. Higher correlation values were noted with mean TIMI and TIMI-LAD (r=0.876 and r=0.789, respectively; p<0.001). The OPN marker was found to be effective in predicting the CSF group. The area under the curve (AUC) was calculated as 0.839 (p<0.001). The cut-off value was determined to be approximately 11. Accordingly, the diagnostic performance yielded a sensitivity of 82.5% and a specificity of 72.5%. 60 Considering that endothelial dysfunction, inflammation and oxidative stress play a role in the pathogenesis of CSF, OPN is important for a better understanding of the disease and the development of possible new treatment strategies. Keywords: Osteopontin (OPN), Coronary slow flow (CSF), TIMI frame count (TFC)