Trends of acute kidney injury after radical or partial nephrectomy for renal cell carcinoma

Prediction of Postoperative Creatinine Levels by Artificial Intelligence after Partial Nephrectomy

Background and Objectives: Multiple factors are associated with postoperative functional outcomes, such as acute kidney injury (AKI), following partial nephrectomy (PN). The pre-, peri-, and postoperative factors are heavily intertwined and change dynamically, making it difficult to predict postoperative renal function. Therefore, we aimed to build an artificial intelligence (AI) model that utilizes perioperative factors to predict residual renal function and incidence of AKI following PN. Methods and Materials: This retrospective study included 785 patients (training set 706, test set 79) from six tertiary referral centers who underwent open or robotic PN. Forty-four perioperative features were used as inputs to train the AI prediction model. XG-Boost and genetic algorithms were used for the final model selection and to determine feature importance. The primary outcome measure was immediate postoperative serum creatinine (Cr) level. The secondary outcome was the incidence of AKI (estimated glomerular filtration rate (eGFR) < 60 mL/h). The average difference between the true and predicted serum Cr levels was considered the mean absolute error (MAE) and was used as a model evaluation parameter. Results: An AI model for predicting immediate postoperative serum Cr levels was selected from 2000 candidates by providing the lowest MAE (0.03 mg/dL). The model-predicted immediate postoperative serum Cr levels correlated closely with the measured values (R2 = 0.9669). The sensitivity and specificity of the model for predicting AKI were 85.5% and 99.7% in the training set, and 100.0% and 100.0% in the test set, respectively. The limitations of this study included its retrospective design. Conclusions: Our AI model successfully predicted accurate serum Cr levels and the likelihood of AKI. The accuracy of our model suggests that personalized guidelines to optimize multidisciplinary plans involving pre- and postoperative care need to be developed.

Novel Biomarkers for Early Detection of Acute Kidney Injury and Prediction of Long-Term Kidney Function Decline after Partial Nephrectomy

Background: Identifying acute kidney injury (AKI) within few hours of onset is certainly helpful. However, early prediction of a long-term eGFR decline may be an even more important goal. Our aim was to identify and compare serum [creatinine, kineticGFR, cystatin C, neutrophil gelatinase–associated lipocalin (NGAL)] and urinary (NephroCheck, NGAL, proteinuria, albuminuria, acantocytes at urinary sediment) predictors of AKI that might efficiently predict long-term GFR decline after robotic Nephron-Spearing Surgery (rNSS). Methods: Monocentric prospective observational study. Patients scheduled for rNSS for suspected localized Renal Cell Carcinoma from May 2017 to October 2017 were enrolled. Samples were collected preoperatively and postoperatively (timepoints: 4 h, 10 h, 24 h, 48 h), while kidney function was re-assessed up to 24 months. Results: 38 patients were included; 16 (42%) developed clinical AKI. The eGFR decline at 24 months was more pronounced after postoperative AKI (−20.75 vs. −7.20, p < 0.0001). KineticGFR at 4 h (p = 0.008) and NephroCheck at 10 h (p = 0.001) were, at multivariable linear regression analysis, efficient predictors of post-operative AKI and long-term eGFR decline if compared to creatinine (R2 0.33 vs. 0.04). Conclusions: NephroCheck and kineticGFR have emerged as promising noninvasive, accurate, and early biomarkers of postoperative AKI and long-term GFR decline after rNSS. Combining NephroCheck and kineticGFR in clinical practice would allow to identify high risk of postoperative AKI and long-term GFR decline as early as 10 h after surgery.

Comparative risk of acute kidney injury among cancer patients treated with immune checkpoint inhibitors

With the development and introduction of immune checkpoint inhibitors (ICIs) in cancer patients, immune-related side effects have increasingly attracted attention. However, the risks of immune-related renal toxicity are poorly characterized. In this study, we performed a network meta-analysis (NMA) of ICI-related randomized clinical trials (RCTs) to elucidate the comparative risk of acute kidney injury (AKI) in cancer patients receiving different ICIs. We also sought to identify other factors potentially affecting the risk of AKI. PubMed and EMBASE were searched for peer-reviewed trial reports published between January 2000 and May 2021. Eligible studies were RCTs studying ICIs in cancer patients and reporting AKI data. We performed a frequentist NMA to evaluate the risk ratios for grade 1-5 and grade 3-5 AKI between the treatment groups. We also assessed the absolute incidence of AKI in the ICI-containing arm using traditional direct meta-analysis. Once significant heterogeneity was detected in a traditional direct meta-analysis, multivariable meta-regression analysis was applied to identify factors that significantly affected the absolute incidence of AKI. A total of 85 RCTs were included in this study. In the NMA for the risk of grade 1-5 and 3-5 AKI, ipilimumab showed a significantly higher risk than avelumab and durvalumab, whereas 1 mg/kg nivolumab plus 3 mg/kg ipilimumab (N1I3) showed a significantly higher risk than other groups. In terms of treatment ranking, durvalumab ± low-dose tremelimumab and avelumab were consistently among the top three safest treatments for grade 1-5 or 3-5 AKI, whereas N1I3, ipilimumab and tremelimumab were consistently among the top three treatments with the highest risk for grade 1-5 or 3-5 AKI. Compared with other cancers, renal cell carcinoma and urothelial carcinoma showed a significantly higher risk of AKI. The incidence of AKI was significantly higher with ICI+chemotherapy than with ICI monotherapy. In this NMA involving large-scale up-to-date ICI trials, we demonstrated the comparative safety of existing ICI drugs for grade 1-5 and grade 3-5 AKI. Based on data from the ICI arms of these trials, we also revealed several potential risk factors for immune-related AKI, including tumor type and treatment paradigm.

Evaluation of Renal Function after Partial Nephrectomy and Detection of Clinically Significant Acute Kidney Injury

Background and Objectives: Consequences of partial nephrectomy (PN), intraoperative hypotension (IOH) and postoperative neutrophil to lymphocyte ratio (NLR) may cause postoperative acute kidney injury (AKI) and in long-term-chronic kidney disease (CKD). Our study aimed to identify the AKI incidence after PN, to find clinically significant postoperative AKI and renal dysfunction, and to determine the predictor factors. Materials and Methods: A prospective observational study consisted of 91 patients who received PN with warm ischemia, and estimated preoperative glomerular filtration rate (eGFR) ≥ 60 mL/min and without abnormal albuminuria. Results: 38 (41.8%) patients experienced postoperative AKI. Twenty-one (24.1%) patients had CKD upstage after 1 year follow-up. Sixty-seven percent of CKD upstage patients had AKI 48 h after surgery and 11% after 2 months. All 15 (16.5%) patients with CKD had postoperative AKI. With IOH, OR 1.07, 95% CI 1.03−1.10 and p < 0.001, postoperative NLR after 48 h (OR 1.50, 95% CI 1.19−1.88, p < 0.001) was the major risk factor of AKI. In multivariate logistic regression analysis, the kidney’s resected part volume (OR 1.08, 95% CI 1.03−1.14, p < 0.001) and IOH (OR 1.10, 95% CI 1.04−1.15, p < 0.001) were retained as statistically significant prognostic factors for detecting postoperative renal dysfunction. The independent risk factor for clinically significant postoperative AKI was only IOH (OR, 1.06; p < 0.001). Only AKI with the CKD upstage group has a statistically significant effect (p < 0.0001) on eGFR 6 and 12 months after surgery. Conclusions: The presence of AKI after PN is not rare. IOH and NLR are associated with postoperative AKI. The most important predictive factor of postoperative AKI is an NLR of over 3.5. IOH is an independent risk factor for clinically significant postoperative AKI and together with kidney resected part volume effects postoperative renal dysfunction. Only clinically significant postoperative AKI influences the reduction of postoperative eGFR after 6 and 12 months.

Oncosurgery-Related Acute Kidney Injury

Oncosurgery is a surgical specialty that focuses on the diagnosis, staging, and management of cancer and cancer-related complications. Acute kidney injury is a common and important complication related to oncologic surgery, associated with longer hospital length of stay, greater costs, increased risk of incident or progressive chronic kidney disease (CKD), and higher mortality. The pathogenesis of oncosurgery-related acute kidney injury is multifactorial and determined by different variables, including patient characteristics (comorbidities, volume status, age, pre-existing CKD), specific cancer type or location, surgical procedure involved, as well as intrinsic neuroendocrine and hemodynamic responses to anesthesia and/or surgery. Early nephrology evaluation may be helpful to assist with preservation of kidney function and prevention of further kidney injury.

Treatment of Acute Kidney Injury in Cancer Patients

Acute kidney injury (AKI), either of pre-renal, renal or post-renal origin, is an important complication in cancer patients, resulting in worse prognosis, withdrawal from effective oncological treatments, longer hospitalizations and increased costs. The aim of this article is to provide a literature review of general and cause-specific treatment strategies for AKI, providing a helpful guide for clinical practice. We propose to classify AKI as patient-related, cancer-related and treatment-related in order to optimize therapeutic interventions. In the setting of patient-related causes, proper assessment of hydration status and avoidance of concomitant nephrotoxic medications is key. Cancer-related causes mainly encompass urinary compression/obstruction, direct tumoural kidney involvement and cancer-induced hypercalcaemia. Rapid recognition and specific treatment can potentially restore renal function. Finally, a pre-treatment comprehensive evaluation of risks and benefits of each treatment should always be performed to identify patients at high risk of treatment-related renal damage and allow the implementation of preventive measures without losing the potentialities of the oncological treatment. Considering the complexity of this field, a multidisciplinary approach is necessary with the goal of reducing the incidence of AKI in cancer patients and improving patient outcomes. The overriding research goal in this area is to gather higher quality data from international collaborative studies.

Statin use and association with postoperative estimated glomerular filtration rates in patients undergoing robotic-assisted partial nephrectomy

OBJECTIVE

To evaluate the association between preoperative statin use with changes in estimated glomerular filtration rate (eGFR) following robotic-assisted partial nephrectomy (RAPN).

METHODS

389 consecutive patients undergoing RAPN were evaluated. Associations of preoperative statin use with change in eGFR from pre-RAPN to POD1, 1 month, 6 months, and 12 months after RAPN were evaluated using longitudinal mixed-effects regression models with random patient-specific intercepts and slopes while accounting for imbalance of preoperative patient and tumor characteristics between groups with stabilized inverse propensity score weighting. Post-operative eGFR change from baseline was measured as total change, maintaining eGFR within 10% of baseline, and as going from eGFR > 60 ml/min/1.73m2 to < 60 ml/min/1.73m2.

RESULTS

167 (43.0%) of 389 patients were on statin therapy preoperatively. Statin patients were older (66 vs. 58 years old) and had higher rates of comorbidities including diabetes mellitus (31.7% vs. 14.9%) and hypertension (82.6% vs. 45%). Statin patients tended to have lower preoperative eGFR (mean±SD, 71.1±17.6 vs. 77.4±19.4 ml/min/1.73m2). There was no evidence of an association of preoperative statin use with changes in eGFR at any time point following RAPN (P=0.66).

CONCLUSION

Patients on pre-operative statins undergoing RAPN had lower eGFR preoperatively compared to those not taking those medications. There was no evidence of an association between preoperative statin use and change in post-RAPN eGFR in the immediate post-operative period or at 1 year following surgery.

Immune-related adverse events and kidney function decline in patients with genitourinary cancers treated with immune checkpoint inhibitors

BACKGROUND

In patients with genitourinary cancers, the effect of immune checkpoint inhibitors (ICIs) on kidney function is unknown.

PATIENTS AND METHODS

This is a retrospective cohort study of patients with renal cell carcinoma (RCC) and urothelial carcinoma who received ICIs at two major cancer centers between 2012 and 2018. Cumulative incidence and Fine and Gray subdistribution hazard models were performed to determine predictors of the co-primary outcomes, (1) acute kidney injury (AKI) and (2) sustained estimated glomerular filtration rate (eGFR) loss, defined as a >20% decline in eGFR sustained ≥90 days. We also determined the association between immune-related adverse events (irAE) and adverse kidney outcomes among patients surviving ≥1 year.

RESULTS

637 patients were included; 320 (50%) patients had RCC and 317 (50%) patients had urothelial carcinoma. Half of the cohort had eGFR<60 mL/min/1.73 m² at baseline. irAEs, AKI, and sustained eGFR loss were common, occurring in 33%, 25% and 16%, respectively. Compared to patients with urothelial carcinoma, patients with RCC were more likely to develop irAEs (aHR 1.61, 95% CI 1.20-2.18) and sustained eGFR loss (aHR 1.97, 95% CI 1.24-3.12), but not AKI (aHR 1.53, 95% CI 0.97-2.41). Among patients surviving ≥1 years, experiencing a non-renal irAE was associated with a significantly higher risk of sustained eGFR loss (aHR 1.71, 95% CI 1.14-2.57).

CONCLUSION

AKI and sustained eGFR loss are common in patients with genitourinary cancers receiving ICIs. irAEs may be a novel risk factor for kidney function decline among patients receiving ICIs.

Machine learning-based prediction of acute kidney injury after nephrectomy in patients with renal cell carcinoma

The precise prediction of acute kidney injury (AKI) after nephrectomy for renal cell carcinoma (RCC) is an important issue because of its relationship with subsequent kidney dysfunction and high mortality. Herein we addressed whether machine learning (ML) algorithms could predict postoperative AKI risk better than conventional logistic regression (LR) models. A total of 4104 RCC patients who had undergone unilateral nephrectomy from January 2003 to December 2017 were reviewed. ML models such as support vector machine, random forest, extreme gradient boosting, and light gradient boosting machine (LightGBM) were developed, and their performance based on the area under the receiver operating characteristic curve, accuracy, and F1 score was compared with that of the LR-based scoring model. Postoperative AKI developed in 1167 patients (28.4%). All the ML models had higher performance index values than the LR-based scoring model. Among them, the LightGBM model had the highest value of 0.810 (0.783-0.837). The decision curve analysis demonstrated a greater net benefit of the ML models than the LR-based scoring model over all the ranges of threshold probabilities. The application of ML algorithms improves the predictability of AKI after nephrectomy for RCC, and these models perform better than conventional LR-based models.

Total renal volume and renal function after radical nephrectomy in renal neoplasm

INTRODUCTION

The reduction of renal mass after radical nephrectomy (RN) for renal neoplasm, could be associated with compensatory hypertrophy of the contralateral kidney. The capacity of compensation will determine the renal function (RF) evolution. Measuring of total renal volume (TRV) of the remaining kidney pre and post RN can help assess the RF evolution.

OBJECTIVES

To determine the correlation between TRV pre and post nephrectomy (a year of follow-up) with RF.

MATERIALS AND METHODS

A retrospective cohort study was carried out in 47 patients who had undergone RN from 2014 to 2018, due to renal cell carcinoma (confirmed by histopathology). The TRV was calculated, pre and post (a year of follow-up) RN, using ellipsoid formula equation, which were compared with clinical and analytical data. The results were analyzed by multivariate linear logistic models.

RESULTS

The median age at the time of RN was 70 years old (range, 40-88 years). Most of them were men, 66%. The estimated glomerular filtration rate (eGFR) pre and post nephrectomy was 78 (40-100) and 53.3ml/min/m² (30-90) respectively (p=0.01). The TRV pre and post-nephrectomy was 168.2ml (100.4-257.2) and 187.8ml (115.5-273.1) respectively (p=0.001). The pre-nephrectomy eGFR (β=0.62; p=0.034) and the TRV (β=1.08; p<0.0001) were positively correlated with the post-nephrectomy TRV, while the eGFR at year of follow-up was correlated negatively (β=-1.18; p=0.047).

CONCLUSIONS

The measurement of pre and post nephrectomy TRV can help to predict renal function evolution at a year of follow-up.

Influence of age on gender-related differences in acute kidney injury after minimally invasive radical or partial nephrectomy

BACKGROUND

Female gender is known to be protective against acute kidney injury (AKI) after radical or partial nephrectomy and estrogen is considered a protective factor. If estrogen is a major contributor to the protective effects of female gender against renal injury, these protective effects may be diminished in postmenopausal women. Therefore, this retrospective study investigated the influence of female age on gender-related differences in AKI after minimally invasive radical or partial nephrectomy.

METHODS

Patients who underwent minimally invasive radical (n = 765) or partial (n = 1161) nephrectomy were selected. These patients were stratified by gender and divided into three age categories considered to be pre, peri, and postmenopausal periods in women: ≤ 40 years, 41-59 years, and ≥ 60 years, respectively. Adjusted logistic regression analyses were conducted to identify the risk of AKI according to gender and age.

RESULTS

The incidence of AKI after radical or partial nephrectomy was significantly higher in men as compared to women in all age categories. Women aged ≥ 60 years had a significantly increased risk of AKI as compared to women aged < 60 years in radical nephrectomy, but not in partial nephrectomy. When compared with women aged ≥ 60 years, men aged > 40 years accompanied significantly higher risk of AKI following both radical and partial nephrectomy, even after adjusting confounders. However, men aged ≤ 40 years had a similar risk of AKI after radical nephrectomy, but a significantly higher risk after partial nephrectomy as compared to women aged ≥ 60 years.

CONCLUSION

Male gender was associated with a higher risk of AKI after radical and partial nephrectomy as compared to postmenopausal women. This calls for more thorough preoperative counseling and renal protective strategies in male patients when undergoing radical and partial nephrectomy.

Renal toxicity of targeted therapies for renal cell carcinoma in patients with normal and impaired kidney function

The introduction of novel targeted therapies during the last 2 decades has led to a significant improvement in patients' clinical outcomes with renal cell carcinoma. However, this improvement came at the price of a whole new spectrum of adverse events, including renal toxicity. Systemic treatment of patients with kidney neoplasms who often present with impairment of kidney function, even prior to treatment, poses an increasing diagnostic and therapeutic challenge for clinicians. Common lifestyle-related comorbidities, i.e., hypertension and diabetes, may contribute to further impairment of kidney function. The lack of official guidelines and the exclusion of patients with reduced kidney function from the clinical trials of recently approved drugs complicate the issue even further. Early detection and correct management of renal toxic effects are crucial to preserve kidney function and ensure the optimal administration of life-prolonging therapies. This review presents detailed information on the renal toxicities of three groups of drugs commonly used in renal cell carcinoma treatment: tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors, and immune checkpoint inhibitors. We outline the incidence and underlying mechanisms of renal adverse effects with a focus on patients on renal replacement therapy, as well as present suggestions for their management.

The Nephrologist's Management of Renal Cell Carcinoma After Kidney Surgery

Renal cell carcinoma is associated with chronic kidney disease as well as with common risk factors including hypertension and diabetes mellitus. Localized renal cell carcinoma is treated surgically and in these cases has a favorable prognosis. In particular, in those individuals with small renal masses (≤4 cm), preservation of kidney function should be prioritized. Postoperative chronic kidney disease or end-stage renal disease prevention should include baseline kidney function and risk factor assessment, nontumor renal biopsy, as well as counseling on treatment options to discuss maximizing kidney function preservation. Postnephrectomy prognosis can be determined with repeat laboratory and clinical assessment. Ultimately, early involvement of the nephrologist in a multidisciplinary team including the urology team will enable the reduction of postsurgical kidney disease related morbidity and potentially mortality.

Nephrotoxicity of Anti-Angiogenic Therapies

The use of inhibitors of vascular endothelial growth factor (VEGF)/vascular endothelial growth factor receptor 2 (VEGFR2) signaling for the treatment of cancer has increased over the last decade. This signaling pathway plays a fundamental role in angiogenesis and also in kidney physiology. The emergence of anti-angiogenic therapies has led to adverse nephrotoxic effects, despite improving the outcomes of patients. In this review, we will present the different anti-angiogenic therapies targeting the VEGFR pathway in association with the incidence of renal manifestations during their use. In addition, we will discuss, in detail, the pathophysiological mechanisms of frequent renal diseases such as hypertension, proteinuria, renal dysfunction, and electrolyte disorders. Finally, we will outline the cellular damage described following these therapies.

Total renal volume and renal function after radical nephrectomy in renal neoplasm

INTRODUCTION

The reduction of renal mass after radical nephrectomy (RN) for renal neoplasm, could be associated with compensatory hypertrophy of the contralateral kidney. The capacity of compensation will determine the renal function (RF) evolution. Measuring of total renal volume (TRV) of the remaining kidney pre and post RN can help assess the RF evolution.

OBJECTIVES

To determine the correlation between TRV pre and post nephrectomy (a year of follow-up) with RF.

MATERIALS AND METHODS

A retrospective cohort study was carried out in 47 patients who had undergone RN from 2014 to 2018, due to renal cell carcinoma (confirmed by histopathology). The TRV was calculated, pre and post (a year of follow-up) RN, using ellipsoid formula equation, which were compared with clinical and analytical data. The results were analyzed by multivariate linear logistic models.

RESULTS

The median age at the time of RN was 70 years old (range, 40-88 years). Most of them were men, 66%. The estimated glomerular filtration rate (eGFR) pre and post nephrectomy was 78 (40-100) and 53.3ml/min/ m² (30-90) respectively (P=.01). The TRV pre and post-nephrectomy was 168.2ml (100.4-257.2) and 187.8ml (115.5-273.1) respectively (P=.001). The pre-nephrectomy eGFR (β=0.62; P=.034) and the TRV (β=1.08; P<.0001) were positively correlated with the post-nephrectomy TRV, while the eGFR at year of follow-up was correlated negatively (β=-1.18; P=.047) CONCLUSIONS: The measurement of pre and post nephrectomy TRV can help to predict renal function evolution at a year of follow-up.

Elevated preoperative C-reactive protein is associated with renal functional decline and non-cancer mortality in surgically treated renal cell carcinoma: analysis from the INternational Marker Consortium for Renal Cancer (INMARC)

OBJECTIVE

To investigate association of preoperative C-reactive protein (CRP) and non-cancer mortality (NCM) in a cohort of patients undergoing surgery for localised renal cell carcinoma (RCC).

PATIENTS AND METHODS

Retrospective multicentre analysis of patients surgically treated for clinical Stage 1-2 RCC from 2006 to 2017, excluding all cases of cancer-specific mortality. Descriptive analyses were obtained between the pre-treatment normal-CRP (≤5 mg/L) and elevated-CRP (>5 mg/L) groups. The primary outcome was NCM. The secondary outcomes included progression to de novo chronic kidney disease Stages 3-4 (estimated glomerular filtration rate [eGFR] of <60, <45, and <30 mL/min/1.73 m² ). Multivariable analyses (MVA) were performed to assess for risk factors associated with functional decline and NCM, and Kaplan-Meier analysis was used to obtain survival estimates for outcomes.

RESULTS

A total of 1987 patients who underwent radical or partial nephrectomy were analysed (normal-CRP group, n = 963; elevated-CRP group, n = 1024). Groups were similar in age (59 vs 60 years, P = 0.079). An elevated CRP was more frequent in males (36.8% vs 27.8%, P < 0.001), African-Americans (22.6% vs 2.9%, P < 0.001), and in those with a higher median body mass index (30 vs 25 kg/m² , P < 0.001) and larger median tumour size (4.5 vs 3.3 cm, P < 0.001). On MVA, an elevated CRP was independently associated with development of de novo eGFR of <60 mL/min/1.73 m² (hazard ratio [HR] 1.32, P = 0.015), <45 mL/min/1.73 m² (HR 1.41, P = 0.023) and <30 mL/min/1.73 m² (odds ratio 2.23, P < 0.001). The MVA for factors associated with NCM demonstrated increasing age (HR 1.06, P < 0.001), preoperative elevated CRP (HR 2.18, P < 0.001) and an eGFR of <45 mL/min/1.73 m² (HR 1.16; P = 0.021) as independent risk factors. Kaplan-Meier analysis revealed significantly higher 5-year NCM in the elevated-CRP group vs the normal-CRP group (98% vs 80%, P < 0.001).

CONCLUSIONS

Pre-treatment elevated CRP was independently associated with both progressive renal functional decline and NCM in patients undergoing surgery for Stage 1-2 RCC. Patients with elevated CRP and Stage 1 and 2 RCC may be considered as having indication for nephron-sparing strategies, which may be prioritised if oncologically appropriate.

Development and Validation of a Nomogram Model to Predict Acute Kidney Disease After Nephrectomy in Patients with Renal Cell Carcinoma

Purpose

To develop and validate a nomogram model to predict the occurrence of acute kidney disease (AKD) after nephrectomy.

Patients and Methods

A retrospective cohort including 378 patients with renal cell carcinoma (RCC) who had undergone radical or partial nephrectomy between March 2013 and December 2017 at the First Affiliated Hospital of Zhengzhou University was analyzed. Of these, patients who had undergone surgery in an earlier period of time formed the training cohort (n=265) for nomogram development, and those who had undergone surgery thereafter formed the validation cohort (n=113) to confirm the model's performance. The incidence rate of AKD was measured. Univariate and multivariate logistics regression analysis was used to estimate the independent risk factors associated with AKD. The independent risk factors were incorporated into the nomogram. The accuracy and utility of the nomogram were evaluated by calibration curve and decision curve analysis, respectively.

Results

Overall, AKD occurred in 27.5% and 28.3% of patients in the training and validation cohorts, separately. The final nomogram included surgery approach, Charlson comorbidity index (CCI), and the decrement of eGFR. This model achieved good concordance indexes of 0.78 (95% CI=0.71-0.84) and 0.76 (95% CI=0.67-0.86) in the training and validation cohorts, respectively. The calibration curves and decision curve analysis (DCA) demonstrated the accuracy and the clinical usefulness of the proposed nomogram, separately.

Conclusion

The nomogram accurately predicts AKD after nephrectomy in patients with RCC. The risk for patients' progress into AKD can be determined, which is useful in guiding clinical decisions.

Acute kidney injury in solitary kidney patients after partial nephrectomy: incidence, risk factors and prediction

Background

To analyze the incidence and risk factors of acute kidney injury (AKI) after partial nephrectomy (PN) in patients with solitary kidney, and to build AKI prediction models using logistic regression and machine learning (ML) approaches.

Methods

Clinical data of 87 solitary kidney patients with renal mass who received PN from January 2003 to March 2019 were collected. The diagnosis of AKI was based on KDIGO criteria. Logistic regression analysis and ML method were used to build prediction models.

Results

AKI developed in 52 (59.8%) patients. The logistic regression model had three variables: ischemia time (P=0.003), surgery time (P=0.001) and preoperative fasted blood glucose level (FBG) (P=0.049). The area under curve (AUC) was 0.826, with the specificity and sensitivity of optimal threshold value 82.9% and 69.2%. The ML model had the following variables: ischemia time, surgery time, age, FBG, mean arterial pressure (MAP), colloid, crystalloid, etc. XGBoost model has the best prediction performance. The AUC was 0.749, lower than that of the logistic regression model with no statistical difference (P=0.258), with the specificity and sensitivity 62.9% and 84.6%, respectively.

Conclusions

The incidence of AKI after PN in patients with a solitary kidney was relatively high, it was associated with longer ischemia time, surgery time and higher FBG level, etc. The performance of ML model had no significant difference with logistic regression model. Prospective studies with larger sample sizes are awaited to test and verify our research findings.

Acute Kidney Injury in Patients Receiving Systemic Treatment for Cancer: A Population-Based Cohort Study

BACKGROUND

Patients undergoing treatment for cancer are at increased risk of acute kidney injury (AKI). There are few data on AKI incidence and risk factors in the current era of cancer treatment.

METHODS

We conducted a population-based study of all patients initiating systemic therapy (chemotherapy or targeted agents) for a new cancer diagnosis in Ontario, Canada (2007-2014). The primary outcome was hospitalization with AKI or acute dialysis. We estimated the cumulative incidence of AKI and fitted Fine and Gray models, adjusting for demographics, cancer characteristics, comorbidities, and coprescriptions. We modeled exposure to systemic therapy (the 90-day period following treatments) as a time-varying covariate. We also assessed temporal trends in annual AKI incidence.

RESULTS

We identified 163 071 patients initiating systemic therapy of whom 10 880 experienced AKI. The rate of AKI was 27 per 1000 person-years, with overall cumulative incidence of 9.3% (95% CI = 9.1% to 9.6%). Malignancies with the highest 5-year AKI incidence were myeloma (26.0%, 95% CI = 24.4% to 27.7%), bladder (19.0%, 95% CI = 17.6% to 20.5%), and leukemia (15.4%, 95% CI = 14.3% to 16.5%). Advanced cancer stage, chronic kidney disease, and diabetes were associated with increased risk of AKI (adjusted hazard ratios [aHR] = 1.41, 95% CI = 1.28 to 1.54; 1.80, 95% CI = 1.67 to 1.93; and 1.43, 95% CI = 1.37 to 1.50, respectively). In patients aged 66 years or older with universal drug benefits, diuretic, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker coprescription was associated with higher AKI risk (aHR = 1.20, 95% CI = 1.14 to 1.28; 1.30, 95% CI = 1.23 to 1.38). AKI risk was further accentuated during the 90-day period following systemic therapy (aHR = 2.34, 95% CI = 2.24 to 2.45). The annual incidence of AKI increased from 18 to 52 per 1000 person-years between 2007 and 2014.

CONCLUSION

Cancer-related AKI is common and associated with advanced stage, chronic kidney disease, diabetes, and concomitant receipt of diuretics or angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Risk is heightened in the 90 days after systemic therapy. Preventive strategies are needed to address the increasing burden of AKI in this population.

Acute kidney injury after nephron sparing surgery and microwave ablation: focus on incidence, survival impact and prediction

Purpose: To compare acute kidney injury (AKI) incidence between nephron sparing surgery (NSS) and microwave ablation (MWA) for T1a RCC patients, reveal the effect of AKI on survival prognosis, construct AKI nomogram and use Law of Total Probability for survival probability (SP) prediction.Materials and methods: Patients were studied retrospectively after NSS (n = 1267) or MWA (n = 210) from January 1, 2011 to June 30, 2017. Using one to one Propensity Score Matching (PSM), 158 pairs of patients were identified for the cohort study. AKI incidence, risk factors and impact on survival outcomes were analyzed using Chi-square test, logistic and cox regression analysis. AKI risk and SP were predicted by nomogram and Law of Total Probability. The performance of the nomogram was assessed with respect to its discrimination, calibration, and clinical usefulness.Results: AKI occurred more commonly in NSS (27.85%) cohort, when compared to MWA (17.72%) cohort (p = 0.032), but treatment modality was not independently predictive of AKI occurrence (odds ratio [OR]: 0.598; 95% confidence interval [CI]: 0.282-1.265; p = 0.178). The 5-yr overall survival (OS) was lower in AKI patients (73.5%) compared with non-AKI patients (94.8%; p < 0.001). AKI was an independent risk factor for all-cause mortality in RCC patients (hazard ratio [HR]: 2.820; 95% confidence interval [CI]: 1.110-7.165; p = 0.029). Predictors for both NSS- and MWA-related AKI included tumor diameter, baseline eGFR and CCI score. RENAL score and tumor blood supply can predict AKI after NSS and MWA, respectively. The AKI normograms demonstrated good discrimination, with AUCs >0.86, excellent calibration and net benefits at the decision curve analysis with probabilities ≥5%. SP predicted by Law of Total Probability was comparable to actual OS.Conclusion: AKI was an early indicator for poor overall survival in RCC patients. It can be predicted by several oncological parameters. Nomogram and Law of Total Probability can accurately predict AKI risk and SP.

Development of a risk scoring system for predicting acute kidney injury after minimally invasive partial and radical nephrectomy: a retrospective study

BACKGROUND

Acute kidney injury after partial or radical nephrectomy remains an unsolved problem even when using minimally invasive techniques. We aimed to identify risk factors for acute kidney injury (AKI) after minimally invasive nephrectomy and to develop a clinical risk scoring system.

METHODS

Medical records of 1762 patients who underwent minimally invasive laparoscopic or robot-assisted laparoscopic partial (n = 1009) or radical (n = 753) nephrectomy from December 2005 to November 2018 were reviewed. Candidate risk factors were screened using univariate analysis and ranked using linear discriminant analysis; top ranking factors were incorporated into a multivariate logistic regression model. Then, the final clinical scoring system was created based on the estimated odds ratios.

RESULTS

The incidence of acute kidney injury after partial or radical nephrectomy was 20.3 and 61.6%, respectively. Risk factors incorporated into the scoring system included: size of the parenchymal mass removed (3 < parenchymal mass ≤ 4 cm, 1 point; 4 < parenchymal mass ≤ 6 cm, 3 points; parenchymal mass > 6 cm, 5 points), male sex (2 points), diabetes mellitus (1 point), warm ischemia time ≥ 25 min (1 point), and immediate postoperative neutrophil count ≥ 12,000 µl^-1 (1 point) in patients with partial nephrectomy, and sex (male, 10 points; female, 7 points) in patients with radical nephrectomy. For risk scores of 0-4, 5-6, 7, 8-9, and 10 points, the probabilities of acute kidney injury were approximately 10, 20, 40, 60, and 80%, respectively. The predictive accuracy of the scoring system was 0.827 (95% CI 0.789-0.865).

CONCLUSION

Our risk scoring system could help clinicians identify those at risk of acute kidney injury after minimally invasive partial or radical nephrectomy, thereby optimizing postoperative management.

Impact of the Type of Analgesic Therapy on Postsurgical Complications of Patients with Kidney Cancer Undergoing Nephrectomy

BACKGROUND

The treatment of kidney cancer usually involves surgery, and in some cases systemic therapy. Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used to control postsurgical pain in patients undergoing nephrectomy for renal cancer. Nevertheless, the association between these drugs and adverse postsurgical outcomes, including deterioration of renal function, is not fully established.

METHODS

This retrospective cohort study included patients >18 years old with kidney cancer undergoing nephrectomy between January 2006 and January 2018. The primary endpoint was to determine the impact of postsurgical analgesic therapy (NSAIDs vs. acetaminophen) on renal function and postsurgical complications. This study was approved by our scientific and bioethical committee.

RESULTS

One hundred patients were included in the final analysis. Clear-cell renal-cell carcinoma was the most frequent histologic subtype. Adequate acute pain control was accomplished in 91% of the patients during hospitalization. Twenty percent of the patients presented postsurgical complications. Bleeding-related complications were the most frequent (9%), followed by surgical-site infection (6%) and acute renal injury (6%). The administration of NSAIDs was not related to any postsurgical complication in comparison with the use of acetaminophen (21.3 vs. 17.9%, respectively). The length of hospital stay did not differ between patients treated with NSAIDs and those treated with acetaminophen (the average stay was 4 days for both groups, p = 0.32).

CONCLUSION

The use of NSAIDs was not related to acute kidney injury, postsurgical complications, or prolonged hospital stay in patients with renal cancer undergoing nephrectomy.

Preoperative proteinuria is associated with increased rates of acute kidney injury after partial nephrectomy

Purpose

We investigated the association between preoperative proteinuria and early postoperative renal function after robotic partial nephrectomy (RPN).

Patients and Methods

We retrospectively reviewed 1121 consecutive RPN cases at a single academic center from 2006 to 2016. Patients without pre-existing CKD (eGFR≥60 mL/min/1.73m²) who had a urinalysis within 1-month prior to RPN were included. The cohort was categorized by the presence or absence of preoperative proteinuria (trace or greater (≥1+) urine dipstick), and groups were compared in terms of clinical and functional outcomes. The incidence of acute kidney injury (AKI) was assessed using RIFLE criteria. Univariate and multivariable models were used to identify factors associated with postoperative AKI.

Results

Of 947 patients, 97 (10.5%) had preoperative proteinuria. Characteristics associated with preoperative proteinuria included non-white race (p<0.01), preoperative diabetes (p<0.01) and hypertension (HTN) (p<0.01), higher ASA (p<0.01), higher BMI (p<0.01), and higher Charlson score (p<0.01). The incidence of AKI was higher in patients with preoperative proteinuria (10.3% vs. 4.6%, p=0.01). The median eGFR preservation measured within one month after surgery was lower (83.6% vs. 91%, p=0.04) in those with proteinuria; however, there were no significant differences by 3 months after surgery or last follow-up visit. Independent predictors of AKI were high BMI (p<0.01), longer ischemia time (p<0.01), and preoperative proteinuria (p=0.04).

Conclusion

Preoperative proteinuria by urine dipstick is an independent predictor of postoperative AKI after RPN. This test may be used to identify patients, especially those without overt CKD, who are at increased risk for developing AKI after RPN.

General Anesthetic Agents and Renal Function after Nephrectomy

The association between the choice of general anesthetic agents and the risk of acute kidney injury (AKI) and long-term renal dysfunction after nephrectomy has not yet been evaluated. We reviewed 1087 cases of partial or radical nephrectomy. The incidence of postoperative AKI, new-onset chronic kidney disease (CKD) and CKD upstaging were compared between general anesthetic agent groups (propofol, sevoflurane, and desflurane). Four different propensity score analyses were performed to minimize confounding for each pair of comparison (propofol vs. sevoflurane; propofol vs. desflurane; sevoflurane vs. desflurane; propofol vs. volatile agents). Study outcomes were compared before and after matching. Kaplan-Meier survival curve analysis was performed to compare renal survival determined by the development of new-onset CKD between groups up to 36 months after nephrectomy. Propofol was associated with a lower incidence of AKI (propofol 23.2% vs. sevoflurane 39.5%, p = 0.004; vs. propofol 21.0% vs. desflurane 34.3%, p = 0.031), a lower incidence of CKD upstaging (propofol 27.2% vs. sevoflurane 58.4%, p < 0.001; propofol 32.4% vs. desflurane 48.6%, p = 0.017) and better three-year renal survival after nephrectomy compared to sevoflurane or desflurane group (Log-rank test propofol vs. sevoflurane p < 0.001; vs. desflurane p = 0.015) after matching. Propofol was also associated with a lower incidence of new-onset CKD after nephrectomy compared to sevoflurane after matching (p < 0.001). There were no significant differences between sevoflurane and desflurane. However, subgroup analysis of partial nephrectomy showed a significant difference only in CKD upstaging. In conclusion, propofol, compared to volatile agents, could be a better general anesthetic agent for nephrectomy to attenuate postoperative renal dysfunction. However, limitations of the retrospective study design and inconsistent results of the subgroup analysis preclude firm conclusions.

Effect of Diabetes Mellitus on Acute Kidney Injury after Minimally Invasive Partial Nephrectomy: A Case-Matched Retrospective Analysis

Postoperative acute kidney injury (AKI) is still a concern in partial nephrectomy (PN), even with the development of minimally invasive technique. We aimed to compare AKI incidence between patients with and without diabetes mellitus (DM) and to determine the predictive factors for postoperative AKI. This case-matched retrospective study included 884 patients with preoperative creatinine levels ≤1.4 mg/dL who underwent laparoscopic or robot-assisted laparoscopic PN between December 2005 and May 2018. Propensity score matching was employed to match patients with and without DM in a 1:3 ratio (101 and 303 patients, respectively). Of 884 patients, 20.4% had postoperative AKI. After propensity score matching, the incidence of postoperative AKI in DM and non-DM patients was 30.7% and 14.9%, respectively (P < 0.001). In multivariate analysis, male sex and warm ischemia time (WIT) >25 min were significantly associated with postoperative AKI in patients with and without DM. In patients with DM, hemoglobin A1c (HbA1c) >7% was a predictive factor for AKI, odds ratio (OR) = 4.59 (95% CI, 1.47⁻14.36). In conclusion, DM increased the risk of AKI after minimally invasive PN; male sex, longer WIT, and elevated HbA1c were independent risk factors for AKI in patients with DM.

Evaluation of Urinary Renal Biomarkers for Early Prediction of Acute Kidney Injury Following Partial Nephrectomy: A Feasibility Study

BACKGROUND

Partial nephrectomy (PN) is the gold standard for the treatment of small renal masses. Urinary biomarkers (UBMs) may serve as early indicators of acute kidney injury (AKI) following PN.

OBJECTIVE

To evaluate the timing, specificity, and sensitivity of several candidate UBMs after PN to determine the most promising UBMs in this setting. We hypothesize that some UBMs will have utility as early markers of AKI.

DESIGN, SETTING, AND PARTICIPANTS

Twenty-two patients undergoing on-clamp robotic or open PN underwent paired urine collection via ureteral catheterization of the affected kidney and Foley catheterization for the unaffected kidney obtained preoperatively, after anesthesia, and at several points in time after renovascular occlusion.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Measured UBMs included albumin, α-glutathione S-transferase, B2M, calbindin, clusterin, cystatin C, epidermal growth hormone, kidney injury molecule 1, neutrophil gelatinase-associated lipocalin, osteoactivin, osteopontin, total protein, trefoil factor 3, uromodulin, and vascular endothelial growth factor.

RESULTS AND LIMITATIONS

The largest fold changes in UBM levels were observed between the baseline values and just prior to vascular occlusion (time "0"). Albumin, clusterin, and calbindin were among the most consistently and significantly increased UBMs. After vascular occlusion and subsequent reperfusion, some UBMs, most notably albumin, calbindin, and total protein, continued to increase in the affected kidney, peaking at 60-90min, followed by decrease to time "0" measurements after 1 d and to baseline levels 14-42 d after surgery. No striking association of UBMs with parameters such as duration of surgery, ischemia time, and tumor complexity was observed.

CONCLUSIONS

The most significant UBM increases were observed when comparing samples obtained at preoperative visit and after anesthesia, but before clamp time. Albumin, clusterin, and calbindin were the most consistently and significantly altered UBMs; further investigation will be necessary to determine whether UBMs can identify AKI earlier in nephrectomy patients.

PATIENT SUMMARY

Factors (biomarkers) measured in the blood or urine can indicate the presence and amount of kidney injury. We evaluated 15 different biomarkers at several points in time prior to, during, and after surgery for kidney cancer. We found that three of these biomarkers were most consistently elevated in patients undergoing partial nephrectomy. Interestingly, the largest increases were observed when comparing samples obtained prior to surgery with those obtained just after anesthesia.

Progression to chronic kidney disease in patients undergoing nephrectomy for small renal masses: a price to pay for a therapeutic success?

Nephrectomy, which constitutes a gold-standard procedure for the treatment of renal-cell carcinoma (RCC), has been widely discussed in the past decade as a significant risk factor of the development of chronic kidney disease (CKD). RCC is the third most common genitourinary cancer in the United States, with an estimated more than 65,000 new cases and 14,970 deaths. The aim of this review was to precisely and comprehensively summarize the status of current knowledge in CKD risk factors after nephrectomy, the advantages of minimally invasive vs. radical nephrectomy, post-nephrectomy biomarkers of CKD, ways of post-operative CKD prevention and, therefore, better understand why various aspects of CKD after nephrectomy. The majority of current studies indicated a better long-term kidney function preservation in patients undergoing partial nephrectomy in comparison to those after radical nephrectomy. Furthermore, a nephron-sparing surgery should be a preferred first-line procedure among young patients with small renal masses. As partial nephrectomy is followed by a greater risk of adverse outcomes relative to radical nephrectomy, a potential survival benefit should always be considered especially in the elderly or patients with comorbidities.

Perioperative Statin Use and Acute Kidney Injury in Patients Undergoing Partial Nephrectomy

BACKGROUND

Statin use is widespread among the general population. Data suggest a potentially beneficial effect of statin therapy on renal function following surgery. The impact of statins on post-partial nephrectomy (PN) renal function is unknown. We hypothesized that perioperative statin use may be associated with reduced rates of acute kidney injury (AKI) in patients undergoing PN.

OBJECTIVES

To evaluate the effect of perioperative statin use on AKI rates in patients undergoing PN.

MATERIALS & METHODS

1,056 patients undergoing PN were identified from a prospectively-maintained institutional renal mass database. Exclusion criteria included lack of preoperative serum creatinine (Cr), concurrent surgeries, and those with baseline Cr <0.4. The binary outcome was AKI, defined using modified Kidney Disease Improving Global Outcomes (KDIGO) criteria. Chi-Square and Cochran-Armitage trend tests were used to evaluate the strength of associations. A multivariate logistic regression model was used to determine predictors of AKI.

RESULTS

Statin use was reported by n = 346 (32.8%) patients at the time of surgery. Univariate analysis demonstrated that statin use was associated with an increased risk of AKI following PN (OR 1.38, CI 1.01-1.88, p = 0.04). On multivariate analysis, statin use was no longer associated with AKI following PN (OR 1.09, CI 0.76-1.56, p = 0.65). Gender, BMI, comorbidity index, hypertension, surgical approach, ischemia temperature/time, and nephrometry "R" score were all independently associated with AKI.

CONCLUSIONS

Perioperative statin use at the time of PN was not associated with rates of post-operative AKI. Prospective studies are needed to elucidate the effects of statins on functional outcomes following PN.

Factors associated with acutely elevated serum creatinine following radical tumour nephrectomy: the Correlates of Kidney Dysfunction-Tumour Nephrectomy Database study

BACKGROUND

To identify factors associated with acutely elevated serum creatinine (SCr) within 7 days of radical tumour nephrectomy.

METHODS

The study population consisted of 130 consecutive patients managed for renal tumours. The primary outcome was acute kidney injury (AKI) (defined as SCr increase ≥50% above baseline), assessed using multivariable logistic regression analysis. The secondary outcome was SCr percentage increase, assessed using multivariable linear regression analysis.

RESULTS

Following nephrectomy, the mean percentage increase in SCr in the first week was 55%±29%, and 77 (59%) patients experienced AKI. Independent predictors of AKI post-nephrectomy were male gender [adjusted odds ratio (OR): 2.67; 95% confidence interval (95% CI): 1.01, 6.93], urine albumin-creatinine ratio (OR: 0.66; 95% CI: 0.47, 0.91), preoperative estimated glomerular filtration rate (eGFR) (OR: 1.03; 95% CI: 1.00, 1.05), laparoscopic nephrectomy (OR: 3.02; 95% CI: 1.00, 9.12), and non-clear cell renal cell carcinoma (RCC) (OR: 2.93; 95% CI: 1.04, 8.29). Independent predictors of a SCr increase were male gender (β: 12.0; 95% CI: 2.69, 21.3), urine albumin-creatinine ratio (β: -3.36; 95% CI: -6.55, -0.16), preoperative eGFR (β: 0.38; 95% CI: 0.10, 0.66), laparoscopic nephrectomy (β: 12.7; 95% CI: 1.05, 24.3) and obesity (β: 9.94, 95% CI: 0.61, 19.3).

CONCLUSIONS

Male gender, albuminuria, eGFR and laparoscopic nephrectomy independently associated with acutely elevated serum creatinine following radical tumour nephrectomy.