Iohexol, ioxaglate and iopamidol in coronary angiography. A double-blind comparative study of 300 patients.

A randomized, double-blind study was carried out in 300 consecutive coronary angiography examinations to investigate the clinical safety of three low osmolar contrast media, iohexol 300, ioxaglate 320 and iopamidol 300, and the electrocardiographic changes that occurred with them. The ECG from electrode V5/V6 or AVF and intra-arterial pressure were monitored continuously, and recorded before and after the first contrast injections into the left and right coronary arteries. Of the variables tested, no statistically significant changes occurred in systolic arterial pressure, PR interval or ventricular extrasystole. The QT interval increased in the ioxaglate group (p = 0.001). Heart rate decreased in all groups, but slightly less in the ioxaglate group than in the iopamidol group (p = 0.02). The ST segment depression (mean 0.67m) was more marked in the ioxaglate group than in the other treatment groups (p = 0.0001) during right coronary angiography. The same characteristics, but less marked, were observed during left coronary angiography, the ioxaglate group (mean 0.251mm) differing from the iopamidol group (mean 0.050mm) (p = 0.04). No significant difference in severe adverse reactions were detected between these groups (ioxaglate 1, iopamidol 1). Ioxaglate produced mild side effects (nausea, vomitus, urticaria) in 16% of the patients, the other two contrast agents producing side effects in 1%.