Influence of radiographic contrast agents on quantitative coronary angiography

Purpose: Quantitative angiographic studies on the vasomotility of epicardial coronary arteries are gaining increasing relevance. We investigated whether radiographic contrast agents might influence coronary vasomotor tone and thereby the results of such studies. Methods: Coronary angiograms were taken in 12 patients with coronary artery disease at intervals of 5, 3, 2, and 1 min with the low-osmolar, nonionic contrast agent iopamidol 300, and were repeated at identical intervals with the high-osmolar, ionic agent diatrizoate 76%. Results: Quantitative cine film analysis demonstrated no significant diameter changes in angiographically normal and stenotic coronary arteries with iopamidol. With diatrizoate, however, normal segments were dilated 2% +/- 2% (p < 0.01) after 2 min and 10% +/- 3% after the 1 min interval (p < 0.001). Stenoses showed no uniform responses to diatrizoate. Conclusion: Low-osmolar, nonionic contrast agents should be preferred for quantitative angiographic studies on epicardial coronary vasomotility. When using ionic contrast agents, injection intervals of at least 3 min are required.