A novel approach to therapeutic drug monitoring of Ciclosporin in pediatric renal transplant recipients using volumetric absorptive microsampling (VAMS) - Teaching old dog new tricks.

BACKGROUND AND AIMS: Ciclosporin (CSA) is an immunosuppressive agent that requires therapeutic drug monitoring (TDM). High partitioning in erythrocytes indicates that whole blood (WB) is a suitable matrix for CSA determination. Alternative sampling strategies, such as volumetric absorptive microsampling (VAMS), are novel possibilities for blood collection during TDM for various analytes, including immunosuppressants. This technique is attractive for vulnerable pediatric patients, including home-based self-sampling, remote therapy, and adherence control. MATERIALS AND METHODS: This study aimed to develop and validate a new method for CSA determination based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) of WB and VAMS samples. Additionally, these methods were applied for CSA determination in clinical samples from pediatric transplant recipients. A strong point of this study is the assessment of an external proficiency testing scheme. RESULTS: Both methods were successfully validated within the 1 - 2000 ng/mL calibration range, with LOD 0.5 and 1 ng/mL for WB and VAMS methods, respectively. All the validation parameters fulfilled the international acceptance criteria for bioanalytical methods. Cross-validation confirmed the interchangeability of the LC-MS/MS method developed in this study. CONCLUSION: This study developed and validated novel methods for CSA determination in whole blood and VAMS using LC-MS/MS. Clinical validation and proficiency testing confirmed their utility in routine clinical practice.

Rectus sheath patch. A novel surgical technique in the repair of isolated renal pelvis necrosis in a transplanted kidney. A case report.

INTRODUCTION: Focal necrosis of the renal pelvis in a transplanted kidney is a rare but often morbid complication that may lead to graft loss. Given the scarcity of donor organs, all attempts are made to preserve the graft. Currently there is no standard surgical technique for reconstruction or repair of isolated renal pelvic necrosis. PRESENTATION OF CASE: A 70-year-old male with end stage kidney disease underwent renal transplantation. The patient developed a day-three post-operative urine leak. During surgical exploration, a focal area of pelvic necrosis was observed without evidence of proximal or distal ureteric involvement. Given the excellent function of the renal allograft, a novel surgical technique was successfully used to repair the necrotic defect. Reconstruction of the renal pelvis was performed using an avascular rectus sheath patch. The patch was secured over the open pelvis following necrotic tissue debridement. The patient made a successful recovery with complete resolution of urine leak. A 6-week post-operative retrograde pyelogram confirmed no ongoing urine leak. DISCUSSION: To restore anatomy, the pelvic defect was patched with avascular rectus sheath fascia. Advantages of this reconstructive method were technique simplicity and low donor site morbidity. Potential complications included patch failure with ongoing urine leak, ventral wall hernia through the fascial donor site and stenosis of the ureteropelvic junction. CONCLUSION: This case highlights the successful surgical management of a renal pelvis urine leak patched with rectus sheath fascia. This technique could be considered as a graft saving procedure in similar cases where the alternative is transplant nephrectomy.

Cancer Screening in Renal Transplant Recipients: Real-World Data.

Background: Multiple international guidelines have endorsed cancer screening in renal transplant patients. This study aimed to describe a series of patients with post-transplant cancer and to report physicians' adherence to cancer screening guidelines. Methods: This is a retrospective study of cancer patients who had a history of renal transplant. Charts of patients who were treated at our institution between 2012 and 2023 were reviewed, patients' clinical data were collected. Results: Thirty-nine patients were identified. The most common types of cancer were lymphoma (n = 9, 23%), squamous cell carcinoma (SCC) of the skin (n = 8, 20.5%), and breast (n = 6, 15.4%). The median age at diagnosis was 56.5 years (range: 16.9 - 70.2), family history of malignancy was depicted in 18 (46.2%) cases. Chart review and patients' questionnaire revealed that increased risk of malignancy was discussed in seven (18%) out of 39 recipients (P < 0.001) at time of transplant, and only three (7.7%, P < 0.001) patients were on post-transplant age-matched cancer screening. Conclusions: The increased risk of malignancy is a serious post-transplant complication. Lymphoma and non-melanoma skin cancer were the most common cancers. Most patients were not offered routine cancer screening; it is important to raise awareness among nephrologists and caregivers regarding the risk of post-transplant malignancy.

Definitive chemoradiotherapy for a patient with anal cancer after renal transplantation.

Patients after renal transplantation are susceptible to secondary malignancies, including anal squamous cell carcinoma. Chemoradiotherapy is the standard treatment for anal squamous cell carcinoma; however, typical irradiation fields for anal cancer encompass a transplanted kidney located in the right iliac fossa, which causes complete renal dysfunction. Thus, typical irradiation fields are not feasible for this population. Additionally, standard concurrent chemotherapy demonstrates nephrotoxicity. Here, we report a case of modified definitive chemoradiotherapy for a 40-year-old patient with locally advanced perianal squamous cell carcinoma after renal transplantation whose abdominoperineal resection was difficult because of a history of repeated open surgeries and long-term steroids. We modified the cranial side of the elective nodal irradiation fields in this case to spare the transplanted kidney, considering the lymph chains of the perianal tumor. We then used continuous 5-fluorouracil to avoid nephrotoxicity of mitomycin C, considering his life expectancy. Modified definitive chemoradiotherapy achieved complete remission with expected toxicities. Now, approximately five years after the procedure, the patient remains disease-free, preserving anal and renal function. Definitive chemoradiotherapy using modified irradiation fields and chemotherapy may be an option for patients with anal squamous cell carcinoma after renal transplantation.

Redo Tricuspid and Pulmonary Valve Replacement with On-X in Renal Transplant Patient: A Case Report.

Surgical treatment is recommended in patients with symptomatic severe tricuspid regurgitation and pulmonary regurgitation. Although renal transplant patients are a high-risk patient group for cardiac surgery, heart valve surgeries can be performed successfully. There are a limited number of studies published on this subject in the literature. Therefore, we present a case who underwent tricuspid ring annuloplasty (TRA) before being followed up with renal transplantation and then successfully performed redo tricuspid valve replacement (TVR) and pulmonary valve replacement (PVR).

Immune checkpoint inhibitors and renal toxicity.

Immune checkpoint inhibitors (ICIs) have transformed the management of a broad spectrum of cancers as metastatic melanoma, non-small lung cancer or renal cell carcinoma. These humanized monoclonal antibodies target immune-regulatory receptors expressed on T lymphocytes, antigen presenting cells and tumor cells and induce an immunological anti-tumor response. If on the one hand these molecules have led to considerable improvement in survival outcomes, on the other hand these therapies can be associated with immune-related adverse effects (irAEs). While these side effects have become well known, the best diagnostic and therapeutic approaches are still under investigation. The authors discuss pathophysiology, clinical presentation and histological features of ICIs renal toxicity. Furthermore, we focus on kidney transplant (KT) recipients, including the therapeutic adaptation approach to immunosuppression and the risk of rejection.

Total Hip Arthroplasty Outcomes before or after Renal Transplant: A Retrospective Large Cohort Analysis.

Background: While it is known that patients with end-stage renal disease (ESRD) are at an increased risk of complications following total hip arthroplasty (THA), there is a gap in the literature in comparing patients with ESRD to patients who undergo renal transplant (RT) before or after THA. This study is to address this gap by analyzing outcomes of THA in ESRD patients, RT patients, and RT candidates. Methods: Using the PearlDiver Mariner database, ESRD patients, RT patients, and RT candidates undergoing primary THA were identified and compared. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to 2 years. Ninety-day emergency department (ED) visits and inpatient readmission were also documented. Results: A total of 7,868 patients were included: 5,092 had ESRD, 2,520 had RT before THA, and 256 were candidates for RT. Compared to patients with ESRD, RT patients demonstrated lower rates of medical complications such as pneumonia (3.61% vs. 5.99%, p = 0.039) and transfusion (4.60% vs. 7.66%, p < 0.001). Additionally, RT patients displayed decreased rates of surgical complications, including wound complications (2.70% vs. 4.22%, p = 0.001), periprosthetic joint infection (PJI) at 1 year (2.30% vs. 4.81%, p < 0.001) and 2 years (2.58% vs. 5.42%, p < 0.001), and aseptic loosening at 2 years (0.79% vs. 1.43%, p = 0.006). Similarly, when compared to RT candidates, RT patients demonstrated a lower incidence of postoperative complications, including 1-year PJI (2.30% vs. 5.08%, p = 0.013), 2-year PJI (2.58% vs. 5.08%, p = 0.028), 1-year aseptic loosening (0.56% vs. 2.73%, p < 0.001), and 2-year aseptic loosening (0.79% vs. 2.73%, p = 0.005). RT patients also had lower rates of ED visits and hospital readmissions. Conclusions: Compared to ESRD patients and RT candidates, patients with RT have a significantly lower likelihood of medical complications, PJI, aseptic hardware loosening, ED visits, and hospital readmission. Patients with ESRD on the RT waiting list should delay THA until after RT surgery. For those not eligible for RT, it is vital to take extra precautions to reduce the risk of complications.

Metastatic pulmonary calcification in a renal transplant recipient.

Metastatic pulmonary calcification (MPC) is a metabolic disorder characterized by an ectopic deposition of calcium in the lung parenchyma, prevalent in patients with chronic kidney disease. A combination of parenchymal lung abnormalities on high resolution chest computed tomography (CT) and pulmonary radiotracer uptake in 99mTc-methyl diphosphate (MDP) bone scintigraphy can establish diagnosis of MPC. We herein present a case of MPC with documented stability of chest CT abnormalities after renal transplant. We also describe novel findings of diffuse pulmonary uptake of 18F-sodium fluoride, a calcium-avid radiotracer, in positron emission tomography (PET)/CT performed in the same patient.

Percutaneous nephrolithotomy for adult renal transplant de novo graft lithiasis: a single center analysis and systematic review of the literature.

INTRODUCTION/OBJECTIVE: Graft stones in renal transplant recipients pose a unique challenge, finding effective interventions to ensure optimal graft function and patient well-being. Various methods of stone clearance have been described for graft stones, including percutaneous nephrolithotomy (PCNL). While PCNL is a promising approach for managing graft stones, specific outcomes and associated characteristics for this approach have not been comprehensively evaluated before. This study aims to evaluate the safety and efficacy of the use of PCNL as the primary intervention of graft stones by assessing stone-free rates (SFR), treatment impact on graft function, and perioperative complications. METHODS: A retrospective clinical audit was performed for all transplants performed in a single center from 2007 to 2022, which included all graft lithiasis patients who were treated with PCNL. Both perioperative parameters and post-operative outcomes were collected. In addition, a systematic review including articles from MEDLINE, Embase, Web of Science yielded 18 full-text articles published between 1/1/2000 and 15/11/2023. The results pertaining to patients who underwent PCNLs for graft stones were cross-referenced and thoroughly evaluated. The review encompassed a comprehensive analysis of clinical data, postoperative outcomes, and procedural details. The protocol for the systematic review was prospectively registered on PROSPERO (CRD42023486825). RESULTS: In our center, 6 graft lithiasis patients were treated with PCNL. The initial SFR was 83.3%. SFR at 3 months and 1 year were both 100.0%. SFR at 3 years was 66.7%. Other centers reported initial SFR of 82.6-100.0% (interquartile range). SFR at 3 months, 1 year, 3 years was not well reported across the included studies. Incidence of graft lithiasis ranged from 0.44%-2.41%. Most common presentations at diagnosis were oliguria/anuria/acute kidney injury and asymptomatic. Reported complications included blood loss, transient hematuria, high urine output, sepsis, and damage to surrounding structures. The most commonly reported metabolic abnormalities in transplant lithiasis patients included hyperuricemia and hyperparathyroidism. CONCLUSION: PCNL is a practical and efficient choice for addressing graft lithiasis, demonstrating excellent stone clearance and minimal perioperative complications. These findings show the importance of PCNL as a primary intervention in this complex patient population.

Assessment of the herpes zoster risk among renal transplant recipients administered the influenza vaccine.

BACKGROUND: Reactivation of the latent varicella-zoster virus can cause herpes zoster (HZ) infection, and renal transplant recipients undergoing immunosuppressive therapy are particularly susceptible to this condition. This study aims to evaluate the potential increase in HZ incidence following influenza vaccination among this specific patient population. METHODS: This study was a population-based, retrospective, self-controlled case series. Data were retrieved from Taiwan's National Health Insurance Research Database spanning the years 2008 to 2017. Patients diagnosed with HZ within a 6-month period before and after receiving the influenza vaccine were eligible for inclusion. Two distinct time intervals were defined for analysis: the initial 15 days and 30 days following vaccination were categorized as risk intervals, while all other periods served as control intervals. Incidence rate ratios (IRRs) were computed to compare HZ incidence during the risk intervals with that during the control intervals. RESULTS: This study encompassed a cohort of 4,222 renal transplant recipients who had received the influenza vaccine. Among this group, 67 recipients were subsequently diagnosed with HZ. The IRR during both the initial 15 days (IRR = 0.63; 95 % CI, 0.23-1.89) and the first 30 days (IRR = 1.50; 95 % CI, 0.71-3.16) following influenza vaccination did not demonstrate a statistically significant increase when compared to the post-exposure observation times. Comparable results were also observed when comparing these IRR values to the pre-exposure observation times. The subgroup analysis, stratified by age, sex, and underlying medical conditions (including cancer and autoimmune diseases), revealed that the IRRs did not exhibit statistically significant differences. CONCLUSIONS: No significant association between the influenza vaccine and an elevated risk of HZ was detected. The administration of annual influenza vaccines appears to be a reasonable practice for renal transplant recipients.

Contrast-enhanced ultrasound of renal masses in the pre-transplant setting: literature review with case highlights.

With the rising incidence of chronic kidney disease worldwide, an increasing number of patients are expected to require renal transplantation, which remains the definitive treatment of end stage renal disease. Medical imaging, primarily ultrasonography and contrast-enhanced CT and/or MRI, plays a large role in pre-transplantation assessment, especially in the characterization of lesions within the native kidneys. However, patients with CKD/ESRD often have relative contraindications to CT- and MR-contrast agents, limiting their utilization within this patient population. Contrast-enhanced ultrasound (CEUS), which combines the high temporal and spatial resolution of ultrasonography with intravascular microbubble contrast agents, provides a promising alternative. This review aims to familiarize the reader with the literature regarding the use of CEUS in the evaluation of cystic and solid renal lesions and provide case examples of its use at our institution in the pre-transplant setting.

Improving prediction of tacrolimus concentration using a combination of population pharmacokinetic modeling and machine learning in chinese renal transplant recipients.

Aims: The population pharmacokinetic (PPK) model-based machine learning (ML) approach offers a novel perspective on individual concentration prediction. This study aimed to establish a PPK-based ML model for predicting tacrolimus (TAC) concentrations in Chinese renal transplant recipients. Methods: Conventional TAC monitoring data from 127 Chinese renal transplant patients were divided into training (80%) and testing (20%) datasets. A PPK model was developed using the training group data. ML models were then established based on individual pharmacokinetic data derived from the PPK basic model. The prediction performances of the PPK-based ML model and Bayesian forecasting approach were compared using data from the test group. Results: The final PPK model, incorporating hematocrit and CYP3A5 genotypes as covariates, was successfully established. Individual predictions of TAC using the PPK basic model, postoperative date, CYP3A5 genotype, and hematocrit showed improved rankings in ML model construction. XGBoost, based on the TAC PPK, exhibited the best prediction performance. Conclusion: The PPK-based machine learning approach emerges as a superior option for predicting TAC concentrations in Chinese renal transplant recipients.

Late pregnancy in women with renal transplants: A multidisciplinary guide.

Kidney transplant recipients are at risk of complications in late pregnancy, with increased rates of pre-eclampsia, intrauterine growth restriction and preterm birth. It is recommended that these women receive more intensive monitoring after 20 weeks' gestation, ideally provided by a multidisciplinary team in a tertiary centre. This review focuses on the management of late pregnancy in kidney transplant recipients, from the perspective of different members of the multidisciplinary team. This includes evidence and guidance to inform the nephrologist, obstetrician, obstetric anaesthetist, transplant surgeon, midwife, and a summary of the woman's perspective. The review outlines a late pregnancy and early postnatal care pathway as a common algorithm to be used by the whole multidisciplinary team.

Diagnosing and Managing Urinary Tract Infections in Kidney Transplant Recipients.

In the article, the authors review antibiotic treatment options for both acute uncomplicated UTI and complicated UTI. In addition, they review alternative regimens which are needed in the setting of drug-resistant pathogens including vancomycin-resistant Enterococcus, -extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E), carbapenem-resistant Enterobacterales, and carbapenem-resistant Pseudomonas, which are encountered with more frequency.

Prevalence of Musculoskeletal and Metabolic Disorders in Kidney Transplant Recipients: A Systematic Review and Meta-Analysis.

Introduction: Musculoskeletal disorders could be associated with metabolic disorders that are common after kidney transplantation, which could reduce the quality of life of patients. The aim of this study was to assess the prevalence of both musculoskeletal and metabolic disorders in kidney transplant patients. Methods: MEDLINE, CINAHL, Cochrane Library, EMBASE and Web of Science were searched from their inception up to June 2023. DerSimonian and Laird random-effects method was used to calculate pooled prevalence estimates and their 95% confidence intervals (CIs). Results: 21,879 kidney transplant recipients from 38 studies were analysed. The overall proportion of kidney transplant patients with musculoskeletal disorders was 27.2% (95% CI: 18.4-36.0), with low muscle strength (64.5%; 95% CI: 43.1-81.3) being the most common disorder. Otherwise, the overall proportion of kidney transplant patients with metabolic disorders was 37.6% (95% CI: 21.9-53.2), with hypovitaminosis D (81.8%; 95% CI: 67.2-90.8) being the most prevalent disorder. Conclusion: The most common musculoskeletal disorders were low muscle strength, femoral osteopenia, and low muscle mass. Hypovitaminosis D, hyperparathyroidism, and hyperuricemia were also the most common metabolic disorders. These disorders could be associated with poorer quality of life in kidney transplant recipients. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier [CRD42023449171].

Robotic-Assisted Management of Ureteral Complications in Post-Renal Transplant Patients: A Case Series and Literature Review.

Introduction: Urologic complications are thought to be the most common surgical complication of renal transplantation. Ureteral pathology, including stenosis, urine leak, and vesicoureteral reflux, predominates. Although endourologic and interventional radiological management may be utilized, failure rates remain relatively high and surgical reconstruction remains the definitive management. Robotic ureteral reconstruction has been demonstrated to provide patient benefit in nontransplant populations, but the literature on transplant reconstruction is very limited. This study reports an additional series of patients with a focus on surgical technique, as well as reviews the available evidence for robotic reconstruction for post-transplant ureteral complications. Methods: All institutional patients undergoing robotic-assisted reconstruction for post-transplant ureteral complications for the years 2019-2022 were included. Intra- and postoperative variables, patient demographics, and follow-up data were obtained retrospectively from parsing of patient records. Statistics were tabulated descriptively. Results: Eleven patients underwent ureteral reconstruction. Of the 11, 9 (81%) were male with a mean age of 51.9 years (16-70) and BMI of 33.8 (24.3-49.1). The most common (10/11) indication for reconstruction was stricture; the most common (10/11) technique used was Lich-Gregoir reimplantation. Mean operative time was 288 minutes (143-500). There were no intra- or immediate postoperative complications. Median length of stay was 2 days (1-22). There were two incidences of mortality at 2 and 5 months postoperatively unrelated to surgery. There were four readmissions within 30 days, three for urinary tract infection (UTI) and one for a pelvic abscess which required washout. The remainder of the cohort has been followed for a mean of 14.6 months (6-41) without any incidences of graft loss or recurrence of ureteral pathology. Conclusions: Robotic-assisted ureteral reconstruction is a technically challenging but highly feasible technique that may provide the benefits of minimally invasive surgery while still allowing definitive reconstruction. Centers with extensive robotic capabilities should consider the technique.

Lateral sacral artery aneurysm.

A rare case of aneurysm of the lateral sacral artery is reported. This 46-year-old female presented with complaints of bowel and bladder incontinence and decreased perianal sensation for the past 15 months. She underwent laminectomy and diskectomy for the diagnosis of a prolapsed disk at peripheral hospital where the surgeon was confronted with a severe and unexpected hemorrhage, and surgery was aborted without effective treatment. Prior medical history includes hypertensive kidney disease with a renal transplant eight years ago. Magnetic resonance imaging and angiographic findings were suggestive of a lateral sacral artery aneurysm. Patient with a history of renal transplant and presenting with cauda equina require a more thorough assessment, and a differential of lateral sacral artery aneurysm should always be kept in mind. Our purpose is to report the pre-operative features of the lateral sacral artery aneurysm and its treatment modalities.

Trichosporon asahii co-infection with Pneumocystis jiroveci in a renal transplant patient.

Trichosporon asahii is considered an opportunistic pathogen, capable of causing superficial infections in humans and invasive deep-seated infections in immunocompromised hosts. Pneumocystis jirovecii can cause life-threatening pneumonia in immunosuppressed patients. Both Trichosporon and Pneumocystis jirovecii are highly lethal in immunocompromised individuals. Here we present a case of invasive Trichosporon asahii co-infection with Pneumocystis jiroveci in a renal transplant patient.

Assessment of Tumor Markers in Renal Transplant Recipients.

Background/Aim: Malignant tumors are diagnosed using various methods, including diagnostic imaging methods. The measurement of tumor markers is commonly used because of its noninvasiveness and convenience. Furthermore, it is known that the excretion and metabolism of some tumor markers are affected by impaired renal function. In the present study, we investigated the effect of improved renal function on pre-and post-transplantation changes in tumor marker levels [carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), carbohydrate antigen 19-9 (CA19-9), and prostate-specific antigen (PSA)] in renal transplant recipients. Patients and Methods: A total of 116 renal transplant recipients, who had not been diagnosed with malignancies between January 2012 and December 2019, were included, and tumor markers were investigated. Results: CEA showed a significant decrease after kidney transplantation, regardless of the dialysis type (3.6→2.6 ng/ml, p<0.001), while other tumor markers showed a significant increase (AFP: 3.6→3.7 ng/ml; CA19-9: 16.2→19.5 U/ml; PSA: 0.95→1.05 ng/ml; all p<0.05). Pre- and postoperative eGFR ratios and postoperative liver function were identified as factors influencing the postoperative CEA and CA19-9 values, while PSA was influenced by the duration of dialysis. No statistically significant factors were found for AFP levels. Conclusion: Caution should be exercised when investigating tumor markers in patients with renal dysfunction, as tumor marker levels may vary depending on the pathophysiology of each patient.