Levels of hypothermia and clinical outcomes in acute type a aortic dissection surgery with circulatory arrest and antegrade cerebral perfusion: A systematic review and meta-analysis

ObjectivesIn acute type A aortic dissection (ATAAD) surgery requiring hypothermic circulatory arrest (HCA), substantial variation persists in cooling strategies, and the optimal target temperature before circulatory arrest remains debated. The objective of this study was to evaluate clinical outcomes associated with different hypothermia strategies in ATAAD surgery performed under HCA with antegrade cerebral perfusion (ACP).MethodsThis review followed PRISMA guidelines and a registered PROSPERO protocol. Comprehensive database searches identified comparative studies of hypothermia levels during ATAAD repair with ACP. After screening and quality assessment, data were extracted for meta-analysis using random-effects modeling, evaluating mortality, postoperative stroke, and the need of postoperative dialysis.ResultsThe search yielded 11 eligible studies comprising 5996 patients. Most were observational and assessed mild-moderate temperature strategies. Meta-analysis showed reduced mortality and dialysis with warmer hypothermia, while the rates of postoperative stroke were similar. Heterogeneity was low except for postoperative dialysis, and publication bias was minimal to moderate across outcomes.ConclusionAcross all evaluated outcomes, deeper hypothermia did not demonstrate superiority over warmer strategies regarding in-hospital mortality, postoperative stroke, or acute kidney failure requiring dialysis. A definitive optimal temperature threshold for ATAAD surgery requiring HCA and ACP remains to be established.