Cardiovascular effects of contrast agents.

Iodinated radiologic contrast agents should, ideally, passively provide radiographic contrast in blood vessels and soft tissues but have no effects on physiology, hematology or biochemistry. In practice, no such agent exists although the nonionics most closely approach the ideal. All agents have a bewildering variety of effects on the cardiovascular system, which, in turn, engender a variety of neurogenic and humoral responses. The mechanisms underpinning these many phenomena appear to involve hyperosmolality, molecular structure, ionic content and balance. This review presents the current state of knowledge of these effects and their mechanisms, with emphasis on the differences between conventional ionic and more inert nonionic agents.