Comparison of serum creatinine and cystatin C for early diagnosis of contrast-induced nephropathy after coronary angiography and interventions.

BACKGROUND: The diagnostic accuracy of serum creatinine and cystatin C (Cys) as early predictors of contrast-induced nephropathy (CIN) has been debated. We investigated the diagnostic sensitivities, diagnostic specificities, and variations from baseline for serum creatinine and Cys in CIN. METHODS: We prospectively evaluated 166 patients at risk for CIN at baseline, and at 12, 24, and 48 h after exposure to contrast media. CIN occurred in 30 patients (18%). Changes (Δ) compared to baseline in serum creatinine and Cys were evaluated at the predefined time points. ROC curve analysis was performed for the Δ 12-h basal serum creatinine and Cys. RESULTS: The Δ serum creatinine at 12 h from baseline was the earliest predictor of CIN [area under the ROC curve (AUC) = 0.80; P < 0.001]. The Δ serum creatinine 15% variation [0.15 mg/dL (13.2 µmol/L)] yielded 43% diagnostic sensitivity and 93% diagnostic specificity. The ΔCys at 12 h from baseline performed significantly worse than serum creatinine (AUC = 0.48; P = 0.74). CONCLUSIONS: Variations from the serum creatinine baseline offer better diagnostic accuracy for predicting CIN at an earlier stage than similar variations in Cys. An additional diagnostic value of Cys over the determination of serum creatinine in the setting of CIN was not observed.

Early creatinine shifts predict contrast-induced nephropathy and persistent renal damage after angiography.

PURPOSE: The purpose of this study was to evaluate incidence and predictors of contrast-induced nephropathy after coronary angiography and interventions, and to assess renal function at 30 days. The prognostic value of any early shift of serum creatinine compared with baseline was investigated; such measurement, being a delta, is largely independent of creatinine variations. METHODS: There were 216 patients at risk for contrast-induced nephropathy prospectively evaluated at baseline and at 12, 24, and 48 hours after exposure to contrast media, and 190 (88%) evaluated 1 month after discharge. RESULTS: Contrast-induced nephropathy occurred in 39 patients (18%), and 30-day renal damage was detected in 15 (7%). Contrast media/kg volume predicted contrast-induced nephropathy (P=.002), and percentage change of creatinine 12 hours from baseline was significantly higher in patients with nephropathy (P <.001). At multivariate analysis, percentage change of creatinine 12 hour-basal was the best predictor of nephropathy (P <.001). A 5% increase of its value yielded 75% sensitivity and 72% specificity (area under the curve 0.80; odds ratio 7.37; 95% confidence interval, 3.34-16.23) for early contrast-induced nephropathy detection. Furthermore, it strongly correlated with the development of renal impairment at 30 days (P=.002; sensitivity 87%, specificity 70%; area under the curve 0.85; odds ratio 13.29; 95% confidence interval, 2.91-60.64). CONCLUSION: Minimal elevations of serum creatinine at 12 hours are highly predictive of contrast-induced nephropathy and 30-day renal damage after exposure to contrast media.