Comparison of a viscoelastic point‐of‐care coagulation monitor with thromboelastography in sick dogs with hemostatic abnormalities

Abstract

Background: Viscoelastic coagulation monitor (VCM-Vet) is a point-of-care device that has been used to characterize hemostatic abnormalities in sick pets but has not been validated in veterinary patients. Objectives:We aimed to compare VCM-Vet and thromboelastography (TEG) in sick dogs with suspected disorders of hemostasis.Methods: Duplicate VCM-Vet tests using untreated native blood performed concurrently on two VCM-Vet machines, and simultaneous TEG tests were performed (one citrated native (CN), and one activated with tissue factor (TF) at a 1:3600 dilution).Each VCM-Vet result was compared with both TF-activated and CN TEG.Results: Fifty-three dogs were enrolled. Eleven cases displayed apparent hyperfibrinolysis. Spearman correlation coefficients for individual VCM-Vet devices and CN and TF TEG were obtained between R and CT values and ranged from 0.21 to 0.27, CFT and K (r = 0.60-0.67), angles (r = 0.51-0.62), and MCF and MA (r = 0.85-0.87).Comparison of the two VCM-Vet devices displayed positive correlations for all clot formation parameters with Lin's concordance correlation coefficients of 0.75-0.95.Variable lysis parameter agreement existed between the VCM-Vet devices and VCM-Vet and TEG. When samples were classified as hypercoagulable or coagulopathic, VCM-Vet had a low positive predictive value (17-33%) for the detection of hypercoagulable states and a moderate negative predictive value (64-74%) for the detection of coagulopathy as defined by TEG.Conclusions: VCM-Vet and TEG had variable correlations in clot formation values and a strong correlation for final clot strength. More information is needed to make conclusions about the lysis parameters. Artifact in the fibrinolysis portion of the test can confound the interpretation of VCM-Vet results.

Demonstration of hyperfibrinolysis on the VCM Vet in a dog with Angiostrongylus vasorum

“…11 It should be noted, however, that a fibrinolysis artefact of unknown origin has been noted with the VCM Vet, suggesting that concern over hyperfibrinolysis should be re-confirmed with a repeated sample. 7 The lysis index, measured at 30 (LI30) and 45 (LI45) minutes following maximum clot firmness, is a calculated value derived from the relationship between amplitude and maximum clot firmness, demonstrating the percentage of remaining clot firmness. 8 The lysis index, therefore, is used to evaluate plasmin-mediated fibrinolysis.…”

“…To date, the VCM Vet has not specifically been reported in the assessment of hyperfibrinolysis due to A. vasorum , although changes in the lysis index have been noted in healthy dogs during the perianaesthetic period, 10 and a recent retrospective study extensively evaluated fibrinolysis demonstrated by the VCM Vet in a variety of diseased patients 11 . It should be noted, however, that a fibrinolysis artefact of unknown origin has been noted with the VCM Vet, suggesting that concern over hyperfibrinolysis should be re‐confirmed with a repeated sample 7 …”

“…Thromboelastography and ROTEM devices are prone to variation due to pre‐analytical error such as movement artefact and the requirement for a variety of different activators 5 . The Viscoelastic Coagulation Monitor (VCM Vet) correlates well with ROTEM 6 and TEG, 7 providing an alternative bedside global assessment of haemostasis. The VCM Vet aims to eliminate the pre‐analytical error noted in TEG and ROTEM by using whole blood without additional reagents, 8 and has been shown to perform well in the clinical setting 9 …”