Platelet function testing using the Multiplate analyzer after administration of aspirin in Aachen minipigs

Knowledge of platelet function in pigs and the effectiveness of antiplatelet therapy is important to ensure proper transferability from animal studies to humans. Our aim was to (1) characterize baseline platelet function of Aachen minipigs using the bedside Multiplate analyzer, (2) compare baseline platelet function with Göttingen minipigs, and (3) characterize platelet inhibition within the first 5 minutes after intravenous administration of acetylsalicylic acid (ASA). We characterized the baseline platelet function and hematological parameters in 9 Aachen minipigs. Historical data of 8 unmedicated Göttingen minipigs were used for comparison of baseline values. Platelet inhibition in Aachen minipigs was tested 1-5 minutes after intravenous administration of 500 mg ASA. Multiplate examinations included the following tests: ASPI test (to assess the effect of ASA), adenosine-diphosphate-test (ADP test) and thrombin receptor activating peptide test (TRAP test). Median values and interquartile range (IQR) of the Multiplate baseline tests in Aachen minipigs were as follows: ASPI: 39 U (IQR = 21-71), ADP: 70 U (IQR = 48-73), and TRAP: 8 U (IQR = 6-9), whereas the values in Göttingen minipigs were as follows: ASPI: 70.5 U (IQR = 60-78), ADP: 51 U (IQR = 45-66), and TRAP: 6.5 U (IQR = 4-8). ASPI values of Göttingen minipigs were significantly higher than those of Aachen minipigs (p = 0.046). Intravenous administration of ASA in Aachen minipigs resulted in significant platelet inhibition after 1 minute, which remained stable over a period of 5 minutes (p≤0.038). Aachen minipigs appeared to have a high variance in arachidonic acid-mediated platelet aggregation. In Aachen minipigs, intravenous ASA administration resulted in immediate platelet inhibition.