CHANGES IN CONTRACTILE FUNCTION WITH LOW-OSMOLAL AND ISOSMOLAL CONTRAST-MEDIA FOR CORONARY ANGIOGRAPHY

Changes in contractile function induced by modern roentgen contrast me dia (CM) were examined in isolated rat hearts. Four coronary perfusion s were undertaken in each heart with increasing volumes of each CM in order to test a wider spectrum of potential side-effects. Left ventric ular developed pressure (LVDP) and heart rate (HR) were recorded. Six commercially available or investigational CM were examined: A, Hexabri x (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 we re low-osmolal (400-940 mosm/kg H2O) CM, whereas B, C and D were essen tially 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 chang es were observed in HR. The study revealed that cardiac function was h ardly affected by CM which had the following characteristics: a low to normal osmolality (< 400 mosm/kg H2O); a low concentration of contras t 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 C M tested that may be in clinical use in coronary angiography (300-350 mg I/ml), Isovist and Visipaque induced the least changes in contracti lity.