Backgroundː Impairment of cerebral autoregulation (CA) has been observed in patients undergoing cardiopulmonary bypass (CPB), but little is known about its occurrence and associations with outcomes. The objective of this study was to analyze the occurrence of impaired CA, based on cerebral oximetry index (COx), in patients undergoing total aortic arch replacement with CPB and moderate hypothermic circulatory arrest (MHCA). We also evaluated the association between impaired CA and patient outcomes.

Methodsː Sixty-four patients who underwent total aortic arch replacement with stented elephant trunk implantation under CPB and MHCA at our hospital were retrospectively analyzed. Patients were defined as having new-onset impaired CA if post-CPB COx > 0.3, calculated based on a moving linear correlation coefficient between regional cerebral oxygen saturation (rScO₂) and mean blood pressure (MAP). Postoperative complication and in-hospital mortality were compared between patients with normal and impaired CA.

Resultsː Of the 64 patients, 19(29.7%) developed new-onset impaired CA after CPB with MHCA. Compared with normal CA patients, those with impaired CA showed a significantly longer duration of rScO₂ <55%, and significantly higher rates of in-hospital mortality and postoperative complications (acute kidney injury, delirium, mechanical ventilation > 24h, and respiratory infection).

Conclusionsː In our cohort, 29.7% of patients who underwent total aortic arch replacement developed new-onset impaired CA after CPB with MHCA. Impaired CA might be associated with significantly increased rates of postoperative complications and in-hospital mortality.