Variable effects of radiological contrast media on thrombus growth in a rabbit jugular vein thrombosis model.

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.