Factors influencing the activation of platelets by nonionic contrast medium.
OBJECTIVE
To determine why nonionic, low-osmolality contrast media (LOCM) at high concentrations (> 30%) induce almost immediate platelet activation and to explore preventive measures.


METHODS
Nonionic LOCM, when added to blood, activates platelets, raises the osmolality, and lowers the ionic strength. To clarify the mechanisms involved, platelet activation was studied in sodium chloride-sucrose solutions of varying osmolalities and varying ionic strengths. Several salts and Iloprost were evaluated as potential inhibitors of platelet activation.


RESULTS
Platelets are activated by both osmolality and ionic strength changes. The salts most inhibitory to platelet activation were magnesium sulfate and sodium citrate. Iloprost lowered platelet activation to control levels at 4.3 ng/mL of nonionic LOCM and completely eliminated it at 8.6 ng/mL.


CONCLUSIONS
Three-quarters of nonionic LOCM-induced platelet activation appeared to be due to increased osmolality-the remainder to the decrease in ionic strength. Magnesium sulfate and Iloprost are potent inhibitors of this type of platelet activation.
Hay
K L
KL
Department of Pathology, Loma Linda University Medical Center, CA, USA.
Bull
B S
BS
D000328:Adult; D003287:Contrast Media / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D015539:Platelet Activation / Q000187:drug effects*; D014283:Triiodobenzoic Acids / Q000633:toxicity*
D003287:Contrast Media; D014283:Triiodobenzoic Acids; C054871:ioversol