Sex and Neuter Status Affect the Clinical Application of N-Terminal Pro-Brain Natriuretic Peptide as A Survival Biomarker in Dogs with Congestive Heart Failure

We aimed to evaluate the utility and sex dependence of serum N-terminal pro-brain natriuretic peptide (NT-proBNP concentration) as a predictor of survival and treatment response in dogs with heart failure. We hypothesized that the serial trend of NT-proBNP levels would be predictive of outcomes and be independent of sex and neuter status in dogs with congestive heart failure secondary to myxomatous mitral valve disease. This prospective study enrolled 18 privately owned dogs with congestive heart failure and no previous diuretic treatment. Serial NT-proBNP measurements were performed at admission (treatment initiation) and during follow-up (on days 7 and 21). The NT-proBNP concentration at admission or at any of the two follow-up examinations did not differ significantly between dogs that survived and those that died of cardiac causes. Intact male dogs with an ascending trend of NT-proBNP levels between admission and the second follow-up died within 200 days, whereas those with a descending trend survived up to 500 days. However, no such relationship was observed for neutered males or spayed females. Our findings suggest that an ascending trend of NT-proBNP levels is indicative of a higher risk of cardiac-related death in intact male dogs with congestive heart failure receiving treatment, warranting careful monitoring. Furthermore, NT-proBNP measurements performed later than two weeks after treatment initiation provide better prognostic capabilities. 2019 PVJ.