N06 - Comparison of D-dimer and Thromboelastography for Diagnosis of Cerebrovascular Accidents in Dogs

Abstract: Background- Cerebrovascular accidents (CVAs) in dogs are documented with magnetic resonance imaging (MRI). This imaging modality is not always available. Additionally, some CVAs may be too small to be detected or appear similar to other pathology on MRI. Thromboelastography (TEG) and D-dimer are utilized in human medicine for detection of CVAs but their use in veterinary patients has not been assessed.

Hypothesis/Objectives- To assess utility of TEG and D-dimer testing in diagnosing CVAs in dogs.

Animals- 76 client-owned dogs with acute onset neurologic signs having a brain MRI and TEG or D-dimer testing performed.

Methods- Multicenter, retrospective study. The incidence of abnormal TEG or D-dimer results was compared between patients with clinical or MRI evidence of CVA and a control population (neurologic diagnosis other than CVA). Analysis methods included Fisher’s or Chi-square test for association.

Results- In our population, neither TEG or D-dimer was significantly associated with a CVA (p=0.374 and 0.425, respectively). The sensitivity of TEG for CVA diagnosis was significantly higher than D-dimer in all cases (60.6% and 25.0%, respectively; p=0.042) and for cases with MRI evidence alone (TEG 66.7%, D-dimer 23.1%, p=0.025). The specificity of abnormal TEG or D-dimer for CVA diagnosis was not significantly different, even in cases with MRI evidence alone (p=0.606, p=0.440). When comparing hemorrhagic and ischemic CVAs, an abnormal TEG or D-dimer were not significantly associated with diagnosis (p=0.168 and 0.832, respectively).

Conclusions and clinical importance- Abnormal TEG or D-dimer alone is not a reliable indicator of CVA in dogs.