RESUMEN
AIMS: Comparing the nephrotoxicity of individual contrast agents is challenging, as contrast-induced acute kidney injury (CI-AKI), a widely used trial endpoint, is unable to discriminate between contrast-related and contrast-unrelated causes of renal damage. We established a quantitative method to selectively evaluate the dose-dependent nephrotoxic effect of different contrast agents. METHODS: We randomized 113 patients undergoing coronary procedures to either iodixanol 320âmg/ml or iobitridol 350âmg/ml. We calculated baseline creatinine clearance (CrCl) and postprocedural change in serum creatinine. We then calculated the regression of the individual iodine load against the creatinine maximum change [load-to-damage relationship (LDR)]. We assumed that its R estimates the predictive accuracy of contrast dose-dependent effects on renal function changes, and that the slope of the LDR characterizes the intrinsic nephrotoxicity of the contrast. We also performed a semi-quantitative evaluation of procedural complexity to assess its complementary role in postprocedural AKI. RESULTS: We found significant correlations between contrast load and creatinine changes for both iobitridol (R: 0.29; Pâ<0.0001) and iodixanol (R: 0.15; Pâ=â0.00028). The LDR slope was, however, significantly steeper for iobitridol compared with iodixanol (19.03â±â4.02 vs. 14.50â±â4.63âCr*CrCl/I; Pâ<0.001) and in diabetic compared with nondiabetic patients (24.35â±â4.96 vs. 4.59â±â3.25âCr*CrCl/I; Pâ<0.001). Adding the procedural complexity score to the contrast load significantly increased the predictive ability of the regression model for postprocedural renal function changes (Pâ<â0.02 for the R increase in overall population), suggesting a role for procedural complexity in postprocedural renal function damage. CONCLUSION: The LDR slope is a promising method to evaluate the specific contrast-related fraction of postprocedural AKI.