Abstract Body (Do not enter title and authors here): Background: Coronary artery disease (CAD) is a major cause of morbidity and mortality worldwide. Chronic inflammation is a known risk factor for atherosclerosis, plaque formation, disease progression, and plaque instability. Novel inflammatory biomarkers have been recently linked to excess risk of adverse cardiovascular events, including incident myocardial infarction. Elevated inflammatory biomarkers may help identify patients at higher risk for severe CAD.
Aim: This study aimed to evaluate the use of novel systemic inflammatory markers in predicting the pretest probability of severe CAD in patients referred to diagnostic coronary angiography in a single tertiary care center.
Methods: This was a prospective observational cohort study enrolling consecutive patients referred to diagnostic coronary angiography in a tertiary care center. Preprocedural laboratory results were obtained from medical charts, including complete blood counts with differentials. Three novel systemic inflammatory markers were computed using existing mathematical formulas: systemic immune-inflammation index (SII = neutrophil count*platelet/lymphocyte); systemic inflammation response index (SIRI = neutrophil*monocyte/lymphocyte); and systemic immune inflammatory response index (SIIRI = neutrophil*monocyte*platelet/lymphocyte). The primary study outcome was severe CAD defined as the presence of ≥70% stenosis in one of three main coronary arteries requiring percutaneous coronary intervention). The outcome was adjudicated by an independent reviewers blinded to computations of biomarkers.
Result: The sample included 264 patients (age 59.3±10.8, 47% Females). Overall, 84 patients (32%) met the primary study outcomes. In univariate analysis, those with severe CAD had significantly higher SIRI (2.9±0.7 vs. 2.6±0.6, p = 0.001) and SIIRI (8.4±0.8 vs. 8.1±0.7, p = 0.015) compared to their counterparts. In multivariate analysis adjusted for age and sex, only SIRI was an independent predictor of severe CAD. Using SIRI > 20.8 (upper quartile) was associated with nearly three-fold excess risk of severe CAD (OR = 2.72, 95% CI 1.45-5.09).
Conclusion: Elevated SIRI, a marker of ongoing systemic inflammatory response, could be indicative of severe CAD. As an inexpensive biomarker based exclusively on complete blood count, SIRI can be used to prioritize patients referred for diagnostic angiography and potentially expedite treatments in those at higher risk for coronary events.