Effects of iohexol and metrizoate on myocardial blood flow and metabolism.

In 10 patients coronary sinus blood flow (CSBF) was measured during and after injection of iohexol and meglumine-Na-Ca metrizoate in the left coronary artery. Oxygen saturation, lactate concentration and hematocrit were determined in the aorta and coronary sinus before and after a second injection of the two contrast media. The increase in CSBF was significantly more marked and sustained after injection of metrizoate than after iohexol and myocardial arterio-venous oxygen difference was significantly lower. Myocardial oxygen consumption and lactate metabolism were not adversely affected by any of the contrast media. The fall in hematocrit in coronary sinus blood was significantly greater after metrizoate.