What Happens to the Preserved Renal Parenchyma After Clamped Partial Nephrectomy?

Quantifying preserved renal volume and function in patients undergoing standard partial nephrectomy vs. tumor enucleation for localized renal tumors

INTRODUCTION

Renal parenchymal volume loss from standard partial nephrectomy (SPN) is a significant prognosticator for postoperative renal function. Tumor enucleation (TE) minimizes parenchymal loss compared to SPN. Little is known regarding discrete changes in renal function associated with volume loss. We sought to quantify the differences between SPN and TE in preserving parenchymal volume and estimated glomerular filtration rate (eGFR).

METHODS

We identified 420 patients who underwent robotic partial nephrectomy (SPN or TE) at our tertiary care center from 2009 to 2022. Parenchymal volumes were calculated using TeraRecon 3D reconstruction software from axial imaging performed preoperatively and within 6 months postoperatively. Renal volume preserved and renal function were evaluated with multivariable linear and logistic regression models.

RESULTS

At 1 year, eGFR was 7% lower in patients undergoing SPN compared to TE (P < 0.01). Across both SPN and TE, only volume of preserved parenchyma was predictive of eGFR and chronic kidney disease (CKD) progression (both P < 0.01). TE preserved more healthy parenchymal volume compared to SPN (median percentage 97.6% vs 89.2%; P < 0.001). Each 1% of volumetric loss corresponded to a 0.35% decrease in eGFR at 1 year postoperatively (P < 0.01).

CONCLUSIONS

Volume of preserved renal parenchyma was the strongest factor associated with preserved eGFR and reduced odds of CKD progression. TE preserved more parenchyma than SPN, which translated to higher eGFR preservation at 1 year postoperatively.

Comparison of the perioperative outcomes of robot-assisted laparoscopic transperitoneal versus retraperitoneal partial nephrectomy for posterior-lateral renal tumors: a systematic review and meta-analysis

The study aims to assess the available literature and compare the perioperative outcomes of robotic-assisted partial nephrectomy (RAPN) for posterior-lateral renal tumors using transperitoneal (TP) and retroperitoneal (RP) approaches. Systematically searched the Embase, PubMed, and Cochrane Library databases for literature. Eligible studies were those that compared TP-RAPN and RP-RAPN for posterior-lateral renal tumors. The data from the included studies were analyzed and summarized using Review Manager 5.3, which involved comparing baseline patient and tumor characteristics, intraoperative and postoperative outcomes, and oncological outcomes. The analysis included five studies meeting the inclusion criteria, with a total of 1440 patients (814 undergoing RP-RAPN and 626 undergoing TP-RAPN). Both groups showed no significant differences in age, gender, BMI, R.E.N.A.L. score, and tumor size. Notably, compared to TP-RAPN, the RP-RAPN group demonstrated shorter operative time (OT) (MD: 17.25, P = 0.01), length of hospital stay (LOS) (MD: 0.37, P < 0.01), and lower estimated blood loss (EBL) (MD: 15.29, P < 0.01). However, no significant differences were found between the two groups in terms of warm ischemia time (WIT) (MD: -0.34, P = 0.69), overall complications (RR: 1.25, P = 0.09), major complications (the Clavien-Dindo classification ≥ 3) (RR: 0.97, P = 0.93), and positive surgical margin (PSM) (RR: 1.06, P = 0.87). The systematic review and meta-analysis suggests RP-RAPN may be more advantageous for posterior-lateral renal tumors in terms of OT, EBL, and LOS, but no significant differences were found in WIT, overall complications, major complications, and PSM. Both surgical approaches are safe, but a definitive advantage remains uncertain.

Serum uric acid level is associated with glomerular ischemic lesions in patients with primary membranous nephropathy: an analytical, cross-sectional study

To investigate the relationship between serum uric acid level and glomerular ischemic lesions (GIL) in patients with primary membranous nephropathy (PMN) and identify relevant risk factors. A total of 201 patients with PMN but normal renal function confirmed by renal biopsy executed in the Liaocheng People's Hospital, China, during January 2020-January 2023 were analyzed retrospectively. The enrolled patients were divided into a hyperuricemia group and a normal serum uric acid group (control group) according to their serum uric acid levels. Then, the participants were further divided into a non-GIL group or a GIL group based on the patient's renal biopsy results. The two groups' clinical and pathological data and meaningful indicators for differences were analyzed by binary logistic regression analysis. Additionally, the serum uric acid level prediction value on GIL was investigated using receiver operating characteristic (ROC) curves. Compared with the control group, the hyperuricemia group exhibited high serum uric acid, the prevalence of GIL, serum albumin, the prevalence of hypertension, and low-density lipoprotein cholesterol (LDL) levels (P < 0.05). Compared with the non-GIL group, the GIL group exhibited were older, had enhanced serum uric acid, serum albumin, and an increased prevalence of tubular atrophy/interstitial fibrosis (TA/IF), arteriolosclerosis, and low eGFR levels (P < 0.05). The binary logistic regression analysis revealed that the serum uric acid and the TA/IF are independent risk factors of GIL (P < 0.05). The AUC of ROC of GIL of PMN patients, predicted based on the serum uric acid concentration, was 0.736 (P < 0.05), wherein the threshold = 426.5 μmol/L and the Youden's index = 0.41. Serum uric acid concentration and the TA/IF are independent risk factors of GIL in patients with PMN, and the former exhibits prediction value on GIL in patients with PMN.

Longitudinal changes in renal parenchymal volume and function status after partial nephrectomy: a retrospective cohort study

BACKGROUND

The ipsilateral renal parenchymal volume (RPV) experiences a sharp decrease shortly after partial nephrectomy (PN), mainly due to surgical remove or devascularization of kidney tissue. However, the subsequent change of RPV and its association with glomerular filtration rate (GFR) fast decline remains unknown. Our objective was to investigate the change of ipsilateral RPV and renal function status from new baseline (1-12 months after PN) to latest follow-up (≥1 year) after PN, and to explore factors associated with ipsilateral RPV decrease rate and correlation between RPV decrease and GFR fast decline.

MATERIALS AND METHODS

A retrospective review of 367 patients with PN was conducted. Three-dimensional reconstruction of computed tomography (CT)/MRI images was performed for RPV calculation. Spectrum score was used to assess the degree of acute kidney injury (AKI) in the operated kidney after PN. GFR decline greater than 3 ml/min/1.73 m 2 /year was defined as GFR fast decline. One hundred fourteen patients underwent abdominal surgery was used as control. Predictive factors for subsequent decrease of RPV rate and GFR fast decline were evaluated by linear and logistic regression, respectively.

RESULTS

With a median interval time of 21.1 (interquartile range:13.8-35.5) months, median ipsilateral RPV significantly decreased from 118.7 (interquartile range:100.7-137.1) ml at new baseline to 111.8 (IQR: 92.3-131.3) ml at latest follow-up. The interval time [β: 1.36(0.71-2.01), P <0.001] and spectrum score [β: 5.83 (2.92-8.74), P <0.001] were identified as independent predictors of ipsilateral RPV decrease rate. GFR fast decline was observed in 101 (27.5%) patients. Annual ipsilateral RPV decrease rate [odds ratio:1.67 (1.05-2.67), P =0.03] and overweight [odds ratio:1.63 (1.02-2.60), P =0.04] were independent predictors of GFR fast decline.

CONCLUSIONS

Ipsilateral RPV experienced a moderate but significant decrease during follow-up after PN, especially in those with severer acute kidney injury. The presence of GFR fast decline was found to be associated with reduction of ipsilateral RPV, particularly in overweight individuals.

Randomized Controlled Feasibility Trial of Robot-assisted Versus Conventional Open Partial Nephrectomy: The ROBOCOP II Study

BACKGROUND

There is no evidence from randomized controlled trials (RCTs) comparing robot-assisted partial nephrectomy (RAPN) and open partial nephrectomy (OPN).

OBJECTIVE

To assess the feasibility of trial recruitment and to compare surgical outcomes between RAPN and OPN.

DESIGN, SETTING, AND PARTICIPANTS

ROBOCOP II was designed as single-center, open-label, feasibility RCT. Patients with suspected localized renal cell carcinoma referred for PN were randomized at a 1:1 ratio to either RAPN or OPN.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was the feasibility of recruitment, assessed as the accrual rate. Secondary outcomes included perioperative and postoperative data. Data were analyzed descriptively in a modified intention-to-treat population consisting of randomized patients who underwent surgery.

RESULTS AND LIMITATIONS

A total of 50 patients underwent RAPN or OPN (accrual rate 65%). In comparison to OPN, RAPN had lower blood loss (OPN 361 ml, standard deviation [SD] 238; RAPN 149 ml, SD 122; difference 212 ml, 95% confidence interval [CI] 105-320; p < 0.001), less need for opioids (OPN 46%; RAPN 16%; difference 30%, 95% CI 5-54; p = 0.024), and fewer complications according to the mean Comprehensive Complication Index (OPN 14, SD 16; RAPN 5, SD 15; difference 9, 95% CI 0-18; p = 0.008). OPN has a shorter operative time (OPN 112 min, SD 29; RAPN 130 min, SD 32; difference -18 min, 95% CI -35 to -1; p = 0.046) and warm ischemia time (OPN 8.7 min, SD 7.1; RAPN 15.4 min, SD 7.0; difference 6.7 min, 95% CI -10.7 to -2.7; p = 0.001). There were no differences between RAPN and OPN regarding postoperative kidney function.

CONCLUSIONS

This first RCT comparing OPN and RAPN met the primary outcome of the feasibility of recruitment; however, the window for future RCTs is closing. Each approach has advantages over the other, and both remain safe and effective options.

PATIENT SUMMARY

For patients with a kidney tumor, open surgery and robot-assisted keyhole surgery are both feasible and safe approaches for partial removal of the affected kidney. Each approach has known advantages. Long-term follow-up will explore differences in quality of life and cancer control outcomes.

Transperitoneal vs. Retroperitoneal Approach in Laparoscopic Partial Nephrectomy for Posterior Renal Tumors: A Retrospective, Multi-Center, Comparative Study

Purpose: The aim of our study is to compare the perioperative, functional, and oncological outcomes of laparoscopic transperitoneal partial nephrectomy (LTPN) and laparoscopic retroperitoneal partial nephrectomy (LRPN) for posterior cT1 renal tumors. Methods: We retrospectively collected data on all patients who consecutively underwent LTPN and LRPN for posterior cT1 renal tumors in three different centers from January 2015 to January 2023. Patients with a single, unilateral, cT1 renal mass, located in the posterior renal surface were included. Patients' data regarding perioperative, functional, and oncological outcomes were collected from medical records and statistically analyzed and compared. Results: A total of 128 patients was obtained, with 53 patients in the LPTN group and 75 patients in the LRPN group. Baseline characteristics were similar. Warm ischemia time (WIT) (18.8 vs. 22.6 min, p = 0.002) and immediate postoperative eGFR drop (-6.1 vs. -13.0 mL/min/1.73 m2, p = 0.047) were significantly lower in the LPTN group. Estimated blood loss (EBL) (100 vs. 150 mL, p = 0.043) was significantly lower in the LRPN group. All other perioperative and functional outcomes and complications were similar between the groups. The positive surgical margin (PSM) rate was lower in the LRPN group, although without statistical significance (7.2% vs. 13.5%, p = 0.258). Surgical success defined by Trifecta (WIT ≤ 25 min, no PSM, and no major postoperative complication) was similar between both approaches. Conclusions: LTPN has significantly shorter WIT and a significantly smaller drop in immediate eGFR when compared to LRPN for posterior renal tumors. On the other hand, LRPN has significantly less EBL than LTPN. LRPN demonstrated fewer PSMs than LTPN, albeit without statistical significance. In terms of overall surgical success, as defined by Trifecta, both approaches achieved similar results.

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.

Comparison of the efficacy of robotic-assisted retroperitoneal laparoscopy and traditional retroperitoneal laparoscopy in partial nephrectomy among patients with renal tumors: A retrospective cohort study

PURPOSE

The efficacy of robotic-assisted retroperitoneal laparoscopy (RARL) and traditional retroperitoneal laparoscopy (TRL) in patients undergoing partial nephrectomy for treatment of a renal tumor were compared in this study.

MATERIALS AND METHODS

The retrospective study reviewed patients with renal tumors who underwent partial nephrectomy in our hospital between January 2020 and February 2022. According to different surgical methods, the patients were enrolled into the RARL (experimental group, n=65) or the TRL (control group, n=63) partial nephrectomy group.

RESULTS

One hundred twenty-eight patients were reviewed. The number of patients with collecting system injuries in the experimental group (19 cases) was significantly less than in the control group (32 cases; p<0.05). The operative time (115.7±48.2 min vs. 143.1±25.5 min) and heat ischemia time (18.7±4.9 min vs. 26.4±5.2 min) were significantly shorter in the experimental group than in the control group. The intraoperative blood loss (35.4±13.2 mL vs. 96.1±34.3 mL) and postoperative drainage volume (55.9±26.4 mL vs. 75.2±32.6 mL) were significantly less in the experimental group than in the control group (p<0.05). The change in postoperative glomerular filtration rate decrease in the experimental group was significantly lower than that in the control group (p<0.05). The change level in postoperative creatinine increase in the experimental group were significantly lower than those in the control group (p<0.05). There were no considerable differences in other clinical indicators or follow-up results between the two groups.

CONCLUSIONS

RARL was superior to TRL for renal tumor treatment with respect to operative time, intraoperative blood loss, warm ischemia time, and postoperative renal function recovery.

Can the Abdominal Aortic Atherosclerotic Plaque Index Predict Functional Outcomes after Robot-Assisted Partial Nephrectomy?

This study aims to evaluate the abdominal aortic atherosclerotic plaque index (API)'s predictive role in patients with pre-operatively or post-operatively developed chronic kidney disease (CKD) treated with robot-assisted partial nephrectomy (RAPN) for renal cell carcinoma (RCC). One hundred and eighty-three patients (134 with no pre- and post-operative CKD (no CKD) and 49 with persistent or post-operative CKD development (post-op CKD)) who underwent RAPN between January 2019 and January 2022 were deemed eligible for the analysis. The API was calculated using dedicated software by assessing the ratio between the CT scan atherosclerotic plaque volume and the abdominal aortic volume. The ROC regression model demonstrated the influence of API on CKD development, with an increasing effect according to its value (coefficient 0.13; 95% CI 0.04-0.23; p = 0.006). The Model 1 multivariable analysis of the predictors of post-op CKD found that the following are independently associated with post-op CKD: Charlson Comorbidity Index (OR 1.31; p = 0.01), last follow-up (FU) Δ%eGFR (OR 0.95; p < 0.01), and API ≥ 10 (OR 25.4; p = 0.01). Model 2 showed API ≥ 10 as the only factor associated with CKD development (OR 25.2; p = 0.04). The median follow-up was 22 months. Our results demonstrate API to be a strong predictor of post-operative CKD, allowing the surgeon to tailor the best treatment for each patient, especially in those who might be at higher risk of CKD.

Off-clamp Versus On-clamp Robot-assisted Partial Nephrectomy: A Propensity-matched Analysis

BACKGROUND

Partial nephrectomy is the preferred treatment option for the management of small renal masses. On-clamp partial nephrectomy is associated with a risk of ischemia and a greater loss of postoperative renal function, while the off-clamp procedure decreases the duration of renal ischemia, leading to better renal function preservation. However, the efficacy of the off- versus on-clamp partial nephrectomy for renal function preservation remains debatable.

OBJECTIVE

To compare perioperative and functional outcomes following off- and on-clamp robot-assisted partial nephrectomy (RAPN).

DESIGN, SETTING, AND PARTICIPANTS

This study used the prospective multinational collaborative Vattikuti Collective Quality Initiative (VCQI) database for RAPN.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary objective of this study was the comparison of perioperative and functional outcomes between patients who underwent off- and on-clamp RAPN. Propensity scores were calculated for age, sex, body mass index (BMI), renal nephrometry score (RNS) and preoperative estimated glomerular filtration rate (eGFR).

RESULTS AND LIMITATIONS

Of the 2114 patients, 210 had undergone off-clamp RAPN and others on-clamp procedure. Propensity matching was possible for 205 patients in a 1:1 ratio. After matching, the two groups were comparable for age, sex, BMI, tumor size, multifocality, tumor side, face of tumor, RNS, polar location of the tumor, surgical access, and preoperative hemoglobin, creatinine, and eGFR. There was no difference between the two groups for intraoperative (4.8% vs 5.3%, p = 0.823) and postoperative (11.2% vs 8.3%, p = 0.318) complications. Need for blood transfusion (2.9% vs 0, p = 0.030) and conversion to radical nephrectomy (10.2% vs 1%, p < 0.001) were significantly higher in the off-clamp group. At the last follow-up, there was no difference between the two groups for creatinine and eGFR. The mean fall in eGFR at the last follow-up compared with that at baseline was equivalent between the two groups (-16.0 vs -17.3 ml/min, p = 0.985).

CONCLUSIONS

Off-clamp RAPN does not result in better renal functional preservation. Alternatively, it may be associated with increased rates of conversion to radical nephrectomy and need for blood transfusion.

PATIENT SUMMARY

With this multicentric study, we noted that performing robotic partial nephrectomy without clamping the blood supply to the kidney is not associated with better preservation of renal function. However, off-clamp partial nephrectomy is associated with increased rates of conversion to radical nephrectomy and blood transfusion.

Long-term effect of acute ischemic injury on the kidney underwent clamped partial nephrectomy

GFR reaches a new baseline, primarily correlating with nephron-mass preservation, 1-12 months after partial nephrectomy (PN). However, does the ipsilateral GFR experience subsequent decline, and does acute ischemic injury has long-term effect on the operated kidney? 319 patients with two kidneys and unilateral clamped PN were analyzed. All had preoperative, new-baseline, and latest follow-up imaging/serum creatinine levels. Annual ipsilateral GFR decline rate (AIGDR) was defined as new-baseline GFR minus latest follow-up GFR normalized by new-baseline GFR, per year. Spectrum score was used to reflect the degree of acute ischemic injury in the operated kidney. 100 subjects searching for health screening served as controls. Predictive factors for AIGDR were assessed. The median AIGDR was 2.25%, significantly higher than controls (0.88%, p = 0.036). With some contralateral hypertrophy, the global annual GFR decline was similar to that of controls (0.81% vs. 0.88%, p = 0.7). Spectrum score correlated significantly with AIGDR (p = 0.037). These results support that acute ischemic injury has long-term effect on the operated kidney.

Partial versus radical nephrectomy for the treatment of pT3aN0M0 renal cell carcinoma: A propensity score analysis

BACKGROUND

The survival benefit of partial nephrectomy (PN) in pT3a RCC patients is controversial. Here we aimed to explore the potential benefit of PN for pT3aN0M0 renal cell carcinoma (RCC).

MATERIAL AND METHODS

Data of patients with pT3aN0M0 RCC who were diagnosed between 2010 and 2012 in the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) database were retrospectively collected. Overall survival (OS) and cancer specific survival (CSS) were compared using a Cox proportional hazards model between PN and radical nephrectomy (RN) in pT3aN0M0 RCC. Propensity score (-adjusted, -stratified, -weighted, and -matched) analyses were performed to control for imbalances in individual risk factors.

RESULTS

A total of 1277 patients with pT3aN0M0 RCC were identified, of whom 200 patients were treated with PN and 1077 patients were RN. PN showed favorable OS and CSS in 0-4 cm pT3aN0M0 RCC (P < 0.05), and similar OS and CSS in 4-7 cm pT3aN0M0 RCC, compared with RN using un-adjusted analyses. The Propensity score analyses further demonstrated the survival benefit of PN compared with the RN in 0-4 cm pT3aN0M0 RCC (P < 0.05).

CONCLUSIONS

In this retrospective study, PN was associated with improved survival compared with RN in 0-4 cm pT3aN0M0 RCC. Moreover, survival was comparable between PN and RN in 4-7 cm pT3aN0M0 RCC. These data provided evidence that PN could be an alternative choice for T3aN0M0 RCC less than 7 cm. Particularly, patients with 0-4 cm pT3aN0M0 RCC might benefit from PN.

Risks and benefits of partial nephrectomy performed with limited or with zero ischaemia time

OBJECTIVE

To test the hypothesis that longer warm ischaemia time (WIT) might have a marginal impact on renal functional outcomes and might, in fact, reduce haemorrhagic risk intra-operatively.

PATIENTS AND METHODS

Data from 1140 patients treated with elective partial nephrectomy (PN) for a cT1-2 cN0 cM0 renal mass were prospectively collected. WIT was defined as the duration of clamping of the main renal artery with no refrigeration and was tested as a continuous variable. The primary outcome of the study was evaluation of the effect of WIT on renal function (estimated glomerular filtration rate [eGFR]) postoperatively, at 6 months and in the long term (measured between 1 and 5 years after surgery). The secondary outcome of the study was haemorrhagic risk, defined as estimated blood loss (EBL) or peri-operative transfusions. Multivariable linear, logistic and Cox regression analyses, accounting for age, Charlson comorbidity index, clinical size, preoperative eGFR and year of surgery, were used and the potential nonlinear relationship between WIT and the study outcomes was modelled using restricted cubic splines.

RESULTS

A total of 863 patients (76%) underwent PN with WIT and 277 (24%) without. The baseline median eGFR was 87.3 (68.8-99.2) mL/min/1.73m2 for the on-clamp population and 80.6 (63.2-95.2) mL/min/1.73m2  for the off-clamp population. The median duration of WIT was 17 (13-21) min. At multivariable analyses predicting renal function, longer WIT was associated with decreased postoperative eGFR (estimate: -0.21, 95% confidence interval [CI] -0.31; -0.11 [P < 0.001]). Conversely, no association between WIT and eGFR was recorded at 6-month or long-term follow-up (all P > 0.8). At multivariable analyses predicting haemorrhagic risk, clampless resection with no ischaemia time and PN with short WIT was associated with an increased EBL (estimate: -21.56, 95% CI -28.33; -14.79 [P < 0.001]) and peri-operative transfusion rate (estimate: -0.009, 95% CI -0.01; -0.003 [P = 0.002]). No association between WIT and positive surgical margin status was recorded (all P = 0.1).

CONCLUSION

Patients and clinicians should be aware that performing PN with very limited or even with zero WIT might increase bleeding and the need for peri-operative transfusion while not improving long-term renal function outcomes.

Limited non-linear impact of warm ischemia time on renal functional decline after partial nephrectomy: a propensity score-matched study

OBJECTIVE

To quantificationally illustrate the impact of ischemia time (IT) on renal function decline after partial nephrectomy (PN), especially for patients with compromised baseline renal function (estimated glomerular filtration rate [eGFR] < 90 mL/min/1.73 m²).

METHODS

Patients undergoing PN during 2014-2021 from a prospectively maintained database were reviewed. Propensity score matching (PSM) was employed to balance the possible covariates between patients with or without baseline compromised renal function. Specifically, the relationship of IT with postoperative renal function was illustrated. Two machine learning methods (logistic least absolute shrinkage and selection operator [LASSO] logistic regression and random forest) were applied to quantify the relative impact of each covariables.

RESULTS

The average drop percent of eGFR was -10.9% (- 12.2%, - 9.0%). Multivariable Cox proportional regression and linear regression analyses identified five risk factors for renal function decline, namely RENAL Nephrometry Score (RNS), age, baseline eGFR, diabetes and IT (all p < 0.05). Specifically, the relationship of IT with postoperative functional decline emerged as non-linear, with an increase from 10-30 min and a plateau afterwards among patients with normal function (eGFR ≥ 90 mL/min/1.73 m²), whereas with an increase from 10 to 20 min and a plateau afterwards among patients with compromised function (eGFR < 90 mL/min/1.73 m²). Furthermore, the coefficient's path and random forest analysis revealed that the top two most important features were RNS and age.

CONCLUSION

IT exhibits the secondarily non-linear relationship with postoperative renal function decline. Patients with compromised baseline renal function are less tolerant to ischemia damage. The use of a single cut-off interval of IT in the setting of PN is flawed.

The role of warm ischemia time on functional outcomes after robotic partial nephrectomy: a radionuclide renal scan study from the clock randomized trial

PURPOSE

To evaluate the relationship between warm ischemia time (WIT) duration and renal function after robot-assisted partial nephrectomy (RAPN).

METHODS

The CLOCK trial is a phase 3 randomized controlled trial comparing on- vs off-clamp RAPN. All patients underwent pre- and postoperative renal scintigraphy. Six-month absolute variation of eGFR (AV-GFR), rate of relative variation in eGFR over 25% (RV-GFR > 25), absolute variation of split renal function (SRF) at scintigraphy (AV-SRF). The relationships WIT/outcomes were assessed by correlation graphs and then modeled by uni- and multivariable regression.

RESULTS

324 patients were included (206 on-clamp, 118 off-clamp RAPN). Correlation graphs showed a threshold on WIT equal to 10 min. The differences in outcome measures between cases with WIT < vs ≥ 10 min were: AV-GFR - 3.7 vs - 7.5 ml/min (p < 0.001); AV-SRF - 1% vs - 3.6% (p < 0.001); RV-GFR > 25 9.3% vs 17.8% (p = 0.008). Multivariable models found that AV-GFR was related to WIT ≥ 10 min (regression coefficient [RC] - 0.52, p = 0.019), age (RC - 0.35, p = 0.001) and baseline eGFR (RC - 0.30, p < 0.001); RV-GFR > 25 to WIT ≥ 10 min (odds ratio [OR] 1.11, p = 0.007) and acute kidney injury defined as > 50% increase in serum creatinine (OR 19.7, p = 0.009); AV-SRF to WIT ≥ 10 min (RC - 0.30, p = 0.018), baseline SRF (RC - 0.76, p < 0.001) and RENAL score (RC - 0.60. p = 0.028). The main limitation was that the CLOCK trial was designed on a different endpoint and therefore the present analysis could be underpowered.

CONCLUSIONS

Up to 10 min WIT had no consequences on functional outcomes. Above the 10-min threshold, a statistically significant, but clinically negligible impact was found.

Risk Factors of Chronic Kidney Disease after Partial Nephrectomy

Background: In comparison with radical nephrectomy, partial nephrectomy (PN) is considered a better option for small renal mass surgery, because of optimal kidney tissue removal and parenchyma preservation. But there are patients with worsening postoperative renal function (RF) and chronic kidney disease (CKD) after PN. Therefore, the study aimed to evaluate and detect risk factors for CKD after PN.Materials and Methods. A prospective observational study was conducted, which consisted of 91 individuals who received PN with warm ischemia and an estimated preoperative glomerular filtration rate (eGFR) ≥ 60 ml/min/1.72m2 without pathologic albuminuria. Preoperative and intraoperative factors like intraoperative hypotension (IOH), blood loss, and resected part volume were analyzed.Results. At 6-month follow-up, 14 (15.4 %) patients experienced postoperative CKD. After 12 months of follow-up, 15 (16.5 %) patients had CKD. Patients with CKD had a lower preoperative eGFR than non-CKD group (69.0 vs 91.0 ml/min/1.72m2, p < 0.001), longer ischemia (20.0 vs 14.0, p = 0.002) and IOH time (40.0 (40.0; 47.5) vs 0.0 (0.0; 26.2) min, p < 0.001). Also, higher volumes of resected kidney part tumor and removed parenchyma with higher glomerulosclerosis amounts (73.3 % vs 14.5 %, p = 0.009) were found in CKD group. Estimated blood loss > 500 ml during PN was discovered to be the major risk factor for CKD development (OR 11.13, 95 % CI 1.88–65.92, p = 0.008). Furthermore, kidney resected part volume (OR 1.05, 95% CI 1.05-1.10, p = 0.033) and IOH time (OR 1.11, 95% CI 1.03-1.19, p = 0.005) were identified as risk factors for postoperative CKD. Conclusions. Patients after PN are at an increased risk of CKD development. Most commonly, postoperative CKD occurs in the first 6 months after PN and appears stable after 12 months of follow-up. Blood loss > 500 ml during PN, IOH and resected kidney volume can have an impact on postoperative RF and increase the risk of CKD.