Continuous Positive Airway Pressure for Heart Failure Patients With Central Sleep Apnea - CANPAP
The goal of the trial was to evaluate treatment with continuous positive airway pressure (CPAP) among heart failure patients with central sleep apnea.
Patients Screened: 727
Patients Enrolled: 258
Mean Follow Up: Two years
Mean Patient Age: Mean age 63 years
Mean Ejection Fraction: Baseline ejection fraction 24.5%
Age 18-79, heart failure, ejection fraction <40%, and central sleep apnea despite optimal medical therapy
Death or heart transplantation
Apnea hypopnea index, quality of life
Patients were randomized to nocturnal CPAP (n=128) titrated as tolerated to 10 cmH2O or to no CPAP (n=130).
CPAP was used an average of four hours per day during the trial. Average sleep time was 304 minutes in the CPAP group and 308 minutes in the control group. Apnea hypopnea index at baseline was 40 apneas/hour.
The trial was discontinued early after the event rate for death or transplantation observed in the trial was too low to detect a difference based on the expected event rate used to determine the sample size for the trial. There was no difference in the primary endpoint of death or transplantation (n=32 each, p=0.54). There was also no difference in the frequency of hospitalization between groups (0.56 vs 0.61 hospitalizations per patient year, p=0.45).
At 12-week follow-up, the CPAP group had larger decreases in apnea hypopnea index (from 39.7 to 18.6 apneas/hour in the CPAP group, p<0.001) and norepinephrine (from 3.0 to 2.1 pmol/l, p=0.014), and higher mean nocturnal oxygen saturation (from 93.2 to 94.9%, p<0.001) and ejection fraction (from 24.8% to 27.3%, p<0.05) than the control group. There were no differences in quality of life or exercise duration.
Among heart failure patients with central sleep apnea, use of CPAP was not associated with reductions in death or need for transplantation by two years compared with control patients.
Central sleep apnea has been shown to increase the risk of death in heart failure patients. The present study is the first randomized trial of clinical event outcomes with use of CPAP for the treatment of central sleep apnea among heart failure patients. Despite some beneficial findings in apnea hypopnea index, norepinephrine, oxygen saturation, and ejection fraction, the overall clinical event rate was much lower than expected, prompting early discontinuation of the trial.
Bradley TD, et al. Continuous Positive Airway Pressure for Central Sleep Apnea and Heart Failure. N Engl J Med 2005;353:2025-33.
Presented by Dr. T. Douglas Bradley at the March 2005 ACC Annual Scientific Session, Orlando, FL.
Keywords: Quality of Life, Continuous Positive Airway Pressure, Sleep Apnea, Central, Heart Failure, Norepinephrine, Oxygen, Hospitalization
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