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Effect of Carvedilol on Survival in
Severe
Congestive Heart Failure
Congestive heart failure affects about 5 million Americans, most 65
years of age and older. Heart failure is the leading cause of
hospitalization in persons in the Medicare generation.
Although Beta-Blocking agents have been shown to reduce the risk of
hospitalization and death in patients with mild-to-moderate heart failure,
little is known about the effect or safety of these drugs in severe heart
failure. Beta-blockers have usually been avoided in patients with severe
heart failure, because of the concern that they may worsen the condition.
Results of a study reported in the May 31, 2001 New England Journal of
Medicine reports that Carvedilol, as compared with a placebo, reduces
risk of death by 35% in patients with severe congestive heart failure and
cut the combined risk of death or hospitalization by 24%.
The study named The Carvedilol Prospective Randomized Cumulative
Survival Study enrolled 2289 patients with dyspnea or fatigue at rest or
on minimal exertion and with a left ventricular ejection fraction of less
than 25%. They were randomly assigned, 1133 to placebo and 1156 patients
to treatment with Carvedilol for a period of 10.4 months, during which
time their standard therapy for heart failure was continued. The study
excluded patients with marked fluid retention, clinically significant
renal dysfunction, hypotension or the need for intravenous vasodilators or
inotropic drugs. On the recommendation of the data and safety monitoring
board, the study was stopped early because of the finding that Carvedilol
had a significantly positive effect on survival rates.
Treating congestive heart failure patients with beta-blockers requires
careful monitoring because the patient may initially do worse before doing
better. However the results of the study demonstrates good news, that even
the sickest of the heart failure patients can improve if they are willing
to work through the difficult period. It takes about three months of
treatment with Carvedilol before benefits are apparent to the physician
and the patient. The initial increase in symptoms may include a lower
heart rate, lower blood pressure and increase in fluid retention.
Medications, such as ACE inhibitors, diuretics and Digoxin are frequently
adjusted until symptoms improve and the full dose of Carvedilol is
achieved. If the patient is willing to tough out the difficult period,
their failing heart usually begins to function more efficiently.
The results of this study demonstrate that long-term treatment with
Carvedilol has substantial benefits in patients with severe, but not
extremely severe, chronic heart failure. The addition of Carvedilol to
conventional therapy decreased the rate of death by 35 percent and the
rate of death or hospitalization by 24 percent. These benefits were
apparent regardless of age, sex, cause of heart failure, left ventricular
ejection fraction, or recent history with respect to hospitalization and
were seen even in patients with a history of recent recurrent cardiac
decompensation or severely depressed cardiac function. Finally, treatment
with Carvedilol was well tolerated; fewer patients in the Carvedilol group
than in the placebo group required discontinuations of treatment because
of adverse effects or for other reasons. |
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