Clamping renal artery alone produces less ischemic damage compared to clamping renal artery and vein together in two animal models: near-infrared tissue oximetry and quantitation of 8-isoprostane levels

Robotic partial nephrectomy: Techniques for complex tumors

Robotic assisted partial nephrectomy is an effective and minimally invasive approach that has gained significant popularity in the past 20 years. Guidelines support prioritizing partial nephrectomy in small renal masses when technically feasible, given improvement in long term renal function and cardiovascular risk. Increasing surgeon comfort with the robotic platform has allowed for the removal of larger and more complex tumors. There are a vast number of surgical techniques described in the literature for dissection, hilum clamping, tumor resection and renorrhaphy. We aim to describe and summarize different considerations and techniques to utilize when performing robotic assisted partial nephrectomy in complex renal masses. In this review, we specifically focus on masses with higher tumor complexity (RENAL score ≥10, those that involve or about the hilum or are invasive into the renal sinus).

Comparison of renal function between the artery and vein clamp and artery-only clamp in robot-assisted partial nephrectomy for moderate- to high-complexity renal masses: A propensity-matched study

OBJECTIVE

Artery and vein (AV) clamps can control venous bleeding in the surgical field and prevent carbon dioxide embolism, especially when large veins are expected to open. However, whether AV clamps cause more renal damage than artery-only (AO) clamps remains unclear. This study aimed to compare renal function and blood loss in surgeries using AO and AV clamps based on high RENAL nephrometry scores (RNS) in robot-assisted partial nephrectomy (RAPN).

METHODS

We retrospectively analyzed the medical records of 500 patients who underwent RAPN between March 2016 and December 2021. We performed 1:1 propensity matching for these patients.

RESULTS

A total of 340 patients with pathological malignancies who were followed up for at least 12 months were included in this analysis. A total of 291 patients with AO clamping and 49 patients with AV clamping were included. Overall, the AV clamp group had higher total RNSs and larger diameters than the AO clamp group. Propensity score-matched analysis included 37 patients in each clamp group. The median warm ischemia times of the AV and AO clamps were 25 and 22 min, respectively, with no significant difference. There were no statistically significant differences between the groups in the amount of blood loss, rate of acute kidney injury (AKI), or renal function at 1, 3, or 12 months post-RAPN.

CONCLUSION

Compared with the AO clamp, the AV clamp did not have a detrimental impact on blood loss or renal dysfunction. Consequently, AV clamps may be considered for patients presenting with moderate-to-high-complexity RNSs.

Extravasation of Blood and Blood Toxicity Drives Tubular Injury from RBC Trapping in Ischemic AKI

Red blood cell (RBC) trapping is common in ischemic acute kidney injury (AKI) and presents as densely packed RBCs that accumulate within and engorge the kidney medullary circulation. In this study, we tested the hypothesis that "RBC trapping directly promotes tubular injury independent of extending ischemia time." Studies were performed on rats. Red blood cell congestion and tubular injury were compared between renal arterial clamping, venous clamping, and venous clamping of blood-free kidneys. Vessels were occluded for either 15 or 45 min with and without reperfusion. We found that RBC trapping in the medullary capillaries occurred rapidly following reperfusion from renal arterial clamping and that this was associated with extravasation of blood from congested vessels, uptake of blood proteins by the tubules, and marked tubular injury. To determine if this injury was due to blood toxicity or an extension of ischemia time, we compared renal venous and arterial clamping without reperfusion. Venous clamping resulted in RBC trapping and marked tubular injury within 45 min of ischemia. Conversely, despite the same ischemia time, RBC trapping and tubular injury were minimal following arterial clamping without reperfusion. Confirming the role of blood toward tubular injury, injury was markedly reduced in blood-free kidneys with venous clamping. Our data demonstrate that RBC trapping results in the rapid extravasation and uptake of blood components by tubular cells, causing toxic tubular injury. Tubular toxicity from extravasation of blood following RBC trapping appears to be a major component of tubular injury in ischemic AKI, which has not previously been recognized.

Potential nephroprotective effects of angiotensin II type 2 receptor agonist Compound 21 in renal ischemia-reperfusion injury

This study examined the reno-protective potential of Compound 21 during renal ischemia-reperfusion injury by regulating the PI3K expression. 20 adult male Swiss-albino mice, aged 8-12 weeks and weighing 20-30g, were randomly assigned to four equal groups: sham, control, vehicle, and Compound 21. Serum urea, creatinine, inflammatory mediators, tissue 8-isoprostane, and myeloperoxidase were quantified using ELISA. Compared to the sham group, blood levels of urea, creatinine, TNF-α, IL-6, and IL-10 were significantly higher in the ischemia-reperfusion group than in the sham group (p<0.05). However, these indicators were significantly lower in the Compound 21 group (p<0.05). Histological analysis revealed significant renal tissue damage in the ischemia-reperfusion group (p<0.05), which was significantly reduced in the Compound 21 group (p<0.05). PCR results showed that PI3K expression was significantly lower (p<0.05) in the control group compared to the sham group but significantly higher in the Compound 21 group (p<0.05). Furthermore, P-AKT expression levels in the control group were considerably lower than in the sham group (p<0.05). On the other hand, the level of P-AKT expression in the Compound 21 group was significantly upregulated compared to the control group (p<0.05). The findings revealed that Compound 21 could mitigate renal dysfunction induced by ischemia-reperfusion injury in male mice through modulation of the PI3K/AKT signaling pathway, resulting in decreased levels of pro-inflammatory cytokines and renal oxidative stress markers.

The effect of renal artery-only or renal artery-vein clamping during partial nephrectomy on short and long-term functional results: Is clamping technique important?

PURPOSE

To evaluate the effect of artery-only (AO) and artery-vein (AV) clamping during partial nephrectomy (PN) on short- and long-term renal function outcome.

METHODS

Medical records of 154 patients in the AO group and 192 patients in the AV group who underwent open and minimally invasive (laparoscopic/robotic) PN between January 2011 and January 2018 were retrospectively assessed. Preoperative patient and tumor-specific characteristics in addition to perioperative factors and renal function outcomes were compared. The change in the estimated glomerular filtration rate (eGFR) from postoperative 1-3 days, 12 and 24 months after surgery was calculated. Acute kidney injury (AKI) was defined a as a > 25% reduction in eGFR.

RESULTS

There were no statistically significant differences between the clamping techniques in terms of postoperative 1-3 days, 12 and 24 months eGFR change percentage and risk of progression to chronic kidney disease (CKD). No significant difference in short- and long-term renal functions was found between the minimally invasive or open AO and AV clamping subgroups at any time point. In multivariate analysis, the R.E.N.A.L score (AO group p = 0.026, AV group p < 0.001) and preoperative eGFR (AO group p < 0.001, AV group p = 0.010) were strong predictors of the acute kidney injury in both groups. Older age (AO group p = 0.045, AV group p = 0.010) and preoperative eGFR (AO group p = 0.008, AV group p = 0.002) were significantly associated with CKD progression at 2-year follow-up in both groups.

CONCLUSION

AV clamping does not adversely affect postoperative renal function compared to AO clamping. Preoperative patient- and tumor-related factors are more important for renal function regardless of the clamping technique.

Comparison of Renal Artery vs Renal Artery-Vein Clamping During Partial Nephrectomy: A System Review and Meta-Analysis

Background: Although artery-only (AO) clamping has been proposed to minimize ischemic renal damage compared with artery-vein (AV) clamping, the benefit of AO clamping during laparoscopic partial nephrectomy (LPN) is still controversial. We performed a systematic review and meta-analysis to test the difference between AO clamping and AV clamping in partial nephrectomy (PN). Materials and Methods: A systematic review of the literature on PubMed, Web of Science, the Cochrane Library, and Embase was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement to search-related studies. Data were extracted using a reporting checklist proposed by the Meta-analysis of Observational Studies in Epidemiology Group. RevMan 5.3 software and Stata 12.0 were used to do meta-analysis. Results: The present meta-analysis included 2 retrospective and 3 prospective studies, including 242 patients who underwent AO clamping and 369 patients who underwent AV clamping, which compared AO and AV clamping in LPN for renal cell carcinoma. At baseline, no statistically significant differences were detected between AO and AV clamping groups in terms of body mass index (p = 0.23), tumor size (p = 0.95), but AO clamping group had significantly lower RENAL Score (fixed effects [FE]: weighted mean difference [WMD]: 0.36, p = 0.007). For surgical outcomes analysis, no significant difference was detected regarding to warm ischemia (p = 0.58), operating time (p = 0.40), transfusion rate (p = 0.58), and estimated blood loss (p = 0.35) between two groups. The assessment of renal function by creatinine value both at the early postoperative (p = 0.36) and at last follow-up (p = 0.38) revealed no difference. There was no significant difference in estimated glomerular filtration rate (eGFR) (p = 0.62), and at the early postoperative percentage decrease of eGFR (p = 0.79). However, a higher percentage decrease of eGFR decrease at last follow-up was demonstrated for the AV clamping group (FE: WMD: 2.42, p < 0.00001). Conclusion: These results suggest that AO clamping might be a better choice for PN in long term. Randomized controlled trial studies with larger sample numbers and long-term follow-up and split renal function assessment should be conducted in the future to confirm our conclusion.

Robotic partial nephrectomy: current technique and outcomes

Over the past decade, management of the T1 renal mass has focused on nephron-sparing surgery. Robotic partial nephrectomy has played an increasing role in the technique of preserving renal function by decreasing warm ischemia time, as well as optimizing outcomes of hemorrhage and fistula. Robot-assisted partial nephrectomy is designed to provide a minimally-invasive nephron-sparing surgical option utilizing reconstructive capability, decreasing intracorporeal suturing time, technical feasibility and safety. Ultimately, its benefits are resulting in its dissemination across institutions. Articulated instrumentation and three-dimensional vision facilitate resection, collecting system reconstruction and renorrhaphy, leading to decreased warm ischemia time while preserving oncological outcomes. The aim of the present review was to present our surgical sequence and technique, as well as review the current status of robot-assisted partial nephrectomy.