The clinical utilities of cardiac biomarkers are known to diagnose congestive heart failure in dogs. Although cough is common clinical symptom in mitral valve disease (MVD) prior to cardiogenic pulmonary edema, it can also be caused by respiratory diseases. We hypothesized that measuring plasma atrial natriuretic peptide (ANP) and N-terminal proB-type natriuretic peptide (NT-proBNP) levels in dogs have a clinical utility for distinguishing respiratory signs between cardiac and non-cardiac causes. This retrospective clinical study consisted of 65 dogs with respiratory signs: respiratory diseases (RD; n=32) and MVD without cardiogenic pulmonary edema (MVD; n=33). All dogs underwent physical examination, echocardiography, thoracic radiography, and blood sampling before treatment. Plasma concentration of ANP and NT-proBNP were measured using commercial laboratories. Plasma ANP and NT-proBNP concentrations were significantly higher in dogs with MVD as compared with the RD (both P<0.01). Use of plasma ANP concentration >49.1 pg/mL to identify dogs with MVD had a sensitivity of 84.9% and a specificity of 92.5%. When using plasma NT-proBNP concentration >797 pmol/L to identify dogs with MVD, the sensitivity was 81.8% and specificity 75.8%. The area under the receiver-operating characteristic curve were 0.94 and 0.86, respectively. Our results indicated that plasma ANP and NT-proBNP measurements have a potential as an additional screening method to distinguish respiratory signs of cardiac cause from those of non-cardiac cause.
