Cystatin C is associated with an increased coronary atherosclerotic burden and a stable plaque phenotype in patients with ischemic heart disease and normal glomerular filtration rate

OBJECTIVE: Cystatin C (Cys-C) is an accurate marker of renal function. Recent studies have shown that serum Cys-C levels predict the risk of cardiovascular events. The causes of this association, however, are largely unknown. METHODS AND RESULTS: Seventy consecutive patients (age 62+/-12, male sex 87%) undergoing coronary angiography because of typical chest pain and found to have coronary artery disease were included in the present study. Patients with abnormal creatinine-derived glomerular filtration rate (<90ml/min/1.73m(2)) were excluded in order to avoid the well-known effect of overt renal insufficiency on coronary atherosclerosis. Coronary angiography was evaluated by two expert angiographers who assessed disease severity and extent according to the Sullivan's score and lesion morphology. In all patients, Cys-C and C-Reactive Protein (CRP) serum levels were measured on admission. Multivariable analysis was performed to assess independent predictors of angiographic measures. Diabetes was the only predictor of disease severity (p=0.005), while male sex (p=0.03), hypercholesterolemia (p=0.04), diabetes (p<0.0001) and Cys-C (p<0.0001) were independent predictors of disease extent. Independent predictors of smooth lesions were diabetes (p<0.001) and Cys-C (p=0.005). No correlation was found between Cys-C and CRP serum levels (p=0.6). CONCLUSION: Cys-C is associated with coronary atherosclerosis extent and a smooth lesion morphology. The long-term prognostic role of Cys-C might be accounted for by a greater atherosclerotic burden, a necessary substrate for plaque destabilization.