Radiomics in Kidney Transplantation: A Scoping Review of Current Applications, Limitations, and Future Directions.

Radiomics is increasingly applied to the diagnosis, management, and outcome prediction of various urological conditions. The purpose of this scoping review is to evaluate the current evidence of the application of radiomics in kidney transplantation, especially its utility in diagnostics and therapeutics. An electronic literature search on radiomics in the setting of transplantation was conducted on PubMed, EMBASE, and Scopus from inception to September 23, 2022. A total of 16 studies were included. The most widely studied clinical utility of radiomics in kidney transplantation is its use as an adjunct to diagnose rejection, potentially reducing the need for unnecessary biopsies or guiding decisions for earlier biopsies to optimize graft survival. Technology such as optical coherence tomography is a noninvasive procedure to build high-resolution optical cross-section images of the kidney cortex in situ and in real time, which can provide histopathological information of donor kidney candidates for transplantation, and to predict posttransplant function. This review shows that, although radiomics in kidney transplants is still in its infancy, it has the potential for large-scale implementation. Its greatest potential lies in the correlation with conventional established diagnostic evaluation for living donors and potential in predicting and detecting rejection postoperatively.

Off-clamp vs on-clamp robot-assisted partial nephrectomy: a systematic review and meta-analysis.

OBJECTIVE: To compare intra- and postoperative outcomes between off-clamp and on-clamp robot-assisted partial nephrectomy (RAPN), using data from randomised controlled trials (RCTs) or covariate-matched studies (propensity score-matched or matched-pair analysis). METHODS: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant literature review was conducted on PubMed, EMBASE, Scopus and CENTRAL for relevant studies comparing off-clamp to on-clamp RAPN. Primary outcomes were estimated blood loss, postoperative percentage decrease in estimated glomerular filtration rate (eGFR), and margin positive rate. Secondary outcomes were operative time, postoperative eGFR, length of stay, all postoperative complications, major complications, and need for transfusion. Random-effects meta-analyses were performed to generate mean differences (MDs) or odds ratios (ORs). RESULTS: A total of 10 studies (2307 patients) were shortlisted for analysis. There was no significant difference in estimated operative blood loss between off-clamp and on-clamp RAPN (MD 21.9 mL, 95% confidence interval [CI] -0.9 to 44.7 mL; P = 0.06, I2 = 58%). Off-clamp RAPN yielded a smaller postoperative eGFR deterioration (MD 3.10%, 95% CI 1.05-5.16%; P = 0.008, I2 = 13%) and lower odds of margin positivity (OR 0.62, 95% CI 0.40-0.94; P = 0.03, I2 = 0%). No significant differences were found for all secondary outcomes. CONCLUSIONS: Off-clamp and on-clamp RAPN are similarly effective approaches for selected renal masses. Within the classic trifecta of PN outcomes, off-clamp RAPN yields similar rates of perioperative complications and may possibly offer better preservation of renal function and reduced margin-positive rates.

Graft retrieval incisions in minimally invasive donor nephrectomy: Systematic review and network meta-analysis.

BACKGROUND: Various incisions are employed for graft extraction during minimally invasive donor nephrectomy, but an overarching synthesis of associated short-term donor outcomes is lacking. METHODS: An electronic literature search was conducted on PubMed, EMBASE and Scopus for studies comparing ≥2 graft extraction incisions in laparoscopic or robotic donor nephrectomy with ≥10 patients per arm. Eligible study designs included randomized trials, case-control, and cohort studies. Primary outcomes were donor length of stay (LOS); in-hospital analgesic requirement; and postoperative complications. Secondary outcomes were warm ischemia time (WIT), total operation time (TOT), and estimated blood loss (EBL). Random-effects Frequentist network meta-analyses were conducted for all outcomes. RESULTS: Twenty-nine studies (4702 patients) were shortlisted. Six incisions were analyzed: iliac, Pfannenstiel, midline hand-assisted laparoscopic (HAL), midline umbilical, flank and transvaginal natural orifice transluminal endoscopic surgery (NOTES). The flank incision had significantly longer LOS than all other incisions. LOS was significantly longer in Pfannenstiel than iliac incision (mean difference [MD] = 0.29, 95%CI = 0.002-0.58 days). Midline HAL had significantly shorter TOT than most other incisions. Midline umbilical incisions had significantly higher WIT than midline HAL and Pfannenstiel incisions. Midline HAL had shorter WIT than transvaginal NOTES (MD = 0.80, 95%CI = 0.05-1.56 min). No major differences were seen in analgesia requirement, postoperative complications and EBL. CONCLUSION: Six different incisions for graft retrieval are broadly comparable across most short-term outcomes although long-term outcomes remain to be elucidated. Iliac and Pfannenstiel incisions yielded similar outcomes besides marginally lower LOS for the former. Midline incision for HAL may be associated with shorter TOT, and transvaginal NOTES is an effective technique for selected female donors. TRIAL REGISTRATION: PROSPERO CRD42023445407.

Single versus multiple renal arteries in living donor kidney transplantation: A systematic review and patient-level meta-analysis.

INTRODUCTION: Grafts with multiple renal arteries (MRAs) were historically considered a relative contraindication to transplantation due to the higher risk of vascular and urologic complications. This study aimed to evaluate graft and patient survival between single renal artery (SRA) and MRA living-donor kidney transplants. METHODS: An electronic literature search was conducted on PubMed, EMBASE, and Scopus for prospective or retrospective studies comparing SRA versus MRA in living donor renal transplantation, with the provision of Kaplan-Meier curves for recipient overall survival (OS) or graft survival (GS). A graphical reconstructive algorithm was used to obtain OS and GS of individual patients, which was then pooled under random-effects individual patient data (IPD) meta-analysis using Cox-models to determine hazard ratios (HRs) and 95% confidence intervals (CIs). Meta-regression of baseline covariates versus HRs of OS and GS was performed for variables reported in 10 or more studies. RESULTS: Fourteen studies were retrieved, of which 13 (8400 patients) reported OS and 9 (6912 patients) reported GS. There were no significant differences in OS (shared-frailty HR = .94, 95%CI = .85-1.03, p = .172) or GS (shared-frailty HR = .95, 95%CI = .83-1.08, p = .419) between SRA and MRA. This comparison remained non-significant even when restricted to open- or laparoscopic-only studies. Meta-regression yielded no significant associations of GS with donor age, recipient age, and percentage of double renal arteries within the MRA arm. CONCLUSIONS: The similar rates of GS and OS between MRA and SRA grafts suggest that there is no need for discrimination between the two when evaluating donors for nephrectomy.

The Utility of Intraoperative Near Infrared Fluorescence (NIR) Imaging with Indocyanine Green (ICG) for the Assessment of Kidney Allograft Perfusion.

BACKGROUND: Near infrared light (NIR) fluorescence imaging with indocyanine green (ICG) has been used in various aspects of surgery, such as in the assessment of vascular anastomosis, tissue perfusion, and the identification of lymph nodes. In this study we evaluated the utility of NIR/ICG fluorescence imaging in kidney transplantation. MATERIALS AND METHODS: NIR/ICG imaging was used to assess allograft perfusion in n=1 living donor (LDRT) and n=2 deceased donor (DDRT) renal transplantations, performed in February 2017. The allograft arterial and venous anastomoses were done end-to-side to the corresponding recipient external iliacs, and ureteroneocystostomies were performed for urinary reconstructions. After completion of vascular anastomosis, ICG was given as intravenous bolus at 0.3mg/kg, followed by visual assessment of tissue perfusion and vascular anastomoses at 1-minute interval using fluorescence imaging (KARL STORZ NIR/ICG System). RESULTS: Homogenous global fluorescence of the allograft and vascular anastomosis was observed in all 3 cases. Immediate postoperative perfusion studies showed patent inflow and outflow vessels and well perfused transplanted kidneys. Immediate graft function was observed in 2 recipients (1 LDRT and 1 DDRT). One session of haemodialysis was performed in 1 DDRT recipient, for high serum potassium in the immediate postoperative setting, who otherwise had good urine output and serially declining serum creatinine. CONCLUSIONS: NIR/ICG fluorescence imaging can be useful in renal transplantation for the intraoperative assessment of allograft perfusion, especially in complex cases with multiple renal arteries and vascular reconstructions.

TFE3-Expressing Epithelioid Rich Perivascular Epithelioid Cell Neoplasm (PEComa) of the Bladder with Unusual Benign Course.

Perivascular epithelioid cell tumor (PEComa) is an uncommon tumor which presents with epithelioid and spindled cell morphology and is immunoreactive for myogenic and melanocytic markers. Recently, a subset of PEComas has been reported to harbor TFE3 gene rearrangement.In this case report, we describe a TFE3-expressing primary bladder PEComa in a 27-year-old male patient with acute myeloid leukaemia in remission. The tumor displayed epithelioid morphology with surrounding delicate blood vessels and was devoid of a prominent spindle cell component. Malignant features were not identified. The tumor expressed HMB45, CD117, and focal patchy positive expression for SMA. TFE3 gene translocation was confirmed by Fluorescence in-situ hybridization. RT-PCR assay confirmed the presence of SFPQ-TFE3 gene fusion.In contrast to previously reported aggressive TFE3 gene-rearranged bladder PEComa cases, our case shows benign histologic and clinical features. Current clinical follow-up also shows a benign course.