Evidence of Global Warming: A Meta-Analysis of Temperature Management in Aortic Arch Surgery

Objectives: Treatment of aortic pathologies involving the distal ascending aorta, aortic arch, and descending aorta remains a complex and challenging procedure. Appropriate management is important to achieve satisfactory outcome. Surgical management aims to reduce the time of circulatory arrest. The optimal level of hypothermia is still a matter of debate. The present meta-analysis shows the influence of different temperature levels on mortality and morbidity following aortic arch surgery. Methods: We performed a meta-analysis of published data between January 2000 and March 2020 based on a literature research. 120 studies were included with a total of 32 323 patients divided into three different groups of systemic hypothermia (temperature group 1: ≥ 25 °C, temperature group 2: 25-20°C, temperature group 3: ≤ 20°C) were used for statistical analysis. Results: Early mortality was lowest in temperature group 1 compared to group 2 (OR = 1.42; 95% CI, 1.09-1.85; p=0.01) and group 3 (OR = 1.74; 95% CI, 1.20–2.52; p=0.003). Perioperative stroke appeared to be less frequently in temperature group 1 versus group 2 (OR = 1.48; 95% CI, 1.20-1.82; p=0.0002) and group 3 (OR = 1.61; 95% CI, 1.19 - 2.18; p=0.002). Similar results are obtained concerning new renal insufficiency (group 1 versus group 2: OR = 1.20; 95% CI, 0.91-1.57, p=0.19; group 1 versus 3: OR = 0.94; 95% CI, 0.67 - 1.32, p=0.73) and re-exploration for bleeding (group 1 versus group 2: OR = 1.10; 95% CI, 0.80-1.53, p=0.55; group 1 versus group 3: OR = 1.92; 95% CI, 1.26 - 2.94, p=0,0025). Conclusions: We observed that moderate level of hypothermia during circulatory arrest reduced the incidence of early mortality. Most dreaded neurologic complications occurred less frequently in TG 1. In contrast there was no difference with regards with new onset of renal failure which is commonly accepted as a reliable marker of the quality of visceral organ protection.