Summary
We studied the effect of an ionic high osmolar contrast medium (Ioxitalamate), an
ionic low osmolar contrast medium (Ioxaglate) and various nonionic low osmolar contrast
media (Iopamidol, Iopromide and Iohexol) on thrombus growth in a rabbit jugular vein
thrombosis model. Thrombus growth was determined by the accretion of 125I-labeled fibrinogen onto autologous preformed thrombi in rabbit jugular veins at
various time-intervals from 15 min up to 10 h after infusion of the study solution.
The ionic low osmolar contrast medium markedly inhibited thrombus growth whereas all
nonionic low osmolar contrast media promoted thrombus growth. The ionic high osmolar
contrast medium inhibited thrombus growth, but less than the ionic low osmolar contrast
medium. Within the group of nonionic contrast media, the Iopamidol associated promotion
of thrombus growth was significantly higher than the Iopromide or Iohexol associated
effects. The simultaneous administration of the apparently most potent thrombus growth
promoting contrast medium (i.e. Iopamidol) and heparin resulted in complete abolishment
of the increase in thrombus growth.
These results support the claims of prothrombotic properties of nonionic as compared
to ionic contrast media and could explain the clinically encountered thromboembolic
complications after the use of nonionic low osmolar contrast media.