Activation of platelets by low-osmolar contrast media: differential effects of ionic and nonionic agents.
OBJECTIVE
To determine the effects of an ionic low-osmolar contrast medium (ioxaglate) and two nonionic low-osmolar contrast media (iohexol and iopamidol) on human platelet activation in vitro.


METHODS
Flow cytometry analysis subsequent to reaction with fluorescence-labeled monoclonal antibodies was used to detect antigens that appear on the platelet surface on activation.


RESULTS
Ioxaglate did not activate platelets, but evidence of platelet activation by iohexol and iopamidol was found in blood from two and three healthy volunteers, respectively, of the six volunteers studied. In addition, ioxaglate inhibited the thrombin-induced in vitro activation of platelets, whereas iohexol and iopamidol did not.


CONCLUSIONS
These findings support a tendency toward a higher frequency of thromboembolic complications with nonionic low-osmolar contrast media, although clinical trials will be needed to confirm this possible trend.
Department of Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands.
M R
MR
Hardeman
A
A
Konijnenberg
A
A
Sturk
J A
JA
Reekers
D005260:Female; D006801:Humans; D007472:Iohexol / Q000494:pharmacology*; D007479:Iopamidol / Q000494:pharmacology*; D007485:Ioxaglic Acid / Q000494:pharmacology*; D008297:Male; D009994:Osmolar Concentration; D015539:Platelet Activation / Q000187:drug effects*; D013917:Thrombin / Q000494:pharmacology
D007472:Iohexol; D013917:Thrombin; D007479:Iopamidol; D007485:Ioxaglic Acid