Figure 1

Acetylsalicylic acid could not inhibit platelet aggregation in vivo and in vitro (Groups 1a–c). A–B: Acetylsalicylic acid (ASA) in a concentration of 500 mg bid given per os (p.o.) in Group 1a (A) and intravenously (i.v.) in Group 1b (B) had no significant effect on arachidonic acid induced platelet final aggregation (AA-FA) in the light transmission aggregometry (LTA) between baseline and days 1, 4 and 7, respectively (one-way repeated measures ANOVA). Values did not decline below the cut-off value at any time point (red line, 60.6%). Platelet aggregation was induced by 10.93 mM arachidonic acid. C: In vitro acetylsalicylic acid failed to inhibit arachidonic acid induced platelet final aggregation of sheep platelet rich plasma. The platelet aggregation in human platelet rich plasma was inhibited with acetylsalicylic acid in a concentration of 1 mg/mL in LTA. However, no significant change in sheep platelet final aggregation could be detected after addition of 1 mg/mL or 10 mg/mL acetylsalicylic acid compared to baseline or control (Friedman Test). Values did not decline below the cut-off value at any time point (red line, 60.6%). Platelet aggregation was induced by 10.93 mM arachidonic acid. As control, aqua ad injectabilia instead of acetylsalicylic acid solution was used.