Diagnosis of canine pulmonary thromboembolism by computed tomography and mathematical modelling using haemostatic and inflammatory variables

• Published in: The veterinary journal (1997) 2017-11, Vol.229, p.6-12
• Main Authors: Marschner, C.B., Kristensen, A.T., Rozanski, E.A., McEvoy, F.J., Kühnel, L., Taeymans, O., de Laforcade, A., Sato, A.F., Wiinberg, B.
• Format: Article
• Language: English
• Subjects: Canine; Computed tomography pulmonary angiography; D-dimer; Prediction model; Pulmonary thromboembolism
• ISSN: 1090-0233; 1532-2971
• DOI: 10.1016/j.tvjl.2017.10.010

•Two mathematical models for diagnosis of pulmonary thromboembolism (PTE) in dogs were generated.•D-dimer measurements are only useful as screening assay prior to a gold standard test.•Thromboelastography (TEG) G values were not significantly different between dogs with and without PTE.•Computed tomography pulmonary angiography (CTPA) appears to be safe and its use is supported as gold standard for diagnosis of PTE in dogs. There is no evidence-based diagnostic approach for diagnosis of pulmonary thromboembolism (PTE) in dogs. Many dogs with diseases that predispose to thrombosis are hypercoagulable when assessed with thromboelastography (TEG), but no direct link has been established. The aims of this study were: (1) to investigate if diseased dogs with PTE, diagnosed by computed tomography pulmonary angiography (CTPA), had evidence of hypercoagulability by TEG; (2) to characterise haemostatic and inflammatory changes in dogs with PTE; (3) to construct models for prediction of PTE based on combinations of haemostatic and inflammatory variables; and (4) to evaluate the performance of D-dimer measurement for prediction of PTE. Twenty-five dogs were included in this prospective observational study (PTE: n=6; non-PTE: n=19). Clot strength G values did not differ between the PTE and non-PTE groups in tissue factor (TF) or kaolin-activated TEG analyses. Haemostatic and inflammatory variables did not differ between the two groups. Linear discriminant analysis generated a model for prediction of PTE with a sensitivity and specificity of 100% when TF results were used as TEG data, and a model with sensitivity of 83% and specificity of 100% when kaolin results were used as TEG data. Receiver operating characteristic analysis of D-dimer levels showed that a value of >0.3mg/L yielded a sensitivity of 100% and a specificity of 71.4%. In conclusion, the study supports CTPA as method for diagnosing canine PTE, but shows that TEG alone cannot identify dogs with PTE. Models for prediction of PTE were generated, but require further validation.