The 2-sided reference change value for NT-proBNP was significantly lower in dogs with mitral regurgitation compared to healthy controls (52.5% vs 99.4%, P<0.01).
Observational (n=21)
What is the biologic variability and reference change value of NT-proBNP and cardiac troponin-I in healthy dogs and dogs with mitral regurgitation?
High individuality of NT-proBNP and C-TnI in dogs suggests these biomarkers are best interpreted by serial determination in individual patients rather than by comparison to population-based reference intervals.
Absolute Event Rate: 52.5% vs 99.4%
p-value: p=<0.01
BACKGROUND: The N-terminal fragment of the prohormone B-type natriuretic peptide (NT-proBNP) and cardiac troponin-I are candidate biomarkers for cardiac disease in dogs. The degree of biologic variation in these biomarkers has not previously been reported in healthy dogs or dogs with mitral regurgitation. OBJECTIVES: The purpose of the study was to derive estimates of intrinsic biologic variability and reference change values for NT-proBNP and cardiac troponin-I in healthy dogs and dogs with mitral regurgitation grade IB and II according to the International Small Animal Cardiac Health Council (ISACHC) grading system. METHODS: Plasma and sera were collected weekly for up to 7 weeks from 12 control dogs and 9 dogs with mitral regurgitation. NT-proBNP and troponin-I (C-TnI) concentrations were determined. Indices of biologic variation such as reciprocal index of individuality (r-IoI) and reference change values (RCV) were calculated in both the groups. RESULTS: Individuality was high in control dogs and dogs with grade IB and II mitral valve regurgitation for both C-TnI (r-IoI 1.6 and 2) and NT-proBNP (1.5 and 2.7), while the 2-sided RCV for NT-proBNP was significantly lower in dogs with mitral regurgitation (52.5% vs 99.4%, P<0.01.). CONCLUSIONS: High individuality of these cardiac biomarkers suggests that, following diagnosis, these assays are best interpreted by serial determination in individual canine patients rather than by comparison to a population-based reference interval. The smaller RCV values for dogs with mitral regurgitation suggest that smaller relative changes in NT-proBNP are clinically meaningful in these patients.
Ruaux et al. (2015) conducted an observational in Mitral valve degeneration (n=21). Serial determination of NT-proBNP and cardiac troponin-I vs. Healthy control dogs was evaluated on Indices of biologic variation such as reciprocal index of individuality (r-IoI) and reference change values (RCV) (p=<0.01). The 2-sided reference change value for NT-proBNP was significantly lower in dogs with mitral regurgitation compared to healthy controls (52.5% vs 99.4%, P<0.01).