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

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.

Base excess is superior to lactate-levels in prediction of ICU mortality after cardiac surgery.

INTRODUCTION: Cardiac surgery with the use of cardiopulmonary bypass is known to induce distinct metabolic changes. Respective changes in acid-base status including increased systemic lactate levels were previously related to clinical outcomes, but data remain controversial. Therefore, we aim to investigate the relevance of lactate and base excess (BE) levels on ICU-mortality in patients admitted to the ICU after cardiac surgery. MATERIALS AND METHODS: Perioperative data of patients treated in a tertiary care academic center admitted to the ICU after on-pump surgery were analyzed in a retrospective fashion. Receiver operation characteristic (ROC) curves were constructed for admission lactate-levels and BE with calculation of optimal cut-off values to predict ICU mortality. Univariate followed by multivariate regression models were constructed to identify potential outcome-relevant indices. RESULTS: Data from 1,058 patients were included in the analysis. Area under the curves for prediction of ICU mortality were 0.79 for lactate levels at ICU admission (sensitivity 61.9%/ specificity 87.5%; optimal cut-off level 3.9mmol/l), and 0.7 for BE (sensitivity 52.4%/ specificity 93.8%, optimal cut-off level -6.7), respectively. Multivariate regression identified BE < -6.7 as the single metabolic predictor of ICU-mortality (HR 4.78, 95%-CI 1.4-16.33, p = 0.01). Explorative subgroup analyses revealed that the combination of lactate ≤3.9mmol/l and BE ≤ -6.7 has stronger impact on mortality than a combination of lactate of >3.9mmol/l and BE > -6.7 (HR 2.56, 95%-CI 0.18-37.17). CONCLUSIONS: At ICU-admission, severely reduced BE appears superior to hyperlactatemia with regard to prediction of ICU-mortality in patients after cardiac surgery.

Prognostic Value of Hyperlactatemia and Lactate Clearance After Mitral Valve Surgery.

OBJECTIVES: Blood lactate is frequently used to guide management in critically ill patients. In patients undergoing mitral valve surgery, an elevated lactate level is frequently observed; however, overall mortality is low. The authors hypothesized that hyperlactemia is not a useful predictor of poor outcomes in this patient population. The main aim of this study was to explore how blood lactate level and lactate clearance are associated with 30-day mortality and major adverse events in patients undergoing mitral valve surgery. DESIGN: This was a retrospective database review. Logistic regression analysis was performed to assess the associations of perioperative factors with blood lactate in the intensive care unit (ICU). SETTING: Tertiary-care teaching hospital. PARTICIPANTS: The study comprised 917 patients undergoing mitral valve surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The majority of patients (71.8%) had elevated blood lactate ≥2 mmol/L on ICU admission; however, within 24 hours, 85.1% of all patients had normal lactate values. Overall 30-day mortality was 2.29% (n = 21). The combination of lactate ≥7 mmol/L on ICU admission and a persistent elevated blood lactate level 24 hours after ICU admission provides an excellent prediction of 30-day mortality (C statistic = 0.85). However, even a significantly elevated lactate level on ICU admission was well-tolerated in the majority of patients as long as lactate values normalized within 24 hours. Male sex, longer cardiopulmonary bypass time, blood transfusion in the ICU, and an elevated blood lactate level on ICU admission and 12 hours after ICU admission all were independent risk factors of clearance failure. CONCLUSIONS: An elevated blood lactate level is common after mitral valve surgery and is well-tolerated in the majority of patients. Adding lactate clearance improved the predictive value of the blood lactate level.

Hyperlactatemia in ICU patients: Incidence, causes and associated mortality.

PURPOSE: To describe the incidence, causes and associated mortality of hyperlactatemia in critically ill patients and to evaluate the association between lactate clearance and in-hospital survival. METHODS: Retrospective cohort study of patients with hyperlactatemia admitted to the ICU. Hyperlactatemia was defined as a blood lactate concentration ≥5mmol/L and high-grade hyperlactatemia a lactate level ≥10mmol/L. Lactate clearance was calculated as the percentage of decrease in lactate concentration from the peak value. RESULTS: Of 10,123 patients, 1373 (13.6%) had lactate concentration ≥5mmol/L, and 434(31.6%) of them had ≥10mmol/L. The most common causes of hyperlactatemia were sepsis/septic shock and post-cardiac surgery. An association was found between lactate concentration and in-hospital mortality (p<0.001). The area under the receiver-operating-characteristics (ROC) of lactate concentration and the optimal cut off to predict mortality were 0.72 (0.70-0.75) and 8.6mmol/L, respectively. ROC analysis for lactate clearance to predict in-hospital survival showed that the best area under the curve was obtained at 12h: 0.67 (95% confidence interval 0.59-0.75). CONCLUSIONS: Hyperlactatemia was common and associated with a high mortality in critically ill patients. Lactate clearance had limited utility for predicting in-hospital survival.

Use of Postoperative Peak Arterial Lactate Level to Predict Outcome After Cardiac Surgery.

OBJECTIVES: In the present study, the authors investigated the predictive value of postoperative peak arterial lactate levels for early and late mortality after cardiac surgery. DESIGN: Retrospective analysis of prospectively collected data. SETTING: Single-center study in an academic hospital. PARTICIPANTS: Adult patients who underwent cardiac surgery between 2004 and 2014 (n = 16,376). INTERVENTIONS: Different cardiac surgical procedures. MEASUREMENTS AND RESULTS: Patients were classified according to the peak arterial lactate level (PALL) within 3 days postoperatively. Logistic regression analysis and Cox regression analysis were performed to identify postoperative peak arterial lactate level as a predictor for early and late mortality respectively. In 8460 patients (51.7%), lactate was not measured postoperatively because these patients were managed according to the fast-track protocol. These patients constituted group 1 in our population but were excluded from the regression analysis. The remaining patients (n = 7,916; 48.3%) were divided according to the postoperative peak arterial lactate level (PALL): PALL<5 mmol/L (group 2), PALL 5 to 10 mmol/L (group 3), and PALL of>10 mmol/L (group 4). Early mortality was 3.7%, 20.4%, and 62.9% in groups 2, 3, and 4 respectively (p<0.0001). This mortality rate was significantly higher than that of group 1 (1.6%); p<0.0001. Multivariate regression analyses revealed postoperative peak arterial lactate as a significant predictor of 30-day mortality (odds ratio = 1.44 [1.39-1.48], p<0.001) as well as for late mortality (hazard ratio = 1.05 [1.01-1.10], p<0.025). CONCLUSIONS: Postoperative peak arterial lactate level in patients undergoing cardiac surgery is an independent predictor for both early and late mortality.

Relationship Between Peak Lactate and Patient Outcome Following High-Risk Gastrointestinal Surgery: Influence of the Nature of Their Surgery: Elective Versus Emergency.

OBJECTIVES: The association between hyperlactatemia and adverse outcome in patients admitted to ICUs following gastrointestinal surgery has not been reported. To explore the hypothesis that in a large cohort of gastrointestinal surgical patients, the peak serum lactate (in the first 24 hr) observed in patients admitted to ICU following surgery is associated with unadjusted and severity-adjusted acute hospital mortality and that the strength of association is greater in patients admitted following "emergency" surgery than in patients admitted following "elective" surgery. DESIGN: A retrospective cohort study of all patients who had gastrointestinal surgery and were admitted directly to the ICU between 2008 and 2012. SETTING: Two hundred forty-nine hospitals in the United Kingdom. PATIENTS: One hundred twenty-one thousand nine hundred ninety patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Peak blood lactate in the first 24 hours of admission to critical care, acute hospital mortality, length of stay, and other variables routinely collected within the U.K. Intensive Care National Audit and Research Centre Case Mix Programme database. Elevated blood lactate was associated with increased risk of death and prolonged duration of stay, and the relationship was maintained once adjusted for confounding variables. The positive association between mortality and levels of blood lactate continued down into the "normal range," without evidence of a plateau. There was no difference in the extent to which hyperlactatemia was related to mortality between patients admitted following elective and emergency surgery. CONCLUSIONS: These findings have implications for our understanding of the role of lactate in critically ill patients.

Frequency and outcomes of severe hyperlactatemia after elective cardiac surgery.

BACKGROUND: Hyperlactatemia is relatively common in the cardiac surgical patient and is usually considered a marker of illness severity. The frequency and impact of severe hyperlactatemia after elective cardiac surgery has not been described, and prognosis may be different compared with that for other surgical or medical critically ill patient populations. METHODS: We conducted a retrospective study to evaluate the hospital course and outcomes of patients who developed severe postoperative hyperlactatemia (SPHL; lactate >10 mmol/L) after elective cardiac surgery, from January 1, 2008 to December 31, 2012, at a large, academic, tertiary referral center. RESULTS: Of 9580 cardiac surgical patients who met inclusion criteria, 121 (1.26%) developed SPHL. The most common cause was cardiogenic shock (53.8%). In-hospital mortality was 40.5% but varied widely based on the cause of the SPHL. All patients with definite mesenteric ischemia (n = 5) or extremity compartment syndrome (n = 6) at the time of SPHL died in the hospital. Forty patients (33.1%) were discharged to home, whereas 32 (26.4%) were discharge to a skilled-care facility. CONCLUSIONS: Severe postoperative hyperlactatemia is rare after elective cardiac surgery. Although this phenomenon continues to be associated with mortality, >50% of patients survived to hospital discharge, a more favorable prognosis, compared with other patient populations based on lactate levels alone. Important exceptions were patients who had extremity compartment syndrome or mesenteric ischemia, which were associated with in-hospital death in all cases. In all other etiologic groups, a substantial proportion of patients were discharged to home.

Extreme Hyperlactatemia After Heart Transplantation: One Center's Experience.

INTRODUCTION: Hyperlactatemia may occur early after cardiac surgery and is correlated with prognosis. This study was conducted to analyze the perioperative variables and postoperative outcomes among heart transplant recipients with extremely high lactate levels (>15 mmol/L). METHODS: The single-center medical records of heart transplantation from June 2006 to May 2013 were retrospectively reviewed for patient characteristics, perioperative hemodynamic variables, arterial blood gas analysis data, and postoperative mortality. RESULTS: Among 58 consecutive heart transplant recipients, lactate levels over the detectable upper limit (>15 mmol/L) were identified in 12 patients after intensive care unit admission, with peak time at 1.9 ± 2.0 (range 0-6.1) hours. The maximal preoperative lactate level was 3.1 mmol/L, and most (11/12) postoperative lactate levels returned to <4 mmol/L at 27.5 ± 12.8 hours after surgery (range 15-58, median 24), displaying a trend toward delayed extubation time in 10 recipients (P < .01). Blood glucose levels elevated significantly from preoperative 148.9 ± 45.2 to 375.7 ± 96.9 mg/dL at peak lactate level (P < .01). Four patients died in the ICU (range 5-32 days), 4 died after discharge (range 5-57 months), with 6 in total surviving over 1 year. CONCLUSION: Extreme hyperlactatemia commonly occurred early after heart transplantation and mostly recovered within 30 hours; however, with delayed extubation time after operation.