Controlled clinical evaluation of enalapril in dogs with heart failure: results of the Cooperative Veterinary Enalapril Study Group. The COVE Study Group.

The clinical efficacy and safety of enalapril were evaluated in dogs with moderate or severe heart failure. This study was conducted at 19 centers and included 211 client-owned dogs with heart failure caused by mitral regurgitation (MR) due to acquired valvular disease or dilated cardiomyopathy (DCM). Dogs of various breeds, ages, and weights were included in the study. Replicates of 2 dogs each were formed, using separate allocation schedules for dogs with MR or DCM. One dog within each replicate received placebo tablets (vehicle tablets without enalapril) PO sid or bid, and the other dog received enalapril tablets at approximately 0.5 mg/kg sid or bid, based on individual need. In addition to the experimental drug, all dogs, except 1 in the placebo group, received furosemide; 73.3% of the dogs in the placebo group and 78.3% of those in the enalapril group received digoxin. Doses of enalapril or placebo were administered for approximately 28 days. In the placebo group, 68.6% of the dogs completed the study compared with 84.9% in the enalapril group; the difference between groups was significant (P < .01). Significantly (P < .01) more dogs in the placebo group compared with the enalapril group died or were removed from the study because of progression of heart failure. On day 28, all 14 clinical variables measured improved significantly (P < .01) in the enalapril group compared with the placebo group. Five dogs (3 from the placebo group and 2 from the enalapril group) had to be removed from the study as a result of azotemia.