Contrast agents for cardiac catheterization: conceptions and misconceptions.

Ionic and nonionic contrast materials are similarly efficacious in providing excellent images with minimal risk to the patient. In comparison with ionic media, the nonionic agents produce minor alterations in intracardiac and peripheral pressures as well as in electrocardiographic intervals and morphology. In addition, nonionic media are less often associated with undesirable symptoms, such as flushing and vomiting. At the same time, ionic and nonionic media are accompanied by a similar incidence of nephrotoxicity, serious arrhythmias, and death. Finally, nonionic contrast material is substantially more expensive than ionic media. In light of this marked difference in cost, one could argue that nonionic media should be reserved for "high-risk" patients, that is, those with a history of a serious adverse reaction to ionic contrast media and those in whom contrast-induced hypotension would be particularly deleterious.