Effect of a low-osmolality nonionic contrast medium (iopromide) on blood platelet membrane structure and aggregation

Abstract

Nonionic contrast media (NICM) used in radiology exhibit weaker anticoagulant properties than ionic media. This study was intended to evaluate the effect of iopromide NICM upon the platelet aggregation and their membrane structure (investigated by electron paramagnetic resonance method with a spin label). Blood was collected directly from the left ventricle during coronary angiography prior to and following the application of the contrast medium. These results were compared with in vitro examinations. Based on the spectral curves parameters that reflect conformational changes in membrane proteins were determined. The iopromide-induced decrease in platelet aggregation examined in vitro with adenosine diphosphate (ADP), collagen and ristocetine was statistically significant. In vitro platelet membrane structure was modified significantly with regard to both protein conformation and the accessibility of sulfhydryl (- SH) and amino (- NH2) groups. In ex vivo studies the changes in platelet aggregation was only observed with ADP, whereas in the membrane-structure modifications were only noted regarding accessibility of - SH and - NH2 groups. We conclude that iopromide-induced platelet aggregation changes are most probably due to their membrane-structure modifications, whereas the less-pronounced contrast effect ex vivo is due to its rapid dilution in the inflowing blood. The results confirm weak antiplatelet and anticoagulant influence of NICM in vivo.