Evaluation of serum cardiac troponin‐I concentrations for diagnosis of infective endocarditis in dogs

Abstract

Background Infective endocarditis (IE) in dogs is associated with severe disease and a high case fatality rate but often presents with nonspecific clinical signs. Hypothesis/Objectives Serum concentration of cardiac troponin‐I (cTnI) is elevated in dogs with IE and can differentiate dogs with IE from dogs with other diseases with similar clinical features. Concentration of serum cTnI is negatively correlated with survival time in dogs with IE. Animals Seventy‐two client‐owned dogs; 29 with IE, 27 with stage‐B myxomatous mitral valve disease (MMVD), and 16 with immune‐mediated disease (IMD). Methods Retrospective clinical cohort study. Concentration of serum cTnI was measured in all dogs at time of diagnosis. Clinical findings and echocardiographic interpretation were also recorded. Statistical analyses included Kruskal‐Wallis test, pairwise Mann‐Whitney U tests, receiver operator characteristic, and Cox proportional hazards. Results Serum concentration of cTnI was significantly higher in the IE group (0.69 ng/mL [0.03‐80.8]) than in the MMVD (0.05 ng/mL [0.02‐0.11], P < .001) and IMD groups (0.05 ng/mL [0.03‐0.57], P < .001). Increased cTnI was a moderately accurate predictor of IE (area under the curve 0.857 (95% confidence interval [CI] 0.745‐0.968, P < .001). A cTnI cutoff of 0.625 ng/mL had 100% specificity (95% CI 90%‐100%) and 52% sensitivity (95% CI 33%‐70%) in this study sample. There was no association between cTnI concentration and survival time in dogs with IE (hazard ratio 1.013, 95% CI 0.993‐1.034, P = .2). Conclusions and Clinical Importance Cardiac troponin‐I concentrations are higher in dogs with IE compared to dogs with preclinical MMVD or IMD. In dogs with a compatible clinical presentation, serum cTnI concentrations >0.625 ng/mL are supportive of IE.

Infective endocarditis in dogs in theUK: 77 cases (2009‐2019)

“…and Pasteurella spp., which have all been reported in previous USA studies (MacDonald et al 2004, Sykes et al 2006a, Reagan et al 2022. The mitral valve was most commonly infected in this study as shown in recent studies (Kilkenny et al 2021;Reagan et al 2022). This differs from previous studies however where both the aortic and mitral valve were frequently affected (Sykes et al 2006a).…”

“…The mean age at which dogs were infected with IE in this study was similar in males and in females. A higher proportion of middle-aged to older dogs were reported with IE in this study as noted in previous studies (Sisson & Thomas 1984, Sykes et al 2006b, Kilkenny et al 2021, Reagan et al 2022. This may be due to age-related senescence of the immune system, which has been shown to increase the incidence of infection in older pets (Day 2010).…”

“…This multi-centre study represents the first review of canine IE in a referral population of dogs in the UK and the second largest case series of IE to date. Large and medium breed dogs appear to be more predisposed to developing IE than small breed dogs, as has been described in previous veterinary studies (Sisson & Thomas 1984, Peddle & Sleeper 2007, Kilkenny et al 2021, Reagan et al 2022. However, reasons for this remain unclear.…”

“…Although only 30 of our patients had serum cTnI levels measured, it was not shown to be helpful as a prognostic indicator. A recent study has shown that serum cTnI concentrations above >0.625 ng/ml are supportive of a diagnosis of IE (Kilkenny et al 2021). This cut-off could be useful as an additional minor criterion in the Duke's modified criteria; however, it has a high specificity and a low sensitivity, therefore, it must be used within the context of the overall clinical picture.…”

“…However, a modified version of the human Duke criteria used for diagnosis of IE in dogs has been described (Sykes et al 2006a). Although not part of the Duke criteria, cardiac troponin-I (cTnI) is another supportive test for IE (Kilkenny et al 2021). The most common bacteria identified in previous studies of dogs with IE were Streptococcus spp.…”