Association Between Systemic Inflammation Response Index and Slow Coronary Flow Phenomenon in Patients with Ischemia and No Obstructive Coronary Arteries.

Background: Inflammation plays a key role in the pathogenesis of slow coronary flow phenomenon (SCFP). SCFP is a condition that can complicate the management of ischemia and no obstructive coronary arteries (INOCA), making it essential to identify reliable predictors. Although the systemic inflammation response index (SIRI) has been proven to relate to various cardiovascular diseases. However, the predictive value of SIRI for SCFP in patients with INOCA remains unclear. Methods: A total of 1422 patients with INOCA were consecutively included in this study. 89 individuals were diagnosed with SCFP (the SCFP group). A 1:2 age- and -sex-matched patients with INOCA and normal blood flow were selected as the control group (n=178). Plasma neutrophil, monocyte, and lymphocyte counts were collected so as to determine the value of SIRI. Results: Patients with SCFP had an elevated level of body mass index (BMI) and an increased incidence of smoking and diabetes. The SIRI was significantly higher in the SCFP group than in the controls (2.3±1.3 vs 1.8±1.3, p=0.002). The SIRI increased as the number of coronary arteries involved in the SCFP increased. Univariate analyses showed that BMI, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and SIRI were associated with SCFP. Multivariate logistic regression analysis revealed that BMI and SIRI were independent predictors of SCFP occurrence. The ROC curve showed that when the SIRI was > 1.140, the sensitivity and specificity were 87.6% and 60.1%, respectively, and the area under the ROC curve (AUC) was 0.644 (95% CI: 0.578-0.710, P < 0.001). Conclusion: The findings demonstrated that an increased SIRI may have a potential role in distinguishing SCFP in patients with INOCA. SIRI could improve the predictive value of SCFP compared to neutrophils, monocytes, and lymphocytes alone.