The incidence, risk factors and outcomes of impaired cerebral autoregulation in aortic arch surgery: a single-center, retrospective cohort study

Background: ː Impairment of cerebral autoregulation (CA) has been observed in patients undergoing cardiopulmonary bypass (CPB), but little is known about its risks and associations with outcomes. The objective of this study was to analyze the incidence and risks 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 One hundred fifteen four adult 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 (rScO 2 ) and mean blood pressure (MAP). Pre- and intraoperative factors were tested for independent association with impaired CA. Postoperative outcomes were compared between patients with normal and impaired CA.Resultsː In our 154 patients, 46(29.9%) developed new-onset impaired CA after CPB with MHCA. Multivariate analysis revealed a prolonged low rScO 2 (rScO 2 <55%) independently associated with onset of impaired CA, and receiver operating charactoristic curve showed a cutoff value at 40 min (sensitivity, 89.5%; specificity, 68.0%). Compared with normal CA patients, those with impaired CA showed a significantly higher rates of in-hospital mortality and postoperative complications.Conclusionː Prolonged low rScO 2 (rScO 2 <55%) during aortic arch surgery was closely related to onset of impaired CA. Impaired CA remained associated with the increased rates of postoperative complications and in-hospital mortality. Trial registration ChiCTR1800014545 with registered date 20/01/2018.