Cardiac Troponin I Is Associated with Severity of Myxomatous Mitral Valve Disease, Age, and C-Reactive Protein in Dogs

Background Concentrations of cardiac troponin I (cTnI) and C-reactive protein (CRP) might be associated with cardiac remodeling in dogs with myxomatous mitral valve disease (MMVD). Age- and sex-dependent variations in cTnI concentration have been described. Objective To investigate whether plasma concentrations of cTnI and CRP are associated with severity of MMVD, and investigate potential associations of dog characteristics on cTnI and CRP concentrations. Animals Eighty-one client-owned dogs with MMVD of varying severity. Methods Dogs were prospectively recruited for the study. Dogs were classified according to severity of MMVD. Plasma cTnI was analyzed by a high sensitivity cTnI assay with a lower limit of detection of 0.001 ng/mL, and plasma CRP was analyzed by a canine-specific CRP ELISA. Results Higher cTnI concentrations were detected in dogs with moderate (0.014 [interquartile range 0.008-0.029] ng/mL, P = .0011) and severe (0.043 [0.031-0.087] ng/mL, P < .0001) MMVD, compared with healthy dogs (0.001 [0.001-0.004] ng/mL). Dogs with severe MMVD also had higher cTnI concentrations than dogs with mild (0.003 [0.001-0.024] ng/mL, P < .0001) and moderate (P = .0019) MMVD. There were significant associations of age, CRP, heart rate, and left ventricular end-diastolic diameter, on cTnI concentration C-reactive protein did not differ among severity groups, but was significantly associated with cTnI, breed, and systolic blood pressure on CRP concentration. Conclusions and Clinical Importance Analysis of cTnI concentration has potential to increase knowledge of overall cardiac remodeling in dogs with MMVD. However, effect of age on cTnI needs consideration when assessing cTnI.