Predictive modelling for postoperative acute kidney injury: big data enhancing quality or the Emperor's new clothes?

The increased availability of large clinical datasets together with increasingly sophisticated computing power has facilitated development of numerous risk prediction models for various adverse perioperative outcomes, including acute kidney injury (AKI). The rationale for developing such models is straightforward. However, despite numerous purported benefits, the uptake of preoperative prediction models into clinical practice has been limited. Barriers to implementation of predictive models, including limitations in their discrimination and accuracy, as well as their ability to meaningfully impact clinical practice and patient outcomes, are increasingly recognised. Some of the purported benefits of predictive modelling, particularly when applied to postoperative AKI, might not fare well under detailed scrutiny. Future research should address existing limitations and seek to demonstrate both benefit to patients and value to healthcare systems from implementation of these models in clinical practice.

Advanced chronic kidney disease after surgery and the contribution of acute kidney disease: a national observational cohort study.

BACKGROUND: Limited knowledge exists regarding long-term renal outcomes after noncardiac surgery. This study investigated the incidence of, and risk factors for, developing advanced chronic kidney disease (CKD) and major adverse kidney events within 1 yr of surgery in a nationwide cohort. METHODS: Adults without renal dysfunction before noncardiac surgery in Sweden were included between 2007 and 2013 in this observational multicentre cohort study. We analysed data from a national surgical database linked to several national and quality outcome registries. Associations of perioperative risk factors with advanced CKD (estimated glomerular filtration rate [eGFR] <30 ml min-1 1.73 m-2) and major adverse kidney events within 1 yr (MAKE365, comprising eGFR <30 ml min-1 1.73 m-2, chronic dialysis, death) were quantified. RESULTS: Of 237,124 patients, 1597 (0.67%) developed advanced CKD and 16,789 (7.1%) developed MAKE365. Risk factors for advanced CKD included higher ASA physical status, urological surgery, extended surgical duration, prolonged postoperative hospital stay, repeated surgery, and postoperative use of renin-angiotensin-aldosterone system blockers. Advanced acute kidney disease (AKD) (eGFR <30 ml min-1 1.73 m-2 within 90 postoperative days) occurred in 1661 (0.70%) patients and was associated with advanced CKD (subdistribution hazard ratio [SHR] 44.5, 95% confidence interval [CI] 38.7-51.1) and MAKE365 (hazard ratio [HR] 6.60, 95% CI 6.07-7.17). Among patients with advanced AKD after surgery 36% developed advanced CKD at 1 yr after surgery and 51% developed MAKE365. CONCLUSIONS: Advanced CKD within 1 yr after surgery is uncommon but clinically important in patients without preoperative renal dysfunction. Advanced AKD after surgery constitutes a major risk factor for advanced CKD and MAKE365.

Perioperative copeptin: predictive value and risk stratification in patients undergoing major noncardiac surgery-a prospective observational cohort study.

PURPOSE: Biomarkers can aid in perioperative risk stratification. While preoperative copeptin has been associated with adverse events, intraoperative information is lacking and this association may rather reflect a baseline risk. Knowledge about correlations between postoperative copeptin measurements and clinically relevant outcomes is scarce. We examined the association of perioperative copeptin concentrations with postoperative all-cause mortality and/or major adverse cardiac and cerebrovascular events (MACCE) at 12 months and 30 days as well as with perioperative myocardial injury (PMI). METHODS: We conducted a prospective observational cohort study of adults undergoing noncardiac surgery with intermediate to high surgical risk in Basel, Switzerland, and Düsseldorf, Germany from February 2016 to December 2020. We measured copeptin and cardiac troponin before surgery, immediately after surgery (0 hr) and once between the second and fourth postoperative day (POD 2-4). RESULTS: A primary outcome event of a composite of all-cause mortality and/or MACCE at 12 months occurred in 48/502 patients (9.6%). Elevated preoperative copeptin (> 14 pmol·L-1), immediate postoperative copeptin (> 90 pmol·L-1), and copeptin on POD 2-4 (> 14 pmol·L-1) were associated with lower one-year MACCE-free and/or mortality-free survival (hazard ratio [HR], 2.89; 95% confidence interval [CI], 1.62 to 5.2; HR, 2.07; 95% CI, 1.17 to 3.66; and HR, 2.47; 95% CI, 1.36 to 4.46, respectively). Multivariable analysis continued to show an association for preoperative and postoperative copeptin on POD 2-4. Furthermore, elevated copeptin on POD 2-4 showed an association with 30-day MACCE-free survival (HR, 2.15; 95% CI, 1.18 to 3.91). A total of 64 of 489 patients showed PMI (13.1%). Elevated preoperative copeptin was not associated with PMI, while immediate postoperative copeptin was modestly associated with PMI. CONCLUSION: The results of the present prospective observational cohort study suggest that perioperative copeptin concentrations can help identify patients at risk for all-cause mortality and/or MACCE. Other identified risk factors were revised cardiac risk index, body mass index, surgical risk, and preoperative hemoglobin. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02687776); first submitted 9 February 2016.

RéSUMé: OBJECTIF: Les biomarqueurs peuvent aider à la stratification du risque périopératoire. Bien que la copeptine préopératoire ait été associée à des événements indésirables, les informations peropératoires font défaut; plutôt, cette association pourrait refléter un risque de base. Les connaissances sur les corrélations entre les mesures postopératoires de la copeptine et les résultats cliniquement pertinents sont rares. Nous avons examiné l'association entre les concentrations de copeptine périopératoires et la mortalité postopératoire toutes causes confondues et/ou les événements indésirables cardiaques et cérébrovasculaires majeurs (EICCM/MACCE) à 12 mois et 30 jours ainsi qu'en cas de lésion myocardique périopératoire (LMP/PMI). MéTHODE: Nous avons réalisé une étude de cohorte observationnelle prospective d'adultes bénéficiant d'une chirurgie non cardiaque à risque chirurgical intermédiaire à élevé à Bâle, en Suisse, et à Düsseldorf, en Allemagne, de février 2016 à décembre 2020. Nous avons mesuré la copeptine et la troponine cardiaque avant la chirurgie, immédiatement après la chirurgie (0 h) et une fois entre le deuxième et le quatrième jour postopératoire (JPO 2-4). RéSULTATS: Un événement constituant un critère d'évaluation principal d'un composite de mortalité toutes causes confondues et/ou de MACCE à 12 mois est survenu chez 48/502 patient·es (9,6 %). Une élévation de la copeptine préopératoire (> 14 pmol·L−1), de la copeptine postopératoire immédiate (> 90 pmol·L−1) et de la copeptine aux JPO 2 à 4 (> 14 pmol·L−1) était associée à une survie sans MACCE et/ou sans mortalité à un an plus faible (rapport de risque [RR], 2,89; intervalle de confiance [IC] à 95 %, 1,62 à 5,2; RR, 2,07; IC 95 %, 1,17 à 3,66; et RR, 2,47; IC 95 %, 1,36 à 4,46, respectivement). L'analyse multivariée a aussi montré une association entre la copeptine préopératoire et postopératoire aux JPO 2 à 4. De plus, un taux élevé de copeptine aux JPO 2 à 4 a montré une association avec la survie sans MACCE à 30 jours (RR, 2,15; IC 95 %, 1,18 à 3,91). Au total, 64 des 489 patient·es présentaient une LMP (13,1 %). Un taux élevé de copeptine préopératoire n'a pas été associé à la LMP, tandis que la copeptine postopératoire immédiate était modestement associée à la LMP. CONCLUSION: Les résultats de la présente étude de cohorte observationnelle prospective suggèrent que les concentrations périopératoires de copeptine peuvent aider à identifier les personnes à risque de mortalité toutes causes confondues et/ou de MACCE. Les autres facteurs de risque identifiés étaient l'indice de risque cardiaque révisé, l'indice de masse corporelle, le risque chirurgical et l'hémoglobine préopératoire. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov (NCT02687776); première soumission le 9 février 2016.

Evaluating the Prevalence of Cardiac Surgery-associated Acute Kidney Injury After Septal Myectomy Combined With Concomitant Procedures in Obstructive Hypertrophic Cardiomyopathy.

OBJECTIVES: Hypertrophic obstructive cardiomyopathy (HOCM) may be treated by septal myectomy. Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common complication, but little is known about its incidence after septal myectomy. The objectives of this work were to evaluate the prevalence of CSA-AKI after septal myectomy and identify potential perioperative and phenotype-related factors contributing to CSA-AKI. DESIGN: This was a retrospective database analysis with new data analysis. SETTING: The study occurred in a single university academic expertise center for septal myectomy HOCM patients. PARTICIPANTS: Data from 238 HOCM patients with septal myectomy operated on between 2005 and 2022 were collected. INTERVENTIONS: CSA-AKI was stratified according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines using measurement of creatinine and urine production. Important HOCM phenotype-related and perioperative factors were analyzed for their possible associations with CSA-AKI. MEASUREMENTS AND MAIN RESULTS: CSA-AKI occurred in 45% of patients; of these, 55% were classified as KDIGO stage I and the remaining 45% as stage II, with no chronic kidney damage observed. Moreover, there were no phenotypical or perioperative characteristics that were more prevalent in the CSA-AKI cohort. However, the use of beta-blockers and coronary artery disease were more prevalent in the CSA-AKI cohort. CONCLUSIONS: CSA-AKI is a common complication after septal myectomy but was transient, and kidney function recovered in all patients.

Perception of Perioperative Risk for Arthroplasty Patients: A Poll of Chinese Orthopaedic Surgeons.

BACKGROUND: Informed by the precedent of an American Association of Hip and Knee Surgeons (AAHKS) survey, where 95% of participants reported instigating modifications to preoperative risk factors, this study appraised the approach of Chinese arthroplasty surgeons toward patients who had modifiable risks. METHODS: An adaptation of the AAHKS survey tool for a Chinese cohort was undertaken. The survey queried 600 Chinese Society of Hip and Knee Surgeons members on whether the perception of unoptimized medical comorbidities and socioeconomic elements affects the propensity to offer surgical procedures. RESULTS: Out of the distributed surveys, 150 responses were received, culminating in a response rate of 25%. The data illustrate that 98.7% of Chinese surgeons practice restrictions on arthroplasty access for patients who have modifiable risk factors, with notable frequencies for malnutrition (93.3%), anemia (91.3%), recent hyaluronic acid injections (within one month, 88.7%), and corticosteroid injections (within 3 months, 74.7%). Assessment criteria ahead of surgery included limitations such as a body mass index under 40 (47.3%), requirements for smoking cessation (57.3%), an acceptable hemoglobin A1c level (95.3%), and a dependent fasting blood glucose level (88%). Moreover, 87.3% of respondents endorsed the need for additional interventions for certain socioeconomically disadvantaged patients to achieve successful outcomes. A majority of respondents (94.7%) believed that more equitable access to care, facilitated by better-adjusted payment methodologies, could enhance patient outcomes. Current payment schemes were also perceived by a majority to potentially compromise outcomes for patients who have inadequate social support (80.7%), low socioeconomic status (67.3%), and those lacking insurance (72.7%). CONCLUSIONS: The consistency of the almost 99% response rate in addressing modifiable risk factors prior to arthroplasty aligns closely with the reported practices in the AAHKS survey. These findings underscore the shared valuation of preoperative risk factor optimization by Chinese and American arthroplasty surgeons, notwithstanding divergent healthcare system structures.

Preoperative Stress Testing before Non-Cardiac Surgery.

The current guidelines from various medical societies provide a good summary of data regarding various preoperative exercise tests in patients prior to non-cardiac surgical interventions. However, there is no consensus among experts on the appropriateness of these methods for identifying risk groups for potential perioperative complications. A large volume of published studies describes the role of preoperative exercise stress testing impact in improving the prediction of potential cardiovascular (CV) risk in patients after non-cardiac surgery. Numerous stress tests are available in clinical practice, and the methods used and the best choice depends on the purpose of the study and the availability of equipment in the hospital. Traditionally, the value of exercise electrocardiography (ECG), or ECG stress test, has been based on the belief that it is beneficial for perioperative cardiac risk prediction. However, in the past two decades, the key role of this method has lost its importance due to the growing trend toward the use of imaging techniques. Moreover, in light of current trends, the six-minute walk test (6MWT) is a helpful tool in preoperative assessment and plays an important role in postoperative rehabilitation. Interestingly, the recent finding showed how 6MWT affects the risk of postoperative complications. Cardiopulmonary testing, as a dynamic clinical tool, determines the cardiorespiratory status of a patient. Various clinical indications for cardiopulmonary exercise testing include evaluation of therapy, stratification of risk factors, diagnosis of disease, and control of physical activity. Stress testing is one of the most practical ways of predicting perioperative risk and managing patients. This test is based on ischemia provoked by pharmacological agents or exercise. There is no established evidence of a significant advantage of pharmacological stress over exercise stress imaging in subjects who are capable enough to be physically active. All of these studies examined a stress test for induced myocardial ischemia. Currently, there are no data on the use of ischaemic stress tests, especially diastolic stress tests, in the assessment of perioperative risk before non-cardiac surgical interventions. We consider it promising and essential to continue research in this direction in patients with coronary heart disease and other categories of cardiac patients, in particular, comorbid and low-symptomatic individuals, before elective high-risk surgical interventions.

Significance of Ultra-Radical Surgery in Extensive Metastatic Ovarian Growing Teratoma Syndrome.

INTRODUCTION: The aim of the study was to evaluate the perioperative risks and outcomes of ultra-radical surgery in patients with extensive metastatic ovarian growing teratoma syndrome (GTS). METHODS: We conducted a retrospective study of patients with extensive metastatic ovarian GTS treated in our hospital between 2000 and 2022. Patients' clinical characteristics, surgical treatment, and outcomes were evaluated. RESULTS: Overall, 13 patients were identified, and the median age at diagnosis of ovarian immature teratoma (IT) was 24 years (range: 5-37). The median interval between IT diagnosis and presenting GTS was 8 months (range: 2-60), with a median surgery delay of 5 months (range: 3-300). Peritoneum and liver were the most commonly affected sites (100%), followed by bowel (12 patients, 92.3%), diaphragm (12 patients, 92.3%), adnexa (9 patients, 69.2%), omentum (8 patients, 61.5%), uterus (7 patients, 53.8%), in the descending order. The mean operation time was 316 min (range: 180-625), and the mean blood loss volume was 992 mL (range: 200-5,000). Peritoneal metastasectomy (13 patients, 100%), diaphragmatic metastasectomy (12 patients, 92.3%), metastasis removal from the bowel (8 patients, 61.5%), partial hepatectomy (4 patients, 30.8%), bowel excision and anastomosis (1 patient, 7.7%) were also applied to achieve optimal debulking. R0 was achieved in 9 (69.2%) patients. A high rate of intraoperative blood transfusion (8 patients, 61.5%) and admission to the intensive care unit (9 patients, 69.2%) were observed, and the median postoperative hospitalization time was 8 days (range: 4-22). After a median follow-up of 3.3 years, 9 patients were free of disease, and 4 were alive with stable residual diseases. CONCLUSION: The survival outcomes in extensive metastatic ovarian GTS were satisfactory after ultra-radical surgery, while a proper therapeutic plan should be established due to the high perioperative risks.

Prediction of American Society of Anesthesiologists Physical Status Classification from preoperative clinical text narratives using natural language processing.

BACKGROUND: Electronic health records (EHR) contain large volumes of unstructured free-form text notes that richly describe a patient's health and medical comorbidities. It is unclear if perioperative risk stratification can be performed directly from these notes without manual data extraction. We conduct a feasibility study using natural language processing (NLP) to predict the American Society of Anesthesiologists Physical Status Classification (ASA-PS) as a surrogate measure for perioperative risk. We explore prediction performance using four different model types and compare the use of different note sections versus the whole note. We use Shapley values to explain model predictions and analyze disagreement between model and human anesthesiologist predictions. METHODS: Single-center retrospective cohort analysis of EHR notes from patients undergoing procedures with anesthesia care spanning all procedural specialties during a 5 year period who were not assigned ASA VI and also had a preoperative evaluation note filed within 90 days prior to the procedure. NLP models were trained for each combination of 4 models and 8 text snippets from notes. Model performance was compared using area under the receiver operating characteristic curve (AUROC) and area under the precision recall curve (AUPRC). Shapley values were used to explain model predictions. Error analysis and model explanation using Shapley values was conducted for the best performing model. RESULTS: Final dataset includes 38,566 patients undergoing 61,503 procedures with anesthesia care. Prevalence of ASA-PS was 8.81% for ASA I, 31.4% for ASA II, 43.25% for ASA III, and 16.54% for ASA IV-V. The best performing models were the BioClinicalBERT model on the truncated note task (macro-average AUROC 0.845) and the fastText model on the full note task (macro-average AUROC 0.865). Shapley values reveal human-interpretable model predictions. Error analysis reveals that some original ASA-PS assignments may be incorrect and the model is making a reasonable prediction in these cases. CONCLUSIONS: Text classification models can accurately predict a patient's illness severity using only free-form text descriptions of patients without any manual data extraction. They can be an additional patient safety tool in the perioperative setting and reduce manual chart review for medical billing. Shapley feature attributions produce explanations that logically support model predictions and are understandable to clinicians.

Development and validation of a multivariable prediction model in pediatric liver transplant patients for predicting intensive care unit length of stay.

BACKGROUND: Liver transplantation is the life-saving treatment for many end-stage pediatric liver diseases. The perioperative course, including surgical and anesthetic factors, have an important influence on the trajectory of this high-risk population. Given the complexity and variability of the immediate postoperative course, there would be utility in identifying risk factors that allow prediction of adverse outcomes and intensive care unit trajectories. AIMS: The aim of this study was to develop and validate a risk prediction model of prolonged intensive care unit length of stay in the pediatric liver transplant population. METHODS: This is a retrospective analysis of consecutive pediatric isolated liver transplant recipients at a single institution between April 1, 2013 and April 30, 2020. All patients under the age of 18 years receiving a liver transplant were included in the study (n = 186). The primary outcome was intensive care unit length of stay greater than 7 days. RESULTS: Recipient and donor characteristics were used to develop a multivariable logistic regression model. A total of 186 patients were included in the study. Using multivariable logistic regression, we found that age < 12 months (odds ratio 4.02, 95% confidence interval 1.20-13.51, p = .024), metabolic or cholestatic disease (odds ratio 2.66, 95% confidence interval 1.01-7.07, p = .049), 30-day pretransplant hospital admission (odds ratio 8.59, 95% confidence interval 2.27-32.54, p = .002), intraoperative red blood cells transfusion >40 mL/kg (odds ratio 3.32, 95% confidence interval 1.12-9.81, p = .030), posttransplant return to the operating room (odds ratio 11.45, 95% confidence interval 3.04-43.16, p = .004), and major postoperative respiratory event (odds ratio 32.14, 95% confidence interval 3.00-343.90, p < .001) were associated with prolonged intensive care unit length of stay. The model demonstrates a good discriminative ability with an area under the receiver operative curve of 0.888 (95% confidence interval, 0.824-0.951). CONCLUSIONS: We develop and validate a model to predict prolonged intensive care unit length of stay in pediatric liver transplant patients using risk factors from all phases of the perioperative period.

Two novel prehabilitation apps to help patients stop smoking and risky drinking prior to hip and knee arthroplasty.

PURPOSE: Daily smoking or risky drinking increases the risk of complications after surgery by ~50%. Intensive prehabilitation aimed at complete cessation reduces the complication rate but is time-consuming. The purpose of this study was to carry out preoperative pilot tests (randomized design) of the feasibility (1A) and validation (1B) of two novel prehabilitation apps, habeat® (Ha-app) or rehaviour® (Re-app). METHODS: Patients scheduled for hip or knee arthroplasty with daily smoking, risky drinking, or both were randomised to one of the two apps. In part 1A, eight patients and their staff measured feasibility on a visual analog scale (VAS) and were interviewed about what worked well and the challenges requiring improvement. In part 1B, seven patients and their staff tested the improved apps for up to two weeks before validating the understanding, usability, coverage, and empowerment on a VAS and being interviewed. RESULTS: In 1A, all patients and staff returned scores of ≥5 for understanding the apps and mostly suggested technical improvements. In 1B, the scores varied widely for both apps, with no consensus achieved. Two of four patients (Ha-app) and one-third of the patients (Re-app) found the apps helpful for reducing smoking, but without successful quitting. The staff experienced low app competencies among patients and high time consumption. Specifically, patients most often needed help for the Ha-app, and the staff most often for Re-app; however, the staff reported the Re-app dashboard was more user-friendly. Support and follow-up from an addiction specialist staff member were suggested to complement the apps, thereby increasing the time consumption for staff. CONCLUSIONS: This pilot study to test prototype apps generated helpful feedback for the app developers. Based on the patient and staff comments, multiple improvements in functionality seem required before scaling up the evaluation for effect on prehabilitation and postoperative complications.

Exploring the Utility of Brain Natriuretic Peptide Measurement in Vascular Surgery.

BACKGROUND: The Canadian Cardiovascular Society 2016 guidelines recommend pre-operative measurement of brain natriuretic peptide (BNP) to risk-stratify patients for a 30-day composite outcome of death, myocardial infarction, or asymptomatic myocardial injury after noncardiac surgery (MINS). Whether this practice affects outcomes is unclear. The aim of this study was to examine the clinical utility of brain natriuretic peptide and myocardial injury after noncardiac surgery. METHODS: Analysis of a prospectively maintained database identified all elective open vascular surgery cases at an academic teaching hospital from January 2015 to December 2018. Pre-operative BNP values were available from June 2018 onward after becoming institutionally mandated. Co-morbidities were also collected to stratify patients using the Revised Cardiac Risk Index. The composite outcome of 30-day mortality, myocardial infarction, or MINS was determined. RESULTS: Prior to BNP becoming an institutionally required test, data was available from 1176 open cases. The 30-day mortality was 1.3% (15/1176) and post-operative myocardial infarction rate was 2.3% (27/1176). BNP measurements were collected in 91 consecutive patients. Ten patients (11%) experienced the composite outcome of mortality, myocardial infarction, or MINS. Elevated BNP was associated with increased odds of the composite outcome (P = 0.04), but not with mortality or myocardial infarction. Revised Cardiac Risk Index score was not predictive of outcomes. The majority of patients who qualified for the composite outcome experienced only an asymptomatic troponin rise (80%). Two patients met the universal definition of myocardial infarction, one of whom died. No other deaths occurred within 30 days. Detection of MINS did not result in any significant changes to patient management. CONCLUSIONS: Elevated BNP correlates with increased MINS. An asymptomatic troponin rise is the most commonly observed event, with unclear clinical implications. BNP may over-estimate surgical risk. Further studies on the long-term outcomes of patients with elevated BNP and MINS are required before widely adopting this strategy in vascular surgery patients.

Perioperative risk of pancreatic head resection-nomogram-based prediction of severe postoperative complications as a decisional aid for clinical practice.

PURPOSE: To develop nomograms for pre- and early-postoperative risk assessment of patients undergoing pancreatic head resection. METHODS: Clinical data from 956 patients were collected in a prospectively maintained database. A test (n = 772) and a validation cohort (n = 184) were randomly generated. Uni- and multi-variate analysis and nomogram construction were performed to predict severe postoperative complications (Clavien-Dindo Grades III-V) in the test cohort. External validation was performed with the validation cohort. RESULTS: We identified ASA score, indication for surgery, body mass index (BMI), preoperative white blood cell (WBC) count, and preoperative alkaline phosphatase as preoperative factors associated with an increased perioperative risk for complications. Additionally to ASA score, BMI, indication for surgery, and the preoperative alkaline phosphatase, the following postoperative parameters were identified as risk factors in the early postoperative setting: the need for intraoperative blood transfusion, operation time, maximum WBC on postoperative day (POD) 1-3, and maximum serum amylase on POD 1-3. Two nomograms were developed on the basis of these risk factors and showed accurate risk estimation for severe postoperative complications (ROC-AUC-values for Grades III-V-preoperative nomogram: 0.673 (95%, CI: 0.626-0.721); postoperative nomogram: 0.734 (95%, CI: 0.691-0.778); each p ≤ 0.001). Validation yielded ROC-AUC-values for Grades III-V-preoperative nomogram of 0.676 (95%, CI: 0.586-0.766) and postoperative nomogram of 0.677 (95%, CI: 0.591-0.762); each p = 0.001. CONCLUSION: Easy-to-use nomograms for risk estimation in the pre- and early-postoperative setting were developed. Accurate risk estimation can support the decisional process, especially for IPMN-patients with an increased perioperative risk.

Perioperative Management of the Patient at High-Risk for Cardiac Surgery-Associated Acute Kidney Injury.

Acute kidney injury (AKI) is one of the most common major complications of cardiac surgery, and is associated with increased morbidity and mortality. Cardiac surgery-associated AKI has a complex, multifactorial etiology, including numerous factors such as primary cardiac dysfunction, hemodynamic derangements of cardiac surgery and cardiopulmonary bypass, and the possibility of a large volume of blood transfusion. There are no truly effective pharmacologic therapies for the management of AKI, and, therefore, anesthesiologists, intensivists, and cardiac surgeons must remain vigilant and attempt to minimize the risk of developing renal dysfunction. This narrative review describes the current state of the scientific literature concerning the specific aspects of cardiac surgery-associated AKI, and presents it in a chronological fashion to aid the perioperative clinician in their approach to this high-risk patient group. The evidence was considered for risk prediction models, preoperative optimization, and the intraoperative and postoperative management of cardiac surgery patients to improve renal outcomes.

Mortality in Adult Congenital Heart Disease: Analysis of Outcomes and Risk Stratification.

Adult congenital heart disease (ACHD) is a rising concern for the current healthcare system, with a prevalence that is anticipated to steadily increase through the year 2050. It is estimated that there are >1.4 million adults in the United States living with a congenital heart defect. Despite significant advances in medical and surgical therapy, most of these patients progress to advanced heart failure due to the unique anatomic, physiological, and hemodynamic abnormalities associated with the disease. Patient awareness of the disease coupled with advances in the diagnosis and treatment has led to a significant increase in the surgical treatment of CHD in adults. The authors aim to summarize and critically appraise the current literature on the morbidity, mortality, and risk scores associated with ACHD.

Central venous catheter-related thrombosis in pediatric surgical patients: A prospective observational study.

BACKGROUND: Perioperative central venous catheters are required but may be associated with various complications. AIMS: The purpose of our study was to assess the incidence and perioperative risk factors for catheter-related internal jugular vein thrombosis in pediatric surgical patients. METHODS: This prospective observational study included children under 6 years of age who were scheduled to undergo central venous catheterization of the right internal jugular vein under general anesthesia. A central venous catheter was inserted under real-time ultrasound guidance. An investigator examined for thrombosis using ultrasonography at predetermined time points. The primary aim was the incidence of catheter-related thrombosis from insertion until the 5th day postoperatively or the removal of the central venous catheter. The secondary aim was the determination of the risk factors for thrombosis. RESULTS: Eighty patients completed the study. Internal jugular vein thrombi were found in 31 patients (38.8%, 95% CI 28.0-49.4). On multiple logistic regression analyses, the number of insertion attempts was the only influencing factor for catheter-related thrombosis (p < .001). More than two insertion attempts increased the risk of thrombosis (odds ratio 5.6; 95% CI 1.7 - 18.7, p = .004). Anesthesia time (p = .017; mean difference 166.4 min; 95% CI 55.7-277.1), intraoperative red blood cell transfusion (p = .001; median difference 21.1 ml kg-1 ; 95% CI 6.6-34.4), and intensive care unit stay (p = .001; median difference 100.0 h; 95% CI 48-311) differed between patients with transient thrombosis and those with thrombosis lasting for more than 3 days. CONCLUSION: Internal jugular vein thrombosis was frequently detected by ultrasound following central venous catheterization in pediatric surgical patients. Multiple insertion attempts may be associated with the incidence of thrombosis. The clinical relevance of thrombi detected via ultrasound surveillance has not been determined.

Early mortality and neurologic outcomes following mitral valve surgery in the very elderly.

OBJECTIVES: Valve repair is the gold standard for treatment of degenerative mitral valve disease. As the population ages, patients undergoing valve degeneration and therefore considered for mitral valve surgery will naturally be getting older. We sought to evaluate whether mitral repair retained a survival advantage over replacement in patients ≥80 years old. METHODS: A retrospective cohort study was performed using data acquired from the United Kingdom National Adult Cardiac Surgery Audit for the outcomes of in-hospital mortality and postoperative cerebrovascular event (CVA). Individual multivariable logistic regression models were created to investigate adjusted associations between these outcomes and type of mitral valve operation, repair or replacement. Additionally, associations between the individual model parameters and in-hospital mortality and CVA were investigated. RESULTS: A total of 1140 patients underwent mitral repair (66.4%, median age 82.3), and 577 patients underwent mitral replacement (33.6%, median age 82.1). The overall age range was 80-92. The incidence of in-hospital mortality favored the repair group (4.4% vs. 8.3%, p = .001). Multivariable logistic regression modeling demonstrated an increased adjusted odds of in-hospital mortality for mitral valve replacement (MVR) (odd ratio [OR]: 2.01, 1.15-3.50, p = .01). The only other parameter associated with an increased adjusted odds of in-hospital mortality was postoperative dialysis (OR: 14.2, 7.67-26.5, p < .001). There was not a demonstrated association between MVR and perioperative CVA (OR: 1.11, 0.49-2.4, p = .8). CONCLUSIONS: In patients ≥80 years old, mitral valve repair (MVr) was shown to be associated with a decreased adjusted odds of mortality, with a null association with CVA. These results suggest that, if feasible, MVr should remain the preferred management strategy, even in the very elderly.

Machine learning to predict adverse outcomes after cardiac surgery: A systematic review and meta-analysis.

BACKGROUND: Machine learning (ML) models are promising tools for predicting adverse postoperative outcomes in cardiac surgery, yet have not translated to routine clinical use. We conducted a systematic review and meta-analysis to assess the predictive performance of ML approaches. METHODS: We conducted an electronic search to find studies assessing ML and traditional statistical models to predict postoperative outcomes. Our primary outcome was the concordance (C-) index of discriminative performance. Using a Bayesian meta-analytic approach we pooled the C-indices with the 95% credible interval (CrI) across multiple outcomes comparing ML methods to logistic regression (LR) and clinical scoring tools. Additionally, we performed critical difference and sensitivity analysis. RESULTS: We identified 2792 references from the search of which 51 met inclusion criteria. Two postoperative outcomes were amenable for meta-analysis: 30-day mortality and in-hospital mortality. For 30-day mortality, the pooled C-index and 95% CrI were 0.82 (0.79-0.85), 0.80 (0.77-0.84), 0.78 (0.74-0.82) for ML models, LR, and scoring tools respectively. For in-hospital mortality, the pooled C-index was 0.81 (0.78-0.84) and 0.79 (0.73-0.84) for ML models and LR, respectively. There were no statistically significant results indicating ML superiority over LR. CONCLUSION: In cardiac surgery patients, for the prediction of mortality, current ML methods do not have greater discriminative power over LR as measured by the C-index.

Perioperative risk factors for survival outcomes in elective colorectal cancer surgery: a retrospective cohort study.

BACKGROUND: Surgical resection remains the best option for long-term survival in colorectal cancer (CRC); however, surgery can lead to tumor cell release into the circulation. Previous studies have also shown that surgery can affect cancer cell growth. The role of perioperative factors influencing long-term survival in patients presenting for CRC surgery remains to be investigated. METHODS: This retrospective single-center cohort study was conducted to collect the clinical data of patients who underwent elective laparoscopic resection for CRC from January 2014 to December 2015, namely clinical manifestations, pathological results, and perioperative characteristics. Survival was estimated using the Kaplan-Meier log-rank test. Univariable and multivariable Cox regression models were used to compare hazard ratios (HR) for death. RESULTS: A total of 234 patients were eligible for analysis. In the multivariable Cox model, tumor-node-metastasis (TNM) stage (stage IV: HR 30.63, 95% confidence interval (CI): 3.85-243.65; P = 0.001), lymphovascular invasion (yes: HR 2.07, 95% CI 1.09-3.92; P = 0.027), inhalational anesthesia with isoflurane (HR 1.96, 95% CI 1.19-3.21; P = 0.008), and Klintrup-Makinen (KM) inflammatory cell infiltration grade (low-grade inflammation: HR 2.03, 95% CI 1.20-3.43; P = 0.008) were independent risk factors affecting 5-year overall survival after laparoscopic resection for CRC. CONCLUSIONS: TNM stage, lymphovascular invasion, isoflurane, and KM grade were independent risk factors affecting CRC prognosis. Sevoflurane and high-grade inflammation may be associated with improved survival in CRC patients undergoing resection.

The effect of cognitive dysfunction on mid- and long-term mortality after vascular surgery.

BACKGROUND: In recent decades, previous studies have noted the importance of frailty, which is a frequently used term in perioperative risk evaluations. Psychological and socioeconomical domains were investigated as part of frailty syndrome. The aim of this study was to assess the importance of these factors in mortality after vascular surgery. METHODS: In our prospective, observational study (ClinicalTrials.gov Identifier: NCT02224222), we examined 164 patients who underwent elective vascular surgery between 2014 and 2017. At the outpatient anaesthesiology clinic, patients completed a questionnaire about cognitive functions, depression and anxiety, social support and self-reported quality of life were assessed using a comprehensive frailty index, in addition to medical variables. Propensity score matching was performed to analyse the difference between patients and controls in a nationwide population cohort. The primary outcome was 4 year mortality. The Kaplan-Meier method and Cox regression analysis were used for statistical analyses. RESULTS: The patients' mean age was 67.05 years (SD: 9.49 years). Mini-Mental State Examination scores of less than 27 points were recorded for 41 patients. Overall mortality rates were 22.4 and 47.6% in the control and cognitive impairment groups, respectively (p = 0.013). In the univariate Cox regression analysis, cognitive impairment measured using age- and education-adjusted MMSE scores increased the risk of mortality (AHR: 2.842, 95% CI: 1.389-5.815, p = 0.004). CONCLUSION: Even mild cognitive dysfunction measured preoperatively using the MMSE represents a potentially important risk factor for mortality after vascular surgery.

Impaired vascular endothelial function as a perioperative risk predictor - a prospective observational trial.

BACKGROUND: In the recent years, an increasing number of patients with multiple comorbidities (e.g. coronary artery disease, diabetes, hypertension) presents to the operating room. The clinical risk factors are accompanied by underlying vascular-endothelial dysfunction, which impairs microcirculation and may predispose to end-organ dysfunction and impaired postoperative outcome. Whether preoperative endothelial dysfunction identifies patients at risk of postoperative complications remains unclear. In this prospective observational study, we tested the hypothesis that impaired flow-mediated dilation (FMD), a non-invasive surrogate marker of endothelial function, correlates with Days at Home within 30 days after surgery (DAH30). DAH30 is a patient-centric metric that captures postoperative complications and importantly also hospital re-admissions. METHODS: Seventy-one patients scheduled for major abdominal surgery were enrolled. FMD was performed pre-operatively prior to major abdominal surgery and patients were dichotomised at a threshold value of 10%. FMD was then correlated with DAH30 (primary endpoint) and postoperative complications (secondary endpoints). RESULTS: DAH30 did not differ between patients with reduced FMD and normal FMD (14 (4) (median (IQR)) vs. 15 (8), P = 0.8). Similary, no differences between both groups were found for CCI (normal FMD: 21 (30) (median (IQR)), reduced FMD: 26 (38), P = 0.4) or frequency of major complications (normal FMD: 7 (19%) (n (%)), reduced FMD: 12 (35%), P = 0.12). The regression analyses revealed that FMD in combination with ASA status and surgery duration had no additional significant predictive effect for DAH30, CCI or Clavien-Dindo score. CONCLUSION: FMD does not add predictive value with regards to DAH30, CCI or Clavien-Dindo score within our study cohort of patients undergoing abdominal surgery. TRIAL REGISTRATION: The study was registered in the German Clinical Trials Register ( DRKS00005472 ), prospectively registered on 25/11/2013.