Contrast medium volume to creatinine clearance ratio: a predictor of contrast-induced nephropathy in the first 72 hours following percutaneous coronary intervention.

OBJECTIVES

To investigate the predictive value of the contrast media volume to creatinine clearance (V/CrCl) ratio for the risk of contrast-induced nephropathy (CIN) (i.e., within 48-72 hr) and to determine a relatively safe V/CrCl cut-off value to avoid CIN in patients following percutaneous coronary intervention (PCI).

BACKGROUND

The V/CrCl ratio is a pharmacokinetic risk factor for an early abnormal increase in serum creatinine (i.e., within 24 hr) after PCI.

METHODS

V/CrCl ratios were obtained from 1,140 consecutive consenting patients after unselective PCI. Receiver-operator characteristic (ROC) curves were used to identify the optimal sensitivity for the observed range of V/CrCl. The predictive value of V/CrCl for the risk of CIN was assessed using multivariate logistic regression.

RESULTS

Fifty-five (4.8%) patients out of 1,140 developed CIN. There was a significant association between higher V/CrCl ratio values and risk of CIN in the overall population: 1.4%, 1.4%, 5.7%, and 10.9% for quartile 1 (Q1) of the V/CrCl value (<1.56, n = 283), Q2 (1.56-2.27, n = 289), Q3 (2.28-3.42, n = 282), and Q4 (>3.42, n = 285) of contrast, respectively (P < 0.001). ROC curve analysis indicated that a V/CrCl ratio of 2.62 was a fair discriminator for CIN (C-statistic 0.73). After adjusting for other known predictors of CIN, V/CrCl ratios > 2.62 remained significantly associated with CIN (odds ratio: 2.20; 95% confidence interval: 1.00-4.81, P < 0.05).

CONCLUSION

A V/CrCl ratio > 2.62 was a significant and independent predictor of CIN after PCI in unselected patients.