Nephrotoxicity of high and low osmolar contrast media: case control studies following digital subtraction angiography in potential risk patients.

The urinary excretion of kidney-specific marker proteins before and 120 hours after intravenous injection of either high- or low-osmolar contrast media (CM; diatrizoate, iopamidol 370) was monitored in patients after digital vascular imaging. Inclusion criteria for the randomized clinical study in a total of 40 patients (15 women, 25 men; mean age, 64.5 years) were at least 50 years of age or diabetes mellitus with normal creatinine concentration in serum. Compared with the control period, the elimination of tubular indicator enzymes alanine aminopeptidase, gamma-glutamyltranspeptidase, alkaline phosphatase, as well as of glomerular localized angiotensinase A was significantly higher in all patients after injection of the CM. The most significant differences were observed after 48 hours. In contrast, lysosomal N-acetyl-beta-D-glucosaminidase activity in urine specimens reacted less clearly and appears to be a less sensitive parameter in assessing CM nephrotoxicity. Elimination of brush border as well as of glomerular marker proteins was significantly lower after intravenous injection of low-osmolar CM iopamidol 370 (832 mOsm/kg) than after meglumine diatrizoate 76 (2100 mOsm/kg). In all 40 patients a significant decrease in creatinine clearance was observed; however, patients receiving diatrizoate had a significant decrease in creatinine clearance (period 0 versus 24 to 48 hours after CM), whereas patients after administration of iopamidol had not. No difference was found between creatinine clearance after 48 hours of CM injection within both groups of CM. Due to noninvasive parameters of kidney damage nonionic, low-osmolar CM are less nephrotoxic in potential risk patients, and should be preferred to conventional CM.