Radiology, Vol 156, 311-313, Copyright © 1985 by Radiological Society of North America
Inhibition of platelet function by contrast media: iopamidol and ioxaglate versus iothalamate. Work in progress
AK Rao, VM Rao, J Willis, C Beckett and RM Steiner
The effects of an ionic contrast agent, meglumine iothalamate (Conray- 60),
and two newer low-osmolality radiographic contrast media, sodium meglumine
ioxaglate (Hexabrix) and iopamidol (B-15,000), on platelet aggregation and
secretion responses were studied. All three agents inhibited platelet
responses during stimulation with adenosine diphosphate (ADP), epinephrine,
and collagen. Platelet function was inhibited by iothalamate at
concentrations of 11 mg iodine/ml and above, and by the newer agents at
concentrations above 30 mg iodine/ml. Addition of exogenous calcium
decreased the iothalamate-induced inhibition of aggregation but did not
improve dense granule secretion. There was no consistent effect of
exogenous calcium on platelet inhibition by iopamidol and ioxaglate. These
studies indicate that the newer agents inhibit platelet function less than
iothalamate does, and that chelation of Ca2+ may not be the major mechanism
of platelet inhibition by contrast agents.
