Author + information
- Received June 26, 2009
- Revision received August 26, 2009
- Accepted August 30, 2009
- Published online October 27, 2009.
- Joshua D. Gottlieb, AM⁎,
- Alan R. Schwartz, MD†,
- Joanne Marshall‡,
- Pamela Ouyang, MBBS†,
- Linda Kern†,
- Veena Shetty, MPH§,
- Maria Trois†,
- Naresh M. Punjabi, MD, PhD†,
- Cynthia Brown, MD∥,
- Samer S. Najjar, MD¶ and
- Stephen S. Gottlieb, MD‡,⁎ ()
- ↵⁎Reprint requests and correspondence:
Dr. Stephen S. Gottlieb, University of Maryland, 22 South Greene Street, Baltimore, Maryland 21201
Objectives This study was conducted to evaluate whether brain (B-type) natriuretic peptide (BNP) changes during sleep are associated with the frequency and severity of apneic/hypopneic episodes, intermittent arousals, and hypoxia.
Background Sleep apnea is strongly associated with heart failure (HF) and could conceivably worsen HF through increased sympathetic activity, hemodynamic stress, hypoxemia, and oxidative stress. If apneic activity does cause acute stress in HF, it should increase BNP.
Methods Sixty-four HF patients with New York Heart Association functional class II and III HF and ejection fraction <40% underwent a baseline sleep study. Five patients with no sleep apnea and 12 with severe sleep apnea underwent repeat sleep studies, during which blood was collected every 20 min for the measurement of BNP. Patients with severe sleep apnea also underwent a third sleep study with frequent BNP measurements while they were administered oxygen. This provided 643 observations with which to relate apnea to BNP. The association of log BNP with each of 6 markers of apnea severity was evaluated with repeated measures regression models.
Results There was no relationship between BNP and the number of apneic/hypopneic episodes or the number of arousals. However, the burden of hypoxemia (the time spent with oxygen saturation <90%) significantly predicted BNP concentrations; each 10% increase in duration of hypoxemia increased BNP by 9.6% (95% confidence interval: 1.5% to 17.7%, p = 0.02).
Conclusions Hypoxemia appears to be an important factor that underlies the impact of sleep abnormalities on hemodynamic stress in patients with HF. Prevention of hypoxia might be especially important for these patients.
This study was supported by grant #R01 HL071506from the National Heart, Lung and Blood Institute, National Institutes of Health(NIH), and by grant #M01-RR02719from the National Center for Research Resources(NCRR), a component of NIH, and NIH Roadmap for Medical Research.
Its contents are solely the responsibility of the authors and do not necessarily represent the official view of the NCRR or NIH. Information on NCRR is available at http://www.ncrr.nih.gov/. Information on Re-engineering the Clinical Research Enterprise can be obtained from http://nihroadmap.nih.gov/clinical research/overview-translational.asp.
This study was supported, in part, by the Intramural Research Program of the National Institute on Aging, NIH, a portion of which was through a Research and Development Contract with MedStar Research Institute. The BNP assays were provided by Biosite, Inc., San Diego, California.
Drs. Najjar and Gottlieb contributed equally to this paper.
- Received June 26, 2009.
- Revision received August 26, 2009.
- Accepted August 30, 2009.
- American College of Cardiology Foundation