D97-05 Occurrence of Postoperative Acute Kidney Injury in Patients With Sleep Apnea After Coronary Artery Bypass Grafting

Rationale Postoperative acute kidney injury (AKI) is a frequent and serious complication following coronary artery bypass grafting (CABG). Sleep apnea, which is highly prevalent in this population, may contribute to renal dysfunction through intermittent hypoxia, sympathetic activation, and systemic inflammation. This study tested the hypothesis that sleep apnea is associated with an increased risk for postoperative AKI and its subtypes in patients undergoing elective CABG. Methods In this prospective cohort study (CONSIDER-AF, NCT02877745), 746 consecutive patients undergoing elective CABG between 2016 and 2024 were included (mean age 66 ± 8 years; 86% male). Preoperative sleep apnea was assessed by overnight polygraphy and categorized as none/mild (apnea-hypopnea index [AHI] <15/h), moderate (15-30/h), or severe (>30/h). AKI within the first 7 postoperative days was defined according to KDIGO criteria. Logistic regression models accounting for age, sex, body mass index, arterial hypertension, diabetes mellitus, smoking status, preoperative creatinine, and heart failure were used to evaluate associations between sleep apnea and postoperative AKI. Results Moderate and severe sleep apnea were present in 26% and 17% of patients, respectively. Overall, 26% of patients developed postoperative AKI, with a stepwise increase across sleep apnea severity (20%, 30%, and 40%, p < 0.001). Among these, de novo AKI (i.e., AKI in patients with previously normal renal function) occurred in 11%, 17%, and 17% across none/mild, moderate, and severe sleep apnea groups (p = 0.035), while acute-on-chronic AKI occurred in 10%, 15%, and 24%, respectively (p = 0.001). In multivariable regression, sleep apnea (AHI≥15/h) was associated with the occurrence of postoperative AKI (OR 1.75 [95% CI 1.20-2.56], p = 0.004). In contrast to non-specific hypoxemic burden, hypoxemic burden associated with cyclic desaturations (T90desaturation %), also correlated with AKI risk (fully adjusted OR 1.02 [1.00-1.04], p = 0.041). Patients with AKI had longer ICU stays (4.9±9.4 vs. 2.4±2.2 days, p < 0.001) and higher total hospitalization rate (17.6±15.5 vs. 11.0±6.2 days, p < 0.001). Conclusions Sleep apnea is common among patients undergoing CABG and is independently associated with postoperative AKI, including both de novo and acute-on-chronic forms of AKI. Sleep apnea associated with repetitive oxygen desaturations appear to play a key pathophysiological role. Whether preoperative detection and management of sleep apnea may represent a modifiable target to reduce renal complications after cardiac surgery merits further investigation.