Obesity, Surgical Site Infection, and Outcome Following Renal Transplantation

Evaluating the safety of bariatric surgery as a bridge to kidney transplant: a retrospective cohort study

BACKGROUND

Bariatric surgery has been proven safe in end-stage kidney disease (ESKD); however, few studies have evaluated whether a history of bariatric surgery impacts transplant-specific outcomes. We hypothesize that a history of bariatric surgery at the time of transplant does not adversely impact transplant-specific outcomes.

METHODS

The IBM MarketScan Commercial Claims and Encounters database was queried for patients with a history of kidney transplant between 2000 and 2021. Patients were stratified into three groups based on bariatric surgery status and body mass index (BMI) at the time of transplant: patients with obesity (O), patients without obesity (NO), and patients with a history of bariatric surgery (BS). Inverse probability of treatment weighting was used to control for confounding. Adjusted hazard ratios (aHRs) describing the risk of transplant-specific and postoperative outcomes were estimated using weighted Kaplan-Meier curves. Primary outcomes included 30-day and 1-year risk of transplant-specific outcomes. Secondary outcomes included 30-day and 1-year postoperative complications and 30-day and 1-year risk of wound-related complications.

RESULTS

We identified 14,806 patients; 128 in the BS group, 1572 in the O group, and 13,106 in the NO group. There was no difference in 30-day or 1-year risk of transplant-specific complications between the BS and NO group or the O and NO group. Patients with obesity (O) were more likely to experience wound infection (aHR 1.49, 95% CI 1.12-1.99), wound dehiscence (aHR 2.2, 95% CI 1.5-3.2), and minor reoperation (aHR 1.52, 95% CI 1.23-1.89) at 1 year. BS patients had increased risk of wound infection at 1 year (aHR 2.79, 95% CI 1.26-6.16), but were without increase in risk of minor or major reoperation.

CONCLUSION

A history of bariatric surgery does not adversely affect transplant-specific outcomes after kidney transplant. Bariatric surgery can be safely utilized to improve the transplant candidacy of patients with obesity with CKD and ESKD.

Open Renal Transplantation in Obese Patients: A Correlation Study between BMI and Early and Late Complications with Implementation of a Prognostic Risk Score

BACKGROUND

Obesity is a global epidemic that affects millions worldwide and can be a deterrent to surgical procedures in the population waiting for kidney transplantation. However, the literature on the topic is controversial. This study evaluates the impact of body mass index (BMI) on complications after renal transplantation, and identifies factors associated with major complications to develop a prognostic risk score.

METHODS

A correlation analysis between BMI and early and late complications was first performed, followed by a univariate and multivariate logistic regression analysis. The 302 included patients were divided into obese (BMI ≥ 30 kg/m2) and non-obese (BMI ≤ 30 kg/m2) groups. Correlation analysis showed that delayed graft function (DGF) was the only obesity-associated complication (p = 0.044). Logistic regression analysis identified female sex, age ≥ 57 years, BMI ≥ 25 and ≥30 kg/m2, previous abdominal and/or urinary system surgery, and Charlson morbidity Score ≥ 3 as risk factors for significant complications. Based on the analyzed data, we developed a nomogram and a prognostic risk score.

RESULTS

The model's area (AUC) was 0.6457 (95% IC: 0.57; 0.72). The percentage of cases correctly identified by this model retrospectively applied to the entire cohort was 73.61%.

CONCLUSIONS

A high BMI seems to be associated with an increased risk of DGF, but it does not appear to be a risk factor for other complications. Using an easy-to-use model, identification, and stratification of individualized risk factors could help to identify the need for interventions and, thus, improve patient eligibility and transplant outcomes. This could also contribute to maintaining an approach with high ethical standards.

Exploring the nexus: The place of kidney diseases within the cardiovascular-kidney-metabolic syndrome spectrum

Cardiovascular-kidney-metabolic (CKM) syndrome and chronic kidney disease (CKD) are two significant comorbidities affecting a large proportion of the general population with considerable crosstalk. In addition to substantial co-incidence of CKD and CKM syndrome in epidemiological studies, clinical and pre-clinical studies have identified similar pathophysiological pathways leading to both entities. Patients with CKM syndrome are more prone to develop acute kidney injury and CKD, while therapeutic alternatives and their success rates are considerably lower in such patient groups. Nevertheless, the association between CKM syndrome and CKD or ESKD is bidirectional rather than being a cause-effect relationship as patients with CKD are also prone to develop peripheral insulin resistance, high blood pressure, and dyslipidemia. Furthermore, such patients are less likely to receive kidney transplantation in addition to the higher allograft dysfunction risk. We hereby aim to evaluate the association in-between kidney diseases and CKM syndrome, including epidemiological data, pre-clinical studies with pathophysiological pathways, and potential therapeutic perspectives.

The use of semaglutide in patients with renal failure- a retrospective cohort study

OBJECTIVE

Semaglutide, a glucagon-like peptide-1 receptor agonist is approved for weight loss and diabetes treatment, but limited literature exists regarding semaglutide use in patients with advanced chronic kidney disease (CKD). Therefore, this project assessed the safety and efficacy of semaglutide among patients with eGFR (estimated glomerular filtration rate) 15-29 mL/min/1.73m2 (CKD stage 4), eGFR<15 mL/min/1.73m2 (CKD stage 5) or on dialysis.

METHODS

This is a retrospective Electronic Medical Record based analysis of consecutive patients with advanced CKD (defined as CKD 4 or greater) who were started on semaglutide (injectable or oral). Data was collected between Jan 2018 and Jan 2023. Investigators verified CKD diagnosis and manually extracted data. Data were analyzed using Fisher's exact test, paired T-test, linear mixed effects models and Wilcoxon signed rank test.

RESULTS

Seventy-six patients with CKD 4 or greater who initiated semaglutide were included. Most patients had a history of T2DM (96.0%), and most were male (53.9%). The mean age was 66.8 y (SD 11.5) with the mean BMI was 36.2 (SD 7.5). The initial doses were 3 mg orally and 0.25 mg by injection. Maximum prescribed dose was 1mg (injectable) in 28 (45.2%) patients and 14 mg (orally) in 2 (14.2%) patients. Patients received semaglutide for a median duration of 17.4 (IQR 0.43, 48.8) months. Forty-eight (63.1%) patients reported no adverse effects associated with the therapy. Mean weight decreased from 106.2(SD 24.2) to 101.3 (SD 27.3) kg (p<0.001). Eight patients (16%) with type 2 diabetes (T2DM) discontinued insulin after starting semaglutide. Mean HbA1c decreased from 8.0 % (SD 1.7) to 7.1 % (SD 1.3) (p<0.001). Adverse effects were the primary reason for semaglutide discontinuation (37.0%), with nausea, vomiting, and abdominal pain being the most common complaints.

CONCLUSIONS

Based on this retrospective study semaglutide appears to be tolerated by most individuals with CKD 4 or greater despite associated gastrointestinal side effects similar to those observed in patients with better kidney function and leads to an improvement of glycemic control and insulin discontinuation in patients with T2DM. Modest weight loss (approximately 4.6 % of the total body weight) was observed on the prescribed doses. Larger prospective randomized studies are needed to comprehensively assess the risks and benefits of semaglutide in patients with CKD 4 or greater and obesity.

Single-center retrospective assessment of robotic-assisted simultaneous pancreas-kidney transplants: Exploring clinical utility

The diabetic population is witnessing a rise in obesity rates, creating specific hurdles for individuals seeking pancreas transplantation because they are frequently disqualified due to their elevated body weight. Introducing a robotic-assisted approach to transplantation has been proven to yield improved outcomes, particularly in patients with obesity. A retrospective analysis was conducted between January 2015 and September 2023. The study included a total of 140 patients, with 16 receiving robotic-assisted simultaneous pancreas-kidney transplantation (RSPK) and 124 undergoing open approach simultaneous pancreas-kidney transplantation (OSPK) during the study period. The median age was 45 (36.8-52.7) and 44.5 years (36.8-51.8) (RSPK vs OSPK, P = .487). There were no significant differences in demographics except body mass index (RSPK vs OSPK, 34.9 vs 28.1, P < .001) and a higher percentage of patients with high cardiac risk in the RSPK group. The robotic approach has a lengthier overall operative time and warm ischemia time. Surgical and nonsurgical complications at 30-days and 1-year grafts and patient survival (93.8% vs 96.8%, RSPK vs OSPK, P = .521) were similar. Our findings suggest that employing robotic assistance in simultaneous pancreas-kidney transplantation is safe. Wider adoption and utilization of this technique could potentially improve transplant accessibility for individuals with obesity and diabetes.

Impact of early surgical complications on kidney transplant outcomes

BACKGROUND

Kidney transplantation (KT) improves clinical outcomes of patients with end stage renal disease. Little has been reported on the impact of early post-operative surgical complications (SC) on long-term clinical outcomes following KT. We sought to determine the impact of vascular complications, urological complications, surgical site complications, and peri-graft collections within 30 days of transplantation on patient survival, graft function, and hospital readmissions.

METHODS

We conducted a single-centre, observational cohort study examining adult patients (≥ 18 years) who received a kidney transplant from living and deceased donors between January 1st, 2005 and December 31st, 2015 with follow-up until December 31st, 2016 (n = 1,334). Univariable and multivariable analyses were performed with Cox proportional hazards models to analyze the outcomes of SC in the early post-operative period after KT.

RESULTS

The cumulative probability of SC within 30 days of transplant was 25%, the most common SC being peri-graft collections (66.8%). Multivariable analyses showed significant relationships between Clavien Grade 1 SC and death with graft function (HR 1.78 [95% CI: 1.11, 2.86]), and between Clavien Grades 3 to 4 and hospital readmissions (HR 1.95 [95% CI: 1.37, 2.77]).

CONCLUSIONS

Early SC following KT are common and have a significant influence on long-term patient outcomes.

Abdominal computed tomography measurements of body composition and waitlist mortality in kidney transplant candidates

Body mass index is often used to determine kidney transplant (KT) candidacy. However, this measure of body composition (BC) has several limitations, including the inability to accurately capture dry weight. Objective computed tomography (CT)-based measures may improve pre-KT risk stratification and capture physiological aging more accurately. We quantified the association between CT-based BC measurements and waitlist mortality in a retrospective study of 828 KT candidates (2010-2022) with clinically obtained CT scans using adjusted competing risk regression. In total, 42.5% of candidates had myopenia, 11.4% had myopenic obesity (MO), 68.8% had myosteatosis, 24.8% had sarcopenia (probable = 11.2%, confirmed = 10.5%, and severe = 3.1%), and 8.6% had sarcopenic obesity. Myopenia, MO, and sarcopenic obesity were not associated with mortality. Patients with myosteatosis (adjusted subhazard ratio [aSHR] = 1.62, 95% confidence interval [CI]: 1.07-2.45; after confounder adjustment) or sarcopenia (probable: aSHR = 1.78, 95% CI: 1.10-2.88; confirmed: aSHR = 1.68, 95% CI: 1.01-2.82; and severe: aSHR = 2.51, 95% CI: 1.12-5.66; after full adjustment) were at increased risk of mortality. When stratified by age, MO (aSHR = 2.21, 95% CI: 1.28-3.83; P interaction = .005) and myosteatosis (aSHR = 1.95, 95% CI: 1.18-3.21; P interaction = .038) were associated with elevated risk only among candidates <65 years. MO was only associated with waitlist mortality among frail candidates (adjusted hazard ratio = 2.54, 95% CI: 1.28-5.05; P interaction = .021). Transplant centers should consider using BC metrics in addition to body mass index when a CT scan is available to improve pre-KT risk stratification at KT evaluation.

Does obesity really affect renal transplantation outcomes?

INTRODUCTION

Kidney transplantation is the treatment of choice for patients with stage 5 chronic kidney disease (CKD). About 60% of CKD patients are overweight or obese at the time of kidney transplantation, and post-transplant obesity occurs in 50% of patients, with a weight gain of 10% in the first year and high risk of cardiovascular mortality. Obesity is associated with an increased risk of delayed graft function (DGF), acute rejection, surgical complications, graft loss and mortality. The aim of this study is to assess the clinical evolution of obese and overweight patients that have received a kidney transplant, based on short- and long-term complications associated with a higher BMI.

MATERIAL AND METHODS

A descriptive, observational, cross-sectional study was conducted with 104 kidney or pancreas-kidney transplant patients between March 2017 and December 2020, with a follow-up until April 2021. For comparative analysis, patients were grouped according to BMI.

RESULTS

Mean age was of 56.65 years, 60.6% male and 39.4 % female. Overweight patients experienced prolonged surgeries, more surgical wound dehiscence, delayed graft function, hernias, proteinuria and more indications for renal biopsies. Additionally, obese patients displayed more DGF, indications for renal biopsies, proteinuria, development of diabetes mellitus, atrial fibrillation and needed prolonged hospital stays.

CONCLUSIONS

Despite a high prevalence of comorbidity in the overweight and/or obese population, we found no reduction in patient and/or graft survival. However, longer follow-up is needed.

Prospective evaluation of a closed-incision negative pressure wound therapy system in kidney transplantation and its association with wound complications

Introduction

Wound complications can cause considerable morbidity in kidney transplantation. Closed-incision negative pressure wound therapy (ciNPWT) systems have been efficacious in reducing wound complications across surgical specialties. The aims of this study were to evaluate the use of ciNPWT, Prevena™, in kidney transplant recipients and to determine any association with wound complications.

Material and methods

A single-center, prospective observational cohort study was performed in 2018. A total of 30 consecutive kidney transplant recipients deemed at high risk for wound complications received ciNPWT, and the results were compared to those of a historical cohort of subjects who received conventional dressings. Analysis for recipients with obesity and propensity score matching were performed.

Results

In total, 127 subjects were included in the analysis. Of these, 30 received a ciNPWT dressing and were compared with 97 subjects from a non-study historical control group who had conventional dressing. The overall wound complication rate was 21.3% (27/127). There was no reduction in the rate of wound complications with ciNPWT when compared with conventional dressing [23.3% (7/30) and 20.6% (20/97), respectively, p = 0.75]. In the obese subset (BMI ≥30 kg/m2), there was no significant reduction in wound complications [31.1% (5/16) and 36.8% (7/19), respectively, p = 0.73]. Propensity score matching yielded 26 matched pairs with equivalent rates of wound complications (23.1%, 6/26).

Conclusion

This is the first reported cohort study evaluating the use of ciNPWT in kidney transplantation. While ciNPWT is safe and well tolerated, it is not associated with a statistically significant reduction in wound complications when compared to conventional dressing. The findings from this study will be used to inform future studies associated with ciNPWT in kidney transplantation.

Bariatric Surgery as a Bridge to Facilitate Renal Transplantation in Patients with End-Stage Renal Disease

PURPOSE

Renal transplantation (RT) is not recommended above BMI 40 kg/m2 as post-operative risks (delayed graft function, wound complications) are increased. Bariatric surgery (BS) results in sustained long-term weight loss. However, renal failure (RF) patients are theoretically higher risk candidates. We aim to investigate the safety of BS in patients with RF and the effect of BS on access to renal transplantation.

METHODS

We reviewed data from 31 patients with RF referred for BS between 2013 and 2021. We compared the outcomes of patients with RF who underwent BS to those who were referred but did not undergo BS. Controls matched for age/BMI/comorbidity (MC) but without RF were used for comparison.

RESULTS

Of 31 patients referred, 19 proceeded with BS (68% female, median age 52 years, BMI 46.2 ± 4.9 kg/m2) and 12 did not (58% female, median age 58, mean BMI 41.5 ± 4.1). Excess body weight loss (EBWL) was 71.2% ± 20.2% at 2 years in RF patients versus 66.0% ± 28.0% in MC patients. In the operated group, 11/19 (58%) patients reached their treatment target (six transplanted, five placed on waiting list) versus 3/12 (25%) in unoperated patients (three transplanted). There was no difference in perioperative complications between RF and MC groups. Long-term, there were seven deaths amongst RF patients (two operated, five unoperated), none amongst the MC group.

CONCLUSION

BS in patients with RF increased access to RT and was safe and effective. We therefore recommend consideration of BS in patients with obesity and RF in specialised units.

Living donor robotic-assisted kidney transplant compared to traditional living donor open kidney transplant. Where do we stand now? A systematic review and meta-analysis

BACKGROUND

Renal transplant is the standard of care for patients with end-stage renal disease (ESRD). Robotic-assisted kidney transplant (RAKT) has emerged as a safe minimally invasive approach with a lower complication rate than open kidney transplant (OKT). Concerns regarding ischemia times and graft function are still a matter of debate.

METHODS

Following PRISMA guidelines and PROSPERO registration CRD42023413774, a systematic review was performed in March 2023 on RAKT compared to OKT. Primary outcomes of interest were surgical times, ischemia times, blood loss, complication rates, and graft function. Data were analyzed using R version 4.2.2.

RESULTS

A total of nine studies comparing living donor RAKT to living donor OKT were included, totaling 1477 patients, out of which 508 underwent RAKT and 969 OKT. RAKT cases were highly selected as depicted in the manuscript. Cumulative analysis showed significantly longer total ischemic time (MD = 16.51; 95% CI = [9.86-23.16]) and rewarming ischemia time (MD = 11.24; 95% CI = [-0.46-22.01]) in RAKT group. No differences were found in total procedure time and time to complete anastomoses. Blood loss and transfusion rate were lower in RAKT group (MD = -53.68; 95% CI = [-89.78; -17.58]) and (RR = 0.29; 95% CI = [0.14; 0.57]), respectively. The meta-analysis revealed a lower rate of surgical site infection (SSI) (RR = 0.31; 95% CI = [0.19-0.52]) and symptomatic lymphocele (RR = 0.16; 95% CI = [0.06-0.43]) in RAKT. No difference in ileus rate was found. Pain scores were significantly lower in the RAKT group (MD = -1.14; 95% CI = [-1.59 - -0.69]; p ≤0.01). No difference in length of stay and hospital readmission were evidenced. Delayed graft function (DGF) and acute rejection rates were not different between interventions groups (RR =1.23; 95% CI = [0.40-3.74]) and (RR =0.96; 95% CI = [0.55-1.70]), respectively. No difference between groups in early graft outcomes are evident.

CONCLUSIONS

Our analysis suggests that RAKT is a minimally invasive, safe, and feasible procedure. It is associated with a lower complication rate and similar intraoperative, perioperative, and postoperative outcomes. Further quality studies are needed to confirm these findings.

Incomplete Data and Potential Risks of Drugs in People with Obesity

PURPOSE OF REVIEW

To provide examples of knowledge gaps in current pharmaceutical treatments for people with obesity and call for changes to regulatory and pharmaceutical clinical research requirements during the drug discovery and development process.

RECENT FINDINGS

Treatment of obesity and its comorbidities often require the use of prescription drugs, many of which have not been fully evaluated in people with obesity. Despite a growing body of research on this topic, the impact of obesity on the pharmacokinetics and pharmacodynamics of drugs is often under-studied by drug sponsors and regulators, and subsequently underappreciated by clinicians and caretakers. There are currently multiple opportunities for pharmaceuticals to include dosing information specifically for patients with obesity in order to ensure safety and efficacy of drugs in this population. Additionally, there are serious gaps between what is known about the effects of obesity on drug disposition and the current use of drugs according to drug prescribing information and clinical practice. There is currently no requirement to test drugs in people with obesity during the drug approval process, even when preliminary data suggests there may be altered kinetics in this population. The lack of information on the safe and effective use of drugs in people with obesity may be contributing to poorer health outcomes in this population.

Obesity and Kidney Transplantation-How to Evaluate, What to Do, and Outcomes

Obesity is a growing issue that is spreading worldwide; its prevalence is ever increasing in patients with end-stage renal disease and represents a potential barrier to transplantation. The lack of unanimous guidelines exacerbates the current disparity in treatment, which can affect outcomes, leading to a significantly longer time on the waiting list. Multidisciplinary and multimodal management (encompassing several healthcare professionals such as nephrologists, transplant physicians and surgeons, primary care providers, and nurses) is of paramount importance for the optimal management of this patient population in a continuum from waitlisting to transplantation. Development of this guideline followed a standardized protocol for evidence review. In this review, we report on our clinical experience in transplantation of obese patients; strategies to manage this condition, including bariatric surgery, suitable timing for transplantation among this patient population, and clinical experience in robotic sleeve gastrectomy; and simultaneous robotic kidney transplantation to achieve optimal outcomes.

Using Machine Learning to Predict Surgical Site Infection After Lumbar Spine Surgery

Objective

The objective of this study was to utilize machine learning techniques to analyze perioperative factors and identify blood glucose levels that can predict the occurrence of surgical site infection following posterior lumbar spinal surgery.

Methods

A total of 4019 patients receiving lumbar internal fixation surgery from an institute were enrolled between June 2012 and February 2021. First, the filtered data were randomized into the test and verification groups. Second, in the test group, specific variables were screened using logistic regression analysis, Lasso regression analysis, support vector machine, and random forest. Specific variables obtained using the four methods were intersected, and a dynamic model was constructed. ROC and calibration curves were constructed to assess model performance. Finally, internal model performance was verified in the verification group using ROC and calibration curves.

Results

The data from 4019 patients were collected. In total, 1327 eligible cases were selected. By combining logistic regression analysis with three machine learning algorithms, this study identified four predictors associated with SSI, namely Modic changes, sebum thickness, hemoglobin, and glucose. Using this information, a prediction model was developed and visually represented. Then, we constructed ROC and calibration curves using the test group; the area under the ROC curve was 0.988. Further, calibration curve analysis revealed favorable consistency of nomogram-predicted values compared with real measurements. The C-index of our model was 0.986 (95% CI 0.981-0.994). Finally, we used the validation group to validate the model internally; the AUC was 0.987. Calibration curve analysis revealed favorable consistency of nomogram-predicted values compared with real measurements. The C-index was 0.982 (95% CI 0.974-0.999).

Conclusion

Logistic regression analysis and machine learning were employed to select four risk factors: Modic changes, sebum thickness, hemoglobin, and glucose. Then, a dynamic prediction model was constructed to help clinicians simplify the monitoring and prevention of SSI.

Recipient race modifies the association between obesity and long-term graft outcomes after kidney transplantation

Donor and recipient obesity (defined using body mass index [BMI]) are associated with worse outcomes after kidney transplant (KT). In adult KT recipients identified using the Scientific Registry of Transplant Recipients (2000-2017), we examined the modifying effect of recipient race on recipient obesity (BMI > 30 kg/m2) and combined donor and recipient (DR) obesity pairing, with death-censored graft loss (DCGL), all-cause graft loss (ACGL), and short-term graft outcomes using multivariable Cox proportional hazards models and logistic regression. Obesity was associated with a higher risk of DCGL in White (adjusted hazard ratio [aHR], 1.29; 95% CI, 1.25-1.35) than Black (aHR, 1.13; 95% CI, 1.08-1.19) recipients. White, but not Black, recipients with obesity were at higher risk for ACGL (aHR, 1.08; 95% CI, 1.05-1.11, for White recipients; aHR, 0.99; 95% CI, 0.95-1.02, for Black recipients). Relative to nonobese DR, White recipients with combined DR obesity experienced more DCGL (aHR, 1.38; 95% CI, 1.29-1.47 for White; aHR, 1.19; 95% CI, 1.10-1.29 for Black) and ACGL (aHR, 1.12; 95% CI, 1.07-1.17 for White; aHR, 1.00; 95% CI, 0.94-1.07 for Black) than Black recipients. Short-term obesity risk was similar irrespective of race. An elevated BMI differentially affects long-term outcomes in Black and White KT recipients; uniform BMI thresholds to define transplant eligibility are likely inappropriate.

Wound related complications and the anterior rectus sheath versus Gibson approach to kidney transplantation: A single center randomized controlled trial

INTRODUCTION

Wound related complications (WRC) are a significant source of morbidity in kidney transplant recipients, and may be mitigated by surgical approach. We hypothesize that the anterior rectus sheath approach (ARS) may decrease WRC and inpatient opiate use compared to the Gibson Approach (GA).

METHODS

This double-blinded randomized controlled trial allocated kidney transplant recipients aged 18 or older, exclusive of other procedures, 1:1 to ARS or GA at a single hospital. The ARS involves a muscle-splitting paramedian approach to the iliopsoas fossa, compared to the muscle-cutting GA. Patients and data analysts were blinded to randomization.

RESULTS

Seventy five patients were randomized to each group between August 27, 2019 and September 18, 2020 with a minimum 12 month follow-up. There was no difference in WRC between groups (p = .23). Nine (12%) and three patients (4%) experienced any WRC in the ARS and GA groups, respectively. Three and one Clavien IIIb complications occurred in the ARS and GA groups, respectively. In a multiple linear regression model, ARS was associated with decreased inpatient opioid use (β = -58, 95% CI: -105 to -12, p = .016).

CONCLUSIONS

The ARS did not provide a WRC benefit in kidney transplant recipients, but may be associated with decreased inpatient opioid use.

Single-Port Robotic Applications in Urology

Objective: The da Vinci single-port (SP) platform represents the latest innovation in minimally invasive urologic surgery, and the adoption of this technology by urologists is increasing. In this article, we briefly describe the evolution of minimally invasive and single-site surgery, and offer a comprehensive review of the current literature on the SP platform. Materials and Methods: For relevant articles, three electronic databases, including PubMed, Scopus, and Web of Science, were searched from their inception until August 15, 2022. The published literature to date within SP robotic surgery in urology will be discussed. Evidence Synthesis: There are relatively few high-quality studies on the SP system, but there are multiple case series describing unique indications and surgical approaches with the SP robot, demonstrating safety and feasibility in the hands of experienced robotic surgeons. There also are an increasing number of prospective, larger cohort studies comparing outcomes between SP and multiport (MP) approaches that show benefits of the SP system regarding improved cosmesis, postoperative pain control, and decreased length of stay. Conclusions: Multiple prospective studies have shown benefits regarding cost and pain control for SP platform procedures compared to the traditional MP robotic approach. While its high cost and learning curve represent barriers to adoption, the SP platform represents a critical development in minimally invasive surgery. As this technology is further implemented at more institutions, long-term, high-quality data should accrue that will demonstrate its true value.

Transplanting a left or right donor kidney into the left or right iliac fossa: importance of laterality and site of venous anastomosis

Data on the impact of donor-to-recipient laterality on kidney transplantation are lacking. This study evaluated the impact of donor-to-iliac fossa laterality and the site of venous anastomosis on operating time and surgical outcome. This retrospective single-center study analyzed 1262 deceased donor adult kidney transplants into pristine iliac fossa. Multivariable linear and logistic regression analyses were used to identify variables with an impact on operating time and surgical complications. Operating time was shorter by 11 min in median for transplantations into the right iliac fossa compared to the left iliac fossa (p < 0.001). Operating time in left-to-right donor-to-recipient combination was shorter by 17 min in median if venous anastomoses were performed on the caval vein or common iliac vein as compared to anastomoses to the external iliac vein (p < 0.001). Overall, the shortest operating times (median 112.5 min) were achieved in left-to-right donor-to-recipient combinations with venous anastomosis to the caval or common iliac vein, without an increase in surgical complications. Kidney transplantation into the right iliac fossa with anastomosis to the caval vein or the common iliac vein saves operating time and reduces thrombotic complications. Acceptance of a left donor kidney is likely to further reduce operating time.

Post-kidney transplant body mass index trajectories are associated with graft loss and mortality

BACKGROUND

Early post-kidney transplantation (KT) changes in physiology, medications, and health stressors likely impact body mass index (BMI) and likely impact all-cause graft loss and mortality.

METHODS

We estimated 5-year post-KT (n = 151 170; SRTR) BMI trajectories using an adjusted mixed effects model. We estimated long-term mortality and graft loss risks by 1-year BMI change quartile (decrease [1st quartile]: change < -.07 kg/m2 /month; stable [2nd quartile]: -.07 ≤ change ≤ .09 kg/m2 /month; increase [3rd, 4th quartile]: change > .09 kg/m2 /month) using adjusted Cox proportional hazards models.

RESULTS

BMI increased in the 3 years post-KT (.64 kg/m2 /year, 95% CI: .63, .64) and decreased in years 3-5 (-.24 kg/m2 /year, 95% CI: -.26, -.22). 1-year post-KT BMI decrease was associated with elevated risks of all-cause mortality (aHR = 1.13, 95% CI: 1.10-1.16), all-cause graft loss (aHR = 1.13, 95% CI: 1.10-1.15), death-censored graft loss (aHR = 1.15, 95% CI: 1.11-1.19), and mortality with functioning graft (aHR = 1.11, 95% CI: 1.08-1.14). Among recipients with obesity (pre-KT BMI≥30 kg/m2 ), BMI increase was associated with higher all-cause mortality (aHR = 1.09, 95% CI: 1.05-1.14), all-cause graft loss (aHR = 1.05, 95% CI: 1.01-1.09), and mortality with functioning graft (aHR = 1.10, 95% CI: 1.05-1.15) risks, but not death-censored graft loss risks, relative to stable weight. Among individuals without obesity, BMI increase was associated with lower all-cause graft loss (aHR = .97, 95% CI: .95-.99) and death-censored graft loss (aHR = .93, 95% CI: .90-.96) risks, but not all-cause mortality or mortality with functioning graft risks.

CONCLUSIONS

BMI increases in the 3 years post-KT, then decreases in years 3-5. BMI loss in all adult KT recipients and BMI gain in those with obesity should be carefully monitored post-KT.

The association of center volume with transplant outcomes in selected high-risk groups in kidney transplantation

BACKGROUND

In context of increasing complexity and risk of deceased kidney donors and transplant recipients, the impact of center volume (CV) on the outcomes of high-risk kidney transplants(KT) has not been well determined.

METHODS

We examined the association of CV and outcomes among 285 U.S. transplant centers from 2000-2016. High-risk KT were defined as recipient age ≥ 70 years, body mass index (BMI) ≥ 35 kg/m², receiving kidneys from donors with kidney donor profile index(KDPI) ≥ 85%, acute kidney injury(AKI), hepatitisC + . Average annual CV for the specific-high-risk KT categorized in tertiles. Death-Censored-Graft-Loss(DCGL) and death at 3 months, 1, 5, and 10 years were compared between CV tertiles using Cox-regression models.

RESULTS

Two hundred fifty thousand five hundred seventy-four KT were analyzed. Compared to high CV, recipients with BMI ≥ 35 kg/m² had higher risk of DCGL in low CV(aHR = 1.11,95%CI = 1.03-1.19) at 10 years; recipients with age ≥ 70 years had higher risk of death in low CV(aHR = 1.07,95%CI = 1.01-14) at 10 years. There was no difference of DCGL or death in low CV for donors with KDPI ≥ 85%, hepatitisC + , or AKI.

CONCLUSIONS

Recipients of high-risk KT with BMI ≥ 35 kg/m² have higher risk of DCGL and recipients age ≥ 70 years have higher risk of death in low CV, compared to high CV. Future studies should identify care practices associated with CV that support optimal outcomes after KT.

Retrospective analysis of the impact of severe obesity on kidney transplant outcomes

BACKGROUND

The prevalence of obesity among kidney transplant recipients is rising. We sought to determine the association between recipient body mass index (BMI) and post-transplant complications.

METHODS

Single-center, retrospective cohort study of all adult kidney transplant recipients from 2004 to 2020. Recipients were stratified into four BMI categories: normal-weight (BMI 18.5-24.9 kg/m2, n = 1020), overweight (BMI 25-29.9 kg/m2, n = 1002), moderately obese (BMI 30-34.9 kg/m2, n = 510) and severely-to-morbidly obese (BMI ≥35 kg/m2, n = 274). Logistic regression was used to estimate the association between BMI category and surgical site infections (SSIs).

RESULTS

Recipients with BMI ≥35 kg/m2 had significantly higher rates of SSIs (P < .0001) compared with recipients in all other categories. On multivariable analysis, recipients with BMI ≥35 kg/m2 had increased odds of SSIs compared with normal-weight recipients [odds ratio (OR) 3.34, 95% confidence interval (CI) 1.55-7.22, P = .022). On multivariable and Kaplan-Meier analyses, no BMI groups demonstrated increased odds for death-censored graft failure.

CONCLUSION

Severe obesity in kidney transplant recipients is associated with increased SSIs, but not kidney allograft failure.

Outcomes of kidney transplant recipients who underwent pre-transplant bariatric surgery for severe obesity: a long-term follow-up study

BACKGROUND

Kidney transplantation (KT) is the preferred therapy for end-stage renal disease (ESRD). While a major cause for ESRD, obesity is also a key obstacle to candidacy for KT. Bariatric surgery, particularly sleeve gastrectomy (SG), is increasingly used to improve access to KT in patients with obesity, but the literature especially on outcomes post-KT remains lacking. We aimed to provide a long-term follow-up analysis of efficacy and outcomes of a previously described cohort of patients with obesity, who had SG as a means for access to KT.

METHODS

This is a single-center retrospective follow-up study of 32 patients with advanced chronic kidney disease or ESRD, who were referred and underwent SG between 2013 and 2018 as an access strategy to KT. The primary outcome was successful KT. Ninety-day outcomes, long-term graft function, and changes in weight and obesity-related comorbidities after KT were assessed. Descriptive statistics are presented as count (percentage) or median (interquartile range).

RESULTS

At baseline, 18 (56%) were male with a median age and BMI of 51 (11) years and 42.3 (5.2) kg/m², respectively. Median follow-up time post-SG was 53 (58) months. At last follow-up, 23 (72%) patients received KT. Median time to KT was 16 (20) months and BMI was 34.0 (5.1) kg/m² at time of transplant. At KT, 13 (57%) and 20 (87%) had diabetes and hypertension, respectively. Median follow-up post-KT was 16 (47) months. There was one graft loss requiring return to dialysis. At 5-year post-KT, median serum creatinine was 136 (66) µmol/l. At last follow-up post-KT, median BMI remained at 33.7 (7.6) kg/m². Among patients with diabetes and hypertension, 7/13 (54%) and 5/20 (25%) had either improvement or remission of their comorbidities, respectively.

CONCLUSION

SG is an effective strategy to improve access to KT in patients with severe obesity. Transplant recipients also continue to benefit from sustained weight loss and improved related comorbidities that may positively impact their graft function after KT.

Combined Donor-Recipient Obesity and the Risk of Graft Loss After Kidney Transplantation

Background: As the prevalence of obesity increases globally, appreciating the effect of donor and recipient (DR) obesity on graft outcomes is of increasing importance.

Methods: In a cohort of adult, kidney transplant recipients (2000–2017) identified using the SRTR, we used Cox proportional hazards models to examine the association between DR obesity pairing (body mass index (BMI) &gt;30 kg/m2), and death-censored graft loss (DCGL) or all-cause graft loss, and logistic regression to examine risk of delayed graft function (DGF) and ≤30 days graft loss. We also explored the association of DR weight mismatch (&gt;30 kg, 10-30 kg (D&gt;R; D&lt;R) and &lt;10 kg (D = R)) with each outcome, stratifying by DR obesity pairing.

Results: Relative to non-obese DR, obese DR were highest risk for all outcomes (DCGL: HR 1.26, 95% CI 1.22–1.32; all-cause graft loss: HR 1.09, 95% CI 1.06–1.12; DGF: OR 1.98, 95% CI 1.89–2.08; early graft loss: OR 1.34, 95% CI 1.19–1.51). Donor obesity modified the risk of recipient obesity and DCGL [p = 0.001] and all-cause graft loss [p &lt; 0.001] but not DGF or early graft loss. The known association of DR weight mismatch with DCGL was attenuated when either the donor or recipient was obese.

Conclusion: DR obesity status impacts early and late post-transplant outcomes.

Guiding Kidney Transplantation Candidates for Effective Weight Loss: A Clinical Cohort Study

BACKGROUND

Obesity is increasingly common in kidney transplant candidates and may limit access to transplantation. Obesity and diabetes are associated with a high risk for post-transplant complications. The best approach to weight loss to facilitate active transplant listing is unknown, but bariatric surgery is rarely considered due to patient- and physician-related apprehension, among other factors.

METHODS

We aimed to determine the magnitude of weight loss, listing, and transplant rates in 28 candidates with a mean BMI of 44.4±4.6 kg/m² and diabetes treated conservatively for 1 year post weight-loss consultations (group 1). Additionally, we evaluated 15 patients (group 2) who met the inclusion criteria but received bariatric intervention within the same time frame. All patients completed a multidisciplinary weight management consultation with at least 1 year of follow-up.

RESULTS

In the conservatively managed group (group 1), the mean weight at the time of initial consultation was 126.5±18.5 kg, and the mean BMI was 44.4±4.6 kg/m². At 1 year post weight-loss consultation, the mean weight decreased by 4.4±8.2 kg to 122.9±17 kg, and the mean BMI was 43±4.8 kg/m², with a total mean body weight decrease of 3% (P=0.01). Eighteen patients (64%) did not progress to become candidates for active listing/transplantation during the follow-up time of 4±2.9 years, with 15 (54%) subsequently developing renal failure/diabetes-related comorbidities prohibitive for transplantation. In contrast, mean total body weight decreased by 19% at 6 months post bariatric surgery, and the mean BMI was 34.2±4 and 32.5±3.7 kg/m² at 6 and 12 months, respectively. Bariatric surgery was strongly associated with subsequent kidney transplantation (HR=8.39 [95% CI 1.71 to 41.19]; P=0.009).

CONCLUSIONS

A conservative weight-loss approach involving multidisciplinary consultation was ineffective in most kidney transplant candidates with diabetes, suggesting that a more proactive approach is needed.

Simultaneous Robotic-Assisted Bilateral Native Nephrectomy and Kidney Transplantation for Autosomal Dominant Polycystic Kidney Disease in Recipients With High Body Mass Index: Report of 2 Cases

Robotic kidney transplantation is a safe, reproducible, and less morbid technique in high body mass index and end-stage renal disease. Polycystic kidney disease is a relative contraindication to robotic-assisted kidney transplantation because of the mass effect of the native kidneys on the patient's pelvis that prevents ideal exposure. We report the first 2 cases of robotic-assisted simultaneous bilateral nephrectomy and kidney transplantation for patients with obesity and adult polycystic kidney disease. The recipients were 2 males, 50 and 53 years old, with a body mass index of 35.1 41.6 kg/m² and 41.6 kg/m², respectively. Both recipients had suitable living donors. The average operating time was 395 minutes and the estimated blood loss was on average 250 mL. The postoperative course was uneventful and the patients were discharged home on days 4 and 5. Performing robotic nephrectomies simultaneously with kidney transplantation can be done safely, allowing patients with obesity and polycystic kidney disease needing bilateral nephrectomy, to take full advantage of minimally invasive kidney transplantation.

Prophylactic Cefazolin Dosing in Obesity-a Systematic Review

Currently, there is no consensus on whether a standard 2-g prophylactic cefazolin dose provides sufficient antimicrobial coverage in obese surgical patients. This systematic review analysed both outcome and pharmacokinetic studies, aiming to determine the appropriate cefazolin dose. A systematic search was conducted using 4 databases. In total, 3 outcome and 15 pharmacokinetic studies met the inclusion criteria. All 3 outcome studies concluded that there is no need for increased dose. Also, 9 pharmacokinetic studies reached this conclusion; however, 6 pharmacokinetic studies recommended that 2-g dose is insufficient to achieve adequate plasma or tissue concentrations. The stronger body of evidence supports that 2-g dose of cefazolin is sufficient for surgery lasting up to 4 h; however, large-scale outcome studies are needed to confirm this evidence.

Kidney Retransplantation after Graft Failure: Variables Influencing Long-Term Survival

Background

There is an increasing demand for kidney retransplantation. Most studies report inferior outcomes compared to primary transplantation, consequently feeding an ethical dilemma in the context of chronic organ shortage.

Objective

To assess variables influencing long-term graft survival after kidney retransplantation. Material and Methods. All patients transplanted at our center between 2000 and 2016 were analyzed retrospectively. Survival was estimated with the Kaplan–Meier method, and risk factors were identified using multiple Cox regression.

Results

We performed 1,376 primary kidney transplantations and 222 retransplantations. The rate of retransplantation was 67.8% after the first graft loss, with a comparable 10-year graft survival compared to primary transplantation (67% vs. 64%, p=0.104) but an inferior graft survival thereafter (log-rank p=0.026). Independent risk factors for graft survival in retransplantation were age ≥ 50 years, time on dialysis ≥1 year, previous graft survival <2 years, ≥1 mild comorbidity in the Charlson–Deyo index, active smoking, and life-threatening complications (Clavien–Dindo grade IV) at first transplantation.

Conclusion

Graft survival is comparable for first and second kidney transplantation within the first 10 years. Risk factors for poor outcomes after retransplantation are previous graft survival, dialysis time after graft failure, recipient age, comorbidities, and smoking. Patients with transplant failure should have access to retransplantation as early as possible.

Machine Learning Consensus Clustering of Morbidly Obese Kidney Transplant Recipients in the United States

Background: This study aimed to better characterize morbidly obese kidney transplant recipients, their clinical characteristics, and outcomes by using an unsupervised machine learning approach. Methods: Consensus cluster analysis was applied to OPTN/UNOS data from 2010 to 2019 based on recipient, donor, and transplant characteristics in kidney transplant recipients with a pre-transplant BMI ≥ 40 kg/m2. Key cluster characteristics were identified using the standardized mean difference. Post-transplant outcomes, including death-censored graft failure, patient death, and acute allograft rejection, were compared among the clusters. Results: Consensus clustering analysis identified 3204 kidney transplant recipients with a BMI ≥ 40 kg/m2. In this cohort, five clinically distinct clusters were identified. Cluster 1 recipients were predominantly white and non-sensitized, had a short dialysis time or were preemptive, and were more likely to receive living donor kidney transplants. Cluster 2 recipients were older and diabetic. They were likely to have been on dialysis >3 years and receive a standard KDPI deceased donor kidney. Cluster 3 recipients were young, black, and had kidney disease secondary to hypertension or glomerular disease. Cluster 3 recipients had >3 years of dialysis and received non-ECD, young, deceased donor kidney transplants with a KDPI < 85%. Cluster 4 recipients were diabetic with variable dialysis duration who either received non-ECD standard KDPI kidneys or living donor kidney transplants. Cluster 5 recipients were young retransplants that were sensitized. One-year patient survival in clusters 1, 2, 3, 4, and 5 was 98.0%, 94.4%, 98.5%, 98.7%, and 97%, and one-year death-censored graft survival was 98.1%, 93.0%, 96.1%, 98.8%, and 93.0%, respectively. Cluster 2 had the worst one-year patient survival. Clusters 2 and 5 had the worst one-year death-censored graft survival. Conclusions: With the application of unsupervised machine learning, variable post-transplant outcomes are observed among morbidly obese kidney transplant recipients. Recipients with earlier access to transplant and living donation show superior outcomes. Unexpectedly, reduced graft survival in cluster 3 recipients perhaps underscores socioeconomic access to post-transplant support and minorities being disadvantaged in access to preemptive and living donor transplants. Despite obesity-related concerns, one-year patient and graft survival were favorable in all clusters, and obesity itself should be reconsidered as a hard barrier to kidney transplantation.

Single-center experience with perioperative antibiotic prophylaxis and surgical site infections in kidney transplant recipients

Background

Infections in kidney transplant recipients are particularly challenging owing to the immunosuppressive treatment, usually long history of chronic illness, comorbidities and prior exposures to antibiotics. Among the most common complications early after surgery are surgical site infections. The aim of this study was to identify risk factors and evaluate epidemiological data regarding surgical site infections. Moreover, we were able to compare the current results with historical data from our institution when different perioperative antibiotic prophylaxis was practiced.

Methods

We conducted a retrospective case–control study in a group of 254 deceased donor renal graft recipients transplanted in a single Central European institution. We evaluated epidemiological findings and resistance patterns of pathogens causing surgical site infections. We used multivariable logistic regression to determine risk factors for surgical site infections.

Results

We revealed no differences in baseline characteristics between patients with and without surgical site infections. Ten surgical site infections (3.9%) were diagnosed (six superficial incisional, two deep incisional, and two organ/space). Eight species (19 strains) were identified, most of which were multi-drug resistant (63%). The most common was extended-spectrum β-lactamase producing Klebsiella pneumoniae (26%). We showed that statistically significant differences were present between reoperated and non-reoperated patients (adjusted odds ratio: 6.963, 95% confidence interval 1.523–31.842, P = .012).

Conclusions

Reoperation is an individual risk factor for surgical site infection after kidney transplantation. According to our experience, cefazolin-based prophylaxis can be safe and is associated with relatively low prevalence of surgical site infections.

Robot-assisted kidney transplantation as a minimally invasive approach for kidney transplant recipients: A systematic review and meta-analyses

BACKGROUND

Robot-assisted kidney transplantation (RAKT) has emerged as an alternative for kidney transplant recipients with the potential benefits of minimally invasive surgery. The aim of this systematic review and meta-analysis is to compare the clinical outcomes of RAKT with open kidney transplantation (OKT).

METHODS

MEDLINE, Embase, Web of Science and Cochrane databases were systematically searched. Baseline characteristics, intraoperative and postoperative outcomes were collected, as well as long-term renal function and data on graft and patient survival.

RESULTS

Eleven studies were included, which compared 482 RAKT procedures with 1316 OKT procedures. RAKT was associated with lower a risk of surgical site infection (Risk ratio (RR) = 0.15, p < 0.001), symptomatic lymphocele (RR = 0.20, p = 0.03), less postoperative pain (Mean difference (MD) = -1.38 points, p < 0.001), smaller incision length (MD = -8.51 cm, p < 0.001), and shorter length of hospital stay (MD = -1.69 days, p = 0.03) compared with OKT. No difference was found in renal function, graft, and patient survival.

CONCLUSIONS

RAKT is a safe and feasible alternative to OKT with less surgical complications without compromising renal function, graft and patient survival.

Robotic Kidney Transplant: The Modern Era Technical Revolution

Since the mid 20th century, transplantation has been a fast-developing field of contemporary medicine. The technical aspects of transplant operations were developed in the 1950s, with little significant change for >50 y. Those techniques allowed completion of various organ transplants and successful patient outcomes, but they also carried the inherent disadvantages of open surgery, such as postoperative pain, wound complications and infections, and prolonged length of hospital stay. The introduction and adoption of minimally invasive surgical techniques in the early 1990s to various surgical specialties including general, gynecologic, and urologic surgery led to significant improvements in postoperative patient care and outcomes. Organ transplantation, with its precision demanding vascular anastomoses, initially had been considered infeasible to accomplish with conventional laparoscopic devices. The institution of robotic surgical technology in the late 1990s and its subsequent wide utilization in fields of surgery changed its accessibility and acceptance. With the steady camera, 3D views, and multidirectional wrist motions, surgical robotics opened new horizons for technically demanding surgeries such as transplantation to be completed in a minimally invasive fashion. Furthermore, the hope was this technique could find a niche to treat patients who otherwise are not deemed surgical candidates in many fields including transplantation. Here in, robotics in kidney transplantation and its ability to help provide equity through access to transplantation will be discussed.

Mammalian Target of Rapamycin Inhibitors and Wound Healing Complications in Kidney Transplantation: Old Myths and New Realities

Mammalian target of rapamycin inhibitors (mTOR-I) lacks nephrotoxicity, has antineoplastic effects, and reduces viral infections in kidney transplant recipients. Earlier studies reported a significant incidence of wound healing complications and lymphocele. This resulted in the uncomfortable willingness of transplant clinicians to use these agents in the immediate posttransplant period. As evidence and experience evolved over time, much useful information became available about the optimal use of these agents. Understandably, mTOR-I effects wound healing through their antiproliferative properties. However, there are a lot of other immunological and nonimmunological factors which can also contribute to wound healing complications. These risk factors include obesity, uremia, increasing age, diabetes, smoking, alcoholism, and protein-energy malnutrition. Except for age, the rest of all these risk factors are modifiable. At the same time, mycophenolic acid derivatives, steroids, and antithymocyte globulin (ATG) have also been implicated in wound healing complications. A lot has been learnt about the optimal dose of mTOR-I and their trough levels, its combinations with other immunosuppressive medications, and patients' profile, enabling clinicians to use these agents appropriately for maximum benefits. Recent randomized control trials have further increased the confidence of clinicians to use these agents in immediate posttransplant periods.

Nonlinear relationship between body mass index and clinical outcomes after kidney transplantation: A dose-response meta-analysis of 50 observational studies

BACKGROUND

Exact dose-response relationship between body mass index at transplantation and clinical outcomes after kidney transplantation remained unclear, and no specific body mass index threshold and pretransplant weight loss aim were recommended for kidney transplantation candidates among transplant centers.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library were searched for literature published up to December 31, 2019. The two-stage, random effect meta-analysis was performed to estimate the dose-response relationship between body mass index and clinical outcomes after kidney transplantation.

RESULTS

Ninety-four studies were included for qualitative assessment and 50 for dose-response meta-analyses. There was a U-shaped relationship between graft loss, patient death, and body mass index. Body mass index with the lowest risk of graft loss was 25.2 kg/m², and preferred body mass index range was 22-28 kg/m². Referring to a body mass index of 22 kg/m², the risk of graft loss was 1.088, 0.981, 1.003, and 1.685 for a body mass index of 18, 24, 28, and 40 kg/m², respectively. Body mass index with the lowest risk of patient death was 24.7 kg/m², and preferred body mass index range was 22-27 kg/m². Referring to a body mass index of 22 kg/m², the patient death risk was 1.115, 0.981, 1.032, and 2.634 for a body mass index of 18, 24, 28, and 40 kg/m², respectively. J-shaped relationships were observed between body mass index and acute rejection, delayed graft function, primary graft nonfunction, and de novo diabetes. Pair-wise comparisons showed that higher body mass index was also a risk factor for cardiovascular diseases, hypertension, infection, longer length of hospital stay, and lower estimated glomerular filtration rate level.

CONCLUSION

Underweight and severe obesity at transplantation are associated with a significantly increased risk of graft loss and patient death. A target body mass index at kidney transplantation is 22-27 kg/m².

Robot-assisted kidney transplantation: an update

Renal transplantation has become the gold-standard treatment for the majority of patients with established renal failure. Recent decades have seen significant progress in immunosuppressive therapies and advances in post-transplant management of recipients, resulting in improved graft and patient outcomes. However, the open technique of allograft implantation has stood the test of time, remaining largely unchanged. In a world where major advances in surgery have been facilitated by innovations in the fields of biotechnology and medical instrumentation, minimally invasive options have been introduced for the recipient undergoing kidney transplantation. In this review we present the evolution of minimally invasive kidney transplantation, with a specific focus on robot-assisted kidney transplant and the benefits it offers to specific patient groups. We also discuss the ethical concerns that must be addressed by transplant teams considering developing or referring to robotic programs.

Obesity Management in Kidney Transplant Candidates: Current Paradigms and Gaps in Knowledge

In this review, we discuss the increasing prevalence of obesity among people with chronic and end-stage kidney disease (ESKD) and implications for kidney transplant (KT) candidate selection and management. Although people with obesity and ESKD receive survival and quality-of-life benefits from KT, most KT programs maintain strict body mass index (BMI) cutoffs to determine transplant eligibility. However, BMI does not distinguish between visceral adiposity, which confers higher cardiovascular risks and risks of perioperative and adverse posttransplant outcomes, and muscle mass, which is protective in ESKD. Furthermore, requirements for patients with obesity to lose weight before KT should be balanced with the findings of numerous studies that show weight loss is a risk factor for death among patients with ESKD, independent of starting BMI. Data suggest that KT is associated with survival benefits relative to remaining on dialysis for candidates with obesity although recipients without obesity have higher delayed graft function rates and longer transplant hospitalization durations. Research is needed to determine the optimal body composition metrics for KT candidacy assessments and risk stratification. In addition, ESKD-specific obesity management guidelines are needed that will address the neurologic, behavioral, socioeconomic, and physical underpinnings of this increasingly common disease.

Surgical site complications in kidney transplant recipients: incidence, risk factors and outcomes in the modern era

BACKGROUND

Surgical site complications (SSCs) are an important source of morbidity after kidney transplantation. We assessed the incidence, risk factors, outcomes and economic impact of SSCs in a large, diverse population of kidney transplant recipients.

METHODS

We conducted a single-centre, observational cohort study of adult (age ≥ 18 yr) patients who underwent kidney transplantation between Jan. 1, 2005, and Dec. 31, 2015, with a minimum of 1 year of follow-up. Cases of SSC, including infections and wound dehiscence, were determined from patient records. Inpatient and outpatient hospital costs were determined 6 and 12 months after transplantation. We used the Kaplan-Meier product-limit method to determine the cumulative probability of SSCs and other outcomes. We evaluated risk factors and clinical outcomes using Cox proportional hazard ratios. Linear regression models were used to study the effect of SSCs on graft function.

RESULTS

The incidence rate of SSCs within 30 days after transplantation was 4.19 per 100 person-months. The cumulative probability of developing an SSC within 30 days after transplantation was 4.13% (95% confidence interval [CI] 3.23%-5.28%). Increased recipient body mass index (BMI) (hazard ratio [HR] 1.07, 95% CI 1.02-1.11), longer cold ischemic time (HR 1.05, 95% CI 1.01-1.09) and transplantation in 2010-2012 versus 2005-2009 (HR 2.20, 95% CI 1.19-4.04) were risk factors for SSC development. In multivariable stepwise Cox proportional hazard models, SSC was a significant risk factor for death-censored graft failure (HR 3.08, 95% CI 1.60-5.90) and total graft failure (HR 2.09, 95% CI 1.32-3.32). Cumulative median hospital costs were $2238.46 greater for patients with an SSC than for those without.

CONCLUSION

Increased BMI, longer cold ischemic time and the 2010-2012 transplantation period predisposed to SSCs. The development of SSCs was associated with a higher risk of graft failure. Strategies to minimize SSCs may improve outcomes after kidney transplantation and reduce costs.

But Why Weight: Understanding the Implications of Obesity in Kidney Transplant

Obesity is increasing in prevalence among candidates for kidney transplant. Understanding the influence of obesity on candidate evaluation, surgical risk, peritransplant management, and post-transplant outcomes is critical to ensuring equitable access to transplant for this growing population.

Robot-assisted kidney transplantation is a safe alternative approach for morbidly obese patients with end-stage renal disease

BACKGROUND

Many centres deny obese patients with a body mass index (BMI) >35 access to kidney transplantation due to increased intraoperative and postoperative complications.

METHODS

From August 2017 to December 2019, 73 consecutive cases of kidney transplantation in morbidly obese patients were enrolled at a single university at the initiation of a robotic transplant surgery program. Outcomes of patients who underwent robotic assisted kidney transplant (RAKT) were compared to frequency-matched patients undergoing open kidney transplant (OKT).

RESULTS

A total of 24 morbidly obese patients successfully underwent RAKT, and 49 obese patients received an OKT. The RAKT group developed fewer surgical site infections (SSI) than the OKT group. Graft function, creatinine, and glomerular filtration rate (GFR) were similar between groups 1 year after surgery. Graft and patient survival were 100% for both groups.

CONCLUSIONS

RAKT offers a safe alternative for morbidly obese patients, who may otherwise be denied access to OKT.

Pre-transplant morphometry by computed tomography scan and post-transplant dialysis risk in overweight or obese kidney transplant recipients

PURPOSE

Adipose distribution and sarcopenia could better assess kidney transplantation outcomes than body mass index (BMI) and have been poorly evaluated among obese and overweight recipients. We aimed to evaluate morphometric radiologic markers to predict post-operative dialysis within this population.

METHODS

We conducted a retrospective study including patients with a BMI > 25 kg/m² undergoing kidney transplantation during 5 years. Subcutaneous adipose tissue surface (SAT), visceral adipose tissue surface (VAT), and psoas surface were measured on CT scans sections. A model predictive of post-transplantation dialysis was elaborated through a multivariable logistic regression and was compared to a model including only BMI.

RESULTS

Overall, 248 patients were included whom mean (SD) BMI and age were, respectively, 29.7 kg/m2 (3.6) and 56 years (12.7). Of them, 83 (33.5%) needed dialysis: 14 (5.7%) for primary kidney failure and 69 (27.8%) for delayed kidney function. On multivariable analysis, SAT, VAT and deceased donor were significantly associated with post-operative dialysis (respectively, OR [95%CI]:1.6 [1.1-2.6], 1.6[1.1-2.6], and 7.5 [1.6-56]). The area under the curve of this predictive model was 0.70 versus 0.64 for a BMI-based model.

CONCLUSION

High VAT and SAT were associated with post-transplantation dialysis. A predictive model based on these morphometrics could provide a better appreciation of graft recovery after transplantation among obese and overweight recipients. External validation is needed.

Obesity and bariatric surgery in kidney transplantation: A clinical review

Obesity is increasing worldwide, and this has major implications in the setting of kidney transplantation. Patients with obesity may have limited access to transplantation and increased posttransplant morbidity and mortality. Most transplant centers incorporate interventions aiming to target obesity in kidney transplant candidates, including dietary education and lifestyle modifications. For those failing nutritional restriction and medical therapy, the use of bariatric surgery may increase the transplant candidacy of patients with obesity and end-stage renal disease (ESRD) and may potentially improve the immediate and late outcomes. Bariatric surgery in ESRD patients is associated with weight loss ranging from 29.8% to 72.8% excess weight loss, with reported mortality and morbidity rates of 2% and 7%, respectively. The most commonly performed bariatric surgical procedures in patients with ESRD and in transplant patients are laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass. However, the correct timing of bariatric surgery and the ideal type of surgery have yet to be determined, although pretransplant LSG seems to be associated with an acceptable risk-benefit profile. We review the impact of obesity on kidney transplant candidates and recipients and in potential living kidney donors, exploring the potential impact of bariatric surgery in addressing obesity in these populations, thereby potentially improving posttransplant outcomes.

Obesity as an isolated contraindication to kidney transplantation in the end-stage renal disease population: A cohort study

OBJECTIVE

The aim of this study was to characterize end-stage renal disease (ESRD) patients with obesity as their only contraindication to listing and to quantify wait-list and transplant access.

METHODS

Using the US Renal Data System, a retrospective cohort study of incident dialysis cases (2012 to 2014) was performed. The primary outcomes were time to wait-listing and time to transplantation.

RESULTS

Of 157,572 dialysis patients not already listed, 39,844 had BMI as their only demonstrable transplant contraindication. They tended to be younger, female, and Black. Compared with patients with BMI < 35, those with BMI 35 to 39.9, 40 to 44.9, and ≥45 were, respectively, 15% (adjusted hazard ratio [aHR] 0.85; 95% CI: 0.83-0.88; p < 0.001), 45% (aHR 0.55; 95% CI: 0.52-0.57; p < 0.001), and 71% (aHR 0.29; 95% CI: 0.27-0.31; p < 0.001) less likely to be wait-listed. Wait-listed patients with BMI 35 to 39.9 were 24% less likely to achieve transplant (aHR 0.76; 95% CI: 0.72-0.80; p < 0.0001), BMI 40 to 44.9 were 21% less likely (aHR 0.79; 95% CI: 0.72-0.86; p < 0.0001), and BMI ≥ 45 were 15% less likely (aHR 0.85; 95% CI: 0.75-0.95; p = 0.004) compared with patients with BMI < 35.

CONCLUSIONS

Obesity was the sole contraindication to wait-listing for 40,000 dialysis patients. They were less likely to be wait-listed. For those who were, they had a lower likelihood of transplant. Aggressive weight-loss interventions may help this population achieve wait-listing and transplant.

Recipient Obesity and Kidney Transplant Outcomes: A Mate-Kidney Analysis

RATIONALE & OBJECTIVE

The impact of extreme recipient obesity on long-term kidney transplant outcomes has been controversial. This study sought to evaluate the association of various levels of recipient obesity on kidney transplantation outcomes by comparing mate-kidney recipient pairs to address possible confounding effects of donor characteristics on posttransplant outcomes.

STUDY DESIGN

Nationwide observational cohort study using mate-kidney models.

SETTING & PARTICIPANTS

In analysis based on the Organ Procurement and Transplant Network/United Network of Organ Sharing database, 44,560 adult recipients of first-time deceased-donor kidney transplants from 2001 through 2016 were paired by donor.

PREDICTORS

Recipient body mass index (BMI) categorized as 18-25 (n = 12,446), >25-30 (n = 15,477), >30-35 (n = 11,144; obese), and >35 (n = 5,493; extreme obesity) kg/m².

OUTCOMES

Outcomes included patient survival, graft survival, death-censored graft survival, delayed graft function (DGF), and hospital length of stay.

ANALYTICAL APPROACH

Conditional logistic regression and stratified proportional hazards models were used to compare outcomes as odds ratios and hazard ratios (HRs), adjusted for recipient and transplant factors, using recipients with a BMI >35 kg/m² as a reference.

RESULTS

At a median follow-up of 3.9 years, adjusted odds ratios for DGF were 0.42 (95% CI, 0.36-0.48), 0.55 (95% CI, 0.48-0.62), and 0.73 (95% CI, 0.64-0.83) for BMI 18-25, >25-30, and >30-35 kg/m², respectively (P < 0.001 for all). Death-censored graft failure was less frequent for BMI ≤25 and >25-30 kg/m² (HRs of 0.66 [95% CI, 0.59-0.74] and 0.79 [95% CI, 0.70-0.88], respectively; P < 0.001 for both), but not for BMI >30-35 kg/m² (HR, 0.91 [95% CI, 0.81-1.02]; P = 0.09). Length of stay and patient survival did not differ by recipient BMI.

LIMITATIONS

Observational study with limited detail regarding potential confounders.

CONCLUSIONS

Despite an increased risk of DGF likely unrelated to donor organ quality, long-term transplant outcomes among recipients with a BMI >35 kg/m² are similar to those among recipients with a BMI >30-35 kg/m², supporting a flexible approach to kidney transplantation candidacy in candidates with extreme obesity.

A Nephrologist Perspective on Obesity: From Kidney Injury to Clinical Management

Obesity is one of the epidemics of our era. Its prevalence is higher than 30% in the U.S. and it is estimated to increase by 50% in 2030. Obesity is associated with a higher risk of all-cause mortality and it is known to be a cause of chronic kidney disease (CKD). Typically, obesity-related glomerulopathy (ORG) is ascribed to renal hemodynamic changes that lead to hyperfiltration, albuminuria and, finally, impairment in glomerular filtration rate due to glomerulosclerosis. Though not only hemodynamics are responsible for ORG: adipokines could cause local effects on mesangial and tubular cells and podocytes promoting maladaptive responses to hyperfiltration. Furthermore, hypertension and type 2 diabetes mellitus, two conditions generally associated with obesity, are both amplifiers of obesity injury in the renal parenchyma, as well as complications of overweight. As in the native kidney, obesity is also related to worse outcomes in kidney transplantation. Despite its impact in CKD and cardiovascular morbility and mortality, therapeutic strategies to fight against obesity-related CKD were limited for decades to renin-angiotensin blockade and bariatric surgery for patients who accomplished very restrictive criteria. Last years, different drugs have been approved or are under study for the treatment of obesity. Glucagon-like peptide-1 receptor agonists are promising in obesity-related CKD since they have shown benefits in terms of losing weight in obese patients, as well as preventing the onset of macroalbuminuria and slowing the decline of eGFR in type 2 diabetes. These new families of glucose-lowering drugs are a new frontier to be crossed by nephrologists to stop obesity-related CKD progression.

Simultaneous robotic kidney transplantation and bariatric surgery for morbidly obese patients with end-stage renal failure

Patients with obesity have limited access to kidney transplantation, mainly due to an increased incidence of surgical complications, which could be reduced with selective use of robotic-assisted surgery. This prospective randomized controlled trial compares the safety and efficacy of combining robotic sleeve gastrectomy and robotic-assisted kidney transplant to robotic kidney transplant alone in candidates with class II or III obesity. Twenty candidates were recruited, 11 were randomized to the robotic sleeve gastrectomy and robotic-assisted kidney transplant group and 9 to the robotic kidney transplant group. At 12-month follow-up, change in body mass index was -8.76 ± 1.82 in the robotic sleeve gastrectomy and robotic-assisted kidney transplant group compared to 1.70 ± 2.30 in the robotic kidney transplant group (P = .0041). Estimated glomerular filtration rate, serum creatinine, readmission rates, and graft failure rates up to 12 months were not different between the two groups. Length of surgery was longer in the robotic sleeve gastrectomy and robotic-assisted kidney transplant group (405 minutes vs. 269 minutes, p = .00304) without increase in estimated blood loss (120 ml vs. 117 ml, p = .908) or incidence of surgical complications. Combined robotic-assisted kidney transplant and sleeve gastrectomy is safe and effective compared to robotic-assisted kidney transplant alone.

Initial Experience with Single-port Robotic-assisted Kidney Transplantation and Autotransplantation

BACKGROUND

Compared with the standard open approach, multiport robotic-assisted kidney transplantation (RAKT) has emerged as a less morbid alternative. The use of a single-port robotic approach for kidney transplantation (KT) is presented in this study as having the potential for further reducing the morbidity of KT.

OBJECTIVE

To present the technique and evaluate perioperative and short-term (≤1 yr) postoperative outcomes of single-port RAKT.

DESIGN, SETTING, AND PARTICIPANTS

Prospective evaluation of peri- and postoperative outcomes in patients who underwent allograft KT (n = 6) or kidney autotransplantation (n = 3). The IDEAL model (www.ideal-collaboration.net/framework) for safe surgical innovation was used.

SURGICAL PROCEDURE

Kidney allografts from living or deceased donors were transplanted into six patients with end-stage renal disease. Single-port robotic surgery was performed through a 5-cm midline periumbilical abdominal incision with transperitoneal or extraperitoneal approaches. With similar incision and technique, the right or left kidney was removed and autotransplantation was performed in three patients.

MEASUREMENTS

Intra- and postoperative variables, and outcomes were assessed with a descriptive analysis.

RESULTS AND LIMITATIONS

Single-port RAKT procedures were completed successfully, with total operative and vascular anastomosis times ranging from 300 to 450 mins and from 52 to 92 mins, respectively. All six patients had excellent graft function with serum creatinine levels at the last follow-up (2 wk to 1 yr), ranging from 1.2 to 1.5 mg/dl. Renal autotransplantation was also completed successfully with a single-port robotic approach in three patients. The total operative and vascular anastomosis times ranged from 510 to 600 mins and from 65 to 83 mins, respectively. In all three cases, serum creatinine levels remained normal after the surgery and during follow-up, and all remained symptom-free at the time of this writing (4-8 mo after their surgeries).

CONCLUSIONS

In this initial experience, single-port RAKT is feasible with potential benefits such as offering true single-site minimally invasive surgery, extraperitoneal approach, less morbidity, and comparable short-term graft functional outcomes.

PATIENT SUMMARY

We presented the initial experience with the application of single-port robotic surgery for kidney transplantation and autotransplantation. This technique was found to be safe and effective, with promising postoperative outcomes and potentially with less morbidity.

Effects of body mass index on kidney transplant outcomes are significantly modified by patient characteristics

Body mass index (BMI) is a known risk factor associated with kidney transplant outcomes and is incorporated for determining transplant candidate eligibility. However, BMI is a coarse health measure and risks associated with BMI may vary by patient characteristics. We evaluated 296 807 adult (age > 17) solitary kidney transplant recipients from the Scientific Registry of Transplant Recipients (2000-2019). We examined effects of BMI using survival models and tested interactions with recipient characteristics. Overall, BMI demonstrated a "J-Shaped" risk profile with elevated risks for overall graft loss with low BMI and obesity. However, multivariable models indicated interactions between BMI with recipient age, diagnosis, gender, and race/ethnicity. Low BMI was relatively higher risk for older recipients (>60 years), people with type I diabetes, and males and demonstrated no additional risk among younger (18-39) and Hispanic recipients. High BMI was associated with elevated risk for Caucasians and attenuated risk among African Americans and people with type II diabetes. Effects of BMI had variable risks for mortality vs graft loss by recipient characteristics in competing risks models. The association of BMI with posttransplant outcomes is highly variable among kidney transplant recipients. Results are important considerations for personalized care and risk stratification. Findings suggest that transplant contraindications should not be based on absolute BMI thresholds but modified based on patient characteristics.

Risk factors for delayed graft function and their impact on graft outcomes in live donor kidney transplantation

BACKGROUND

Delayed graft function (DGF) is a manifestation of acute kidney injury uniquely framed within the transplant process and a predictor of poor long-term graft function1. It is less common in the setting of living donor (LD) kidney transplantation. However, the detrimental impact of DGF on graft survival is more pronounced in LD2.

PURPOSE

To study the effects of DGF in the setting of LD kidney transplantation.

METHODS

We performed a retrospective analysis of LD kidney transplantations performed between 2010 and 2018 in the UNOS/OPTN database for DGF and its effect on graft survival.

RESULTS

A total of 42,736 LD recipients were identified, of whom 1115 (2.6%) developed DGF. Recipient dialysis status, male gender, diabetes, end-stage renal disease, donor age, right donor nephrectomy, panel reactive antibodies, HLA mismatch, and cold ischemia time were independent predictors of DGF. Three-year graft survival in patients with and without DGF was 89% and 95%, respectively. DGF was the greatest predictor of graft failure at three years (hazard ratio = 1.766, 95% CI: 1.514-2.059, P = 0.001) and was associated with higher rates of rejection (9% vs. 6.28%, P = 0.0003). Among patients with DGF, the graft survival rates with and without rejection were not different.

CONCLUSION

DGF is a major determinant of poor graft functional outcomes, independent of rejection.