We aimed to identify a novel biomarker involved in the early events leading to an acute coronary syndrome (ACS) and evaluate its role in diagnosis and risk stratification.
Biomarker identification was based on gene expression profiling. In coronary thrombi of ACS patients, cysteine-rich angiogenic inducer 61 (Cyr61, CCN1) gene transcripts were highly up-regulated compared with peripheral mononuclear cells. In a murine ischaemia-reperfusion model (I/R), myocardial Cyr61 expression was markedly increased compared with the controls. Cyr61 levels were determined in human serum using an enzyme-linked immunosorbent assay. Cohorts of ACS (n = 2168) referred for coronary angiography, stable coronary artery disease (CAD) (n = 53), and hypertrophic obstructive cardiomyopathy (HOCM) patients (n = 15) served to identify and evaluate the diagnostic and prognostic performance of the biomarker. Cyr61 was markedly elevated in ST-elevation myocardial infarction patients compared with non-ST-elevation myocardial infarction/unstable angina or stable CAD patients, irrespective of whether coronary thrombi were present. Cyr61 was rapidly released after occlusion of a septal branch in HOCM patients undergoing transcoronary ablation of septal hypertrophy. Cyr61 improved risk stratification for all-cause mortality when added to the reference GRACE risk score at 30 days (C-statistic 0.88 to 0.89, P = 0.001) and 1 year (C-statistic 0.77 to 0.80, P < 0.001) comparable to high-sensitivity troponin T (30 days: 0.88 to 0.89, P < 0.001; 1 year: 0.77 to 0.79, P < 0.001). Similar results were obtained for the composite endpoint of all-cause mortality or myocardial infarction. Conversely, in a population-based case-control cohort (n = 362), Cyr61 was not associated with adverse outcome.
Cyr61 is a novel early biomarker reflecting myocardial injury that improves risk stratification in ACS patients.