| Objective: Hyperlactatemia is common in cardiac surgery and is associated with increased rates of major postoperative complications,prolonged hospital stay,and increased mortality.However,description of risk factors for postoperative hyperlactatemia,its impact on postoperative outcomes,and assessment of its prognostic value in the patient population undergoing Stanford type A aortic dissection surgery are limited.Methods: The clinical medical records of adult patients who underwent acute Stanford type A aortic dissection surgery in Wuhan Union Hospital from January 2016 to December 2019 were retrospectively collected.Univariable analysis and multivariable logistic regression analysis were used to identify independent risk factors for postoperative hyperlactatemia.Based on a multivariable regression model,a risk prediction model for postoperative hyperlactatemia was constructed.Receiver operating characteristic(ROC)curve was drawn to assess the discrimination power of the prediction model.The calibration curve was used to evaluate the calibration ability of the model.Decision curve analysis was used to assess the clinical utility of the model.Long-term follow-up of patients discharged from the hospital after Stanford type A aortic dissection surgery was conducted through outpatient and/or telephone contact.ROC curves were drawn to evaluate the predictive effect of peak lactate levels and hyperlactatemia on postoperative complications and mortality.Propensity score matching(PSM)analysis was used to reduce the effect of bias and confounding variables to analyze the association between early postoperative hyperlactatemia and postoperative complications and mortality.Time-to-event variables were estimated using the Kaplan-Meier method,and differences between groups were compared using the logrank test.Results: The incidence of postoperative hyperlactatemia(>4 mmol/L)was 38.6%(188/487).Male gender,surgical history,increased intraoperative red blood cell transfusion,and prolonged cardiopulmonary bypass time were identified as independent risk factors for postoperative hyperlactatemia.The area under curve(AUC)of the prediction model was0.72,indicating moderate discrimination power.The model had good calibration ability(Hosmer-Lemeshow χ2=10.25,P=0.25).Decision curves and clinical impact curves also showed that the model had good clinical utility.Compared with patients without hyperlactatemia,patients with hyperlactatemia had higher rates of postoperative acidosis,tachycardia,tracheostomy,continuous renal replacement therapy and death,and experienced longer ICU stay(P<0.05).Overall in-hospital mortality was 10.1%.Peak postoperative lactate had moderate predictive power for in-hospital mortality(AUC,0.72;best cut-off value,3.75 mmol/L;sensitivity,0.755;specificity,0.616),and still had reasonable predictive power(AUC,0.69;best cut-off value,8.45 mmol/L;sensitivity,0.457;specificity,0.914)after PSM.The Kaplan-Meier curve showed that there was no significant difference in long-term all-cause mortality,dissection-related mortality,and stroke events between the non-hyperlactatemia/hyperlactatemia groups(Log-rank P>0.05).Conclusions: Postoperative hyperlactatemia was prevalent in the patient population undergoing acute Stanford type A aortic dissection surgery.This study is the first to construct a risk prediction model for postoperative hyperlactatemia in patients who underwent Stanford type A aortic dissection surgery and present it in the form of a nomogram for clinical application.Prediction model had good discrimination power,calibration ability,and clinical utility,and may be useful for personal risk assessment of patients as well as clinical decision-making.Peak postoperative lactate was a good predictor of postoperative in-hospital mortality after acute Stanford type A aortic dissection surgery.Postoperative hyperlactatemia was associated with poor short-term postoperative outcomes,but it was not a useful predictor of long-term outcomes after Stanford type A aortic dissection surgery. |
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