Data extraction and risk of bias assessment
We collected data on study design, number of patients, age, gender, preoperative neurological symptom including syncope, stroke, hemiplegia, comatose state, Glasgow Coma Scale (GCS), and National Institutes of Health stroke scale (NIHSS), the time from onset of symptoms to operation, the operation data including cannulation, procedure (hemiarch replacement, HAR; partial arch replacement, PAR; total arch replacement, TAR), hypothermic cardiac arrest (HCA) time, temperature during HCA, cerebral perfusion (antegrade cerebral perfusion, ACP; retrograde cerebral perfusion, RCP), cross-clamp time (CCT), and cardiopulmonary bypass (CPB) time, the mortality rate, the neurological outcomes and follow-up.
The risk of bias was assessed at the study level using the Cochrane’s Collaboration Risk of Bias Tool [11]. Through six domains, this tool evaluates the risk of bias and categorizes each study as high-risk, low-risk, or unclear-risk of bias.