Abstract 5012: Cystatin C and Cardiovascular Mortality in Patients with Coronary Artery Disease and Maintained Renal Function
Chronic kidney disease is associated with an increased risk of cardiovascular disease. Cystatin C is a promising marker to reliably detect renal function. The role of cystatin C in patients with coronary artery disease and maintained renal function is less well established. In 2082 consecutive patients with documented coronary artery disease (CAD) (1267 with stable angina (SAP) and 815 with acute coronary syndrome (ACS)) baseline concentrations of cystatin C were measured if MDRD estimated glomerular filtration rate (GFR) was >30ml/min/1.73m2. During a median follow-up of 3.65 years cardiovascular mortality was documented (n=90). The median age of the study cohort was 63 years, 78.0% were of male gender. Age, sex, body mass index (BMI), and current smoking were predictors of cystatin C baseline concentration. GFR showed a strong negative association and the biomarkers Nt-proBNP and CRP were positively related to cystatin C measurements. Kaplan-Meier survival analysis showed a stepwise decrease in cardiovascular survival across quartiles of cystatin C baseline concentration (p log rank<0.0005). A similar pattern was observed in the subgroups of patients with SAP and ACS (p log rank<0.0005). A increase in cystatin C concentration by one quartile was associated with a 2.31-fold risk of future cardiovascular death (95% confidence interval 1.87–2.86, p<0.0005). A similar strength of association was seen in the subgroups. This risk association remained robust after adjustment for potential confounders. The addition of cystatin C to a basic model of cardiovascular risk factors increased the c-index from 0.713 (95% bootstrap confidence interval 0.658 – 0.785) to 0.762 (0.705– 0.827), and this strength was similar to the increase achieved by adding Nt-proBNP to the basic model (0.764, 0.724 – 0.833) while GFR only increased the c-index to 0.729 (0.676 – 0.799). Cystatin C is a potent predictor of cardiovascular mortality in patients with CAD and normal kidney function or mild renal impairment.