Effect of Benazepril on Survival and Cardiac Events in Dogs with Asymptomatic Mitral Valve Disease: A Retrospective Study of 141 Cases

Abstract

Angiotensin-converting enzyme inhibitors (ACEIs) improve quality of life and extend the life span of dogs with naturally acquired ISACHC class II-III congestive heart failure (CHF). However, their effects on asymptomatic heart disease remain controversial. Benazepril (BNZ), an ACEI, could have beneficial effects at the asymptomatic stage of degenerative mitral valve disease (MVD). Dogs with ISACHC class Ia MVD and moderate-to-severe mitral regurgitation (MR) assessed by the color Doppler mapping technique at entry (Day 0) were retrospectively included. Dogs were assigned to the treated group (BNZ group) if they received BNZ (and no other cardiac medication) from Day 0 or to the untreated group (UT group) if they did not receive any cardioactive treatment until occurrence of CHF. A total of 141 dogs were included in the study, 66 in the BNZ group (dosage: 0.30 +/- 0.13 mg/kg) and 75 in the UT group. In the population (n = 93) including all breeds except Cavalier (CKC) and King Charles Spaniels (KC), median survival time to all causes of death in the BNZ group (n = 34, 3.3 years) was significantly longer than in the UT group (n = 59, 1.9 years) as was time to cardiac event (P < .05). Conversely, no effect of the BNZ treatment was observed in the CKC and KC population. BNZ had beneficial effects in asymptomatic dogs other than CKC and KC affected by MVD with moderate-to-severe MR. Breed distribution should be taken into account for interpretation of clinical trials performed in dogs with cardiac disease.