The Effects of Sacubitril/Valsartan Compared to Valsartan on Left Ventricular Remodelling in Asymptomatic Left Ventricular Systolic Dysfunction After Myocardial Infarction: a Randomised, Double-blinded, Active-comparator, Cardiac-MR Based Trial

Prior to reperfusion therapy, the major therapeutic breakthrough in myocardial infarction was the demonstration that ACE inhibitors or ARBs, given to prevent adverse "remodelling" (progressive dilatation and decline in systolic function) in high risk patients, reduced the likelihood of developing heart failure and the risk of death. The neurohumoral systems which are activated in patients after myocardial infarction (and in heart failure) are not all harmful and some endogenous systems may be protective. The best recognised of these is the natriuretic peptide system.

A- and B-type natriuretic peptides are secreted by the heart when it is stressed and these peptides promote vasodilation (reducing left ventricular wall stress), stimulate renal sodium and water excretion (i.e. antagonising the retention of salt and water characterising heart failure) and inhibit pathological growth i.e. hypertrophy and fibrosis (key components of the adverse left ventricular remodelling that occurs after infarction and in heart failure).The augmentation of plasma levels of endogenous natriuretic peptides can be achieved through inhibition of neutral endopeptidase, also known as neprilysin (NEP), which is responsible for the breakdown of natriuretic peptides. Recently, the addition of neprilysin inhibition to blockade of the RAAS (using sacubitril/valsartan), compared with RAAS blockade alone, reduced the risk of heart failure hospitalisation and death in patients with HF-REF. These exciting findings may lead to a new approach to the treatment of heart failure, with an angiotensin receptor neprilysin inhibitor (ARNI) replacing an ACE inhibitor as one of the fundamental treatments for this condition. We believe that the same approach may be beneficial in highrisk survivors of myocardial infarction. Recently, sacubitril/valsartan was shown to ameliorate adverse left ventricular remodelling in an experimental model of acute myocardial infarction. The objective of the present proposal is to gather "proof-ofconcept", mechanistic, evidence in humans to support adoption of this new approach in patients at high risk after myocardial infarction as a result of residual left ventricular systolic dysfunction.