Lymphocele formation is a frequent complication after kidney transplantation, occurring in up to 26% of recipients. It results mainly from lymphatic injury during dissection of the iliac vessels and can impair graft function by compressing the renal graft, vascular structures, or ureter. Improved intraoperative visualization of lymphatic vessels may reduce this risk. Indocyanine green (ICG) fluorescence technology enables real-time lymphatic mapping. This study evaluated the feasibility and clinical utility of ICG fluorescence-guided lymphography during kidney transplantation. In a prospective single-center study, ICG lymphography was performed in 21 consecutive living-donor kidney transplantations. Under ultrasound guidance, ICG was injected into the subcutaneous tissue of the ipsilateral femoral triangle one hour before surgery. Lymphatic structures were visualized intraoperatively using a handheld fluorescence imaging system (Spy-Phi, Stryker) at four procedural time points. Identified lymphatic vessels were preserved, and any visualized lymphatic leakage was clipped. Postoperative surveillance included weekly ultrasonography in the early postoperative phase and MRI at 6 months. ICG injection enabled clear visualization of retroperitoneal lymphatic vessels in all 21 cases. Lymphatic structures were successfully preserved during dissection. In two cases, intraoperative lymphatic leakage was detected and controlled. Postoperative ultrasound showed no perirenal fluid collections in any patient. MRI performed in 15/21 patients at 6 months confirmed absence of lymphocele formation. ICG-guided lymphography is a safe, feasible technique for intraoperative visualization of lymphatic vessels during kidney transplantation and may help prevent lymphocele formation.

Organ procurement organizations are increasingly turning to expedited (ie, out-of-sequence) allocation of deceased donor kidneys, citing maximal utility of kidneys at risk of nonuse. To identify and compare kidney pairs from the same donor from whom 1 kidney was transplanted in sequence and the other out of sequence. This retrospective cohort study used US kidney transplant registry data obtained from the Scientific Registry of Transplant Recipients to identify kidney transplant donors from whom at least 1 deceased donor kidney was transplanted out of sequence in 2020 through 2024. Incidence of unilateral out-of-sequence transplants, in which 1 kidney was placed in sequence and the other kidney from the same donor was placed out of sequence, and survival outcomes of recipients. A total of 15 602 kidneys from 8544 deceased donors (5304 [62.1%] male; mean [SD] age at organ recovery, 44.4 [15.1] years) with at least 1 kidney transplanted out of sequence were included in the analysis. Of these, 4313 donors (50.5%) had a unilateral kidney placed out of sequence. Compared with recipients of unilateral in-sequence kidneys, recipients of unilateral out-of-sequence kidneys included a greater percentage of older (median [IQR] age at transplant, 60.0 [50.0-67.0] vs 57.0 [47.0-65.0] years), Asian (472 [10.9%] vs 282 [6.5%]), White (2391 [66.1%] vs 2197 [50.9%]), and male (2850 [66.1%] vs 2453 [56.9%]) recipients, as well as those with private insurance (1255 [29.1%] vs 990 [23.0%]) and preemptive transplant (739 [17.1%] vs 438 [10.2%]) (all P < .001). Unilateral out-of-sequence kidneys accounted for 38.2% of all out-of-sequence transplants over the course of the study period. From 2020 through 2024, unilateral out-of-sequence kidneys increased from 97 instances from 15 organ procurement organizations to 1698 kidneys from all 56 organizations in the US. The first instance of an out-of-sequence refusal code (ie, the point in the waiting list at which kidneys were first placed out of the standard sequence) decreased from median (IQR) sequence number 393 (155-889) in 2020 to 28 (11-77) in 2024. The proportion of donor-related reasons for refusal decreased 10% to 15% during the study period. In adjusted Cox models, outcomes for unilateral out-of-sequence transplant were not significantly different for patient survival (hazard ratio, 0.84 [95% CI, 0.70-1.02]; P = .08) or graft survival (hazard ratio, 0.87 [95% CI, 0.70-1.08]; P = .20), compared with unilateral in-sequence transplant. Findings from this cohort study of unilateral out-of-sequence transplants highlight the importance of understanding donor and allocation factors that resulted in bypassing standard allocation and are critical to designing future iterations of the organ allocation system with improved organ use rates.

Urinary Microbiome Characteristics in Kidney Transplant Recipients and Their Clinical Implications: A Narrative Review

Background. Kidney preservation techniques, such as hypothermic machine perfusion (HMP), improve graft outcomes in deceased-donor kidney transplantation by pausing graft metabolism and ameliorated ischemia–reperfusion injury (IRI) but do not completely eliminate injury. Alkaline phosphatase (ALP) has been postulated to reduce IRI-induced kidney injury through the conversion of extracellular adenosine triphosphate into adenosine. This study aimed to evaluate whether ALP offers protection during deceased-donor kidney storage. Methods. Sixteen abattoir porcine kidneys (8 ALP and 8 with placebo) were procured after euthanization and exposed to 30 min of warm ischemia followed by 24 h of HMP or static cold storage (SCS). Reperfusion was partly simulated by 240 min of normothermic machine perfusion (NMP). Throughout NMP, we obtained functional, biochemical, and histological parameters. Results. Significantly lower urine production accompanied by lower perfusate pCO 2 and higher pH were observed in the ALP group throughout NMP. At the end of NMP, intracellular ATP reserves and oxygen consumption were significantly higher in the ALP-treated group. Metabolomics analysis with principal component analysis demonstrated significant differences between the ALP and placebo groups in glycolysis and mitochondrial metabolites, along with a significantly attenuated rise in perfusate lactate dehydrogenase levels. Conclusions. ALP supplementation during HMP was associated with lower urine production and energetic stress, with a shift toward less metabolic dysfunction and graft injury by the end of NMP. Our findings suggest an improvement in the early metabolic incompetency that characterizes delayed graft function in humans. Further research should elucidate whether these findings result in enhancement of graft functionality after transplantation.

Living donor kidney transplantation offers superior long-term outcomes compared to deceased donor transplantation. However, ensuring long-term donor safety remains the primary objective of the clinical assessment process. Pre-donation risk evaluation can be challenging, particularly in specific borderline scenarios where evidence is limited. This review explores several critical aspects of the decision-making process in LKD assessment. It addresses how to evaluate potential donors with complex medical or psychosocial profiles, including those with obesity, advanced age, psychiatric histories, or past substance use. The review also emphasizes the importance of using accurate and reliable tools for donor evaluation, such as measured glomerular filtration rate (mGFR), particularly in cases with borderline kidney function, and discusses the growing role of genetic testing as it becomes more accessible. Furthermore, it considers how socioeconomic, cultural, and religious factors can influence both the willingness to donate and the likelihood of being selected as a donor. Lastly, the review underscores the essential role of long-term follow-up in safeguarding donor health and optimizing outcomes. To safely expand the pool of eligible living kidney donors, it is essential to use precise evaluation tools, ensure and enable long-term follow-up, and promote research to improve risk stratification and guide decision-making. In this review, we update information in the evaluation of living kidney donors highlighting gaps in current knowledge and practice.

Left atrial (LA) volume and strain parameters have been associated with cardiovascular outcomes in several cardiac pathologies, yet their role in predicting major adverse cardiovascular events (MACE) in kidney transplant (KT) recipients has not been explored. We retrospectively reviewed the records of adult KT recipients from our institution (2015-2024). We utilized baseline echocardiograms routinely acquired during KT workup to measure LA volumetrics and strain. MACE was the study's primary endpoint, defined as cardiovascular death, nonfatal myocardial infarction, stroke, major arrhythmias or heart failure hospitalization. Logistic regression, Kaplan-Meier and Cox proportional hazards regression were performed to evaluate the association between LA parameters and MACE. Of 518 patients who underwent kidney transplant, 377 were in sinus rhythm with an acceptable quality echocardiogram (male, 56.7%; mean age 53.7 ± 13.1 years). Over a median follow up duration of 5.3 ± 2.3 years from KT, 82 patients reached the study endpoint. Kaplan-Meier analysis showed significantly lower MACE-free survival in patients with abnormal LA strain. After adjusting for confounding variables in the Cox Proportional Hazards model, of all LA parameters, lower LAScd (HR 0.94, 95% CI 0.89-0.98, p = 0.003), and LASr (HR 0.97, 95% CI 0.94-0.995, p = 0.02) were independently associated with MACE. In this retrospective single center study, LA strain parameters particularly LASr and LAScd were independently associated with MACE after KT. LA strain might have a role in risk stratification in this population.

Takayasu arteritis (TAK) is a granulomatous large-vessel vasculitis typically affecting young adult females. Pediatric cases are rare, and infantile onset is exceptional. Management relies on immunosuppression, with surgery reserved for severe complications. We describe a now 5.5-year-old boy diagnosed with TAK at six months of age, presenting with hypertensive encephalopathy and kidney dysfunction. Despite treatment with corticosteroids and anti-TNFα, his kidney function deteriorated, leading to kidney failure and dialysis. At nearly three years of age, he underwent abdominal aorto-aortic bypass and bilateral nephrectomy due to progressive vascular narrowing and refractory hypertension. At age four, he successfully received a deceased-donor kidney transplant. Eighteen months post-transplant, he maintains excellent graft function and shows no signs of TAK recurrence. This case underscores the complexity of diagnosing and managing infantile TAK with multiorgan involvement. To our knowledge, he is among the youngest reported TAK patients to undergo successful kidney transplantation following major vascular surgery. His course demonstrates the potential for long-term remission and safe transplantation under standard immunosuppression, without continued anti-TNFα therapy. The literature is sparse regarding kidney failure and transplantation in TAK, particularly in infants. This case highlights key management dilemmas in infantile TAK, including clinical diagnosis, timing of surgery and transplantation, choice of immunosuppression, and long-term monitoring. It emphasizes the importance of a multidisciplinary approach and the need for collaborative research to address knowledge gaps in this rare but complex condition.

Logical versus absolute lymphocyte count-guided preemptive therapy for cytomegalovirus prevention in kidney transplant recipients: a randomized controlled trial.

The potential of prehabilitation to enhance recovery in sarcopenic and frail older kidney transplant candidates: A narrative review.

Impaired kidney function in the non-transplant chronic kidney disease (CKD) population has been shown to negatively affect patients' health related quality of life (HRQOL). The relationship between posttransplant graft function, as measured by estimated glomerular filtration rate (eGFR), and patient-reported outcomes (PRO) remains poorly understood. This study evaluates the associations between eGFR and PRO in kidney transplant recipients to inform clinical strategies aimed at optimizing both physical and psychological well-being. Longitudinal data were collected using previously-described procedures and a multi-survey PRO battery. Logistic regression models evaluated relationships, at the last follow-up point, between eGFR strata, time posttransplant, age at PRO, whether there had been a previous kidney transplant or the donor was deceased or living, and the likelihood of physical or mental HRQOL being substantive low and of symptoms of depression or anxiety being reported. Parallel multivariable mixed effects models, that included all longitudinal data points for each participant, examined relationships between eGFR and continuous PRO scores and their temporal trajectories. The study included 2116 adult kidney transplant recipients and over 9500 unique multi-survey observation points over a 19-year period. After adjusting for age (p < 0.001), donor type, time posttransplant, and prior kidney transplantation, there was a statistically significant association between eGFR/CKD strata and the likelihood of physical HRQOL being substantively low (p < 0.001) at the last PRO assessment. CKD stage 4 or 5 was independently associated with a 1.5 times increased likelihood of reporting symptoms of depression (OR: 1.50; 95% CI 1.16, 1.95) and anxiety (OR = 1.48; 95%CI: 1.14, 1.92) compared to those with eGFR ≥ 60mL/min/1.73m2. Longitudinal analyses comprising all data points demonstrated that increased eGFR was associated with better physical and mental HRQOL and reduced symptoms of depression and anxiety. Impaired graft function is significantly associated with decreased physical HRQOL and increased symptoms of depression and anxiety in kidney transplant recipients. These findings underscore the importance of close monitoring and early interventions targeting physical and psychological well-being as graft function declines.

Patients presenting for kidney transplantation on antithrombotic therapy may face an increased risk of bleeding and surgery-related morbidity. How to best optimize pre-operative antithrombotic therapies to decrease the risk for allograft complications has not been fully elucidated. This was a single-center, retrospective study of adult patients undergoing kidney transplantation between 2018-2024. Patients taking oral anticoagulants or antiplatelet therapies at the time of organ offer were compared to control patients not on antithrombotics. A subgroup analysis was also performed, comparing patients on warfarin versus apixaban. The primary endpoint was combined patient and allograft survival at 6 months post-transplant. Key secondary endpoints included the incidence of delayed allograft function, blood product requirements and re-operation, and estimated glomerular filtration rate. 27 patients on anticoagulants and 26 patients on antiplatelet therapies were compared to 227 controls. No significant differences were observed in allograft survival between anticoagulant (96.3%), antiplatelet (88.5%), and control (93.4%) groups. Patients on anticoagulants exhibited a higher incidence of bleeding complications including increased blood product requirements (2.0 vs. 0.6; p < 0.01) and re-operation (14.8% vs. 4.4%; p = 0.04) relative to controls, although this did not impact allograft function. No differences were observed in survival or bleeding endpoints between patients on warfarin and apixaban. Use of anticoagulant but not antiplatelet therapy prior to transplantation was associated with an increased risk of bleeding complications, without adversely affecting short-term allograft function. These results suggest that anticoagulant and antiplatelet therapies may be continued until the time of organ offer in select patients, and apixaban may be a suitable alternative to warfarin for patients on the transplant waiting list.

Acute kidney injury (AKI) in pregnancy among women with kidney transplants is rarely addressed in the literature. There is no consensus definition of AKI among this population, and limited data exist on the different aetiologies and outcomes, thereby creating a significant knowledge gap. Pregnancy among patients with a kidney transplant is considered high risk due to the possibility of foetal and maternal risks, AKI and graft loss during pregnancy. This is a case series report of two post-kidney transplant patients who developed multiple episodes of AKI in the course of pregnancy. There was no identifiable pre-renal, intrinsic renal, post-renal or transplant-specific cause for the AKI. There was a failure of the first-trimester dip in serum creatinine in both patients. In addition, the serum creatinine stabilised between 6 and 12 months post-delivery, albeit at a higher level. The renal biopsy done was negative for rejection or polyoma virus nephropathy. Failure of the first trimester dip in serum creatinine may be a risk factor for AKI in pregnant transplant patient which may in turn have deleterious short term and long term outcomes on kidney function.

A0239 Dynamic donor-derived cfDNA normalization after kidney transplantation: Preliminary results from a personalized NGS and AI-based monitoring platform

Disseminated histoplasmosis is a potentially serious complication after organ transplantation; however, its occurrence is rare, even in endemic regions. Diagnosis can be challenging, particularly in patients with nonspecific symptoms such as intermittent fever or lethargy. We report the case of a man who presented with intermittent fever 10 years after kidney transplantation. His presentation initially raised suspicion for post-transplant lymphoproliferative disorder (PTLD) but was ultimately diagnosed as disseminated histoplasmosis following mediastinal lymph node biopsy and fungal tissue culture.

P0312 Viral infections and tumour-specific mortality after kidney transplantation: Distinct CMV and EBV patterns across tumour types and stages

A0238 XBP1s-GAS1 mediates the formation of tertiary lymphoid structures after kidney transplantation in elderly donors through the Hedgehog signaling pathway

Highly Repeatable Tissue Proteomics for Kidney Transplant Pathology: Technical and Biological Validation of Protein Analysis Using Liquid Chromatography-Tandem Mass Spectrometry/Mass Spectrometry (LC-MS/MS).

The increase in chronic kidney disease prevalence and its risk factors have pressured universal health systems to expand the supply of kidney replacement therapy (KRT - hemodialysis, peritoneal dialysis and kidney transplantation). Particularly in low- and middle-income countries and those undergoing a fast epidemiological and demographic transition, the access to nephrology consultations and multidisciplinary care is limited, and the majority of patients start KRT in an unplanned manner or during emergency hospitalization. Even patients with adequate pre-dialysis care and elective requests for KRT are at risk of clinical decompensation and requiring hospitalization to start emergency dialysis; this risk increases the longer the delay in starting KRT. In both cases, the patient's access to an outpatient dialysis unit must be timely and the transition of care safe. There are Brazilian and international guidelines for patients who are prevalent on dialysis. However, there are no clear recommendations for regulating access to the start of outpatient KRT, which often leads to divergent opinions among healthcare professionals and contributes to the inefficiency of the regulatory process. This document aims to: (1) list the main challenges in the daily practice of the regulatory professionals in the Brazilian Unified Health System; (2) present recommendations from the Brazilian Society of Nephrology based on scientific evidence and available legislation.

P0067 Urethroplasty after kidney transplantation: A reconstructive challenge in a high risk population

The increase in chronic kidney disease prevalence and its risk factors havepressured universal health systems to expand the supply of kidney replacementtherapy (KRT - hemodialysis, peritoneal dialysis and kidney transplantation).Particularly in low- and middle-income countries and those undergoing a fastepidemiological and demographic transition, the access to nephrologyconsultations and multidisciplinary care is limited, and the majority ofpatients start KRT in an unplanned manner or during emergency hospitalization.Even patients with adequate pre-dialysis care and elective requests for KRT areat risk of clinical decompensation and requiring hospitalization to startemergency dialysis; this risk increases the longer the delay in starting KRT. Inboth cases, the patient’s access to an outpatient dialysis unit must be timelyand the transition of care safe. There are Brazilian and internationalguidelines for patients who are prevalent on dialysis. However, there are noclear recommendations for regulating access to the start of outpatient KRT,which often leads to divergent opinions among healthcare professionals andcontributes to the inefficiency of the regulatory process. This document aimsto: (1) list the main challenges in the daily practice of the regulatoryprofessionals in the Brazilian Unified Health System; (2) presentrecommendations from the Brazilian Society of Nephrology based on scientificevidence and available legislation.