Incremental risk of obstructive sleep apnea on cardiac surgical outcomes.

Aim: Obstructive sleep apnea (OSA) is not generally acknowledged as a perioperative risk factor. High incidence of Sleep disordered breathing has been noticed in patients with cardiovascular disease. The Sleep Heart Health Research Study Group found Apnea-Hypopnea indices (AHI) as modest as 1-10 to be associated with cardiovascular disease manifestations. Given the lack of data we chose to study the incremental risk of OSA in patients undergoing cardiac surgery.

Methods: We looked at 25 587 patients who underwent cardiac surgery at the Cleveland Clinic. Of these, 37 patients were also identified on the Cleveland Clinic Sleep center database as having OSA. Each of these 37 cases were propensity matched for multiple covariates with 5 controls within a distance of 0.001 units. An assumption was made that if the surgery was performed within two years of the diagnosis of OSA, the patient had OSA at the time of the surgery.

Results: Higher incidence of encephalopathy (p=0.008), postoperative infection (0.028) and increased ICU length of stay (p=0.031) were noted in the group with OSA after cardiac surgery. The difference in the rates of infection was mostly accounted for by the presence of mediastinitis (8.1% vs 1.6%). Differences in the rates of reintubation, tube time, and overall postoperative morbidity were not statistically significant.

Conclusions: | Increased risk for postoperative complications is suggested in patients with OSA undergoing cardiac surgery. This risk is underestimated on account of lack of awareness about the incidence of OSA in the general population and the cardiovascular population in particular, difficulties in clinical suspicion and diagnosis and limited use of polysomnography.