Effect of low-osmolality contrast media on red cell filterability.

The effects of low-osmolality contrast media (CM) on red blood cell (RBC) filterability were investigated using a recently developed nickel mesh filtration method. The conventional hypertonic CM iothalamate, low-osmolality iohexol, and the recently synthesized iomeprol were studied. Among them, the osmolality of iomeprol was the lowest. The impact of CM osmolality, viscosity, and iodine content on the RBC filterability was analyzed. Under equal iodine content or viscosity condition, the filterability order of RBCs suspended in CM was iomeprol > iohexol >> iothalamate, because of the osmolality of CM. Iomeprol caused small echinocytic changes but these had a negligible influence on RBC filterability. In conclusion, the osmotic effect of CM on RBC filterability is more predominant than the other CM effects, and iomeprol is the preferred CM for RBC filterability.