Risk Factors for Acute Kidney Injury after Coronary Artery Bypass Surgery and Its Detection Using Neutrophil Gelatinase-Associated Lipocalin

Association between carotid intima-media thickness and acute kidney injury following isolated coronary artery bypass surgery

OBJECTIVE

The association between pre-operative carotid intima-media thickness (CIMT) and early postoperative acute kidney injury (AKI) following isolated coronary artery bypass grafting (CABG) was investigated.

METHODS

Data were sought retrospectively of 237 patients (166 male, 71 female; mean age 61.4 ± 8.1 years; range: 32-74), operated on for isolated CABG with cardiopulmonary bypass (CPB) in a single centre between June 2014 and December 2020, with a serum creatinine level < 1.5 mg/dl and normal carotid arteries on Doppler ultrasonography. AKI diagnosis was made according to the Kidney Disease Improving Global Outcomes 2012 Acute Kidney Injury Guideline. Patients were grouped as group 1 with AKI in the early postoperative period (n = 63) and group 2 without AKI ( n = 174). Univariate analyses were done to determine significant clinical factors, and subsequent multiple logistic regression analysis was done to determine independent predictors of AKI.

RESULTS

AKI occurred in 63 (26.6%) patients. Pre-operative CIMT was significantly higher in the AKI group (p = 0.0001). Multivariate logistic regression analysis revealed that elevated pre-operative CIMT ( p = 0.005), C-reactive protein ( p = 0.001), erythrocyte sedimentation rate ( p = 0.005), neutrophil-lymphocyte ratio ( p = 0.0001) and platelet-lymphocyte ratio ( p = 0.0001) increased on the postoperative seventh day. C-reactive protein ( p = 0.04), postoperative first day platelet- lymphocyte ratio ( p = 0.0001), postoperative seventh day erythrocyte sedimentation rate ( p = 0.02) and intubation time ( p = 0.02) were independent predictors of early postoperative AKI following isolated CABG.

CONCLUSIONS

Pre-operative CIMT was found to be an independent predictor of AKI in the early postoperative period of isolated CABG.

Comparative accuracy of biomarkers for the prediction of hospital-acquired acute kidney injury: a systematic review and meta-analysis

Background

Several biomarkers have been proposed to predict the occurrence of acute kidney injury (AKI); however, their efficacy varies between different trials. The aim of this study was to compare the predictive performance of different candidate biomarkers for AKI.

Methods

In this systematic review, we searched PubMed, Medline, Embase, and the Cochrane Library for papers published up to August 15, 2022. We selected all studies of adults (> 18 years) that reported the predictive performance of damage biomarkers (neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver-type fatty acid-binding protein (L-FABP)), inflammatory biomarker (interleukin-18 (IL-18)), and stress biomarker (tissue inhibitor of metalloproteinases-2 × insulin-like growth factor-binding protein-7 (TIMP-2 × IGFBP-7)) for the occurrence of AKI. We performed pairwise meta-analyses to calculate odds ratios (ORs) and 95% confidence intervals (CIs) individually. Hierarchical summary receiver operating characteristic curves (HSROCs) were used to summarize the pooled test performance, and the Grading of Recommendations, Assessment, Development and Evaluations criteria were used to appraise the quality of evidence.

Results

We identified 242 published relevant studies from 1,803 screened abstracts, of which 110 studies with 38,725 patients were included in this meta-analysis. Urinary NGAL/creatinine (diagnostic odds ratio [DOR] 16.2, 95% CI 10.1–25.9), urinary NGAL (DOR 13.8, 95% CI 10.2–18.8), and serum NGAL (DOR 12.6, 95% CI 9.3–17.3) had the best diagnostic accuracy for the risk of AKI. In subgroup analyses, urinary NGAL, urinary NGAL/creatinine, and serum NGAL had better diagnostic accuracy for AKI than urinary IL-18 in non-critically ill patients. However, all of the biomarkers had similar diagnostic accuracy in critically ill patients. In the setting of medical and non-sepsis patients, urinary NGAL had better predictive performance than urinary IL-18, urinary L-FABP, and urinary TIMP-2 × IGFBP-7: 0.3. In the surgical patients, urinary NGAL/creatinine and urinary KIM-1 had the best diagnostic accuracy. The HSROC values of urinary NGAL/creatinine, urinary NGAL, and serum NGAL were 91.4%, 85.2%, and 84.7%, respectively.

Conclusions

Biomarkers containing NGAL had the best predictive accuracy for the occurrence of AKI, regardless of whether or not the values were adjusted by urinary creatinine, and especially in medically treated patients. However, the predictive performance of urinary NGAL was limited in surgical patients, and urinary NGAL/creatinine seemed to be the most accurate biomarkers in these patients. All of the biomarkers had similar predictive performance in critically ill patients.

Trial registrationCRD42020207883, October 06, 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04223-6.

Neutrophil Gelatinase-Associated Lipocalin Measured on Clinical Laboratory Platforms for the Prediction of Acute Kidney Injury and the Associated Need for Dialysis Therapy: A Systematic Review and Meta-analysis

RATIONALE & OBJECTIVE

The usefulness of measures of neutrophil gelatinase-associated lipocalin (NGAL) in urine or plasma obtained on clinical laboratory platforms for predicting acute kidney injury (AKI) and AKI requiring dialysis (AKI-D) has not been fully evaluated. We sought to quantitatively summarize published data to evaluate the value of urinary and plasma NGAL for kidney risk prediction.

STUDY DESIGN

Literature-based meta-analysis and individual-study-data meta-analysis of diagnostic studies following PRISMA-IPD guidelines.

SETTING & STUDY POPULATIONS

Studies of adults investigating AKI, severe AKI, and AKI-D in the setting of cardiac surgery, intensive care, or emergency department care using either urinary or plasma NGAL measured on clinical laboratory platforms.

SELECTION CRITERIA FOR STUDIES

PubMed, Web of Science, Cochrane Library, Scopus, and congress abstracts ever published through February 2020 reporting diagnostic test studies of NGAL measured on clinical laboratory platforms to predict AKI.

DATA EXTRACTION

Individual-study-data meta-analysis was accomplished by giving authors data specifications tailored to their studies and requesting standardized patient-level data analysis.

ANALYTICAL APPROACH

Individual-study-data meta-analysis used a bivariate time-to-event model for interval-censored data from which discriminative ability (AUC) was characterized. NGAL cutoff concentrations at 95% sensitivity, 95% specificity, and optimal sensitivity and specificity were also estimated. Models incorporated as confounders the clinical setting and use versus nonuse of urine output as a criterion for AKI. A literature-based meta-analysis was also performed for all published studies including those for which the authors were unable to provide individual-study data analyses.

RESULTS

We included 52 observational studies involving 13,040 patients. We analyzed 30 data sets for the individual-study-data meta-analysis. For AKI, severe AKI, and AKI-D, numbers of events were 837, 304, and 103 for analyses of urinary NGAL, respectively; these values were 705, 271, and 178 for analyses of plasma NGAL. Discriminative performance was similar in both meta-analyses. Individual-study-data meta-analysis AUCs for urinary NGAL were 0.75 (95% CI, 0.73-0.76) and 0.80 (95% CI, 0.79-0.81) for severe AKI and AKI-D, respectively; for plasma NGAL, the corresponding AUCs were 0.80 (95% CI, 0.79-0.81) and 0.86 (95% CI, 0.84-0.86). Cutoff concentrations at 95% specificity for urinary NGAL were>580ng/mL with 27% sensitivity for severe AKI and>589ng/mL with 24% sensitivity for AKI-D. Corresponding cutoffs for plasma NGAL were>364ng/mL with 44% sensitivity and>546ng/mL with 26% sensitivity, respectively.

LIMITATIONS

Practice variability in initiation of dialysis. Imperfect harmonization of data across studies.

CONCLUSIONS

Urinary and plasma NGAL concentrations may identify patients at high risk for AKI in clinical research and practice. The cutoff concentrations reported in this study require prospective evaluation.

Will urinary biomarkers provide a breakthrough in diagnosing cardiac surgery-associated AKI? - A systematic review

Introduction: Acute kidney injury following cardiac surgery is a dreaded complication contributing to early mortality. Diagnosing AKI using serum creatinine usually results in a delay. To combat this, certain kidney damage specific biomarkers were investigated to identify if they can serve as early predictors of cardiac surgery-associated AKI (CSA-AKI). This study systematically reviews three such biomarkers; NGAL, tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) and insulin-like growth factor binding protein-7 (IGFBP7) to identify if they can serve as early predictors of CSA-AKI.Methods: Systematic search was carried out on literature reporting the diagnostic ability of the three biomarkers from databases in accordance with PRISMA guidelines.Results: We found 43 articles reporting urinary-NGAL levels (n = 34 in adults, n = 9 in children) and 10 studies reporting TIMP-2 and IGFBP7 levels among adults. Interestingly, NGAL showed high diagnostic value in predicting AKI in children (seven among nine studies with AUROC > 0.8). The cell cycle arrest biomarkers, namely TIMP-2 and IGFBP7, showed high diagnostic value in predicting AKI in adults (five among ten studies with AUROC > 0.8).Conclusion: In predicting CSA-AKI; the diagnostic value of NGAL is high in the paediatric population while the diagnostic value of TIMP-2 and IGFBP7 is high in adults.

The effect of Ramadan fasting on kidney function in patients with chronic kidney disease

PURPOSE

Because of the increase in globalization, clinicians all over the world are confronted the questions about safety of Ramadan fasting. However, there is no clear information about whether there is an obstacle for fasting patients with chronic disease. Hence, in the present study, we aimed to investigate the effects of Ramadan fasting on kidney and the factors affecting this relationship in patients with chronic kidney disease.

METHODS

This study involving 117 patients [36 females, 81 males; mean age, 60 (46.0-70.0) years] with stage 2-3 chronic kidney and fasting. Patients were evaluated every 10 days for acute kidney injury (AKI) in Ramadan month. And, patients with acute kidney injury and patients without AKI were grouped.

RESULTS

When the patients were evaluated for AKI, we observed that in 27 patients had acute kidney injury. While patients without AKI fasted for more days (p < 0.001), urea levels and frequency of hypertension were higher in the group with AKI (p = 0.019; p = 0.025 respectively). We also performed univariate and multiple binary logistic regression analysis to identify the risk factors of AKI. Hypertension and number of fasting day were found to be predictive of AKI (p = 0.02; p < 0.001 respectively).

CONCLUSIONS

We found a significant relationship between hypertension, the number of fasting days and acute kidney injury. Patients with chronic kidney damage and hypertension should be evaluated more carefully, informed about the importance of hydration after fasting and should be followed frequently for AKI.

Predictors of Postoperative Acute Kidney Injury after Coronary Artery Bypass Graft Surgery

Objective

The aims of this study were to identify the risk factors associated with acute kidney injury (AKI) after isolated surgical revascularization with cardiopulmonary bypass and to develop a model to predict the appearance of postoperative AKI.

Methods

A total of 435 adult patients who underwent primary isolated coronary artery bypass graft (CABG) surgery, from 2012 to 2016, in the Clinic University Hospital of Valladolid (Spain) were enrolled. AKI was defined according to the risk, injury, failure, loss, and end-stage (RIFLE) criteria. Data were collected from hospital electronic medical records. Multiple logistic regression analysis was used to identify risk factors.

Results

The prevalence of AKI was 12.4%. Multivariate analysis identified age (odds ratio [OR], 1.056; 95% confidence interval [CI], 1.016-1.098; P=0.005), hypertension (OR, 3.078; 95% CI, 1.151-8.230; P=0.018), low ejection fraction (EF) (OR, 6.785; 95% CI, 2.080-22.135; P=0.001), estimated glomerular filtration rate (eGFR) (OR, 1.017; 95% CI, 1.005-1.028; P=0.014), EuroSCORE II (OR, 1.049; 95% CI, 1.004-1.096; P=0.033), and no intake of calcium-channel blockers (CCB) (OR, 4.892; 95% CI, 1.496-16.025; P=0.022) as risk factors for AKI. These risk factors were included in a model to predict postoperative AKI with an area under a receiver operating characteristic curve of 0.783±0.036 (95% CI, 0.713-0.854; P<0.0001).

Conclusion

Age, hypertension, low EF, eGFR, EuroSCORE II, and no intake of CCB were independent risk factors for postoperative AKI. These factors provide an easy and accurate model to predict postoperative AKI in patients undergoing cardiac surgery.

Diagnosis of cardiac surgery-associated acute kidney injury from functional to damage biomarkers

PURPOSE OF REVIEW

Acute kidney injury (AKI) occurs in up to 30% after cardiac surgery and is associated with adverse outcome. Currently, cardiac surgery-associated acute kidney injury (CSA-AKI) is diagnosed by Kidney Disease: Improving Global Outcomes criteria based on creatinine and urine output. To detect and treat AKI earlier, various biomarkers have been evaluated. This review addresses the current position of the two damage biomarkers neutrophil gelatinase-associated lipocalin (NGAL) and [TIMP-2] [IGFBP7] in clinical practice.

RECENT FINDINGS

We present an updated review on the use of blood and urinary NGAL in CSA-AKI. NGAL is a good predictor, and performs better in children than adults. There is a large variation in predictive ability, possibly caused by diversity of AKI definitions used, different time of measurement of NGAL, and lack of specificity of NGAL assays.Similarly, there are conflicting data on the predictive ability of urinary [TIMP-2] [IGFBP7] for CSA-AKI.Recently, both for NGAL and for urinary [TIMP-2] [IGFBP7], a set of actions, based on pretest assessment of risk for CSA-AKI and biomarker test results, was developed. These scores should be evaluated in prospective trials.

SUMMARY

NGAL and urinary [TIMP-2] [IGFBP7], in combination with pretest assessment, are promising tools for early detection and treatment in CSA-AKI.

Cardiac surgery related cardio-renal syndrome assessed by conventional and novel biomarkers - under or overestimated diagnosis?

INTRODUCTION

Serum creatinine is a 'gold standard' criterion of recognizing and staging of acute kidney injury (AKI) despite it being a suboptimal, delayed indicator. The interpretation of increased values of biomarkers imposes great difficulty regarding cardiac surgery procedures performed with cardiopulmonary bypass and may lead to under- or overestimated diagnosis. The aim of this study was to evaluate the clinical utility of the sole serum creatinine or urine neutrophil gelatinase-associated lipocalin (NGAL) concentration used for identification of patients with AKI after cardiac surgery.

MATERIAL AND METHODS

A prospective observational study was conducted on a group of 88 adult patients undergoing a coronary artery bypass grafting procedure. Serum creatinine was evaluated on the day of the operation, and 24 and 48 h post-operatively. Urinary NGAL concentration was measured: immediately after and one hour after cardiopulmonary bypass, and 24 h from the beginning of the operation. We assessed features of kidney injury and 30-day and 5-year mortality.

RESULTS

Patients in the AKI group diagnosed with creatinine level and urine output criteria presented more advanced age (p = 0.01), higher body mass index (p = 0.01) and preoperative myocardial infarction (p = 0.02). Elevation of NGAL level was observed in 5 of 13 cases with AKI, based on creatinine criteria and 4 of 75 cases without AKI. Within 5 years after the surgical procedure the recurrence of renal failure was 36% in the AKI group (with perioperative NGAL elevation in 2 cases only).

CONCLUSIONS

In the cardiac surgery patients the diagnosis of AKI based on sole serum creatinine or urine NGAL concentration confirmed transient kidney injury. However, the clinical implications of these findings are insufficient for prediction of clinical outcome.