Competing Risks Analysis of Kidney Transplant Waitlist Outcomes: Two Important Statistical Perspectives.

Modern competing risks analysis has 2 primary goals in clinical epidemiology as follows: (i) to maximize the clinician's knowledge of etiologic associations existing between potential predictor variables and various cause-specific outcomes via cause-specific hazard models, and (ii) to maximize the clinician's knowledge of noteworthy differences existing in cause-specific patient risk via cause-specific subdistribution hazard models (cumulative incidence functions [CIFs]). A perfect application exists in analyzing the following 4 distinct outcomes after listing for a deceased donor kidney transplant (DDKT): (i) receiving a DDKT, (ii) receiving a living donor kidney transplant (LDKT), (iii) waitlist removal due to patient mortality or a deteriorating medical condition, and (iv) waitlist removal due to other reasons. It is important to realize that obtaining a complete understanding of subdistribution hazard ratios (HRs) is simply not possible without first having knowledge of the multivariable relationships existing between the potential predictor variables and the cause-specific hazards (perspective #1), because the cause-specific hazards form the "building blocks" of CIFs. In addition, though we believe that a worthy and practical alternative to estimating the median waiting-time-to DDKT is to ask, "what is the conditional probability of the patient receiving a DDKT, given that he or she would not previously experience one of the competing events (known as the cause-specific conditional failure probability)," only an appropriate estimator of this conditional type of cumulative incidence should be used (perspective #2). One suggested estimator, the well-known "one minus Kaplan-Meier" approach (censoring competing events), simply does not represent any probability in the presence of competing risks and will almost always produce biased estimates (thus, it should never be used).

Optimizing the kidney donor pool: transplanting donor kidneys after partial nephrectomy of masses or cysts.

Background: A limiting factor in expanding the kidney donor pool is donor kidneys with renal tumors or cysts. Partial nephrectomy (PN) to remove these lesions prior to transplantation may help optimize organ usage without recurrence of malignancy or increased risk of complications. Methods: We retrospectively analyzed all recipients of a living or deceased donor graft between February 2009 and October 2022 in which a PN was performed prior to transplant due to the presence of one or more concerning growths. Donor and recipient demographics, perioperative data, donor allograft pathology, and recipient outcomes were obtained. Results: Thirty-six recipients received a graft in which a PN was performed to remove suspicious masses or cysts prior to transplant. Majority of pathologies turned out to be a simple renal cyst (65%), followed by renal cell carcinoma (15%), benign multilocular cystic renal neoplasm (7.5%), angiomyolipoma (5%), benign renal tissue (5%), and papillary adenoma (2.5%). No renal malignancy recurrences were observed during the study period (median follow-up: 67.2 months). Fourteen complications occurred among 11 patients (30.6% overall) during the first 6mo post-transplant. Mean eGFR (± standard error) at 36 months post-transplant was 51.9 ± 4.2 ml/min/1.73 m2 (N = 23). Three death-censored graft losses and four deaths with a functioning graft and were observed. Conclusion: PN of renal grafts with suspicious looking masses or cysts is a safe option to optimize organ usage and decrease the kidney non-use rate, with no observed recurrence of malignancy or increased risk of complications.

Surgical modifications to the conventional kidney transplant technique - the miami transplant institute approach: a retrospective cohort study.

BACKGROUND: At our center, surgical modifications to the conventional kidney transplant technique were developed with two goals in mind: to minimize the risk of developing post-transplant urologic/vascular/other surgical complications, and to simultaneously eliminate the need for initial ureteral stent placement and surgical drainage. METHODS: Here, we describe these modifications along with(what we believe are) their advantages over the conventional technique: creating an abdominal flap for easier abdominal closure(reflecting the parietal peritoneum from the abdominal wall), mobilizing the bladder before transplant(creating more space for bladder dissection, allowing it to move upward during abdominal wall closure), minimizing the dissection of iliac vessels to only anterior lymphatic tissue(attempting to minimize the incidence of fluid collections), using plastic arterial vascular bulldog clamps(causing less trauma to the iliac artery), performing vascular anastomosis of the renal artery first(making it easier for the surgeon to perform this anastomoses), creating longer ureteral spatulation, and inclusion of bladder mucosa along with some detrusor muscle layer in performing the ureteral anastomosis(attempting to minimize the incidence of urologic complications). Of note, no initial ureteral stent placement or surgical drainage was used. We report our experience during the first 12mo post-transplant of a single transplant surgeon who used each of these modifications among 707 consecutive recipients of kidney-alone transplants at our center since 2014. RESULTS: During the first 12mo post-transplant, 2.3%(16/707) of patients developed a urologic complication; only 1.0%(7/707) required surgical repair of their original ureteroneocystostomy. Additionally, 2.7%(19/707) developed a vascular complication; 8.8%(62/707) developed some other type of surgical complication(wound complication, lymphocele development, or development of a peri-renal hematoma or peri-renal collection). These overall results were clearly advantageous when compared with other studies. CONCLUSION: We believe that this modified kidney transplant technique clearly helped in reducing post-transplant risks of developing urologic/vascular/other surgical complications. Importantly, these results were achieved without initial ureteral stent placement or surgical drainage.

Determinants of hyperparathyroidism in children after kidney transplantation.

INTRODUCTION: Hyperparathyroidism (HPT) can contribute to metabolic bone disease following kidney transplantation. We evaluated post-transplant trends in intact parathyroid hormone (iPTH) and determined predictors of HPT in pediatric kidney transplant (KTx) recipients. METHODS: In this single-center study, retrospective data were collected on 88 children from 2013 to 2019. Data collected included dialysis vintage, biochemical parameters, post-transplant trends in iPTH, 25(OH)Vitamin D levels and estimated glomerular filtration rate (eGFR ml/min/1.73 m2 ). Pre-transplant treatment for HPT was quantified with a Treatment Burden score (TB, score range: 0-100). After log-transforming skewed variables (iPTH and eGFR), multivariable linear regression was performed to determine predictors of log {iPTH} at 6 and 36 months (mo) post-transplant. RESULTS: Median age was 12.8 (range: 1.9-20.5) years, and dialysis vintage was 11.2 (range: 0.0-112.9) months. The majority were of Hispanic and African Ancestry (77.3%). Median post-transplant iPTH was 69.5 (range: 1.8-306.8) pg/ml at 6 mo with a gradual downward trend to 59.0 (range: 28.0-445.0) pg/ml at 36 mo. Significant multivariable predictors of higher log {iPTH} post-transplant included longer dialysis vintage, higher TB, and lower log{eGFR} at 6 mo, and higher TB, lower log{eGFR}, and deceased donor transplant at 36 mo. CONCLUSIONS: Recognition of risk factors for HPT and monitoring iPTH post-transplant may facilitate timely interventions to mitigate cardiovascular and bone disease in pediatric KTx recipients. KEY MESSAGE: Describe serial trends in intact PTH after kidney transplantation. Pre- and post-transplant factors that contribute to persistence or re-occurrence of hyperparathyroidism after kidney transplantation in children include longer dialysis vintage, high pre-transplant treatment burden and decreased post-transplant GFR. Recognition of these factors, and monitoring intact PTH after kidney transplantation, could facilitate timely interventions to mitigate cardiovascular and bone disease in children.

Liver Inclusion Appears to Be Protective Against Graft Loss-Due-to Chronic But Not Acute Rejection Following Intestinal Transplantation.

In intestinal transplantation, while other centers have shown that liver-including allografts have significantly more favorable graft survival and graft loss-due-to chronic rejection (CHR) rates, our center has consistently shown that modified multivisceral (MMV) and full multivisceral (MV) allografts have significantly more favorable acute cellular rejection (ACR) and severe ACR rates compared with isolated intestine (I) and liver-intestine (LI) allografts. In the attempt to resolve this apparent discrepancy, we performed stepwise Cox multivariable analyses of the hazard rates of developing graft loss-due-to acute rejection (AR) vs. CHR among 350 consecutive intestinal transplants at our center with long-term follow-up (median: 13.5 years post-transplant). Observed percentages developing graft loss-due-to AR and CHR were 14.3% (50/350) and 6.6% (23/350), respectively. Only one baseline variable was selected into the Cox model indicating a significantly lower hazard rate of developing graft loss-due-to AR: Transplant Type MMV or MV (p < 0.000001). Conversely, two baseline variables were selected into the Cox model indicating a significantly lower hazard rate of developing graft loss-due-to CHR: Received Donor Liver (LI or MV) (p = 0.002) and Received Induction (p = 0.007). In summary, while MMV/MV transplants (who receive extensive native lymphoid tissue removal) offered protection against graft loss-due-to AR, liver-containing grafts appeared to offer protection against graft loss-due-to CHR, supporting the results of other studies.

The Impact of Ethnicity on Research Authorization at the Time of Organ Donation: A Single-Center Experience Among Deceased Donor Kidney Transplantation.

Objective: Research on deceased organ donors is needed to expand the donor organ supply. Little is known about the rate of research authorization among various groups. We aimed to determine the percentage of research authorization by the deceased donor family across different donor characteristics. Materials and Methods: We performed a retrospective review of deceased donors referred to one U.S. institution for kidney transplantation over a 12-month period. Organs were offered from multiple organ procurement organizations (OPO) across the United States. Stepwise logistic regression was performed to determine the predictors of research authorization. Results: From 10/2018 to 10/2019, 437 deceased donors were accepted for transplantation. 81.5% came from OPOs outside our donor service area and 18.5% from our local OPO. Overall, research authorization was declined in 24.0% of donors. Declined authorization was highest among Black donors (42.0%) compared to Whites (16.3%) and Hispanics (26.9%); p=0.000006. Donors <35 years had highest declined research authorization at 42.9% compared to older donors. There were no significant differences between individual OPOs. Conclusion: Deceased donor research authorization declined at the time of organ donation is higher among Black and younger donors. There is an immediate need for the transplant and donor community to develop best-practices to eliminate barriers to research in organ transplantation.

Long-term effects of average calcineurin inhibitor trough levels (over time) on renal function in a prospectively followed cohort of 150 kidney transplant recipients.

More favorable clinical outcomes with medium-term follow-up have been reported among kidney transplant recipients receiving maintenance therapy consisting of "reduced-tacrolimus (TAC) dosing," mycophenolate mofetil (MMF), and low-dose corticosteroids. However, it is not clear whether long-term maintenance therapy with reduced-calcineurin inhibitor (CNI) dosing still leads to reduced renal function. A prospectively followed cohort of 150 kidney transplant recipients randomized to receive TAC/sirolimus (SRL) versus TAC/MMF versus cyclosporine microemulsion (CSA)/SRL, plus low-dose maintenance corticosteroids, now has 20 years of post-transplant follow-up. Average CNI trough levels over time among patients who were still alive with functioning grafts at 60, 120, and 180 months post-transplant were determined and ranked from smallest-to-largest for both TAC and CSA. Stepwise linear regression was used to determine whether these ranked average trough levels were associated with the patient's estimated glomerular filtration rate (eGFR) at those times, particularly after controlling for other significant multivariable predictors. Experiencing biopsy-proven acute rejection (BPAR) and older donor age were the two most significant multivariable predictors of poorer eGFR at 60, 120, and 180 months post-transplant (p < 000001 and 0.000003 for older donor age at 60 and 120 months; p = 0.00008 and <0.000001 for previous BPAR at 60 and 120 months). Assignment to CSA also implied a significantly poorer eGFR (but with less magnitudes of effect) in multivariable analysis at 60 and 120 months (p = 0.01 and 0.002). Higher ranked average CNI trough levels had no association with eGFR at any timepoint in either univariable or multivariable analysis (p > 0.70). Long-term maintenance therapy with reduced-CNI dosing does not appear to cause reduced renal function.

The importance of avoiding time-dependent bias when testing the prognostic value of an intervening event - Two acute cellular rejection examples in intestinal transplantation.

In testing the prognostic value of the occurrence of an intervening event (clinical event that occurs posttransplant), 3 proper statistical methodologies for testing its prognostic value exist (time-dependent covariate, landmark, and semi-Markov modeling methods). However, time-dependent bias has appeared in many clinical reports, whereby the intervening event is statistically treated as a baseline variable (as if it occurred at transplant). Using a single-center cohort of 445 intestinal transplant cases to test the prognostic value of first acute cellular rejection (ACR) and severe (grade of) ACR on the hazard rate of developing graft loss, we demonstrate how the inclusion of such time-dependent bias can lead to severe underestimation of the true hazard ratio (HR). The (statistically more powerful) time-dependent covariate method in Cox's multivariable model yielded significantly unfavorable effects of first ACR (P < .0001; HR = 2.492) and severe ACR (P < .0001; HR = 4.531). In contrast, when using the time-dependent biased approach, multivariable analysis yielded an incorrect conclusion for the prognostic value of first ACR (P = .31, HR = 0.877, 35.2% of 2.492) and a much smaller estimated effect of severe ACR (P = .0008; HR = 1.589; 35.1% of 4.531). In conclusion, this study demonstrates the importance of avoiding time-dependent bias when testing the prognostic value of an intervening event.

Retroperitoneal kidney transplantation with liver and native kidney mobilization: a safe technique for pediatric recipients.

BACKGROUND: Pediatric kidney transplant (KT) using larger, deceased or living donor adult kidneys can be challenging in the pediatric population due to limited space in the retroperitoneum. Liver and native kidney (L/NK) mobilization techniques can be used in smaller and younger transplant recipients to aid in retroperitoneal placement of the renal allograft. Here, we compare the clinical outcomes of pediatric retroperitoneal KT with and without L/NK mobilization. METHODS: We retrospectively analyzed pediatric renal transplant recipients treated between January 2015 and May 2021. Donor and recipient demographics, intraoperative data, and recipient outcomes were included. Recipients were divided into two groups according to the surgical technique utilized: with L/NK mobilization (Group 1) and without L/NK mobilization (Group 2). Baseline variables were described using frequency distributions for categorical variables and means and standard errors for continuous variables. Tests of association with the likelihood of using L/NK mobilization were performed using standard χ2 tests, t tests, and the log-rank test. RESULTS: Forty-six pediatric recipients were evaluated and categorized into Group 1 (n = 26) and Group 2 (n = 20). Recipients in Group 1 were younger (6.7 ± 0.8 years vs. 15. 3 ± 0.7, P < 0.001), shorter (109.5 ± 3.7 vs. 154.2 ± 3.8 cm, P < 0.001) and weighed less (21.4 ± 2.0 vs. 48.6 ± 3.4 kg, P < 0.001) than those in Group 2. Other baseline characteristics did not differ between Groups 1 and 2. One urologic complication was encountered in Group 2; no vascular or surgical complications were observed in either group. Additionally, no stents or drains were used in any of the patients. There were no cases of delayed graft function or graft primary nonfunction. The median follow-up of the study was 24.6 months post-transplant. Two patients developed death-censored graft failure (both in Group 2, P = 0.22), and there was one death with a functioning graft (in Group 2, P = 0.21). CONCLUSIONS: Retroperitoneal liver/kidney mobilization is a feasible and safe technique that facilitates implantation of adult kidney allografts into pediatric transplant recipients with no increased risk of developing post-operative complications, graft loss, or mortality.

En Bloc Resection of Right Renal Cell Carcinoma and Inferior Vena Cava Tumor Thrombus Without Caval Reconstruction: Is It Safe to Divide the Left Renal Vein?

Introduction: It has been suggested that inferior vena cava (IVC) reconstruction following resection of retroperitoneal tumors with IVC tumor thrombus (TT) is not required when adequate collateral circulation is present. There are no reports evaluating mid-term effects on renal function in these patients. The purpose of this study was to assess renal function after en bloc resection of right renal cell carcinoma (RCC) with obstructing IVC TT and the possible risks that may arise after left renal vein division. Materials and Methods: A bi-institutional retrospective review was performed over a 15-year period, assessing patients with right RCC and obstructing level II-IV TT. All patients underwent extensive evaluation and cardiology clearance, and informed consent was obtained for right radical nephrectomy and thrombectomy with or without IVC reconstruction with possible cardiopulmonary bypass (CPB). Patient demographics, tumor characteristics, intraoperative factors, complications, length of stay, and patient survival were evaluated. Preoperative creatinine was recorded, as was creatinine on the day of discharge and at 6 and 12 months postoperatively. Results: Twenty-two patients were included in the study. Median age at surgery was 62.5 (range: 45-79) years, and 19 (86%) of the patients were men. One patient (5%) had a level II thrombus, 14 patients (64%) had a level III thrombus (IIIa, n = 3; IIIb, n = 6; IIIc, n = 3; IIId, n = 2), and seven patients (32%) had a level IV thrombus. Intraoperatively, median estimated blood loss was 1.35 (range: 0.2-25) L. The median length of hospital stay was 11 (range: 5-50) days. Median preoperative creatinine was 1.20 (range: 0.40-2.70) mg/dl, and postoperatively, median creatinine was 1.3 (range: 0.86-2.20) mg/dl. Median creatinine levels at 6 months and 12 months postoperatively were 1.10 (range: 0.5-1.8) mg/dl and 1.40 (range: 0.6-2.0) mg/dl, respectively. Four patients died (range: 0.1-1.3 years), and median postoperative follow-up among the 18 ongoing survivors (at last follow-up) was 1.5 (range: 0.5-7.0) years. Conclusions: Resection of right RCC with an obstructing level II-IV TT without reconstruction of the IVC appears to not have a significant adverse effect on mid-term renal function after division of the left renal vein.

Predictors of Kidney Delayed Graft Function and Its Prognostic Impact following Combined Liver-Kidney Transplantation: A Recent Single-Center Experience.

Combined liver−kidney transplantation (CLKT) improves patient survival among liver transplant recipients with renal dysfunction. However, kidney delayed graft function (kDGF) still represents a common and challenging complication that can negatively impact clinical outcomes. This retrospective study analyzed the incidence, potential risk factors, and prognostic impact of kDGF development following CLKT in a recently transplanted cohort. Specifically, 115 consecutive CLKT recipients who were transplanted at our center between January 2015 and February 2021 were studied. All transplanted kidneys received hypothermic pulsatile machine perfusion (HPMP) prior to transplant. The primary outcome was kDGF development. Secondary outcomes included the combined incidence and severity of developing postoperative complications; development of postoperative infections; biopsy-proven acute rejection (BPAR); renal function at 1, 3, 6, and 12 months post-transplant; and death-censored graft and patient survival. kDGF was observed in 37.4% (43/115) of patients. Multivariable analysis of kDGF revealed the following independent predictors: preoperative dialysis (p = 0.0003), lower recipient BMI (p = 0.006), older donor age (p = 0.003), utilization of DCD donors (p = 0.007), and longer delay of kidney transplantation after liver transplantation (p = 0.0003). With a median follow-up of 36.7 months post-transplant, kDGF was associated with a significantly increased risk of developing more severe postoperative complication(s) (p < 0.000001), poorer renal function (particularly at 1 month post-transplant, p < 0.000001), and worse death-censored graft (p = 0.00004) and patient survival (p = 0.0002). kDGF may be responsible for remarkable negative effects on immediate and potentially longer-term clinical outcomes after CLKT. Understanding the important risk factors for kDGF development in CLKT may better guide recipient and donor selection(s) and improve clinical decisions in this increasing group of transplant recipients.

Creating a Single Inflow Orifice From Living Donor Kidney Allografts With Multiple Renal Arteries.

Background: Multiple renal arteries (MRA) are often encountered during living-donor kidney transplantation (LDKT), requiring surgeons to pursue complex renovascular reconstructions prior to graft implantation. With improvements in reconstruction and anastomosis techniques, allografts with MRA can be successfully transplanted with similar outcomes to allografts with a single renal artery. Here, we describe in detail various surgical techniques for reconstruction of MRA grafts with the intent of creating a single arterial inflow. Methods: We retrospectively reviewed the medical records of all LDKT recipients with laparoscopically procured MRA kidneys between March 2008 and July 2021. Recipient and donor characteristics, operative data, type of reconstruction, and recipient outcomes were analyzed. The primary outcomes were the incidence of developing delayed graft function (DGF) and/or a vascular or urological complication within 12 months post-transplant. Results: Seventy-three LDKT recipients of MRA donor allografts were evaluated. Two renal arteries (RA) were encountered in 62 allografts (84.9%) and three RA in 11 allografts (15.1%). Renal artery reconstruction was performed in 95.8% (70/73) of patients. Eighteen different reconstruction techniques of MRA were utilized, the most common being side-to-side anastomosis in allografts with two RA (N = 44) and side-to-side-to-side anastomosis in allografts with three RA (N = 4). Interposition grafting was performed in seven cases (9.6%). A single ostium was created in 69 cases (94.5%), and the median warm ischemia time was 27 (range 20-42) minutes. None of the patients developed DGF or post-operative vascular or urological complications. Median creatinine at 3, 6, and 12 months post-transplant remained stable at 1.1 mg/dl. With a median follow-up of 30.4 months post-transplant, only one graft failure has been observed-death-censored graft survival was 98.6%. Conclusion: Complex reconstruction techniques to create a single renal artery ostium for graft implantation anastomosis in allografts with MRA show acceptable warm ischemic times, with no increased risk of post-operative vascular or urological complications.

Graft Failure Due to Nonadherence among 150 Prospectively-Followed Kidney Transplant Recipients at 18 Years Post-transplant: Our Results and Review of the Literature.

Background: We previously reported that graft failure due to nonadherence (GFNA) was a major cause of graft loss in kidney transplantation. Here, among 150 prospectively-followed kidney transplant recipients at 18 years post-transplant, we provide: updated (longer-term) estimates of cause-specific graft loss probabilities, risk factors for developing GFNA, and detailed characterizations of patients' overt nonadherent (NA) behavior, including timing, extent, and clinical consequences. Methods: Determination of the patient becoming NA in taking his/her immunosuppressive medications, and the underlying cause of graft loss, were determined prospectively by the attending physicians. For never-functioning-graft, GFNA, GF due to causes other than NA (Other GF), and death with a functioning graft (DWFG), cumulative incidence functions were used to estimate the cumulative probabilities of cause-specific graft loss. Cox stepwise regression was used to determine significant multivariable predictors for the hazard rate of developing GFNA. Results: GFNA was a major cause of graft loss (22/150 patients), particularly among African-American and Hispanic recipients <50 years of age-at-transplant (20/56 experienced GFNA), with estimated percentages of such patients ever developing GFNA ranging between 36.9 and 41.5%. These patients were also at a higher risk of developing Other GF. For the remaining patients (2/94 experienced GFNA), estimated percentages of ever-developing GFNA were much lower (range: 0.0−6.7%). The major cause of graft loss among recipients ≥50 years of age was DWFG; GFNA rarely occurred among older recipients. In 21/22 GFNA patients, NA behavior lasted continuously from the time of developing NA until GFNA. In total, 28/150 patients became NA, and 67.9% (19/28) occurred beyond 36 months post-transplant. A total of 25 of 28 NA patients (89.3%) developed biopsy-proven acute rejection and/or chronic rejection that was directly attributed to the NA behavior. Lastly, 25/28 admitted to NA behavior, with financial and psychological components documented in 71.4% (20/28) and 96.4% (27/28) of NA cases, respectively. Conclusions: These results highlight the importance of performing serial monitoring of patients for overt NA behavior throughout their post-transplant follow-up. Financial and psychological components to NA behavior need to be simultaneously addressed with the goal of achieving complete avoidance/elimination of NA behavior among higher risk patients.

Pediatric kidney transplants with multiple renal arteries show no increased risk of complications compared to single renal artery grafts.

Background: Kidney allografts with multiple renal arteries (MRA) are not infrequent and have been historically associated with a higher risk of developing vascular and urologic complications. Reports of kidney transplantation using MRA allografts in the pediatric population remain scarce. The aim of this study was to evaluate if transplantation of allografts with MRA with a surgical intent of creating a single arterial inflow using vascular reconstruction techniques when required, and without the routine use of surgical drains or ureteral stents, is associated with an increased risk of complications when compared to single renal artery (SRA) grafts. Methods: We retrospectively analyzed all pediatric renal transplant recipients performed by a single surgeon at our center between January 2015 and June 2022. Donor and recipient demographics, intraoperative data, and recipient outcomes were included. Recipients were divided into two groups based on SRA vs. MRA. Baseline variables were described using frequency distributions for categorical variables and means and standard errors for continuous variables. Comparisons of those distributions between the two groups were performed using standard chi-squared and t-tests. Time-to-event distributions were compared using the log-rank test. Results: Forty-nine pediatric transplant recipients were analyzed. Of these, 9 had donors with MRA (Group 1) and 40 had donors with SRA (Group 2). Native kidney and liver mobilization was performed in 44.4% (4/9) of Group 1 vs. 60.0% (24/40) of Group 2 cases (p = 0.39). There were no cases of delayed graft function or graft primary nonfunction. No surgical drainage or ureteral stents were used in any of the cases. One patient in Group 2 developed a distal ureter stricture. The geometric mean serum creatinine at 6- and 12-months posttransplant was 0.7 */ 1.2 and 0.9 */ 1.2 mg/dl in Group 1 and 0.7 */ 1.1 and 0.7 */ 1.1 mg/dl in Group 2. Two death-censored graft failures were observed in Group 2, with no significant difference observed between the two groups (p = 0.48). Conclusions: Our study demonstrates that pediatric renal transplantation with MRA grafts, using a surgical approach to achieve a single renal artery ostium, can be safely performed while achieving similar outcomes as SRA grafts and with a low complication rate.

Surgical Management of Upper Urinary Tract Urothelial Cell Carcinoma with Venous Tumor Thrombus: A Liver Transplant-Based Approach.

Upper urinary tract urothelial cell carcinoma (UTUC) with venous tumor thrombus (TT) that extends into the renal vein (RV) and inferior vena cava (IVC) is a rare entity and its management is a surgical challenge. We report the largest single experience of surgical management of UTUC and accompanying venous TT with radical nephroureterectomy and tumor thrombectomy (RNATT) using transplant-based (TB) surgical techniques. From September 2003 to June 2021, nine patients with UTUC and venous TT underwent RNATT. Demographics, disease characteristics, surgical details, 30-day postoperative complications, and overall survival (OS) were analyzed. All nine patients had extension of the TT into the RV. Of those, seven had additional extension of the TT into the IVC. Venous TT level was categorized as 0 (n = 2), I (n = 2), II (n = 4), and IIIa (n = 1). Median tumor size was 12 cm (range 3-20 cm). Median estimated blood loss was 300 (range 150-1000) cc. One patient was still alive at last follow-up (4 months), and in total, eight patients have died with a median time-to-death of 12 months (range 10 days-24 months). RNATT using TB maneuvers like liver mobilization and pancreas-spleen en bloc mobilization provide excellent exposure to the retroperitoneal space and enable the safe removal of UTUC with venous TT.

Nonneoplastic Renal Parenchymal Changes in Renal Cell Carcinoma With Tumor Thrombus.

INTRODUCTION: Renal cell carcinoma may extend into the inferior vena cava (IVC) by the tumour thrombus (TT). Renal cell carcinoma with tumour thrombus (RCC/TT) could be associated with multiple collaterals making the surgery in cases of venous involvement very complex and challenging. The pathologic findings of non-neoplastic parenchymal changes in radical nephrectomy specimens of RCC/TT have not been well described. METHODS: We conducted a retrospective study of 200 nephrectomies for RCC/TT during eight years. We only included 22 patients who had a full histopathological examination of the resected nephrectomies, including the non-neoplastic parenchymal tissues. RESULTS: Median tumour thrombus level was III (range: II-IV), and median tumour diameter was 9.3 (range: 4-17) cm. Clear cell RCC was the most common tumour diagnosis in this cohort. Non-neoplastic renal pathologies included: (1) Global Glomerulosclerosis (GGS) in 90.9% (1-9% GGS in 15, 10-30% GGS in 4, >30% GGS in 1); (2) Interstitial fibrosis in 90.9% (mild in nine, moderate in nine, severe in 2); (3) Acute tubular injury in 14 (63.6%) patients; (4) Chronic inflammation in 77.3% (5-25% in 10, 26-50% in 7); (5) Arteriolosclerosis in all patients (mild, moderate and severe in 12, 9 and 1 patients, respectively); (6) Arteriolosclerosis: as none in 12, mild in six, moderate in four patients; (7) Focal Segmental Glomerulosclerosis in one patient. Our findings suggest that non-neoplastic parenchymal changes occur in the presence of RCC/TT. Neither tumour extension (via T-stage) nor tumour thrombus level were associated with the degree of any of these non-neoplastic parenchymal changes. CONCLUSIONS: Knowledge of the existence of these non-neoplastic parenchymal changes in addition to determining the tumour margin(s) will be important in caring for and early determining whether any specific medical intervention(s) to help preserve renal function in the remaining contralateral kidney becomes warranted.

No Benefit of Prophylactic Surgical Drainage in Combined Liver and Kidney Transplantation: Our Experience and Review of the Literature.

Background: Contrasting results have emerged from limited studies investigating the role of prophylactic surgical drainage in preventing wound morbidity after liver and kidney transplantation. This retrospective study analyzes the use of surgical drain and the incidence of wound complications in combined liver and kidney transplantation (CLKTx). Methods: A total of 55 patients aged ≥18 years were divided into two groups: the drain group (D) (n = 35) and the drain-free group (DF) (n = 20). Discretion to place a drain was based exclusively on surgeon preference. All deceased donor kidneys were connected to the LifePort Renal Preservation Machine® prior to transplantation, in both simultaneous and delayed technique of implantation of the renal allograft. The primary outcome was the development of superficial/deep wound complications during the study follow-up. Secondary outcomes included the development of delayed graft function (DGF) of the transplanted kidney, primary non-function (PNF) and early allograft dysfunction (EAD) of the transplanted liver, graft failure, graft and patient survival, overall post-operative morbidity rate and length of hospital stay. Results: With a median follow-up of 14.4 months after transplant, no difference in the incidence of superficial/deep wound complications, except for hematomas, in collections size, intervention rate, PNF, EAD, graft failure and patient survival, was observed between the 2 groups. Significantly lower level of platelets, higher INR values, DGF, morbidity rates and length of hospital stay were reported post-operatively in the D group. Pre-operative hypoalbuminemia and longer CIT were included in the propensity score for receiving a drain and were associated with a significantly higher rate of developing a hematoma post-transplant. Conclusions: Absence of the surgical drain did not appear to adversely affect wound morbidity compared to the prophylactic use of drains in renal transplant patients during CLKTx.

Midline Rotation of the Right Renal Hilum During Hand-Assisted Laparoscopic Living Donor Nephrectomy.

BACKGROUND/OBJECTIVES: Laparoscopic living donor nephrectomy (LLDN) of the right kidney is currently considered as part of standard of care; however, dealing with the renal hilum when performing ligation/division of its renal vessels is still a main concern. Here, we describe a simple-to-perform technique, i.e., flipping the fully mobilized right kidney to the midline so that the renal artery becomes anteriorly, which offers better visualization and easier dissection of the renal vessels (achieving maximized lengths) when performing hand-assisted LLDN of the right kidney. METHODS: Living donors who underwent hand-assisted LLDN of the right kidney, along with their respective renal transplant recipients, were included in this report. Donor characteristics included renal artery and vein lengths; recipient characteristics included creatinine at months 12 - 36. Graft vein and arterial anastomosis data were also reported. RESULTS: Nineteen living donors and 19 recipients, with median donor and recipient ages being 39 (24 - 60) and 53 (3 - 81) years, respectively, were included. None of the 38 patients had intra- or postoperative complications. Donor renal vein was anastomosed to the right external iliac vein (n = 16), right common iliac vein (n = 2), and inferior vena cava (n = 1). Gonadal vein (n = 1) and deceased donor iliac vein (n = 2) were used to increase the right renal vein length in 3 cases. Four donor kidneys had 2 arteries reconstructed side by side. None of the recipients developed any vascular or urological complications. CONCLUSIONS: The laparoscopic technique described is safe and allows better visualization of the right hilum, mainly the renal artery, and helps in stapling the renal vein and renal artery.