Safe ex vivo coronary angiography with isosmotic contrast agent

Plain-film coronary angiography of the cardiac explant on the operating table should be considered when conventional cardiac catheterization is desired but unavailable. We compared the effects of three contrast solutions on cold-preserved, isolated guinea pig hearts. Hearts were excised, perfused for 30 minutes, and arrested with Plegisol solution at 7 degree C. Twenty minutes after arrest, experimental hearts were perfused with one of three solutions: hyperosmolar Hexabrix solution (n = 6), hyperosmolar Renografin-76 solution (n = 6), or diluted, isosmotic Omnipaque solution (n = 8). The hearts were flushed with cold Plegisol solution 5 minutes later. Control hearts received no contrast during arrest (n = 9). The hearts were reperfused after 1 hour of arrest, and coronary blood flow (in millimeters per minute), left ventricular developed pressure (in millimeters of mercury), and rate of developed pressure (in millimeters of mercury per second) were measured. Endothelium-dependent smooth muscle relaxation to bradykinin administration and endothelium-independent relaxation to sodium nitroprusside administration were also assessed. No significant difference in myocardial or endothelial function was noted between control hearts and hearts perfused with Omnipaque solution. Hearts perfused with Renografin solution or Hexabrix solution, however, were found to have significantly impaired endothelial and myocardial function. We conclude that an isosmotic contrast solution should be used for ex vivo coronary angiography in cold-preserved hearts to avoid impairment of endothelial and myocardial function.