Context Although -blockers improve symptoms and survival
in adults with heart failure, little is known about these medications
in children and adolescents.
Objective To prospectively evaluate the effects of carvedilol
in children and adolescents with symptomatic systemic ventricular
systolic dysfunction.
Design, Setting, and Participants A multicenter, randomized,
double-blind, placebo-controlled study of 161 children and adolescents
with symptomatic systolic heart failure from 26 US centers.
In addition to treatment with conventional heart failure medications,
patients were assigned to receive placebo or carvedilol. Enrollment
began in June 2000 and the last dose was given in May 2005 (each
patient received medication for 8 months).
Interventions Patients were randomized in a 1:1:1 ratio
to twice-daily dosing with placebo, low-dose carvedilol (0.2
mg/kg per dose if weight <62.5 kg or 12.5 mg per dose if
weight 62.5 kg), or high-dose carvedilol (0.4 mg/kg per dose
if weight <62.5 kg or 25 mg per dose if weight 62.5 kg) and
were stratified according to whether each patient's systemic
ventricle was a left ventricle or not.
Main Outcome Measures The primary outcome was a composite
measure of heart failure outcomes in patients receiving carvedilol
(low- and high-dose combined) vs placebo. Secondary efficacy
variables included individual components of this composite,
echocardiographic measures, and plasma b-type natriuretic peptide
levels.
Results There was no statistically significant difference
between groups for the composite end point based on the percentage
of patients who improved, worsened, or were unchanged. Among
54 patients assigned to placebo, 30 improved (56%), 16 worsened
(30%), and 8 were unchanged (15%); among 103 patients assigned
to carvedilol, 58 improved (56%), 25 worsened (24%), and 20
were unchanged (19%). The rates of worsening were lower than
expected. The odds ratio for worsened outcome for patients in
the combined carvedilol group vs the placebo group was 0.79
(95% CI, 0.36-1.59;
P = .47). A prespecified subgroup
analysis noted significant interaction between treatment and
ventricular morphology (
P = .02), indicating a possible
differential effect of treatment between patients with a systemic
left ventricle (beneficial trend) and those whose systemic ventricle
was not a left ventricle (nonbeneficial trend).
Conclusions These preliminary results suggest that carvedilol
does not significantly improve clinical heart failure outcomes
in children and adolescents with symptomatic systolic heart
failure. However, given the lower than expected event rates,
the trial may have been underpowered. There may be a differential
effect of carvedilol in children and adolescents based on ventricular
morphology.
Trial Registration clinicaltrials.gov Identifier:
NCT00052026 相似文献