van Rooyen Liesl J, Hooijberg Emma H, Schoeman Johan P, Goddard Amelia
Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.
IDEXX Laboratories (Pty) Ltd., Johannesburg, South Africa.
Vet Clin Pathol. 2019 Mar;48(1):11-18. doi: 10.1111/vcp.12689.
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.
This study investigated potential differences in TEG-PM variables in dogs with complicated B rossi infection compared with healthy controls, and whether these variables correlated with platelet activation indices.
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.
Thirteen dogs with complicated B rossi infection and five healthy controls were included. The median MA and fibrinogen concentrations were significantly higher (P < 0.01 for both) and median platelet count was significantly lower (P < 0.01) in the babesiosis group vs the control group. No significant differences were found for MA and MA . maximum amplitude due to fibrin alone was positively correlated with fibrinogen concentration (r = 0.735), mean platelet volume (r = 0.517), and mean platelet mass (r = 0.498), and negatively correlated with hematocrit (r = -0.685), platelet count (r = -0.476), and plateletcrit (r = -0.479) (P < 0.05 for all).
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.
感染罗氏巴贝斯虫的犬尽管明显血小板减少，但血栓弹力图显示凝血正常，这据说是由于大规模血小板活化所致。血栓弹力图血小板图谱（TEG-PM）评估凝血酶、纤维蛋白原和血小板对凝块形成的个体贡献，可能阐明血小板减少相关止血改变的一些发病机制。
本研究调查了与健康对照相比，患有复杂罗氏巴贝斯虫感染的犬的TEG-PM变量的潜在差异，以及这些变量是否与血小板活化指标相关。
使用高岭土激活的TEG测定凝血酶生成后的最大振幅（MA）。TEG-PM变量包括添加血小板激动剂花生四烯酸后的MA（MA ）和二磷酸腺苷后的MA（MA ），以及仅由纤维蛋白引起的MA（MA ）。此外，还测定了血小板指标和纤维蛋白原浓度。
纳入了13只患有复杂罗氏巴贝斯虫感染的犬和5只健康对照。与对照组相比，巴贝斯虫病组的MA中位数和纤维蛋白原浓度显著更高（两者均P < 0.01），血小板计数中位数显著更低（P < 0.01）。MA 和MA 未发现显著差异。仅由纤维蛋白引起的最大振幅与纤维蛋白原浓度（r = 0.735）、平均血小板体积（r = 0.517）和平均血小板质量（r = 0.498）呈正相关，与血细胞比容（r = -0.685）、血小板计数（r = -0.476）和血小板压积（r = -0.479）呈负相关（所有P < 0.05）。
本研究表明，高纤维蛋白原血症的存在抵消了与罗氏巴贝斯虫相关的严重血小板减少，从而导致正常的血栓弹力图和无明显临床出血。
