The Effect of Ramipril on Left Ventricular Mass, Myocardial Fibrosis, Diastolic Function, and Plasma Neurohormones in Maine Coon Cats with Familial Hypertrophic Cardiomyopathy without Heart Failure

Abstract

Background: Hypertrophic cardiomyopathy (HCM) is the most common heart disease of cats, resulting in left ventricular (LV) hypertrophy, myocardial fibrosis, and diastolic dysfunction.Hypothesis: Ramipril will reduce LV mass, improve diastolic function, and reduce myocardial fibrosis in cats with HCM without congestive heart failure (CHF).Animals: This prospective, blinded, placebo-controlled study included 26 Maine Coon and Maine Coon cross-bred cats with familial HCM but without CHF.Methods: Cats were matched for LV mass index (LVMI) and were randomized to receive ramipril (0.5 mg/kg) or placebo q24h for 1 year, with investigators blinded. Plasma brain natriuretic peptide (BNP) concentration, plasma aldosterone concentration, Doppler tissue imaging (DTI), and systolic blood pressure were measured at baseline and every 3 months for 1 year. Cardiac magnetic resonance imaging (cMRI) was performed to quantify LV mass and myocardial fibrosis by delayed enhancement (DE) cMRI at baseline and 6 and 12 months. Plasma angiotensin-converting enzyme (ACE) activity was measured on 16 cats 1 hour after PO administration.Results: Plasma ACE activity was adequately suppressed (97%) in cats treated with ramipril. LV mass, LVMI, DTI, DE, blood pressure, plasma BNP, and plasma aldosterone were not different in cats treated with ramipril compared with placebo (P 5 .85, P 5 .94, P 5 .91, P 5 .89, P 5 .28, P 5 .18, and P 5 .25, respectively).Conclusion: Treatment of Maine Coon cats with HCM without CHF with ramipril did not change LV mass, improve diastolic function, alter DE, or alter plasma BNP or aldosterone concentrations in a relevant manner.

Multicenter Evaluation of Plasma N‐Terminal Probrain Natriuretic Peptide (NT‐pro BNP) as a Biochemical Screening Test for Asymptomatic (occult) Cardiomyopathy in Cats

“…Cats diagnosed with asymptomatic (occult) cardiomyopathy (OCM) were also recruited from clients through cardiology specialty clinics. All cats were evaluated by echocardiography with simultaneous ECG from standard views according to accepted techniques . Variables of interest included left ventricular caudal wall thickness at end‐diastole (LVWd); interventricular septal thickness at end‐diastole (IVSd); left ventricular chamber dimension at end‐diastole (LVd); left ventricular chamber dimension at end‐systole (LVs); and left ventricular shortening fraction (%FS).…”

“…As such, its measurement contributes important information toward reducing cardiac morbidity, mortality, and medical costs . Increased natriuretic peptide concentrations have been detected in cats with symptomatic and asymptomatic heart disease, but its reliability to detect subclinical (occult) forms of myocardial diseases in cats remains to be clarified.…”

Disease Pathways and Novel Therapeutic Targets in Hypertrophic Cardiomyopathy

“…4,[67][68][69][70][71][72][73] Other pharmacological approaches to mitigating LVH include rapamycin (inhibiting the mammalian target of rapamycin -mTOR), which exhibits antihypertrophic properties in rodents. 74 In practice, derivatives or substitutes of such agents will likely be required because of their immunosuppressive effects.…”

The Effect of Atenolol on NT‐proBNP and Troponin in Asymptomatic Cats with Severe Left Ventricular Hypertrophy because of Hypertrophic Cardiomyopathy: A Pilot Study

“…Information regarding the management of HCM before the onset of heart failure is limited. Recent studies suggest that early intervention with an ACE inhibitor or spironolactone is not beneficial 8–10 . Consequently, the search continues for a drug that might be effective in slowing the progression of HCM.…”