Influencing factors of ADP-induced, epinephrine-induced and ristomycin-induced platelet aggregation in dogs.

Functional defects of platelets are often studied by in-vitro aggregation tests with chemical compounds such as ADP, epinephrine and ristomycin (ristocetin). The aim of the present work was to investigate the effect of some diseases and that of nonsteroidal anti-inflammatory drug treatment on platelet aggregation in dogs. The examination had been carried out on 115 dogs by a Carat TX4 optical aggregometer (Entec GmbH, Ilmenau, Germany) first used in veterinary practice. The dogs were divided in three groups: healthy (control) dogs (n = 43), diseased dogs with normal haemostasis profile (n = 44), and dogs suffering from arthropathies with normal haemostasis profile treated with the nonsteroidal anti-inflammatory drugs ketoprofen or carprofen (n = 21). Following establishment of normal platelet aggregation curves in healthy dogs we found that some diseases such as diabetes mellitus, Cushing's disease, mastocytoma and lymphoma increased or decreased the aggregation maximum of platelets or caused changes in the feature of the aggregation curve. Carprofen treatment had no effect on platelet aggregation while ketoprofen decreased the aggregation maximum. These results showed that Carat TX4 aggregometer proved a useful instrument in studying platelet aggregation in platelet-rich plasma of dogs. For clinical pathologists it is important to know that the effects of some diseases and nonsteroidal anti-inflammatory drug treatments have to be taken into account when in-vitro platelet aggregation is evaluated. Based on our results and on those of other studies, we think standardization in aggregation methodology is highly recommended in veterinary laboratories.