Serum cardiac troponin I in dogs with primary immune-mediated haemolytic anaemia

OBJECTIVES: The assessment of serum cardiac troponin I concentrations in dogs with a range of nonprimary cardiac illnesses has revealed that cardiac myocyte damage is commonplace in many canine diseases. Whilst it is well established that dogs with fatal immune-mediated haemolytic anaemia frequently have cardiac pathology based on post-mortem examinations, there is limited information on the incidence of cardiac myocyte damage in this population of dogs. METHODS: Serum cardiac troponin I concentrations were measured in 11 healthy dogs, 27 dogs with primary haemolytic anaemia and 49 hospitalised dogs without primary cardiac or haematological disorders. RESULTS: Dogs with primary haemolytic anaemia have higher serum concentrations of cardiac troponin I than hospitalised ill dogs (P<0.005) and healthy dogs (P<0.01). Using a cut-off of less than 0.1 ng/mL, 20 of 27 dogs with primary haemolytic anaemia had increased serum cardiac troponin I concentrations, which was a significantly higher proportion compared to the hospitalised ill dogs (P<0.001, 16 out of 49 dogs) and healthy dogs (P<0.05, 3 out of 11 dogs). CLINICAL SIGNIFICANCE: Dogs with primary haemolytic anaemia have a higher incidence of subclinical myocyte damage than healthy dogs or dogs with non-haematological or primary cardiac illnesses. The prognostic significance of increased serum cardiac troponin I concentrations in dogs with primary haemolytic anaemia merits further investigation.