We injected iopamidol, meglumine diatrizoate, saline, and various mannitol solutions (5,10, 20 weight/weight) into the right common carotid artery of anesthetized rabbits. To determine the cardiovascular responses to these injections, we measured and analyzed the changes in mean aortic pressure, mean carotid blood flow and its duration, volume of carotid blood flow, and resistance of carotid vascular bed. The volume change of carotid blood flow was calculated by the integration of blood flow.
Mean aortic pressure decreased transiently and then returned to control levels within 10–20 seconds from the beginning of the injection for all agents. Carotid blood flow increased and carotid vascular bed resistance decreased transiently, returning to control levels within 10–20 seconds after the injection; the duration was found to be influenced by the agent's osmolality. Therefore, volume change was analyzed because it is a concurrent index of flow and duration.
The cardiovascular response to each test agent was proportional to the agent's osmolality. Pearson's correlation coefficient was the highest between the volume change (increase) of carotid blood flow and the agent's osmolality (r = .8091). Increased volume of carotid blood flow appears to be a useful index for estimating the vasodilatory effects of contrast media.
Iopamidol caused less severe cardiovascular responses than meglumine diatrizoate in experimental common carotid angiography; however, the responses were greater than for saline.
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