Effects of ionic and nonionic contrast media on coronary diameter and blood flow in chronically instrumented dogs

Abstract

The effects of intracoronary administration of ionic and nonionic contrast media on coronary circulation were studied in 14 chronically instrumented dogs. A pair of 10 MHz piezoelectric crystals and an electromagnetic flow probe were placed on the left circumflex coronary artery, under sterile conditions, to measure the epicardial coronary diameter and coronary blood flow, respectively. A polyethylene tube for drug infusion was inserted into the circumflex coronary artery proximal to the sonomicrometers. In the conscious dogs ( n = 8), iopamidol, 2 ml and 5 ml, increased the coronary diameter by 64 ± 19 μm and 66 ± 19 μm and coronary blood flow by 35 ± 10% and 61 ± 18%, respectively ( p < 0.01 vs control level). Meglumine diatrizoate, 2 ml and 5 ml, increased coronary diameter by 102 ± 20 μm and 114 ± 18 μm and coronary blood flow by 87 ± 32% and 107 ± 26%, respectively ( p < 0.01 vs control level). In the anesthetized dogs ( n = 6), a bolus intracoronary injection of 5 ml iopamidol and meglumine diatrizoate within a few seconds increased the coronary diameter by 103 ± 23 μm and 164 ± 39 μm ( p < 0.05) and increased the coronary blood flow by 126 ± 33% and 180 ± 40% ( p < 0.05), respectively. Balloon denudation of the endothelium was performed in six anesthetized dogs. The increases in coronary diameter and coronary blood flow after a bolus injection of contrast medium remained the same after the denudation. Thus application of iopamidol seems to be more suitable than meglumine diatrizoate for quantitative coronary angiography because of the milder and more transient effects on coronary circulation.