A Survey of United States Transplant Center Donation After Circulatory Death Kidney Transplant Practices in the Modern Era

BACKGROUND

The mismatch between the number of patients awaiting kidney transplantation and the supply of donor organs has contributed to the increase in kidney transplantation from donors after circulatory death (DCD). Persistently long waiting times have led the transplant community to continue to explore the use of expanded- criteria DCD kidneys. In parallel, advances in organ preservation strategies have contributed to an overall increase in DCD organ transplantation and are altering the transplant landscape. Some of these techniques may improve kidney allograft outcomes and affect how DCD kidneys are used. We aimed to better understand practices in accepting DCD kidney offers in the modern era.

METHODS

Directors of 196 US kidney transplant centers were emailed a link to an online survey over a 5-week period.

RESULTS

Forty-eight out of the 364 directors (13%) responded, with all United Network for Organ Sharing regions represented. Definitions of warm ischemia time (WIT) used in DCD kidney evaluation varied widely among the respondents. The maximum total WIT limit varied, with 19 (39.6%) <60-minute responses, followed by 16 (33%) <90-minute responses, and 10 (20.8%) <120-minute responses.

CONCLUSIONS

Despite increasing DCD kidney transplantation volumes in the United States, there are no standardized procurement biopsy practices, organ procurement organization preoperative protocols, or consensus definition or limits of WIT. Agreement on terminology may facilitate rapid clinical communication, efficiency of organ allocation and utilization, recording of data, research, and improvements in policy.

Ten Years of Quality Monitoring of Abdominal Organ Procurement in the Netherlands and Its Impact on Transplant Outcome

In this study, 10 years of procurement quality monitoring data were analyzed to identify potential risk factors associated with procurement-related injury and their association with long-term graft survival. All deceased kidney, liver, and pancreas donors from 2012 to 2022 and their corresponding recipients in the Netherlands were retrospectively included. The incidence of procurement-related injuries and potential risk factors were analyzed. Of all abdominal organs procured, 23% exhibited procurement-related injuries, with a discard rate of 4.0%. In kidneys and livers, 23% of the grafts had procurement-related injury, with 2.5% and 4% of organs with procurement-related injury being discarded, respectively. In pancreas procurement, this was 27%, with a discard rate of 24%. Male donor gender and donor BMI >25 were significant risk factors for procurement-related injury in all three abdominal organs, whereas aberrant vascularization was significant only for the kidney and liver. In the multivariable Cox regression analyses, procurement-related injury was not a significant predictor for graft failure (kidney; HR 0.99, 95% CI 0.75-1.33, p = 0.99, liver; HR 0.92, 95% CI 0.66-1.28, p = 0.61, pancreas: HR 1.16; 95% CI 0.16-8.68, p = 0.88). The findings of this study suggest that transplant surgeons exhibited good decision-making skills in determining the acceptability and repairability of procurement-related injuries.

Impact of Extraction Time During Donation After Circulatory Death Organ Procurement on Kidney Function After Transplantation in The Netherlands

Background

In The Netherlands, 60% of deceased-donor kidney offers are after donation after circulatory death. Cold and warm ischemia times are known risk factors for delayed graft function (DGF) and inferior allograft survival. Extraction time is a relatively new ischemia time. During procurement, cooling of the kidneys is suboptimal with ongoing ischemia. However, evidence is lacking on whether extraction time has an impact on DGF if all ischemic periods are included.

Methods

Between 2012 and 2018, 1524 donation after circulatory death kidneys were procured and transplanted in The Netherlands. Donation and transplantation-related data were obtained from the database of the Dutch Transplant Foundation. The primary outcome parameter was the incidence of DGF.

Results

In our cohort, extraction time ranged from 14 to 237 min, with a mean of 62 min (SD 32). In multivariate logistic regression analysis, extraction time was an independent risk factor for incidence of DGF (odds ratio per minute increase 1.008; 95% confidence interval, 1.003-1.013; P = 0.001). The agonal phase, hypoperfusion time, and anastomosis time were not independent risk factors for incidence of DGF.

Conclusions

Considering all known ischemic periods during the donation after the circulatory death process, prolonged kidney extraction time increased the risk of DGF after kidney transplantation.

The Effect of Recipient Back-Table Duration on Graft Outcome of Deceased Donor Kidneys: A Single-Center Prospective Cohort Study

Background: Little is known about the influence of the duration of the kidney back-table preparation period and kidney temperature on graft outcomes after transplantation. The aim of this study is to investigate the back-table duration and its relation to graft outcome and the relation between kidney temperature and graft outcome. Methods: In this prospective cohort study, deceased donor kidney temperature is measured at fixed time points using an infrared thermometer during back-table preparation and transplantation. Additionally, the back-table duration is measured using a timer. Results: Between September 2020 and July 2021, 49 kidneys were prospectively included in this study. Median back-table duration was 33.7 (standard deviation ± 14.1) min and donor kidney temperature increased up to 14.9 °C (±2.8) after 60 min of back-table preparation. Mean implantation time was 24.9 (±7.6) min and kidney temperature increased up to 25.9 °C (±2.4) after 30 min of implantation time. Longer back-table duration was significantly associated with higher rates of delayed graft function (p = 0.037). However, this observation did not sustain at 3 and 6-months post-transplantation. No association was found between kidney temperature and graft outcomes. Conclusion: Longer back-table duration is significantly associated with DGF after deceased donor kidney transplantation. No association was observed between kidney temperature and graft outcomes of deceased donor kidneys.

Simultaneous thoracic and abdominal donation after circulatory death organ recovery: the abdominal surgeon's perspective

PURPOSE OF THE REVIEW

To summarize the international experience with heart-liver (joint) donation after circulatory death (DCD) procurements and to explore the technical challenges in joint abdominal and thoracic DCD procurement.

RECENT FINDINGS

Following completion of the Donors After Circulatory Death Heart Trial in the US, combined thoracic and abdominal DCD is poised to become the standard of care, expanding access to life-saving heart and lung allografts. DCD heart procurement relies on collection of donor blood for priming of the normothermic perfusion pump, which delays cooling of abdominal organs and increases risk of ischemic injury. We review the effect of donor ischemia time on abdominal organs, with several proposed technical solutions to optimize transplant outcomes for all organs.

SUMMARY

The strategies reviewed in this manuscript may inform clinical decision-making, preoperative coordination between thoracic and abdominal procurement teams, and surgical technique for joint DCD procurements. Several approaches to organ procurement organization (OPO) and national policy, as well as future areas of focus for research are proposed.

H2S-Enriched Flush out Does Not Increase Donor Organ Quality in a Porcine Kidney Perfusion Model

Kidney extraction time has a detrimental effect on post-transplantation outcome. This study aims to improve the flush-out and potentially decrease ischemic injury by the addition of hydrogen sulphide (H2S) to the flush medium. Porcine kidneys (n = 22) were extracted during organ recovery surgery. Pigs underwent brain death induction or a Sham operation, resulting in four groups: donation after brain death (DBD) control, DBD H2S, non-DBD control, and non-DBD H2S. Directly after the abdominal flush, kidneys were extracted and flushed with or without H2S and stored for 13 h via static cold storage (SCS) +/− H2S before reperfusion on normothermic machine perfusion. Pro-inflammatory cytokines IL-1b and IL-8 were significantly lower in H2S treated DBD kidneys during NMP (p = 0.03). The non-DBD kidneys show superiority in renal function (creatinine clearance and FENa) compared to the DBD control group (p = 0.03 and p = 0.004). No differences were seen in perfusion parameters, injury markers and histological appearance. We found an overall trend of better renal function in the non-DBD kidneys compared to the DBD kidneys. The addition of H2S during the flush out and SCS resulted in a reduction in pro-inflammatory cytokines without affecting renal function or injury markers.

American Society of Transplant Surgeons recommendations on best practices in donation after circulatory death organ procurement

The American Society of Transplant Surgeons supports efforts to increase the number of organs that are critically needed for patients desperately awaiting transplantation. In the United States, transplantation using organs procured from donation after circulatory death (DCD) donors has continued to increase in number. Despite these increases, substantial variability in the utilization and practices of DCD transplantation still exists. To improve DCD organ utilization, it is important to create a set of best practices for DCD recovery. The following recommendations aim to provide guidance on contemporary issues surrounding DCD organ procurement in the United States. A work group was composed of members of the American Society of Transplant Surgeon Scientific Studies Committee and the Thoracic Organ Transplantation Committee. The following topics were identified by the group either as controversial or lacking standardization: prewithdrawal preparation, definition of donor warm ischemia time, DCD surgical technique, combined thoracic and abdominal procurements, and normothermic regional perfusion. The proposed recommendations were classified on the basis of the grade of available evidence and the strength of the recommendation. This information should be valuable for transplant programs as well as for organ procurement organizations and donor hospitals as they develop robust DCD donor procurement protocols.

Effect of donor pancreas extraction time on pancreas transplantation-a Swiss tertiary center experience

We aimed to assess the effect of donor pancreas extraction time (ET) on postoperative complications and graft function after pancreas transplantation (PT). We analyzed all consecutive donor pancreas procurements for the simultaneous pancreas and kidney transplantation (SPK) and the associated PT in a Swiss transplant center over a 20-year period. Pancreas ET was defined as the time from cold flush to static storage of the pancreas on ice. The primary endpoint was the effect of extraction time on surgical complications. Secondary endpoints comprised the effect of ET on graft function (insulin-free survival) and graft pancreatitis. Of 115 procured pancreas grafts the median donor pancreas ET was 65 min (IQR: 48-78 min). In multivariable analysis, ET did not negatively affect major complications (OR 1.41 [95% CI: .59-3.36]; p = .438) and insulin-free survival (HR 1.42 [95% CI: .55-3.63]; p = .459). The median CIT was 522 (441-608) min. CIT was associated with major complications (OR 2.51 [95% CI: 1.11-5.68]; p = .027), but without impact on insulin-free survival (HR 1.94 [95% CI: .84-4.48]; p = .119). Patients with and without graft pancreatitis had no statistically significant differences in ET and CIT (p = .164 and p = .47, respectively). In multivariable analysis, Amylase levels > 270 U/L on postoperative day 1 were significantly associated with major complications (OR 3.61 [95% CI: 1.06-12.32]; p = .040). Our results suggest that although no effect of ET on complications and graft function after PT was found, shorter CIT and less graft pancreatitis can have a positive impact on surgical complications. Results could possibly be influenced by the exceptional quality of the pancreas donors, with short travel distances and preservation times in Switzerland.

Insulating jackets thermally protect kidneys in an ex vivo model of second warm ischemia

BACKGROUND

Kidney transplantation is the current optimal treatment for suitable patients with end-stage renal disease. The second warm ischemic time (SWIT) is known to negatively impact delayed graft function, and long-term graft survival, and methods are required to ameliorate the impacts of SWIT on transplantation outcomes.

MATERIALS AND METHODS

This study primarily focused on determining the effect of a novel thermally insulating jacket on the thermal profile of the human kidney and quantifying the reduction in thermal energy experienced using this device (KPJ™). An ex vivo simulated transplantation model was developed to determine the thermal profiles of non-utilized human kidneys with and without KPJ™ (n = 5). Control kidney temperature profiles were validated against the temperature profiles of n = 10 kidneys during clinical kidney transplantation.

RESULTS

Using the ex-vivo water bath model, the thermally insulated human kidney reached the 15°C metabolic threshold temperature at 44.5 ± 1.9 min (vs control: 17.3 ± 1.8 min (p = 0.00172)) and remained within the 18°C threshold until 53.3 ± 1.3 min (vs control: 20.9 ± 2.0 min (p = 0.002)). The specific heat capacity of KPJ™ protected kidney was four-fold compared to the control kidney. The clinical temperature audit, closely correlated with the water bath model, hence validating this ex-vivo human kidney transplant model.

CONCLUSION

Intraoperative thermal protection is a simple and viable method of reducing the thermal injury that occurs during the SWIT and increasing the specific heat capacity of the system. Such technology could easily be translated into clinical kidney transplant practice.

Anastomosis Time and Outcomes after Donation after Circulatory Death Kidney Transplantation

BACKGROUND

At every stage in the transplantation process for a deceased-donor kidney, time means ischemia. Donation after circulatory death (DCD) kidneys are already subject to warm ischemia in the donor, but another underappreciated component of warm ischemia time is the time required for anastomosis prior to reperfusion. We studied the effect of anastomosis time (AT) on outcomes after DCD kidney transplantation.

STUDY DESIGN

This is a retrospective study of the Scientific Registry of Transplant Recipients, including all US adult DCD kidney transplantation recipients from 2009 to 2015 (N = 6,397). Our exposure was AT (time out of cold storage until reperfusion, quartiles). Outcomes included delayed graft function (DGF), death-censored graft survival, and overall patient survival. Multivariable logistic and Cox regression quantified the association of AT with outcomes, adjusting for donor and recipient factors (including donor warm ischemia time).

RESULTS

AT accounted for 67% of total warm ischemia time on average, with a median AT of 38 minutes (median total warm ischemia 56 minutes). Longer AT (fourth [≥48min] vs first quartile [≤30min]) was associated with increased DGF (odds ratio = 1.19, p = 0.024) and increased graft failure (hazard ratio = 1.21, p = 0.043) but was not associated with patient survival. Comparing patients with the longest vs shortest AT, adjusted DGF incidence was 44.0% vs 36.7% (p = 0.024), and 5-year graft survival was 84.8% vs 88.2% (p = 0.004).

CONCLUSION

Prolonged AT is associated with worse graft outcomes in DCD kidney transplant recipients. Efforts to minimize rewarming during implantation and optimize AT may improve graft outcomes.

Prolonged Organ Extraction Time Negatively Impacts Kidney Transplantation Outcome

Main Problem: Following cold aortic flush in a deceased organ donation procedure, kidneys never reach the intended 0–4°C and stay ischemic at around 20°C in the donor’s body until actual surgical retrieval. Therefore, organ extraction time could have a detrimental influence on kidney transplant outcome.

Materials and Methods: We analyzed the association between extraction time and kidney transplant outcome in multicenter data of 5,426 transplant procedures from the Dutch Organ Transplantation Registry (NOTR) and 15,849 transplant procedures from the United Network for Organ Sharing (UNOS).

Results: Extraction time was grouped per 10-min increment. In the NOTR database, extraction time was independently associated with graft loss [HR 1.027 (1.004–1.050); p = 0.022] and with DGF [OR 1.043 (1.021–1.066); p < 0.005]. An extraction time >80 min was associated with a 27.4% higher hazard rate of graft failure [HR 1.274 (1.080–1.502); p = 0.004] and such kidneys had 43.8% higher odds of developing DGF [OR 1.438, (1.236–1.673); p < 0.005]. In the UNOS database, increasing extraction times in DCD donors were associated with DGF [OR 1.036 (1.016–1.055); p < 0.005]. An extraction time >30 min was associated with 14.5% higher odds of developing DGF [OR 1.145 (1.063–1.233); p < 0.005].

Discussion: Prolonged kidney extraction time negatively influenced graft survival in Dutch donors and increased DGF risk in all deceased donor recipients.

Comparing outcomes in right versus left kidney transplantation: A systematic review and meta-analysis

INTRODUCTION

Transplantation of right kidneys can pose technical challenges due to the short right renal vein. Whether this results in inferior outcomes remains controversial.

METHOD

Healthcare Database Advanced Search (HDAS) was used to identify relevant studies. Two authors independently reviewed each study. Statistical analyses were performed using random effects models and results expressed as HR or relative risk (RR) with 95% confidence intervals. Subgroup analyses were performed in kidneys from deceased donors (DD) and living donors (LD).

RESULTS

A total of 35 studies (257,429 participants) were identified. Both deceased and living donor right kidneys were at increased risk of delayed graft function (DGF; RR = 1.12[1.06-1.18] and RR = 1.33[1.21-1.46] respectively; both p < .0001). In absolute terms, for each 100 kidney pairs of DD kidneys transplanted there are 2.72 (1.67-3.78, p < .00001) excess episodes of DGF in right kidneys. Graft thromboses and graft loss due to technical failure was also significantly more likely in right kidneys, in both DD and LD settings. There was no evidence that laterality alters long term graft survival in LD or DD.

CONCLUSION

Right kidneys have inferior early outcomes, with higher rates of DGF, technical failure and graft thrombosis. However, these differences are small in absolute terms, and long-term graft survival is equivalent.

"Time is tissue"-A minireview on the importance of donor nephrectomy, donor hepatectomy, and implantation times in kidney and liver transplantation

Donor organs are exposed to sequential temperature changes during the transplantation process. The role of donor warm ischemia and cold ischemia times on post-transplant outcomes has been extensively studied. Much less attention has been paid to the transient ischemia occurring during donor organ removal and implantation. Recently, it has become clear that prolonged donor nephrectomy and implantation time are independently associated with delayed graft function after kidney transplantation. In addition, implantation time correlates with post-transplant kidney graft function, histology, and survival. Similar detrimental associations of donor hepatectomy and implantation time with early allograft dysfunction, ischemic cholangiopathy, and graft and patient survival after liver transplantation have been demonstrated. This review details kidney and liver temperature changes occurring during procurement and transplantation. It summarizes the effects of the ischemia the kidney and liver sustain during these phases on short- and long-term post-transplant outcomes, advocating the standardized reporting of donor hepatectomy, donor nephrectomy, and implantation times in (inter)national registries. The review also explores strategies to protect the graft from this ischemic injury.

The impact of donor pancreas extraction time on graft survival and postoperative complications in pancreas transplant recipients

BACKGROUND

Simultaneous pancreas kidney transplantation (SPK) is the best therapeutic option for patients with diabetes mellitus type 1 and end-stage renal disease. Recently, donor organ extraction time has been shown to affect kidney and liver graft survival. This study aimed to assess the effect of pancreas donor extraction time on graft survival and postoperative complications.

METHODS

We retrospectively analyzed all pancreas transplants performed in two Eurotransplant centers. The association of pancreas extraction time with pancreas graft survival was analyzed by a Cox proportional hazards regression analysis after 3 months, 1 and 5 year. Besides, the effect of pancreas extraction time on the incidence of severe postoperative complications was analyzed.

RESULTS

A total of 317 pancreas transplants were included in this study. Death-censored pancreas graft survival was 85.7% after one year and 76.7% after five years. Median pancreas donor extraction time was 64 min [IQR: 52-79 min]. After adjustment for potential confounders, death censored graft survival after 30 days (HR 1.01, 95% CI 0.9-1.03 (p = 0.23), 1 year (HR 1.01, 95% CI 0.99-1.03 (p = 0.22) and 5 years (HR 1.00, 95% CI 0.99-1.02 (p = 0.57) was not associated with pancreas donor extraction time. However, extraction time was significantly associated with a higher incidence of Clavien-Dindo ≥3 complications compared to Clavien-Dindo 1 + 2 complications: OR 1.012, 95% CI 1.00-1.02 (p = 0.039).

CONCLUSIONS

Our findings suggest that although no effect on graft survival was found, limiting pancreas extraction time can have a significant impact on lowering postoperative complications.