Mathur, Amit K.

ABSTRACT Background With increasing use of donation after circulatory death (DCD) donor grafts, the need for accurate risk‐stratification tools in liver transplantation has become critical. Machine perfusion has been shown to improve both graft and patient survival. However, existing prediction models were developed in the static cold storage (SCS) era and their accuracy when using machine perfusion remains unknown. Our study aims to study if current scoring systems can predict graft and patient survival for DCD livers preserved using normothermic machine perfusion (NMP). Methods This was a retrospective study of patient and graft survival in a two‐center U.S. DCD NMP cohort ( n = 532) between January 2022 and December 2024. Predicted graft and patient survival rates were obtained from established risk scoring systems, including the United Kingdom DCD risk score (UK‐DCD), Early Allograft Dysfunction (EAD) Olthoff score, Liver Graft Assessment Following Transplantation (L‐GrAFT 7 ) score, Donor Risk Index (DRI), Balance of Risk (BAR) score, and Survival Outcomes Following Liver Transplant (SOFT) score. Model discrimination was assessed using receiver operating characteristic (ROC) curves (C‐statistics). Survival outcomes across risk strata were estimated and compared using Kaplan‐Meier (KM) analysis. Results Across scoring systems, predicted survival consistently underestimated actual graft and patient survival in the NMP DCD cohort. The DRI, SOFT, EAD and L‐GrAFT 7 did not demonstrate predictive value. UK‐DCD predicted ≤85% and <40% 1‐year graft survival for its high‐risk and “futile” groups, whereas observed rates were 93.7% and 86.8%. BAR low‐risk predicted >60% 5‐year survival but 94.2% was observed; the high‐risk group predicted <60% and observed was 53.3%. Despite underestimations and generally poor C‐statistics, in KM stratification, high‐risk groups still showed statistical differences in the UK‐DCD categories ( p = 0.007), and in SOFT score groups ( p < 0.001). No statistical difference was seen in BAR ( p = 0.36), DRI ( p = 0.36), EAD ( p = 0.12), or L‐GrAFT 7 ( p = 0.75). Conclusion Existing liver transplant risk scores show limited predictive value for donor‐related risk factors in the NMP era, whereas recipient‐related factors remain somewhat predictive, despite overestimating risk. Early allograft dysfunction metrics were not reliable predictors of short or long‐term outcomes. Future risk models should integrate machine‐perfusion parameters and refined donor variables to reflect outcomes more accurately in contemporary DCD liver transplantation.

ABSTRACT Despite the annual increase in liver transplants, a persistent disparity between suitable donors and recipients continues to challenge the transplant community. The introduction of machine perfusion emerged as a novel approach to organ preservation. This technique, which utilizes extended criteria donor grafts, is expected to reduce rejection rates and expand the donor pool. Its principle, like that of any ex vivo machine perfusion, is based on the continuous supply of nutrients and oxygen to maintain cellular metabolism while interrupting anaerobic processes. This helps prevent conditions such as ischemia-reperfusion injury, early graft dysfunction, and ischemic cholangiopathy, which can lead to graft loss and the need for retransplantation. There are two main modes of ex vivo machine perfusion: hypothermic and normothermic, differentiated by the operating temperature. Utilizing ex situ perfusion machines presents a promising opportunity to increase liver graft usage and reduce waitlist times. However, it is crucial to evaluate how much this technology would raise the overall cost of transplants. In Brazil, implementing a machine perfusion program may encounter unique challenges not seen in other countries. These challenges include limited access to the healthcare system for high-risk liver transplant candidates, long waiting lists, inadequate support for organ donors, reliance solely on deceased brain-dead donors, since donation after cardiac death is not ethically accepted, and geographical barriers.

Objective: To determine whether normothermic machine perfusion (NMP) mitigates the historical survival disadvantage of donation after circulatory death (DCD) liver transplantation compared with donation after brain death (DBD) livers. Summary Background Data: NMP has improved outcomes in DCD LT compared with static cold storage (SCS), but whether it eliminates the historical disparity relative to DBD transplantation remains uncertain. Methods: We performed a retrospective cohort study of adult LT at a high-volume US center between 2019 and 2024. Outcomes of DCD-NMP grafts were compared with DCD-SCS, DBD-SCS, and DBD-NMP grafts. Primary outcomes were 1-year graft and patient survival. Secondary outcomes included early allograft dysfunction (EAD), hepatic artery thrombosis (HAT), primary nonfunction (PNF), biliary anastomotic strictures (BAS), and ischemic cholangiopathy (IC). Results: Among 1338 liver transplants (DBD-SCS n=527; DBD-NMP n=142; DCD-SCS n=255; DCD-NMP n=414), DCD-NMP grafts had a significantly higher donor risk profile ( P <0.001) yet demonstrated survival comparable to DBD transplantation. One-year graft survival was 94% for DCD-NMP versus 93% for DBD grafts and 86% for DCD-SCS, and 1-year patient survival was 98% for DCD-NMP versus 94% to 95% for DBD grafts and 93% for DCD-SCS. In adjusted models, DCD-SCS was associated with increased hazards of graft loss (adjusted hazard ratio: 2.48; P <0.001) and death (adjusted hazard ratio: 2.39; P =0.004), whereas DBD groups did not differ from DCD-NMP. Incidence of EAD was lower with DCD-NMP (21.7%) than DCD-SCS (50.2%) and similar to DBD grafts (21.1%–26.4%); HAT and PNF were rare (≤1.3%). At 1 year, BAS occurred in 36% of DCD grafts versus 17% to 23% of DBD grafts. IC occurred in 7.7% of DCD-NMP compared with 22% of DCD-SCS and ≤1.5% of DBD grafts. Retransplantation due to IC was infrequent overall (1.3%), but more common in DCD-SCS (4.7%) than DCD-NMP (1.0%) and DBD grafts (≤0.4%). Conclusions: NMP enables safe utilization of DCD liver allografts and achieves graft and patient survival comparable to DBD LT, mitigating the historical disadvantage of DCD grafts. These findings support routine integration of NMP into clinical practice and efforts to standardize its implementation.

Purpose of review Living donor transplantation is the optimal treatment for end-stage renal disease and end-stage liver disease. For the recipient, the benefits of living donation include improved duration of graft survival compared to deceased donation and avoidance of lengthy waiting time and risks of dialysis. For transplant centers, a robust living donor program results in consistent transplant case volumes, daytime cases and a decreased reliance on potentially unfavorable allocation policy changes. Transplant programs require a playbook of actionable initiatives based on consensus best practices and peer-reviewed data to optimize opportunities to increase living donor evaluation and surgery within current legal and policy frameworks. Relevant findings Strategies to increase center living donor volume include utilization of culturally competent transplant education and outreach, development of living donor champion programs, wider utilization of financial assistance programs available to living donors, increased enrollment in paired donor exchange services and adaptation of modern evidence-based selection and evaluation criteria. Summary Understanding the current landscape of living donor transplantation and exploring areas of innovation is imperative to a center's ability to continue to serve the full spectrum of patients with end stage organ disease to the best of our collective ability.

Limited information on the business practices of liver transplant (LT) centers worldwide has been published. Characterizing this data could help identify best practices as well as opportunities for improvement. As such, the International Liver Transplant Society (ILTS) Business Practice Committee conducted a global online survey of LT centers, which was sent to the ILTS membership. Questions focused on 5 main domains: transplant practice and volumes, workforce, finances, quality assessment and performance improvement, and overall program function. Data was compared across program geographic regions and transplant volume. A total of 89 discrete centers were represented, of which 76.4% were academic/university-affiliated, and about one-third each were from Europe (36.0%) and North America (31.5%). The top 3 problems programs reported were finances/funding (60.7%), adequate program support/guidance (48.3%), and transplant volumes (43.8%). In all, 59.6% of respondents felt their salary was undercompensated, consistent across geographic regions. In addition, 69.7% felt their center was not adequately funded to meet program goals, with programs in Europe (N=28/32, 87.5%) and Oceania (N=2/3, 66.7%) most impacted. Transplant surgeon retainment was noted as more difficult for lower volume programs (<50 liver transplants/year, N=13/31). Nearly half (42.7%) of all programs felt under-resourced to provide high-quality care, and the majority (80.9%) felt there was room for growth and improvement under their current model. While international concerns varied widely among LT centers, inadequate salary and center funding, low transplant and referral volumes, and staff retainment were persistent themes. Focusing on adopting region-specific best practices and developing transplant systems of care that focus on these elements is critical to provide optimal care to LT patients worldwide.

Key Points Health care utilization rates in elderly kidney transplant were no different between the high kidney donor profile index and low kidney donor profile index group. Number of readmissions and surgical interventions in elderly kidney transplant was no different between the high kidney donor profile index and low kidney donor profile index group. Death censored graft loss was higher in the high kidney donor profile index group, whereas the patient survival was no different between the high kidney donor profile index and low kidney donor profile index groups. Background High kidney donor profile index (KDPI) kidneys (KDPI >85%) are often associated with increased risks of post-kidney transplant (KT) complications and greater health care utilization (HCU), particularly in elderly recipients with multiple comorbidities. These concerns frequently lead to underutilization of high KDPI kidneys in older transplant candidates, thereby limiting their access to transplantation despite potential clinical benefits. The aim of this study was to compare post-KT HCU between elderly recipients of high versus low KDPI deceased donor kidneys. The primary outcome included differences in hospital readmissions, surgical interventions, and outpatient service use at multiple post-transplant time points. Secondary outcome included graft function, graft survival, and patient survival. Methods A retrospective analysis of elderly solitary KT recipients (age ≥65 years) between January 1, 2011, and December 31, 2020. Patients were stratified into high KDPI (>85%, n =160) and low KDPI (≤85%, n =453) groups. We assessed inpatient and outpatient HCU, including readmissions at 30, 90, and 365 days post-transplant, surgical interventions, and outpatient visits (emergency department, transplant clinic, endocrine clinic, and ambulatory infusion units). Results There were no statistically significant differences between high and low KDPI groups in rates of hospital readmissions, surgical interventions, or outpatient visits (all P > 0.05). Delayed graft function rates were also similar ( P = 0.61). The low KDPI group had significantly higher eGFR at 4 months, 1, 2, and 3 years post-transplant (all P < 0.001). However, days alive and out of the hospital within 90 and 365 days post-transplant were comparable between the groups (all P > 0.05). Overall patient survival was similar ( P = 0.08), although death-censored graft loss was significantly higher in the high KDPI group ( P = 0.001). Conclusions Among elderly KT recipients, high KDPI kidney recipients had comparable post-transplant HCU and overall survival with those receiving low KDPI kidneys, despite lower long-term graft function. These findings suggest that high KDPI kidneys remain a viable option for older patients, offering timely access to transplantation.

Normothermic machine perfusion (NMP) enables preservation and functional assessment of liver allografts, improving outcomes, particularly in marginal organs. However, the TransMedics Organ Care System (OCS) permits only single hepatic artery (HA) cannulation, limiting its use in grafts with variant arterial anatomy. Arterial reconstruction before NMP may overcome this limitation and expand the pool of grafts eligible for perfusion. We conducted a retrospective single-center cohort study of adult liver transplants utilizing OCS from January 2022 to September 2024. Allografts with variant hepatic artery anatomy requiring arterial reconstruction before NMP initiation were identified. Postoperative outcomes, including vascular and biliary complications, were compared between reconstructed and non-reconstructed grafts. Among 541 OCS-preserved grafts, 74 (13.7%) underwent arterial reconstruction. Compared with non-reconstructed grafts, reconstructed grafts had longer cross-clamp to cannulation time (2.8 vs. 2.4 h, p <0.001), but similar rates of early allograft dysfunction (23.0% vs. 20.8%, p =0.65), ischemic cholangiopathy (4.1% vs. 4.1%, p =1.00), and primary nonfunction (0.0% vs. 0.4%, p =1.00). Early (2.7% vs. 0.2%, p =0.05) and late hepatic artery thrombosis (HAT) (4.1% vs. 2.1%, p =0.40) were infrequent and not significantly different between non-reconstructed and reconstructed groups, respectively. Hepatic artery stenosis occurred more often in reconstructed grafts (12.2% vs. 4.1%, p =0.008), though most cases were managed with interventional radiology or surgical revision. Only one reconstructed graft required retransplantation due to vascular complications. Arterial reconstruction before NMP is safe and feasible, enabling successful perfusion and transplantation of liver allografts with variant HA anatomy. These findings support the broader application of NMP in anatomically complex donor livers.

Background. Ex vivo machine perfusion (MP) has transformed organ preservation, offering significant benefits in liver transplantation (LT), particularly with high-risk donor grafts. However, adoption in the United States has been limited. We aimed to examine early adoption trends, surgeon perceptions, and barriers to implementing MP in the United States after Food and Drug Administration approval of MP platforms. Methods. A 23-question electronic survey was distributed to members of the American Society of Transplant Surgeons between October and November 2022, capturing attitudes and practices related to MP adoption. Responses from 96 surgeons representing 77 LT centers across 11 Organ Procurement and Transplantation Network regions were analyzed. Results. Forty-four respondents (48%) reported having an MP program at their institution. Adoption of MP was significantly more common in high-volume centers and those performing ≥20 donation after circulatory death (DCD) transplants annually (P < 0.001). MP utilization received strong support, with 88% endorsing its use for DCD liver allografts and 82% for donation after brain death allografts. Respondents cited MP’s ability to reduce ischemic cholangiopathy, enable graft repair, and facilitate viability assessment as key benefits. Normothermic MP was preferred for high-risk donor profiles, including DCD grafts, older donors, and steatotic livers, and was associated with an increased willingness to accept medically complex grafts compared with static cold storage. Barriers to MP utilization included program costs, personnel demands, and logistical complexities. Centers with higher proportions of privately insured patients were more likely to adopt MP. Despite these challenges, 84% of respondents expressed interest in future MP adoption. Conclusions. MP enhances graft utilization and outcomes, particularly for complex and high-risk donor livers, but widespread US adoption requires addressing financial and logistical barriers. Future efforts should focus on refining cost-effectiveness analyses, collaboration with organ procurement organizations and device companies, and developing standardized training to optimize MP integration and maximize its clinical impact on LT.