Post-transplant Renal Function Research Articles

#2287 Impact of renal reserve before donation in post-transplant renal function of donors and recipients

Abstract Background and Aims The influence of Renal Reserve (RR), i.e. its presence or absence, in post-transplant renal function both in living kidney donors and recipients is unknown. The presence of RR in donors may be beneficial in terms of better renal function both for the donor and recipient after transplantation. In the other hand, the absence of RR in donors might indicate a lower renal endowment and so predispose to lower GFR post-transplantation in donors and recipients. However, little evidence is available in this field. Method In a previous study (ERA Abstract 2023, #3737) we described in a group of 52 potential living kidney donors, the presence (24-46%), absence (13-25%) or use (15-29%) of RR before donation. The latter was defined as the lack of increase in GFR after stimulation in patients with basal GFR > 100 mL/min. GFR was measured before and after transplantation by the clearance of iohexol with dried blood spots. Presence of RR was defined as an increase >10% of basal GFR after IV amino acid infusion. GFR was unadjusted to body surface area (BSA). In this follow-up study we investigated the impact of the presence, absence or use of RR before donation in GFR 12 months after transplantation, both in donors and recipients. Results Of the 52 pairs of donors and recipients, renal transplantation was performed in 21 who also had 12 months of follow-up. Before transplantation 9 donors had RR, 4 did not and 8 had RR in use. Pre-transplant GFR was 95 ± 15 ml/min, 89 ± 6 ml/min and 127 ± 16 ml/min in donors with RR, without RR and with RR in use, respectively. At 12 months after kidney donation, GFR was higher in donors who had RR in use before donation: 79 ± 12 ml/min, compared with those with RR: 65 ± 9 ml/min (p = 0.048) and those without RR 59 ± 10 (p = 0.03). In recipients, GFR was comparable between those who had a donor with RR or RR in use: 72 ± 19 ml/min vs 68 ± 12 ml/min (p = ns), whereas both groups had higher GFR than those recipients whose donors had no RR before donation 53 ± 5 ml/min, although of borderline signification (p = 0.07). Non parametric tests were used. No major complications after transplantations such as rejections or surgical complications, etc, that could alter GFR were observed. Conclusion The presence or use of RR may determine a better renal function 12 months after donation both for donors and recipients. This is a preliminary study and we acknowledge that the low number of cases is a limitation and so, these results require further studies.

Association between body mass index and early renal function after kidney transplantation: observational and Mendelian randomization study.

Introduction The relationship between BMI and early renal function recovery after kidney transplantation is important due to the rising global obesity rates. Methods A retrospective study on 320 patients who received allograft kidney transplantation at Guangxi Medical University Hospital explored the BMI-kidney function relationship using various statistical methods. Mendelian randomization（MR） was also employed to investigate causality. Results Based on the univariate analysis, multivariate linear regression models, and trend analysis, it was found that there were significant positive correlations between BMI and creatinine, urea, and cystatin C on the 7th day after kidney transplantation (P<0.05). The sensitivity analysis further confirmed these correlations in different gender stratification, adolescents, and adults. However, the positive correlation with cystatin C was only significant in males. Additionally, after conducting smooth curve fitting analysis and threshold saturation analysis, it was revealed that the negative correlation between early renal function recovery was most significant when BMI was between 22.0-25.5kg/m2, and early postoperative renal function may be optimal when BMI was at 22.2kg/m2. Finally, the MR analysis confirmed a causal relationship between BMI and renal failure, as indicated by the IVW method (P=0.003), as well as the weighted median estimator (P=0.004). Conclusion This study on kidney transplant patients found that maintaining a BMI within the range of 22.0 to 25.5 kg/m2, with an optimal BMI of 22.2 kg/m2, improves early renal function recovery. This correlation holds true for different age groups and genders. Monitoring and controlling BMI in high-risk patients can enhance post-transplantation renal function.

Assessing Kidney Transplantation Using ECMO-Supported Donors Within a KDPI-Based Allocation System.

Organ donors supported by extracorporeal membrane oxygenation (ECMO) have historically been considered high-risk and are judiciously utilized. This study examines transplant outcomes using renal allografts from donors supported on ECMO for nondonation purposes. Retrospective review of the Gift of Life (Pennsylvania, New Jersey, Delaware) organ procurement organization database, cross-referenced to the Organ Procurement and Transplantation Network database, assessed kidney transplants using donors supported on venoarterial (VA) and venovenous (VV) ECMO for nondonation purposes. Transplants using VA- and VV-ECMO donors were compared with Kidney Donor Profile Index (KDPI)-stratified non-ECMO donors. Regression modeling of the entire ECMO and non-ECMO populations assessed ECMO as predictive of graft survival. Additional regression of the ECMO population alone assessed for donor features associated with graft survival. Seventy-eight ECMO donors yielded 128 kidney transplants (VA: 80, VV: 48). Comparing outcomes using these donors to kidney transplants using organs from KDPI-stratified non-ECMO donors, VA- and VV-ECMO donor grafts conferred similar rates of delayed graft function and posttransplant renal function to KDPI-matched non-ECMO counterparts. VA-ECMO kidneys demonstrated superior graft survival compared with the lowest-quality (KDPI 86%-100%) non-ECMO kidneys and similar graft survival to KDPI <85% non-ECMO kidneys. VV-ECMO showed inferior graft survival to all but the lowest-quality (KDPI 86%-100%) non-ECMO kidneys. VV-ECMO, but not VA-ECMO, was associated with increased risk of graft loss on multivariable regression (hazard ratios-VA: 1.02, VV: 2.18). Higher KDPI, advanced age, increased body mass index, hypertension, and diabetes were identified as high-risk features of ECMO donors. Kidney transplantation using appropriately selected ECMO donors can safely expand the donor pool. Ongoing studies are necessary to determine best practice patterns using kidneys from these donors.

Contrast-enhanced ultrasonography for identifying acute kidney injury in brain-dead donors.

Acute kidney injury (AKI) is frequently found in deceased donors; however, few studies have reported the use of imaging to detect and identify this phenomenon. The purpose of this study was to detect renal microcirculatory perfusion in brain-dead donors using contrast-enhanced ultrasonography (CEUS), investigate the value of CEUS in identifying AKI, and analyze the correlation between CEUS and preimplantation biopsy results and early post-transplant renal function of grafts. This prospective study recruited 94 kidneys from brain-dead donors (AKI =44, non-AKI =50) from August 2020 to November 2022. The inclusion criteria were age ≥18 years and brain death. The exclusion criteria encompassed donors maintained with extracorporeal membrane oxygenation (ECMO) and the presence of irregular kidney anatomy. The mean age of the donors was 45.1±10.4 [standard deviation (SD)] years, and the majority were male (86.2%). CEUS was performed prior to organ procurement, and time-intensity curves (TICs) were constructed. The time to peak (TTP) and peak intensity (PI) of kidney segmental artery (KA), kidney cortex (KC), and kidney medulla (KM) were calculated using TIC analysis. Arrival time (AT) of KA (P<0.001) and TTP of kidney cortex (TTPKC) (P<0.001) of the non-AKI group were significantly shorter than those of the AKI group. The PI of the KA (P=0.003), KM (P=0.005), and kidney cortex (PIKC; P<0.001) of the non-AKI group were significantly higher than those of the AKI group. Multivariable logistic regression analysis showed that serum creatinine [odds ratio (OR) =1.06; 95% CI: 1.03-1.1; P<0.001], TTPKC (OR =1.38; 95% CI: 1.03-1.84; P=0.03), and PIKC (OR =0.95; 95% CI: 0.91-1; P=0.046) were the independent factors of AKI. The area under the receiver operating characteristic curve (AUC) for identifying AKI for TTPKC and PIKC was 0.73 and 0.71, respectively. TTPKC showed a weak correlation with interstitial fibrosis (r=0.23; P=0.03), PIKC showed a weak correlation with arterial intimal fibrosis ((r=-0.29; P=0.004) and arteriolar hyalinosis (r=-0.27; P=0.008), and PIKC showed the strongest correlation with eGFR on postoperative day 7 (r=-0.46; P=0.046) in the donor kidneys with AKI. CEUS can be used to identify AKI in brain-dead donors. Furthermore, there is a correlation between CEUS-derived parameters and pretransplant biopsy results and early preimplantation renal function of grafts.

Impact of COVID-19 on renal transplant recipients

Introduction: It was essential to explore immunosuppressant management strategies and potential clinical variables associated with COVID-19 related mortality in order to provide insight for clinicians attempting to manage kidney transplant recipients during the ongoing severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) pandemic. Objectives: The aim of the study was to assess the impact of COVID-19 on post-transplant renal function and outcome of immunosuppressant management on COVID-19. Patients and Methods: This is a cross sectional observational study conducted from March 2020 to January 2022 in a tertiary care hospital in South India. Baseline characteristics, comorbidities, history of graft dysfunction, symptoms and immunosuppressant modification was noted. Outcomes of COVID-19 such as acute kidney injury (AKI), need for dialysis and post COVID-19 complications were noted. The statistics were expressed as percentage for categorical variables and mean ± SD for continuous variables. Results: Out of 400 renal transplant patients on regular follow up, 28 patients developed COVID-19. The incidence of AKI was 64.2%. Immunosuppressant dose modification was done in majority of patients [mycophenolate mofetil (28.5%), steroids (53.5%) and tacrolimus (39.2%)]. Outcomes included recovery from AKI in 61.1%, recovery from oxygen dependence in 100% patients with an overall mortality rate of 7.1% patients. About 17.8% patients developed post-COVID-19 complications. Conclusion: Immunosuppressant dose modification during COVID-19 could play a role in development of AKI; infection being an independent risk factor. Patients should be monitored for development of post-COVID-19 complications.

WTP2.10 A retrospective study of effect of donor obesity on fibrosis and kidney outcome in live donor kidney transplantation

Abstract Aims Donor obesity has increased over the last decade. The aim of this study was to assess the effect of donor obesity on fibrosis in pre-implantation biopsy and kidney outcomes in live kidney transplants. Methods A series of 288 live kidney donors between 1998 and 2010 were studied. The series was divided into three groups according to the donor Body Mass Index (BMI); Normal BMI 17-24.9 (n=119), overweight BMI 25–29.9 (n=118) and obese BMI ≥30 (n=51). Donor and recipient demographics were gathered and recipient post-transplant renal function up to five years was retrieved. Fibrosis level in pre-implantation biopsies was analysed and graft and recipient survival were assessed. Results Hypertension and live kidney donor profile index LKDPI were statistically significantly higher in obese donors compared with non-obese donors (p=0.004 and p&amp;lt;0.001 respectively). Donor creatinine levels for obese group were comparable to the other two groups over three post-operative years (p=0.933). Fibrosis analysis showed no statistically significant difference among the three BMI groups (p=0.063). Donor obese group had statistically significant higher 5 year graft and patient loss rate compared with non-obese BMI groups (p=0.018 and p=0.015 respectively). Recipient post-operative creatinine levels showed no statistically significant differences among the three BMI groups (p=0.393). Similarly, fibrosis in pre-implantation biopsies had no statistically significant impact on recipient post-operative creatinine levels (p=0.243). Conclusions Donor obesity has no significant impact on fibrosis in the pre-implantation biopsy and on recipient post-operative kidney function. However, Donor obesity results in lower five-year graft and patient survival rate.

Decreased survival of simultaneous heart-kidney transplant recipients in the new heart allocation era

In 2018, the United Network for Organ Sharing (UNOS) modified their heart allocation policy to reduce waitlist mortality. Rates of simultaneous heart-kidney transplant (SHKT) have dramatically increased in recent years, despite increased rates of post-transplant renal failure in the new policy era. This study sought to investigate the impact of the new allocation system on waitlist and post-transplant outcomes of simultaneous heart-kidney transplantation. Adult patients listed for SHKT between 2012 and 2021 were included. Patients were cross-validated across both Thoracic and Kidney UNOS databases to confirm accurate listing and transplant data. Patients were stratified according to listing era. The Fine and Gray model was used to assess waitlist outcomes and post-transplant renal graft function. Kaplan Meier analysis and Cox regression were used to compare post-transplant survival. A total of 2,588 patients were included, of whom 1,406 (54.1%) were listed between 2012 - 2018 (Era 1) and 1,182 (45.9%) between 2019 - 2021(Era 2). Era 2 was associated with increased likelihood of transplant (aSHR: 1.52; p<0.01) and decreased waitlist mortality (aSHR: 0.63; p<0.01). Post-transplant survival at 2 years was decreased in Era 2 (78.8% vs. 86.9%; p<0.01). Undersized hearts (HR: 2.02; p<0.01), use of extracorporeal membrane oxygenation (HR: 2.67; p<0.1), and transplants performed following the policy change (HR: 1.45; p=0.03) were associated with increased mortality. Actuarial survival (combined waitlist and post-transplant) was significantly lower in the modern era (71.6% vs. 62.2%; p=0.02). The allocation policy change has improved waitlist outcomes in patients listed for SHKT, but potentially at the cost of worsened post-transplant outcomes.

Graft function and incidence of cardiac allograft vasculopathy in donation after circulatory-determined death heart transplant recipients

Experience in donation after circulatory-determined death (DCD) heart transplantation (HTx) is expanding. There is limited information on the functional outcomes of DCD HTx recipients. We sought to evaluate functional outcomes in our cohort of DCD recipients. We performed a single-center, retrospective, observational cohort study comparing outcomes in consecutive DCD and donation after brain death (DBD) HTx recipients between 2015 and 2019. Primary outcome was allograft function by echocardiography at 12 and 24 months. Secondary outcomes included incidence of cardiac allograft vasculopathy, treated rejection, renal function, and survival. Seventy-seven DCD and 153 DBD recipients were included. There was no difference in left ventricular ejection fraction at 12 months (59% vs 59%, P = .57) and 24 months (58% vs 58%, P = .87). There was no significant difference in right ventricular function at 12 and 24 months. Unadjusted survival between DCD and DBD recipients at 5 years (85.7% DCD and 81% DBD recipients; P = .45) was similar. There were no significant differences in incidence of cardiac allograft vasculopathy (odds ratio 1.59, P = .21, 95% confidence interval 0.77-3.3) or treated rejection (odds ratio 0.60, P = .12, 95% confidence interval 0.32-1.15) between DBD and DCD recipients. Post-transplant renal function was similar at 1 and 2 years. In conclusion, cardiac allografts from DCD donors perform similarly to a contemporary population of DBD allografts in the medium term.

238-OR: Changes In Renal Function after Islet Transplantation in a Single-Centre Cohort in Canada over 20 Years

Islet transplantation (ITx) is an established treatment for recurrent, severe hypoglycemia in type 1 diabetes, but requires lifelong immunosuppression (IS) which can be nephrotoxic. We examined long term changes in renal function after ITx, through estimated GFR (eGFR), in a single centre cohort followed for up to 20 years. We used data from adults undergoing islet after kidney or ITx alone (94%) at the University of Alberta Hospital between March 11 1999 and Oct 1 2019 with &amp;gt;1 year of follow up. IS included tacrolimus and sirolimus/mycophenolate, balancing side effects with graft and renal function. We calculated individuals mean CKD EPI eGFR (ml/min/1.73m2) at baseline (≤1y pre transplant), 6m and yearly timepoints across follow up. We assessed the overall slope/year of eGFR against time from first transplant in 3 time periods; ≤1y, 1-5y and 5-20y, using mixed effects models. We also compared slopes between subjects with preserved (&amp;gt;60, n=217) vs. reduced (&amp;lt;60, n=38) eGFR at baseline. We included 255 adults (42% M) followed for 88.3m [50.2, 144.9] (median [IQR]). Whole cohort eGFR declined over follow up, most rapidly in the first year; -28.3 [-31.8, -24.5], with slower decline later post transplant 1-5y; -2.9 [-3.5, -2.3] and 5-20y; -1.2 [-1.4, -1.04]. Those with preserved baseline eGFR experienced steeper decline across all time phases as compared to those with reduced eGFR, with the steepest decline ≤1y post transplant (-29.8 [-33.8, -25.9], -18.3 [-27.8, -8.9], p=0.027). Between 5-20y post transplant renal function continued to decline slowly in those with preserved baseline eGFR but was stable in those with reduced baseline eGFR, (-1.4 [-1.6, -1.2], 0.2 [-0.3, 0.7] p&amp;lt;0.001). Nine (3.5%) developed ESRD. Initiation of IS associates with a rapid decline in eGFR the first year post ITx, with minimal decline beyond 5y. With careful IS management, rates of eGFR decline are not greater in those with reduced baseline eGFR. Effective IS regimens without nephrotoxicity remain an important goal. Disclosure A.L.J.Carr: None. A.Shapiro: n/a. P.A.Senior: Advisory Panel; Novo Nordisk Canada Inc., Consultant; Novo Nordisk Canada Inc., Bayer Inc., Viatris Inc., Vertex Pharmaceuticals Incorporated, ViaCyte, Inc., Insulet Corporation. B.A.Marfil-garza: None. Y.Ling: None. R.A.Oram: Consultant; Janssen Research &amp; Development, LLC, Research Support; Randox R &amp; D. A.Lam: None. B.L.Anderson: None. D.O'gorman: None. T.Kin: None. D.Bigam: None.

Evaluation of NAG, NGAL, and KIM-1 as Prognostic Markers of the Initial Evolution of Kidney Transplantation.

Kidney transplantation is the best option for end-stage chronic kidney disease. Transplant viability is conditioned by drugs' nephrotoxicity, ischemia-reperfusion damage, or acute rejection. An approach to improve graft survival is the identification of post-transplant renal function prognostic biomarkers. Our objective was to study three early kidney damage biomarkers (N-acetyl-d-glucosaminidase, NAG; neutrophil gelatinase-associated lipocalin, NGAL; and kidney injury molecule-1, KIM-1) in the initial period after transplantation and to identify possible correlations with main complications. We analysed those biomarkers in urine samples from 70 kidney transplant patients. Samples were taken on days 1, 3, 5, and 7 after intervention, as well as on the day that renal function stabilised (based on serum creatinine). During the first week after transplant, renal function improved based on serum creatinine evolution. However, increasing levels of biomarkers at different times during that first week could indicate tubular damage or other renal pathology. A relationship was found between NGAL values in the first week after transplantation and delayed graft function. In addition, higher NAG and NGAL, and lower KIM-1 values predicted a longer renal function stabilisation time. Therefore, urinary NAG, NGAL, and KIM-1 could constitute a predictive tool for kidney transplant complications, contributing to improve graft survival rates.

Association of fasting blood glucose variability with all-cause mortality in heart transplant recipients.

Fasting blood glucose (FBG) variability, an emerging marker of glycemic control, has been shown to be related to the risk of cardiovascular events and all-cause mortality in subjects with or without diabetes. However, whether FBG variability is independently associated with a higher all-cause mortality in heart transplant recipients remains unknown. We performed a retrospective cohort study including 373 adult recipients who survived for at least 1year after heart transplantation with a functioning graft and measured FBG more than three times within first year after transplantation. Multivariable adjusted Cox regression analyses were performed to assess the association between FBG variability and all-cause mortality. Patients were categorized into three groups according to the coefficient of variation of FBG level: ≤7.0%, 7.0%-13.5%, and >13.5%. During a median follow-up of 44.4months (interquartile range [IQR], 22.6-63.3months), 31 (8.3%) participants died. In univariate analyses, FBG variability was associated with an increased all-cause mortality (hazard ratio [HR]: 3.00, 95% confidence interval [CI]: 1.67, 5.38; p<.001). This association remained materially unchanged in the multivariable model adjusted for components of demographics, cardiovascular history and lifestyle, hospital information, immunosuppressive therapy, and post-transplant renal function (HR: 2.75, 95% CI: 1.43, 5.28; p=.004). After heart transplantation, high FBG variability is strongly and independently associated with an increased risk of all-cause mortality. Our findings suggest that FBG variability is a novel risk factor and prognostic marker for heart transplantation recipients in outpatient clinic.

MP31-15 BY DONOR FACTOR COMPARISON OF PRE-TRANSPLANT CT VOLUMETRY AND RENAL DYNAMIC SCINTIGRAPHY IN PREDICTING POST-TRANSPLANT RENAL FUNCTION IN LIVING RENAL TRANSPLANT DONORS

You have accessJournal of UrologyCME1 Apr 2023MP31-15 BY DONOR FACTOR COMPARISON OF PRE-TRANSPLANT CT VOLUMETRY AND RENAL DYNAMIC SCINTIGRAPHY IN PREDICTING POST-TRANSPLANT RENAL FUNCTION IN LIVING RENAL TRANSPLANT DONORS Hirohito Naito, Nobufumi Ueda, Tomoko Honda, Iori Matsuda, Yu Osaki, Yoichiro Tohi, Yuki Matsuoka, Takuma Kato, Homare Okazoe, Rikiya Taoka, and Mikio Sugimoto Hirohito NaitoHirohito Naito More articles by this author , Nobufumi UedaNobufumi Ueda More articles by this author , Tomoko HondaTomoko Honda More articles by this author , Iori MatsudaIori Matsuda More articles by this author , Yu OsakiYu Osaki More articles by this author , Yoichiro TohiYoichiro Tohi More articles by this author , Yuki MatsuokaYuki Matsuoka More articles by this author , Takuma KatoTakuma Kato More articles by this author , Homare OkazoeHomare Okazoe More articles by this author , Rikiya TaokaRikiya Taoka More articles by this author , and Mikio SugimotoMikio Sugimoto More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003264.15AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Renal dynamic scintigraphy (RDS) is used to evaluate renal function in donors, and the utility of CT volumetry (CTV) has recently been reported. Both techniques can be discordant, and it is not clear which test is more useful in which patients. To evaluated the correlation between predicted renal function by both examination and post-transplant renal function. Patient factors affecting the usefulness of both examinations were evaluated. METHODS: Of 117 renal transplant donors who underwent renal transplantation at our institution between April 30, 2008 and April 30, 2022, 113 patients who underwent RDS and CT prior to transplantation were included. Correlation coefficients and regression equations were obtained from post-transplant estimated GFR (eGFR) and pre-transplant residual renal function calculated from RDS and CTV, respectively. The difference between the post-transplant eGFR and the predicted eGFR from each regression equations were obtained for each case, and the examination with smaller difference was defined as the useful test for that case. Multiple logistic regression analysis using factor including age, sex, BMI, serum creatinine, blood pressure, and presence of diabetes mellitus, which are commonly evaluated before transplantation, was performed to determine factors affecting the usefulness of both examinations. RESULTS: The correlation coefficients between pre-transplant residual renal function calculated from RDS and CTV and post-transplant eGFR were 0.742 and 0.794. The median difference between predicted eGFR and post-transplant eGFR obtained from both regression equations was 3.97 and 3.19 ml/min/1.73 m2, and multiple logistic regression analysis showed that CTV was significantly more useful in patients with higher BMI (p<0.05). CONCLUSIONS: Pre-transplant residual renal function calculated from by RDS and CTV were both positively correlated with post-transplant renal function. The results suggest that CTV is more useful than RDS in patients with high BMI. Source of Funding: No funding is needed for this study © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e435 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Hirohito Naito More articles by this author Nobufumi Ueda More articles by this author Tomoko Honda More articles by this author Iori Matsuda More articles by this author Yu Osaki More articles by this author Yoichiro Tohi More articles by this author Yuki Matsuoka More articles by this author Takuma Kato More articles by this author Homare Okazoe More articles by this author Rikiya Taoka More articles by this author Mikio Sugimoto More articles by this author Expand All Advertisement PDF downloadLoading ...

Up-regulation of PRKDC was associated with poor renal dysfunction after renal transplantation: A multi-centre analysis.

Renal transplantation is the only efficacious treatment for end-stage kidney disease. However, some people have developed renal insufficiency after transplantation, the mechanisms of which have not been well clarified. Previous studies have focused on patient factors, while the effect of gene expression in the donor kidney on post-transplant renal function has been less studied. Donor kidney clinical data and mRNA expression status were extracted from the GEO database (GSE147451). Weight gene co-expression network analysis (WGCNA) and differential gene enrichment analysis were performed. For external validation, we collected data from 122 patients who accepted renal transplantation at several hospitals and measured the level of target genes by qPCR. This study included 192 patients from the GEO data set, and 13 co-expressed genes were confirmed by WGCNA and differential gene enrichment analysis. Then, the PPI network contained 17 edges as well as 12 nodes, and four central genes (PRKDC, RFC5, RFC3 and RBM14) were identified. We found by collecting data from 122 patients who underwent renal transplantation in several hospitals and by multivariate logistic regression that acute graft-versus-host disease postoperative infection, PRKDC [Hazard Ratio (HR) = 4.44; 95% CI = [1.60, 13.68]; p = 0.006] mRNA level correlated with the renal function after transplantation. The prediction model constructed had good predictive accuracy (C-index = 0.886). Elevated levels of donor kidney PRKDC are associated with renal dysfunction after transplantation. The prediction model of renal function status for post-transplant recipients based on PRKDC has good predictive accuracy and clinical application.

Relationship between donated kidney volume determined by ultrasound adjusted for clinical factors and 1-month and 1-year creatinine clearance: A retrospective study.

Graft volume as a surrogate of nephron numbers correlates with allograft function. The primary aim of this study was to correlate renal volume determined by ultrasound, adjusted to recipient clinical parameters in order to determine post-transplant renal function at the end of the first year. A total of 140 patients were enrolled in this study, including 75 males, with a total mean age of 41.2±13.5 years. Clinical data of all donors and recipients undergoing kidney transplantation at our institution between 2003 and 2019 were reviewed. The volume of transplanted kidney was measured by ultrasonography on the fifth day after the operation and correlated with recipients' clinical parameters and then adjusted with first-month and first-year post-transplantation creatinine clearance. The mean allograft volume measured using ultrasonography was 175.0±37.2 mL. Absolute donor kidney volume had a non-significant correlation with creatinine clearance at 1 month and at 1 year after transplantation. The kidney volume/recipient body weight ratio had a positive, and significant, correlation with creatinine clearance at 1 month and at 1 year after transplantation (r = 0.326, p<0.001, and r=0.183, p=0.038, respectively). Our data demonstrated that 12-month creatinine clearance is influenced by ratio of donated kidney volume/recipient body weight.

Intravoxel Incoherent Motion-Diffusion-Weighted MRI for Investigation of Delayed Graft Function Immediately after Kidney Transplantation.

Purpose A non-invasive way of assessing post-transplant renal graft function has been needed. This study aimed to assess the micro-structural and micro-functional status of graft kidneys by using intravoxel incoherent motion- (IVIM-) diffusion-weighted imaging (DWI) to investigate delayed graft function (DGF) immediately after transplantation. Method A prospective study was conducted on 37 patients, 14 with early graft function (EGF) and 23 with DGF (9 with complication, 14 without) who underwent IVIM-DWI, most often within 1-7 days after kidney transplantation. A total of 37 cases were collected and all the participants have been well-informed and signed their consents. In addition, the study conducted in this paper was approved by the Ethics Committee of Clinical Research, Taichung Veterans General Hospital (IRB number: CE14065). Using biexponential analysis of slow diffusion coefficient (Dslow), fast diffusion coefficient (Dfast), and perfusion fraction was performed. The apparent diffusion coefficient (ADC) was calculated by use of a monoexponential model. All parameters were measured from three different regions-of-interest (ROI), covering the entire renal parenchyma, cortex, and medulla. Results D slow, perfusion fraction, and ADC were significantly higher in patients with EGF than DGF (all p values values <0.001). Especially, ADC measured from ROI covering the entire kidney parenchyma had the best cut-off value (1.93μm2/msec) with the highest area under the receiver operating characteristic curve (AUC 0.943) in differentiating EGF from DGF. For analysis of pair-wise differences, only the perfusion fraction values, measured from the ROI covering the renal cortex, were significantly higher in 14 DGF patients with no complications than in the 9 DGF patients with complications, with the best cut-off value of 12.3% and the AUC of 0.844. Conclusion Noninvasive IVIM-DWI reliably differentiates DGF from EGF after kidney transplantation, and it may aid in identifying posttransplant complications and indications for renal biopsy.

Machine Learning–Based Ultrasound Radiomics for Evaluating the Function of Transplanted Kidneys

The aim of the study described here was to investigate the value of different machine learning models based on the clinical and radiomic features of 2-D ultrasound images to evaluate post-transplant renal function (pTRF). We included 233 patients who underwent ultrasound examination after renal transplantation and divided them into the normal pTRF group (group 1) and the abnormal pTRF group (group 2) based on their estimated glomerular filtration rates. The patients with abnormal pTRF were further subdivided into the non-severe renal function impairment group (group 2A) and the severe impairment group (group 2B). The radiomic features were extracted from the 2-D ultrasound images of each case. The clinical and ultrasound image features as well as radiomic features from the training set were selected, and then five machine learning algorithms were used to construct models for evaluating pTRF. Receiver operating characteristic curves were used to evaluate the discriminatory ability of each model. A total of 19 radiomic features and one clinical feature (age) were retained for discriminating group 1 from group 2. The area under the receiver operating characteristic curve (AUC) values of the models ranged from 0.788 to 0.839 in the test set, and no significant differences were found between the models (all p values >0.05). A total of 17 radiomic features and 1 ultrasound image feature (thickness) were retained for discriminating group 2A from group 2B. The AUC values of the models ranged from 0.689 to 0.772, and no significant differences were found between the models (all p values >0.05). Machine learning models based on clinical and ultrasound image features, as well as radiomics features, from 2-D ultrasound images can be used to evaluate pTRF.

Effect of Post-Transplant Cardiac Angiographic Procedures on Post-Transplant Renal Function

Cardiac interventions often are performed before and after renal transplant for coronary artery disease. The aim of this study was to investigate whether post-transplant cardiac coronary procedures affect post-transplant renal function. We retrospectively included renal transplant recipients who underwent renal transplant procedures at Baskent University between April 28, 1997 and January 20, 2020. We analyzed the effect of cardiac catheterization in renal transplant recipients between 6 and 12 months post-transplant with post-transplant renal function assessed by glomerular filtration rate (GFR). We compared the effect of the type of coronary intervention on GFR change in group 1, whereby group 1 was divided into 2 subgroups (coronary artery bypass grafting [CABG] and stenting). Group 1 included patients who underwent cardiac intervention, whereas group 2 included those who had not undergone cardiac intervention. In all, 108 patients underwent coronary angiography; 45 (41.7%) had normal coronaries or minimal coronary artery disease (CAD); 37 (34.3%) underwent stent implantation; 26 (24.1%) underwent CABG. The mean post- transplantation GFR of all patients after cardiac catheterization was 84.26+25.91 (mL/min/1.73 m2). The final, after 12 months mean GFR of all patients was 69.55+27.05. The final GFR was significantly lower than the initial post-renal GFR value in patients who underwent cardiac intervention but not in non-intervened patients. Invasive cardiac revascularization procedures showed a negative effect on post-transplant renal function in renal transplant recipients. All renal transplant recipients who underwent cardiac intervention survived the intervention, and there was no mortality. The reason for this outcome was assumed to be because of the short follow-up period.

Histological evaluation of ischemic alterations in donors after cardiac death: A useful tool to predict post-transplant renal function.

Kidneys retrieved from donors after cardiac death (DCD) pose significant challenges from a clinical and technical point of view, undergoing a variable degree of ischemia-reperfusion injury. At present, the utilization of kidneys is assessed according to the Karpinski score, which does not take into account the ischemic insult and does not predict the functional recovery of the organ once transplanted. Therefore, the correlation between biopsy results and post-transplant graft function is still debated. In this study we examined kidney biopsies from DCD donors; we calculated the Karpinski score and subsequently identified and quantified the ischemic lesions in the glomerular, interstitial, and tubular compartments. These same lesions were quantified in kidney biopsies from donors after brain death (DBD) in a case-control analysis. The collected data were correlated with the clinical data of the donors and the post-transplant follow-up. Proximal tubule alterations are crucial in ischemia-reperfusion damage, showing precise histological alterations, which are more frequent in DCD than in DBD donors and are statistically correlated with functional recovery of the organ. Quantification of ischemic tubular lesions in biopsies of kidneys from DCD donors is a useful tool for predicting post-transplant renal function and a valid parameter for assessing the quality of the graft.

Contemporary risk factors for ureteral stricture following renal transplantation.

Allograft ureteral strictures after renal transplantation impact graft function and increase patient morbidity. They can be challenging to treat and may require complex surgical repair. Therefore, the objective of this study was to identify contemporary risk factors for the development of post-renal transplant ureteral strictures. A retrospective analysis was performed on all renal transplant patients at Vancouver General Hospital from 2008-2019. Demographics, clinical parameters, and outcomes were compared between patients who did and did not develop ureteral strictures. Putative risk factors for ureteral stricture were analyzed using logistic regression. A total of 1167 patients were included with a mean followup of 61.9±40.8 months. Ureteral strictures occurred in 25 patients (2.1%). Stricture patients had no demographic differences compared to non-stricture patients but had significantly higher rates of postoperative complications, longer hospital stays, and decreased renal function one year post-transplant (all p<0.05). On multivariable analysis, cold ischemia time >435 minutes (odds ratio [OR] 43.9, confidence interval [CI] 1.6-1238.8, p=0.027), acute rejection (OR 3.0, CI 1.1-7.4, p=0.027), and postoperative complications (OR 112.4, CI 2.4-5332.6, p=0.016) were risk factors for stricture. Renal transplant patients with ureteral stricture experience greater morbidity and reduced post-transplant renal function compared to non-stricture patients. Our findings support attempts to reduce cold ischemia time, acute rejection, and postoperative complications to mitigate this potential complication. Our study is limited by the low incidence of ureteral stricture resulting in a small sample of stricture patients. Future research in a larger, multicenter setting is warranted.

Deep Learning Algorithms for the Prediction of Posttransplant Renal Function in Deceased-Donor Kidney Recipients: A Preliminary Study Based on Pretransplant Biopsy.

BackgroundPosttransplant renal function is critically important for kidney transplant recipients. Accurate prediction of graft function would greatly help in deciding acceptance or discard of allocated kidneys.Methods: Whole-slide images (WSIs) of H&E-stained donor kidney biopsies at × 200 magnification between January 2015 and December 2019 were collected. The clinical characteristics of each donor and corresponding recipient were retrieved. Graft function was indexed with a stable estimated glomerular filtration rate (eGFR) and reduced graft function (RGF). We used convolutional neural network (CNN)-based models, such as EfficientNet-B5, Inception-V3, and VGG19 for the prediction of these two outcomes.ResultsIn total, 219 recipients with H&E-stained slides of the donor kidneys were included for analysis [biopsies from standard criteria donor (SCD)/expanded criteria donor (ECD) was 191/28]. The results showed distinct improvements in the prediction performance of the deep learning algorithm plus the clinical characteristics model. The EfficientNet-B5 plus clinical data model showed the lowest mean absolute error (MAE) and root mean square error (RMSE). Compared with the clinical data model, the area under the receiver operating characteristic (ROC) curve (AUC) of the clinical data plus image model for eGFR classification increased from 0.69 to 0.83. In addition, the predictive performance for RGF increased from 0.66 to 0.80. Gradient-weighted class activation mappings (Grad-CAMs) showed that the models localized the areas of the tubules and interstitium near the glomeruli, which were discriminative features for RGF.ConclusionOur results preliminarily show that deep learning for formalin-fixed paraffin-embedded H&E-stained WSIs improves graft function prediction accuracy for deceased-donor kidney transplant recipients.