Renal Outcomes After Surgery for Acute Type A Aortic Dissection: Association of Intraoperative Cerebral Near-Infrared Spectroscopy with Acute Kidney Injury

Background: Acute kidney injury (AKI) is common after acute type A aortic dissection (ATAAD) repair. We investigated whether intraoperative cerebral near-infrared spectroscopy (NIRS) was associated with postoperative AKI. Methods: This retrospective single-center study included 288 adults undergoing open repair of acute aortic dissection with hypothermic circulatory arrest between 2015 and 2023, predominantly for ATAAD, including seven non-A non-B dissections. Bilateral cerebral NIRS was recorded at five predefined time points. AKI was defined using modified creatinine/renal replacement therapy-based KDIGO criteria. Multivariable logistic regression included cardiopulmonary bypass (CPB) duration, DeBakey type I, and anatomical renal artery involvement; additional adjustment examined baseline NIRS. Results: AKI occurred in 181 patients (62.8%), including stage 3 in 94 (32.6%). Left-sided NIRS was lower with AKI before CPB (69% vs. 73%, p = 0.020) and five minutes before CPB completion (72% vs. 75%, p = 0.004). In multivariable analysis (n = 273), CPB duration (OR 1.016/minute, 95% CI 1.009–1.022, p < 0.001), renal artery involvement (OR 2.041 per additional artery, 95% CI 1.167–3.569, p = 0.012), and left-sided NIRS near CPB completion (OR 0.965/%, 95% CI 0.938–0.992, p = 0.011) were associated with AKI. The NIRS association attenuated after baseline adjustment (OR 0.976, 95% CI 0.946–1.006, p = 0.117). In-hospital mortality was higher with AKI (27.6% vs. 7.5%, p < 0.001). Conclusions: AKI affected nearly two thirds of patients undergoing ATAAD repair. Lower left-sided cerebral NIRS near CPB completion was associated with AKI after adjustment for bypass duration and renal artery involvement, but the association attenuated after baseline adjustment. This exploratory finding requires prospective validation.