Thromboelastographic platelet mapping in dogs with complicated Babesia rossi infection.

Abstract

BACKGROUND: Dogs with Babesia rossi infection display a normocoagulable thromboelastogram, despite being markedly thrombocytopenic, which is purportedly due to large-scale platelet activation. Thromboelastographic platelet mapping (TEG-PM) evaluates individual contributions of thrombin, fibrinogen, and platelets to clot formation, and may elucidate some of the pathomechanisms of thrombocytopenia-associated hemostatic alterations. OBJECTIVE: This study investigated potential differences in TEG-PM variables in dogs with complicated B&#xa0;rossi infection compared with healthy controls, and whether these variables correlated with platelet activation indices. METHODS: The maximum amplitude (MA) following thrombin generation (MA) was determined using kaolin-activated TEG. The TEG-PM variables included MA following the addition of platelet agonists arachidonic acid (MA) and adenosine diphosphate (MA), and MA due to fibrin alone (MA). In addition, platelet indices and fibrinogen concentrations were determined. RESULTS: Thirteen dogs with complicated B&#xa0;rossi infection and five healthy controls were included. The median MAand fibrinogen concentrations were significantly higher (P&#xa0;<&#xa0;0.01 for both) and median platelet count was significantly lower (P&#xa0;<&#xa0;0.01) in the babesiosis group vs the control group. No significant differences were found for MAand MA. maximum amplitude due to fibrin alone was positively correlated with fibrinogen concentration (r&#xa0;=&#xa0;0.735), mean platelet volume (r&#xa0;=&#xa0;0.517), and mean platelet mass (r&#xa0;=&#xa0;0.498), and negatively correlated with hematocrit (r&#xa0;=&#xa0;-0.685), platelet count (r&#xa0;=&#xa0;-0.476), and plateletcrit (r&#xa0;=&#xa0;-0.479) (P&#xa0;<&#xa0;0.05 for all). CONCLUSIONS: This study suggests that the presence of hyperfibrinogenemia offsets the severe thrombocytopenia associated with B rossi to result in normal thromboelastograms and lack of overt clinical bleeding.