Effects of nonionic contrast media on platelet aggregation - Assessment byparticle counting with laser-light scattering

Intravascular radiographic contrast media used in angiography, particularly nonionic contrast media, may cause activation of platelets. This study M a s designed to determine which properties: of nonionic contrast media were p otentially responsible for this action. Platelet aggregation after adenosin e diphosphate stimulation was studied in the platelet rich plasma obtained from 37 patients who underwent left ventriculography using the highly sensi tive method of particle counting with laser-light scattering. Platelet acti vation by contrast media M as studied in the platelet rich plasma from heal thy volunteers using flow cytometric analysis to detect platelet degranulat ion as P-selectin expression. There was a significant decrease in platelet aggregation in patients injected with ioxilan or iomeprol compared with pat ients injected with iohexol. There was a significant increase in P-selectin expression with the three groups of contrast media compared to control. Th e platelet activation with ioxilan or iomeprol was significantly less compa red to the activation with iohexol. The comparison showed that previous gen eralization regarding platelet activation by nonionic contrast media might not be valid. It is presumed that the higher osmolality of iohexol may cont ribute to the increase in platelet aggregation and activation.