Causal risk factors for stroke, delirium, and mortality after elective and urgent open aortic arch surgery for older adults.

In this exploratory study, we identified causal risk factors in open aortic arch surgery involving antegrade selective cerebral perfusion (ASCP) for postoperative deficits. A retrospective study analyzing open aortic arch surgery involving ASCP data. Causal discovery algorithms can detect how variables in a data set are causally related, and with their aid, we explored whether possible risk factors among preoperative variables, such as renal function and chronic lung disease, are causally related to postoperative deficits such as cerebrovascular accident, delirium, and mortality. Middle cerebral artery velocity (MCAv), a proxy variable for cerebral blood flow, was also included as a risk factor since previous studies have found an association between postoperative neurological deficits and lower MCAv. We found in our study population (n = 142, 46% female, median age 68 [IQR 60,73]) that poor renal function affected mechanical ventilation >24 h with a probability of 0.64 and rethoracotomy with a probability of 0.56, whereas rethoracotomy was causally related to mortality. Moreover, we found evidence that prior cardiac surgery is causally linked to mortality. Age was not found to be directly related to the adverse outcomes in the study population. We identified renal function as a causal risk factor for short-term adverse outcomes, including mortality. For clinical practice, these variables warrant further attention in the decision-making process. Further work could explore whether interventions to improve renal function may positively impact adverse outcomes after aortic arch surgery.