Severity and Duration of Acute Kidney Injury and Chronic Kidney Disease after Cardiac Surgery

Early Acute Kidney Injury Recovery in Elderly Patients Undergoing Valve Replacement Surgery

OBJECTIVES

This study was designed to determine the incidence, contributing factors, and prognostic implications of acute kidney injury (AKI) recovery patterns in patients who experienced AKI after valve replacement surgery (VRS).

DESIGN

A retrospective cohort study was conducted.

SETTING

The work took place in a postoperative care center in a single large-volume cardiovascular center.

PARTICIPANTS

Patients undergoing VRS between January 2010 and December 2019 were enrolled.

INTERVENTION

Patients were categorized into three groups based on their postoperative AKI status: non-AKI, AKI with early recovery (less than 48 hours), and persistent AKI.

MEASUREMENT AND MAIN RESULTS

The primary outcome was in-hospital major adverse clinical events. The secondary outcomes included in-hospital and 1-year mortality. A total of 4,161 patients who developed AKI following VRS were included. Of these, 1,513 (36.4%) did not develop postoperative AKI, 1,875 (45.1%) experienced AKI with early recovery, and 773 (18.6%) had persistent AKI. Advanced age, diabetes, New York Heart Association III-IV heart failure, moderate-to-severe renal dysfunction, anemia, and AKI stages 2 and 3 were identified as independent risk factors for persistent AKI. In-hospital major adverse clinical events occurred in 59 (3.9%) patients without AKI, 88 (4.7%) with early AKI recovery, and 159 (20.6%) with persistent AKI (p < 0.001). Persistent AKI was independently associated with an increased risk of in-hospital adverse events and 1-year mortality. In contrast, AKI with early recovery did not pose additional risk compared with non-AKI patients.

CONCLUSIONS

In patients who develop AKI following VRS, early AKI recovery does not pose additional risk compared with non-AKI. However, AKI lasting more than 48 hours is associated with an increased risk of in-hospital and long-term adverse outcomes.

A Mild Increase in Serum Creatinine after Surgery Is Associated with Increased Mortality

Background: Acute kidney injury (AKI), a prevalent postoperative complication, predominantly manifests as stage 1, characterized by a mild elevation in serum creatinine (SCr). There is yet to be a consensus regarding the association between stage 1 AKI and adverse outcomes in surgical patients. Methods: This retrospective study enrolled adult patients who underwent at least one surgery during hospitalization from the MIMIC IV database. AKI was diagnosed when the KDIGO creatinine criteria were satisfied within 7 days after surgery. Stage 1a AKI was defined as an absolute increase in SCr of 26.5 μmol/L, and stage 1b was defined as a 50% relative increase. Stage 1 AKI was also divided into transient and persistent substages based on whether the AKI recovered within 48 h after onset. The association between stage 1 AKI and its substages and in-hospital mortality was evaluated. Results: Among 49,928 patients enrolled, 9755 (19.5%) developed AKI within 7 days after surgery, of which 7659 (78.5%) presented with stage 1 AKI. The median follow-up was 369 (367, 372) days. Stage 1 AKI was significantly associated with in-hospital mortality after adjustment (aHR, 2.73; 95% CI, 2.29, 3.26). Subgroup analyses showed that the risk of stage 1 AKI on in-hospital mortality was attenuated by age ≥ 65 years (p for interaction = 0.017) or a baseline eGFR < 60 mL/min per 1.73 m2 (p for interaction = 0.001). Compared with non-AKI, patients with stage 1b (aHR, 3.06; 95% CI, 2.56, 3.66) and persistent stage 1 (aHR, 2.03; 95% CI, 1.61, 2.57) AKI had an increased risk of in-hospital mortality; however, this risk was not significant in those with stage 1a (aHR, 1.01; 95% CI, 0.68, 1.51) and transient stage 1 (aHR, 1.11; 95% CI, 0.79, 1.57) AKI. Conclusions: Stage 1 AKI exhibits an independent correlation with a heightened mortality risk among surgical patients. Consequently, a tailored adaptation of the KDIGO AKI classification may be necessitated for the surgical population, particularly those presenting with decreased baseline kidney function.

A Signature of Pre-Operative Biomarkers of Cellular Senescence to Predict Risk of Cardiac and Kidney Adverse Events after Cardiac Surgery

Importance

Improved pre-operative risk stratification methods are needed for targeted risk mitigation and optimization of care pathways for cardiac patients. This is the first report demonstrating pre-operative, aging-related biomarkers of cellular senescence and immune system function can predict risk of common and serious cardiac surgery-related adverse events.

Design

Multi-center 331-patient cohort study that enrolled patients undergoing coronary artery bypass grafing (CABG) surgery with 30-day follow-up. Included a quaternary care center and two community-based hospitals. Primary outcome was KDIGO-defined acute kidney injury (AKI). Secondary outcomes: decline in eGFR ≥25% at 30d and a composite of major adverse cardiac and kidney events at 30d (MACKE30). Biomarkers were assessed in blood samples collected prior to surgery.

Results

A multivariate regression model of six senescence biomarkers (p16, p14, LAG3, CD244, CD28 and suPAR) identified patients at risk for AKI (NPV 86.6%, accuracy 78.6%), decline in eGFR (NPV 93.5%, accuracy 85.2%), and MACKE30 (NPV 91.4%, accuracy 79.9%). Patients in the top risk tertile had 7.8 (3.3-18.4) higher odds of developing AKI, 4.5 (1.6-12.6) higher odds of developing renal decline at 30d follow-up, and 5.7 (2.1-15.6) higher odds of developing MACKE30 versus patients in the bottom tertile. All models remained significant when adjusted for clinical variables.

Conclusions

A network of senescence biomarkers, a fundamental mechanism of aging, can identify patients at risk for adverse kidney and cardiac events when measured pre-operatively. These findings lay the foundation to improve pre-surgical risk assessment with measures that capture heterogeneity of aging, thereby improving clinical outcomes and resource utilization in cardiac surgery.

Predicting pediatric cardiac surgery-associated acute kidney injury using machine learning

BACKGROUND

Prediction of cardiac surgery-associated acute kidney injury (CS-AKI) in pediatric patients is crucial to improve outcomes and guide clinical decision-making. This study aimed to develop a supervised machine learning (ML) model for predicting moderate to severe CS-AKI at postoperative day 2 (POD2).

METHODS

This retrospective cohort study analyzed data from 402 pediatric patients who underwent cardiac surgery at a university-affiliated children's hospital, who were separated into an 80%-20% train-test split. The ML model utilized demographic, preoperative, intraoperative, and POD0 clinical and laboratory data to predict moderate to severe AKI categorized by Kidney Disease: Improving Global Outcomes (KDIGO) stage 2 or 3 at POD2. Input feature importance was assessed by SHapley Additive exPlanations (SHAP) values. Model performance was evaluated using accuracy, area under the receiver operating curve (AUROC), precision, recall, area under the precision-recall curve (AUPRC), F1-score, and Brier score.

RESULTS

Overall, 13.7% of children in the test set experienced moderate to severe AKI. The ML model achieved promising performance, with accuracy of 0.91 (95% CI: 0.82-1.00), AUROC of 0.88 (95% CI: 0.72-1.00), precision of 0.92 (95% CI: 0.70-1.00), recall of 0.63 (95% CI: 0.32-0.96), AUPRC of 0.81 (95% CI: 0.61-1.00), F1-score of 0.73 (95% CI: 0.46-0.99), and Brier score loss of 0.09 (95% CI: 0.00-0.17). The top ten most important features assessed by SHAP analyses in this model were preoperative serum creatinine, surgery duration, POD0 serum pH, POD0 lactate, cardiopulmonary bypass duration, POD0 vasoactive inotropic score, sex, POD0 hematocrit, preoperative weight, and POD0 serum creatinine.

CONCLUSIONS

A supervised ML model utilizing demographic, preoperative, intraoperative, and immediate postoperative clinical and laboratory data showed promising performance in predicting moderate to severe CS-AKI at POD2 in pediatric patients.

Adverse renal effects associated with cardiopulmonary bypass

Cardiac surgery on cardiopulmonary bypass (CPB) is associated with postoperative renal dysfunction, one of the most common complications of this surgical cohort. Acute kidney injury (AKI) is associated with increased short-term morbidity and mortality and has been the focus of much research. There is increasing recognition of the role of AKI as the key pathophysiological state leading to the disease entities acute and chronic kidney disease (AKD and CKD). In this narrative review, we will consider the epidemiology of renal dysfunction after cardiac surgery on CPB and the clinical manifestations across the spectrum of disease. We will discuss the transition between different states of injury and dysfunction, and, importantly, the relevance to clinicians. The specific facets of kidney injury on extracorporeal circulation will be described and the current evidence evaluated for the use of perfusion-based techniques to reduce the incidence and mitigate the complications of renal dysfunction after cardiac surgery.

A pilot study to explore patterns and predictors of delayed kidney decline after cardiopulmonary bypass

There is no current consensus on the follow up of kidney function in patients undergoing cardiopulmonary bypass (CPB). The main objectives of this pilot study is to collect preliminary data on kidney function decline encountered on the first postoperative visit of patients who have had CPB and to identify predictors of kidney function decline post hospital discharge. Design: Retrospective chart review. Adult patients undergoing open heart procedures utilizing CPB. Patient demographics, type of procedure, pre-, intra-, and postoperative clinical, hemodynamic echocardiographic, and laboratory data were abstracted from electronic medical records. Acute kidney disease (AKD), and chronic kidney disease (CKD) were diagnosed based on standardized criteria. Interval change in medications, hospital admissions, and exposure to contrast, from hospital discharge till first postoperative visit were collected. AKD, and CKD as defined by standardized criteria on first postoperative visit. 83 patients were available for analysis. AKD occurred in 27 (54%) of 50 patients and CKD developed in 12 (42%) out of 28 patients. Older age was associated with the development of both AKD and CKD. Reduction in right ventricular cardiac output at baseline was associated with AKD (OR: 0.5, 95% CI: 0.3, 0.79, P = 0.01). Prolongation of transmitral early diastolic filling wave deceleration time was associated with CKD (OR: 1.02, 95% CI: 1.01, 1.05, P = 0.03). In-hospital acute kidney injury (AKI) was a predictor of neither AKD nor CKD. AKD and CKD occur after CPB and may not be predicted by in-hospital AKI. Older age, right ventricular dysfunction and diastolic dysfunction are important disease predictors. An adequately powered longitudinal study is underway to study more sensitive predictors of delayed forms of kidney decline after CPB.

Impact of Postarrest Vasoactive-Inotropic Score on Acute Kidney Injury in Cardiac Arrest Survivors: A Retrospective Cohort Study

Background

Postarrest acute kidney injury (AKI) is a major health burden because it is associated with prolonged hospitalization, increased dialysis requirement, high mortality, and unfavorable neurological outcomes. Managing hemodynamic instability during the early postarrest period is critical; however, the role of quantified vasopressor dependence in AKI development in relation to illness severity remains unclear.

Methods

A retrospective, observational cohort study that enrolled 411 non-traumatic adult cardiac arrest survivors without pre-arrest end-stage kidney disease between January 2017 and December 2019, grouped according to their baseline kidney function. The criteria for kidney injury were based on the Kidney Disease: Improving Global Outcomes definition and AKI staging system. The degree of vasopressor dependence within the first 24 h following return of spontaneous circulation (ROSC) was presented using the maximum vasoactive-inotropic score ( VIS max ).

Results

Of the 411 patients, 181 (44%) had early AKI after ROSC. Patients with AKI showed an increased risk of in-hospital mortality (adjusted OR [aOR] 5.40, 95% CI 3.36-8.69, p < 0.001) and unfavorable neurological outcome (aOR 5.70, 95% CI 3.45-9.43, p < 0.001) compared to patients without AKI. The risk of adverse outcomes increased with illness severity. Patients with vasopressor support had an increased risk of early AKI. A low VIS max was associated with AKI stage 1-2 (aOR 2.51, 95% CI 1.20-5.24), whereas a high VIS max was associated with an increased risk for AKI stage 3 (aOR 2.46, 95% CI 1.28-4.75).

Conclusions

Early AKI is associated with an increased risk of in-hospital mortality and unfavorable neurologic recovery in cardiac arrest survivors. Postarrest VIS max is an independent predictor of the development and severity of AKI following ROSC, regardless of baseline kidney function.

Incidence of Post-laparotomy Acute Kidney Injury Among Abdominal Trauma Patients and Its Associated Risk Factors at King Abdulaziz Medical City, Riyadh

Background This research study investigates the prevalence of acute kidney injury (AKI) in trauma patients undergoing emergency laparotomies. AKI is a common complication in major surgeries and is associated with various adverse effects. The study aims to explore the relationship between AKI and other comorbidities in this specific context. Methodology This is a retrospective cohort study. All patients who had laparotomy after abdominal trauma at King Abdulaziz Medical City (KAMC) and met the inclusion criteria were included in the study. Nonprobability consecutive sampling was used. Data were collected by chart review using the Best-Care system at KAMC. Descriptive statistics were used to summarize and describe the characteristics of the study participants. Frequencies and percentages were calculated for categorical variables, such as comorbidities. For continuous variables, mean and standard deviations were calculated and tabulated. All statistical calculations were performed using IBM SPSS Statistics for Windows, Version 27.0 (IBM Corp., Armonk, NY, USA). Results This research study included 152 patients who underwent laparotomy, and the majority of patients (146, 96%) did not experience AKI. Several comorbidities were observed, with hypertension and diabetes being the most prevalent at 37 (24.3%) and 35 (23%), respectively. Intraoperative hypotension was experienced by 23 (15.1%) patients, while 129 (84.9%) did not have this issue. Norepinephrine was the most common vasopressor used (25.7%), followed by ephedrine and a combination of norepinephrine and epinephrine. Gender and age groups did not show significant associations with AKI, comorbidities like diabetes, heart failure, and chronic kidney disease (CKD) demonstrated significant relationships with AKI. There was no significant difference in eGFR and serum creatinine baseline levels between patients meeting AKI criteria and those who did not. Conclusions The low overall incidence of AKI in this patient population is encouraging. However, healthcare professionals must be aware of the significant impact of comorbidities such as diabetes, heart failure, and CKD on AKI development. Vigilant monitoring of postoperative kidney function, particularly serum creatinine levels within the first 48 hours, is essential for early detection and timely intervention. By understanding and addressing these risk factors, healthcare providers can take proactive steps to prevent and manage AKI in patients undergoing laparotomy, ultimately leading to improved patient outcomes and reduced healthcare costs.

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.