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

Study Objectives: We examined the prevalence of obstructive sleep apnea (OSA) among patients undergoing cardiac surgery and its impact on postoperative outcomes. Methods: 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. Results: 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 SpO(2) < 90% between AHI or LVEF groups, or by presence/absence of complications. Patients with any amount of TST with SpO(2) < 90% had greater BMI, longer OR tube time, and greater prevalence of prolonged intubation (p = 0.007, 0.035, 0.038, respectively). Conclusions: 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.