Systemic Immune-Inflammation Index as a Predictor of Microvascular Dysfunction in Patients With Cardiac Syndrome X

The systemic immune inflammation index (SII; platelet count x neutrophil-lymphocyte ratio), a new marker, predicts adverse clinical outcomes in many conditions, including acute and chronic coronary syndromes, pulmonary embolism, cancers, and contrast nephropathy. The aim of this study was to determine the relationship between SII and microvascular dysfunction in patients with Cardiac Syndrome X (CSX); 105 patients with CSX and 105 patients with normal coronary arteries were included. Microvascular dysfunction was determined angiographically using myocardial blush grade (MBG) and total myocardial blush score (TMBS). We observed that the SII levels were higher in the CSX (+) group (687 [355-2211] vs 418 [198-1614], P<.001). The SII levels were also found to be significant independent predictors for CSX in multiple regression analysis (P=.001). SII levels >440 had 83.8% sensitivity and 55.2% specificity (area under the curve [AUC]: .923, 95% CI: .895-.999, P<.001) for predicting CSX. There is a significant correlation between SII levels and CSX.