Abstract
Radio-opaque contrast media interfered with the normal process of fibrin and plasma clot formation. The morphologic changes included a decrease of the fibrin fiber diameter and an increase of protein aggregates. These appeared amorphous in the light microscope and showed a linear relationship with the concentration of contrast agents in the reaction mixture. Above a threshold concentration, which was different for each contrast media, no clot formed. With increasing concentrations of contrast medium between 3.5 x 10-3M and 2.0 x 10-2M, the optical density of the clots decreased rapidly while the incorporation of fibrin monomers into the polymer structure of the clots stayed within normal limits. This indicated that the spatial arrangements of the clots was altered. Electron micrographs confirmed that the fibrin fibers were reduced by 70 per cent to 90 per cent of the control fiber diameter in the presence of 6.1 x 10-2M sodium diatrizoate. The fibrin stabilizing enzyme (FSF, LLF or Factor XIII) catalyzed covalent cross links despite the structural changes in the clot.
