Evaluation of serum cardiac troponin-I concentrations for diagnosis of infective endocarditis in dogs
Infectious endocarditis (IE) is a microbial infection that causes inflammation of at least one of the cardiac valves or the endocardial surface of the cardiac chambers.
An antemortem definitive diagnosis is frequently difficult and depends on the satisfaction of the modified Duke criteria. Nonetheless, there are several inevitable limitations in these criteria, such as the fact that the minor criteria are mainly systemic and nonspecific signs.
The circulating serum concentration of cardiac troponin-I (cTnI) is frequently increased in cases of myocardial necrosis and inflammation. This rise is common in humans with IE, in whom abnormal cTnI concentrations are also related to worse outcomes. Nevertheless, the use of cTnI as a diagnostic or prognostic marker in dogs with IE has not been reported.
The goal of this retrospective study was to determine if the serum concentration of cTnI could differentiate dogs with IE from two other groups: those with myxomatous mitral valve disease (MMVD) and immune-mediated disease (IMD). It was hypothesized that the serum concentration of cTnI would be significantly higher in dogs with IE and that this increase would be also related to poorer survival time.
Twenty-nine dogs with IE, 27 with MMVD and 16 with IMD were included in the study. Twenty-six of the IE dogs fulfilled the modified Duke criteria for a definitive diagnosis of IE. The remaining 3 where diagnosed by the attending diplomate.
Significant differences related to serum concentrations of cTnI between the three groups were detected, with the IE group having higher values. In this group of animals, cTnI proved to be a useful diagnostic tool to distinguish between dogs with IE and other cardiac valve lesions. A cut-off value of 0.625ng/ml proved to have 100% specificity.
Any other additional testes can help diagnose IE when it is based solely on the modified Duke criteria. Therefore, the authors propose that the use of a serum concentration of > 0.65ng/ml be used as a minor criterion in dogs. Even so, it mustn’t be forgotten that, due to low sensitivity, it is not possible to rule out IE with lower values.
Kilkenny, E, Watson, C, Dukes-McEwan, J, et al. Evaluation of serum cardiac troponin-I concentrations for diagnosis of infective endocarditis in dogs. J Vet Intern Med. 2021; 35( 5): 2094- 2101. https://doi.org/10.1111/jvim.16234
