Changes in Contractile Function with Low-Osmolal and Isosmolal Contrast Media for Coronary Angiography

Changes in contractile function induced by modern roentgen contrast media (CM) were examined in isolated rat hearts. Four coronary perfusions were undertaken in each heart with increasing volumes of each CM in order to test a wider spectrum of potential side-effects. Left ventricular developed pressure (LVDP) and heart rate (HR) were recorded. Six commercially available or investigational CM were examined: A, Hexabrix (ioxaglate 320 mg I/ml, Na 146 mM); B, Isovist (iotrolan 300 mg I/ml, Na 6 mM); C, Visipaque (iodixanol 320 mg I/ml, Na 19 mM, Ca 0.3 mM); D, “Iodixanol high Ca-Mg” (iodixanol 320 mg I/ml, Na 19 mM, Ca 1.2 mM, Mg 0.6 mM); E, “Iohexol I 350” (iohexol 350 mg I/ml, Na 28 mM); and F, “Iohexol I 150” (iohexol 150 mg I/ml Na 28 mM). A, E and F were low-osmolal (400–940 mosm/kg H₂O) CM, whereas B, C and D were essentially isosmolal.

Contractile changes (transient LVDP depression) was volume-dependent. Maximal values for LVDP depression were: “Iohexol I 150” 11–22%< Isovist 13–45% and Visipaque 18–45%<“Iodixanol high Ca-Mg” 14–62%<“Iohexol I 350” 40–76%<Hexabrix 92–96%. No changes were observed in HR.

The study revealed that cardiac function was hardly affected by CM which had the following characteristics: a low to normal osmolality (<400 mosm/kg H₂O); a low concentration of contrast agent (150 mg I/ml); and an overall content of ions (Na 6-28 mM, Ca 0–0.3 mM) complying well with myocardial ratios of Na and Ca. Of the CM tested that may be in clinical use in coronary angiography (300–350 mg I/ml), Isovist and Visipaque induced the least changes in contractility.