Risk Stratification for Heart Failure and Death in an Acute Coronary Syndrome Population Using Inflammatory Cytokines and N-Terminal Pro-Brain Natriuretic Peptide

BACKGROUND: Inflammation in acute coronary syndrome (ACS) can identify those at greater long-term risks for heart failure (HF) and death. The present study assessed the performance of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1) (cytokines involved in the activation and recruitment of leukocytes) in addition to known biomarkers [e.g., N-terminal pro-brain natriuretic peptide (NT-proBNP)] for predicting HF and death in an ACS population. METHODS: In a cohort of 216 ACS patients, NT-proBNP (Elecsys; Roche) and IL-6, IL-8, and MCP-1 (evidence investigator; Randox) were measured in serial specimens collected early after symptom onset (n = 723). We collected at least 2 specimens from each participant: an early specimen (median 2 h; interquartile range 2-4 h) and a later specimen (9 h; 9-9 h), and used the later specimens' biomarker concentrations for risk stratification. RESULTS: An increase in both IL-6 and NT-proBNP was observed but not for IL-8 or MCP-1 early after pain onset. Kaplan-Meier analysis demonstrated that individuals with increased NT-proBNP (>183 ng/L) or cytokines (IL-6 > 6.4 ng/L; above upper limit of normal for IL-8 or MCP-1) had a greater probability of death or HF in the following 8 years (P <0.05). In a Cox proportional hazard model adjusted for both CRP and troponin I, increased IL-6, MCP-1, and NT-proBNP remained significant risk factors. Combining all 3 biomarkers resulted in a higher likelihood ratio for death or HF than models restricted to any 2 of these biomarkers. CONCLUSION: IL-6, MCP-1, and NT-proBNP are independent predictors of long-term risk of death or HF, highlighting the importance of identifying leukocyte activation and recruitment in ACS patients.