A ngiotensin-converting–enzyme
(ACE) inhibitors have been the cornerstone
of the treatment for heart failure
and a reduced ejection fraction for nearly 25
years, since enalapril was shown to reduce the
risk of death in two trials
Long-term treatment with enalapril decreased the relative risk of
death by 16% among patients with mild-to-moderate
symptoms
The effect of angiotensin-receptor
blockers (ARBs) on mortality has been
inconsistent,
and thus, these drugs are recommended
primarily for patients who have unacceptable
side effects (primarily cough) while receiving
ACE inhibitors.
Subsequent studies
showed that the use of beta-blockers and mineralocorticoid-
receptor antagonists, when added to
ACE inhibitors, resulted in incremental decreases
in the risk of death of 30 to 35% and 22 to 30%,
respectively
Neprilysin, a neutral endopeptidase, degrades
several endogenous vasoactive peptides, including
natriuretic peptides, bradykinin, and adrenomedullin.
Inhibition of neprilysin increases
the levels of these substances, countering the
neurohormonal overactivation that contributes
to vasoconstriction, sodium retention, and maladaptive
remodeling
Combined inhibition of
the renin–angiotensin system and neprilysin had
effects that were superior to those of either approach
alone in experimental studies
but in clinical trials, the combined inhibition of ACE
and neprilysin was associated with serious angioedema.
LCZ696, which consists of the neprilysin inhibitor
sacubitril (AHU377) and the ARB valsartan,
was designed to minimize the risk of serious
angioedema.
In small trials involving patients
who had hypertension or heart failure with
a preserved ejection fraction, LCZ696 had hemodynamic
and neurohormonal effects that were
greater than those of an ARB alone
We examined
whether the long-term effects of LCZ696
on morbidity and mortality were superior to those
of ACE inhibition with enalapril in patients
with chronic heart failure and a reduced ejection
fraction.