Association Between the Aggregate Index of Systemic Inflammation and Slow Coronary Flow Phenomenon in Patients with Ischemia and No Obstructive Coronary Arteries

Background: Inflammation has been proposed as a potential pathogenic mechanism underlying the slow coronary flow phenomenon (SCFP). The aggregate index of systemic inflammation (AISI), a novel biomarker for evaluating inflammation, has been linked to various cardiovascular diseases. However, the relationship between AISI and the occurrence of SCFP in patients with ischemia and non - obstructive coronary arteries (INOCA) remains unclear. Methods: In this study, 1328 consecutive patients with INOCA were recruited. Among them, 90 patients had SCFP (SCFP group). A total of 180 age - and sex - matched individuals with INOCA and normal blood flow were selected as controls at a ratio of 1:2. Clinical manifestations, laboratory parameters, and angiographic features were recorded to identify potential predictors of SCFP in INOCA patients. Results: Compared with the control group, patients in the SCFP group had a higher prevalence of current smoking, as well as elevated white blood cell (WBC), neutrophil, monocyte, and platelet counts, and a higher AISI. The AISI value increased with the number of vessels affected by SCFP. Multivariate logistic regression analysis demonstrated that the WBC count and AISI were independent predictors of SCFP in INOCA patients. Additionally, when the AISI was > 264.1, the sensitivity and specificity were 64.4% and 64.4% respectively, and the area under the receiver operating characteristic curve (AUC) was 0.657 (95% CI: 0.590-0.723, P < 0.001). The AISI had a more favorable predictive value for the presence of SCFP than WBC, neutrophils, lymphocytes, monocytes, and platelets alone (P < 0.05). Conclusion: Higher AISI scores are associated with an increased risk of SCFP in INOCA patients. As an easily - obtained biomarker for assessing the degree of inflammation, the AISI can serve as a promising tool for risk stratification and appropriate management in INOCA patients.