Rationale and Methods of a Randomized Trial Evaluating the Effect of Neprilysin Inhibition on Left Ventricular Remodelling

AIMS: In patients at high risk of heart failure following myocardial infarction (MI) as a result of residual left ventricular systolic dysfunction (LVSD), the angiotensin receptor neprilysin inhibitor sacubitril/valsartan may result in a greater attenuation of adverse left ventricular (LV) remodelling than renin angiotensin aldosterone system inhibition alone, due to increased levels of substrates for neprilysin with vasodilatory, anti-hypertrophic, anti-fibrotic, and sympatholytic effects. METHODS: We designed a randomized, double-blinded, active-comparator trial to examine the effect of sacubitril/valsartan to the current standard of care in reducing adverse LV remodelling in patients with asymptomatic LVSD following MI. Eligible patients were ≥3 months following MI, had an LV ejection fraction ≤40% as measured by echocardiography, were New York Heart Association functional classification I, tolerant of an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker at equivalent dose of ramipril 2.5 mg twice daily or greater, and taking a beta-blocker unless contraindicated or intolerant. Patients were randomized to sacubitril/valsartan (target dose 97/103 mg twice daily) or valsartan (target dose 160 mg twice daily). The primary endpoint will be change in LV end-systolic volume indexed for body surface area measured using cardiac magnetic resonance imaging over 52 weeks from randomization. Secondary endpoints include other magnetic resonance imaging-based metrics of LV remodelling, biomarkers associated with LV remodelling and neurohumoral activation, and change in patient well-being assessed using a patient global assessment questionnaire. CONCLUSIONS: This trial will investigate the effect of neprilysin inhibition on LV remodelling and the neurohumoral actions of sacubitril/valsartan in patients with asymptomatic LVSD following MI.