Contrast agents for cardiac angiography: effects of a nonionic agent vs. a standard ionic agent.

The effects on cardiac hemodynamics and serum parameters of a standard contrast agent (sodium methylglucamine diatrizoate [Renografin 76]) were compared with the effects of a new nonionic agent (iohexol) in a double-blind study in 51 patients undergoing coronary angiography and left ventriculography. No significant alteration in measured blood parameters occurred with either contrast agent. Hemodynamic changes occurred with both, but were significantly greater with the standard Renografin than with the low-osmolality, nonionic iohexol. After left ventriculography, heart rate increased and peripheral arterial pressure fell with both agents, but less with iohexol. Following coronary artery injections, heart rate and arterial pressure decreased with both agents, but the changes were more marked and occurred earlier with the standard contrast material. It is concluded that iohexol causes less alteration in cardiac function than does the agent currently most widely used. Nonionic contrast material is likely to improve the safety of coronary angiography, particularly in those patients at greatest risk.