Brain natriuretic peptide concentration in dogs with heart disease and congestive heart failure

Plasma brain natriuretic peptide concentration (BNP]) is high in humans with cardiac disease and is further increased with congestive heart failure (CHF). The hypotheses of this study were that dogs with moderate to severe mitral regurgitation due to myxomatous mitral valve disease (MVD) would have increased plasma BNP] compared to normal dogs, that plasma BNP] would be higher in dogs with CHP, and that plasma BNP] would predict premature death from cardiovascular disease. The study population consisted of 34 dogs: 9 normal dogs and 25 dogs with MVD. Patients were divided into 4 groups: group 1-10 dogs with moderate to severe MVD and no radiographic evidence of CHF; group II--6 dogs with severe MVD and mild CHF; group III--7 dogs with severe MVD and moderate CHF; and group IV--2 dogs with severe MVD and severe CHF. Diagnostic tests included thoracic radiographs, an echocardiogram, a serum chemistry profile, and the measurement of plasma BNP] by a canine-specific radioimmunoassay. There was a significant positive correlation between the plasma BNP] and heart disease/failure groups (P = .0036). Plasma BNP] increased with progressively increasing severity of MVD and CHE Group I dogs had higher plasma BNP] than did control dogs (P < .0001), and plasma BNP] was higher in dogs with CHF (groups II-IV versus group I; P = .012). Plasma BNP] was also weakly positively correlated with left atrial size (r = 0.43, P = .04). For every 10-pg/mL increase in plasma BNP], the mortality rate over 4 months' time increased approximately 44%.