Tissue factor activated thromboelastography correlates to clinical signs of bleeding in dogs

The Small Animal Hospital, Department of Small Animal Clinical Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg DK-1870, Denmark
The Veterinary Journal (Impact Factor: 2.17). 01/2009; DOI: 10.1016/j.tvjl.2007.08.022

ABSTRACT The ability of a laboratory assay to correlate to clinical phenotype is crucial for the accurate diagnosis and monitoring of haemostasis and is therefore challenging with currently used routine haemostasis assays. Thromboelastography (TEG) is increasingly used to evaluate haemostasis in humans and may well be of value in the workup of dogs suspected of having a haemostatic disorder. This study was undertaken to evaluate prospectively how tissue factor (TF) activated TEG correlated to clinical signs of bleeding in dogs, compared to a routine coagulation profile. A prospective case-control study was performed over a 2 year period from 2004–2006. Eligible dogs were those where the primary clinician requested a coagulation profile to evaluate haemostasis. The dogs were simultaneously evaluated with a TF-activated TEG assay. Twenty-seven dogs, characterised as hypo-coagulable based on the TEG parameter G (<3.2K dyn/cm2), were included in the study as cases. Size matched control groups of TEG normo- (G = 3.2K–7.2K dyn/cm2) and hyper-coagulable (G > 7.2K dyn/cm2) dogs were selected retrospectively from the eligible dogs. For all dogs, clinical signs of bleeding were noted at time of analysis.There were statistically significant differences between all TEG values of hypo- and normo- and hyper-coagulable dogs. Thromboelastography correctly identified dogs with clinical signs of bleeding with a positive predictive value (PPV) of 89% and a negative predictive value (NPV) of 98% based on G alone. In comparison, the coagulation profile had a PPV between 50–81% and a NPV between 92–93% for detection of bleeding, depending on the observer. In conclusion, a TF-activated TEG G value < 3.2K dyn/cm2 correctly identified dogs with clinical signs of bleeding with very high PPV and NPV, irrespective of observer. The findings strongly suggest that TF- activated TEG may be of value in the workup of dogs suspected of having a haemostatic disorder.

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    ABSTRACT: Objective To review the literature supporting or discouraging the use of fresh frozen plasma (FFP) transfusion in critically ill patients.Data SourcesHuman and animal publications were searched using PubMed without time limits and the following keywords were used: “fresh frozen plasma,” “coagulopathy,” “hypocoagulable state,” “hypercoagulable states,” and “critical illness.”Human Data SynthesisThe commonly used tests of coagulation (eg, prothrombin time, activated partial thromboplastin time, international normalized ratio) are poorly predictive of clinical bleeding. FFP use in critically ill patients is unlikely to result in improved outcomes and may be associated with increased risks.Veterinary Data SynthesisThere is insufficient evidence to make definitive conclusions regarding the use of FFP in critically ill animals, but clinical studies are underway that may provide further data that clarify the optimal use of FFP in animals.Conclusions The use of FFP in critically ill patients remains controversial. In the absence of clinical bleeding or a risk for clinical bleeding associated with a planned procedure, treatment use of FFP is not recommended in human patients. There are insufficient data in critically ill animals to enable formulation of recommendations. Further research is warranted in dogs and cats to establish evidence-based guidelines.
    01/2015; 25(1). DOI:10.1111/vec.12280
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    ABSTRACT: Objectives To describe a population of critically ill dogs receiving dalteparin monitored with an anti-Xa assay, to assess the potential utility of serial monitoring, and to investigate the association between pre-treatment thromboelastography (TEG) and the ability to achieve targeted anti-Xa activity.DesignDescriptive retrospective study.SettingVeterinary teaching hospital.AnimalsThirty-eight client-owned dogs receiving dalteparin and monitored with an anti-Xa assay.InterventionsNone.Measurements and Main ResultsMedical records were retrospectively reviewed for signalment, underlying disease, clinicopathological data, occurrence of thromboembolic events, complications, and outcome. Thirty-eight dogs receiving dalteparin were monitored with an anti-Xa assay. Diseases included hematological disease, protein-losing disease, neoplastic disease, and septic processes. Pretreatment hypercoagulability was present in 34/35 dogs by assessment of TEG. Five cases of thromboembolism were confirmed prior to starting treatment and 4 cases occurred during hospitalization. Bleeding complications were rare (3/38) and 29/38 dogs survived to discharge. Interpretation of the anti-Xa assay allowed for dose adjustment although reliable achievement of target anti-Xa activity was not demonstrated. Dogs with higher G values on pretreatment TEG were significantly less likely to achieve the target anti-Xa activity (ie, be above or below the target range).Conclusions Dalteparin was well tolerated in a heterogeneous population of dogs. However, dose adjustment in response to anti-Xa activity interpretation inconsistently resulted in subsequent attainment of the target anti-Xa range. Development of guidelines may be warranted to more consistently achieve the target range. Dogs that appear more hypercoagulable on pre-treatment TEG may require closer monitoring and greater dose adjustment to achieve the target anti-Xa range.
    07/2014; 24(4). DOI:10.1111/vec.12206