LOW-OSMOLALITY CONTRAST-MEDIA AND THE RISK OF CONTRAST-ASSOCIATED NEPHROTOXICITY

OBJECTIVES. The authors review clinical data, including those from the recent Iohexol Cooperative Group trial, regarding the nephrotoxic pot ential of low-osmolar versus high-osmolar contrast media. The clinical characteristics and postulated mechanisms of contrast-associated neph rotoxicity are also considered. METHODs. The principal strategy for id entifying relevant articles was to search the MEDLINE database using t he MeSH heading ''contrast media nephrotoxicity.'' Articles from 1966 through 1992 that were considered included original research papers as well as reviews. Those articles selected for detailed review document ed original research pertaining to use of low-osmolar or high-osmolar agents. Selected abstracts for pertinent society meetings were also us ed. No attempt was made to be complete in describing the field. Rather , specific articles that selectively address the question of nephrotox icity related to the osmolar content of contrast media were used for d iscussion. RESULTS AND CONCLUSIONS. In-vitro and animal studies indica te that renal changes possibly involved in the pathogenesis of contras t-associated nephrotoxicity seem to be ameliorated with low-osmolar co ntrast media, compared with high-osmolar agents. Several recent clinic al trials, as well as a meta-analysis combining 24 randomized studies, suggest that the risk of contrast-associated nephrotoxicity is simila rly low with high-osmolar and low-osmolar agents among otherwise stabl e patients with normal renal function, but that low-osmolar contrast i s less nephrotoxic than media with high osmolality in patients with pr e-existing renal insufficiency.