Impact of hypothermia level on neurological and renal outcomes in emergency aortic surgery: a single-centre experience.

BackgroundTemperature management during emergency surgery for acute aortic syndrome is critical for neurological, renal, and systemic protection. Recent European Association for Cardio-Thoracic Surgery (EACTS) guidelines recommend moderate hypothermia with antegrade cerebral perfusion for hemiarch procedures. Nevertheless, deep hypothermic circulatory arrest (DHCA) remains common. This study evaluates neurological and other postoperative outcomes across different intraoperative temperature ranges.MethodsA single-centre retrospective study of consecutive patients undergoing surgery for acute aortic syndrome between 2018-2023. Demographic, intraoperative, and postoperative data on mortality, hospitalization, neurological, renal outcomes, and blood product usage were collected. Patients were stratified by intraoperative temperature: deep (≤20°C), low-moderate (20.1-24°C), high-moderate (24.1-28°C), and mild (>28°C) hypothermia. Logistic regression identified predictors of binary adverse outcomes. A sensitivity analysis was conducted using 24.0°C as the threshold in hemiarch surgery patients.ResultsA total of 175 patients (median age 64 years; 37% female) were included; of whom 89% underwent hemiarch replacement. Cardiopulmonary bypass duration decreased progressively with warmer intraoperative temperatures, ranging from 270.5 minutes in deep hypothermia to 164 minutes in mild hypothermia. The 30-day mortality was 18.9% (n = 33/175), and the overall stroke rate was 19.4% (n = 34/175). Among patients undergoing hemiarch repair, warmer temperatures were associated with lower stroke incidence (mild hypothermia 11%) compared with high-moderate (8.8%), low-moderate (26%), and deep hypothermia (27%) (p = 0.049), and with shorter intensive care admission (p = 0.036). However, multivariate regression showed that the four-category comparison did not reach significance for the assessed outcomes once adjusted for confounding variables. A sensitivity analysis at 24.0°C showed an independent association with reduced stroke risk (OR 0.23, 95% CI 0.08-0.64, p = 0.005).DiscussionOur findings support current EACTS recommendations favouring moderate-to-mild hypothermia for hemiarch replacement, with potential protective effects. Further studies should determine the optimal temperature strategy for patients undergoing total arch replacement.