Article

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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    • "The inflammatory response to infection can activate the coagulation system via complex interactions and can result in a consumptive coagulopathy (Esmon et al., 1999; Laforcade et al., 2003; Weiss and Rashid, 1998). Coagulation derangement, specifically hypercoagulability, is considered likely in a number of systemic diseases affecting small animals (Donahue and Otto, 2005; Kristensen et al., 2008; Otto et al., 2000; Wiinberg et al., 2008, 2009). If uncontrolled, the hypercoagulable state may lead to DIC, which has been identified as a major risk factor for poor outcome in both human and canine medicine (Laforcade et al., 2003; Weiss and Rashid, 1998). "
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    • "Because of its ability to evaluate cell-to-protein interaction during clot formation, TEG has been proposed as a useful tool to detect hypercoagulability in dogs (Otto et al., 2000; Donahue and Otto, 2005). TEG is a sensitive tool closely correlated with the clinical phenotype in selected hemostatic disorders (Wiinberg et al., 2009). We propose recalcified ⇑ Corresponding author at: Department of Small Animal Clinical Sciences and Veterinary Teaching Hospital, Michigan State University, East Lansing, MI 48824, USA. "
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    • "Thromboelastometry (TEM) investigates the coagulation process by evaluating the viscoelastic properties of the blood clot from its formation to fibrinolysis [5]. It is widely employed in human medicine, and recently it has been validated in many species including equine [6] [7] [8] [9]. TEM could thus be a useful and noninvasive tool to obtain early information about the haemostatic profile in horses affected by EIPH. "
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