The Effects of Sacubitril/Valsartan Compared to Valsartan on LV Remodelling in Asymptomatic LV Systolic Dysfunction After MI

The objective of the present proposal is to obtain information, which is currently not available, on the cardiac effects of sacubitril/valsartan in patients with LVSD, better characterise the neurohumoral actions of sacubitril/valsartan and gather "proof-ofconcept", mechanistic, evidence in humans to support adoption of this new treatment in patients at high risk after myocardial infarction as a result of residual LVSD. Surprisingly, there is currently limited evidence about how sacubitril/valsartan works in humans. PARADIGM-HF was a large pragmatic mortality/morbidity trial with no mechanistic sub-studies and this is also true of a ongoing trial (PARADISE-MI) in acute myocardial infarction. Moreover, both trials either used or will use an ACE inhibitor (enalapril and ramipril, respectively), rather than an ARB as the active comparator for sacubitril/valsartan; use of valsartan in our study will allow us to precisely define the effects of neprilysin inhibition. A-type (or atrial) natriuretic peptide (ANP), C-type natriuretic peptide (CNP) and adrenomedullin are substrates for neprilysin and may play a role in the action of sacubitril/valsartan but have not been measured in existing clinical trials (in part because of the instability of these peptides and unfeasibility of measuring them in multi-centre, multi-national trials). Indeed, ANP and CNP are more specific substrates for neprilysin than BNP. As has been mentioned above, cardiac fibrosis appears to be important in the process of LV remodelling in patients with asymptomatic LVSD and the development of HF-REF and is reflected in circulating biomarkers which may be influenced by sacubitril/valsartan