Cardiac troponin I as a marker for severity and prognosis of cardiac disease in dogs

The use of cardiac troponin I (cTnI) to assess the severity of disease and prognosis in 120 dogs presented for cardiac evaluation was analysed. cTnI concentrations were measured using a commercially available assay. Dogs were placed into three groups: group 1, cTnI ⩽ 0.15 ng/mL; group 2, cTnI 0.151–1.0 ng/mL; group 3, cTnI>1.01 ng/mL. Dogs in group 1 were significantly younger (P < 0.0001) and had no or stable cardiac diseases and longest survival times, whereas those in groups 2 and 3 had severe cardiac diseases and significantly reduced survival times (P < 0.0001).Thirty dogs with initially increased cTnI concentrations had a repeat assay less than 2 months later with significant reductions in cTnI concentrations (P = 0.005). Initial cTnI concentrations could not differentiate dogs that survived in group 3 from those that did not. However, dogs that survived showed significant cTnI reductions (P = 0.015) in the repeated assay in contrast to the dogs that died (P = 0.22). It was concluded that cTnI is useful in assessing the prognosis and severity of cardiac diseases in dogs, and progression and response to treatment can be assessed by repeat sampling. cTnI concentrations >1.0 ng/mL and persistent increases in cTnI concentrations are indicators of a poor prognosis in dogs with cardiac disease.