Cardiorenal and endocrine effects of synthetic canine BNP1-32 in dogs with compensated congestive heart failure caused by myxomatous mitral valve disease

Background: The effects of synthetic brain natriuretic peptide (BNP1-32) on cardiorenal and renin angiotensin aldosterone system in dogs with naturally occurring congestive heart failure (CHF) are unknown. Objectives: To evaluate the cardiorenal and endocrine effects of SC administered synthetic canine BNP1-32, with or without furosemide, in dogs with CHF caused by myxomatous mitral valve disease (MMVD). Animals: Seven client-owned male dogs with compensated American College of Veterinary Internal Medicine stage C CHF caused by MMVD on chronic treatment with furosemide, benazepril, and pimobendan. Methods: A single-dose, crossover, pilot study. Each dog received a dose of BNP1-32 (5 μg/kg), furosemide (2 mg/kg), and both BNP1-32/furosemide (5 μg/kg and 2 mg/kg, respectively) SC with a 2-week washout period among each treatment. Between- and within-treatment effects were evaluated using linear mixed modeling with restricted maximum likelihood estimation and evaluation of least square differences. Results: Rapid absorption of BNP1-32 and a corresponding rise in urinary cyclic guanosine monophosphate excretion was observed at 1-2 hours after any treatment containing BNP1-32 (P <.05). However, BNP1-32 did not influence measured cardiorenal variables. Plasma aldosterone concentrations were below quantifiable levels in majority of the samples. Conclusions and Clinical Importance: No beneficial cardiorenal effects were detected. It is possible that dogs with chronic CHF have a reduction in natriuretic peptide responsiveness.