Impact of Acute Kidney Injury and Its Duration on Long-term Renal Function After Partial Nephrectomy

Assessing Functional Outcomes of Partial Versus Radical Nephrectomy for T1b-T2 Renal Masses: Results from a Multi-institutional Collaboration

BACKGROUND

Deterioration of renal function is associated with increased all-cause mortality. In renal masses larger than 4 cm, whether partial versus radical nephrectomy (PN vs. RN) might affect long-term functional outcomes is unknown. This study tested the association between PN versus RN and postoperative acute kidney injury (AKI), recovery of at least 90% of the preoperative estimated glomerular filtration rate (eGFR) at 1 year, upstaging of chronic kidney disease (CKD) one stage or more at 1 year, and eGFR decline of 45 ml/min/1.73 m2 or less at 1 year.

METHODS

Data from 23 high-volume institutions were used. The study included only surgically treated patients with single, unilateral, localized, clinical T1b-2 renal masses. Multivariable logistic regression analyses were performed.

RESULTS

Overall, 968 PN patients and 325 RN patients were identified. The rate of AKI was lower in the PN versus the RN patients (17% vs. 58%; p < 0.001). At 1 year after surgery, for the PN versus the RN patients, the rate for recovery of at least 90% of baseline eGFR was 51% versus 16%, the rate of CKD progression of ≥ 1 stage was 38% versus 65%, and the rate of eGFR decline of 45 ml/min/1.73 m2 or less was 10% versus 23% (all p < 0.001). Radical nephrectomy independently predicted AKI (odds ratio [OR], 7.61), 1-year ≥ 90% eGFR recovery (OR, 0.30), 1-year CKD upstaging (OR, 1.78), and 1-year eGFR decline of 45 ml/min/1.73 m2 or less (OR, 2.36) (all p ≤ 0.002).

CONCLUSIONS

For cT1b-2 masses, RN portends worse immediate and 1-year functional outcomes. When technically feasible and oncologically safe, efforts should be made to spare the kidney in case of large renal masses to avoid the hazard of glomerular function loss-related mortality.

Renal and major clinical outcomes and their determinants after nephrectomy in patients with pre-existing chronic kidney disease: A retrospective cohort study

The consequences of partial nephrectomy (PN) compared to radical nephrectomy (RN) are less documented in patients with pre-existing chronic kidney disease (CKD) or with solitary kidney (SK). We assessed renal outcomes, and their determinants, after PN or RN in a retrospective cohort of patients with moderate-to-severe CKD (RN-CKD and PN-CKD) or SK (PN-SK). All surgical procedures conducted between 2013 and 2018 in our institution in patients with pre-operative estimated glomerular filtration rate (eGFR)<60 mL/min/1.73m2 or with SK were included. The primary outcome was a composite criterion including CKD progression or major adverse cardio-vascular events (MACE) or death, assessed one year after surgery. Predictors of the primary outcome were determined using multivariate analyses. A total of 173 procedures were included (67 RN, and 106 PN including 27 SK patients). Patients undergoing RN were older, with larger tumors. Preoperative eGFR was not significantly different between the groups. One year after surgery, PN-CKD was associated with lower rate of the primary outcome compared to RN-CKD (43% vs 71% p = 0.007). In multivariate analysis, independent risk factors for the primary outcome were postoperative AKI (stage 1 to stage 3 ranging from OR = 8.68, 95% CI 3.23-23.33, to OR = 28.87, 95% CI 4.77-167.61), larger tumor size (OR = 1.21 per cm, 95% CI 1.02-1.45), while preoperative eGFR, age, sex, diabetes mellitus, and hypertension were not. Postoperative AKI after PN or RN was the major independent determinant of worse outcomes (CKD progression, MACE, or death) one year after surgery.

Acute Kidney Injury Duration and 20-Year Risks of CKD and Cardiovascular Disease

Introduction

Acute kidney injury (AKI) is associated with chronic kidney disease (CKD) and cardiovascular disease (CVD); however, it is unclear whether AKI duration affects the long-term risks of CKD and CVD. Therefore, we performed a population-based cohort study examining the associations between AKI duration and CKD and CVD.

Methods

We identified patients with laboratory-recorded AKI in Denmark from 1990 through 2018. AKIs were categorized as rapid reversal AKI (≤48 hours), persistent AKI (2-7 days), and acute kidney disease (AKD) (>7 days). We estimated 20-year risks and adjusted hazard ratios (aHRs) of incident CKD and CVD.

Results

The study comprised 169,582 patients with AKI, with 100,478 and 76,838 included in the analysis of CKD and CVD, respectively. The 20-year risks of CKD were 26.3%, 29.5%, and 28.7% for rapid reversal AKI, persistent AKI, and AKD, respectively. Compared with rapid reversal AKI, aHRs were 1.13 (95% confidence interval [CI], 1.08-1.19) for persistent AKI and 1.36 (95% CI, 1.30-1.41) for AKD. Risks and rates of overall CVD were similar for rapid reversal AKI, persistent AKI, and AKD. However, persistent AKI was associated with a slightly increased aHR of heart failure (1.09; 95% CI, 1.02-1.16), and aHRs of heart failure, ischemic heart disease, and peripheral artery disease were slightly increased for AKD (1.09 [95% CI, 1.03-1.15], 1.11 [95% CI, 1.03-1.19], and 1.10 [95% CI, 1.02-1.17], respectively).

Conclusion

AKI duration was associated with development of CKD, but not overall CVD; however, rates of heart failure, ischemic heart disease, and peripheral artery disease increased slightly with AKI duration.

Functional recovery after partial nephrectomy in a solitary kidney

OBJECTIVES

Partial nephrectomy (PN) is the reference standard for renal mass in a solitary kidney (RMSK), although factors determining functional recovery in this setting remain poorly defined.

PATIENTS/METHODS

Single center, retrospective analysis of 841 RMSK patients (1975-2022) managed with PN with functional data, including 361/435/45 with cold/warm/zero ischemia, respectively. A total of 155 of these patients also had necessary studies for detailed analysis of parenchymal volume preserved. Acute kidney injury (AKI) was classified by RIFLE (Risk/Injury/Failure/Loss/Endstage). Recovery-from-ischemia (Rec-Ischemia) was defined as glomerular filtration rate (GFR) saved normalized by parenchymal volume saved. Logistic regression identified predictive factors for AKI and predictors of Rec-Ischemia were analyzed by multivariable linear regression.

RESULTS

Overall, median preoperative GFR was 56.7 ml/min/1.73m2 and new-baseline and 5-year GFRs were 43.1 and 44.5 ml/min/1.73m2, respectively. Median follow-up was 55 months; 5-year dialysis-free survival was 97%. In the detailed analysis cohort, a primary focus of this study, median warm (n = 70)/cold (n = 85) ischemia times were 25/34 minutes, respectively; and median preoperative, new-baseline and 5-year GFRs were 57.8, 45.0, and 41.7 ml/min/1.73m2, respectively. Functional recovery correlated strongly with parenchymal volume preserved (r = 0.84, p < 0.001). Parenchymal volume loss accounted for 69% of the total median GFR decline associated with PN, leaving only 3 to 4 ml/min/1.73m2 attributed to ischemia and other factors. AKI occurred in 52% of patients and the only independent predictor of AKI was ischemia time. Independent predictors of reduced Rec-Ischemia were increased age, warm ischemia, and AKI.

CONCLUSION

The main determinant of functional recovery after PN in RMSK is parenchymal volume preservation. Type/duration of ischemia, AKI, and age also correlated, although altogether their contributions were less impactful. Our findings suggest multiple opportunities for optimizing functional outcomes although preservation of parenchymal volume remains predominant. Long-term function generally remains stable with dialysis only occasionally required.

A new machine-learning model to predict long-term renal function impairment after minimally invasive partial nephrectomy: the Fundació Puigvert predictive model

PURPOSE

To provide a new model to predict long-term renal function impairment after partial nephrectomy (PN).

METHODS

Data of consecutive patients who underwent minimally invasive PN from 2005 to 2022 were analyzed. A minimum of 12 months of follow-up was required. We relied on a machine-learning algorithm, namely classification and regression tree (CART), to identify the predictors and associated clusters of chronic kidney disease (CKD) stage migration during follow-up.

RESULTS

568 patients underwent minimally invasive PN at our center. A total of 381 patients met our inclusion criteria. The median follow-up was 69 (IQR 38-99) months. A total of 103 (27%) patients experienced CKD stage migration at last follow-up. Progression of CKD stage after surgery, ACCI and baseline CKD stage were selected as the most informative risk factors to predict CKD progression, leading to the creation of four clusters. The progression of CKD stage rates for cluster #1 (no progression of CKD stage after surgery, baseline CKD stage 1-2, ACCI 1-4), #2 (no progression of CKD stage after surgery, baseline CKD stage 1-2, ACCI ≥ 5), #3 (no progression of CKD stage after surgery and baseline CKD stage 3-4-5) and #4 (progression of CKD stage after surgery) were 6.9%, 28.2%, 37.1%, and 69.6%, respectively. The c-index of the model was 0.75.

CONCLUSION

We developed a new model to predict long-term renal function impairment after PN where the perioperative loss of renal function plays a pivotal role to predict lack of functional recovery. This model could help identify patients in whom functional follow-up should be intensified to minimize possible worsening factors of renal function.

Risk factors and predictive model for acute kidney Injury Transition to acute kidney disease in patients following partial nephrectomy

PURPOSE

Acute kidney disease (AKD) is believed to be involved in the transition from acute kidney injury (AKI) to chronic kidney disease in general populations, but little is understood about this possibility among kidney surgical populations. This study aimed to elucidate the incidence of AKD after partial nephrectomy and risk factors that promote the AKI to AKD transition.

METHODS

From January 2010 to January 2020, this study retrospectively collected a dataset of consecutive patients with renal masses undergoing partial nephrectomy in 4 urological centers. Cox proportional regression analyses were adopted to identify risk factors that promoted the AKI to AKD transition. To avoid overfitting, the results were then verified by logistic least absolute shrinkage and selection operator (LASSO) regression. A nomogram was then constructed and validated for AKI to AKD transition prediction.

RESULTS

AKI and AKD occurred in 228 (21.4%) and 42 (3.9%) patients among a total of 1062 patients, respectively. In patients with AKI, multivariable Cox regression analysis and LASSO regression identified that age (HR 1.078, 1.029-1.112, p < 0.001), baseline eGFR (HR 1.015, 1.001-1.030, p < 0.001), RENAL score (HR1.612, 1.067-2.437, p = 0.023), ischemia time > 30 min (HR 7.284, 2.210-23.999, p = 0.001), and intraoperative blood loss > 300ml (HR 8.641, 2.751-27.171, p < 0.001) were risk factors for AKD transition. These five risk factors were then integrated into a nomogram. The nomogram showed excellent discrimination, calibration, and clinical net benefit ability.

CONCLUSION

Around 3.9% patients following partial nephrectomy would transit from AKI to AKD. Intraoperative blood loss and ischemia time need to be diminished to avoid on-going functional decline. Our nomogram can accurately predict the transition from AKI to AKD.

Parenchymal volume analysis to assess longitudinal functional decline following partial nephrectomy

OBJECTIVE

To identify factors associated with longitudinal ipsilateral functional decline after partial nephrectomy (PN).

PATIENTS AND METHODS

Of 1140 patients managed with PN (2012-2014), 349 (31%) had imaging/serum creatinine levels pre-PN, 1-12 months post-PN (new baseline), and >3 years later necessary for inclusion. Parenchymal-volume analysis was used to determine split renal function. Patients were grouped as having significant renal comorbidity (CohortSRC : diabetes mellitus with insulin-dependence or end-organ damage, refractory hypertension, or severe pre-existing chronic kidney disease) vs not having significant renal comorbidity (CohortNoSRC ) preoperatively. Multivariable regression was used to identify predictors of annual ipsilateral parenchymal atrophy and functional decline relative to new baseline values post-PN, after the kidney had healed.

RESULTS

The median follow-up was 6.3 years with 87/226/36 patients having cold/warm/zero ischaemia. The median cold/warm ischaemia times were 32/22 min. Overall, the median tumour size was 3.0 cm. The preoperative glomerular filtration rate (GFR) and new baseline GFR (NBGFR) were 81 and 71 mL/min/1.73 m2 , respectively. After establishment of the NBGFR, the median loss of global and ipsilateral function was 0.7 and 0.4 mL/min/1.73 m2 /year, respectively, consistent with the natural ageing process. Overall, the median ipsilateral parenchymal atrophy was 1.2 cm3 /year and accounted for a median of 53% of the annual functional decline. Significant renal comorbidity, age, and warm ischaemia were independently associated with ipsilateral parenchymal atrophy (all P < 0.01). Significant renal comorbidity and ipsilateral parenchymal atrophy were independently associated with annual ipsilateral functional decline (both P < 0.01). Annual median ipsilateral parenchymal atrophy and functional decline were both significantly increased for CohortSRC compared to CohortNoSRC (2.8 vs 0.9 cm3 , P < 0.01 and 0.90 vs 0.30 mL/min/1.73 m2 /year, P < 0.01, respectively).

CONCLUSIONS

Longitudinal renal function following PN generally follows the normal ageing process. Significant renal comorbidities, age, warm ischaemia, and ipsilateral parenchymal atrophy were the most important predictors of ipsilateral functional decline following establishment of NBGFR.

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.

New-onset Chronic Kidney Disease After Surgery for Localised Renal Masses in Patients with Two Kidneys and Preserved Renal Function: A Contemporary Multicentre Study

Background

There is a lack of evidence on acute kidney injury (AKI) and new-onset chronic kidney disease (CKD) after surgery for localised renal masses (LRMs) in patients with two kidneys and preserved baseline renal function.

Objective

To evaluate the prevalence and risk of AKI and new-onset clinically significant CKD (csCKD) in patients with a single renal mass and preserved renal function after being treated with partial (PN) or radical (RN) nephrectomy.

Design setting and participants

We queried our prospectively maintained databases to identify patients with a preoperative estimated glomerular filtration rate (eGFR) of ≥60 ml/min/1.73 m² and a normal contralateral kidney who underwent PN or RN for a single LRM (cT1-T2N0M0) between January 2015 and December 2021 at four high-volume academic institutions.

Intervention

PN or RN.

Outcome measurements and statistical analysis

The outcomes of this study were AKI at hospital discharge and the risk of new-onset csCKD, defined as eGFR <45 ml/min/1.73 m², during the follow-up. Kaplan-Meier curves were used to examine csCKD-free survival according to tumour complexity. A Multivariable logistic regression analysis assessed the predictors of AKI, while a multivariable Cox regression analysis assessed the predictors of csCKD. Sensitivity analyses were performed in patients who underwent PN.

Results and limitations

Overall, 2469/3076 (80%) patients met the inclusion criteria. At hospital discharge, 371/2469 (15%) developed AKI (8.7% vs 14% vs 31% in patients with low- vs intermediate- vs high-complexity tumours, p < 0.001). At the multivariable analysis, body mass index, history of hypertension, tumour complexity, and RN significantly predicted the occurrence of AKI. Among 1389 (56%) patients with complete follow-up data, 80 events of csCKD were recorded. The estimated csCKD-free survival rates were 97%, 93% and 86% at 12, 36, and 60 mo, respectively, with significant differences between patients with high- versus low-complexity and high- versus intermediate-complexity tumours (p = 0.014 and p = 0.038, respectively). At the Cox regression analysis, age-adjusted Charlson Comorbidity Index, preoperative eGFR, tumour complexity, and RN significantly predicted the risk of csCKD during the follow-up. The results were similar in the PN cohort. The main limitation of the study was the lack of data on eGFR trajectories within the 1st year after surgery and on long-term functional outcomes.

Conclusions

The risk of AKI and de novo csCKD in elective patients with an LRM and preserved baseline renal function is not clinically negligible, especially in those with higher-complexity tumours. While baseline nonmodifiable patient/tumour-related characteristics modulate this risk, PN should be prioritised over RN to maximise nephron preservation if oncological outcomes are not jeopardised.

Patient summary

In this study, we evaluated how many patients with a localised renal mass and two functioning kidneys, who were candidates for surgery at four referral European centres, experienced acute kidney injury at hospital discharge and significant renal functional impairment during the follow-up. We found that the risk of acute kidney injury and clinically significant chronic kidney disease in this patient population is not negligible, and was associated with specific baseline patient comorbidities, preoperative renal function, tumour anatomical complexity, and surgery-related factors, in particular the performance of radical nephrectomy.

Long-Term Renal Function Following Renal Cancer Surgery: Historical Perspectives, Current Status, and Future Considerations

Knowledge of functional recovery after partial (PN) and radical nephrectomy for renal cancer has advanced considerably, with PN now established as the reference standard for most localized renal masses. However, it is still unclear whether PN provides an overall survival benefit in patients with a normal contralateral kidney. While early studies seemingly demonstrated the importance of minimizing warm-ischemia time during PN, multiple new investigations over the last 10 years have proven that parenchymal mass lost is the most important predictor of new baseline renal function. Minimizing loss of parenchymal mass during resection and reconstruction is the most important controllable aspect of long-term post-operative renal function preservation.

Downregulation of G protein-coupled receptor kinase 4 protects against kidney ischemia-reperfusion injury

Ischemia/reperfusion injury of the kidney is associated with high morbidity and mortality, and treatment of this injury remains a challenge. G protein-coupled receptor kinase 4 (GRK4) plays a vital role in essential hypertension and myocardial infarction, but its function in kidney ischemia/reperfusion injury remains undetermined. Among the GRK subtypes (GRK2-6) expressed in kidneys, the increase in GRK4 expression was much more apparent than that of the other four GRKs 24 hours after injury and was found to accumulate in the nuclei of injured mouse and human renal tubule cells. Gain- and loss-of-function experiments revealed that GRK4 overexpression exacerbated acute kidney ischemia/reperfusion injury, whereas kidney tubule-specific knockout of GRK4 decreased injury-induced kidney dysfunction. Necroptosis was the major type of tubule cell death mediated by GRK4, because GRK4 significantly increased receptor interacting kinase (RIPK)1 expression and phosphorylation, subsequently leading to RIPK3 and mixed lineage kinase domain-like protein (MLKL) phosphorylation after kidney ischemia/reperfusion injury, but was reversed by necrostatin-1 pretreatment (an RIPK1 inhibitor). Using co-immunoprecipitation, mass spectrometry, and siRNA screening studies, we identified signal transducer and activator of transcription (STAT)1 as a GRK4 binding protein, which co-localized with GRK4 in the nuclei of renal tubule cells. Additionally, GRK4 phosphorylated STAT1 at serine 727, whose inactive mutation effectively reversed GRK4-mediated RIPK1 activation and tubule cell death. Kidney-targeted GRK4 silencing with nanoparticle delivery considerably ameliorated kidney ischemia/reperfusion injury. Thus, our findings reveal that GRK4 triggers necroptosis and aggravates kidney ischemia/reperfusion injury, and its downregulation may provide a promising therapeutic strategy for kidney protection.

Impact of Warm Ischemia on Acute Kidney Injury After Robotic Partial Nephrectomy Stratified by Baseline Kidney Function

Objectives: To evaluate the differences in baseline chronic kidney disease (CKD) status in correlations between warm ischemic time (WIT) and acute kidney injury (AKI) or acute/chronic renal function change after robot-assisted partial nephrectomy (RAPN). Methods: This study retrospectively recruited 1290 patients from a multi-institutional RAPN database. The patients were grouped into four preoperative CKD categories: CKD Group 1 (CKDG1), CKD Group 2 (CKDG2), CKD Group 3a (CKDG3a), and CKD Group 3b (CKDG3b). The correlation between WIT and the probability of AKI was assessed according to the baseline CKD grade, together with changes in serum creatinine (sCr) at the postoperative maximum and chronic renal function. Results: AKI was not observed in the CKDG1 group. The probability of AKI at WIT = 30 minutes was 5.6% for CKDG2, 8.5% for CKDG3a, and 11.6% for CKDG3b (all p < 0.05). WIT was an independent predictor of AKI occurrence in the multivariate model for these three CKD groups. Significant weak correlations were observed between WIT and sCr change for all four groups, with R² = 0.22 for CKDG1, R² = 0.16 for CKDG2, R² = 0.03 for CKDG3a, and R² = 0.09 for ≥CKDG3b. For chronic renal function, correlations were significant in CKDG2, CKDG3a, and ≥CKDG3b, yet R² was considered small in all cases (<0.1). Conclusions: The association between extended WIT and the probability of AKI increased in patients with more severe baseline CKD. The correlation between WIT and renal function was significant, yet clinically modest.

A comprehensive assessment of frailty status on surgical, functional and oncologic outcomes in patients treated with partial nephrectomy-A large, retrospective, single-center study

BACKGROUND

Partial nephrectomy (PN) is a challenging procedure, which can be associated with severe complications. In consequence, the search for accurate and independent indicators of unfavorable surgical outcomes appears warranted. We aimed at evaluating the impact of frailty status on surgical, functional and oncologic outcomes in patients undergoing PN for renal cell carcinoma (RCC).

METHODS

A retrospective, single-center study including 1,282 patients treated with PN for clinically localized cT₁ RCC was performed. The modified Frailty Index (mFI) was used to assess preoperative frailty. Multivariable logistic, Poisson and linear regression analyses(MVA) tested the effect of frailty on complications, acute kidney injury(AKI), renal function decline after PN. Cumulative incidence and competing-risk analyses investigated survival outcomes.

RESULTS

Of 1,282 patients, 220 (17%) were frail. Overall, 982 (76%) vs. 123 (9.6%) vs. 171 (13%) patients underwent open vs. laparoscopic vs. robot-assisted PN. Median follow-up was 66 (IQR: 35-107) months. At MVA, frailty status predicted increased risk of complications [Odds ratio (OR): 1.46, 95%CI 1.17-1.84; P < 0.001]. Moreover, frail patients were at higher risk of postoperative AKI (OR: 1.95, 95%CI 1.13-3.35; P = 0.01). In frail patients, renal function permanently decreased over time (P = 0.01) without any renal function plateau or improvement during the follow-up, which were instead observed in the nonfrail cohort. At competing-risks analyses, frailty status predicted higher risk of other-cause mortality [Hazard ratio (HR): 1.67, 95%CI 1.05-2.66; P = 0.02], but not of cancer-specific mortality (P = 0.3).

CONCLUSIONS

Frailty status predicts higher risk of adverse surgical outcomes after PN. Moreover, greater renal function decline was observed in frail patients, compared with nonfrail patients. Finally, the risk of OCM significantly overcomes the risk of dying due to RCC in frail patients.

Every decade counts: a narrative review of functional recovery after partial nephrectomy

OBJECTIVE

To provide a narrative review of the major advances regarding ischaemia and functional recovery after partial nephrectomy (PN), along with the ongoing controversies.

METHODS

Key articles reflecting major advances regarding ischaemia and functional recovery after PN were identified. Special emphasis was placed on contributions that changed perspectives about surgical management. Priority was also placed on randomized trials of off-clamp vs on-clamp cohorts.

RESULTS

A decade ago, 'Every minute counts' was published, showing strong correlations between duration of ischaemia and development of acute kidney injury (AKI) and chronic kidney disease after clamped PN. This reinforced perspectives that ischaemia was the main modifiable factor that could be addressed to improve functional outcomes and helped spur efforts towards reduced or zero ischaemia PN. These approaches were associated with strong functional recovery and some peri-operative risk, although they were generally safe in experienced hands. Further research demonstrated that, when parenchymal volume changes were incorporated into the analyses, ischaemia lost statistical significance, and percent parenchymal volume saved proved to be the main determinant. Cold ischaemia was confirmed to be highly protective, and limited warm ischaemia also proved to be safe. The reconstructive phase of PN, with avoidance of parenchymal devascularization, appears to be most important for functional outcomes. Randomized trials of on-clamp vs off-clamp PN have shown minimal impact of ischaemia on functional recovery.

CONCLUSIONS

The past decade has witnessed great progress regarding functional recovery after PN, with many lessons learned. However, there are still unanswered questions, including: What is the threshold of warm ischaemia at which irreversible ischaemic injury begins to develop? Are some cohorts at increased risk for AKI or irreversible ischaemic injury? and Which patients should be prioritized for zero-ischaemia PN?

Robot-assisted sutureless partial nephrectomy for the treatment of fifteen bilateral renal masses in a patient with Von Hippel-Lindau syndrome: a case report from a high-volume robotic center

Renal cell carcinoma is among major causes of death in patients with Von Hippel-Lindau (VHL) syndrome, and it usually presents with multiple and bilateral lesions that may require multiple renal surgeries. This, in turn, may compromise renal function, resulting in end-stage renal disease. To minimize renal function impairment in these patients, great importance is given to the preservation of functional parenchyma with the use of nephron-sparing techniques. Furthermore, new techniques such as off-clamp surgery, selective suturing or sutureless techniques may improve long-term functional outcomes. We described the case of a 27-year-old male patient with a family history of VHL disease affected by multiple, bilateral renal masses. He received bilateral, metachronous robot-assisted partial nephrectomies (RAPN) for a total of 15 renal lesions. No intra- or post-operative complications occurred, and the patient was discharged on the second postoperative day after both procedures. Serum creatinine after the second RAPN was 0.99 mg/dl (baseline value was 1.11 mg/dl). In patients with VHL syndrome and multiple renal lesions, robot-assisted partial nephrectomy, especially with the use of clampless and sutureless techniques, helps minimizing renal function impairment and should be performed when anatomically and technically feasible.

Impact of Blood Loss on Renal Function and Interaction with Ischemia Duration after Nephron-Sparing Surgery

OBJECTIVES

Nephron-sparing surgery (NSS) exposes the kidney to ischemia-reperfusion injury. Blood loss and hypotension are also associated with kidney injury. We aimed to test the hypothesis that, during NSS, both ischemia duration and blood loss significantly affect postoperative renal function and that their effects interact.

METHODS

Consecutive patients undergoing NSS were enrolled. The primary endpoint was renal function expressed as the absolute delta between preoperative and postoperative peak creatinine. We developed a generalized linear model with the ischemia duration and absolute hemoglobin difference as independent variables, their interaction term, and the RENAL score. The model was than expanded to include a history of hypertension (as a proxy for hypotension susceptibility) and related interaction terms. Further, we described the perioperative and mid-term oncological outcomes.

RESULTS

A total of 478 patients underwent NSS, and 209 (43.7%) required ischemia for a mean of 10.9 min (SD 8). Both the ischemia duration (partial eta 0.842, p = 0.006) and hemoglobin difference (partial eta 0.933, p = 0.029) significantly affected postoperative renal function, albeit without evidence of a significant interaction (p = 0.525). The RENAL score also significantly influenced postoperative renal function (p = 0.023). After the addition of a previous history of hypertension, the effects persisted, with a significant interaction between blood loss and a history of hypertension (p = 0.02).

CONCLUSIONS

Ischemia duration and blood loss had a similar impact on postoperative renal function, albeit without potentiating each other. While the surgical technique and ischemia minimization remain crucial to postoperative kidney function, increased awareness of conscious hemodynamic management appears warranted.

Organ Crosstalk in Acute Kidney Injury: Evidence and Mechanisms

Acute kidney injury (AKI) is becoming a public health problem worldwide. AKI is usually considered a complication of lung, heart, liver, gut, and brain disease, but recent findings have supported that injured kidney can also cause dysfunction of other organs, suggesting organ crosstalk existence in AKI. However, the organ crosstalk in AKI and the underlying mechanisms have not been broadly reviewed or fully investigated. In this review, we summarize recent clinical and laboratory findings of organ crosstalk in AKI and highlight the related molecular mechanisms. Moreover, their crosstalk involves inflammatory and immune responses, hemodynamic change, fluid homeostasis, hormone secretion, nerve reflex regulation, uremic toxin, and oxidative stress. Our review provides important clues for the intervention for AKI and investigates important therapeutic potential from a new perspective.

Clinical outcomes of robotic-assisted laparoscopic partial nephrectomy with renal hypothermia perfusion by renal artery balloon catheter in treating patients with complex renal tumors

Objective

This study aimed to investigate the safety and efficacy of renal hypothermic perfusion by renal artery balloon catheter during robot-assisted laparoscopic partial nephrectomy (P-RALPN) for patients with complex renal tumors.

Materials and methods

We retrospectively identified 45 patients with complex renal tumors who received standard robot-assisted laparoscopic partial nephrectomy (S-RALPN) and 11 patients treated with P-RALPN from September 2017 to October 2021. Preoperative patients’ characteristics and intraoperative surgical parameters including operating time, blood loss, hospitalization, pre- and post-surgical glomerular filtration rate (GFR), and postoperative survival time were collected and compared between the two groups. The patients’ body temperature, real-time kidney temperature, and short-term renal function were analyzed in the P-RALPN group.

Results

There was no statistically significant difference on median intraoperative estimated blood loss and postoperative hospitalization between the two groups. Patients who received P-RALPN had a slightly longer operative time than those who received S-RALPN (103.1 versus 125.9; p = 0.09). In the P-RALPN group, the volume of perfusion solution was 533.2 ml (range, 255.0–750.0 ml), the median temperature of kidney was 22.6°C (range, 21.7–24.1°C) after the kidney cools down, and the median minimum intraoperative temperature of patients was 36.1°C (range 35.2–36.7°C). The ischemia time in the S-RALPN group was markedly lower than that in the P-RALPN group (21.5 versus 34.8; p < 0.01). However, the loss of GFR was much higher for the S-RALPN group after the surgery. (28.9 versus 18.4; p < 0.01). Importantly, patients had similar postoperative survival time between the two groups (p = 0.42; HR = 0.27).

Conclusion

P-RALPN is a safe and feasible surgery in the treatment of patients with complex renal tumors, which provides a new operative approach for clinicians to treat these patients.

Mortality and costs associated with acute kidney injury following major elective, non-cardiac surgery

OBJECTIVE

This study evaluated postoperative AKI severity and its relation to short- and long-term patient outcomes.

DESIGN

A retrospective, single-center cohort study of patients undergoing surgery from January 2015 to May 2020.

SETTING

An urban, academic medical center.

PATIENTS

Adult patients undergoing elective, non-cardiac surgery at our institution with a postoperative length of stay (LOS) of at least 24 h were included. Patients were included in 1-year mortality analysis if their procedure occurred prior to June 2019.

INTERVENTIONS

None.

MEASUREMENTS

Postoperative AKI was identified and staged using the Kidney Disease Improving Global Outcomes definitions. The outcomes analyzed were in-hospital mortality, LOS, total cost of the surgical hospitalization, and 1-year mortality.

MAIN RESULTS

Of the 8887 patients studied, 648 (7.3%) had postoperative AKI. AKI was associated with severity-dependent increases in all outcomes studied. Patients with AKI had rates of in-hospital mortality of 2.0%, 3.8%, and 12.5% for stage 1, 2, and 3 AKI compared to 0.3% for patients without AKI. Mean total costs of the surgical hospitalization were $23,896 (SD $23,736) for patients without AKI compared to $33,042 (SD $27,115), $39,133 (SD $34,006), and $73,216 ($82,290) for patients with stage 1, 2, and 3 AKI, respectively. In the 6729 patients who met inclusion for 1-year mortality analysis, AKI was also associated with 1-year mortality rates of 13.9%, 19.4%, and 22.7% compared to 5.2% for patients without AKI. In multivariate models, stage 1 AKI patients still had a higher probability of 1-year mortality (OR 1.9, 95% CI 1.3-2.6, p < 0.001) in addition to $4391 of additional costs when compared to patients without AKI (95% CI $2498-$6285, p < 0.001).

CONCLUSIONS

All stages of postoperative AKI were associated with increased LOS, surgical hospitalization costs, in-hospital mortality, and 1-year mortality. These findings suggest that patients with even a low-grade or stage 1 AKI are at higher risk for short- and long-term complications.

The Effect of Polyphenols on Kidney Disease: Targeting Mitochondria

Mitochondrial function, including oxidative phosphorylation (OXPHOS), mitochondrial biogenesis, and mitochondria dynamics, are essential for the maintenance of renal health. Through modulation of mitochondrial function, the kidneys are able to sustain or recover acute kidney injury (AKI), chronic kidney disease (CKD), nephrotoxicity, nephropathy, and ischemia perfusion. Therapeutic improvement in mitochondrial function in the kidneys is related to the regulation of adenosine triphosphate (ATP) production, free radicals scavenging, decline in apoptosis, and inflammation. Dietary antioxidants, notably polyphenols present in fruits, vegetables, and plants, have attracted attention as effective dietary and pharmacological interventions. Considerable evidence shows that polyphenols protect against mitochondrial damage in different experimental models of kidney disease. Mechanistically, polyphenols regulate the mitochondrial redox status, apoptosis, and multiple intercellular signaling pathways. Therefore, this review attempts to focus on the role of polyphenols in the prevention or treatment of kidney disease and explore the molecular mechanisms associated with their pharmacological activity.

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.

Predicting acute kidney injury following open partial nephrectomy treatment using SAT-pruned explainable machine learning model

Background

One of the most prevalent complications of Partial Nephrectomy (PN) is Acute Kidney Injury (AKI), which could have a negative impact on subsequent renal function and occurs in up to 24.3% of patients undergoing PN. The aim of this study was to predict the occurrence of AKI following PN using preoperative parameters by applying machine learning algorithms.

Methods

We included all adult patients (n = 723) who underwent open PN in our department since 1995 and on whom we have data on the pre-operative renal function. We developed a random forest (RF) model with Boolean satisfaction-based pruned decision trees for binary classification (AKI or non-AKI). Hyper-parameter grid search was performed to optimize the model's performance. Fivefold cross-validation was applied to evaluate the model. We implemented a RF model with greedy feature selection to binary classify AKI and non-AKI cases based on pre-operative data.

Results

The best model obtained a 0.69 precision and 0.69 recall in classifying the AKI and non-AKI groups on average (k = 5). In addition, the model's probability to correctly classify a new prediction is 0.75. The proposed model is available as an online calculator.

Conclusions

Our model predicts the occurrence of AKI following open PN with (75%) accuracy. We plan to externally validate this model and modify it to minimally-invasive PN.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12911-022-01877-8.

Acute Kidney Injury and 3-Year Mortality in Elderly Patients After Non-cardiac Surgery

Objective

The present study aimed to investigate whether acute kidney injury (AKI) was associated with 3-year mortality in elderly patients after non-cardiac surgery.

Methods

The present study was a 3-year follow-up study of two randomized controlled trials. A total of 1,319 elderly patients who received non-cardiac surgery under general anesthesia were screened. AKI was diagnosed by the elevation of serum creatinine within a 7-day postoperative period according to Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. A long-term telephonic follow-up was undertaken by investigators who were not involved in the previous two trials and had no access to the study group assignment. The date of death was taken from the official medical death certificate. The primary outcome was to investigate the association between AKI and postoperative 3-year mortality using the multivariable Cox regression risk model.

Results

Of the 1,297 elderly patients (mean age 71.8 ± 7.2 years old) who were included in the study, the incidence of AKI was 15.5% (201/1297). Of the patients with AKI, 85% (170/201) were at stage 1, 10% (20/201) at stage 2, and 5% (11/201) at stage 3. The 3-year all-cause mortality was 28.9% (58/201) in patients with AKI and 24.0% (263/1,096) in patients without AKI (hazard ratio 1.247, 95% confidence interval 0.939–1.657, P = 0.128). The multivariable Cox regression showed that AKI was not associated with 3-year mortality after adjustment of confounding factors (adjusted hazard ratio 1.045, 95% confidence interval 0.780–1.401, P = 0.766).

Conclusions

AKI was a common postoperative complication, but it was not associated with 3-year mortality in elderly patients who underwent non-cardiac surgery. The low incidence of severe AKI might underestimate its underlying association with long-term mortality.

Estimated Glomerular Filtration Rate Decline at 1 Year After Minimally Invasive Partial Nephrectomy: A Multimodel Comparison of Predictors

Background

Long-term renal function after partial nephrectomy (PN) is difficult to predict as it is influenced by several modifiable and nonmodifiable variables, often intertwined in complex relations.

Objective

To identify variables influencing long-term renal function after PN and to assess their relative weight.

Design, setting, and participants

A total of 457 patients who underwent either robotic (n = 412) or laparoscopic PN (n = 45) were identified from a multicenter international database.

Outcome measurements and statistical analysis

The 1-yr estimated glomerular filtration rate (eGFR) percentage loss (1YPL), defined as the eGFR percentage change from baseline at 1 yr after surgery, was the outcome endpoint. Predictors evaluated included demographic data, tumor features, and operative and postoperative variables. Bayesian multimodel analysis of covariance was used to build all possible models and compare the fit of each model to the data via model Bayes factors. Bayesian model averaging was used to quantify the support for each predictor via the inclusion Bayes factor (BF_incl). High-dimensional undirected graph estimation was used for network analysis of conditional independence between predictors.

Results and limitations

Several models were found to be plausible for estimation of 1YPL. The best model, comprising postoperative eGFR percentage loss (PPL), sex, ischemia technique, and preoperative eGFR, was 207 times more likely than all the other models regarding relative predictive performance. Its components were part of the top 44 models and were the predictors with the highest BF_incl. The role of cold ischemia, solitary kidney status, surgeon experience, and type of renorraphy was not assessed.

Conclusions

Preoperative eGFR, sex, ischemia technique, and PPL are the best predictors of eGFR percentage loss at 1 yr after minimally invasive PN. Other predictors seem to be irrelevant, as their influence is insignificant or already nested in the effect of these four parameters.

Patient summary

Kidney function at 1 year after partial removal of a kidney depends on sex, the technique used to halt blood flow to the kidney during surgery, and kidney function at baseline and in the early postoperative period.

Impact of Trifecta definition on rates and predictors of "successful" robotic partial nephrectomy for localized renal masses: results from the Surface-Intermediate-Base Margin Score International Consortium

BACKGROUND

Over the years, five different Trifecta score definitions have been proposed to optimize the framing of "success" in partial nephrectomy (PN) field. However, such classifications rely on different metrics. The aim of the present study was to explore how the success rate of robotic PN, as well as its drivers, vary according to the currently available definitions of Trifecta.

METHODS

Data from consecutive patients with cT1-2N0M0 renal masses treated with robotic PN at 16 referral centers from September 2014 to March 2015 were prospectively collected. Trifecta rate was defined for each of the currently available definitions. Multivariable logistic regression analysis was used to evaluate possible predictors of "Trifecta failure" according to the different adopted formulation.

RESULTS

Overall, 289 patients met the inclusion criteria. Among the definitions, Trifecta rates ranged between 66.4% and 85.9%. Multivariable analysis showed that predictors for "Trifecta failure" were mainly tumor-related (i.e. tumor's nephrometry) for those Trifecta scores relying on WIT as a surrogate metric for postoperative renal function deterioration (definitions 1,2), while mainly surgery-related (i.e. ischemia time and excision strategy) for those including the percentage change in postoperative eGFR as the functional cornerstone of Trifecta (definitions 3-5).

CONCLUSIONS

There was large variability in rates and predictors of "unsuccessful PN" when using different Trifecta scores. Further research is needed to improve the value of the Trifecta metrics, integrating them into routine patient counseling and standardized assessment of surgical quality across institutions.

The association between modifiable perioperative parameters and renal function after nephrectomy

OBJECTIVE

To evaluate the association between intraoperative anaesthetic parameters, primarily intraoperative hypotension, and postoperative renal function in patients undergoing nephrectomy.

PATIENTS AND METHODS

We reviewed data from 3240 consecutive patients who underwent nephrectomy between 2010 and 2018. Anaesthetic parameters evaluated included duration of hypotension, tachycardia, hypothermia, volatile anaesthetic use and mean arterial pressure in the post-anaesthesia care unit. Outcomes included acute kidney injury (AKI) and estimated glomerular filtration rate (eGFR) within the first year after nephrectomy. Associations between anaesthetic parameters and outcomes were evaluated with multivariable logistic regression and generalised estimating equation, respectively, adjusted for predictors of renal function after nephrectomy.

RESULTS

Before nephrectomy, 677 (21%) patients had moderate-severe chronic kidney disease. A quarter of patients (n = 809) had postoperative AKI and 35% (n = 746) had Stage ≥3 chronic kidney disease 12-months after surgery. Only 12% of patients (n = 386) had >5 min of intraoperative hypotension. While not statistically significant, longer duration of intraoperative hypotension was associated with slightly higher rates of AKI (odds ratio [OR] per 10-min 1.14, 95% confidence interval [CI] 0.98, 1.32). Prolonged hypothermia was associated with increased rate of AKI (OR per 10-min 1.02, 95% CI 1.00, 1.04), and decreased eGFR (change in eGFR per 10-min -0.19, 95% CI -0.27, -0.12); however, these results have limited clinical significance.

CONCLUSIONS

Under current practice, intraoperative anaesthetic parameters are tightly maintained, restricting the significance of their effect on postoperative renal function. Future studies should evaluate whether haemodynamic parameters during the early postoperative period, when they are monitored less frequently, are associated with renal functional outcome.

Renal Oncocytoma: The Diagnostic Challenge to Unmask the Double of Renal Cancer

Renal oncocytoma represents the most common type of benign neoplasm that is an increasing concern for urologists, oncologists, and nephrologists due to its difficult differential diagnosis and frequent overtreatment. It displays a variable neoplastic parenchymal and stromal architecture, and the defining cellular element is a large polygonal, granular, eosinophilic, mitochondria-rich cell known as an oncocyte. The real challenge in the oncocytoma treatment algorithm is related to the misdiagnosis due to its resemblance, at an initial radiological assessment, to malignant renal cancers with a completely different prognosis and medical treatment. Unfortunately, percutaneous renal biopsy is not frequently performed due to the possible side effects related to the procedure. Therefore, the majority of oncocytoma are diagnosed after the surgical operation via partial or radical nephrectomy. For this reason, new reliable strategies to solve this issue are needed. In our review, we will discuss the clinical implications of renal oncocytoma in daily clinical practice with a particular focus on the medical diagnosis and treatment and on the potential of novel promising molecular biomarkers such as circulating microRNAs to distinguish between a benign and a malignant lesion.

External Validation of a Novel Comprehensive Trifecta System in Predicting Oncologic and Functional Outcomes of Partial Nephrectomy: Results of a Multicentric Series

Background: To validate a novel trifecta for evaluating outcomes of partial nephrectomy (PN) on a multicentric dataset. Methods: Between 2007 and 2020, three renal cancer databases were queried for patients with solitary renal masses who underwent PN (n = 649). Trifecta was estimated for overall cohort and contributing centers. Overall survival (OS), cancer-specific survival (CSS) and end-stage renal disease (ESRD) probabilities were assessed by Kaplan–Meier. Cox regression was used to identify predictors of OS, CSS, ESRD. For all analyses, a p < 0.05 was considered significant. Results: At a median follow-up of 22.7 months (IQR 12.5–76.5) overall trifecta was 76.7% [Centre A; (n = 230; 68.6%), B (n = 68; 77.3%), C (n = 200; 88.4%); p = 0.001). On Kaplan–Meier, patients achieving trifecta exhibited higher OS (p = 0.024), higher CSS (p = 0.015) and lower ESRD rates (p = 0.024). On multivariable analysis, age (HR 1.04; 95% CI 1.01–1.08) and trifecta (HR 0.34; 95% CI 0.15–0.76) were independent predictors of OS while pT stage (HR 1.95; 95% CI 0.45–8.43) and trifecta (HR 0.33; 95% CI 0.16–0.67) were predictors of CSS (each p < 0.01). Preoperative CKD stage ≥ 3a (HR 13.1; 95% CI 4.07–42.6) and trifecta (HR 0.41; 95% CI 0.19–0.87) were independent predictors of ESRD (each p < 0.05). Conclusions: On external validation, trifecta was an independent predictor of all PN endpoints, regardless of hilar control and ischemia duration.

Acute Kidney Injury at Hospital Admission for SARS-CoV-2 Infection as a Marker of Poor Prognosis: Clinical Implications for Triage Risk Stratification

BACKGROUND/AIMS

The new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a wide spectrum of effects, including acute kidney injury (AKI) in up to 40% of hospitalized patients. Given the established relationship between AKI and poor prognosis, whether AKI might be a prognostic indicator for patients admitted to the hospital for SARS-CoV-2 infection would allow for a straightforward risk stratification of these patients.

METHODS

We analyzed data of 623 patients admitted to San Raffaele Hospital (Milan, IT) between February 25 and April 19, 2020, for laboratory-confirmed SARS-CoV-2 infection. Incidence of AKI at hospital admission was calculated, with AKI defined according to the KDIGO criteria. Multivariable Cox regression models assessed the association between AKI and overall mortality and admission to the intensive care unit (ICU).

RESULTS

Overall, 108 (17%) patients had AKI at hospital admission for SARS-CoV-2 infection. After a median follow-up for survivors of 14 days (interquartile range: 8, 23), 123 patients died, while 84 patients were admitted to the ICU. After adjusting for confounders, patients who had AKI at hospital admission were at increased risk of overall mortality compared to those who did not have AKI (hazards ratio [HR]: 2.00; p = 0.0004), whereas we did not find evidence of an association between AKI and ICU admission (HR: 0.95; p = 0.9).

CONCLUSIONS

These data suggest that AKI might be an indicator of poor prognosis for patients with SARS-CoV-2 infection, and as such, given its readily availability, it might be used to improve risk stratification at hospital admission.

Perioperative anemia predicts kidney injury after partial nephrectomy

Purpose

Partial nephrectomy (PN) induced kidney injury is still a challenging clinical matter that has not been completely conquered. This study aimed to explore the influences of perioperative anemia on renal function after PN.

Materials and Methods

A total of 114 patients undergoing PN were retrospectively studied. Serum creatinine was tested preoperatively and 24 hours and 3 days after PN to evaluate the occurrence of acute kidney injury (AKI). Perioperative anemia was evaluated on the basis of the hemoglobin (Hb) value at 24 hours and 3 days postoperation. Patients were then followed up for the development of chronic kidney disease (CKD). Associations between perioperative anemia and postoperative AKI and CKD were determined.

Results

The cumulative incidence of perioperative anemia was 33.33% in the study. A total of 32.46% of patients suffered from postoperative AKI, and 16.67% of patients progressed to CKD. The incidences of AKI and CKD in perioperative anemia patients were dramatically exceeded in those without anemia. Further statistical analyses indicated that perioperative anemia was a relevant factor for postoperative kidney injury, presenting the highest odds ratio of 31.272 for postoperative AKI and 17.179 for postoperative CKD. Receiver operating characteristic curve analysis showed that ΔHb=(preoperative Hb)-(postoperative Hb nadir) was a meaningful predictor of postoperative kidney injury, with an area under the curve of 0.784 for predicting postoperative AKI and 0.805 for postoperative CKD.

Conclusions

Perioperative anemia can predict kidney injury after PN, and ΔHb shows a meaningful predictive value for postoperative AKI and CKD.

Association between Ureteral Clamping Time and Acute Kidney Injury during Robot-Assisted Radical Cystectomy

Robot-assisted radical cystectomy (RARC) is replacing open radical cystectomy (ORC) and requires clamping of the ureters, resulting in a predisposition to postrenal acute kidney injury (AKI). We investigated the association between ureteral clamping or its duration and acute/chronic postoperative kidney function. Patients who underwent radical cystectomy (robotic or open) at two tertiary institutions during 2002-2021 were retrospectively enrolled. In those who underwent RARC, the maximum postoperative percentage serum creatinine level (%sCre) change was plotted against ureteral clamping duration. They were divided into two groups using the median clamping time (210 min), and the maximum %sCre change and percentage estimated glomerular filtration rate (%eGFR) change at 3-6 months (chronic) were compared between the ORC (no clamp), RARC < 210, and RARC ≥ 210 groups. In 44 RARC patients, a weak correlation was observed between the duration of ureteral clamping and %Cre change (R2 = 0.22, p = 0.001). Baseline serum creatinine levels were comparable between the groups. However, %sCre change was significantly larger in the RARC ≥ 210 group (N = 17, +32.1%) than those in the RARC < 210 (N = 27, +6.1%) and ORC (N = 76, +9.5%) groups (both, p < 0.001). Chronic %eGFR change was comparable between the groups. Longer clamping of the ureter during RARC may precipitate AKI; therefore, the clamping duration should be minimized.

Predicting factors of acute kidney injury after partial nephrectomy and its impact on long-term renal function: A multicentre study of the Turkish Urooncology Association

OBJECTIVES

To investigate the predictors of acute kidney injury (AKI) after partial nephrectomy and the impact of AKI stage on long-term kidney function.

METHODS

Data of 1055 patients who underwent partial nephrectomy between January 2008 and January 2018 at seven separate tertiary centres were analysed. AKI was defined according to AKI Network criteria. The association between pre-operative and perioperative factors and AKI was evaluated using logistic regression analysis. Recovery of at least 90% of baseline glomerular filtration rate 1 year after partial nephrectomy, change of 1 year glomerular filtration rate compared with baseline glomerular filtration rate and stage ≥3 chronic kidney disease (CKD) progression were assessed according to the stage of AKI.

RESULTS

AKI was recorded in 281 (26.7%) of 1055 patients after partial nephrectomy, and of these patients, 197 (70.1%) had stage 1, 77 (27.4%) had stage 2 and 7 (2.5%) had stage 3. Higher tumour complexity and baseline glomerular filtration rate were independent predictors for AKI. The proportion of recovering 90% of baseline glomerular filtration rate at 1 year for any patient who had stage ≤1 vs stage 2-3 of AKI was 78.2% (95% CI: 73.2%-83.7%) and 23.8% (95% CI: 14.7%-38.7%), respectively (P < .001). The risk of stage ≥3 CKD progression for any patient who had stage ≤1 vs stage 2-3 of AKI was 6.2% (95% CI: 4.1%-9.2%) and 63.1% (95% CI: 52.5%-75.6%), respectively (P < .001).

CONCLUSIONS

AKI adversely affects renal function in the long-term after partial nephrectomy and stage 2-3 significantly increases the risk of CKD in the long term.

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.

A Nomogram for the Prediction of Intermediate Significant Renal Function Loss After Robot-assisted Partial Nephrectomy for Localized Renal Tumors: A Prospective Multicenter Observational Study (RECORd2 Project)

BACKGROUND

Robot-assisted partial nephrectomy (RAPN) is increasingly adopted for the treatment of localized renal tumors; however, rates and predictors of significant renal function (RF) loss after RAPN are still poorly investigated, especially at a long-term evaluation.

OBJECTIVE

To analyze the predictive factors and develop a clinical nomogram for predicting the likelihood of ultimate RF loss after RAPN.

DESIGN, SETTING, AND PARTICIPANTS

We prospectively evaluated all patients treated with RAPN in a multicenter series (RECORd2 project).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Significant RF loss was defined as >25% reduction in estimated glomerular filtration rate (eGFR) from preoperative assessment at 48th month follow-up after surgery. Uni- and multivariable logistic regression analyses for RF loss were performed. The area under the receiving operator characteristic curve (AUC) was used to quantify predictive discrimination. A nomogram was created from the multivariable model.

RESULTS AND LIMITATIONS

A total of 981 patients were included. The median age at surgery was 64.2 (interquartile range [IQR] 54.3-71.4) yr, and 62.4% of patients were male. The median Charlson Comorbidity Index (CCI) was 1 (IQR 0-2), 12.9% of patients suffered from diabetes mellitus, and 18.6% of patients showed peripheral vascular disease (PVD). The median Preoperative Aspects and Dimensions Used for an Anatomical (PADUA) score was 7 (IQR 7-9). Imperative indications to partial nephrectomy were present in 3.6% of patients. Significant RF loss at 48th month postoperative evaluation was registered in 108 (11%) patients. At multivariable analysis, age (p = 0.04), female gender (p < 0.0001), CCI (p < 0.0001), CCI (p < 0.0001), diabetes (p < 0.0001), PVD (p < 0.0001), eGFR (p = 0.02), imperative (p = 0.001) surgical indication, and PADUA score (p < 0.0001) were found to be predictors of RF loss. The developed nomogram including these variables showed an AUC of 0.816.

CONCLUSIONS

We developed a clinical nomogram for the prediction of late RF loss after RAPN using preoperative and surgical variables from a large multicenter dataset.

PATIENT SUMMARY

We developed a nomogram that could represent a clinical tool for early detection of patients at the highest risk of significant renal function impairment after robotic conservative surgery for renal tumors.

Usefulness of the mayo adhesive probability score as a predictive factor for renal function deterioration after partial nephrectomy: a retrospective case-control study

PURPOSE

Whether the Mayo adhesive probability score, an index of the perinephric fat environment, could be a predictive factor for renal function deterioration after partial nephrectomy was investigated.

METHODS

A retrospective case-control study of 78 patients who underwent laparoscopic partial nephrectomy was performed. An estimated glomerular filtration rate preservation rate at ≤ 90% at 3 months after surgery was defined as postoperative renal function deterioration. These patients were divided into two groups (non-deterioration and deterioration groups). Patient factors including Mayo adhesive probability scores (both tumor and unaffected sides) and surgical factors were evaluated to identify the predictors for postoperative renal function deterioration. The statistical analysis used univariate and multivariate logistic regression analyses.

RESULTS

Thirty-seven (47.4%) patients had postoperative renal function deterioration after partial nephrectomy. Univariate analysis identified Mayo adhesive probability score on the unaffected side (p = 0.02), and warm ischemia time (p < 0.01) as predictors of postoperative renal function deterioration. On multivariate analyses, Mayo adhesive probability score on the unaffected side (odds ratio: 1.38 [1.05-1.79], p = 0.02) and warm ischemia time (odds ratio: 1.04 [1.01-1.07], p < 0.01) were significantly associated with postoperative renal function deterioration as same as univariate analysis. On receive operating characteristic curve analysis, Mayo adhesive probability score on the unaffected side (cutoff value 1.5; p = 0.02) and warm ischemia time (cutoff value 26.5 min; p = 0.01) were significant predictors of renal function deterioration 3 month after surgery.

CONCLUSION

The Mayo adhesive probability score on the unaffected side and warm ischemia time are useful predictors for renal function deterioration after partial nephrectomy.

TRIAL REGISTRATION NUMBER

2019-249, January 21st, 2019, retrospectively registered.

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.

Predicting the risk of postoperative acute kidney injury: development and assessment of a novel predictive nomogram

OBJECTIVE

This study aimed to establish and internally verify the risk nomogram of postoperative acute kidney injury (AKI) in patients with renal cell carcinoma.

METHODS

We retrospectively collected data from 559 patients with renal cell carcinoma from June 2016 to May 2019 and established a prediction model. Twenty-six clinical variables were examined by least absolute shrinkage and selection operator regression analysis, and variables related to postoperative AKI were determined. The prediction model was established by multiple logistic regression analysis. Decision curve analysis was conducted to evaluate the nomogram.

RESULTS

Independent predictors of postoperative AKI were smoking, hypertension, surgical time, blood glucose, blood uric acid, alanine aminotransferase, estimated glomerular filtration rate, and radical nephrectomy. The C index of the nomogram was 0.825 (0.790-0.860) and 0.814 was still obtained in the internal validation. The nomogram had better clinical benefit when the intervention was decided at the threshold probabilities of >4% and <79% for patients and doctors, respectively.

CONCLUSIONS

This novel postoperative AKI nomogram incorporating smoking, hypertension, the surgical time, blood glucose, blood uric acid, alanine aminotransferase, the estimated glomerular filtration rate, and radical nephrectomy is convenient for facilitating the individual postoperative risk prediction of AKI in patients with renal cell carcinoma.

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.

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.

Assessment of surgical outcomes of off-clamp open partial nephrectomy without renorrhaphy for ≥T1b renal tumours

PURPOSE

To assess the surgical outcomes of off-clamp open partial nephrectomy without renorrhaphy. In the era of robot-assisted surgeries, open partial nephrectomy remains a surgical option for  ≥ T1b renal tumours. Although the necessity of renal pedicle clamping and renorrhaphy in open partial nephrectomy for larger tumours remains to be discussed, reports on this issue are rare.

METHODS

Twenty-seven open partial nephrectomies for  ≥ T1b renal tumours were performed without renal pedicle clamping or renorrhaphy. A soft coagulation system was used to control bleeding from the resection bed. Surgical results, complications, and predictors of perioperative estimated glomerular filtration rate (eGFR) preservation at 1 month and 3 months after surgery were analysed.

RESULTS

The median estimated volume of blood loss was 420 mL. The rates of perioperative eGFR preservation were 88.9 and 87.3% at 1 and 3 months after surgery, respectively. Tumour size was an independent predictor of perioperative eGFR preservation at 1 month after surgery, whereas age and exophytic/endophytic properties of the tumour were independent predictors of perioperative eGFR preservation at 3 months after surgery.

CONCLUSION

Open partial nephrectomy without renal pedicle clamping or renorrhaphy could be safely performed for  ≥ T1b renal tumours, even when tumours were entirely endophytic and located close to the renal pedicle. Mild perioperative eGFR reduction was observed. Although surgical indications should be carefully considered in these cases, off-clamp open partial nephrectomy without renorrhaphy is a feasible procedure for patients with  ≥ T1b renal tumours.

Urinary exosomal CD26 is associated with recovery from acute kidney injury in intensive care units: a prospective cohort study

OBJECTIVES

Currently there is no validated method to predict renal reversal and recovery after acute kidney injury (AKI). As exosomes have the potential for AKI prognosis and CD26 is involved in the mechanisms in AKI, this study aims to investigate whether urinary exosomal CD26 is associated with renal-related outcomes and explore its prospect as a novel prognosis biomarker.

METHODS

This was a single-center, prospective cohort study. A total of 133 AKI patients and 68 non-AKI patients admitted to ICU in Qilu Hospital Shandong University from January 2017 to January 2018. Urine samples were collected at enrollment and the relative expression of CD26 (CD26 percentage) in urinary exosomes was examined, that was then categorized into a low-CD26 level and a high-CD26 level.

RESULTS

CD26 percentage was significantly lower in the AKI cohort than in the control cohort. Within the AKI cohort, a high-CD26 level was associated with lower incidence of major adverse kidney events within 90 days, but higher incidence of reversal within 28 days. In AKI survivors, a high-CD26 level had a 4.67-, 3.50- and 4.66-fold higher odds than a low-CD26 level for early reversal, recovery and reversal, respectively, after adjustment for clinical factors. Prediction performance was moderate for AKI survivors but improved for non-septic AKI survivors.

CONCLUSIONS

Urinary exosomal CD26 is associated with renal reversal and recovery from AKI and is thus a promising prognosis biomarker.

Severity and Duration of Acute Kidney Injury and Chronic Kidney Disease after Cardiac Surgery

We aimed to evaluate whether the duration and stage of acute kidney injury (AKI) are associated with the occurrence of chronic kidney disease (CKD) in patients undergoing cardiac or thoracic aortic surgery. A total of 2009 cases were reviewed. The patients with postoperative AKI stage 1 and higher stage were divided into transient (serum creatinine elevation ≤48 h) or persistent (>48 h) AKI, respectively. Estimated glomerular filtration rate (eGFR) values during three years after surgery were collected. Occurrence of new-onset CKD stage 3 or higher or all-cause mortality was determined as the primary outcome. Multivariable Cox regression and Kaplan-Meier survival analysis were performed. The Median follow-up of renal function after surgery was 32 months. The cumulative incidences of our primary outcome at one, two, and three years after surgery were 19.8, 23.7, and 26.1%. There was a graded significant association of AKI with new-onset CKD during three years after surgery, except for transient stage 1 AKI (persistent stage 1: HR 3.11, 95% CI 2.62-4.91; transient higher stage: HR 4.07, 95% CI 2.98-6.11; persistent higher stage: HR 13.36, 95% CI 8.22-18.72). There was a significant difference in survival between transient and persistent AKI at the same stage. During three years after cardiac surgery, there was a significant and graded association between AKI stages and the development of new-onset CKD, except for transient stage 1 AKI. This association was stronger when AKI lasted more than 48 h at the same stage. Both duration and severity of AKI provide prognostic value to predict the development of CKD.

Selective Suturing or Sutureless Technique in Robot-assisted Partial Nephrectomy: Results from a Propensity-score Matched Analysis

BACKGROUND

Despite efforts aimed at preserving renal function, the functional decline after robot-assisted partial nephrectomy (RAPN) is not negligible. To address the risk of intraparenchymal vessel injuries during renorrhaphy, with consequent loss of functional renal parenchyma, we introduced a new surgical technique for RAPN.

OBJECTIVE

To compare perioperative patient outcomes between selective-suturing or sutureless RAPN (suRAPN) and standard RAPN (stRAPN).

DESIGN, SETTING, AND PARTICIPANTS

Ninety-two consecutive patients undergoing RAPN for a renal mass performed by a high-volume surgeon at a European tertiary center were included. Propensity-score matching was used to account for baseline differences between suRAPN and stRAPN patients.

INTERVENTION

RAPN using a selective-suturing or sutureless technique versus standard RAPN.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Perioperative outcomes included operative time, blood loss, length of stay, and intraoperative and 30-d postoperative complications. We also evaluated trifecta achievement (warm ischemia time ≤25 min, negative surgical margins, and no perioperative complications) and the incidence of postoperative acute kidney injury (AKI). We applied χ² tests, t tests, and Kruskal-Wallis tests to assess differences in perioperative outcomes between suRAPN and stRAPN.

RESULTS AND LIMITATIONS

Overall, 29 patients (31%) were treated with suRAPN. Only one suRAPN patient experienced intraoperative complications (p = 0.9). Two suRAPN patients (6.9%) and four stRAPN patients (13.8%) experienced 30-d postoperative complications (p = 0.3). Operative time (110 vs 150 min; p < 0.01) and length of stay (2 vs 3 d; p = 0.02) were shorter for suRAPN than for stRAPN. The trifecta outcome was achieved in 25 suRAPN patients (86%) and 20 stRAPN patients (70%; p = 0.1). Only one suRAPN patient (3.4%) versus five stRAPN patients (17%) experienced postoperative AKI (p = 0.2). Finally, the decrease in the estimated glomerular filtration rate at 6-mo follow-up was lower in the suRAPN (-5.2%) than in the stRAPN group (-9.1%; p < 0.01). Lack of randomization represents the main study limitation.

CONCLUSIONS

A selective-suturing or sutureless technique in RAPN is feasible and safe. Moreover, suRAPN is a lower-impact surgical procedure. We obtained promising results for trifecta and functional outcomes, but prospective randomized trials are needed to validate the impact of selective suturing or a sutureless technique on long-term functional outcomes.

PATIENT SUMMARY

We assessed a new technique in robotic surgery to remove part of the kidney because of kidney cancer. Our new technique involves selective suturing or no suturing of the area from where the tumor is removed. We found that the rate of complications did not increase and the operating time and length of hospital stay were shorter using this new technique.

Impact of goal-directed hemodynamic management on the incidence of acute kidney injury in patients undergoing partial nephrectomy: a pilot randomized controlled trial

Background

The incidence of acute kidney injury (AKI) remains high after partial nephrectomy. Ischemia-reperfusion injury produced by renal hilum clamping during surgery might have contributed to the development of AKI. In this study we tested the hypothesis that goal-directed fluid and blood pressure management may reduce AKI in patients following partial nephrectomy.

Methods

This was a pilot randomized controlled trial. Adult patients who were scheduled to undergo partial nephrectomy were randomized into two groups. In the intervention group, goal-directed hemodynamic management was performed from renal hilum clamping until end of surgery; the target was to maintain stroke volume variation < 6%, cardiac index 3.0–4.0 L/min/m² and mean arterial pressure > 95 mmHg with crystalloid fluids and infusion of dobutamine and/or norepinephrine. In the control group, hemodynamic management was performed according to routine practice. The primary outcome was the incidence of AKI within the first 3 postoperative days.

Results

From June 2016 to January 2017, 144 patients were enrolled and randomized (intervention group, n = 72; control group, n = 72). AKI developed in 12.5% of patients in the intervention group and in 20.8% of patients in the control group; the relative reduction of AKI was 39.9% in the intervention group but the difference was not statistically significant (relative risk 0.60, 95% confidence interval [CI] 0.28–1.28; P = 0.180). No significant differences were found regarding AKI classification, change of estimated glomerular filtration rate over time, incidence of postoperative 30-day complications, postoperative length of hospital stay, as well as 30-day and 6-month mortality between the two groups.

Conclusion

For patients undergoing partial nephrectomy, goal-directed circulatory management during surgery reduced postoperative AKI by about 40%, although not significantly so. The trial was underpowered. Large sample size randomized trials are needed to confirm our results.

Trial registration

Clinicaltrials.gov identifier: NCT02803372. Date of registration: June 6, 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01288-8.

Clinical advantages of robot-assisted partial nephrectomy versus laparoscopic partial nephrectomy in terms of global and split renal functions: A propensity score-matched comparative analysis

OBJECTIVES

To identify predictors of renal function preservation, and to compare the global and split renal function outcomes of robot-assisted partial nephrectomy and laparoscopic partial nephrectomy.

METHODS

Demographic, operative and pathological data, as well as renal function outcomes, of 251 patients who underwent laparoscopic (n = 104) and robot-assisted (n = 147) partial nephrectomy between 2008 and 2018 were retrospectively analyzed. Propensity score matching (1:1) was carried out to adjust for potential baseline confounders. Functional outcomes were assessed based on the estimated glomerular filtration rate and dynamic renal scintigraphy (using ^99m Tc-mercaptoacetyltriglycine), including renal volumetric analysis.

RESULTS

A total of 98 patients were allocated to each partial nephrectomy group. Ischemic (laparoscopic vs robot-assisted partial nephrectomy: 29 vs 15 min, P < 0.001) and operative times (181 vs 100 min, P < 0.001) were shorter in robot-assisted partial nephrectomy. The preservation ratio of global renal function at 3 months (88.3% vs 91.4%, P = 0.040) and 12 months (87.8% vs 91.5%, P = 0.010) postoperatively, and the renal function of the operated kidney (80.3% vs 88.2%, P < 0.001) were greater after robot-assisted partial nephrectomy. In robot-assisted partial nephrectomy, the volume of resected parenchyma was significantly smaller (27.2 vs 15.5 mL, P < 0.001), resulting in greater postoperative normal parenchymal volumes (120 vs 132 mL, P < 0.001) and a greater parenchymal preservation ratio (81.1% vs 90.1%, P < 0.001). The parenchymal preservation ratio was the strongest predictor of renal function preservation after surgery (P < 0.001, odds ratio 6.02).

CONCLUSIONS

Robot-assisted partial nephrectomy allows better preservation of split renal function than laparoscopic partial nephrectomy by increasing the parenchymal preservation ratio. This translates into better postoperative global renal function.

Impact of postoperative acute kidney injury on predicting the upstaging of chronic kidney disease after robot-assisted partial nephrectomy

INTRODUCTION

The aim of our study was to assess the impact of acute kidney injury (AKI) on postoperative upstaging of chronic kidney disease (CKD) after robot-assisted partial nephrectomy (RAPN).

METHODS

This study consisted of 110 patients who had undergone RAPN and were followed up for at least 6 months after surgery. Patients were classified as AKI or non-AKI based on their serum creatinine level and estimated glomerular filtration rate within 7 days after surgery. Patient characteristics, outcome of RAPN and estimated glomerular filtration rate, and CKD upstage 6 months after surgery were compared between the AKI and non-AKI groups.

RESULTS

A total of 26 patients (23.6%) experienced AKI after surgery. RENAL (radius, exophytic/endophitic properties, nearness of the tumor to the collecting system or sinus, anterior/posterior, location relative to the polar lines) nephrometry scores were ≥7 for 22 (84.6%) in the AKI group and 39 (46.4%) in the non-AKI group (P = .0006). A significantly smaller proportion of patients in the AKI group than in the non-AKI group recovered 90% of baseline function (38.5% vs 81.0%, P < .0001). CKD upstaging occurred in a total of 27 patients 24.5%) and in a significantly larger proportion of patients in the AKI group than in the non-AKI group (42.3% vs 19.0%, P = .0160). There was no significant difference in characteristics and perioperative outcomes between the patients with and without CKD, except for in those experiencing AKI.

CONCLUSION

After RAPN, AKI can be associated with CKD upstaging.

Postoperative acute kidney injury in adult non-cardiac surgery: joint consensus report of the Acute Disease Quality Initiative and PeriOperative Quality Initiative

Postoperative acute kidney injury (PO-AKI) is a common complication of major surgery that is strongly associated with short-term surgical complications and long-term adverse outcomes, including increased risk of chronic kidney disease, cardiovascular events and death. Risk factors for PO-AKI include older age and comorbid diseases such as chronic kidney disease and diabetes mellitus. PO-AKI is best defined as AKI occurring within 7 days of an operative intervention using the Kidney Disease Improving Global Outcomes (KDIGO) definition of AKI; however, additional prognostic information may be gained from detailed clinical assessment and other diagnostic investigations in the form of a focused kidney health assessment (KHA). Prevention of PO-AKI is largely based on identification of high baseline risk, monitoring and reduction of nephrotoxic insults, whereas treatment involves the application of a bundle of interventions to avoid secondary kidney injury and mitigate the severity of AKI. As PO-AKI is strongly associated with long-term adverse outcomes, some form of follow-up KHA is essential; however, the form and location of this will be dictated by the nature and severity of the AKI. In this Consensus Statement, we provide graded recommendations for AKI after non-cardiac surgery and highlight priorities for future research.