ABSTRACT Introduction: Lower body perfusion (LBP) is a technique used to provide blood perfusion to distal organs and spinal cord during circulatory arrest. However, the effect of LBP on the prognosis of aortic arch surgery, especially on postoperative renal function, remains unclear. Methods: A total of 304 patients with acute type A aortic dissection who underwent total aortic arch replacement combined with frozen elephant trunk implantation between May 2016 and December 2021 were retrospectively analyzed. The patients were divided into LBP group (group L, n=85) and non-LBP group (group NL, n=219). Routine lower body circulatory arrest was applied during operation in group NL, and antegrade LBP combined was applied during operation in group L. Perioperative data were recorded. Propensity score matching was used for statistical analysis. Results: After propensity score matching, 85 pairs of patients were successfully matched. Two groups significantly differed in circulatory arrest time (six minutes vs. 30 minutes, P=0.000), cross-clamping time (101 minutes vs. 92 minutes, P=0.010), minimum nasopharyngeal temperature (29.4ºC vs. 27.2ºC, P=0.000), and highest lactate value during cardiopulmonary bypass (2.3 μmol/L vs. 4.1 μmol/L, P=0.000). Considering the postoperative indicators, the drainage volume (450 mL vs. 775 mL, P=0.000) and the incidence of level I acute kidney injury (23.5% vs. 32%, P=0.046) in group L was lower than those in group NL. Conclusion: LBP resulted as a safe and feasible approach in aortic arch surgery, as it could significantly shorten the circulatory arrest time, which might reduce the incidence of postoperative level I acute kidney injury.

ABSTRACT Introduction: Lower body perfusion (LBP) is a technique used to provide blood perfusion to distal organs and spinal cord during circulatory arrest. However, the effect of LBP on the prognosis of aortic arch surgery, especially on postoperative renal function, remains unclear. Methods: A total of 304 patients with acute type A aortic dissection who underwent total aortic arch replacement combined with frozen elephant trunk implantation between May 2016 and December 2021 were retrospectively analyzed. The patients were divided into LBP group (group L, n=85) and non-LBP group (group NL, n=219). Routine lower body circulatory arrest was applied during operation in group NL, and antegrade LBP combined was applied during operation in group L. Perioperative data were recorded. Propensity score matching was used for statistical analysis. Results: After propensity score matching, 85 pairs of patients were successfully matched. Two groups significantly differed in circulatory arrest time (six minutes vs. 30 minutes, P=0.000), cross-clamping time (101 minutes vs. 92 minutes, P=0.010), minimum nasopharyngeal temperature (29.4ºC vs. 27.2ºC, P=0.000), and highest lactate value during cardiopulmonary bypass (2.3 μmol/L vs. 4.1 μmol/L, P=0.000). Considering the postoperative indicators, the drainage volume (450 mL vs. 775 mL, P=0.000) and the incidence of level I acute kidney injury (23.5% vs. 32%, P=0.046) in group L was lower than those in group NL. Conclusion: LBP resulted as a safe and feasible approach in aortic arch surgery, as it could significantly shorten the circulatory arrest time, which might reduce the incidence of postoperative level I acute kidney injury.

Resumo Introdução e objetivos Os mecanismos de neurotoxicidade dos anestésicos locais são complexos. A apoptose e a autofagia são mecanismos altamente organizados que mantêm a homeostase celular durante o estresse. Estudos revelam que a ativação da autofagia atua como mecanismo de proteção in vitro. Não está claro se a autofagia também desempenha essa função in vivo. O objetivo deste estudo foi analisar o papel da autofagia na neurotoxicidade induzida por anestésico local e esclarecer o mecanismo dessa neurotoxicidade utilizando um modelo de injeção intratecal em ratos. Métodos Dezoito ratos Sprague‐Dawley machos adultos saudáveis foram divididos aleatoriamente em três grupos. Antes de receber a injeção intratecal de bupivacaína a 1%, cada rato recebeu injeção intraperitoneal de veículo ou rapamicina (1 mg.kg‐1) uma vez ao dia durante 3 dias. As alterações patológicas foram examinadas por coloração com Hematoxilina e Eosina (HE). A apoptose foi analisada por coloração com o método dUTP Nick‐End Labeling (TUNEL) mediado por TdT. A expressão de caspase‐3, Beclin1 e LC3 foram examinadas por coloração Imunohistoquímica (IHQ). A expressão de Beclin1 e LC3 e a razão LC3‐II/LC3‐I foram detectadas por análise de western blot. Resultados Após a injeção intratecal de bupivacaína, ocorreu lesão patológica nos neurônios da medula espinhal e os níveis de apoptose e caspase‐3 aumentaram. A ativação da autofagia causada pela rapamicina mitigou de forma expressiva as alterações patológicas e diminuiu os níveis de apoptose e caspase‐3, aumentando a expressão de LC3 e Beclin1 e a razão LC3‐II/LC3‐I. Conclusões O aumento da autofagia diminui a apoptose dependente da caspase‐3 e melhora a sobrevivência neuronal in vivo. A ativação da autofagia pode ser uma estratégia terapêutica potencial para a neurotoxicidade induzida por anestésicos locais.

Abstract Background and objectives The mechanisms by which local anesthetics cause neurotoxicity are very complicated. Apoptosis and autophagy are highly coordinated mechanisms that maintain cellular homeostasis against stress. Studies have shown that autophagy activation serves as a protective mechanism in vitro. However, whether it also plays the same role in vivo is unclear. The aim of this study was to explore the role of autophagy in local anesthetic-induced neurotoxicity and to elucidate the mechanism of neurotoxicity in an intrathecally injected rat model. Methods Eighteen healthy adult male Sprague-Dawley rats were randomly divided into three groups. Before receiving an intrathecal injection of 1% bupivacaine, each rat received an intraperitoneal injection of vehicle or rapamycin (1 mg.kg-1) once a day for 3 days. The pathological changes were examined by Haematoxylin and Eosin (HE) staining. Apoptosis was analysed by TdT-mediated dUTP Nick-End Labelling (TUNEL) staining. Caspase-3, Beclin1 and LC3 expression was examined by Immunohistochemical (IHC) staining. Beclin1 and LC3 expression and the LC3-II/LC3-I ratio were detected by western blot analysis. Results After bupivacaine was injected intrathecally, pathological damage occurred in spinal cord neurons, and the levels of apoptosis and caspase-3 increased. Enhancement of autophagy with rapamycin markedly alleviated the pathological changes and decreased the levels of apoptosis and caspase-3 while increasing the expression of LC3 and Beclin1 and the ratio of LC3-II to LC3-I. Conclusions Enhancement of autophagy decreases caspase-3-dependent apoptosis and improves neuronal survivalin vivo. Activation of autophagy may be a potential therapeutic strategy for local anaesthetic-induced neurotoxicity.