The Effects of Unilateral Cerebral Perfusion Under Mild Hypothermia

Abstract

DeBakey type I aortic dissection requires circulatory arrest during arch reconstruction, putting the brain at risk. In resource-limited centers, deep hypothermia can exacerbate coagulopathy and lead to increased bleeding. This study compares outcomes between mild and moderate hypothermia under unilateral cerebral perfusion (UCP).Retrospective analysis of 60 patients who underwent modified Bentall procedures with hemiarch replacement under UCP between 2014 and 2024. Patients were divided into two groups: mild hypothermia (mH, 32°C; n = 40) and moderate hypothermia (MH, 24°C; n = 20). Exclusion criteria included bilateral cerebral perfusion, additional procedures (e.g., total arch replacement, bypass surgery), preexisting neurological or renal conditions, and incomplete datasets. Neurological events, blood loss, transfusion requirements, acute kidney injury (AKI), and mortality were assessed.Neurological outcomes (permanent neurological dysfunction and transient neurological dysfunction) were comparable in both groups (20% each). The mH group had significantly lower blood loss (787 vs. 1,183 mL), reduced red blood cell transfusion (200 vs. 828 mL), and less fresh frozen plasma use (259.5 vs. 882 mL). The mH group also had lower rates of AKI (15 vs. 30%), rethoracotomy (10 vs. 22.5%), and infections (10 vs. 20%). Mortality was 20% (mH) versus 35% (MH).Mild hypothermia under UCP provides cerebral protection comparable to moderate hypothermia while reducing coagulopathy, transfusion needs, and complications-particularly relevant for centers in resource-limited countries.