Accuracy of Urinary Neutrophil Gelatinase-Associated Lipocalin in Quantifying Acute Kidney Injury after Partial Nephrectomy in Patients with Normal Contralateral Kidney

The evaluation of acute kidney injury due to ischemia by urinary neutrophil gelatinase-induced lipocalin (uNGAL) measurement in patients who underwent partial nephrectomy

PURPOSE

To investigate the role of urinary neutrophil gelatinase-induced lipocalin (uNGAL) measurement in the early diagnosis of acute kidney injury that may occur after intraoperative ischemia in patients undergoing partial nephrectomy (PN).

METHODS

This prospective study included 86 patients who underwent open laparoscopic or robotic partial nephrectomy between May 2017 and May 2019. During the surgery, whether the patients had ischemia or not, type of vascular clamping and the ischemia time were noted. The definition of acute kidney injury (AKI) was classified according to Acute Kidney Injury Network (AKIN) criteria. Urine samples were collected preoperatively and 3 h after renal pedicle clamp removal and uNGAL was measured.

RESULTS

AKI was recorded in 34 (39.5%) of 86 patients after PN. Of the 34 patients, 26 (76.4%) had level 1 and 8 (23.6%) had level 2 AKI. uNGAL levels increased significantly as an early reflection of AKI in patients who underwent intraoperative total or renal artery clamping (p = 0.024). There was no significant postoperative increase in uNGAL in the non-ischemic group (p = 0.163). uNGAL expression was detected well before serum creatinine increase. Patients with AKI after PN had higher uNGAL expression (p = 0.008) However, there was no correlation between the level of AKI and uNGAL expression (r = 0.201, p = 0.066).

CONCLUSION

Ischemic acute kidney injury after nephron-sparing surgery can be detected early by uNGAL measurement. In future studies comparing outcomes of different surgical techniques on renal functions after PN, uNGAL levels may be used.

Neutrophil Gelatinase-associated Lipocalin Significantly Correlates with Ischemic Damage in Patients Undergoing Laparoscopic Partial Nephrectomy

Background

Laparoscopic partial nephrectomy, which minimizes renal function loss due to its nephron sparing nature, has become a standard technique among many experienced centers worldwide for surgical treatment of localized kidney tumors. Although partial nephrectomy will remain the gold standard, we need to improve perioperative management and surgical method to prevent postoperative acute kidney injury.

Aims

To demonstrate the frequency of the development of postoperative acute kidney injury following laparoscopic partial nephrectomy in patients with healthy contralateral kidney and determine the early predictive effects of serum neutrophil gelatinase-associated lipocalin on ischemia-reperfusion injury and its association with warm ischemia time.

Study Design

Cross-sectional study.

Methods

Eighty patients were included. We analyzed tumor size, operating time, duration of anesthesia, and warm ischemia time. Serum samples were obtained for measurement of serum creatinine, estimated glomerular filtration rate, and neutrophil gelatinase-associated lipocalin level preoperatively, at the postoperative 2^nd hour, and on postoperative days 1 and 2. We used receiver operating characteristic curve for determining the cut-off point of neutrophil gelatinase-associated lipocalin to detect postoperative acute kidney injury. Correlation analysis was performed using Spearman’s test.

Results

Twenty-seven patients developed acute kidney injury on postoperative day 2, and the neutrophil gelatinase-associated lipocalin level increased significantly at the postoperative 2^nd hour in the acute kidney injury group (p=0.048). For a cut-off of 129.375 ng/mL neutrophil gelatinase-associated lipocalin, the test showed 70.0% sensitivity and 68.3% specificity for the detection of acute kidney injury at the postoperative 2^nd hour. For a cut-off of 184.300 ng/mL neutrophil gelatinase-associated lipocalin, the test exhibited 73.3% sensitivity and 63.3% specificity for the detection of acute kidney injury on postoperative day 1. A significant correlation was found between warm ischemia time and neutrophil gelatinase-associated lipocalin level at the postoperative 2^nd hour (r=0.398, p=0.003). The creatinine values were significantly higher and the estimated glomerular filtration rates were significantly lower on postoperative days 1 and 2 in the acute kidney injury group compared with those in the non-acute kidney injury group (p<0.001).

Conclusion

The neutrophil gelatinase-associated lipocalin may be used as an alternative biomarker to serum creatinine in differentiation of ischemic damage in patients undergoing laparoscopic partial nephrectomy.

Urinary versus plasma neutrophil gelatinase-associated lipocalin (NGAL) as a predictor of mortality for acute kidney injury in intensive care unit patients

OBJECTIVE

To examine urinary and plasma neutrophil gelatinase-associated lipocalin (NGAL) levels in predicting ICU mortality.

DESIGN

Prospective observational.

SETTING

University Critical Care setting.

PARTICIPANTS

50 patients with acute kidney injury (AKI).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Serial urinary and plasma concentrations of NGAL were measured. Twenty-five patients had early progression (EP) and 25 patients had early improvement (EI) of AKI. Plasma concentrations of NGAL in the EP group (N=25) were significantly higher than those in the EI group (129 [IQR; 20] vs. 111 [IQR; 32] ng/mL; P=0.009), while urine NGAL levels on admission were similar in both groups (61 [IQR; 20] vs. 65 [IQR; 20] ng/mL; P=0.767). Plasma NGAL concentrations rapidly decreased to 87 [32] ng/mL in the EI group (P<0.001) and while it remained elevated in the EP group (138 [21] ng/mL). Within 28-days, 50% of the patients died in the EP group, whereas no patient died in the EI group (P<0.001). Plasma NGAL was a fair predictor for progression of AKI (AUC; 0.719±0.063; P=0.006). 48-hour changes in plasma NGAL levels predicted death within 28-days of ICU admission (AUC; 0.874±0.048; P<0.001).

CONCLUSION

Early progression of AKI was associated with more death within 28 and 90days. While one time measurement of plasma NGAL levels at the time ICU admission may represent the kidney health status in critical care settings, it does not reliably predict mortality. On the other hand, changes in plasma NGAL within 48h of admission improve the value of this biomarker in predicting ICU mortality.

Ischemia Techniques in Nephron-sparing Surgery: A Systematic Review and Meta-Analysis of Surgical, Oncological, and Functional Outcomes

CONTEXT

The optimal ischemia technique at partial nephrectomy (PN) for renal masses is yet to be determined.

OBJECTIVE

To summarize and analyze the current evidence about surgical, oncological, and functional outcomes after different ischemia techniques (cold, warm, and zero ischemia) at PN.

EVIDENCE ACQUISITION

A computerized systematic literature search was performed by using PubMed (MEDLINE) and Science Direct. Identification and selection of the studies were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria. Outcomes of interest were estimated blood loss (EBL), overall complications, positive surgical margins, local tumor recurrence, and renal function preservation. Meta-analysis and forest-plot diagrams were performed. Overall pooled estimates, together with 95% confidence intervals (CIs), of the incidence of all parameters were obtained using a random effect model (RE-Model) on the log transformed means (MLN), proportion, or standardized mean change, as deemed appropriate.

EVIDENCE SYNTHESIS

One hundred and fifty-six studies were included. No clinically meaningful differences were found in terms of EBL after cold (mean: 215.5; 95% CI: 154.2-276.8m), warm (mean: 201.8; 95% CI: 175.0-228.7ml), or zero (mean: 261.2; 95% CI: 171.0-351.3ml) ischemia technique. Overall, postoperative complications were recorded in 14.1% (95% CI: 6.7-27.4), 11.1% (95% CI: 10.0-12.3), and 9.7% (95% CI: 7.7-12.2) of patients after cold, warm, and zero ischemia (p<0.01), respectively. Positive surgical margins were recorded in 4.8% (95% CI: 1.9-10.9), 4.0% (95% CI: 3.4-4.8), and 5.6% (95% CI: 3.1-9.8) of patients after cold, warm, and zero ischemia (p<0.01), respectively. Local recurrence was recorded in 3.2% (95% CI: 1.9-5.2) and 3.1% (95% CI: 0.7-11.5) of patients after warm and zero ischemia (p<0.01), respectively. The log₂ of estimated glomerular filtration ratio mean changes were-1.37 (95% CI:-3.42 to 0.68),-1.00 (-2.04 to 0.03), and-0.71 (-1.15 to-0.27) ml/min after cold, warm, and zero ischemia, respectively. Low level of evidence, retrospective nature of most of included studies, a high risk of selection bias, and heterogeneity within included studies limited the overall quality of the analysis.

CONCLUSIONS

The effect of ischemia technique at PN is still debatable and subject to confounding by several factors, namely, patients' selection criteria, surgical technique used, and percentage of functional parenchyma spared during surgery. These confounders bias available evidence and were addressed by only a small part of available studies. Unfortunately, the overall quality of literature evidences and the high risk of selection bias limit the possibility of any causal interpretation about the relationship between the ischemia technique used and surgical, oncological, or functional outcomes. Thus, none of the available ischemia technique could be recommended over the other.

PATIENT SUMMARY

The present analysis shows that none of the available ischemia techniques, namely, cold, warm, or zero ischemia, is universally superior to the others, and other factors play a role in the surgical outcome.

The Predictive Role of Biomarkers for the Detection of Acute Kidney Injury After Partial or Radical Nephrectomy: A Systematic Review of the Literature

CONTEXT

Postoperative acute kidney injury (AKI) is a serious complication after kidney surgery, associated with prolonged hospital stay, high morbidity, and mortality. Biomarkers represent a tool of increasing importance to identify renal impairment after partial nephrectomy (PN) or radical nephrectomy (RN) in order to optimize and anticipate the diagnosis of AKI.

OBJECTIVE

The goal of this systematic review is to investigate current insights on the role of biomarkers in predicting renal impairment in patients undergoing PN or RN.

EVIDENCE ACQUISITION

A systematic review was conducted up to November 30, 2017 through PubMed, Scopus, and Embase databases, to identify eligible studies evaluating the role of biomarkers for the prediction of AKI after PN or RN. The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria were applied to select articles.

EVIDENCE SYNTHESIS

According to the study selection criteria, 10 publications were included with a total number of 728 patients. Incidence of AKI was 26.7% (range: 9-58%). Based on the evidence reviewed, serum cystatin C and urinary neutrophil gelatinase-associated lipocalin (NGAL) showed a significant correlation with serum creatinine rise postoperatively, emerging as potential noninvasive and early biomarkers of AKI in patients undergoing renal surgery. In this setting, serum cystatin C and urinary NGAL have preceded the rise in serum creatinine peak from 3 up to 24h, even in case of mild renal damage.

CONCLUSIONS

The literature underlines the potential usefulness of biomarkers such as cystatin C and NGAL as promising and early tools to predict AKI after PN or RN. However, no strong evidence in support of their use is available to date and further investigations are awaited.

PATIENT SUMMARY

We looked at the role of biomarkers in predicting renal injury in patients undergoing partial or radical nephrectomy. Serum cystatin C and urinary neutrophil gelatinase-associated lipocalin have emerged as promising noninvasive, accurate, and early biomarkers.

Clinical significance of serum neutrophil gelatinase-associated lipocalin in the early diagnosis of renal function deterioration after radical nephrectomy

Objectives The standard metrics used to monitor the progression of acute kidney injury (AKI) include markers such as serum creatinine, blood urea nitrogen, and estimated glomerular filtration rate (eGFR). Moreover, neutrophil gelatinase-associated lipocalin (NGAL) expression has been reported to modulate oxidative stress. Methods We aimed to evaluate the usefulness of serum NGAL levels for monitoring renal function after radical nephrectomy (RN). We prospectively collected data from 30 patients who underwent RN. We analyzed serum NGAL and creatinine at 6 time points: preoperative day 1, right after surgery, 6 hours after surgery, postoperative day (POD) 1, POD 3, and POD 5. We compared these measurements according to the eGFR values (classified as chronic kidney disease stage III; CKD III or not) using data obtained 3 months after surgery. Results The mean age was 65.5 years (range, 45–77 years), and the male-to-female ratio was 2:1. At the last follow-up examination, there were 12 patients (40%) with CKD III. Using receiver operating characteristic analysis, we found that serum creatinine on POD 5 (area under the curve [AUC], 0.887; P = 0.000) and NGAL at 6 hours after LRN (AUC, 0.743, P = 0.026) were significant predictors of CKD III. The development of CKD III after LRN was associated with the serum creatinine level on POD 5 and the NGAL at 6 hours after surgery. Conclusions Compared to serum creatinine, serum NGAL enabled earlier prediction of postoperative CKD III. Therefore, serum NGAL measured 6 hours after surgery could be a useful marker for managing patients after RN.

Plasma Neutrophil Gelatinase-associated Lipoprotein in Living Kidney Donors

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker for acute kidney injury. This study was conducted to determine the clinical implications of perioperative plasma NGAL levels for renal function after living donor nephrectomy.

METHODS

Between July 2013 and May 2014, 112 donors underwent live donor nephrectomy at our institution. Donor plasma NGAL levels were measured perioperatively for 6 months. The relationship between perioperative plasma NGAL and recovery of renal function was analyzed. Renal function was estimated with the Modification of Diet in Renal Disease formula.

RESULTS

Mean preoperative NGAL was 62.1 ± 29.5 ng/mL. Plasma NGAL was most elevated 1 week postoperatively (218 ± 95.5 ng/mL), and stabilized after 1 month (122.9 ± 45.3 ng/mL). Preoperative plasma NGAL was not correlated with donor age or preoperative estimated glomerular filtration rates (eGFR), but was negatively correlated with 6-month eGFR (r = -0.458, P < .001). During the observation period, plasma NGAL at 1 week was most correlated with 6-month eGFR (r = -0.554, P < .001). An ROC curve analysis showed that age, preoperative eGFR, and 1-week postoperative plasma NGAL were highly predictive of developing of chronic kidney disease (CKD), defined as eGFR <60 mL/min/1.73 m(2), 6 months postoperatively (AUC = 0.91, P < .001). One-week postoperative plasma NGAL was also independently associated with CKD risk at 6 months (odds ratio: 1.13 for each 10 ng/mL increase, P = .013).

CONCLUSION

Plasma NGAL becomes elevated after kidney donation and can provide information about acute kidney injury during the compensatory hyperfiltration period. Donors with increased perioperative plasma NGAL require close observation because their possibility of developing CKD after donation may be greater.