Serial Measurement of Monocyte Chemoattractant Protein-1 After Acute Coronary Syndromes : Results From the A to Z Trial

ObjectivesThis study sought to determine whether the novel biomarker monocyte chemoattractant protein (MCP)-1 adds prognostic value to standard risk assessment tools and biomarkers after acute coronary syndromes (ACS).BackgroundMonocyte chemoattractant protein-1 is a chemokine recruiting signal for monocytes that may function as both a mediator and biomarker of ACS.MethodsMonocyte chemoattractant protein-1 was measured at baseline (n = 4,244), 4 months (n = 3,603), and 12 months (n = 2,950), and correlated with clinical events in the Z phase of the A to Z (Aggrastat to Zocor) trial, which compared early intensive versus delayed and less intensive statin therapy after ACS.ResultsRates of death and the composite end points of death or myocardial infarction (MI); death, MI, or heart failure; and cardiovascular death, MI, readmission for ACS, or stroke increased across baseline quartiles of MCP-1 and among patients with MCP-1 greater than versus less than or equal to the pre-specified threshold of 238 pg/ml (p < 0.01 for each). After adjustment for standard risk predictors and levels of C-reactive protein and B-type natriuretic peptide, MCP-1 >238 pg/ml remained independently associated with mortality (hazard ratio 2.16; 95% confidence interval 1.54 to 3.02) and with each composite end point, and increased the C-statistic of the fully adjusted mortality model from 0.76 to 0.78 (p < 0.0001). A value of MCP-1 >238 pg/ml at the 4-month follow-up visit was also independently associated with mortality after 4 months (hazard ratio 1.76; 95% confidence interval 1.12 to 2.76). Elevated MCP-1 levels did not identify patients who derived incremental benefit from intensive statin therapy.ConclusionsMonocyte chemoattractant protein-1 provides independent prognostic value in the acute and chronic phases after ACS and merits further evaluation as a prognostic marker and potential therapeutic target.