Every Day is Heart Failure Awareness Day.
As you are aware, Heart Failure (HF) is the only major cardiovascular
disorder that is increasing in incidence and prevalence. This is due
in part to the aging population but as well to the increasing prevalence
and poor control of CHF precursors such as hypertension, diabetes, hyperlipidemia,
smoking and LVH. Approximately 1.5 - 2 % of the population have Heart
Failure and the prevalence increases to 6 -10 % of the population >
65 years old. Heart Failure is the leading cause of hospitalization
in the elderly and a frequent cause of death. Asymptomatic LV
(left ventricular) dysfunction is even more common and is often unrecognized.
Clinical trials have shown average annual mortality rates in stable
Heart Failure patients of around 10% with a 50% five-year survival rate.
Intervention with ACE inhibitors, such as the SOLVD
treatment arm [1] (clinical CHF and LVEF <
35 %; enalapril 2.5-20 mg./day) showed a 16% relative reduction in mortality
over a 41 month period. In the SOLVD
prevention arm [2] (patients with similar EFs
but minimal symptoms) ACE inhibitors showed a significant reduction
in the combined end-point of new heart failure and cardiovascular mortality
(relative risk reduction 20%). In the RALES
Trial [3], spironolactone, an aldosterone receptor
blocker, when added to ACE-inhibitor/diuretic/+/- digoxin in stable
Class III-IV CHF/LVEF < 35%, has shown an 11% absolute (ARR) and
30% relative risk reduction (RRR) for death in HF patients. The addition
of beta-blocker therapy to standard triple therapy for HF (digoxin,
diuretic and ACE inhibitor) such as in the U.S.
Carvedilol Trials [4] (LVEF < 35%; carvedilol
12.5-100mg/day) have shown a further 65% RRR in CV mortality (7.8% to
3.2 % ARR) in patients with NYHA class II-IV symptomatic HF. Carvedilol
has also been shown to produce a dose related increase in LVEF which
averaged 8% and to lead to a 27% relative risk reduction in cardiovascular
hospitalizations. Similar benefits were obtained in other trials of
beta-blockers in Heart Failure (MERIT
[5] -metoprolol and CIBIS
II [6] - bisoprolol).
The recent ICES Atlas of Cardiovascular Health and Services in Ontario
has demonstrated an astounding 33% annual mortality for patients hospitalized
for HF over the years 1994-1997. This discrepancy in outcomes between
clinical trials and clinical reality may in part be attributable to
patient selection in the clinical trials, but nevertheless there is
a huge care gap that must be overcome. Components of that care gap include: