Serum fibroblast growth factor-23 concentration in dogs with myxomatous mitral valve disease

Circulating fibroblast growth factor-23 (FGF-23) is primarily a kidney-related biomarker, but also may be influenced by cardiovascular remodeling and hemodynamic load.

Verify whether serum FGF-23 concentration increases with myxomatous mitral valve disease (MMVD) severity.

Forty-two client-owned dogs with MMVD without overt kidney disease.

Retrospective cross-sectional study to evaluate serum FGF-23, N-terminal pro-B-type natriuretic peptide (NT-proBNP), atrial natriuretic peptide (ANP), blood urea nitrogen (BUN), creatinine (Cr), and symmetric dimethylarginine (SDMA) concentrations. Imaging variables included vertebral heart score (VHS), vertebral left atrial size (VLAS), left atrial-to-aortic root ratio (LA/Ao), normalized left-ventricular internal diameter in diastole (LVIDDN), and diastolic transmitral E-wave velocity (E-vel). Differences among American College of Veterinary Internal Medicine stages were analyzed using the Kruskal-Wallis test with Bonferroni-adjusted pairwise comparisons. Correlations were analyzed using Spearman's correlation. Multivariable linear regression analysis was performed to identify factors associated with serum FGF-23 concentration.

Dogs with ACVIM stages C and D had higher serum FGF-23 concentrations than those with stages B1 and B2 (P < .05). Serum FGF-23 concentrations were positively correlated with VLAS (rs = 0.500, P < .01), ANP (rs = 0.455, P < .01), LA/Ao (rs = 0.384, P < .05), E-vel (rs = 0.372, P < .05), and NT-proBNP (rs = 0.366, P < .05). ACVIM stage was significantly associated with serum FGF-23 concentration after adjustment for serum Cr concentration and loop diuretic use.

The potential influence of MMVD should be considered when interpreting increased circulating FGF-23 concentrations in dogs with MMVD.