Diagnostic accuracy of serum cystatin C for early recognition of contrast induced nephropathy in Western Indians undergoing cardiac catheterization.

AIMS: We aimed to compare the diagnostic efficacy of serum cystatin C (sCyC) for contrast induced nephropathy (CIN) in Western Indians undergoing cardiac catheterization. We also aimed to propose a clinically applicable cut-off of sCyC for early identification of CIN in this ethnic group.

METHODS: In this prospective study, 253 patients undergoing coronary angiography and/or percutaneous coronary intervention were enrolled. The demographic and risk factor details, levels of sCr at baseline, 24 and 48h after the procedure, whereas baseline and 24h levels of sCyC were noted. Increase of 0.5mg/dl or ≥25% from baseline sCr was used to define CIN. Optimum cut off of sCyC for CIN diagnosis was obtained using Receiver Operating Characteristic (ROC) curve analysis.

RESULTS: After 48h of contrast media (CM) exposure, the incidence of CIN was 12.25% (31 patients) according to sCr definition, where only 3.9% (10 patients) had sCr rise in 24h. Overall significant (p<0.0001) rise in mean levels of sCr (48h) and sCyC (24h) was observed in CIN patients. However, the mean sCr rise at 24h was non-significant. The optimum cut off of sCyC for diagnosing CIN was found to be a rise of ≥10% from baseline (AUC - 0.901; sensitivity - 100%, specificity - 77.89%). According to sCyC, 94 (37.15%) patients had CIN.

CONCLUSION: We may conclude that a rise of ≥10% in sCyC at 24h could be used as a reliable marker for identification of CIN in western Indians undergoing cardiac catheterization.