Evaluation of plasma N-terminal pro-B-type natriuretic peptide concentrations in dogs with and without cardiac disease

OBJECTIVE: To evaluate plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations in a large, diverse population of dogs with and without cardiac disease and to define the upper reference limit for the biomarker in this species. DESIGN: Cross-sectional single center study. ANIMALS: 1,134 dogs. PROCEDURES: Dogs underwent blood sample collection, physical examination, ECG, and echocardiographic and thoracic radiographic evaluations. Cardiac status was graded by use of a 9-grade cardiac disease classification system and a simplified 4-stage cardiac scoring system. Vertebral heart score (VHS) was assessed in 280 dogs. Associations of plasma NT-proBNP concentrations with multiple variables were evaluated via univariate and multivariate linear regression analysis. Sensitivity and specificity of NT-proBNP concentrations and of VHS to discriminate between dogs with and without clinical signs of cardiac disease were evaluated via receiver-operating characteristic curve analysis. RESULTS: 974 dogs had cardiac disease, 37 had noncardiac-related disease, and 123 were healthy. Plasma NT-proBNP concentrations correlated with cardiac grade and stage; VHS was also associated with cardiac grade. At a cutoff of 874 pmol/L, sensitivity and specificity of NT-proBNP concentration to detect clinical signs of cardiac disease were 70% and 83%, respectively; for VHS, sensitivity and specificity were 56% and 85%, respectively, at a cutoff of 11.5. Mean NT-proBNP concentration was significantly increased in dogs with cardiac-related dyspnea or coughing, compared with dogs in which these signs were noncardiac related. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that 900 pmol/L is the upper reference limit of plasma NT-proBNP concentration in dogs. This biomarker may be a useful tool for staging of cardiac disease and identifying cardiac-related coughing or dyspnea in this species.