Distinguishing cardiac and noncardiac dyspnea in 48 dogs using plasma atrial natriuretic factor, B-type natriuretic factor, endothelin, and cardiac troponin-I

Background: It is challenging to differentiate congestive heart failure (CHF) from noncardiac cause of dyspnea. Hypothesis: Circulating concentrations of atrial natriuretic peptide (NT-proANP), B-type natriuretic peptide (BNP), endothelin-1 (ET-1), and cardiac troponin-I (cTnI) can be used to help distinguish between cardiac and noncardiac causes of dyspnea in dogs. Animals: Forty-eight client-owned dogs admitted to a veterinary teaching hospital for respiratory distress. Methods: Blood samples from patients were prospectively obtained. The etiology of dyspnea was determined by using physical examination, thoracic radiographs, and echocardiography. Results: CHF was diagnosed in 22 dogs, and dyspnea of noncardiac origin (noHD group) was diagnosed in 26 dogs. Analyses revealed significant difference between groups for NT-proANP (geometric mean, 95% confidence [CI]; no HD: 0.26 nmol/mL, 95% CI 0.17-1.09; CHF: 1.38 nmol/mL, 95% CI 1.09-1.74 nmol/mL; P < .0001), BNP (noHD: 12.18 pg/mL, 95% CI 10.91-16.17 pg/mL; CHF: 34.97 pg/mL, 95% CI 23.51-52.02 pg/mL; P < .0001), and ET-1 (noHD: 0.32 fmol/mL, 95% CI 0.23-0.46 fmol/mL; CHF: 1.26 fmol/mL, 95% CI 0.83-1.91 fmol/mL; P < .0001). Plasma cTnI concentrations were not significantly different between groups (noHD: 0.29 ng/mL, 95% CI 0.12-0.72 ng/mL; CHF: 0.42 ng/mL, 95% CI 0.18-0.97, P = .53). Receiver operating curves indicated areas under the curve for NT-proANP, BNP, and ET-1 of 0.946, 0.886, and 0.849, respectively. Conclusions and Clinical Importance: Plasma NT-proANP, BNP, and ET-1, but not cTnI, appear useful for distinguishing between dogs with cardiac and noncardiac causes of dyspnea, with plasma NT-proANP having the highest sensitivity (95.5%) and specificity (84.6%).