Evaluation of angiographic contrast media and platelet function with impedance aggregometry and the PFA-100 (TM) 'platelet function analyser'

Background: Angiographic contrast media are used in baboon angioplasty and may influence thrombotic complications of the procedure. We studied the eff ect of different media on platelet aggregation in whole blood using impedan ce aggregometry and the PFA-100 'platelet function analyser' (Dade, USA). M ethods: Venous blood samples from 18 healthy volunteers were split into fou r aliquots and mixed with 10% normal saline control, non-ionic medium (iohe xol), low-molecular weight ionic medium (ioxaglate) and high-molecular weig ht ionic medium (diatrizoate). Samples were studied with impedance aggregom etry and the PFA-100, Results: All media caused significant inhibition of a ggregation compared with control with both methods (P<0.001). Antiplatelet potency was greatest with diatrizoate, intermediate with ioxaglate and leas t with iohexol with both methods (P<0.01), Electron microscopy of the PFA-1 00 membrane demonstrated occlusion of the experimental aperture with platel et thrombus in the control. Inhibition of platelet thrombus was seen with a ll media, greatest with diatrizoate, intermediate with ioxaglate and least with iohexol, Conclusions: The media studied significantly inhibited platel et aggregation in vitro and potency was greater with ionic than non-ionic m edia. These methods use a combination of shear and chemical agonist with wh ole blood and may reproduce in vivo arterial conditions better than other t echniques.