Post-operative acute kidney injury in patients with renal cell carcinoma is a potent risk factor for new-onset chronic kidney disease after radical nephrectomy

Association of Kidney Cysts With Progressive CKD After Radical Nephrectomy

RATIONALE & OBJECTIVE

Simple kidney cysts, which are common and usually considered of limited clinical relevance, are associated with older age and lower glomerular filtration rate (GFR), but little has been known of their association with progressive chronic kidney disease (CKD).

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

Patients with presurgical computed tomography or magnetic resonance imaging who underwent a radical nephrectomy for a tumor; we reviewed the retained kidney images to characterize parenchymal cysts at least 5mm in diameter according to size and location.

EXPOSURE

Parenchymal cysts at least 5mm in diameter in the retained kidney. Cyst characteristics were correlated with microstructural findings on kidney histology.

OUTCOME

Progressive CKD defined by dialysis, kidney transplantation, a sustained≥40% decline in eGFR for at least 3 months, or an eGFR<10mL/min/1.73m2 that was at least 5mL/min/1.73m2 below the postnephrectomy baseline for at least 3 months.

ANALYTICAL APPROACH

Cox models assessed the risk of progressive CKD. Models adjusted for baseline age, sex, body mass index, hypertension, diabetes, eGFR, proteinuria, and tumor volume. Nonparametric Spearman's correlations were used to examine the association of the number and size of the cysts with clinical characteristics, kidney function, and kidney volumes.

RESULTS

There were 1,195 patients with 50 progressive CKD events over a median 4.4 years of follow-up evaluation. On baseline imaging, 38% had at least 1 cyst, 34% had at least 1 cortical cyst, and 8.7% had at least 1 medullary cyst. A higher number of cysts was associated with progressive CKD and was modestly correlated with larger nephrons and more nephrosclerosis on kidney histology. The number of medullary cysts was more strongly associated with progressive CKD than the number of cortical cysts.

LIMITATIONS

Patients who undergo a radical nephrectomy may differ from the general population. A radical nephrectomy may accelerate the risk of progressive CKD. Genetic testing was not performed.

CONCLUSIONS

Cysts in the kidney, particularly the medulla, should be further examined as a potentially useful imaging biomarker of progressive CKD beyond the current clinical evaluation of kidney function and common CKD risk factors.

PLAIN-LANGUAGE SUMMARY

Kidney cysts are common and often are considered of limited clinical relevance despite being associated with lower glomerular filtration rate. We studied a large cohort of patients who had a kidney removed due to a tumor to determine whether cysts in the retained kidney were associated with kidney health in the future. We found that more cysts in the kidney and, in particular, cysts in the deepest tissue of the kidney (the medulla) were associated with progressive kidney disease, including kidney failure where dialysis or a kidney transplantation is needed. Patients with cysts in the kidney medulla may benefit from closer monitoring.

Association of Elevated C-Reactive Protein with Worsened Outcomes in Different Histologies of Renal Cortical Tumors: Analysis of the INMARC Registry

BACKGROUND

To evaluate relationship between histological subtypes of renal cell carcinoma (RCC) and preoperative c-reactive protein (CRP).

PATIENTS AND METHODS

We queried the International Marker Consortium for Renal Cancer database for patients affected by RCC. Patients were classified according to their histology: benign tumors, clear cell (cc) RCC, chromophobe (ch) RCC, papillary (p) RCC, and variant histology (vh) RCC; and according to CRP (mg/L): low CRP ≤5 and high CRP >5. Primary outcome was all-cause mortality (ACM). Secondary outcomes were cancer-specific mortality (CSM), recurrence and association between CRP and histology. Multivariable analysis (MVA) via Cox regression and multivariable logistic regression were fitted to elucidate predictors of outcomes.

RESULTS

Total 3902 patients (high CRP n = 1266) were analyzed; median follow up 51 (IQR 20-91) months. On MVA elevated CRP was an independent risk factor associated with increased risk of ACM in benign tumors (HR 5.98, P < .001), ccRCC (HR 2.69, P < .001), chRCC (HR 3.99, P < .001), pRCC (HR 1.76, P = .009) and vhRCC (HR 2.97, P =.007). MVA for CSM showed CRP as risk factor in ccRCC (HR 2.77, P < .001), chRCC (HR 6.16, P = .003) and pRCC (HR 2.29, P = .011), while in vhRCC was not (P = .27). MVA for recurrence reported CRP as risk factor for ccRCC (HR 1.30, P = .013), while in chRCC (P = .33), pRCC (P = .34) and vhRCC (P = .52) was not. On multivariable logistic regression CRP was a predictor of pRCC (OR 1.003, P = .002), while decreasing CRP was associated with benign tumors (OR 0.994, P = .048).

CONCLUSION

Elevated CRP was a robust predictor of worsened ACM in all renal cortical neoplasms. While most frequently observed in pRCC patients, elevated CRP was independently associated with worsened CSM in non-vhRCC. Conversely, elevated CRP was least likely to be noted in benign tumors, and elevation in this subgroup of patients should prompt further consideration for surveillance given increased risk of ACM. Further investigation is requisite.

Trends and predictors of changes in renal function after radical nephrectomy for renal tumours

BACKGROUND

Chronic kidney disease (CKD) is a common postoperative complication in patients who undergo radical nephrectomy for renal tumours. However, the factors influencing long-term renal function require further investigation.

OBJECTIVE

This study was designed to investigate the trends in renal function changes and risk factors for renal function deterioration in renal tumour patients after radical nephrectomy.

METHODS

We monitored changes in renal function before and after surgery for 3 years. The progression of renal function was determined by the progression and degradation of CKD stages. Univariate and multivariate logistic regression analyses were used to analyse the causes of renal function progression.

RESULTS

We analysed the data of 329 patients with renal tumours who underwent radical nephrectomies between January 2013 and December 2018. In this study, 43.7% of patients had postoperative acute kidney injury (AKI), and 48.3% had CKD at advanced stages. Further research revealed that patients' renal function stabilized 3 months after surgery. Additionally, renal function changes during these 3 months have a substantial impact on the progression of long-term renal function changes in patients.

CONCLUSION

AKI may be an indicator of short-term postoperative changes in renal function. Renal function tests should be performed in patients with AKI after radical nephrectomy to monitor the progression of functional impairment, particularly within the first 3 months after radical nephrectomy.

Association Between Kidney Function and Outcomes Following Immune Checkpoint Inhibitor-Based Combination Therapy in Patients With Advanced Renal Cell Carcinoma

BACKGROUND

It remains unclear whether kidney function affects outcomes following immune checkpoint inhibitor (ICI)-based combination therapy for advanced renal cell carcinoma (RCC).

METHODS

We retrospectively evaluated data of 167 patients with advanced RCC, including 98 who received ICI dual combination therapy (ie, immunotherapy [IO]-IO) and 69 who received ICI combined with tyrosine kinase inhibitor (TKI) (ie, IO-TKI). In each regimen, treatment profiles were assessed according to the grade of chronic kidney disease (CKD) as defined by the KDIGO 2012 criteria.

RESULTS

Of the 98 patients who received IO-IO, 31 (32%), 30 (31%), 15 (15%), and 22 (22%) had CKD G1/2, G3a, G3b, and G4/5, respectively. Of the 69 patients who received IO-TKI, 18 (26%), 25 (36%), and 26 (38%) had G1/2, G3a, and G3b/4/5, respectively. Regarding efficacy, progression-free survival, overall survival, or objective response rate was not different according to the CKD grade in both treatment groups (P > .05). Regarding safety, the rate of adverse events, treatment interruption, or corticosteroid administration was not different according to the CKD grade in the IO-IO group (P > .05), whereas in the IO-TKI group, the incidence of grade ≥ 3 adverse events were significantly higher (P = .0292), and the rates of ICI interruption (P = .0353) and corticosteroid administration (P = .0685) increased, according to the CKD grade.

CONCLUSION

There is a differential safety but comparable efficacy profile between the IO-IO and IO-TKI regimens in patients with CKD. Further prospective studies are required to confirm these findings.

Acute kidney injury as an independent predicting factor for stage 3 or higher chronic kidney disease after nephrectomy

BACKGROUND

The association between postoperative acute kidney injury (AKI) and long-term renal function after nephrectomy has not been fully explored, with accurate prognostic models in which AKI is an independent predicting variable still being absent.

METHODS

We conducted a retrospective study of 528 patients who underwent unilateral radical nephrectomy or partial nephrectomy owing to renal cell carcinoma between January 2013 and December 2016. Postoperative AKI was defined as an absolute increase in serum creatinine level by 0.3 mg/dl or ≥5 0% increase from the preoperative value within 48 hours after surgery. The endpoint was the time to the incident stage 3 or higher chronic kidney disease (defined as eGFR<60 ml/min/1.73m²), or any claim for initiation of dialysis. Cox proportional hazards regression analysis was conducted to construct the final model. Internal validation was performed using 10-fold cross-validation. The model was evaluated in discrimination by Harrell's C-index and area under curve (AUC) values, and calibration by calibration plots.

RESULTS

Five hundred twenty-eight patients were finally enrolled in the study cohort, and the median follow-up period was 38 months. Among 528 admitted patients, 232 (43.9%) developed AKI, and stage 3 or higher CKD occurred in 47 (8.9%) patients during the follow-up time, with 33 in 47 patients (70.2%) having postoperative AKI. AKI was significantly correlated with poor prognosis of renal function (HR = 3.079, P < 0.001). After the adjustment of conventional predictors, AKI was still independently related to kidney function deterioration, and the correlation was influenced by the severity of AKI. Five variables were selected to establish the prognostic model, including age, surgery type, preoperative estimated glomerular filtration rate, preoperative blood urea nitrogen, and postoperative AKI. The model had good discrimination, with the Harrell's C-index of 0.92 (95% CI 0.89-0.95), and AUC values varying from 87.7 to 95.7 at different time points.

CONCLUSIONS

AKI during the perioperative period is an independent predicting factor of stage 3 or higher CKD after nephrectomy.

AKI3-Risk Predictors and Scores in Radical Nephrectomy with High Thrombectomy under Extracorporeal Circulation for Renal Cell Carcinoma with Supradiaphragmatic Inferior Vena Cava/Right Atrial Thrombus: A Single-Centre Retrospective Study

Background and Objectives: The recommended therapeutic management in renal cell carcinoma (RCC) with supradiaphragmatic inferior vena cava/right atrial thrombus (IVC/RA) is surgery. Extracorporeal circulation is required. Acute kidney injury (AKI), a frequent complication after nephrectomy and cardiac surgery is associated with long-term kidney disease. This study aims to identify the risk factors involved in the occurrence of the severe postoperative AKI (AKI3) and to analyse various preoperative validated risk scores from cardiac and noncardiac surgery in predicting this endpoint. Materials and Methods: The medical data of all patients with RCC with supradiaphragmatic IVC/RA thrombus who underwent radical nephrectomy with high thrombectomy, using extracorporeal circulation, between 2004-2018 in the Prof. C. C. Iliescu Emergency Institute for Cardiovascular Diseases, Bucharest, were retrospectively analysed. The patients who died intraoperatively were excluded from the study. The predefined study endpoint was the postoperative AKI3. Preoperative, intraoperative and postoperative data were collected according to the stratification of study population in two subgroups: AKI3-present and AKI3- absent patients. EuroSCORE, EuroSCORE II, Logistic EuroSCORE, NSQIP any-complications and NSQIP serious-complications were analysed. Results: We reviewed 30 patients who underwent this complex surgery between 2004-2018 in our institute. Two patients died intraoperatively. Nine patients (32.14%) presented postoperative AKI3. Age (OR 1.151, CI 95%: 1.009-1.312), preoperative creatinine clearance (OR 1.066, CI 95%: 1.010-1.123) and intraoperative arterial hypotension (OR 13.125, CI 95%: 1.924-89.515) were risk factors for AKI3 (univariable analysis). Intraoperative arterial hypotension emerged as the only independent risk factor in multivariable analysis (OR 11.66, CI 95%: 1.400-97.190). Logistic EuroSCORE (ROC analysis: AUC = 0.813, p = 0.008, CI 95%: 0.633-0.993) best predicted the endpoint. Conclusions: An integrated team effort is essential to avoid intraoperative arterial hypotension, the only independent risk factor of AKI3 in this highly complex surgery. Some risk scores can predict this complication. Further studies are needed.

Pneumoperitoneum and Acute Kidney Injury-An Integrative Clinical Concept Review

An increased intraabdominal pressure, particularly when occurring during periods of hemodynamic instability or fluid overload, is regarded as a major contributor to acute kidney injury (AKI) in intensive care units. During abdominal laparoscopic procedures, intraoperative insufflation pressures up to 15 mmHg are applied, to enable visualization and surgical manipulation but with the potential to compromise net renal perfusion. Despite the widely acknowledged renal arterial autoregulation, net arterial perfusion pressure is known to be narrow, and the effective renal medullary perfusion is disproportionately impacted by venous and lymphatic congestion. At present, the potential risk factors, mitigators and risk-stratification of AKI during surgical pneumoperitoneum formation received relatively limited attention among nephrologists and represent an opportunity to look beyond mere blood pressure and intake-output balances. Careful charting and reporting duration and extent of surgical pneumoperitoneum represents an opportunity for anesthesia teams to better communicate intraoperative factors affecting renal outcomes for the postoperative clinical teams. In this current article, the authors are integrating preclinical data and clinical experience to provide a better understanding to optimize renal perfusion during surgeries. Future studies should carefully consider intrabdominal insufflation pressure as a key variable when assessing outcomes and blood pressure goals in these settings.

Protocol for the Flinders Kidney Health Registry: patient outcomes of kidney cancers and nephrectomies

BACKGROUND

Kidney cancer accounts for 2% of new cancers diagnosed in Australia annually. Partial and radical nephrectomy are the treatment of choice for kidney cancer. Nephrectomy is also performed for living donor kidney transplantation. Nephrectomy is a risk factor for new-onset chronic kidney disease (CKD) or deterioration of pre-existing CKD. Understanding the risk factors for new-onset or deterioration of existing CKD after nephrectomy is important in developing preventive measures to provide better care for these patients. There is also a need to understand the incidence, natural history, management trends, and sequelae of radiofrequency ablation as well as surveillance of small renal cancers or small renal masses (SRMs). Clinical registries are critical in providing excellent patient-centre care and clinical research as well as basic science research. Registries evaluate current practice and guide future practice. The Flinders Kidney Health Registry will provide the key information needed to assess various treatment outcomes of patients with kidney cancer and patients who underwent nephrectomy for other reasons. The registry aims to provide clinical decision makers with longitudinal data on patient outcomes, health systems performance, and the effect of evolving clinical practice. The registry will also provide a platform for large-scale prospective clinical studies and research.

METHODS

Patients above the age of 18 undergoing nephrectomy or radiofrequency ablation for any indication and patients with SRMs will be included in the registry. Demographic, clinical and quality of life data will be collected from hospital information systems and directly from the patient and/or caregiver.

DISCUSSION

The Registry will report a summary of patient characteristics including indication for treatment, clinical risk profiles, surgical and oncological outcomes, the proportion of patients who progress to CKD and end stage kidney disease, quality of life post treatment as well as other relevant outcomes for all patients who have undergone nephrectomy for any indication, ablation or surveillance for SRMs. The registry will record the follow-up practice after nephrectomy and patient on active surveillance, which will help to develop and enhance a best practice protocol. The collected prospective data will provide a platform for ongoing patient-orientated research and improve patient-centred healthcare delivery.

Mediators of Regional Kidney Perfusion during Surgical Pneumo-Peritoneum Creation and the Risk of Acute Kidney Injury—A Review of Basic Physiology

Acute kidney injury (AKI), especially if recurring, represents a risk factor for future chronic kidney disease. In intensive care units, increased intra-abdominal pressure is well-recognized as a significant contributor to AKI. However, the importance of transiently increased intra-abdominal pressures procedures is less commonly appreciated during laparoscopic surgery, the use of which has rapidly increased over the last few decades. Unlike the well-known autoregulation of the renal cortical circulation, medulla perfusion is modulated via partially independent regulatory mechanisms and strongly impacted by changes in venous and lymphatic pressures. In our review paper, we will provide a comprehensive overview of this evolving topic, covering a broad range from basic pathophysiology up to and including current clinical relevance and examples. Key regulators of oxidative stress such as ischemia-reperfusion injury, the activation of inflammatory response and humoral changes interacting with procedural pneumo-peritoneum formation and AKI risk will be recounted. Moreover, we present an in-depth review of the interaction of pneumo-peritoneum formation with general anesthetic agents and animal models of congestive heart failure. A better understanding of the relationship between pneumo-peritoneum formation and renal perfusion will support basic and clinical research, leading to improved clinical care and collaboration among specialists.

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.

Effects of time on differential leucocyte counts and biochemical parameters of ovariohysterectomy, gastrotomy and intestinal resection and anastomosis in Nigerian indigenous dogs

Differential leucocytes counts and some biochemical parameters could be affected over time by surgical procedures leading to kidney failure. Hence this study evaluates the effects of ovariohysterectomy (OVH), gastrotomy (GAT) and intestinal resection and anastomosis (ITR) on differential leucocyte counts and some biochemical parameters in Nigerian dogs. Twelve dogs of both sexes weighing 10.8±0.7 kg were randomly divided into three experimental groups of four each. The dogs were pre-treated with atropine sulphate (0.04 mg/kg), Xylazine (2 mg/kg) and propofol (6 mg/kg) parenterally, for induction and maintenance of anaesthesia. Pentazocine (3 mg/kg) was injected after surgery. Pre and post-surgery blood samples were obtained at 0, 2, 24, 48, 72, 96, 120 and 144 h respectively to determine differentials in leucocyte counts, electrolytes, lactate, blood urea nitrogen (BUN) and serum creatinine. Mathematical formulas were used to calculate plasma creatinine, creatinine clearance, plasma creatinine clearance, creatinine half- life, urine creatinine and urine volume. There were significant increases (p ≤ 0.05) in mean sodium, chloride and bicarbonate concentrations at 2, 24, 48, 72, 96 and 120 h post-surgery in group 1 and 2, while group 3 had significant decreases (p ≤ 0.05) in sodium, chloride and bicarbonate ions. Lactate value decreased significantly (p<0.05) in group 1, and increased in group 2 and 3 respectively.BUN increased significantly (p<0.05) in group 1,2 and 3.However, there were significant increases (p<0.05) in lymphocyte concentrations in group 1 and 3, respectively. Monocytes decreased significantly (p<0.05) after surgery. Conclusion: Xylazine and propofol anaesthetics cause hyperlactatemia which can be detrimental in surgical patients with co-morbidities.

Pre-surgical chronic kidney disease continues to drive outcomes in the modern era of minimally invasive renal surgery, despite advances in technology

PURPOSE

To assess the impact of preoperative chronic kidney disease (CKD) on perioperative morbidity and mortality in a contemporary cohort undergoing renal surgery in an era of increased prevalence of minimally invasive surgery and partial nephrectomy.

METHODS

The National Surgery Quality Improvement Program dataset was queried to identify patients undergoing radical nephrectomy (RN) or partial nephrectomy (PN) between 2010 and 2018. CKD staging was assigned based on creatinine clearance calculated using the Cockcroft-Gault formula. Multivariable logistic regression was performed to assess the effect of preoperative CKD stage on postoperative outcomes, including a composite variable encompassing multiple major complications.

RESULTS

We analyzed 19,545 patients with CKD undergoing renal surgery. CKD stage ≥ 2 predicted an increase in major perioperative complications, OR 1.54 (95% CI 1.46-1.63); p < 0.01. The risk of perioperative morbidity increased linearly with increasing CKD stage. Patients with CKD stage > 2 also demonstrated increased 30-day mortality, OR 1.87 (95% CI 1.26-2.48); p < 0.01. Adjusting for surgery type, CKD staging predicted perioperative mortality in patients undergoing RN only, and perioperative morbidity in RN and PN.

CONCLUSIONS

Here, we demonstrate a statistically significant increase in the risk of major postoperative complications following RN and PN with increasing CKD stage. Amongst patients undergoing RN, we also demonstrate increasing 30-day mortality with increasing CKD stage. Importantly, we highlight the ability of CKD staging to predict major perioperative outcomes with greater magnitude of effect than surgery type alone. Thus, we provide a model for translating CKD staging into operative risk amongst patients undergoing surgery for a renal mass.

Risk of Postoperative Renal Failure in Radical Nephrectomy and Nephroureterectomy: A Validated Risk Prediction Model

INTRODUCTION

The study aimed to construct and validate a risk prediction model for incidence of postoperative renal failure (PORF) following radical nephrectomy and nephroureterectomy.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database years 2005-2014 were used for the derivation cohort. A stepwise multivariate logistic regression analysis was conducted, and the final model was validated with an independent cohort from the ACS-NSQIP database years 2015-2017.

RESULTS

In cohort of 14,519 patients, 296 (2.0%) developed PORF. The final 9-factor model included age, gender, diabetes, hypertension, BMI, preoperative creatinine, hematocrit, platelet count, and surgical approach. Model receiver-operator curve analysis provided a C-statistic of 0.79 (0.77, 0.82; p < 0.001), and overall calibration testing R2 was 0.99. Model performance in the validation cohort provided a C-statistic of 0.79 (0.76, 0.81; p < 0.001).

CONCLUSION

PORF is a known risk factor for chronic kidney disease and cardiovascular morbidity, and is a common occurrence after unilateral kidney removal. The authors propose a robust and validated risk prediction model to aid in identification of high-risk patients and optimization of perioperative care.

The relationships of acute kidney injury duration and severity with long-term functional deterioration following partial nephrectomy

PURPOSE

To evaluate the effect of acute kidney injury (AKI) duration and severity on long-term renal functional outcomes in patients undergoing partial nephrectomy (PN).

METHODS

Altogether 292 consecutive patients undergoing laparoscopic PN from 2010 to 2018 were identified in two medical centers. In addition, the AKI duration {transient AK [≤ 3d] or persistent AKI [> 3d]} was combined with AKI severity (stages) to elucidate their relationships with long-term functional results. Kaplan-Meier (KM) analysis was also used to compare among patients with no AKI, transient AKI, and persistent AKI. Moreover, the Cox-proportional hazards regression model was utilized to assess the risk factors for renal function deterioration.

RESULTS

Altogether 67 patients (22.9%) experienced postoperative AKI. 75% eGFR preserve rate during the follow-up was compared among patients with no AKI, transient AKI and persistent AKI using KM analysis and log-rank test, which revealed significant difference. After adjusting for age and warm ischemia time by multivariate model proportional hazards analysis, AKI duration and severity were identified as the risk factors (Stage 1-transient AKI vs. non-AKI: adjusted hazard ratio (HR) 4.361, 95% confidential interval (CI) [2.062-9.233], p < 0.001; stage 1-persistent AKI vs. non-AKI: adjusted HR 6.706, 95% CI [2.405-18.699], p < 0.001; stage 2/3-transient AKI vs. non-AKI: adjusted HR 8.949, 95% CI [1.571-50.963], p = 0.014; stage 2/3-persistent AKI vs. non-AKI: adjusted HR 13.453, 95% CI [11.353-133.798], p = 0.027).

CONCLUSIONS

The AKI duration after PN is an important risk factor for long-term renal functional deterioration. Besides, AKI duration combined with AKI severity can be more comprehensive to understand the role of AKI on ultimately renal function.

TRIAL REGISTRATION

Chinese ClinicalTrials: ChiCTR2000034080.

The effects of acute kidney injury in a multicenter cohort of high-risk surgical patients

BACKGROUND AND OBJECTIVES

Patients who develop post-operative acute kidney injury (AKI) have a poor prognosis, especially when undergoing high-risk surgery. Therefore, the objective of this study was to evaluate the outcome of patients with AKI acquired after non-cardiac surgery and the possible risk factors for this complication.

METHODS

A multicenter, prospective cohort study with patients admitted to intensive care units (ICUs) after non-cardiac surgery was conducted to assess whether they developed AKI. The patients who developed AKI were then compared to non-AKI patients.

RESULTS

A total of 29 ICUs participated, of which 904 high-risk surgical patients were involved in the study. The occurrence of AKI in the post-operative period was 15.8%, and the mortality rate of post-operative AKI patients at 28 days was 27.6%. AKI was strongly associated with 28-day mortality (OR = 2.91; 95% CI 1.51-5.62; p = 0.001), and a higher length of ICU and hospital stay (p < 0.001). Independent factors for the risk of developing AKI were pre-operative anemia (OR = 7.01; 95% CI 1.69-29.07), elective surgery (OR = 0.45; 95% CI 0.21-0.97), SAPS 3 (OR = 1.04; 95% CI 1.02-1.06), post-operative vasopressor use (OR = 2.47; 95% CI 1.34-4.55), post-operative infection (OR = 8.82; 95% CI 2.43-32.05) and the need for reoperation (OR= 7.15; 95% CI 2.58-19.79).

CONCLUSION

AKI was associated with the risk of death in surgical patients and those with anemia before surgery, who had a higher SAPS 3, needed a post-operative vasopressor, or had a post-operative infection or needed reoperation were more likely to develop AKI post-operatively.

Chronic Kidney Disease in Cancer Survivors

As breakthroughs in cancer care are leading to improved long-term outcomes in a subset of advanced cancers, there is a growing population of long-term cancer survivors that are at risk of long-term complications. In this review, we summarize what is known about chronic kidney disease in cancer survivors, focusing on the following high-risk groups: survivors of childhood cancers, stem cell transplant recipients, patients with renal cell carcinoma, patients exposed to cisplatin and other nephrotoxic chemotherapies, and patients receiving immunotherapy for cancer. As new anticancer therapies are developed, more research is needed to understand the long-term risks of kidney function decline and to devise methods to prevent chronic kidney disease.

Renal Cell Cancer and Chronic Kidney Disease

The association between chronic kidney disease (CKD) and renal cell carcinoma (RCC) is bidirectional and multifactorial. Risk factors such as hypertension, diabetes mellitus, obesity, and smoking increase the risk of both CKD and RCC. CKD can lead to RCC via an underlying cystic disease or oxidative stress. RCC can cause CKD because of the tumor itself, surgical reduction of renal mass (either partial or radical nephrectomy), and perioperative acute kidney injury. Medical therapies such as immune checkpoint inhibitors and vascular endothelial growth factor inhibitors can lead to acute kidney injury and resultant CKD. Clinicians need to be aware of the complex, bidirectional interplay between both diseases.

Impact of comorbidities on acute kidney injury and renal function impairment after partial and radical tumor nephrectomy

BACKGROUND

To test for the impact of patient comorbidities and medical risk factors on kidney function after partial (PN) or radical nephrectomy (RN) in renal cell carcinoma (RCC) patients with normal preoperative renal function.

MATERIALS AND METHODS

From January 2011 to December 2014, 195 consecutive RCC patients with a preoperative estimated glomerular filtration rate (eGFR) > 60 ml/min/1.73 m² underwent PN or RN. Stratification was performed according to postoperative acute kidney injury (AKI) vs. no AKI. Moreover, logistic regression models tested for risk factors predicting postoperative AKI and subsequent new-onset chronic kidney disease (eGFR < 60 or < 45 ml/min/1.73 m²).

RESULTS

Of all eligible patients, 127 (65.1%) exhibited AKI. AKI patients underwent more frequently RN (44.9 vs. 13.2% PN) and harbored more often preoperative diabetes (17.3 vs. 5.9% no diabetes), hypertension (46.5 vs. 23.5% no hypertension) and larger median tumor size (4.5 vs. 2.5 cm, all p < 0.05) than non-AKI patients. Moreover, after median follow-up of 14 months, 18.9% of AKI patients exhibited an eGFR < 60 ml/min/1.73 m² vs. 7.4% non-AKI patients (p = 0.01). In multivariable models, hypertension and RN were risk factors for postoperative AKI (both p < 0.01). Age > 60 years and RN as well as preoperative diabetes were risk factors for postoperative eGFR < 60 or < 45 ml/min/1.73 m² (all p < 0.05), respectively.

CONCLUSIONS

Postoperative AKI is a non-negligible event especially after RN that can be further triggered by comorbidities such as diabetes and hypertension. Comorbidities should be considered in clinical decision-making for RCC surgery and patients need to be counseled about the increased risk of consecutive renal function impairment.

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.

Unexpected Outcomes of Renal Function after Radical Nephrectomy: Histology Relevance along with Clinical Aspects

Acute kidney injury (AKI) and chronic kidney disease (CKD) are common events after radical nephrectomy (RN). In this study we aimed to predict AKI and CKD after RN relying on specific histological aspects. We collected data from a cohort of 144 patients who underwent radical nephrectomy. A histopathological review of the healthy part of the removed kidney was performed using an established chronicity score (CS). Logistic regression analyses were performed to predict AKI after RN, while linear regression analysis was adopted for estimated glomerular filtration rate (eGFR) variation at 1 year. The outcomes of the study were to determine variables correlated with AKI onset, and with eGFR decay at 1 year. The proportion of AKI was 64%. Logistic analyses showed that baseline eGFR independently predicted AKI (odds ratio 1.04, 95%CI 1.02:1.06). Moreover, AKI (Beta −16, 95%CI −21:−11), baseline eGFR (Beta −0.42, 95%CI −0.52:−0.33), and the presence of arterial narrowing (Beta 10, 95%CI 4:15) were independently associated with eGFR decline. Our findings showed that AKI onset and eGFR decline were more likely to occur with higher baseline eGFR and lower CS, highlighting that RN in normal renal function patients represents a more traumatic event than its CKD counterpart.

Cystatin C predicts renal function impairment after partial or radical tumor nephrectomy

Purpose

To test the value of preoperative and postoperative cystatin C (CysC) as a predictor on kidney function after partial (PN) or radical nephrectomy (RN) in renal cell carcinoma (RCC) patients with normal preoperative renal function.

Methods

From 01/2011 to 12/2014, 195 consecutive RCC patients with a preoperative estimated glomerular filtration rate (eGFR) > 60 ml/min/1.73m² underwent surgical RCC treatment with either PN or RN. Logistic and linear regression models tested for the effect of CysC as a predictor of new-onset chronic kidney disease in follow-up (eGFR < 60 ml/min/1.73m²). Moreover, postoperative CysC and creatinine values were compared for kidney function estimation.

Results

Of 195 patients, 129 (66.2%) underwent PN. In postoperative and in follow-up setting (median 14 months, IQR 10–20), rates of eGFR < 60 ml/min/1.73m² were 55.9 and 30.2%. In multivariable logistic regression models, preoperative CysC [odds ratio (OR): 18.3] and RN (OR: 13.5) were independent predictors for a reduced eGFR < 60 ml/min/1.73m² in follow-up (both p < 0.01), while creatinine was not. In multivariable linear regression models, a difference of the preoperative CysC level of 0.1 mg/dl estimated an eGFR decline in follow-up of about 5.8 ml/min/1.73m². Finally, we observed a plateau of postoperative creatinine values in the range of 1.2–1.3 mg/dl, when graphically depicted vs. postoperative CysC values (‘creatinine blind area’).

Conclusion

Preoperative CysC predicts renal function impairment following RCC surgery. Furthermore, CysC might be superior to creatinine for renal function monitoring in the early postoperative setting.

Predictive models for chronic kidney disease after radical or partial nephrectomy in renal cell cancer using early postoperative serum creatinine levels

Background

Several predictive factors for chronic kidney disease (CKD) following radical nephrectomy (RN) or partial nephrectomy (PN) have been identified. However, early postoperative laboratory values were infrequently considered as potential predictors. Therefore, this study aimed to develop predictive models for CKD 1 year after RN or PN using early postoperative laboratory values, including serum creatinine (SCr) levels, in addition to preoperative and intraoperative factors. Moreover, the optimal SCr sampling time point for the best prediction of CKD was determined.

Methods

Data were retrospectively collected from patients with renal cell cancer who underwent laparoscopic or robotic RN (n = 557) or PN (n = 999). Preoperative, intraoperative, and postoperative factors, including laboratory values, were incorporated during model development. We developed 8 final models using information collected at different time points (preoperative, postoperative day [POD] 0 to 5, and postoperative 1 month). Lastly, we combined all possible subsets of the developed models to generate 120 meta-models. Furthermore, we built a web application to facilitate the implementation of the model.

Results

The magnitude of postoperative elevation of SCr and history of CKD were the most important predictors for CKD at 1 year, followed by RN (compared to PN) and older age. Among the final models, the model using features of POD 4 showed the best performance for correctly predicting the stages of CKD at 1 year compared to other models (accuracy: 79% of POD 4 model versus 75% of POD 0 model, 76% of POD 1 model, 77% of POD 2 model, 78% of POD 3 model, 76% of POD 5 model, and 73% in postoperative 1 month model). Therefore, POD 4 may be the optimal sampling time point for postoperative SCr. A web application is hosted at https://dongy.shinyapps.io/aki_ckd.

Conclusions

Our predictive model, which incorporated postoperative laboratory values, especially SCr levels, in addition to preoperative and intraoperative factors, effectively predicted the occurrence of CKD 1 year after RN or PN and may be helpful for comprehensive management planning.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02976-2.

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.

From kidney injury to kidney cancer

Epidemiologic studies document strong associations between acute or chronic kidney injury and kidney tumors. However, whether these associations are linked by causation, and in which direction, is unclear. Accumulating data from basic and clinical research now shed light on this issue and prompt us to propose a new pathophysiological concept with immanent implications in the management of patients with kidney disease and patients with kidney tumors. As a central paradigm, this review proposes the mechanisms of kidney damage and repair that are active during acute kidney injury but also during persistent injuries in chronic kidney disease as triggers of DNA damage, promoting the expansion of (pre-)malignant cell clones. As renal progenitors have been identified by different studies as the cell of origin for several benign and malignant kidney tumors, we discuss how the different types of kidney tumors relate to renal progenitors at specific sites of injury and to germline or somatic mutations in distinct signaling pathways. We explain how known risk factors for kidney cancer rather represent risk factors for kidney injury as an upstream cause of cancer. Finally, we propose a new role for nephrologists in kidney cancer (i.e., the primary and secondary prevention and treatment of kidney injury to reduce incidence, prevalence, and recurrence of kidney cancer).

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.

The impact of visceral adipose tissue on post -operative renal Function after Radical Nephrectomy for renal cell carcinoma

BACKGROUND

The objective of this study was to evaluate the usefulness of pre-operative visceral (VAT) and subcutaneous adipose tissue (SAT) evaluation in the prediction of Acute Kidney Injury (AKI) and decrease of eGFR at 12 months after radical nephrectomy (RN).

METHODS

We relied on 112 patients who underwent RN between January 2010 and March 2017 at a single institution. Images from the pre-operatory CT scan were analyzed and both SAT and VAT assessments were carried out on a cross-sectional plane. eGFR was measured before surgery, at 7 days, and 12 months after surgery. ROC analysis was used to compare the diagnostic value of BMI, VAT ratio, and abdominal circumference in predicting AKI. Logistic regression models were fitted to predict the new onset of AKI, and the progression from chronic kidney disease (CKD) stage 1-3a to CKD stage 3b or from 3b to 4 at 12 months follow-up. Two logistic regression models were also performed to assess the predictors for AKI and CKD stage progression. The predictive accuracy was quantified using the receiver operating characteristic-derived area under the curve.

RESULTS

Sixty-six patients (58.9%) had AKI after RN. Thirty-five (31.3%) patients were upgraded to CKD IIIb or from CKD stage IIIb to CKD IV. In the ROC analysis, VAT% performed better than the BMI and abdominal circumference (AUC = 0.66 vs 0.49 and 0.54, respectively). At multivariable analyses, VAT reached an independent predictor status for AKI (OR: 1.03) and for CKD stage at 12 months Follow-up (OR: 1.05). Inclusion of VAT% into the multivariable models was associated with the highest accuracy both for AKI (AUC = 0.700 vs 0.570) and CKD stage progression (AUC = 0.848 vs 0.800).

CONCLUSIONS

In patients undergoing RN, preoperative visceral adipose tissue ratio significantly predicts AKI incidence and is significantly predictive of 12 months CKD stage worsening.

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.

Onconephrology

Current advances in cancer chemotherapeutics have remarkably helped in rapid and definitive treatment options. However, these potent chemotherapeutics have been associated with severe renal toxicities that later impact treatment options. Acute kidney injury is common in patients with cancer. In hospitalized patients with cancer, acute kidney injury is associated with increased morbidity, mortality, length of stay, and costs. This article provides an overview of acute kidney injury caused by cancer or its treatment, including prerenal, tubular, glomerular diseases, infiltrative disease, tumor lysis syndrome, anticancer drug nephrotoxicity, hematopoietic stem cell transplantation-related acute kidney injury, and cancer-associated thrombotic microangiopathy.

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 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.

Robust Association between Acute Kidney Injury after Radical Nephrectomy and Long-term Renal Function

The association between acute kidney injury (AKI) and long-term renal function after radical nephrectomy has not been evaluated fully. We reviewed 558 cases of radical nephrectomy. Postoperative AKI was defined by the Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria. Values of estimated glomerular filtration rate (eGFR) were collected up to 36 months (median 35 months) after surgery. The primary outcome was new-onset chronic kidney disease (CKD) stage 3a or higher or all-cause mortality within three years after nephrectomy. The functional change ratio (FCR) of eGFR was defined as the ratio of the most recent GFR (24-36 months after surgery) to the new baseline during 3-12 months. A multivariable Cox proportional hazard regression analysis for new-onset CKD and a multivariable linear regression analysis for FCR were performed to evaluate the association between AKI and long-term renal outcomes. A correlation analysis was performed with the serum creatinine ratio and used to determine AKI and FCR. AKI occurred in 43.2% (n = 241/558) and our primary outcome developed in 40.5% (n = 226/558) of patients. The incidence of new-onset CKD was significantly higher in patients with AKI than those without at all follow-up time points after surgery. The Cox regression analysis showed a graded association between AKI and our primary outcome (AKI stage 1: Hazard ratio 1.71, 95% confidence interval 1.25-2.32; AKI stage 2 or 3: Hazard ratio 2.72, 95% confidence interval 1.78-4.10). The linear regression analysis for FCR showed that AKI was significantly associated with FCR (β = -0.168 ± 0.322, p = 0.011). There was a significant negative correlation between the serum creatinine ratio and FCR. In conclusion, our analysis demonstrated a robust and graded association between AKI after radical nephrectomy and long-term renal functional deterioration.

The adjuvant treatment of kidney cancer: a multidisciplinary outlook

Approximately 70% of cases of kidney cancer are localized or locally advanced at diagnosis. Among patients who undergo surgery for these cancers, 30-35% will eventually develop potentially fatal metachronous distant metastases. Effective adjuvant treatments are urgently needed to reduce the risk of recurrence of kidney cancer and of dying of metastatic disease. To date, almost all of the tested adjuvant agents have failed to demonstrate any benefit. Only two trials of an autologous renal tumour cell vaccine and of the vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor sunitinib have shown positive results, but these have been criticized for methodological reasons and conflicting data, respectively. The results of two additional trials of targeted agents as adjuvant therapies have not yet been published. Novel immune checkpoint inhibitors are promising approaches to adjuvant therapy in kidney cancer, and a number of trials are now underway. An important component of the management of patients with kidney cancer, particularly those who undergo radical resection for localized renal cell carcinoma, is the preservation of kidney function to reduce morbidity and mortality. The optimal management of these patients therefore requires a multidisciplinary approach involving nephrologists, oncologists, urologists and pathologists.

Acute kidney injury in cancer patients

The increasing prevalence of neoplasias is associated with new clinical challenges, one of which is acute kidney injury (AKI). In addition to possibly constituting a clinical emergency, kidney failure significantly interferes with the choice and continuation of antineoplastic therapy, with prognostic implications in cancer patients. Some types of neoplasia are more susceptible to AKI, such as multiple myeloma and renal carcinoma. In cancer patients, AKI can be divided into pre-renal, renal (intrinsic), and post-renal. Conventional platinum-based chemotherapy and new targeted therapy agents against cancer are examples of drugs that cause an intrinsic renal lesion in this group of patients. This topic is of great importance to the daily practice of nephrologists and even constitutes a subspecialty in the field, the onco-nephrology.

Improved nephrology referral of chronic kidney disease patients: potential role of smartphone apps

In chronic kidney disease (CKD), referral to nephrology is based on Kidney Disease: Improving Global Outcomes 2012 guidelines and is generally indicated when the estimated glomerular filtration rate (eGFR) is <30 mL/min/1.73 m2 or when there is a rapid decline of eGFR, elevated urinary albumin:creatinine ratio (>300 mg/g) or other 'alert' signs such as the presence of urinary red blood cell casts. Since eGFR declines with ageing in otherwise healthy individuals, we propose that the eGFR threshold for nephrology referral should be adjusted according to age. According to current recommendations, young patients without rapidly progressing CKD are referred more often to nephrology when CKD is more severe, compared with age-matched controls with normal eGFRs, than elderly CKD patients. In this commentary, we discuss the age factor and other specific situations not considered in current guidelines for nephrology referral of CKD patients.

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.

Onconephrology: An Evolving Field

This column is supplied by Ala Abudayyeh, MD, an internal medicine physician and associate professor of nephrology at The University of Texas MD Anderson Cancer Center in Houston, Texas. Dr. Abudayyeh earned her medical degree at the University of Texas-Houston Medical School and completed both her internal medicine residency and nephrology fellowship at Baylor College of Medicine in Houston. She is board certified in internal medicine and nephrology and joined the University of Texas MD Anderson Cancer Center in 2012.

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.

Acute Kidney Injury Adjusted for Parenchymal Mass Reduction and Long-Term Renal Function after Partial Nephrectomy

We sought to evaluate the association of postoperative acute kidney injury (AKI) adjusted for parenchymal mass reduction with long-term renal function in patients undergoing partial nephrectomy. A total of 629 patients undergoing partial nephrectomy were reviewed. Postoperative AKI was defined by the Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria, by using either the unadjusted or adjusted baseline serum creatinine level, accounting for renal parenchymal mass reduction. Estimated glomerular filtration rates (eGFRs) were followed up to 61 months (median 28 months) after surgery. The primary outcome was the functional change ratio (FCR) of eGFR calculated by the ratio of the most recent follow-up value, at least 24 months after surgery, to eGFR at 3-12 months after surgery. Multivariable linear regression analysis was performed to evaluate whether unadjusted or adjusted AKI was an independent predictor of FCR. As a sensitivity analysis, functional recovery at 3-12 months after surgery compared to the preoperative baseline was analyzed. Median parenchymal mass reduction was 11%. Unadjusted AKI occurred in 16.5% (104/625) and adjusted AKI occurred in 8.6% (54/629). AKI using adjusted baseline creatinine was significantly associated with a long-term FCR (β = -0.129 ± 0.026, p < 0.001), while unadjusted AKI was not. Adjusted AKI was also a significant predictor of functional recovery (β = -0.243 ± 0.106, p = 0.023), while unadjusted AKI was not. AKI adjusted for the parenchymal mass reduction was significantly associated with a long-term functional decline after partial nephrectomy. A creatinine increase due to remaining parenchymal ischemic injury may be important in order to predict long-term renal functional outcomes after partial nephrectomy.

Predicting acute kidney injury after robot-assisted partial nephrectomy: Implications for patient selection and postoperative management

BACKGROUND

Acute Kidney Injury (AKI) is a common occurrence after partial nephrectomy and is a significant risk factor for chronic kidney disease. We aimed to create a model that predicts postoperative AKI in patients undergoing robot-assisted partial nephrectomy (RAPN).

METHODS

We identified 1,190 patients who underwent RAPN between 2008 and 2017 from a multicenter database. AKI was defined as a >25% reduction in eGFR from pre-RAPN to discharge. A nomogram was built based on a binary logistic regression that ultimately included age, sex, BMI, diabetes, baseline eGFR, and RENAL Nephrometry score. Internal validation was performed using the leave-one-out cross validation. Calibration was graphically investigated. The decision curve analysis was used to evaluate the net clinical benefit; a classification tree was used to identify risk categories. The same model was fit adding ischemia time during RAPN.

RESULTS

Median (IQR) age at surgery was 61 (50, 68) years; 505 (42%) patients were female, while 685 (58%) were male. Median (IQR) ischemia time during RAPN was 14 (10, 18) min. postoperative AKI occurred in 274 (23%) patients. All variables fitted in the model emerged as predictors of AKI (all P ≤ 0.005) and all were considered to build a nomogram. After internal validation, the area under the curve was 73%. The model demonstrated excellent calibration and improved clinical risk prediction at the decision curve analysis. In the low, intermediate, and high-risk groups the postoperative AKI rates were: 10%, 30%, and 48%, respectively. Adding ischemia time to the preoperative model fit the data better (likelihood ratio test: P < 0.001) and yielded an incremental area under the curve of 3% (95% confidence interval: 1, 5%) CONCLUSION: We developed a nomogram that accurately predicts AKI in patients undergoing RAPN. This model might serve (1) in the preoperative setting: for counsel patients according to their preoperative AKI risk (2) in the immediate postoperative: for identifying patients who would benefit from an early multidisciplinary evaluation, when considering also ischemia time.

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.

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.

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.

Effect of prolonged inspiratory time on gas exchange during robot-assisted laparoscopic urologic surgery

BACKGROUND

Gas exchange disturbance may develop during urologic robotic laparoscopic surgery with the patient in a steep Trendelenburg position. This study investigated whether prolonged inspiratory time could mitigate gas exchange disturbances including hypercapnia.

METHODS

In this randomized cross-over trial, 32 patients scheduled for robot-assisted urologic surgery were randomized to receive an inspiratory to expiratory time ratio (I:E) of 1:1 for the first hour of pneumoperitoneum followed by 1:2 for last period of surgery (group A, n = 17) or I:E of 1:2 followed by 1:1 (group B, n = 15). Arterial blood gas analysis, airway pressure and hemodynamic variables were assessed at four time points (T1: 10 min after induction of general anesthesia, T2: 1 h after the initiation of pneumoperitoneum, T3: 1 h after T2 and T4: at skin closure). The carry over effect of initial I:E was also evaluated over the next hour through arterial blood gas analysis.

RESULTS

There was a significant decrease in partial pressure of oxygen in arterial blood (PaO₂) for both groups at T2 and T3 compared to T1 but in group B the PaO₂ at T4 was not decreased from the baseline. Partial pressure of carbon dioxide in arterial blood (PaCO₂) increased with I:E of 1:2 but did not significantly increase with I:E of 1:1; however, there were no differences in PaO₂ and PaCO₂ between the groups.

CONCLUSION

Decreased oxygenation by pneumoperitoneum was improved and PaCO₂ did not increase after 1 h of I:E of 1:1; however, the effect of equal ratio ventilation longer than 1 h remains to be determined. There was no carryover effect of the two different I:E ratios.

Outcome Measures Used to Report Kidney Function in Studies Investigating Surgical Management of Kidney Tumours: A Systematic Review

CONTEXT

Most practice decisions relevant to preserving kidney function in patients managed surgically for kidney tumours are driven by observational studies. A wide range of outcome measures are used in these studies, which reduces comparability and increases the risk of reporting bias.

OBJECTIVE

To comprehensively and succinctly describe the outcomes used to evaluate kidney function in studies evaluating surgical management of kidney tumours.

EVIDENCE ACQUISITION

Electronic search of the PubMed database was conducted to identify studies with at least one measure of kidney function in patients managed surgically for kidney tumours, published between January 2000 and September 2017. Abstracts were initially screened for eligibility. Full texts of articles were then evaluated in more detail for inclusion. A narrative synthesis of the evidence was conducted.

EVIDENCE SYNTHESIS

A total of 312 studies, involving 127905 participants, were included in this review. Most were retrospective (n=274) studies and conducted in a single centre (n=264). Overall, 78 unique outcome measures were identified, which were grouped into six outcome categories. Absolute postoperative kidney function (n=187), relative kidney function (n=181), and postoperative chronic kidney disease (n=131) were most frequently reported. Kidney function was predominantly quantified using estimated glomerular filtration rate or creatinine clearance (n=255), most using the modification of diet in renal disease equation (n=182). Only 70 studies provided rationale for specific outcome measures used.

CONCLUSIONS

There is significant variability in the reporting and quantification of kidney function in studies evaluating patients managed surgically for kidney tumours. A standardised approach to measuring and reporting kidney function will increase the effectiveness of outcomes reported and improve relevance of research findings within a clinical context.

PATIENT SUMMARY

Although we know that the removal of a kidney can reduce kidney function, clinical significance of various approaches is a matter of debate. This article demonstrates significant variability in the way kidney function was reported across all studies of patients with kidney cancer undergoing surgery, indicating a need for standardisation.