A Propensity Score-weighted Comparison of Outcomes Between Living and Standard Criteria Deceased Donor Kidney Transplant Recipients

Unlocking Rural Live-Kidney Donation Through Insights From a Decade-Long Analysis at a Single Center in the Northern Great Plains

BACKGROUND

Data on barriers to live-kidney donation in the rural United States is limited despite its widespread adoption across the country.

METHODS

A retrospective review of 1776 self-referrals for live-kidney donation between June 1, 2012, and May 31, 2022, was conducted. Multivariate analyses evaluated independent factors which may have potentially influenced donation at different stages in its process.

RESULTS

Of the 1776 self-referrals, 398 (22.4%) individuals underwent evaluation and 121 (6.8%) of those became live-kidney donors. Middle-aged people (average age = 43 years), Whites (91.7%), and women (70.2%) were the most likely to donate. One thousand, one hundred, eighteen individuals (63.0%) dropped out after completing the intake form and the primary reasons included lost to follow-up (32.1%) and donor retraction (24.6%). Concerns related to personal health and compatibility were the predominant subjective factors for retraction. Following in-person evaluation, the most common reasons were medical comorbidities (34.9%) and inoperable renal anatomy (26.5%). Of the 1655 people that did not donate, 178 (10.8%) individuals discovered a new diagnosis during their evaluation process.

CONCLUSIONS

Only a fraction of those who begin the process proceed to donate a kidney, and most withdraw voluntarily before reaching the in-person evaluation phase. Focused approaches aimed at concerns regarding personal health and donor-recipient compatibility in otherwise healthy, motivated candidates in the early phases of donation hold potential for improving retention rates and subsequent donations.

Outcomes of kidneys used for transplantation: an analysis of survival and function

Introduction

Kidney transplant recipients expect to survive the procedure with sufficient renal function for reliable dialysis freedom.

Methods

Transplant outcomes (survival and estimated renal function) were assessed after live and deceased donor transplantation from the US national database. Outcomes were stratified by age (donor and recipient) and donor type.

Results

Aggregate recipient outcomes were better transplanting living vs deceased donated kidneys. However, when stratified by the one-year renal function (within KDIGO CKD stage stratifications), surviving recipients had clinically similar dialysis-freedom, irrespective of donor type or age. The major outcome differences for recipients of age-stratified live and deceased kidneys was 1) the increasing frequency of one-year graft failures and 2) the increasing likelihood of severely limited renal function (CKD 4/5) with advancing donor age. Over 30% of recipients of deceased kidneys >65 years had either one-year graft failure or severely limited renal function contrasted to less than 15% of recipients of live kidneys aged >65 years.

Conclusions

Evolving techniques to reduce adverse events after urgent vs elective procedures, plus improved transplant outcome predictability with increased-age deceased donor kidneys using advanced predictive analytics (using age-stratified live kidney transplantation outcomes as a relevant reference point) should facilitate similar kidney transplant outcomes, irrespective of donor type.

Study of the predictive factors affecting outcomes of patients undergoing transperitoneal laparoscopic donor nephrectomy

PURPOSE

We aim to study the preoperative and intraoperative factors and compare against specific outcomes in patients undergoing transperitoneal laparoscopic donor nephrectomy and see if we could find what were the predictive factors for these outcomes.

METHODS

This is a prospective cohort study done in a single high-volume transplant center. 153 kidney donors were evaluated over a period of 1 year. The preoperative factors such as age, gender, smoking status, obesity, visceral obesity, perinephric fat thickness, number of vessels, anatomic abnormalities, comorbidities, and side of kidney and intraoperative factors such as lay of colon on the kidney, height of splenic or hepatic flexure of colon, loaded or unloaded colon, and sticky mesenteric fat were compared against specific outcomes such as duration of surgery, duration of hospital stay, postoperative paralytic ileus, and postoperative wound complications.

RESULTS

Multivariate logistic regression models were used to study the variables of interest against the various outcomes. There were three positive risk factors for increased hospital stay, which were perinephric fat thickness and height of splenic or hepatic flexure of colon and smoking history. There was one positive risk factor for postoperative paralytic ileus which is lay of colon with relation to kidney and there was one positive risk factor for postoperative wound complication which was visceral fat area.

CONCLUSION

The predictive factors for adverse postoperative outcomes after transperitoneal laparoscopic donor nephrectomy were perinephric fat thickness, height of splenic or hepatic flexure, smoking status, lay or redundancy of colon with relation to kidney and visceral fat area.

Renal Vessel Extension With Cryopreserved Vascular Grafts: Overcoming Surgical Pitfalls in Living Donor Kidney Transplant

In LDKT, right kidneys and kidneys with anomalous vascularization are often deferred because of concerns on complications and vascular reconstructions. To date, only few reports have examined renal vessel extension with cryopreserved vascular grafts in LDKT. The aim of this study is to investigate the effect of renal vessel extension on short-term outcomes and ischemia times in LDKT. From 2012 to 2020, recipients of LDKT with renal vessels extension were compared with standard LDKT recipients. Subset analysis of rights grafts and grafts with anomalous vascularization, with or without renal vessel extension, was performed. Recipients of LDKT with (n = 54) and without (n = 91) vascular extension experienced similar hospital stays, surgical complications and DGF rates. For grafts with multiple vessels, renal vessel extension granted a faster implantation time (44±5 vs. 72±14 min), which resulted comparable to that of standard anatomy grafts. Right kidney grafts with vascular extension had a faster implantation time compared to right kidney grafts without vascular lengthening (43±5 vs. 58±9 min), and a comparable implantation time to left kidney grafts. Renal vessel extension with cryopreserved vascular grafts allows faster implantation time in right kidney grafts or grafts with anomalous vascularization, maintaining similar surgical and functional outcomes.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Propensity Score and Instrumental Variable Techniques in Observational Transplantation Studies: An Overview and Worked Example Relating to Pre-Transplant Cardiac Screening

Inferring causality from observational studies is difficult due to inherent differences in patient characteristics between treated and untreated groups. The randomised controlled trial is the gold standard study design as the random allocation of individuals to treatment and control arms should result in an equal distribution of known and unknown prognostic factors at baseline. However, it is not always ethically or practically possible to perform such a study in the field of transplantation. Propensity score and instrumental variable techniques have theoretical advantages over conventional multivariable regression methods and are increasingly being used within observational studies to reduce the risk of confounding bias. An understanding of these techniques is required to critically appraise the literature. We provide an overview of propensity score and instrumental variable techniques for transplant clinicians, describing their principles, assumptions, strengths, and weaknesses. We discuss the different patient populations included in analyses and how to interpret results. We illustrate these points using data from the Access to Transplant and Transplant Outcome Measures study examining the association between pre-transplant cardiac screening in kidney transplant recipients and post-transplant cardiac events.

Post-transplant outcomes in recipients of living donor kidneys and intended recipients of living donor kidneys

Background

Long-term kidney transplant survival at the population level is consistently favorable, but this survival varies widely at an individual level due to both recipient and donor factors. The distinct contribution of recipient and donor factors to individual post kidney transplant outcome remains unclear. Comparing outcomes in deceased donor (DD) recipients with potential but non-actualized living donors (DD1) to those recipients with actualized living donors (LD), and to DD recipients without potential living donors (DD0) may provide transplant candidates with more information about their own post-transplant prognosis.

Methods

We conducted an observational retrospective cohort study of kidney transplant candidates presenting to our centre for evaluation between 01/01/06 and 31/12/18, and who also received a transplant during that time. Patients were followed to 31/08/2019. Candidates were classified as DD0, DD1, or LD based on whether they had an identified living donor at the time of initial pre-transplant assessment, and if the donor actualized or not. Primary outcome was 5-year death-censored graft survival, adjusted for common pre- and post-transplant donor and recipient risk factors. Secondary outcomes analyzed included patient survival and graft function.

Results

There were 453 kidney transplant recipients (LD = 136, DD1 = 83, DD0 = 234) who received a transplant during the study period. DD0 and DD1 did not differ in key donor organ characteristics. The 5-year death censored graft survival of DD1 was similar to LD (p = 0.19). DD0 graft survival was inferior to LD (p = 0.005), but also trended inferior to DD1 (p = 0.052). By multivariate Cox regression analysis, LD demonstrated similar 5-year graft survival to DD1 (HR for graft loss 0.8 [95% CI 0.25–2.6], p = 0.72) but LD graft survival was superior to DD0 (HR 0.34 [0.16–0.72], p = 0.005). The 5-year patient survival in DD1 was similar to LD (p = 0.26) but was superior to DD0 (p = 0.01).

Conclusions

DD recipients with potential but non-actualized living donors exhibit similar mid-term graft and patient survival compared to LD recipients. Having an identified living donor at the time of pre-transplant assessment portends a favorable prognosis for the recipient.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02718-6.

The Mayo Adhesive Probability score can help predict intra- and postoperative complications in patients undergoing laparoscopic donor nephrectomy

PURPOSE

Living donor nephrectomy is a high-stake procedure involving healthy individuals, therefore every effort should be made to define each patient's individualized risk and improve potential donors' information. The aim of this study was to evaluate the interest of the Mayo adhesive probability (MAP) score, an imaging-based score initially designed to estimate the risk of adherent perinephric fat in partial nephrectomy, to predict intra- and postoperative complications of living donor nephrectomy.

MATERIALS AND METHODS

We retrospectively reviewed the imaging, clinical, and follow-up data of 452 kidney donors who underwent laparoscopic donor nephrectomy in two academic centers.

RESULTS

Imaging and follow-up data were available for 307 kidney donors, among which 44 (14%) had a high MAP score (≥ 3). Intraoperative difficulties were encountered in 50 patients (16%), including difficult dissection (n = 35) and bleeding (n = 17). Conversion to open surgery was required for 13 patients (4.2%). On multivariate analysis, a MAP score ≥ 3 was significantly associated with the risk of intraoperative difficulty [OR 14.12 (5.58-35.7), p < 0.001] or conversion to open surgery [OR 18.96 (3.42-105.14), p = 0.0042]. Postoperative complications were noted in 99 patients (32%), including 12 patients (3.9%) with Clavien-Dindo grade III-IV complications. On multivariate analysis, a high MAP score was also associated with the risk of postoperative complications [OR 2.55 (1.20-5.40), p = 0.01].

CONCLUSIONS

In this retrospective bicentric study, a high MAP score was associated with the risk of intra- and postoperative complications of laparoscopic donor nephrectomy. The MAP score appears of interest in the living donor evaluation process to help improve donors' information and outcomes.