Impact of warm ischaemia time on postoperative renal function after partial nephrectomy for clinical T1 renal cell carcinoma: a propensity score-matched study

Surgical outcomes of novel retroperitoneal low anterior vs posterior and transperitoneal access in single-port partial nephrectomy

PURPOSE

Single-Port Robot-Assisted Partial Nephrectomy (SP-RAPN) can be performed by transperitoneal and retroperitoneal approaches. However, there is a lack of surgical outcomes for novel Retroperitoneal Low Anterior Access (LAA) in SP-RAPN. The study compared outcomes of the standard approach (SA), considering transperitoneal (TP) and posterior retroperitoneal (RP) access vs LAA in SP-RAPN series.

METHODS

102 consecutive patients underwent SP-RAPN between 2019 and 2023 at a tertiary referral robotic center were identified. Baseline characteristics, peri- and post-operative outcomes were collected. Patients were stratified according to surgical approach into standard (RP or TP) vs LAA and, subsequently, RP vs LAA. Multivariable logistic regression analysis was used to test the probability of the same-day discharge adjusting for comorbidity indexes.

RESULTS

Overall, 102 consecutive patients were included in this study (68 SA - 26 TP and 42 posterior RP vs 34 LAA). Median age was 60 (IQR 51.5-66) years and median BMI was 31 (IQR 26.3-37.6). No baseline differences were observed. LAA exhibited significantly shorter length of stay (LOS) (median 10 [IQR 8-12] vs 24 [IQR 12-30.2.] hours, p < .0001), reduced post-operative pain (p < .0001) and decreased narcotic use on 0-1 PO Day (p < .001) compared to SA and RP only. Multivariate analysis, adjusting for comorbidities, identified LAA as a strong predictor for Same-Day Discharge.

CONCLUSION

LAA is an effective approach as well as RP and TP, regardless of the renal mass location, whether it is anterior or posterior, upper/mid or lower pole, yielding favorable outcomes in LOS, post-operative pain and decreased narcotics use compared to SA in SP-RAPN.

Clinical application of superselective transarterial embolization of renal tumors in zero ischaemia robotic-assisted laparoscopic partial nephrectomy

Objective

To assess the feasibility and safety of zero ischaemia robotic-assisted laparoscopic partial nephrectomy (RALPN) after preoperative superselective transarterial embolization (STE) of T1 renal cancer.

Methods

We retrospectively analyzed the data of 32 patients who underwent zero ischaemia RALPN after STE and 140 patients who received standard robot-assisted laparoscopic partial nephrectomy (S-RALPN). In addition, we selected 35 patients treated with off-clamp RALPN (O-RALPN) from September 2017 to March 2022 for comparison. STE was performed by the same interventional practitioner, and zero ischaemia laparoscopic partial nephrectomy (LPN) was carried out by experienced surgeon 1-12 hours after STE. The intraoperative data and postoperative complications were recorded. The postoperative renal function, routine urine test, urinary Computed Tomography (CT), and preoperative and postoperative glomerular filtration rate (GFR) data were analyzed.

Results

All operations were completed successfully. There were no cases of conversion to opening and no deaths. The renal arterial trunk was not blocked. No blood transfusions were needed. The mean operation time was 91.5 ± 34.28 minutes. The mean blood loss was 58.59 ± 54.11 ml. No recurrence or metastasis occurred.

Conclusion

For patients with renal tumors, STE of renal tumors in zero ischaemia RALPN can preserve more renal function, and it provides a safe and feasible surgical method.

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 Impact of Postoperative Renal Function Recovery after Laparoscopic and Robot-Assisted Partial Nephrectomy in Patients with Renal Cell Carcinoma

Background and objectives: This study aimed to evaluate the association between warm ischemic time (WIT) and postoperative renal function using Trifecta achievement in patients with renal cell carcinoma (RCC) who underwent robotic (RAPN) or laparoscopic partial nephrectomy (LPN). Materials and Methods: We conducted a retrospective multicenter cohort study of patients with RCC who underwent RAPN (RAPN group) or LPN (LPN group) at three institutions in Japan between March 2012 and October 2021. The primary endpoints were the rate of trifecta achievement in both surgical techniques and the association between WIT and recovery of postoperative renal function surgical outcomes. Results: The rate of trifecta achievement was significantly lower in patients with LPN than in those with RAPN (p < 0.001). WIT ≥ 25 min were 18 patients (18%) in the RAPN group and 89 (52.7%) in the LPN group. The postoperative estimated glomerular filtration rate (eGFR) was almost the same. However, 13 patients (7.7%) had a decreased in eGFR ≥ 15% at 3 months after LPN compared with the preoperative eGFR. Conclusions: The rate of trifecta achievement in the RAPN group was significantly higher than that in the LPN group. However, eGFR was identified as relatively better preserved after PN in both groups.

Trifecta and pentafacta outcomes in laparoscopic and robotic nephron-sparing surgery for highly complex renal tumors: A propensity score-matched cohort analysis

PURPOSE

To compare the trifecta and pentafacta outcomes of laparoscopic partial nephrectomy (LPN) and robotic partial nephrectomy (RPN) in highly complex renal tumors (RENAL nephrometry score ≥10) using a matched- cohort analysis.

METHODS

Patients undergoing LPN or RPN with for renal tumors with RENAL score≥10 between January 2014 and December 2019 were matched using 1:2 propensity score match analysis based on age, body mass index (BMI), gender, laterality of tumor, RENAL score, and American Society of Anaesthesiologists (ASA) score. The two groups were compared for trifecta and pentafacta outcomes.

RESULTS

Thirty patients undergoing LPN (Group A) were matched with 60 patients undergoing RPN (Group B). The mean age (SD) was 53.7(12.9) years. The median (IQR) RENAL score was 10(10-11). In comparison, the mean WIT in Group A was significantly longer than Group B (26.2min vs 23.0min, p=0.013).The overall complication rate was 36.7% in Group A as compared to 20% in Group B (p=0.440). The trifecta outcomes could be achieved in 11 patients (36.7%) in Group A compared to 40 patients (66.7%) in Group B (p=0.012). Moreover, 10 patients (33.3%) in Group A and 28 patients (46.7%) in Group B achieved pentafacta outcomes (p=0.227).

CONCLUSIONS

In a matched cohort of patients undergoing NSS for highly complex renal tumors (RENAL score ≥10), the robotic approach offers a superior advantage in the achievement of trifecta outcomes as compared to the laparoscopic approach. However, both LPN and RPN can achieve similar pentafacta outcomes.

Limited impact of warm ischemic threshold for partial nephrectomy in the robotic surgery era: A propensity score matching study

OBJECTIVES

To evaluate the association between extended (≥30 min) warm ischemic time and renal function in patients undergoing robot-assisted partial nephrectomy.

METHODS

This multi-institutional study retrospectively recruited 1131 patients who underwent robot-assisted partial nephrectomy. Patients were classified into shorter (<30 min; n = 1038) and longer (≥30 min; n = 92) groups based on the ischemic time required, and 1:2 propensity score matching was used to minimize selection bias. The perioperative outcomes, including acute kidney injury and trifecta attainment, and mid/long-term renal function were assessed before and after matching.

RESULTS

Patients in the longer group had tumors with a significantly larger diameter and RENAL nephrometry score. The decline in the nadir of the estimated glomerular filtration rate was significantly greater in the longer than the shorter group in the unmatched and matched cohorts (-16.2 vs -5.5%, P < 0.001; 15.5 vs -9.5%, P = 0.003, respectively). A higher incidence of acute kidney injury (9.8 vs 2.6%, P = 0.002) was observed in the longer group before matching, whereas the difference was comparable after matching. Before matching, the decline in estimated glomerular filtration rate at 6 months postoperatively was greater (-8.2 vs -5.1%, P = 0.005) and trifecta attainment was lower (50.0 vs 63.5%, P < 0.001) in the longer group. However, the differences were comparable for both the parameters between the groups in the matched cohort.

CONCLUSIONS

While extended warm ischemia during robot-assisted partial nephrectomy can be demanded in case of large and complex tumors, its impact on postoperative renal function is limited.

Warm ischemia time length during on-clamp partial nephrectomy: dose it really matter?

BACKGROUND

The impact of warm ischemia time (WIT) on renal functional recovery remains controversial. We examined the length of WIT >30 min. on the long-term renal function following on-clamp partial nephrectomy (PN).

METHODS

Data from 23 centers for patients undergoing on-clamp PN between 2000 and 2018 were analyzed. We included patients with two kidneys, single tumor, cT1, minimum 1-year followup, and preoperative eGFR ≥60 ml/min/1.73m2. Patients were divided into two groups according to WIT length: group Ⅰ "WIT ≤30 min." and group Ⅱ "WIT >30 min.". A propensity-score matched analysis (1:1 match) was performed to eliminate potential confounding factors between groups. We compared eGFR values, eGFR (%) preservation, eGFR decline, events of chronic kidney disease (CKD) upgrading, and CKD-free progression rates between both groups. Cox regression analysis evaluated WIT impact on upgrading of CKD stages.

RESULTS

The primary cohort consisted of 3526 patients: group Ⅰ (n=2868) and group Ⅱ (n=658). After matching the final cohort consisted of 344 patients in each group. At last followup, there were no significant differences in median eGFR values at 1, 3, 5, and 10 years (P>0.05) between the matched groups. In addition, the median eGFR (%) preservation and absolute eGFR change were similar (89% in group Ⅰ vs. 87% in group Ⅱ, p=0.638) and (-10 in group Ⅰ vs. -11 in group Ⅱ, p=0.577), respectively. The 5 years new-onset CKD-free progression rates were comparable in the non-matched groups (79% in group Ⅰ vs. 81% in group Ⅱ, log-rank, p=0.763) and the matched groups (78.8% in group Ⅰ vs. 76.3% in group Ⅱ, log-rank, p=0.905). Univariable Cox regression analysis showed that WIT >30 min. was not a predictor of overall CKD upgrading (HR:0.953, 95%CI 0.829-1.094, p=0.764) nor upgrading into CKD stage ≥Ⅲ (HR:0.972, 95%CI 0.805-1.173, p=0.764). Retrospective design is a limitation of our study.

CONCLUSIONS

Our analysis based on a large multicenter international cohort study suggests that WIT length during PN has no effect on the long-term renal function outcomes in patients having two kidneys and preoperative eGFR ≥60 ml/min/1.73m2.

How to improve outcome in nephron-sparing surgery: the impact of new techniques

PURPOSE OF REVIEW

Nephron-sparing partial nephrectomy is the state of the art for localized small renal mass and it is gaining attention also for more advanced cases. In the present narrative review, we discuss the new developments that have occurred in the advancement of this approach over the past few years.

RECENT FINDINGS

Off-clamp, selective/superselective clamp and early-unclamping techniques are safe and feasible approaches, with potentially superior functional outcomes, and noninferior complications rate and oncological outcomes, when compared with main artery clamping. Renorrhaphy must preserve the physiological vascularization of residual parenchyma. Running sutures, particularly using barbed wires, shorten the operating and ischemia times. A further advantage could derive from avoiding a double-layer suture. Transperitoneal robot-assisted partial nephrectomy (RAPN) and retroperitoneal RAPN can be considered equivalent in terms of perioperative morbidity, functional and oncologic outcomes, regardless of tumor's location, thus the choice of the approach should be driven by the surgeon's expertise. Future improvements should be introduced by the single-port robotic surgery, which seems to be safe and feasibly also in an off-clamp manner.

SUMMARY

Significant advances have recently been achieved in nephron-sparing surgery technique. However, future studies with standardized reporting of these new techniques are needed to assess the real impact of them on early and long-term functional outcomes.

Quercetin as a nephroprotector after warm ischemia: histomorphometric evaluation in a rodent model

Purpose:

To quantitatively evaluate the possible long-term protective effects of quercetin during renal warm ischemia.

Materials and Methods:

Male rats were allocated into 4 groups: sham (S), sham quercetin (SQ), ischemia (I), and ischemia quercetin (IQ). Groups SQ and IQ received quercetin (50mg/kg) before and after surgery. Groups I and IQ had their left renal vessels clamped for 60 minutes. All animals were euthanized four weeks after the procedure, and serum urea and creatinine levels were measured. Renal weight and volume, cortex-non-cortex area ratio (C-NC), cortical volume (CV), glomerular volumetric density (Vv[glom]), volume-weighted glomerular volume (VWGV) and number of glomeruli per kidney (N[glom]) were evaluated by stereological methods. Results were considered statistically significant when p <0.05.

Results:

Serum urea levels in group I increased by 10.4% in relation to group S, but no differences were observed among the other groups. The C-NC of group I was lower than those of all other groups, and group IQ had similar results to sham groups. The Vv[glom] and N[glom] of group I were lower than those of group S (33.7% and 28.3%, respectively) and group IQ had no significant difference compared to the S group.

Conclusions:

Quercetin was effective as a nephroprotective agent in preventing the glomerular loss observed when the kidney was subjected to warm ischemia. This suggests that this flavonoid may be used preventively in kidney surgery, when warm ischemia is necessary, such as partial nephrectomy.

Three-dimensional Reconstruction of Renal Vascular Tumor Anatomy to facilitate accurate preoperative planning of partial nephrectomy

Objectives

To evaluate the role of three-dimensional (3D) reconstruction tumors and vessels of the kidneys in aiding the preoperative planning of partial nephrectomy.

Materials and methods

Patients with renal tumors to be treated with partial nephrectomy were included. Each patient underwent a preoperative computed tomography (CT) survey, and the reconstruction of each patient's 3D arteriography and 3D surface-rendered tumor was performed based on the CT images for preoperative surgical planning.

Results

A total of 6 patients, three with tumors of the right kidney and three with tumors of the left kidney, were enrolled in the study. The patients' mean age was 49.33 ± 4.03 years (range: 45-57 years), and their mean tumor size was 4.4 ± 1.84 cm (range: 2.2-6.8 cm). Four underwent robot-assisted laparoscopic partial nephrectomies, one underwent a traditional laparoscopic partial nephrectomy, and one underwent a radical nephrectomy through laparotomy. Their average postoperative hospital stay was 6.7 days (range: 3-10 days). No intraoperative or postoperative complications were noted. The renal function was preserved in all the patients, and none of the patients exhibited evidence of local recurrence during more than 6 years of follow-up.

Conclusions

3D arteriography fused with 3D surface-rendered tumor image navigation facilitates precise preoperative planning.

miR-218 Expressed in Endothelial Progenitor Cells Contributes to the Development and Repair of the Kidney Microvasculature

Ischemia due to hypoperfusion is one of the most common forms of acute kidney injury. We hypothesized that kidney hypoxia initiates the up-regulation of miR-218 expression in endothelial progenitor cells (EPCs) to guide endocapillary repair. Murine renal artery-derived EPCs (CD34+/CD105-) showed down-regulation of mmu-Mir218-5p/U6 RNA ratio after ischemic injury, while in human renal arteries, MIR218-5p expression was up-regulated after ischemic injury. MIR218 expression was clarified in cell culture experiments in which increases in both SLIT3 and MIR218-2-5p expressions were observed after 5 minutes of hypoxia. ROBO1 transcript, a downstream target of MIR218-2-5p, showed inverse expression to MIR218-2-5p. EPCs transfected with a MIR218-5p inhibitor in three-dimensional normoxic culture showed premature capillary formation. Organized progenitor cell movement was reconstituted when cells were co-transfected with Dicer siRNA and low-dose Mir218-5p mimic. A Mir218-2 knockout was generated to assess the significance of miR-218-2 in a mammalian model. Mir218-2-5p expression was decreased in Mir218-2-/- embryos at E16.5. Mir218-2-/- decreased CD34+ angioblasts in the ureteric bud at E16.5 and were nonviable. Mir218-2+/- decreased peritubular capillary density at postnatal day 14 and increased serum creatinine after ischemia in adult mice. Systemic injection of miR-218-5p decreased serum creatinine after injury. These experiments demonstrate that miR-218 expression can be triggered by hypoxia and modulates EPC migration in the kidney.

Histomorphometric evaluation of the rat kidney submitted to warm ischemia and the protective effect of resveratrol

BACKGROUND

The objective of this study is to quantitatively evaluate the protective effects of resveratrol for using during renal warm ischemia.

METHODS

Rats were allocated into 4 groups: Sham, Sham Resveratrol, Ischemia, Ischemia Resveratrol. Sham Resveratrol and Ischemia Resveratrol received resveratrol before surgery. Ischemia and Ischemia Resveratrol had renal vessels clamped. Animals were euthanized four weeks after. Serum urea and creatinine were measured. Renal weight and volume, cortex-non-cortex areas ratio, cortical volume, glomerular volumetric density, volume-weighted mean glomerular volume and number of glomeruli per kidney were evaluated.

RESULTS

Serum urea in Ischemia increased by 10.4% compared to Sham and no differences were observed among Ischemia Resveratrol and sham groups. The glomerular volumetric density and number of glomeruli of Ischemia were lower than Sham but Ischemia Resveratrol had no difference compared to sham groups.

CONCLUSIONS

Preoperative administration of resveratrol has renoprotective effects, preventing the glomerular number reduction observed in warm ischemia.

Comparison of 3-dimensional laparoscopy and conventional laparoscopy in the treatment of complex renal tumor with partial nephrectomy: A propensity score-matching analysis

To compare the efficacies of 3-dimensional laparoscopic partial nephrectomy and conventional laparoscopic partial nephrectomy for complex renal tumors. The complex renal tumors was defined as Preoperative Aspects and Dimensions Used for an anatomical (PADAU) ≥10, including some cT1b tumors.This was a retrospective analysis of patients with local complex renal tumors who presented to our hospital from January 2014 to January 2018. All patients were managed with laparoscopic partial nephrectomy (LPN) or 3-dimensional partial nephrectomy (3DLPN).There were 48 patients in the LPN group and 60 in the 3DLPN group. In the matched groups, demographic and tumor characteristics including Charlson Comorbidity Index, PADUA, based on the preoperative images, were similar. By contrast, 3DLPN achieved better results in terms of warm ischemia time (19 vs 27 minutes), operation time (105 vs 128 minutes), postoperative complications (14.9% vs 23.4%), and marginal width (0.6 cm vs 0.4 cm). We found statistically significant differences in terms of length of stay, estimated blood loss (EBL), positive surgical margin (PSM), and conversion to open or radical nephrectomy (RN). Median follow-up time was 17 and 18.5 months for the LPN and 3DLPN groups, respectively. The recovery of renal function (% change eGFR, 0 vs -8.7) was significantly different between the 3DLPN and LPN groups, whereas 12-month recurrence-free survival did not differ.Both 3-dimensional laparoscopic nephron-sparing nephrectomy and conventional laparoscopic partial nephrectomy are safe, effective, and acceptable approaches to treating complex renal tumors, while the former may facilitate tumor resection and renorrhaphy for challenging cases, offering a minimally invasive surgical option for patients who may otherwise require open surgery.

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

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

Outcome of kidney function after ischaemic and zero-ischaemic laparoscopic and open nephron-sparing surgery for renal cell cancer

Background

Nephron-sparing surgery (NSS) remains gold standard for the treatment of localised renal cell cancer (RCC), even in case of a normal contralateral kidney. Compared to radical nephrectomy, kidney failure and cardiovascular events are less frequent with NSS. However, the effects of different surgical approaches and of zero ischaemia on the postoperative reduction in renal function remain controversial.

We aimed to investigate the relative short- and long-term changes in estimated glomerular filtration rate (eGFR) after ischaemic or zero-ischaemic open (ONSS) and laparoscopic NSS (LNSS) for RCC, and to analyse prognostic factors for postoperative acute kidney injury (AKI) and chronic kidney disease (CKD) stage ≥3.

Methods

Data of 444 patients (211 LNSS, 233 ONSS), including 57 zero-ischaemic cases, were retrospectively analysed. Multiple regression models were used to predict relative changes in renal function. Natural cubic splines were used to demonstrate the association between ischaemia time (IT) and relative changes in renal function.

Results

IT was identified as significant risk factor for short-term relative changes in eGFR (ß = − 0.27) and development of AKI (OR, 1.02), but no effect was found on long-term relative changes in eGFR. Natural cubic splines revealed that IT had a greater effect on patients with baseline eGFR categories ≥G3 concerning short-term decrease in renal function and development of AKI. Unlike LNSS, ONSS was significantly associated with short-term decrease in renal function (ß = − 13.48) and development of AKI (OR, 3.87). Tumour diameter was associated with long-term decrease in renal function (ß = − 1.76), whereas baseline eGFR was a prognostic factor for both short- (ß = − 0.20) and long-term (ß = − 0.29) relative changes in eGFR and the development of CKD stage ≥3 (OR, 0.89).

Conclusions

IT is a significant risk factor for AKI. The short-term effect of IT is not always linear, and the impact also depends on baseline eGFR. Unlike LNSS, ONSS is associated with the development of AKI. Our findings are helpful for surgical planning, and suggest either the application of a clampless NSS technique or at least the shortest possible IT to reduce the risk of short-time impairment of the renal function, which might prevent AKI, particularly regarding patients with baseline eGFR category ≥G3.

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

CONTEXT

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

OBJECTIVE

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSIONS

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

PATIENT SUMMARY

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

Acute kidney injury and intermediate-term renal function after clampless partial nephrectomy

OBJECTIVES

To evaluate the incidence and predictors of acute kidney injury after clampless partial nephrectomy, and its impact on intermediate-term renal function.

METHODS

The incidence and severity of acute kidney injury were assessed for 262 patients undergoing clampless partial nephrectomy between 2010 and 2015. The association between perioperative covariates and acute kidney injury was evaluated using multivariate logistic regression analysis. An annual change in estimated glomerular filtration rate from 1 year after surgery was calculated according to the presence or absence of acute kidney injury. An impact of acute kidney injury on postoperative renal impairment, defined as a ≥25% estimated glomerular filtration rate decrease, was evaluated.

RESULTS

Overall, 21 (8.0%) patients experienced grade 1 acute kidney injury after clampless partial nephrectomy, and grade ≥2 acute kidney injury was not observed. High tumor complexity was the only independent predictor of acute kidney injury. Estimated glomerular filtration rate in patients with acute kidney injury improved within 1 year, and annual estimated glomerular filtration rate changes were similar among patients with or without acute kidney injury. Ultimately, 13 (5.0%) patients showed postoperative renal impairment during the median follow-up period of 37 months. Advanced age and diabetes mellitus were independent risk factors for renal impairment, but acute kidney injury was not.

CONCLUSIONS

The incidence and severity of acute kidney injury after clampless partial nephrectomy are low. Low-grade acute kidney injury after clampless partial nephrectomy does not seem to affect intermediate-term renal function.