Gross anatomy of the deep perivertebral musculature in horses
- Autores: Nicole Rombach, Hilary M. Clayton, Narelle C. Stubbs
- Localización: American Journal of Veterinary Research, ISSN-e 1943-5681, ISSN 0002-9645, Vol. 75, Nº. 5, 2014, págs. 433-440
- Idioma: inglés
- Enlaces
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Resumen
Objective—To determine whether thromboelastography is more accurate than conventional methods of evaluating hemostasis for the prediction of clinical bleeding in thrombocytopenic dogs following total body irradiation (TBI) and bone marrow transplantation (BMT).
Animals—10 client-owned thrombocytopenic dogs with multicentric lymphoma.
Procedures—Results of a kaolin-activated thromboelastography assay, platelet count, and buccal mucosal bleeding time were evaluated for correlation to clinical bleeding.
Results—Maximum amplitude, derived via thromboelastography, was the only hemostatic variable with significant correlation to clinical bleeding. Buccal mucosal bleeding time had a high sensitivity but poor specificity for identifying dogs with clinical bleeding.
Conclusions and Clinical Relevance—Compared with buccal mucosal bleeding time and platelet count, thromboelastography was more reliable at identifying thrombocytopenic dogs with a low risk of bleeding and could be considered to help guide the use of transfusion products in dogs undergoing TBI and BMT.
Thrombocytopenia is a common abnormality in veterinary patients and an important cause of mucosal bleeding. The ability to correlate results of hemostatic assays to clinical phenotypes in such patients is an emerging topic of exploration.1 Conventional methods of predicting the risk of bleeding in thrombocytopenic veterinary patients consist of an absolute platelet count and tests of primary hemostasis, such as determination of BMBT.2 Thromboelastography and rotational thromboelastometry are diagnostic tools that use the viscoelastic properties of clot formation to provide an assessment of global coagulation, thereby identifying both hyper- and hypocoagulable states.3,4 In human medicine, thromboelastography and rotational thromboelastometry are used to monitor and guide transfusion therapy in patients with trauma-associated coagulopathy5 and those undergoing cardiac bypass or liver transplantation.6–9 Thromboelastography has also been used to monitor therapeutic efficacy of platelet transfusions in patients with chemotherapy-induced thrombocytopenia.10 In veterinary medicine, several studies have used thromboelastography as a means of assessing global hemostatic function in both healthy dogs11,12 and those with a multitude of diseases causing hypo- and hypercoagulable states, including parvovirus enteritis,13 protein-losing nephropathy,14 neoplasia,15 immune-mediated hemolytic anemia,16,17 and disseminated intravascular coagulation.18 However, the authors are aware of only 1 study1 evaluating the correlation of thromboelastography to clinical bleeding in dogs and are not aware of any studies evaluating the correlation of thromboelastography variables to clinical bleeding in dogs with thrombocytopenia as the primary contributor to abnormal hemostasis.
Immune-mediated thrombocytopenia is the most common disease in small animal veterinary medicine requiring blood transfusions as a result of thrombocytopenia.19 However, causation, onset, and progression of the disease are variable, making thrombocytopenia associated with IMTP a difficult variable to isolate and study. Total body irradiation is an iatrogenic cause of bone marrow suppression and thrombocytopenia. After TBI, thrombocytopenia predictably occurs in 7 to 10 days20 in accordance with the typical lifespan of canine circulating platelets.21,22 For this reason, dogs with B- or T-cell lymphoma undergoing autologous BMT following TBI provide a unique opportunity for evaluating hemostatic function.
The primary objective of the study reported here was to determine whether thromboelastography is more accurate than conventional methods of evaluating hemostasis for the prediction of clinical bleeding in thrombocytopenic dogs. Secondary objectives were to assess the correlation of clinically applicable hemostatic variables, specifically platelet count, BMBT, and thromboelastography-derived MA, with mucosal bleeding and spontaneous clinical bleeding events (melena, hematochezia, epistaxis, or hematuria) in a relatively uniform cohort of dogs with a known etiology for their thrombocytopenia. Other objectives included the evaluation of other readily available clinical and laboratory variables and their correlation with mucosal bleeding and clinical bleeding events as well as the analysis of platelet count and its association with thromboelastography variables. Our hypothesis was that MA would be more accurate than BMBT or platelet count at predicting clinical bleeding in thrombocytopenic dogs following TBI and BMT.
