Variability of platelet degranulation by different contrast media.
OBJECTIVE
It has been suggested that nonionic but not ionic contrast media degranulate blood platelets when mixtures of blood and contrast media are studied by flow cytometry. This phenomenon was further assessed in the current study not only by performing whole-blood platelet flow cytometry but also by performing flowing blood platelet aggregometry. The latter is a highly sensitive measure of platelet function.


METHODS
Blood samples were collected from six normal donors and mixed with equal volumes of an ionic monomer (diatrizoate), a nonionic monomer (iohexol), an ionic dimer (ioxaglate), and a nonionic dimer (iodixanol). Samples were collected in the presence of no anticoagulant for 1 min prior to the addition of sodium citrate or in the presence of heparin (14.5 U/ml) or recombinant hirudin (60 micrograms/ml). All samples were fixed in formaldehyde within 30 min.


RESULTS
Platelet degranulation was observed with one nonionic agent (iohexol) and one ionic agent (diatrizoate). Degranulation was not seen with iodixanol or ioxaglate.


CONCLUSIONS
These findings indicate that degranulation is independent of the ionic or nonionic nature per se of contrast media. A possible explanation for this conclusion is suggested.
Grabowski
E F
EF
Massachusetts General Hospital-Harvard Medical School, Boston 02114, USA.
Jang
I K
IK
Gold
H
H
Head
C
C
Benoit
S E
SE
Michelson
A D
AD
D000925:Anticoagulants / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology; D015550:Cell Degranulation / Q000187:drug effects*; D003287:Contrast Media / Q000494:pharmacology*; D003973:Diatrizoate / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D007472:Iohexol / Q000494:pharmacology; D007485:Ioxaglic Acid / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D014283:Triiodobenzoic Acids / Q000494:pharmacology
D000925:Anticoagulants; D003287:Contrast Media; D014283:Triiodobenzoic Acids; D003973:Diatrizoate; D007472:Iohexol; C044834:iodixanol; D007485:Ioxaglic Acid