Inflammation in acute coronary syndrome: prognostic significance

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background In patients with acute coronary syndrome (ACS) the acute phase reactant, C-reactive protein (CRP), might be significantly elevated. Several reports suggest that CRP may play a direct pathophysiological role on the development and progression of atherosclerosis, and CRP values correlate with infarct size when measured by magnetic resonance imaging. Purpose The aim of the present study was to evaluate the prognostic value of CRP in patients presenting with an ACS. Methods Retrospective analysis of 635 consecutively admitted patients due to ACS in a single coronary intensive care unit. CRP levels were measured at admission. Clinical variables and therapeutic strategies were examined. The primary endpoint analysed during follow-up was all-cause mortality. Possible predictors for all-cause mortality were assessed by Cox regression models. When statistically significant values were found in univariate analysis, multivariate analysis was used to determine whether CRP was an independent predictor of outcome. Results In the studied sample, 75% were male. Median age was 69 [interquartile range (IQR) 57–78]. ST-elevation myocardial infarction (STEMI) occurred in 39.6%, non-ST segment elevation myocardial infarction in 44.9% and unstable angina in 15.5% of the patients. Median left ventricular ejection fraction (LVEF) was 48% (IQR 40–55%) and median CRP level at admission 0.7 mg/dL (IQR 0.5–1.9 mg/dL). Regarding important comorbidities and past medical history, 75.9% had hypertension (HTN), 34.0% diabetes, 20.3% chronic kidney disease (CKD), 68.6% dyslipidaemia and 17.3% heart failure (HF). The median follow-up was 34 months (IQR 22–72). In univariate analysis, CRP was significantly associated with all-cause mortality (HR 1.06 per 1 mg/dL increase, 95% CI 1.04–1.08, p<0.001), as was gender, age, LVEF, STEMI and previous history of diabetes, HTN, CKD or HF. In multivariate analysis, CRP remained significantly associated with the primary endpoint (HR 1.02, 95% CI 1.00–1.05, p=0.033), as did age, LVEF and previous history of HF. Conclusions In our study, CRP at admission was an independent risk factor for all-cause mortality following an ACS. This finding indicates that inflammation associated with the acute event has a significant impact in the long-term prognosis. More evidence is needed to determine if treating inflammation (and when, in the course of the disease) could result in better outcomes.