Reproducibility of Deceased Donor Kidney Procurement Biopsies

High-Functioning Deceased Donor Kidney Transplant System Characteristics: The British Columbia Experience With an Opt-In System

Rationale & Objective

A high level of cooperation between organ procurement organizations and transplant programs may help maximize use of deceased donor kidneys. The practices that are essential for a high functioning organ donation and transplant system remain uncertain. We sought to report metrics of organ donation and transplant performance in British Columbia, Canada, and to assess the association of specific policies and practices that contribute to the system's performance.

Study Design

A retrospective observational study.

Setting & Participants

Referred deceased organ donors in British Columbia were used in the study from January 1, 2016, to December 31 2019.

Exposures

Provincial, organ procurement organization, and center level policies were implemented to improve donor referral and organ utilization.

Outcomes

Assessment of donor and kidney utilization along steps of the critical pathway for organ donation.

Analytical Approach

Deceased donors were classified according to the critical pathway for organ donation and key donation and transplant metrics were identified.

Results

There were 1,948 possible donors referred. Of 1,948, 754 (39%) were potential donors. Of 754 potential donors, 587 (78%) were consented donors. Of 587 consented donors, 480 (82%) were eligible kidney donors. Of 480 eligible kidney donors, 438 (91%) were actual kidney donors. And of 438 actual kidney donors, 432 (99%) were utilized kidney donors. One-year all-cause allograft survival was 95%. Practices implemented to improve the system's performance included hospital donor coordinators, early communication between the organ procurement organization and transplant nephrologists, dedicated organ recovery and implant surgeons, aged-based kidney allocation, and hospital admission of recipients before kidney recovery.

Limitations

Assignment of causality between individual policies and practices and organ donation and utilization is limited in this observational study.

Conclusions

In British Columbia, consent for donation, utilization of donated kidneys, and transplant survival are exceptionally high, suggesting the importance of an integrated deceased donor and kidney transplant service.

Missing the Match: A National Survey Investigating Education in Renal Donor-Recipient Matching

PURPOSE

Clinical judgment in renal donor organ and recipient selection is gained through fellowship and mentorship in early career. We aim to understand the past and current state of organ acceptance education.

METHODS

We developed and distributed an anonymous, national survey to American Society of Transplant Surgeons faculty members and transplant surgery fellows in 2022. Survey questions explored in detail the evaluation of organ offers, the extent of formal education in organ evaluation, and attitudes regarding training adequacy.

FINDINGS

Ninety-eight attending surgeons (65 men, 25 women, and 3 nonbinary) and 38 fellows (25 men, 6 women, and 2 nonbinary) responded. Seventy-eight percent of attending surgeons and 6% of fellows take primary organ offers. Forty-four percent of fellows report no didactic education in donor evaluation and recipient selection. Fellows report that discussion with attending surgeons (37.2%) and independent study of the literature (35.4%) are their primary modes of learning. Fellows call for additional clinical decision-making experience (47.3%), further didactic sessions (44.7%), and additional discussions with faculty (44.7%). Sixty-four percent of fellows and 55% of attendings felt their training provided adequate education about donor selection.

CONCLUSION

Our responses suggest gaps in education regarding donor and recipient selection. Increased clinical experience and standardized education at the national level represent opportunities for improvement.

Postreperfusion Renal Allograft Biopsy Predicts Outcome of Single-Kidney Transplantation: A 10-Year Observational Study in China

Introduction

Biopsy findings often lead to the discard of many donor kidneys although their clinical value is not fully understood. We investigated the predictive value of postreperfusion biopsy on long-term allograft outcome after single-kidney transplantation.

Methods

We retrospectively evaluated the significance of histologic findings, read by experienced renal pathologists, in 461 postreperfusion biopsy specimens collected from 2010 to 2017 after deceased donor renal transplant; and performed time-to-event analyses to determine the association between histology and hazard of death-censored graft failure. Recipients were followed-up with over a median time of 6.8 (range, 0.2-11.9) years. We assessed specimens using the Remuzzi score (scale of 0-12) and categorized them into low-score (≤3) and high-score (>3) groups. Kappa coefficients were calculated to assess agreement in procurement versus reperfusion biopsies.

Results

High Remuzzi score kidneys came from older donors with a higher incidence of hypertension, higher final creatinine, death from cerebrovascular disease, expanded criteria donor, and a higher kidney donor risk index (KDRI) (all P < 0.001). In adjusted analyses, Remuzzi score was independently associated with death-censored graft failure (hazard ratio [HR] 1.389 for each 1 score rise in Remuzzi score, 95% confidence interval 1.181-1.633, P < 0.001). Overall histologic agreement (procurement biopsy versus reperfusion biopsy) was kappa = 0.137.

Conclusion

Our findings suggest that postreperfusion biopsy is associated with long-time graft outcomes after transplant from a deceased donor. Agreement between procurement and reperfusion biopsy was found to be low. Prospective trials are necessary to optimize procurement biopsy practices.

Association between Kidney Donor Risk Index, kidney graft function and histological changes in early post-transplant graft biopsy

Background

Proper assessment of donor organ quality is crucial for optimal kidney allocation and best long-term outcomes. The aim of this study was to analyze the association between the Kidney Donor Risk Index (KDRI) and histological parameters in early post-transplant graft biopsy in a Polish cohort of kidney transplant recipients.

Methods

In 418 consecutive kidney transplant recipients, a histological evaluation of very early [at median 11 (9-13) post-transplant day] protocol core needle biopsy was performed and analyzed according to the Banff classification. Subjects were divided into quartiles of the KDRI value. Kidney graft function, patient and graft survival were also analyzed over a median follow-up period of 44 (26-56) months.

Results

There was a significant trend toward greater intensity of chronic histology changes along the KDRI quartiles (χ2 = 20.8; P < .001), including interstitial fibrosis, tubular atrophy, mesangial matrix increase and arteriolar hyalinosis. Stepwise multivariate regression analysis revealed that only higher KDRI value independently increased the severity of chronic graft injury (rpartial = 0.340, P < .001). KDRI values were valuable in the determination of both early and long-term graft function.

Conclusion

The KDRI values correlate with chronic histological changes found in early post-implantation kidney biopsies and can also be helpful in the prediction of graft outcome.

Expression and correlation of the Pi3k/Akt pathway and VEGF in oral submucous fibrosis

Oral submucous fibrosis (OSF) has a high incidence in Asia countries, but its underlying molecular mechanism was not exploited completely. In this research, we investigated the expression of the phosphatidyl inositol 3-kinase (Pi3k)/protein kinase B (Akt) pathway and vascular endothelial growth factor (VEGF) in oral submucosal fibrosis, explore the correlation between the Pi3k/Akt pathway and VEGF, and identify the mechanisms involved in OSF. The pathological changes and fibrosis stages of OSF tissues (n = 30, 10 each of early, moderate and advanced OSF) were determined using Haematoxylin-eosin staining (HE) and Masson staining, respectively. Collagen type I (Col-I), Pi3k, Akt, VEGF, TGF-β and p-Akt expression was detected using immunohistochemistry, qPCR and WB. The correlation between Pi3k, Akt and VEGF was analysed. Col-I expression increased as OSF progressed. However, their expression was downregulated in normal and moderate to advanced OSF tissues. VEGF expression positively correlated with Pi3k and Akt expression. VEGF expression correlated positively and negatively with the Pi3k inhibitor, LY294002 below and above a concentration of 10 μM, respectively. VEGF expression correlated positively with the Pi3k/Ak activator, IGF-1. Due to the synergistic effect between Pi3k/Akt pathway and VEGF on OSF lesions and fibrosis process, targeted Pi3k/Akt pathway regulation can induce VEGF expression and improve ischemia, ultimately treating OSF.

European Society for Organ Transplantation (ESOT)-TLJ 3.0 Consensus on Histopathological Analysis of Pre-Implantation Donor Kidney Biopsy: Redefining the Role in the Process of Graft Assessment

The ESOT TLJ 3.0. consensus conference brought together leading experts in transplantation to develop evidence-based guidance on the standardization and clinical utility of pre-implantation kidney biopsy in the assessment of grafts from Expanded Criteria Donors (ECD). Seven themes were selected and underwent in-depth analysis after formulation of PICO (patient/population, intervention, comparison, outcomes) questions. After literature search, the statements for each key question were produced, rated according the GRADE approach [Quality of evidence: High (A), Moderate (B), Low (C); Strength of Recommendation: Strong (1), Weak (2)]. The statements were subsequently presented in-person at the Prague kick-off meeting, discussed and voted. After two rounds of discussion and voting, all 7 statements reached an overall agreement of 100% on the following issues: needle core/wedge/punch technique representatively [B,1], frozen/paraffin embedded section reliability [B,2], experienced/non-experienced on-call renal pathologist reproducibility/accuracy of the histological report [A,1], glomerulosclerosis/other parameters reproducibility [C,2], digital pathology/light microscopy in the measurement of histological variables [A,1], special stainings/Haematoxylin and Eosin alone comparison [A,1], glomerulosclerosis reliability versus other histological parameters to predict the graft survival, graft function, primary non-function [B,1]. This methodology has allowed to reach a full consensus among European experts on important technical topics regarding pre-implantation biopsy in the ECD graft assessment.

Influence of organ quality on the observed association between deceased donor kidney procurement biopsy findings and graft survival

Deceased donor kidney procurement biopsies findings are the most common reason for kidney discard. Retrospective studies have found inconsistent associations with post-transplant outcomes but may have been limited by selection bias because kidneys with advanced nephrosclerosis from high-risk donors are typically discarded. We conducted a retrospective cohort study of kidneys transplanted in the United States from 2015 to 2019 with complete biopsy data available, defining "suboptimal histology" as glomerulosclerosis ≥11%, IFTA ≥mild, and/or vascular disease ≥mild. We used time-to-event analyses to determine the association between suboptimal histology and death-censored graft failure after stratification by kidney donor profile index (KDPI) (≤35%, 36%-84%, ≥85%) and final creatinine (<1 mg/dl, 1-2 mg/dl, >2 mg/dl). Among 30 469 kidneys included, 36% had suboptimal histology. In adjusted analyses, suboptimal histology was associated with death-censored graft failure among kidneys with KDPI 36-84% (HR 1.22, 95% CI 1.09-1.36), but not KDPI≤35% (HR 1.24, 0.94-1.64) or ≥ 85% (HR 0.99, 0.81-1.22). Similarly, suboptimal histology was associated with death-censored graft failure among kidneys from donors with creatinine 1-2 mg/dl (HR 1.39, 95% CI 1.20-1.60) but not <1 mg/dl (HR 1.07, 0.93-1.23) or >2 mg/dl (HR 0.95, 0.75-1.20). The association of procurement histology with graft longevity among intermediate-quality kidneys that were likely to be both biopsied and transplanted suggests biopsies provide independent organ quality assessments.

The role of bypass filters in deceased donor kidney allocation in the United States

Kidney transplant centers set organ offer filters enabling all candidates at their center to be bypassed during allocation of deceased donor kidneys from the UNOS Organ Center. These filters aim to increase allocation efficiency by preemptively screening out offers unlikely to be accepted. National data were used to compare filter settings of 175 centers in 2007 and in 2019. We examined characteristics of centers whose settings became increasingly restrictive over time, and associations between filter settings and organ offer acceptance. Overall, centers became more open to receiving offers over time, from a median 62% of filters open to receiving national offers in 2007 to 73% in 2019. Intravenous drug use filter settings changed most, from 63 to 153 willing centers. Centers with more open filter settings had higher transplant volume and offer acceptance ratios across all risk categories despite preemptively screening out fewer offers compared to centers with less open settings, but similar transplant rates. There was significant geographic heterogeneity in the distribution of centers with more open filter settings. Current center bypass filters may impact patients' access to transplantation without achieving their full potential for improving allocation efficiency.

High-speed light-sheet microscopy for the in-situ acquisition of volumetric histological images of living tissue

Histological examinations typically require the excision of tissue, followed by its fixation, slicing, staining, mounting and imaging, with timeframes ranging from minutes to days. This process may remove functional tissue, may miss abnormalities through under-sampling, prevents rapid decision-making, and increases costs. Here, we report the feasibility of microscopes based on swept confocally aligned planar excitation technology for the volumetric histological imaging of intact living tissue in real time. The systems' single-objective, light-sheet geometry and 3D imaging speeds enable roving image acquisition, which combined with 3D stitching permits the contiguous analysis of large tissue areas, as well as the dynamic assessment of tissue perfusion and function. Implemented in benchtop and miniaturized form factors, the microscopes also have high sensitivity, even for weak intrinsic fluorescence, allowing for the label-free imaging of diagnostically relevant histoarchitectural structures, as we show for pancreatic disease in living mice, for chronic kidney disease in fresh human kidney tissues, and for oral mucosa in a healthy volunteer. Miniaturized high-speed light-sheet microscopes for in-situ volumetric histological imaging may facilitate the point-of-care detection of diverse cellular-level biomarkers.

The Role of Procurement Biopsies in Kidney Acceptance Decision Making and Kidney Discard: Perceptions of Physicians, Nurse Coordinators, and OPO Staff and Directors

Procurement biopsies suffer from challenges with quality and reproducibility and are linked to kidney discard. Nonetheless, procurement biopsies are obtained for the majority of kidneys in the United States, and biopsy findings are commonly relied upon in kidney acceptance decisions.

Clinically adjudicated deceased donor acute kidney injury and graft outcomes

BACKGROUND

Acute kidney injury (AKI) in deceased donors is not associated with graft failure (GF). We hypothesize that hemodynamic AKI (hAKI) comprises the majority of donor AKI and may explain this lack of association.

METHODS

In this ancillary analysis of the Deceased Donor Study, 428 donors with available charts were selected to identify those with and without AKI. AKI cases were classified as hAKI, intrinsic (iAKI), or mixed (mAKI) based on majority adjudication by three nephrologists. We evaluated the associations between AKI phenotypes and delayed graft function (DGF), 1-year eGFR and GF. We also evaluated differences in urine biomarkers among AKI phenotypes.

RESULTS

Of the 291 (68%) donors with AKI, 106 (36%) were adjudicated as hAKI, 84 (29%) as iAKI and 101 (35%) as mAKI. Of the 856 potential kidneys, 669 were transplanted with 32% developing DGF and 5% experiencing GF. Median 1-year eGFR was 53 (IQR: 41-70) ml/min/1.73m2. Compared to non-AKI, donors with iAKI had higher odds DGF [aOR (95%CI); 4.83 (2.29, 10.22)] and had lower 1-year eGFR [adjusted B coefficient (95% CI): -11 (-19, -3) mL/min/1.73 m2]. hAKI and mAKI were not associated with DGF or 1-year eGFR. Rates of GF were not different among AKI phenotypes and non-AKI. Urine biomarkers such as NGAL, LFABP, MCP-1, YKL-40, cystatin-C and albumin were higher in iAKI.

CONCLUSION

iAKI was associated with higher DGF and lower 1-year eGFR but not with GF. Clinically phenotyped donor AKI is biologically different based on biomarkers and may help inform decisions regarding organ utilization.

Deceased Donor Procurement Biopsy Practices, Interpretation, and Histology-Based Decision Making: A Survey of U.S. Transplant Centers

Introduction

Methods

Results

Conclusion

Development of Planar Illumination Strategies for Solving Mysteries in the Sub-Cellular Realm

Optical microscopy has vastly expanded the frontiers of structural and functional biology, due to the non-invasive probing of dynamic volumes in vivo. However, traditional widefield microscopy illuminating the entire field of view (FOV) is adversely affected by out-of-focus light scatter. Consequently, standard upright or inverted microscopes are inept in sampling diffraction-limited volumes smaller than the optical system's point spread function (PSF). Over the last few decades, several planar and structured (sinusoidal) illumination modalities have offered unprecedented access to sub-cellular organelles and 4D (3D + time) image acquisition. Furthermore, these optical sectioning systems remain unaffected by the size of biological samples, providing high signal-to-noise (SNR) ratios for objective lenses (OLs) with long working distances (WDs). This review aims to guide biologists regarding planar illumination strategies, capable of harnessing sub-micron spatial resolution with a millimeter depth of penetration.

Long-standing donor diabetes and pathologic findings are associated with shorter allograft survival in recipients of kidney transplants from diabetic donors

Approximately 6% of deceased kidney donors (DKDs) are diabetic; their kidneys may be associated with worse allograft survival, but published studies suggest that recipient diabetes status has a greater impact on mortality and survival. Since biopsy findings are the most common reason for organ discard, we sought to understand histologic and clinical factors that influence graft survival in patients who receive a kidney from a diabetic DKD. We retrospectively reviewed our institutional experience from 2005 to 2019, and re-evaluated pre-implantation and earliest post-transplant biopsies. Histologic findings were compared against a control cohort of non-diabetic DKD. Of 829 adult DKD transplants, 37 (4.5%) came from diabetic donors. There was no significant difference in diabetic vs. non-diabetic DKD graft survival for all-comers; however, when stratified by duration of donor diabetes, donor diabetes ≥6 years was associated with graft failure. In 25 patients with post-transplant biopsies available, diabetic DKD allografts had significantly greater non-glomerular chronic injury than non-diabetic DKD allografts. Moderate arteriolar hyalinosis (in 24%), moderate tubular atrophy and interstitial fibrosis (IFTA, in 36%), and diabetic glomerulopathy (in 24%) on early post-transplant biopsy were associated with allograft failure. Pre-implantation frozen section discrepancies were more common in long-standing donor diabetes, and arteriolar hyalinosis and IFTA scores on frozen accurately prognosticated graft loss. There was no morphologic improvement in lesions of diabetic nephropathy on short-term follow-up. In conclusion, donor diabetes ≥6 years, and histologic findings on frozen section and early post-transplant biopsy are associated with diabetic DKD allograft loss.

Number of Donor Renal Arteries and Early Outcomes after Deceased Donor Kidney Transplantation

Background

Anatomic abnormalities increase the risk of deceased donor kidney discard, but their effect on transplant outcomes is understudied. We sought to determine the effect of multiple donor renal arteries on early outcomes after deceased donor kidney transplantation.

Methods

For this retrospective cohort study, we identified 1443 kidneys from 832 deceased donors with ≥1 kidney transplanted at our center (2006-2016). We compared the odds of delayed graft function and 90-day graft failure using logistic regression. To reduce potential selection bias, we then repeated the analysis using a paired-kidney cohort, including kidney pairs from 162 donors with one single-artery kidney and one multiartery kidney.

Results

Of 1443 kidneys included, 319 (22%) had multiple arteries. Multiartery kidneys experienced longer cold ischemia time, but other characteristics were similar between groups. Delayed graft function (50% multiartery versus 45% one artery, P=0.07) and 90-day graft failure (3% versus 3%, P=0.83) were similar between groups before and after adjusting for donor and recipient characteristics. In the paired kidney analysis, cold ischemia time was significantly longer for multiartery kidneys compared with single-artery kidneys from the same donor (33.5 versus 26.1 hours, P<0.001), but delayed graft function and 90-day graft failure were again similar between groups.

Conclusions

Compared with single-artery deceased donor kidneys, those with multiple renal arteries are harder to place, but experience similar delayed graft function and early graft failure.

Declined Offers for Deceased Donor Kidneys Are Not an Independent Reflection of Organ Quality

Background

Deceased donor kidney offers are frequently declined multiple times before acceptance for transplantation, despite significant organ shortage and long waiting times. Whether the number of times a kidney has been declined, reflecting cumulative judgments of clinicians, is associated with long-term transplant outcomes remains unclear.

Methods

In this national, retrospective cohort study of deceased donor kidney transplants in the United States from 2008 to 2015 (n=78,940), we compared donor and recipient characteristics and short- and long-term graft and patient survival outcomes grouping by the sequence number at which the kidney was accepted for transplantation. We compared outcomes for kidneys accepted within the first seven offers in the match-run, after 8-100 offers, and for hard-to-place kidneys distinguishing those requiring >100 and >1000 offers before acceptance.

Results

Harder-to-place kidneys had lower donor quality and higher rates of delayed graft function (46% among kidneys requiring >1000 offers before acceptance versus 23% among kidneys with ≤7 offers). In unadjusted models, later sequence groups had higher hazard of all-cause graft failure, death-censored graft failure, and patient mortality; however, these associations were attenuated after adjusting for Kidney Donor Risk Index (KDRI). After adjusting for donor factors already taken into consideration during allocation, and recipient factors associated with long-term outcomes, graft, and patient survival outcomes were not significantly different for the hardest-to-place kidneys compared with the easiest-to-place kidneys, with the exception of death-censored graft failure (adjusted hazard ratio, 1.16, 95% CI, 1.05 to 1.28).

Conclusion

Late sequence offers may represent missed opportunities for earlier successful transplant for the higher-priority waitlisted candidates for whom the offers were declined.

Role of deceased donor kidney procurement biopsies in organ allocation

PURPOSE OF REVIEW

There has been an increased emphasis by the transplant community and the federal government to increase the utilization of deceased donor kidneys. Procurement biopsies during allocation are the most common reason for kidney discards. This manuscript reviews the evidence of procurement biopsies practices and utility.

RECENT FINDINGS

Procurement biopsies are performed in over half of all the kidneys recovered in the United States and account for more than one third of the kidney discards. However, there is a significant heterogeneity across the organ procurement organizations regarding the indications for biopsy, biopsy techniques and their reporting. Procurement biopsy findings are not reproducible and poorly correlate to postimplantation histology, although reasons for these limitations are not clear. Procurement biopsy findings are not associated with posttransplant outcomes after accounting for readily available donor clinical characteristics.

SUMMARY

Procurement biopsies contribute to deceased donor kidney discards but do not predict posttransplant outcomes. Research to establish the best practices for procurement biopsies is needed to improve organ utilization.

Variations in deceased donor kidney procurement biopsy practice patterns: A survey of U.S. organ procurement organizations

BACKGROUND

Procurement biopsies have become a common practice in the evaluation and allocation of deceased donor kidneys in the United States despite questions about their value and reproducibility. We sought to determine the extent of OPO-level differences in criteria used to decide which deceased donor kidneys undergo a procurement biopsy and to assess the degree of variability in procurement biopsy technique and interpretation across OPOs.

METHODS

Each of the country's 58 OPOs were invited to participate in the survey. OPOs were divided into two groups based on organ availability ratio and deceased donor kidney discard rate.

RESULTS AND CONCLUSIONS

Fifty-out-of-fifty-eight invited OPOs (86% response rate) responded to the survey between November 2020 and December 2020. Thirty (60%) OPOs reported that they have formal criteria for performing kidney procurement biopsy, but for 29 of these OPOs, transplant centers can request biopsy on kidneys that do not meet criteria. OPOs used a total of seven different variables and 12 different numerical thresholds to define impaired kidney function that would prompt a procurement biopsy. Additionally, wide variability was seen in biopsy technique and procedures for biopsy interpretation and reporting of findings to transplant programs. These findings identify a clear opportunity for standardization of procurement biopsies to best practices.

Association between procurement biopsy findings and deceased donor kidney outcomes: a paired kidney analysis

Unfavourable procurement biopsy findings are the most common reason for deceased donor kidney discard in the United States. We sought to assess the association between biopsy findings and post-transplant outcomes when donor characteristics are accounted for. We used registry data to identify 1566 deceased donors of 3132 transplanted kidneys (2015-2020) with discordant right/left procurement biopsy classification and performed time-to-event analyses to determine the association between optimal histology and hazard of death-censored graft failure or death. We then repeated all analyses using a local cohort of 147 donors of kidney pairs with detailed procurement histology data available (2006-2016). Among transplanted kidney pairs in the national cohort, there were no significant differences in incidence of delayed graft function or primary nonfunction. Time to death-censored graft failure was not significantly different between recipients of optimal versus suboptimal kidneys. Results were similar in analyses using the local cohort. Regarding recipient survival, analysis of the national, but not local, cohort showed optimal kidneys were associated with a lower hazard of death (adjusted HR 0.68, 95% CI 0.52-0.90, P = 0.006). In conclusion, in a large national cohort of deceased donor kidney pairs with discordant right/left procurement biopsy findings, we found no association between histology and death-censored graft survival.

Outcome of kidney transplantation from very senior donors in Switzerland - a national cohort study

Kidney transplantation from older and marginal donors is effective to confront organ shortage. However, limitations after transplantation of kidneys from very marginal kidney donors remain unclear. We compared patient and graft outcome, achieved allograft function and quality of life of renal transplantations from Very Senior Donors (VSD, defined as donors aged 70 years and older) with Senior Donors (SD, aged 60-70 years) and Regular Donors (RD, aged younger than 60 years) in Switzerland. We evaluated the outcome of 1554 adult recipients of deceased donor kidney transplantations from 05/2008 to 12/2019; median follow-up was 4.7 years. Failure-free survival (freedom from graft loss or death), glomerular filtration rate (eGFR), and quality of life at 12 months were analyzed for RD (reference group, n = 940), SD (n = 404), and VSD (n = 210). Failure-free survival decreased with increasing donor age, mainly attributable to premature graft loss. Still, overall 5-year failure-free survival reached 83.1%, 81.0%, and 64.0% in the RD, SD, and VSD subgroups, respectively. eGFR 12 months post-transplantation was significantly higher in RD compared with SD and VSD. The acceptance rate of donor candidates for kidney TPL was 78% for the entire cohort (87% for RD, 79% for SD, and 56% for VSD). Deceased donor kidney transplantation from donors aged 70 years or older is associated with an inferior, yet acceptable failure-free outcome, with sustained quality of life.

Preimplantation Histological Score Associates with 6-Month GFR in Recipients of Perfused, Older Kidney Grafts: Results from a Pilot Study

BACKGROUND

Biopsy-guided selection of older kidneys safely expands the organ pool, and pretransplant perfusion improves the preservation of these fragile organs. Herein, we studied morphofunctional variables associated with graft outcomes in perfused, histologically evaluated older kidneys.

METHODS

This single-center prospective cohort pilot study evaluated the relationships between preimplantation histologic scores and renal perfusion parameters during hypothermic, pulsatile, machine perfusion (MP) and assessed whether these morphofunctional parameters associated with GFR (iohexol plasma clearance) at 6 months after transplantation in 20 consecutive consenting recipients of a biopsy-guided single or dual kidney transplant from >60-year-old deceased donors.

RESULTS

The donor and recipient age was 70.4 ± 6.5 and 63.6 ± 7.9 years (p = 0.005), respectively. The kidney donor profile index (KDPI) was 93.3 ± 8.4% (>80% in 19 cases), histologic score 4.4 ± 1.4, and median (IQR) cold ischemia time 19.8 (17.8-22.8 h; >24 h in 5 cases). The 6-month GFR was 41.2 (34.9-55.7) mL/min. Vascular resistances positively correlated with global histologic score (p = 0.018) at MP start and then decreased from 0.88 ± 0.43 to 0.36 ± 0.13 mm Hg/mL/min (p < 0.001) in parallel with a three-fold renal flow increase from 24.0 ± 14.7 to 74.7 ± 31.8 mL/min (p < 0.001). Consistently, vascular resistance reductions positively correlated with global histologic score (p = 0.009, r = -0.429). Unlike KDPI or vascular resistances, histologic score was independently associated with 6-month GFR (beta standardized coefficient: -0.894, p = 0.005).

CONCLUSIONS

MP safely improves graft perfusion, particularly in kidneys with severe histologic changes that would not be considered for transplantation because of high KDPI. The preimplantation histologic score associates with the functional recovery of older kidneys even in the context of a standardized program of pulsatile perfusion.

Impact of Deceased Donor Kidney Procurement Biopsy Technique on Histologic Accuracy

Introduction

The factors that influence deceased donor kidney procurement biopsy reliability are not well established. We examined the impact of biopsy technique and pathologist training on procurement biopsy accuracy.

Methods

We retrospectively identified all deceased donor kidney-only transplants at our center from 2006 to 2016 with both procurement and reperfusion biopsies performed and information available on procurement biopsy technique and pathologist (n = 392). Biopsies were scored using a previously validated system, classifying “suboptimal” histology as the presence of at least 1 of the following: glomerulosclerosis ≥11%, moderate/severe interstitial fibrosis/tubular atrophy, or moderate/severe vascular disease. We calculated relative risk ratios (RRR) to determine the influence of technique (core vs. wedge) and pathologist (renal vs. nonrenal) on concordance between procurement and reperfusion biopsy histologic classification.

Results

A total of 171 (44%) procurement biopsies used wedge technique, and 221 (56%) used core technique. Results of only 36 biopsies (9%) were interpreted by renal pathologists. Correlation between procurement and reperfusion glomerulosclerosis was poor for both wedge (r² = 0.11) and core (r² = 0.14) biopsies. Overall, 34% of kidneys had discordant classification on procurement versus reperfusion biopsy. Neither biopsy technique nor pathologist training was associated with concordance between procurement and reperfusion histology, but a larger number of sampled glomeruli was associated with a higher likelihood of concordance (adjusted RRR = 1.12 per 10 glomeruli, 95% confidence interval = 1.04−1.22).

Conclusions

Biopsy technique and pathologist training were not associated with procurement biopsy histologic accuracy in this retrospective study. Prospective trials are needed to determine how to optimize procurement biopsy practices.

Digital pathology for second opinion consultation and donor assessment during organ procurement: Review of the literature and guidance for deployment in transplant practice

Telepathology has been an important application for second opinion consultation ever since the introduction of digital pathology. However, little is known regarding teleconsultation for second opinion in transplantation. There is also limited literature on telepathology during organ donor procurement, typically utilized when general pathologists on-call request back-up to help assess donor biopsies for organ suitability or to diagnose newly discovered tumors with urgent time constraints. In this review, we searched Pubmed/Embase and websites of transplant organizations to collect and analyze published evidence on teleconsultation for donor evaluation and organ procurement. Of 2725 records retrieved using the key terms 'telepathology', 'second opinion' and 'transplantation', 26 suitable studies were included. Most records were from North America and included validation studies of telepathology being used for remote frozen section interpretation of donor biopsies with whole slide imaging. The data from these published studies supports the transition towards digital teleconsultation in transplant settings where consultations among pathologists are still handled by pathologists being called on site, via telephone and/or email.

We listed patients and we should transplant them

Twenty percent of kidneys recovered for transplantation are discarded. The most common reason for not transplanting these kidneys is to organ quality and biopsy findings. Yet, organ quality measures are not associated with discard rates and kidneys with poorer quality measures lead to greater life span for the recipient compared to staying on dialysis. Biopsy findings are not correlated with graft survival in most cases. The risk aversion of transplant centers from using "high-risk" kidneys can be, in part at least, attributed to negative consequences of poor graft survival with possible program sanctions or possible loss of insurance contracts. CMS has taken a first step by eliminating short-term graft survival as a performance measure for transplant centers. Many of the discarded kidneys will provide good results if transplanted and would recognize that patients value getting a transplant above graft survival.