Risk factors and in-hospital mortality of postoperative hyperlactatemia in patients after acute type A aortic dissection surgery

Abstract

Background Hyperlactatemia may be caused by increased production due to tissue hypoxia or non-hypoxia. The aim of this study was first to identify risk factors for postoperative hyperlactatemia (POHL) after Stanford type A acute aortic dissection surgery (AADS) and construct a predictive model, and second to evaluate the impact of POHL on prognosis. Methods This retrospective study involved patients undergoing AADS from January 2016 to December 2019 in Wuhan Union Hospital. Multivariate logistic regression analysis was performed to identify independent risk factors for POHL. A nomogram predicting POHL was established based on these factors and was validated in the original dataset. The receiver operating characteristic curve was drawn to assess the ability of postoperative lactate levels to predict the in-hospital mortality. Results A total of 188 patients developed POHL after AADS (38.6%). Male gender, surgery history, red blood cell transfusion and cardiopulmonary bypass time were identified as independent predictors. The C-index of the prediction model for POHL was 0.72, indicating reasonable discrimination. The model was well calibrated by visual inspection and goodness-of-fit test (Hosmer–Lemeshow χ2 = 10.25, P = 0.25). Decision and clinical impact curves of the model showed good clinical utility. The overall in-hospital mortality rate was 10.1%. Postoperative lactate levels showed a moderate predictive power for postoperative in-hospital mortality (C-index: 0.72). Conclusion We developed and validated a prediction model for POHL in patients undergoing AADS, which may have clinical utility in personal risk evaluation and preventive interventions. The POHL could be a good predictor for in-hospital mortality.

Lactate levels: A reliable tool to predict mortality in acute type A aortic dissections?

“…This correlation has been assessed by different studies, but variability remains regarding the timing of measurement of lactate in the postoperative period. Lactate levels were not a predictor of mortality when measured on admission to ICU but a positive correlation was observed when the measurement was carried out at 6 h and within 12 h of return to ICU 6 . Measuring the lactate level after a few hours in the ICU may be more logical and this is the area where the study by Gemelli et al 1 is especially valuable.…”

“…Apart from these three studies, where the correlation between lactate levels and the outcome was reported extensively, there are also other studies that used lactate levels as one of the parameters for determining outcome. These studies also had significant variations for defining “high lactate” and the values ranged from 3 to 6 mmol/L 4–6 …”

“…The other important issue with the correlation between lactate and outcome is the timing of measurement. Studies have tried to correlate lactate values at presentation 1,2,4,5 as well as after surgery in the intensive care unit (ICU) 1,3,6 . It has to be mentioned in this context that central aortic repair alone can lead to improvement in malperfusion in most cases.…”

“…These studies also had significant variations for defining "high lactate" and the values ranged from 3 to 6 mmol/L. [4][5][6] The important question, therefore, is what constitutes "high lactate". Normal lactate level ranges from 0.5 to 1.5 mmol/L and most studies in cardiac surgery have used the range between 2 and 5 mmol/L to define hyperlactatemia.…”

“…Studies have tried to correlate lactate values at presentation 1,2,4,5 as well as after surgery in the intensive care unit (ICU). 1,3,6 It has to be mentioned in this context that central aortic repair alone can lead to improvement in malperfusion in most cases. As a result, those patients where the lactate levels remain elevated despite successful operative repair are perhaps the ones likely to have a worse outcome.…”