Evaluation of a high-sensitivity cardiac troponin I assay compared to a first-generation cardiac troponin I assay in Doberman Pinschers with and without dilated cardiomyopathy.

BACKGROUND: Echocardiography and 24-hour ECG are the gold standard tests to diagnose dilated cardiomyopathy (DCM) in Doberman Pinschers (DP), but myocardial damage might be detected earlier using a high-sensitivity cardiac troponin I (hs-cTnI) assay.

OBJECTIVE: To evaluate and compare an hs-cTnI assay (Advia Centaur TnI-Ultra assay) with a conventional cTnI assay in DP with different stages of DCM and in healthy DP.

ANIMALS: Three hundred forty-five examinations from 162 DP with and 179 DP without DCM.

METHODS: Prospective longitudinal study. Dogs were allocated into 6 groups based on echocardiographic and 24-hour ECG criteria: (1) healthy group (179 dogs), (2) last-normal group (29 dogs), which included dogs that were considered to be healthy at the time of their examination but were assigned to the last-normal group retrospectively when DCM was diagnosed at their next examination within 1.5 years, (3) only arrhythmias (45 dogs, 119 examinations), (4) only echocardiographic changes (24 dogs, 61 examinations), (5) echocardiographic changes with ventricular premature complexes (41 dogs, 100 examinations), and (6) decompensated (23 dogs, 36 examinations). Hs-cTnI and conventional cTnI concentration measurements were performed and compared.

RESULTS: A cutoff value of hs-cTnI concentration >0.113 ng/mL had a sensitivity of 81.2% and a specificity of 73.2% to identify the presence of DCM. The conventional cTnI assay showed a similar test performance, but the hs-cTnI assay identified more dogs (21/29 dogs, 72%) in the last-normal group compared to the conventional cTnI test (18/29 dogs, 62%).

CONCLUSIONS AND CLINICAL IMPORTANCE: The hs-cTnI is an additional test with good potential to identify early DCM.