Significance of cystatin C for early diagnosis of contrast-induced nephropathy in Iraqi patients undergoing coronary angiography

Background: Contrast-induced nephropathy (CIN) has been traditionally defined as an increase in serum creatinine (sCr) after contrast media (CM) exposure. It is generally a transient and reversible form of acute renal failure. Objectives: The objective was to compare changes in serum creatinine and serum cystatin C (sCys C) in patients undergoing CM administration during coronary angiography (CAG) and/or intervention, and whether these changes are a reliable index for early identification of CIN. Materials and Methods: In this prospective study, 50 patients were included, 9 of them were omitted, and remaining 41 patients undergoing CAG and/or intervention. sCr, serum urea, sCys C, and estimated glomerular filtration rate (eGFR) were evaluated at baseline as well as 24 h after exposure to CM. Results: Forty one patients, six of them develop CIN (CIN group) and the remainder 35 not develop CIN (non-CIN group). Clinical parameters showed no significant association between CIN group and non-CIN group except in diabetes mellitus. As comparing patients before and after catheterization, the CIN group showed increase in sCr and serum urea, while remain nearly the same for sCys C, and obvious decrease for eGFR1 and eGFR2, in addition there is significant association for sCr, eGFR1, and eGFR2. In the non-CIN group, only the serum urea showed significant difference. Conclusion: The concentration change of sCr is significantly superior to cystatin C as an early biomarker in the CIN detection. An absolute increase of the concentration of sCr is highly sensitive and specific for the CIN in comparing to cystatin C