Clinical efficacy of a benazepril and spironolactone combination in dogs with congestive heart failure due to myxomatous mitral valve disease: The BEnazepril Spironolactone STudy (BESST)

Cardiovascular disease is currently treated with drugs that inhibit the renin-angiotensin-aldosterone system (RAAS). The use of mineralocorticoid receptor antagonists has gained a significant importance in the treatment of congestive heart failure (CHF) in humans, partly due to the beneficial effects of adding spironolactone (S) to the standard therapy for CHF.

The authors of this multicentric prospective study hypothesized that a combination of spironolactone and benazepril (S +BNZ) would be superior to the use solely of benazepril (BNZ), when administered together with furosemide and other treatment options for CHF in dogs with myxomatous mitral valve disease (MMVD).

Four hundred and fourteen dogs, of different ages and breeds, that presented signs of CHF associated to MMVD were included in the study. Dogs were randomly sorted into 2 groups: the first group received a combination of S + BNZ (2mg/kg and 0.25mg/kg) once daily. The second group received only BNZ in the same dosage and frequency. The dosage of furosemide administered to these dogs was ≤ 6mg/kg at day zero of the study.

Authors determined that the studied combination of S + BNZ administered together with furosemide was safe. S + BNZ revealed superior results when compared to the sole use of BNZ (alongside furosemide and other common therapies), through analysis of several variables during the study. The percentage of dogs that were removed from the study (due to death/euthanasia or the need to increase the dose of furosemide) was significantly lower (difference of 27%) in the combination group in comparison to the other group. A quick and persistent benefit from the use of S + BNZ was also observed in comparison to the use of just BNZ.

With this study, authors were able to assume that the use of this combination can reduce or even delay the recurrence of signs of CHF while also reducing the percentage of deaths over a 12-month period.

Coffman, M., Guillot, E., Blondel, T., et al. (2021) Clinical efficacy of a benazepril and spironolactone combination in dogs with congestive heart failure due to myxomatous mitral valve disease: The BEnazepril Spironolactone STudy (BESST). J Vet Intern Med.; 35( 4), pp. 1673– 1687. https://doi.org/10.1111/jvim.16155