Risk factors for postoperative acute kidney injury after major abdominal surgery

AIM

Acute kidney injury (AKI) worsens the outcome in a significant number of hospitalized patients. Risk models mainly address cardiac surgery, while significantly less attention is paid to AKI after major abdominal surgery (MAS). This study aims to evaluate the incidence, along with risk factors, and intrahospital outcomes of AKI after MAS.

MATERIAL AND METHODS

Our retrospective study included 200 adult patients treated with MAS (in the same institution). Exclusion criteria were obstructive nephropathy, contrast-induced nephropathy, and dialysis dependence whether due to end-stage renal disease (ESRD) or AKI before MAS. Data on preoperative, intraoperative, as well as postoperative variables were collected from patients' medical history and electronic medical records.

RESULTS

AKI was diagnosed in 33 (16.5%) patients, with 2 patients treated with hemodialysis. The multivariate logistic regression model showed that the number of intraoperative blood transfusions (p = 0.01), pneumonia (p < 0.001), and vasoactive drug use (p = 0.02) were independently associated with postoperative AKI. Each blood transfusion administered increased the risk of developing AKI by 1.41, vasoactive drug use by 4.13, and the risk of AKI in those with pneumonia was 15.32 times higher. The lethal outcome was observed significantly more frequently in patients with AKI (39.4 vs. 4.8%, p < 0.001).

CONCLUSION

Identification of independent predictors of AKI after MAS such as the number of transfusions during surgery, sepsis, pneumonia, and the need for vasoactive drug therapy could help prevent AKI and lower the probability of lethal outcomes after MAS.

Evaluation of the Renal Angina Index to Predict the Development of Acute Kidney Injury in Children With Sepsis Who Live in Middle-Income Countries

OBJECTIVE

The renal angina index (RAI) provides a clinically feasible and applicable tool to identify critically ill children at risk of severe acute kidney injury (AKI) in high-income countries. Our objective was to evaluate the performance of the RAI as a predictor of the development of AKI in children with sepsis in a middle-income country and its association with unfavorable outcomes.

METHODS

This is a retrospective cohort study in children with sepsis hospitalized in the pediatric intensive care unit (PICU) between January 2016 and January 2020. The RAI was calculated 12 hours after admission to predict the development of AKI and at 72 hours to explore its association with mortality, the need for renal support therapy, and PICU stay.

RESULTS

We included 209 PICU patients with sepsis with a median age of 23 months (interquartile range, 7-60). We found that 41.1% of the cases (86/209) developed de novo AKI on the third day of admission (KDIGO 1, 24.9%; KDIGO 2, 12.9%; and KDIGO 3, 3.3%).Overall mortality was 8.1% (17/209), higher in patients with AKI (7.7% vs 0.5%, P < 0.01). The RAI on admission was able to predict the presence of AKI on day 3 (area under the curve (AUC), 0.87; sensitivity, 94.2%; specificity, 100%; P < 0.01), with a negative predictive value greater than 95%. An RAI greater than 8 at 72 hours was associated with a greater risk of mortality (adjusted odds ratio [aOR], 2.6; 95% confidence interval [CI], 2.0-3.2; P < 0.01), a need for renal support therapy (aOR, 2.9; 95% CI, 2.3-3.6; P < 0.01), and a PICU stay of more than 10 days (aOR, 1.54; 95% CI, 1.1-2.1; P < 0.01).

CONCLUSIONS

The RAI on the day of admission is a reliable and accurate tool for predicting the risk of developing AKI on day 3, in critically ill children with sepsis in a limited resource context. A score greater than eight 72 hours after admission is associated with a higher risk of death, the need for renal support therapy, and PICU stay.

Renal replacement therapy initiation strategies in comatose patients with severe acute kidney injury: a secondary analysis of a multicenter randomized controlled trial

PURPOSE

The effect of renal replacement therapy (RRT) in comatose patients with acute kidney injury (AKI) remains unclear. We compared two RRT initiation strategies on the probability of awakening in comatose patients with severe AKI.

METHODS

We conducted a post hoc analysis of a trial comparing two delayed RRT initiation strategies in patients with severe AKI. Patients were monitored until they had oliguria for more than 72 h and/or blood urea nitrogen higher than 112 mg/dL and then randomized to a delayed strategy (RRT initiated after randomization) or a more-delayed one (RRT initiated if complication occurred or when blood urea nitrogen exceeded 140 mg/dL). We included only comatose patients (Richmond Agitation-Sedation scale [RASS] < - 3), irrespective of sedation, at randomization. A multi-state model was built, defining five mutually exclusive states: death, coma (RASS < - 3), incomplete awakening (RASS [- 3; - 2]), awakening (RASS [- 1; + 1] two consecutive days), and agitation (RASS >  + 1). Primary outcome was the transition from coma to awakening during 28 days after randomization.

RESULTS

A total of 168 comatose patients (90 delayed and 78 more-delayed) underwent randomization. The transition intensity from coma to awakening was lower in the more-delayed group (hazard ratio [HR] = 0.36 [0.17-0.78]; p = 0.010). Time spent awake was 10.11 days [8.11-12.15] and 7.63 days [5.57-9.64] in the delayed and the more-delayed groups, respectively. Two sensitivity analyses were performed based on sedation status and sedation practices across centers, yielding comparable results.

CONCLUSION

In comatose patients with severe AKI, a more-delayed RRT initiation strategy resulted in a lower chance of transitioning from coma to awakening.

Acute Kidney Injury Following Transcatheter Aortic Valve Implantation-A Contemporary Perspective of Incidence, Predictors, and Outcomes

BACKGROUND

Acute kidney injury (AKI) is a known complication following transcatheter aortic valve implantation (TAVI), associated with increased morbidity and mortality. Most of this data relates to higher-risk patients with early-generation TAVI valves. With TAVI now established as a safe and cost-effective procedure for low-risk patients, there is a distinct need for updated analysis. We aimed to assess the incidence, predictors, and outcomes of AKI in a contemporary cohort of TAVI patients, concurrently examining the role of temporal evolution on AKI.

METHOD

A total of 2,564 patients undergoing TAVI from 2008-2023 included in the Alfred-Cabrini-Epworth (ACE) TAVI Registry were analysed. Patients were divided into AKI and no AKI groups. Outcomes were reported according to the Valve Academic Research Consortium-3 (VARC-3) criteria.

RESULTS

Of 2,564 patients, median age 83 (78-87) years, 57.4% men and a median Society of Thoracic Surgeons score of 3.6 (2.4-5.5), 163 (6.4%) patients developed AKI with incidence falling from 9.7% between 2008-2014 to 6% between 2015-2023 (p=0.022). On multivariable analysis, independent predictors of AKI were male sex (adjusted odds ratio [aOR] 1.89, p=0.005), congestive cardiac failure (aOR 1.52, p=0.048), estimated glomerular filtration rate 30-59 (aOR: 2.79, p<0.001), estimated glomerular filtration rate <30 (aOR 8.65, p<0.001), non-femoral access (aOR 5.35, p<0.001), contrast volume (aOR 1.01, p<0.001), self-expanding valve (aOR 1.60, p=0.045), and bleeding (aOR 2.88, p=0.005). Acute kidney injury was an independent predictor of 30-day (aOR: 6.07, p<0.001) and 12-month (aOR: 3.01, p=0.002) mortality, an association that remained consistent when excluding TAVIs performed prior to 2015.

CONCLUSIONS

Acute kidney injury remains a relatively common complication of TAVI, associated with significant morbidity and mortality even in less comorbid, contemporary practice patients.

Ambient heat and acute kidney injury: case-crossover analysis of 1 354 675 automated e-alert episodes linked to high-resolution climate data

BACKGROUND

As global temperatures continue to rise, the effects of ambient heat on acute kidney injury (AKI) are of growing concern. We used a novel nationwide electronic alert (e-alert) system to detect increases in AKI risk associated with high temperatures.

METHODS

We used a case-crossover design to link 1 354 675 AKI episodes occurring in England between April and September in years 2017-2021 to daily maximum temperature data at postcode sector level. AKI episode data were obtained from the UK Renal Registry. There were no further inclusion or exclusion criteria. Conditional logistic regression employing distributed lag non-linear models was used to assess odds of AKI episode on case days compared with day-of-week matched control days. Effects during heatwaves were also assessed using heat-episode analysis.

FINDINGS

There were strongly increased odds of AKI episode associated with high temperatures, with odds ratio (OR) 1·623 (95% CI 1·319-1·997) on a day of temperature 32°C compared with one of 17°C, the effects being strongest on a lag of 1 day. There was an OR of 1·020 (1·019-1·020) per 1°C increase in temperature above 17°C. The odds of a heat-related AKI episode were similar between AKI stages 1 and 2, but considerably lower for stage 3 events. A 7-day heatwave in July 2021 was associated with a 28·6% increase in AKI counts (95% CI 26·5-30·7).

INTERPRETATION

Heat-related AKI is a growing public health challenge. As even small changes in renal function can affect patient outcomes, susceptible individuals should be advised to take preventive measures whenever hot weather is forecast. Use of an e-alert system allows effects in milder cases that do not require secondary care to also be detected.

FUNDING

National Institute for Health and Care Research (NIHR).

Potential Predictors for Deterioration of Renal Function After Transfusion

BACKGROUND

Transfusion of packed red blood cells (pRBCs) is still associated with risks. This study aims to determine whether renal function deterioration in the context of individual transfusions in individual patients can be predicted using machine learning. Recipient and donor characteristics linked to increased risk are identified.

METHODS

This study was registered at ClinicalTrials.gov (NCT05466370) and was conducted after local ethics committee approval. We evaluated 3366 transfusion episodes from a university hospital between October 31, 2016, and August 31, 2020. Random forest models were tuned and trained via Python auto-sklearn package to predict acute kidney injury (AKI). The models included recipients' and donors' demographic parameters and laboratory values, donor questionnaire results, and the age of the pRBCs. Bootstrapping on the test dataset was used to calculate the means and standard deviations of various performance metrics.

RESULTS

AKI as defined by a modified Kidney Disease Improving Global Outcomes (KDIGO) criterion developed after 17.4% transfusion episodes (base rate). AKI could be predicted with an area under the curve of the receiver operating characteristic (AUC-ROC) of 0.73 ± 0.02. The negative (NPV) and positive (PPV) predictive values were 0.90 ± 0.02 and 0.32 ± 0.03, respectively. Feature importance and relative risk analyses revealed that donor features were far less important than recipient features for predicting posttransfusion AKI.

CONCLUSIONS

Surprisingly, only the recipients' characteristics played a decisive role in AKI prediction. Based on this result, we speculate that the selection of a specific pRBC may have less influence than recipient characteristics.

Advances in pediatric acute kidney injury pathobiology: a report from the 26th Acute Disease Quality Initiative (ADQI) conference

BACKGROUND

In the past decade, there have been substantial advances in our understanding of the pathobiology of pediatric acute kidney injury (AKI). In particular, animal models and studies focused on the relationship between kidney development, nephron number, and kidney health have identified a number of heterogeneous pathophysiologies underlying AKI. Despite this progress, gaps remain in our understanding of the pathobiology of pediatric AKI.

METHODS

During the 26th Acute Disease Quality Initiative (ADQI) Consensus conference, a multidisciplinary group of experts discussed the evidence and used a modified Delphi process to achieve consensus on recommendations for opportunities to advance translational research in pediatric AKI. The current state of research understanding as well as gaps and opportunities for advancement in research was discussed, and recommendations were summarized.

RESULTS

Consensus was reached that to improve translational pediatric AKI advancements, diverse teams spanning pre-clinical to epidemiological scientists must work in concert together and that results must be shared with the community we serve with patient involvement. Public and private research support and meaningful partnerships with adult research efforts are required. Particular focus is warranted to investigate the pediatric nuances of AKI, including the effect of development as a biological variable on AKI incidence, severity, and outcomes.

CONCLUSIONS

Although AKI is common and associated with significant morbidity, the biologic basis of the disease spectrum throughout varying nephron developmental stages remains poorly understood. An incomplete understanding of factors contributing to kidney health, the diverse pathobiologies underlying AKI in children, and the historically siloed approach to research limit advances in the field. The recommendations outlined herein identify gaps and outline a strategic approach to advance the field of pediatric AKI via multidisciplinary translational research.

Acute Kidney Injury in Neonatal Hypoxic-Ischemic Encephalopathy Patients Treated with Therapeutic Hypothermia: Incidence and Risk Factors

Studies in infants with hypoxic-ischemic encephalopathy (HIE) due to perinatal asphyxia have generally focused on neurological outcomes. Although acute kidney injury (AKI) rate decreased in advent of therapeutic hypothermia (TH), it is still a common and important entity. In this retrospective study, we aimed to investigate the risk factors for AKI in HIE patients treated with hypothermia. Infants treated with TH due to HIE were reviewed retrospectively and infants who developed AKI and not were compared. Ninety-six patients were enrolled in the study. AKI developed in 27 (28%) patients and 4 (14.8%) of them were stage III AKI. In the AKI group, gestational age of the patients was significantly higher (p = 0.035), the 1st minute Apgar score was significantly lower (p = 0.042), and convulsions (p = 0.002), amplitude-integrated electroencephalography disorders (p = 0.025), sepsis (p = 0.017), need for inotropic therapy (p = 0.001), need of invasive mechanical ventilation (p = 0.03), and systolic dysfunction in echocardiography (p = 0.022) were significantly higher. In logistic regression tests, Apgar score at the 1st minute was found to be independent risk factor for developing AKI. AKI has the potential to worsen the neurological damage and correlates with morbidities of perinatal asphyxia. It is important to determine the incidence and risk factors for developing AKI in this delicate group of patients to prevent further renal damage.

Prognostic significance of acute kidney injury stage 1B in hospitalized patients with cirrhosis: A US nationwide study

Understanding the prognostic significance of acute kidney injury (AKI) stage 1B [serum creatinine (sCr) ≥1.5 mg/dL] compared with stage 1A (sCr < 1.5 mg/dL) in a US population is important as it can impact initial management decisions for AKI in hospitalized cirrhosis patients. Therefore, we aimed to define outcomes associated with stage 1B in a nationwide US cohort of hospitalized cirrhosis patients with AKI. Hospitalized cirrhosis patients with AKI in the Cerner-Health-Facts database from January 2009 to September 2017 (n = 6250) were assessed for AKI stage 1 (≥1.5-2-fold increase in sCr from baseline) and were followed for 90 days for outcomes. The primary outcome was 90-day mortality; secondary outcomes were in-hospital AKI progression and AKI recovery. Competing-risk multivariable analysis was performed to determine the independent association between stage 1B, 90-day mortality (liver transplant as a competing risk), and AKI recovery (death/liver transplant as a competing risk). Multivariable logistic regression analysis was performed to determine the independent association between stage 1B and AKI progression. In all, 4654 patients with stage 1 were analyzed: 1A (44.3%) and 1B (55.7%). Stage 1B patients had a significantly higher cumulative incidence of 90-day mortality compared with stage 1A patients, 27.2% versus 19.7% ( p < 0.001). In multivariable competing-risk analysis, patients with stage 1B (vs. 1A) had a higher risk for mortality at 90 days [sHR 1.52 (95% CI 1.20-1.92), p = 0.001] and decreased probability for AKI recovery [sHR 0.76 (95% CI 0.69-0.83), p < 0.001]. Furthermore, in multivariable logistic regression analysis, AKI stage 1B (vs. 1A) was independently associated with AKI progression, OR 1.42 (95% CI 1.14-1.72) ( p < 0.001). AKI stage 1B patients have a significantly higher risk for 90-day mortality, AKI progression, and reduced probability of AKI recovery compared with AKI stage 1A patients. These results could guide initial management decisions for AKI in hospitalized patients with cirrhosis.

Pre-existing chronic kidney disease, aetiology of acute kidney injury and infection do not affect renal outcome and mortality

BACKGROUND

We aimed to study the role of aetiology, pre-existing chronic kidney disease (CKD) and infections in acute kidney injury (AKI) on renal outcome and mortality.

METHODS

This retrospective study analysed patients with AKI admitted to a university nephrology department from January 1st, 2020 through December 31st, 2020. Aetiology of AKI, underlying renal disease in case of pre-existing CKD and presence of infections were assessed. Development of renal function and risk of death were studied with follow-up until January 31st, 2023.

RESULTS

Of 1402 patients screened, 432 patients (30.8%, 67.9 ± 15.4 years) fulfilled the inclusion criteria, half of the population presented with advanced CKD. Even though CKD patients were more often in need of chronic dialysis at time of discharge (6.9% vs 4.5%, p < .001), duration of hospital stay was shorter and in-hospital mortality tended to be lower when compared to AKI without prior renal disease. Neither aetiology of AKI nor pre-existing CKD had an impact on the combined endpoint of end-stage kidney disease and mortality (log rank 0.433 and 0.909). Overall, septic patients showed the highest in-hospital mortality (23.5%) and longest hospital stay (30.0 ± 22.8 days, p < .001), while patients with urosepsis had the shortest hospitalisation time (9.7 days) with lowest risk for dialysis (4.4%). Of note, outcome did not differ in patients with AKI when considering the infectious status.

CONCLUSIONS

Overall renal outcome and mortality in AKI patients were not affected by the cause of AKI, pre-existent CKD or infectious status. Only severity of AKI had a negative impact on outcome.

Acute kidney injury in multiple myeloma patients undergoing autologous hematopoietic stem cell transplant: a cohort study

BACKGROUND

Autologous hematopoietic stem cell transplant plays an important role in multiple myeloma (MM) treatment. Increasing incidence of MM and growing awareness of acute kidney injury (AKI) as a complication of hematopoietic stem cell transplant results in the need to better understand AKI in these patients. We aimed to evaluate incidence, risk factors and 5-year prognostic impact of AKI in MM patients undergoing autologous hematopoietic stem cell transplant.

METHODS

Retrospective cohort study. AKI was defined by the KDIGO classification using creatinine and urinary output criteria. We used survival analysis methods considering competing events for risk factors and disease-free survival, Cox proportional regression for overall survival and stepwise regression methods for multivariable models.

RESULTS

We analyzed data regarding 143 patients. The cumulative incidence of AKI and moderate-to-severe AKI was 49.7% and 14.1%, respectively. Factors with independent impact on AKI were obesity (HR: 1.83, 95% CI 1.07-3.11; p = 0.026), Hematopoietic cell transplantation-specific comorbidity index (HCT-CI) ≥ 2 (HR: 1.85, 95% CI 1.08-3.17), chronic kidney disease (CKD) (HR: 2.06, 95% CI 1.05-4.04), amyloidosis (HR: 2.25, 95% CI 1.25-4.06), mucositis grade 3-4 (HR: 2.19, 95% CI 1.25-3.86) and exposure to nephrotoxic drugs (HR: 2.0856, 95% CI 1.04-4.19). Moderate-to-severe AKI had an impact (HR: 1.62, 95% CI 1.15-2.31) on 5-year overall survival.

CONCLUSION

Acute kidney injury affects almost half of MM patients undergoing autologous hematopoietic stem cell transplantation, and reduction in urinary output allows early diagnosis in almost a quarter of the patients. Obesity, HCT-CI ≥ 2, CKD, amyloidosis, mucositis grade 3-4 and exposure to nephrotoxic drugs are significant risk factors. Moderate-to-severe AKI is associated with lower 5-year overall survival.

Cardiorenal Syndrome Type 3 Review

The management of patients with complex comorbidity involving several organ systems can use an approach focused on each organ system independently or can use an approach trying to integrate various injuries and dysfunction into a single syndrome. Cardiorenal syndromes can develop with an initial injury to either the heart or kidney and then sequential involvement of the second organ. This can occur acutely or chronically. Cardiorenal syndrome type 3 is defined by acute renal injury with subsequent cardiac injury and/or dysfunction. Studies on these patients must use strict inclusion criteria. Pavan reported information on 100 patients with acute kidney injury in India to determine the frequency of cardiorenal syndrome type 3. He excluded patients with significant prior comorbidity. The most frequent causes of acute kidney injury in these patients were drug toxicity, gastroenteritis with volume contraction, and obstetrical complications. This study included 100 patients with acute kidney injury, and 29 developed cardiorenal syndrome type 3. Important outcomes included frequent mortality and chronic renal failure. Other studies have reported that cardiorenal syndrome type 3 occurs relatively infrequently. The analysis of large data bases has demonstrated that the development of acute kidney injury in hospitalized patients has important consequences, including the development of heart failure and increased mortality, but the complexity of these cohorts makes it difficult to determine the time course for the development of multisystem disorders. The pathogenesis of cardiorenal syndrome type 3 involves mitochondrial dysfunction, immune dysregulation, and ischemia-reperfusion. Cardiac events occur secondary to fluid overload, electrolyte disorders, and uremic toxins. These patients need increased attention during hospitalization and outpatient management in an effort to slow the progression of the primary disorder and treat complications.

The prevalence of acute kidney injury in patients with community-acquired pneumonia who required mechanical ventilation

BACKGROUND

Community-acquired pneumonia (CAP) is a common reason for intensive care unit (ICU) admission and sepsis. Acute kidney injury (AKI) is a frequent complication of community-acquired pneumonia and is associated with increased short- and long-term morbidity and mortality and healthcare costs.

OBJECTIVE

Describe the prevalence of AKI in patients with CAP requiring mechanical ventilation and evaluate its association with inhospital mortality.

DESIGN

Retrospective cohort.

SETTING

Intensive care unit.

PATIENTS AND METHODS

We included patients with CAP on mechanical ventilation. Patients were categorized according to the development of AKI in the first 24 hours of ICU admission using the Kidney Disease Improving Global Outcomes (KDIGO) classification from no AKI, stage 1 AKI, stage 2 AKI, and stage 3 AKI.

MAIN OUTCOME MEASURES

The primary outcome was hospital mortality. Secondary outcomes were ICU mortality, hospital and ICU length of stay, ventilation duration, tracheostomy, and renal replacement therapy requirement.

RESULTS

Of 1536 patients included in the study, 829 patients (54%) had no AKI while 707 (46%) developed AKI. In-hospital mortality was 288/829 (34.8%) for patients with no AKI, 43/111 (38.7%) for stage 1 AKI, 86/216 (40%) for stage 2 AKI, and 196/380 (51.7%) for stage 3 AKI (P<.0001). Multivariate analysis revealed that stages 1, 2, or 3 AKI compared to no AKI were not independently associated with in-hospital mortality. Older age, vasopressor use; decreased Glasgow coma scale, PaO2/Fio2 ratio and platelet count, increased bilirubin, lactic acid and INR were associated with increased mortality while female sex was associated with reduced mortality.

CONCLUSION

Among mechanically ventilated patients with CAP, AKI was common and was associated with higher crude mortality. The higher mortality could not be attributed alone to AKI, but rather appeared to be related to multi-organ dysfunction.

LIMITATIONS

Single-center retrospective study with no data on baseline serum creatinine and the use of estimated baseline creatinine distributions based on the MDRD (Modification of Diet in Renal Disease)equation which may lead to an overestimation of AKI. Second, we did not have data on the microbiology of pneumonia, appropriateness of antibiotic therapy or the administration of other medications that have been demonstrated to be associated with AKI.

Risk of kidney and liver diseases after COVID-19 infection: A systematic review and meta-analysis

COVID-19 is not only associated with substantial acute liver and kidney injuries, but also with an elevated risk of post-acute sequelae involving the kidney and liver system. We aimed to investigate whether COVID-19 exposure increases the long-term risk of kidney and liver disease, and what are the magnitudes of these associations. We searched PubMed, Embase, Web of Science, ClinicalTrials.gov, and the Living Overview of the Evidence COVID-19 Repository for cohort studies estimating the association between COVID-19 and kidney and liver outcomes. Random-effects meta-analyses were performed to combine the results of the included studies. We assessed the certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. Fifteen cohort studies with more than 32 million participants were included in the systematic review COVID-19 was associated with a 35% greater risk of kidney diseases (10 more per 1000 persons; low certainty evidence) and 54% greater risk of liver disease (3 more per 1000 persons; low certainty evidence). The absolute increases due to COVID-19 for acute kidney injury, chronic kidney disease, and liver test abnormality were 3, 8, and 3 per 1000 persons, respectively. Subgroup analyses found no differences between different type of kidney and liver diseases. The findings provide further evidence for the association between COVID-19 and incident kidney and liver conditions. The absolute magnitude of the effect of COVID-19 on kidney and liver outcomes was, however, relatively small.

Renal tissue oxygenation and development of AKI in preterm neonates born < 32 weeks' gestational age in the first week of age

OBJECTIVE

To evaluate the relationship between regional renal saturation of oxygen (RrSO2) changes and serum creatinine (SCr) during the first eight days of age for preterm neonates born < 32 weeks' gestational age.

DESIGN

Post-hoc analysis of multicenter prospectively measured neonatal RrSO2 values collected during the first 8 days of age in neonates born at < 32 weeks' gestation. Acute kidney injury (AKI) was defined by the neonatal modified Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Variables were compared between groups of neonates with and with AKI.

RESULTS

One hundred nine neonates were included and 561 SCr values were obtained. Eight participants developed AKI by SCr criteria. A 10-percentage point increase in mean %RrSO2 was associated with a 40% decrease in risk of AKI (95%CI: 9.6-61%; p = 0.016).

CONCLUSIONS

Increases in mean %RrSO2 in neonates born at < 32 weeks' GA were associated with a decreased risk of AKI. These findings support the design of further prospective trials utilizing RrSO2 monitoring to evaluate new therapies or clinical protocols to prevent and treat neonatal AKI.

Septic acute kidney injury and gut microbiome: Should we change our approach?

Incidence of acute kidney injury (AKI) remained relatively stable over the last decade and the adjusted risks for it and mortality are similar across different continents and regions. Also, the mortality of septic-AKI can reach 70% in critically-ill patients. These sole facts can give rise to a question: is there something we do not understand yet? Currently, there are no specific therapies for septic AKI and the treatment aims only to maintain the mean arterial pressure over 65mmHg by ensuring a good fluid resuscitation and by using vasopressors, along with antibiotics. On the other hand, there is an increased concern about the different hemodynamic changes in septic AKI versus other forms and the link between the gut microbiome and the severity of septic AKI. Fortunately, progress has been made in the form of administration of pre- and probiotics, short chain fatty acids (SCFA), especially acetate, and also broad-spectrum antibiotics or selective decontaminants of the digestive tract in a successful attempt to modulate the microbial flora and to decrease both the severity of AKI and mortality. In conclusion, septic-AKI is a severe form of kidney injury, with particular hemodynamic changes and with a strong link between the kidney and the gut microbiome. By modulating the immune response we could not only treat but also prevent severe forms. The most difficult part is to categorize patients and to better understand the key mechanisms of inflammation and cellular adaptation to the injury, as these mechanisms can serve in the future as target therapies.

Renal Replacement Therapy in Cirrhosis: A Contemporary Review

Acute kidney injury is a common complication of decompensated cirrhosis, frequently requires hospitalization, and carries a high short-term mortality. This population experiences several characteristic types of acute kidney injury: hypovolemic-mediated (prerenal), ischemic/nephrotoxic-mediated (acute-tubular necrosis), and hepatorenal syndrome. Prerenal acute kidney injury is treated with volume resuscitation. Acute-tubular necrosis is treated by optimizing perfusion pressure and discontinuing the offending agent. Hepatorenal syndrome, a unique physiology of decreased effective arterial circulation leading to renal vasoconstriction and ultimately acute kidney injury, is treated with plasma expansion with albumin and splanchnic vasoconstrictors such as terlipressin or norepinephrine. Common acute stressors such as bleeding, infection, and volume depletion often contribute to multifactorial acute kidney injury. Even with optimal medical management, many clinicians are faced with the challenge of initiating renal replacement therapy in these patients. This article reviews the epidemiology, indications, and complex considerations of renal replacement therapy for acute kidney injury in decompensated cirrhosis.

Mortality Factors in Crush Syndrome

BACKGROUND

Crush Syndrome is a major cause of morbidity and mortality following large-scale catastrophic earthquakes. Since there are no randomized controlled studies on Crush Syndrome, knowledge on this subject is limited to expert experience. The primary objective is to analyze the epidemiological and demographic characteristics, clinical outcomes, and mortality factors of earthquake victims after the Pazarcik and Elbistan earthquakes on February 6, 2023.

METHODS

This cross-sectional and observational retrospective study evaluated 610 earthquake victims who presented to our center between February 6 and April 30, 2023. Among these patients, 128 with Crush Syndrome were included in the study. Patient information was gathered from hospital records during their stay and from national registries upon referral. The primary outcome was to identify risk factors for mortality. Demographic and laboratory data were analyzed by acute kidney injury (AKI) stages; mortality-affecting factors were identified through regression analysis.

RESULTS

Of the 128 Crush Syndrome patients (100 adults, 28 children), 64 were female. The AKI rate was 32.8%. Among patients with AKI, the frequency of hemodialysis requirement was 69%, and the mortality rate was 14.2%. The overall mortality rate for patients with Crush Syndrome was 4.6%, compared to 3.9% (19/482) in earthquake victims without Crush Syndrome (p=0.705). Notably, low systolic blood pressure at admission was the only factor significantly affecting mortality in Crush Syndrome patients (Hazard Ratio [HR]: 1.088, p=0.021, 95% Confidence Interval [CI]).

CONCLUSION

Our study highlights low systolic blood pressure upon admission as a significant risk factor for increased mortality in Crush Syndrome patients. This finding may contribute to the literature by emphasizing the importance of monitoring blood pressure under rubble and administering more aggressive fluid therapy to patients with low systolic blood pressure.

Development and validation of a deep interpretable network for continuous acute kidney injury prediction in critically ill patients

Early detection of acute kidney injury (AKI) may provide a crucial window of opportunity to prevent further injury, which helps improve clinical outcomes. This study aimed to develop a deep interpretable network for continuously predicting the 24-hour AKI risk in real-time and evaluate its performance internally and externally in critically ill patients. A total of 21,163 patients' electronic health records sourced from Beth Israel Deaconess Medical Center (BIDMC) were first included in building the model. Two external validation populations included 3025 patients from the Philips eICU Research Institute and 2625 patients from Zhongda Hospital Southeast University. A total of 152 intelligently engineered predictors were extracted on an hourly basis. The prediction model referred to as DeepAKI was designed with the basic framework of squeeze-and-excitation networks with dilated causal convolution embedded. The integrated gradients method was utilized to explain the prediction model. When performed on the internal validation set (3175 [15 %] patients from BIDMC) and the two external validation sets, DeepAKI obtained the area under the curve of 0.799 (95 % CI 0.791-0.806), 0.763 (95 % CI 0.755-0.771) and 0.676 (95 % CI 0.668-0.684) for continuousAKI prediction, respectively. For model interpretability, clinically relevant important variables contributing to the model prediction were informed, and individual explanations along the timeline were explored to show how AKI risk arose. The potential threats to generalisability in deep learning-based models when deployed across health systems in real-world settings were analyzed.

Tubule dysfunction and injury and future risk of sepsis-associated acute kidney injury

BACKGROUND

Novel biomarkers can quantify both kidney tubule function, including proximal tubule reabsorptive (urine α-1 microglobulin (uα1m)) and tubule protein synthesis capacities (urine uromodulin (uUMOD)), and tubular injury (urine neutrophil gelatinase-associated lipocalin (uNGAL)). In a blood pressure trial, we reported that lower reabsorptive and synthetic protein capacity at times of health predicted future risk of acute kidney injury (AKI), but most AKI was related to hemodynamic causes in this trial. Associations between tubular function and injury and future AKI related to other causes is unknown.

MATERIALS AND METHODS

We performed a case-control study in REGARDS, a population-based cohort study, among participants who provided urine at the baseline visit. We matched each septic AKI case by age, sex, race, and time from baseline to hospital admission 1 : 1 to a participant with sepsis who did not develop AKI (controls). Using conditional logistic regression, we evaluated the associations of uα1m, uUMOD, urine ammonium, and uNGAL with septic AKI.

RESULTS

Mean age was 69 ± 8 years, 44% were female, and 39% were Black participants. Median baseline eGFR among cases and controls was 73 (55, 90) and 82 (65, 92) mL/min/1.73m2, and median albuminuria was 19 (8, 87) vs. 9 (5, 22) mg/g, respectively. No independent associations were observed between the tubule function or injury markers and subsequent risk of septic AKI once models were adjusted for baseline albuminuria, estimated glomerular filtration rate, and other risk factors.

CONCLUSION

Among community participants, tubule function and injury markers at times of health were not independently associated with future risk of septic AKI.

Systemic inflammation response index as a prognostic factor for patients with sepsis-associated acute kidney injury: a retrospective observational study

OBJECTIVE

To assess the association between the systemic inflammation response index (SIRI) and the prognosis in patients with sepsis-associated acute kidney injury (SA-AKI).

METHODS

In this observational study, adult patients with SA-AKI were categorized into three groups based on SIRI tertiles. Survival outcomes were compared across the three groups using Kaplan-Meier survival curves. Various Cox proportional hazards regression models were developed to determine the association between the SIRI and mortality in patients with SA-AKI. Subgroup analyses were also performed to explore the association between different SIRI tertiles and all-cause mortality.

RESULTS

After adjusting for several confounders, the second SIRI tertile (2.5 < SIRI < 7.6) was found to be an independent risk factor for 30-day mortality [hazard ratio (95% confidence interval): 1.19 (1.01-1.40)], 90-day mortality [1.22 (1.06-1.41)], and 365-day mortality [1.24 (1.09-1.40)]. Furthermore, high SIRI values were associated with increased risks of 30-day, 90-day, and 365-day mortality in patients with SA-AKI across all three models. The third tertile showed a significant association with adverse outcomes in most subgroups.

CONCLUSIONS

The SIRI serves as a comprehensive biomarker for predicting all-cause mortality of critically ill patients with SA-AKI.

Cholemic Nephropathy: Role in Acute Kidney Injury in Cholestasis and Cirrhosis

The concept of structural kidney damage and renal dysfunction as a result of jaundice attracted attention in the medical community in the early and mid-20th century. The postulated doctrine of the time was that the excretion of elevated concentrations of bile results in bile-stained casts occupying collecting and distal convoluted tubules, degeneration of tubular epithelium, and decreased renal function. Compared to the hepatorenal syndrome, the poster child of hepatology and nephrology collaboration, the notion of structural kidney damage and renal dysfunction as a result of cholemia lost its traction and has almost disappeared from modern textbooks. Today, cholemic nephropathy is experiencing a renaissance, with multiple case reports and case series of jaundiced patients with kidney dysfunction and evidence of bile acid casts upon histologic examination. Published cases include acute hepatitis, chronic liver injury, cirrhosis, and obstructive etiologies. Diagnosis of cholemic nephropathy is based on histological examination, typically showing intraluminal bile casts predominantly located in the distal tubules. In common bile duct-ligated mice, the histomorphological and functional alterations of cholemic nephropathy mimic those seen in humans. Some argue against the concept of cholemic nephropathy and postulate that bile casts are a secondary phenomenon. What we need are carefully designed trials to establish diagnostic criteria and subsequently translate this knowledge into evidence-based therapies.

Therapeutic effects of the alkaline extract of leaves of Sasa sp. and elucidation of its mechanism in acute kidney injury

Acute kidney injury (AKI), a common complication in hospitalized patients, is associated with high morbidity and mortality rates. However, there are currently no approved or effective therapeutics for AKI. AKI is primarily caused by ischemia/reperfusion (I/R) injury, with oxidative stress from reactive oxygen species (ROS) being a major contributor. This study aimed to evaluate the efficacy of an alkaline extract of the leaves of Sasa sp. (SE) using mouse renal I/R injury and hypoxia/reoxygenation (H/R) models in NRK-52E cells. Renal function parameters were measured, and histopathological evaluations were performed to assess the efficacy of SE. In addition, to determine the mechanisms underlying the effects of SE on renal I/R injury, its effects on malondialdehyde (MDA) of oxidative stress and interleukin (IL)-6 and IL-1β of inflammatory cytokines were evaluated. SE (0.03, 0.3, and 3 g/kg) improved renal function in a dose-dependent manner. In addition, SE ameliorated tubular injury and, reduced IL-6, IL-1β and MDA. Also, SE ameliorated cell death, ROS production, and inflammatory cytokine production in H/R-exposed NRK-52E cells. SE showed antioxidant and anti-inflammatory activities in the AKI. These results indicate the potential of SE as a medicinal compound for the prevention and treatment of AKI.

Cardiopulmonary bypass management and acute kidney injury in cardiac surgery patients

BACKGROUND

Cardiopulmonary bypass (CPB) ensures tissue oxygenation during cardiac surgery. New technology allows continuous registration of CPB variables during the operation. The aim of the present investigation was to study the association between CPB management and the risk of postoperative acute kidney injury (AKI).

METHODS

This observational study based on prospectively registered data included 2661 coronary artery bypass grafting and/or valve patients operated during 2016-2020. Individual patient characteristics and postoperative outcomes collected from the SWEDEHEART registry were merged with CPB variables automatically registered every 20 s during CPB. Associations between CPB variables and AKI were analyzed with multivariable logistic regression models adjusted for patient characteristics.

RESULTS

In total, 387 patients (14.5%) developed postoperative AKI. After adjustments, longer time on CPB and aortic cross-clamp, periods of compromised blood flow during aortic cross-clamp time, and lower nadir hematocrit were associated with the risk of AKI, while mean blood flow, bladder temperature, central venous pressure, and mixed venous oxygen saturation were not. Patient characteristics independently associated with AKI were advanced age, higher body mass index, hypertension, diabetes mellitus, atrial fibrillation, lower left ventricular ejection fraction, estimated glomerular filtration rate <60 or >90 mL/min/m2 , and preoperative hemoglobin concentration below or above the normal sex-specific range.

CONCLUSIONS

To reduce the risk of AKI after cardiac surgery, aortic clamp time and CPB time should be kept short, and low hematocrit and periods of compromised blood flow during aortic cross-clamp time should be avoided if possible.

Predictors of oliguria in post-traumatic acute kidney injury

BACKGROUND

Acute kidney injury is classified by urine output into non-oliguric and oliguric variants. Non-oliguric acute kidney injury has lower morbidity and mortality and accounts for up to 64% of acute kidney injury in hospitalized patients. However, the incidence of non-oliguric acute kidney injury in the trauma population and whether the 2 variants of acute kidney injury share the same risk factors is unknown. We hypothesized that oliguria would be present in the majority of acute kidney injury in severely injured trauma patients and that unique risk factors would predispose patients to the development of oliguria.

METHODS

Patients admitted to the trauma intensive care unit and diagnosed with an acute kidney injury between 2016 to 2021 were identified. Cases were categorized based on urine output into oliguric (<400 mL per day) and non-oliguric (>400 mL per day) disease. Risk factors, management, and outcomes were compared. Logistic regression was used to identify risk factors associated with oliguria.

RESULTS

A total of 227 patients met inclusion criteria. Non-oliguric acute kidney injury accounted for 74% of all cases and was associated with greater survival (78% vs 35.6%, P < .001). Using logistic regression, female sex, vasopressor use, and a greater net fluid balance at 48 hours were all predictive of oliguria (while controlling for age, race, shock index, massive transfusion, operative intervention, cardiac arrest, and nephrotoxic medication exposure).

CONCLUSION

Non-oliguria accounts for the majority of post-traumatic acute kidney injury and is associated with improved survival. Specific risk factors for the development of oliguric acute kidney injury include female sex, vasopressor use, and a higher net fluid balance at 48 hours.

Resistive index as predictor of acute kidney injury in patients with non-ST-segment elevation myocardial infarction

BACKGROUND

Acute kidney injury (AKI) is common in patients with non-ST-segment elevation myocardial infarction (NSTEMI). Early detection of AKI is likely to speed diagnosis and implementation of measures to preserve renal function. To evaluate if renal Doppler resistive index (RI) would predict AKI in patients with NSTEMI on presentation in the emergency department.

METHODS

Patients with NSTEMI at the emergency department were included. The renal Doppler RI was measured. Baseline demographic data and clinical characteristics of patients at admittance were recorded. Based on discharge diagnosis, the patients were divided into AKI group and no-AKI group. Multiple logistic regression analysis was performed to determine predictor variables significantly associated with AKI.

RESULTS

A total of 293 patients were included in the analysis; 44 (15.0%) developed AKI without need for dialysis. There were statistical differences in the age, incidence of diabetes mellitus and cerebrovascular disease, beta-receptor blockers, serum creatinine and renal index between the two groups. Using multivariate logistic regression analysis, age [OR 1.87; 95% confidence interval (CI) 1.595-2.585; p = 0.027], diabetes mellitus (OR 2.007, 95% CI: 1.489-2.793; p = 0.014), serum creatinine (OR 1.817, 95% CI: 1.568-2.319; p = 0.013), and RI (OR 2.168, 95% CI: 1.994-4.019; p = 0.003) predicted AKI in patients with NSTEMI. According to receiver operating characteristic (ROC) analysis, RI showed a significantly increased area under the curve (AUC) compared to serum creatitine (AUC: 0.891 vs 0.679; p < 0.001).

CONCLUSIONS

Renal Doppler RI may be a useful predictor of AKI in patients with NSTEMI in the emergency department.

Timing of renal replacement therapy in patients with sepsis-associated acute kidney injury: A systematic review and meta-analysis

OBJECTIVE

The objective of this study was to evaluate the clinical efficacy of early and delayed renal replacement therapy (RRT) in patients with sepsis-associated acute kidney injury (AKI).

METHODS

We searched three databases (PubMed, Web of Science, and Cochrane) for randomised controlled trials and cohort studies published up to March 28, 2022, and manually searched for relevant references. We included data from adults older than 18 years of age with sepsis-associated AKI. The Newcastle-Ottawa Scale and the Cochrane Risk of Bias tool were used for quality assessment. The primary outcome was 28-day mortality. Relative risk (RR), mean difference (MD), and 95% confidence interval (CI) were used for meta-analysis.

RESULTS

There were a total of 3648 patients from four randomised controlled trials and eight cohort studies. The pooled results indicated that compared to delayed RRT, early RRT had a lower 28-day mortality (RR: 0.72; 95% CI: 0.59-0.88; P = 0.001; I2 = 76%), and this result was robust according to sensitivity analysis, and no significant difference in 90-day mortality (RR: 0.80; 95% CI: 0.64-1.00; P = 0.05; I2 = 82%),180-day mortality (RR: 1.07; 95% CI: 0.93-1.23; P = 0.36; I2 = 0%), length of intensive care unit stay (MD - 0.94; 95% CI -2.43-0.55; P = 0.22; I2 = 0%), length of hospital stay (MD - 1.02; 95% CI -4.21-2.17; P = 0.53; I2 = 0%), and RRT dependence was found among survivors at 28 days (RR: 1.21; 95% CI: 0.73-2.00; P = 0.47; I2 = 0%). Subgroup analysis of 28-day mortality showed that patients with sepsis-associated AKI who received early RRT at Kidney Disease: Improving Global Outcomes stage 2 or Sequential Organ Failure Assessment score ≤12 had a better chance of survival.

CONCLUSIONS

Early RRT may be beneficial to the 28-day short-term survival rate of patients with sepsis-associated AKI in Kidney Disease: Improving Global Outcomes stage 2 and having Sequential Organ Failure Assessment score less than or equal to 12 but has no significant effect on long-term survival, length of intensive care unit stay, the total length of hospital stay, and 28-day RRT dependence of survivors. These results still need to be confirmed by more large-scale randomised controlled studies.

VWF/ADAMTS13 Ratio as a Potential Predictive Biomarker for Acute Kidney Injury Onset in Cirrhosis

AIM

We investigated the von Willebrand factor to ADAMTS13 ratio (von Willebrand factor [VWF]:Ag/ADAMTS13:AC) as a potential biomarker for the outcomes of acute kidney injury (AKI) in liver cirrhosis (LC).

METHODS

This retrospective cross-sectional study included patients with LC who developed AKI (AKI group: n = 91) and patients with LC who did not develop AKI [non-AKI (NAKI) group, n = 91] as a control group. Plasma levels of the von Willebrand factor antigen (Ag) and ADAMTS13 activity (AC) were measured in patients with AKI or NAKI. Moreover, risk factors for onset of AKI, AKI-associated 90-day mortality, and poor AKI treatment response were identified.

RESULTS

The AKI group had a significantly higher VWF:Ag/ADAMTS13:AC than the NAKI group. Values of VWF:Ag/ADAMTS13:AC ≥ 5.7 were identified as risk factors for AKI onset in patients with LC (odds ratio [OR] 2.56; 95% CI 1.26-4.99; p < 0.001). Among patients with AKI, values of VWF:Ag/ADAMTS13:AC ≥ 9.0 were identified as risk factors for 90-day mortality (OR 6.83; 95% CI 2.32-20.10; p < 0.001). Cumulative survival was significantly lower in those with high (≥ 9.0) than in those with low (< 9.0) VWF:Ag/ADAMTS13:AC. Furthermore, values of VWF:Ag/ADAMTS13:AC ≥ 7.4 were identified as risk factors for poor treatment response (OR 4.2; 95% CI 1.39-12.70; p < 0.001). The treatment response rates were significantly higher in those with low (< 7.4) VWF:Ag/ADAMTS13:AC than in those with high (≥ 7.4) VWF:Ag/ADAMTS13:AC.

CONCLUSION

VWF:Ag/ADAMTS13:AC potentially predicts the onset, prognosis, and treatment response of AKI in patients with LC.

Kidney Dysfunction in the Setting of Liver Failure: Core Curriculum 2024

Individuals with liver disease are susceptible to pathophysiological derangements that lead to kidney dysfunction. Patients with advanced cirrhosis and acute liver failure (ALF) are at risk of developing acute kidney injury (AKI). Hepatorenal syndrome type 1 (HRS-1, also called HRS-AKI) constitutes a form of AKI unique to the state of cirrhosis and portal hypertension. Although HRS-1 is a condition primarily characterized by marked renal vasoconstriction and kidney hypoperfusion, other pathogenic processes, such as acute tubular injury and renal vein congestion, can overlap and further complicate the course of HRS-1. ALF can lead to AKI through mechanisms that involve systemic inflammation, direct drug toxicity, or bile acid-induced tubulopathy. In addition, the growing prevalence of nonalcoholic steatohepatitis is changing the spectrum of chronic kidney disease in cirrhosis. In this installment of AJKD's Core Curriculum in Nephrology, we explore the underpinnings of how cirrhosis, ALF, acute cholestasis, and post-liver transplantation can be associated with various forms of acute, subacute, or chronic kidney diseases. We navigate through the recommended therapies for each condition, including supportive care, pharmacological interventions, kidney replacement therapy, and organ transplantation. Finally, key acid-base and electrolyte disorders associated with hepatobiliary disease are also summarized.

l-Carnitine pretreatment ameliorates heat stress-induced acute kidney injury by restoring mitochondrial function of tubular cells

A major complication of heat-related illness is the development of acute kidney injury (AKI) and damage to kidney tubular cells. Because kidney tubular cells use fatty acids as a major energy source, impaired fatty acid oxidation (FAO) may be associated with kidney injury due to heat stress. Carnitine is essential in the transportation of fatty acid into mitochondria for FAO. To date, there has been little attention given to the role of carnitine in heat-related illness and AKI. To evaluate the relationship between carnitine inadequacy and heat-related illness severity or AKI, we examined serum carnitine levels in patients with heat-related illness. We also used heat-stressed mice to investigate the effect of l-carnitine pretreatment on various kidney functions such as mitochondrial activity, proinflammatory changes in kidney macrophages, and histological damage. We observed an elevation in serum acylcarnitine levels, indicating carnitine insufficiency in patients with severe heat-related illness and/or AKI. l-Carnitine pretreatment ameliorated ATP production in murine tubular cell mitochondria and prevented a change in the kidney macrophage population dynamics observed in AKI: a decrease in tissue-resident macrophages, influx of bone marrow-derived macrophages, and change toward proinflammatory M1 polarization. In conclusion, carnitine insufficiency may be closely associated with severe heat-related illness and related AKI. Enhancement of the FAO pathway by l-carnitine pretreatment may prevent heat stress-induced AKI by restoring mitochondrial function.NEW & NOTEWORTHY Enhancing fatty acid oxidation (FAO) after acute kidney injury (AKI) improves renal outcomes. This report shows that carnitine insufficiency, which could inhibit FAO, correlates to severe heat-related illness and AKI in a clinical study. We also demonstrate that administering l-carnitine to mice improves mitochondrial respiratory function and prevents deleterious changes in renal macrophage, resulting in improved renal outcomes of heat-induced AKI. l-Carnitine may be an effective preventive treatment for severe heat-related illness and related AKI.

Urinary proteomics reveals biological processes related to acute kidney injury in Bothrops atrox envenomings

Acute kidney injury (AKI) is a critical systemic complication caused by Bothrops envenoming, a neglected health problem in the Brazilian Amazon. Understanding the underlying mechanisms leading to AKI is crucial for effectively mitigating the burden of this complication. This study aimed to characterize the urinary protein profile of Bothrops atrox snakebite victims who developed AKI. We analyzed three groups of samples collected on admission: healthy subjects (controls, n = 10), snakebite victims who developed AKI (AKI, n = 10), and those who did not evolve to AKI (No-AKI, n = 10). Using liquid-chromatography tandem mass spectrometry, we identified and quantified (label-free) 1190 proteins. A panel of 65 proteins was identified exclusively in the urine of snakebite victims, with 32 exclusives to the AKI condition. Proteins more abundant or exclusive in AKI's urine were associated with acute phase response, endopeptidase inhibition, complement cascade, and inflammation. Notable proteins include serotransferrin, SERPINA-1, alpha-1B-glycoprotein, and NHL repeat-containing protein 3. Furthermore, evaluating previously reported biomarkers candidates for AKI and renal injury, we found retinol-binding protein, beta-2-microglobulin, cystatin-C, and hepcidin to be significant in cases of AKI induced by Bothrops envenoming. This work sheds light on physiological disturbances caused by Bothrops envenoming, highlighting potential biological processes contributing to AKI. Such insights may aid in better understanding and managing this life-threatening complication.

Indexed neutrophil gelatinase associated lipocalin: a novel biomarker for the assessment of acute kidney injury

INTRODUCTION

Acute kidney injury (AKI) is a clinically relevant and common complication among patients with acute coronary syndrome. Neutrophil gelatinase-associated lipocalin (NGAL), secreted from different cells including renal tubules, has been widely studied as an early marker for kidney injury. However, chronic kidney disease (CKD) could impact NGAL levels and alter their predictive performance. Some studies attempted to address this issue by setting different cutoff values for patients with CKD, with limited success to date. Our aim was to evaluate a novel estimated glomerular filtration rate (eGFR)-adjusted "indexed NGAL" and its ability to predict in-hospital AKI among patients with ST elevation myocardial infarction.

METHODS

We performed a prospective, observational, single center study involving patients with ST elevation myocardial infarction admitted to the coronary intensive care unit. Serum samples for baseline NGAL were collected within 24 h following hospital admission. The eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. In-hospital AKI was determined as occurring after ≥ 24 h from admission. To perform an individualized adjustment, we used the result of 24 h NGAL divided by the eGFR measured upon admission to the hospital (Indexed-NGAL; I-NGAL).

RESULTS

Our cohort includes 311 patients, of whom 123 (40%) had CKD, and 66 (21%) suffered in-hospital AKI. NGAL levels as well as I-NGAL levels were significantly higher in patients with AKI (136 vs. 86, p < 0.01 and 3.13 VS. 1.06, p < 0.01, respectively). Multivariate analysis revealed I-NGAL to be independently associated with AKI (OR 1.34 (1.10-1.58), p < 0.01). I-NGAL had a higher predictive ability than simple NGAL results (AUC-ROC of 0.858 vs. 0.778, p < 0.001).

CONCLUSION

Adjusting NGAL values according to eGFR yields a new indexed NGAL value that enables better prediction of AKI regardless of baseline kidney function.

Single-cell RNA sequencing identifies senescence as therapeutic target in rhabdomyolysis-induced acute kidney injury

BACKGROUND

The role of macrophages in the development of rhabdomyolysis-induced acute kidney injury (RM-AKI) has been established, but an in-depth understanding of the changes in the immune landscape could help to improve targeted strategies. Whereas senescence is usually associated with chronic kidney processes, we also wished to explore whether senescence could also occur in AKI and whether senolytics could act on immune cells.

METHODS

Single-cell RNA sequencing was used in the murine glycerol-induced RM-AKI model to dissect the transcriptomic characteristics of CD45+ live cells sorted from kidneys 2 days after injury. Public datasets from murine AKI models were reanalysed to explore cellular senescence signature in tubular epithelial cells (TECs). A combination of senolytics (dasatinib and quercetin, DQ) was administered to mice exposed or not to RM-AKI.

RESULTS

Unsupervised clustering of nearly 17 000 single-cell transcriptomes identified seven known immune cell clusters. Sub-clustering of the mononuclear phagocyte cells revealed nine distinct cell sub-populations differently modified with RM. One macrophage cluster was particularly interesting since it behaved as a critical node in a trajectory connecting one major histocompatibility complex class IIhigh (MHCIIhigh) cluster only present in Control to two MHCIIlow clusters only present in RM-AKI. This critical cluster expressed a senescence gene signature, that was very different from that of the TECs. Senolytic DQ treatment blocked the switch from a F4/80highCD11blow to F4/80lowCD11bhigh phenotype, which correlated with prolonged nephroprotection in RM-AKI.

CONCLUSIONS

Single-cell RNA sequencing unmasked novel transitional macrophage subpopulation associated with RM-AKI characterized by the activation of cellular senescence processes. This work provides a proof-of-concept that senolytics nephroprotective effects may rely, at least in part, on subtle immune modulation.

Characteristics and prognosis of acute renal failure on dialysis in ANCA vasculitis

Renal involvement in ANCA (Anti Neutrophil Cytoplasmic Antigen) vasculitis is common and is associated with increased mortality with a significant risk of progression to end-stage renal disease. The aim of this study is to investigate the epidemiological, clinicopathological, therapeutic and evolutionary characteristics of patients with ANCA vasculitis with acute renal injury, and to evaluate the impact of haemodialysis in the acute phase on mortality and renal recovery. Secondary objectives are to investigate other risk factors that impact on overall and renal survival. 31 patients were included ; the mean follow-up time was 30 months. The mean age was 68.52 years, and the sex ratio 0.72. All patients had acute renal failure, with histology revealing a mixed form in 45% of cases and a sclerotic form in 12.9% of cases. Pulmonary involvement was found in 58% of cases. 71% of patients had ANCA with anti-myeloperoxydase specificity, and 25.8% anti-proteinase 3 specificity. 32.2% of patients required haemodialysis, of which 60% were weaned. As initial treatment, 58.1% of patients received cyclophosphamide and 35.5% rituximab. The relapse rate was 6.5%. Infectious and cardiovascular complications affected more than half of the patients. The mortality rate was 19.35%. Comparing the two groups of patients dialysed in the acute phase and not dialysed, it appears that the overall and renal mortality was comparable. The progression to end-stage renal failure was higher in the dialysis patients. In a multivariate study, the presence of chronic kidney disease in the history and pulmonary involvement were associated with higher mortality.

Recovery of kidney function after acute kidney disease-a multi-cohort analysis

BACKGROUND

There are no consensus definitions for evaluating kidney function recovery after acute kidney injury (AKI) and acute kidney disease (AKD), nor is it clear how recovery varies across populations and clinical subsets. We present a federated analysis of four population-based cohorts from Canada, Denmark and Scotland, 2011-18.

METHODS

We identified incident AKD defined by serum creatinine changes within 48 h, 7 days and 90 days based on KDIGO AKI and AKD criteria. Separately, we applied changes up to 365 days to address widely used e-alert implementations that extend beyond the KDIGO AKI and AKD timeframes. Kidney recovery was based on resolution of AKD and a subsequent creatinine measurement below 1.2× baseline. We evaluated transitions between non-recovery, recovery and death up to 1 year; within age, sex and comorbidity subgroups; between subset AKD definitions; and across cohorts.

RESULTS

There were 464 868 incident cases, median age 67-75 years. At 1 year, results were consistent across cohorts, with pooled mortalities for creatinine changes within 48 h, 7 days, 90 days and 365 days (and 95% confidence interval) of 40% (34%-45%), 40% (34%-46%), 37% (31%-42%) and 22% (16%-29%) respectively, and non-recovery of kidney function of 19% (15%-23%), 30% (24%-35%), 25% (21%-29%) and 37% (30%-43%), respectively. Recovery by 14 and 90 days was frequently not sustained at 1 year. Older males and those with heart failure or cancer were more likely to die than to experience sustained non-recovery, whereas the converse was true for younger females and those with diabetes.

CONCLUSION

Consistently across multiple cohorts, based on 1-year mortality and non-recovery, KDIGO AKD (up to 90 days) is at least prognostically similar to KDIGO AKI (7 days), and covers more people. Outcomes associated with AKD vary by age, sex and comorbidities such that older males are more likely to die, and younger females are less likely to recover.

The Effect of Positive Pressure Ventilation on Acute Kidney Injury in COVID-19 Patients with Acute Respiratory Distress Syndrome: An Observational Study

INTRODUCTION

Acute kidney injury (AKI) is frequent in critically ill COVID-19 patients and is associated with a higher mortality risk. By increasing intrathoracic pressure, positive pressure ventilation (PPV) may reduce renal perfusion pressure by reducing venous return to the heart or by increasing renal venous congestion. This study's aim was to evaluate the association between AKI and haemodynamic and ventilatory parameters in COVID-19 patients with ARDS.

METHODS

This is a single-centre retrospective observational study. Consecutive patients diagnosed with COVID-19 who met ARDS criteria and required invasive mechanical ventilation were enrolled. The relationship between respiratory and haemodynamic parameters influenced by PPV and AKI development was evaluated. AKI was defined according to KDIGO criteria. AKI recovery was evaluated a month after ICU admission and patients were classified as "recovered," if serum creatinine (sCr) value returned to baseline, or as having "acute kidney disease" (AKD), if criteria for AKI stage 1 or greater persisted. The 6-month all-cause mortality was collected.

RESULTS

A total of 144 patients were included in the analysis. AKI occurred in 69 (48%) patients and 26 (18%) required renal replacement therapy. In a multivariate logistic regression analysis, sex, hypertension, cumulative dose of furosemide, fluid balance, and plateau pressure were independently associated with AKI. Mortality at 6 months was 50% in the AKI group and 32% in the non-AKI group (p = 0.03). Among 36 patients who developed AKI and were discharged alive from the hospital, 56% had a full renal recovery after a month, while 14%, 6%, and 14% were classified as having an AKD of stage 0, 2, and 3, respectively.

CONCLUSIONS

In our cohort, AKI was independently associated with multiple variables, including high plateau pressure, suggesting a possible role of PPV on AKI development. Further studies are needed to clarify the role of mechanical ventilation on renal function.

Status epilepticus resulted in rhabdomyolysis-induced AKI associated with hepatotoxicity induced by synergistic carbamazepine and diazepam: A case report

RATIONALE

Rhabdomyolysis is a serious complication of status epilepticus (SE) caused by muscle cell damage and can lead to a life-threatening acute kidney injury (AKI).

PATIENT CONCERNS

A 35-year-old man with a history of seizures treated with 3 different antiepileptic drugs (carbamazepine, lamotrigine, and levetiracetam) presented with SE. The patient received 5 doses of diazepam to control the SE in another hospital and was transferred to our emergency due to AKI.

DIAGNOSES

Laboratory tests corresponded with rhabdomyolysis-induced AKI and disseminated intravascular coagulation. Thereafter, the decrease in renal excretion of both drugs (diazepam and carbamazepine) caused acute liver injury and neurotoxicity. The carbamazepine concentration was 16.39 mcg/mL, which considered in toxic level, despite using the usual dose.

INTERVENTIONS

The patient was treated with hydration and sodium bicarbonate, however; severe AKI mandated a hemodialysis session.

OUTCOMES

The diuresis started to increase, kidney and liver functions improved, and altered mental status reversed.

LESSONS

This case alerts physicians to consider the synergistic drug side effects and interactions, especially when patients present with impaired liver or kidney functions. The reduction in metabolism or excretion of drugs can cause an increase in serum concentrations and induce toxicity, even when the drug intake at the usual dose.

Bone broth ingestion and acute kidney injury following kidney transplant: a role for cystatin C

Measurement of graft dysfunction following kidney transplant through creatinine is well known to be impacted by many different factors. We report here a clinical scenario demonstrating the importance of dual measurement of glomerular filtration rate (GFR) based on creatinine and cystatin C while also examining within-subject variability of both tests.

The relationship between trajectories of renal oxygen saturation and acute kidney injury: a prospective cohort study with a secondary analysis

BACKGROUND

Acute kidney injury (AKI) is a major postoperative consequence, affecting prognosis of older patients. Effective prediction or intervention to predict or prevent the incidence of AKI is currently unavailable.

AIMS

Dynamic changes of renal tissue oxygen saturation (RSO2) during surgery process are understudied and we intended to explore the distinct trajectories and associations with postoperative AKI.

METHODS

This was a secondary analysis including data for older patients who underwent open hepatectomy surgery with informed consent. Latent class mixed models (LCMM) method was conducted to generate trajectories of intraoperative renal tissue RSO2 through different time points. The primary outcome was postoperative 7-day AKI. The univariate and multivariate regression analysis were performed to identify the relationship between distinct trajectories of renal tissue RSO2 and the risk of AKI. Meanwhile, the prediction efficacy of renal tissue RSO2 at different time points was compared to find potential intervention timing.

RESULTS

Postoperative AKI occurred in 14 (15.2%) of 92 patients. There are two distinct renal tissue RSO2 trajectories, with 44.6% generating "high-downwards" trajectory and 55.4% generating "consistently-high" trajectory. Patients with "high-downwards" trajectory had significantly higher risk of postoperative AKI than another group (Unadjusted OR [Odds Ratio] = 3.790, 95% CI [Confidence Interval]: 1.091-13.164, p = 0.036; Adjusted OR = 3.973, 95% CI 1.020-15.478, p = 0.047, respectively). Predictive performance was 71.4% sensitivity and 60.3% specificity for "high-downwards" trajectory of renal tissue RSO2 to identify AKI. Furthermore, the renal tissue RSO2 exhibited the lowest level and the best results in terms of the sensitivity during the hepatic occlusion period, may be considered as a "time of concern".

CONCLUSIONS

Older patients undergoing hepatectomy may show high-downwards trajectory of renal tissue RSO2, indicating a higher risk of AKI, and the lowest level was identified during the hepatic occlusion period. These findings may help to provide potential candidates for future early recognition of deterioration of kidney function and guide interventions.

Merging machine learning and patient preference: a novel tool for risk prediction of percutaneous coronary interventions

BACKGROUND AND AIMS

Predicting personalized risk for adverse events following percutaneous coronary intervention (PCI) remains critical in weighing treatment options, employing risk mitigation strategies, and enhancing shared decision-making. This study aimed to employ machine learning models using pre-procedural variables to accurately predict common post-PCI complications.

METHODS

A group of 66 adults underwent a semiquantitative survey assessing a preferred list of outcomes and model display. The machine learning cohort included 107 793 patients undergoing PCI procedures performed at 48 hospitals in Michigan between 1 April 2018 and 31 December 2021 in the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) registry separated into training and validation cohorts. External validation was conducted in the Cardiac Care Outcomes Assessment Program database of 56 583 procedures in 33 hospitals in Washington.

RESULTS

Overall rate of in-hospital mortality was 1.85% (n = 1999), acute kidney injury 2.51% (n = 2519), new-onset dialysis 0.44% (n = 462), stroke 0.41% (n = 447), major bleeding 0.89% (n = 942), and transfusion 2.41% (n = 2592). The model demonstrated robust discrimination and calibration for mortality {area under the receiver-operating characteristic curve [AUC]: 0.930 [95% confidence interval (CI) 0.920-0.940]}, acute kidney injury [AUC: 0.893 (95% CI 0.883-0.903)], dialysis [AUC: 0.951 (95% CI 0.939-0.964)], stroke [AUC: 0.751 (95%CI 0.714-0.787)], transfusion [AUC: 0.917 (95% CI 0.907-0.925)], and major bleeding [AUC: 0.887 (95% CI 0.870-0.905)]. Similar discrimination was noted in the external validation population. Survey subjects preferred a comprehensive list of individually reported post-procedure outcomes.

CONCLUSIONS

Using common pre-procedural risk factors, the BMC2 machine learning models accurately predict post-PCI outcomes. Utilizing patient feedback, the BMC2 models employ a patient-centred tool to clearly display risks to patients and providers (https://shiny.bmc2.org/pci-prediction/). Enhanced risk prediction prior to PCI could help inform treatment selection and shared decision-making discussions.

Phenotype-specific therapeutic efficacy of ilofotase alfa in patients with sepsis-associated acute kidney injury

BACKGROUND

There is no effective treatment for sepsis-associated acute kidney injury (SA-AKI). Ilofotase alfa (human recombinant alkaline phosphatase) has been shown to exert reno-protective properties, although it remains unclear which patients might be most likely to benefit. We aimed to identify a clinical phenotype associated with ilofotase alfa's therapeutic efficacy.

METHODS

Data from 570 out of 650 patients enrolled in the REVIVAL trial were used in a stepwise machine learning approach. First, clinical variables with increasing or decreasing risk ratios for ilofotase alfa treatment across quartiles for the main secondary endpoint, Major Adverse Kidney Events up to day 90 (MAKE90), were selected. Second, linear regression analysis was used to determine the therapeutic effect size. Finally, the top-15 variables were used in different clustering analyses with consensus assessment.

RESULTS

The optimal clustering model comprised two phenotypes. Phenotype 1 displayed relatively lower disease severity scores, and less pronounced renal and pulmonary dysfunction. Phenotype 2 exhibited higher severity scores and creatinine, with lower eGFR and bicarbonate levels. Compared with placebo treatment, ilofotase alfa significantly reduced MAKE90 events for phenotype 2 patients (54% vs. 68%, p = 0.013), but not for phenotype 1 patients (49% vs. 46%, p = 0.54).

CONCLUSION

We identified a clinical phenotype comprising severely ill patients with underlying kidney disease who benefitted most from ilofotase alfa treatment. This yields insight into the therapeutic potential of this novel treatment in more homogeneous patient groups and could guide patient selection in future trials, showing promise for personalized medicine in SA-AKI and other complex conditions.

Multi-Omics Integrated Analysis of the Protective Effect of EZH2 Inhibition in Mice with Renal Ischemia-Reperfusion Injury

INTRODUCTION

Acute kidney injury (AKI) is a common clinical syndrome associated with high morbidity and mortality. Inhibition of the methyltransferase enhancer of zeste homolog 2 (EZH2) by its inhibitor 3-deazaneplanocin A (3-DZNeP) exerts renal benefits in acute renal ischemia-reperfusion injury (IRI). However, the underlying mechanisms are not completely known. This study aimed to elucidate the pathological mechanism of EZH2 in renal IRI by combination of multi-omics analysis and expression profiling in a public clinical cohort.

METHODS

In this study, C57BL/6 J mice were used to establish the AKI model, which were treated with 3-DZNeP for 24 h. Kidney samples were collected for RNA-seq analysis, which was combined with publicly available EZH2 chromatin immunoprecipitation sequencing (ChIP-seq) data of mouse embryonic stem cell for a joint analysis to identify differentially expressed genes. Several selected differentially expressed genes were verified by quantitative PCR. Finally, single-nucleus sequencing data and expression profiling in public clinical datasets were used to confirm the negative correlation of the selected genes with EZH2 expression.

RESULTS

3-DZNeP treatment significantly improved renal pathology and function in IRI mice. Through RNA-seq analysis combined with EZH2 ChIP-seq database, 162 differentially expressed genes were found, which might be involved in EZH2-mediated pathology in IRI kidneys. Four differential expressed genes (Scd1, Cidea, Ghr, and Kl) related to lipid metabolism or cell growth were selected based on Gene Ontology and Kyoto Encyclopedia of Genes and Genome enrichment analysis, which were validated by quantitative PCR. Data from single-nucleus RNA sequencing revealed the negative correlation of these four genes with Ezh2 expression in different subpopulations of proximal tubular cells in IRI mice in a different pattern. Finally, the negative correlation of these four genes with EZH2 expression was confirmed in patients with AKI in two clinical datasets.

CONCLUSIONS

Our study indicates that Scd1, Cidea, Ghr, and Kl are downstream genes regulated by EZH2 in AKI. Upregulation of EZH2 in AKI inhibits the expression of these four genes in a different population of proximal tubular cells to minimize normal physiological function and promote acute or chronic cell injuries following AKI.

Advances in understanding of dendritic cell in the pathogenesis of acute kidney injury

Acute kidney injury (AKI) is characterized by a rapid decline in renal function and is associated with a high morbidity and mortality rate. At present, the underlying mechanisms of AKI remain incompletely understood. Immune disorder is a prominent feature of AKI, and dendritic cells (DCs) play a pivotal role in orchestrating both innate and adaptive immune responses, including the induction of protective proinflammatory and tolerogenic immune reactions. Emerging evidence suggests that DCs play a critical role in the initiation and development of AKI. This paper aimed to conduct a comprehensive review and analysis of the role of DCs in the progression of AKI and elucidate the underlying molecular mechanism. The ultimate objective was to offer valuable insights and guidance for the treatment of AKI.

The effect of ulinastatin on acute kidney injury in patients undergoing off-pump cardiac bypass surgery

BACKGROUND

Ulinastatin, an anti-inflammatory and antioxidant trypsin inhibitor, has shown potential in mitigating acute kidney injury (AKI) and reducing serum creatinine levels after various surgeries. This retrospective study aimed to evaluate the effects of ulinastatin on AKI in patients undergoing off-pump coronary artery bypass (OPCAB) surgery.

METHODS

We hypothesized that the administration of ulinastatin could prevent AKI in OPCAB. Electrical medical records were reviewed to identify OPCAB patients between January 2015 and June 2020. The utilization of ulinastatin was randomly determined and applied during this period. Acute kidney injury was defined according to the KDIGO guideline, and its incidence was compared between the ulinastatin administration group and the control group. To investigate the effect of ulinastatin on renal function, multivariate logistic regression analysis was used to calculate propensity scores for each group.

RESULTS

A total 454 OPCAB were performed, and after following inclusion and exclusion process, 100 patients were identified in the ulinastatin group and 303 patients in the control group. Using 1:2 propensity score matching, we analyzed 100 and 200 patients in the ulinastatin and control groups. The incidence of AKI was similar between the groups (2.5% for the control group, 2.0% for the ulinastatin group, p > 0.999). However, the serum creatinine value on the first post-operative day were significantly lower in the ulinastatin group compared to the control group (0.774 ± 0.179 mg/dL vs 0.823 ± 0.216 mg/dL, P = 0.040), while no significant differences were observed for the other time points (P > 0.05). The length of ICU stay day was significantly shorter in the ulinastatin group (2.91 ± 2.81 day vs 5.22 ± 7.45 day, respectively, P < 0.001).

CONCLUSIONS

Ulinastatin did not have a significant effect on the incidence of AKI; it demonstrated the ability to reduce post-operative serum creatine levels at first post-operative day and shorten the length of ICU stay.