Prevalence of Undetected Sleep Apnea in Patients Undergoing Cardiovascular Surgery and Impact on Postoperative Outcomes

Oct 20, 2015

as seen in Journal of Clinical Sleep Medicine, Oct 2015, Vol 11, Number 10

Nancy Foldvary-Schaefer, DO, MS1; Roop Kaw, MD2; Nancy Collop, MD3; Noah D. Andrews, RPSGT1; James Bena, MS4; Lu Wang, MS4; Tracey Stierer, MD5; Marc Gillinov, MD6; Matt Tarler, PhD7; Hani Kayyali, MBA, MS7

1Cleveland Clinic Sleep Disorders Center, Cleveland, OH; 2Cleveland Clinic Department of Hospital Medicine and Anesthesiology Outcomes Research, Cleveland, OH; 3Emory Sleep Disorders Center, Atlanta, GA; 4Cleveland Clinic Quantitative Health Sciences, Cleveland, OH; 5Johns Hopkins Department of Anesthesiology, Baltimore, MD; 6Cleveland Clinic Department of Cardiac and Thoracic Surgery, Cleveland, OH; 7Cleveland Medical Devices Inc., Cleveland, OH

Study Objectives

We examined the prevalence of obstructive sleep apnea (OSA) among patients undergoing cardiac surgery and its impact on postoperative outcomes.


Subjects were recruited from inpatient cardiovascular surgery units at two tertiary care centers. Crystal Monitor 20-H recorded polysomnograms preoperatively. Regression analyses were performed to explore associations between OSA using different apnea-hypopnea index (AHI) cutoffs and postoperative outcomes adjusting for key covariates. Prevalence of postoperative outcomes was compared among groups defined by AHI and left ventricle ejection fraction (LVEF) median cutoffs.


Of 107 participants, the AHI was ≥ 5 in 79 (73.8%), ≥ 10 in 63 (58.9%), ≥ 15 in 51(47.7%), and ≥ 30 in 29 (27.1%). Patients with AHI ≥ 15 had significantly lower LVEF (p < 0.001). Logistic regression analyses with OSA cutoffs as above adjusting for age, gender, race, BMI, and LVEF found no significant increase in odds for any postoperative outcomes. No significant differences were found in %Total sleep time (TST) with SpO2 < 90% between AHI or LVEF groups, or by presence/absence of complications. Patients with any amount of TST with SpO2 < 90% had greater BMI, longer OR tube time, and greater prevalence of prolonged intubation (p = 0.007, 0.035, 0.038, respectively).


OSA is highly prevalent in patients undergoing cardiovascular surgery. It could not be shown that OSA was significantly associated with adverse postoperative outcomes, but this may have been due to an insufficient number of subjects. AHI ≥ 15 was associated with lower LVEF. Larger samples are required to explore the impact of OSA on key postoperative outcomes that have clinical and economic importance in the care of cardiovascular surgery populations.


A commentary on this article appears in this issue on page 1081.


Foldvary-Schaefer N, Kaw R, Collop N, Andrews ND, Bena J, Wang L, Stierer T, Gillinov M, Tarler M, Kayyali H. Prevalence of undetected sleep apnea in patients undergoing cardiovascular surgery and impact on postoperative outcomes. J Clin Sleep Med 2015;11(10):1083–1089.