CARDIAC HEMODYNAMIC-EFFECTS OF IODIXANOL, IOPAMIDOL, AND IOXAGLATE FOLLOWING LEFT CORONARY INJECTIONS IN ANESTHETIZED DOGS

Rationale and Objectives. Iodixanol, a dimeric, nonionic X-ray contras t medium, has been formulated at 320 mg iodine per milliliter and supp lemented with Na+, Ca2+, and Cl- to produce an osmolality that approxi mates that of plasma. We compared the effects of left main coronary ar tery injections of iodixanol, ioxaglate, and iopamidol on cardiac mech anical function in dogs. Methods. Six mixed-breed dogs were anesthetiz ed and prepared for recordings for electrocardiogram, aortic and left ventricular pressures, and the first derivative of left ventricular pr essure, dP/dt. The test solutions and saline were injected into the le ft coronary artery in a randomized order. The series of four injection s were repeated three times in each animal for a total of 12 injection s per dog. Results. Iodixanol caused significantly lower (p < .05) red uction in peak left ventricular pressure (-1.7 +/- 0.9% vs -0.7 +/- 2. 0%), in diastolic aortic pressure (-1.3 +/- 1.1% vs -9 +/- 1.3%), and in left ventricular dP/dt (0.3 +/- 1.3% vs -13.2 +/- 2.4%) than did io xaglate. Iodixanol also produced smaller cardiovascular effects than d id iopamidol, but the differences were not statistically significant. Injections of both iopamidol and ioxaglate caused significant decrease s from baseline parameter values; however, the changes with iodixanol were not significant. Conclusion. The isotonic formulation of iodixano l caused smaller cardiovascular hemodynamic effects than did iopamidol and ioxaglate and may offer increased safety in patients with severe cardiac disease.