US Liver Transplant Outcomes After Normothermic Regional Perfusion vs Standard Super Rapid Recovery

Importance

Normothermic regional perfusion (NRP) is an emerging recovery modality for transplantable allografts from controlled donation after circulatory death (cDCD) donors. In the US, only 11.4% of liver recipients who are transplanted from a deceased donor receive a cDCD liver. NRP has the potential to safely expand the US donor pool with improved transplant outcomes as compared with standard super rapid recovery (SRR).

Objective

To assess outcomes of US liver transplants using controlled donation after circulatory death livers recovered with normothermic regional perfusion vs standard super rapid recovery.

Design, Setting, and Participants

This was a retrospective, observational cohort study comparing liver transplant outcomes from cDCD donors recovered by NRP vs SRR. Outcomes of cDCD liver transplant from January 2017 to May 2023 were collated from 17 US transplant centers and included livers recovered by SRR and NRP (thoracoabdominal NRP [TA-NRP] and abdominal NRP [A-NRP]). Seven transplant centers used NRP, allowing for liver allografts to be transplanted at 17 centers; 10 centers imported livers recovered via NRP from other centers.

Exposures

cDCD livers were recovered by either NRP or SRR.

Main Outcomes and Measures

The primary outcome was ischemic cholangiopathy (IC). Secondary end points included primary nonfunction (PNF), early allograft dysfunction (EAD), biliary anastomotic strictures, posttransplant length of stay (LOS), and patient and graft survival.

Results

A total of 242 cDCD livers were included in this study: 136 recovered by SRR and 106 recovered by NRP (TA-NRP, 79 and A-NRP, 27). Median (IQR) NRP and SRR donor age was 30.5 (22-44) years and 36 (27-49) years, respectively. Median (IQR) posttransplant LOS was significantly shorter in the NRP cohort (7 [5-11] days vs 10 [7-16] days; P < .001). PNF occurred only in the SRR allografts group (n = 2). EAD was more common in the SRR cohort (123 of 136 [56.1%] vs 77 of 106 [36.4%]; P = .007). Biliary anastomotic strictures were increased 2.8-fold in SRR recipients (7 of 105 [6.7%] vs 30 of 134 [22.4%]; P = .001). Only SRR recipients had IC (0 vs 12 of 133 [9.0%]; P = .002); IC-free survival by Kaplan-Meier was significantly improved in NRP recipients. Patient and graft survival were comparable between cohorts.

Conclusion and Relevance

There was comparable patient and graft survival in liver transplant recipients of cDCD donors recovered by NRP vs SRR, with reduced rates of IC, biliary complications, and EAD in NRP recipients. The feasibility of A-NRP and TA-NRP implementation across multiple US transplant centers supports increasing adoption of NRP to improve organ use, access to transplant, and risk of wait-list mortality.

Single-center Outcomes After Liver Transplantation With SARS-CoV-2-Positive Donors: An Argument for Increased Utilization

Background

The COVID-19 pandemic has led to an increase in SARS-CoV-2-test positive potential organ donors. The benefits of life-saving liver transplantation (LT) must be balanced against the potential risk of donor-derived viral transmission. Although emerging evidence suggests that the use of COVID-19-positive donor organs may be safe, granular series thoroughly evaluating safety are still needed. Results of 29 consecutive LTs from COVID-19-positive donors at a single center are presented here.

Methods

A retrospective cohort study of LT recipients between April 2020 and December 2022 was conducted. Differences between recipients of COVID-19-positive (n = 29 total; 25 index, 4 redo) and COVID-19-negative (n = 472 total; 454 index, 18 redo) deceased donor liver grafts were compared.

Results

COVID-19-positive donors were significantly younger (P = 0.04) and had lower kidney donor profile indices (P = 0.04) than COVID-19-negative donors. Recipients of COVID-19-positive donor grafts were older (P = 0.04) but otherwise similar to recipients of negative donors. Donor SARS-CoV-2 infection status was not associated with a overall survival of recipients (hazard ratio, 1.11; 95% confidence interval, 0.24-5.04; P = 0.89). There were 3 deaths among recipients of liver grafts from COVID-19-positive donors. No death seemed virally mediated because there was no qualitative association with peri-LT antispike antibody titers, post-LT prophylaxis, or SARS-CoV-2 variants.

Conclusions

The utilization of liver grafts from COVID-19-positive donors was not associated with a decreased overall survival of recipients. There was no suggestion of viral transmission from donor to recipient. The results from this large single-center study suggest that COVID-19-positive donors may be used safely to expand the deceased donor pool.

Effect of a Hispanic outreach program on referral and liver transplantation volume at a single center

BACKGROUND

Although Hispanic patients have high rates of end-stage liver disease and liver cancer, for which liver transplantation (LT) offers the best long-term outcomes, they are less likely to receive LT. Studies of end-stage renal disease patients and kidney transplant candidates have shown that targeted, culturally relevant interventions can increase the likelihood of Hispanic patients receiving kidney transplant. However, similar interventions remain largely unstudied in potential LT candidates.

METHODS

Referrals to a single center in Texas with a large Hispanic patient population were compared before (01/2018-12/2019) and after (7/2021-6/2023) the implementation of a targeted outreach program. Patient progress toward LT, reasons for ineligibility, and differences in insurance were examined between the two eras.

RESULTS

A greater proportion of Hispanic patients were referred for LT after the implementation of the outreach program (23.2% vs 26.2%, p = 0.004). Comparing the pre-outreach era to the post-outreach era, more Hispanic patients achieved waitlisting status (61 vs 78, respectively) and received a LT (971 vs 82, respectively). However, the proportion of Hispanic patients undergoing LT dropped from 30.2% to 20.3%. In the post-outreach era, half of the Hispanic patients were unable to get LT for financial reasons (112, 50.5%).

CONCLUSIONS

A targeted outreach program for Hispanic patients with end-stage liver disease effectively increased the total number of Hispanic LT referrals and recipients. However, many of the patients who were referred were ineligible for LT, most frequently for financial reasons. These results highlight the need for additional research into the most effective ways to ameliorate financial barriers to LT in this high-need community.

Bloodstream infections after solid organ transplantation: clinical epidemiology and antimicrobial resistance (2016-21)

Background

Solid organ transplant (SOT) recipients are at risk of bloodstream infections (BSIs) with MDR organisms (MDROs).

Objectives

To describe the epidemiology of BSI in the year after several types of SOT, as well as the prevalence of MDRO infections in this population.

Methods

We conducted a single-centre, retrospective study of kidney, liver, heart, and multi-organ transplantation patients. We examined BSIs ≤1 year from SOT and classified MDRO phenotypes for Staphylococcus aureus, enterococci, Enterobacterales, Pseudomonas aeruginosa and Candida spp. We compared BSI characteristics between SOT types and determined risk factors for 90 day mortality.

Results

We included 2293 patients [1251 (54.6%) kidney, 663 (28.9%) liver, 219 (9.6%) heart and 160 (7.0%) multi-organ transplant]. Overall, 8.5% of patients developed a BSI. BSIs were most common after multi-organ (23.1%) and liver (11.3%) transplantation (P < 0.001). Among 196 patients with BSI, 323 unique isolates were recovered, 147 (45.5%) of which were MDROs. MDROs were most common after liver transplant (53.4%). The most frequent MDROs were VRE (69.8% of enterococci) and ESBL-producing and carbapenem-resistant Enterobacterales (29.2% and 27.2% of Enterobacterales, respectively). Mortality after BSI was 9.7%; VRE was independently associated with mortality (adjusted OR 6.0, 95% CI 1.7-21.3).

Conclusions

BSI incidence after SOT was 8.5%, with a high proportion of MDROs (45.5%), especially after liver transplantation. These data, in conjunction with local antimicrobial resistance patterns and prescribing practices, may help guide empirical antimicrobial selection and stewardship practices after SOT.

Modern Outcomes After Liver Retransplantation: A Single-center Experience

BACKGROUND

The need for liver retransplantation (reLT) has increased proportionally with greater numbers of liver transplants (LTs) performed, use of marginal donors, degree of recipient preoperative liver dysfunction, and longer survival after LT. However, outcomes following reLT have been historically regarded as poor.

METHODS

To evaluate reLT in modern recipients, we retrospectively examined our single-center experience. Analysis included 1268 patients undergoing single LT and 68 patients undergoing reLT from January 2008 to December 2021.

RESULTS

Pre-LT mechanical ventilation, body mass index at LT, donor-recipient ABO incompatibility, early acute rejection, and length of hospitalization were associated with increased risk of needing reLT following index transplant. Overall and graft survival outcomes in the reLT cohort were equivalent to those after single LT. Mortality after reLT was associated with Kidney Donor Profile Index, national organ sharing at reLT, and LT donor death by anoxia and blood urea nitrogen levels. Survival after reLT was independent of the interval between initial LT and reLT, intraoperative packed red blood cell use, cold ischemia time, and preoperative mechanical ventilation, all previously linked to worse outcomes.

CONCLUSIONS

These data suggest that reLT is currently a safer option for patients with liver graft failure, with comparable outcomes to primary LT.

Revitalizing pancreas transplantation: creation of a hands-on training course for pancreas allograft procurement, backbench preparation, and transplantation

Despite a steady increase in the number of organs available for transplant in the United States, over the last two decades there has been a precipitous decrease in the annual number of pancreas transplants performed. One overlooked consequence of this decline in pancreas transplant volume has been a decrease in experience in proper pancreas procurement and transplantation techniques for transplant surgeons as well as fewer trained abdominal transplant fellows entering the workforce certified for pancreas procurement and transplantation, with those achieving certification having less-developed judgment, skills, and experience. To augment current fellowship training and provide a concentrated experience in pancreas procurement and transplantation, the ASTS developed a hands-on surgical skills workshop focused on proper techniques for pancreas allograft procurement and backbench preparation.

Progress in Combined Liver-lung Transplantation at a Single Center

Combined liver-lung transplantation is an uncommon, although vital, procedure for patients with simultaneous end-stage lung and liver disease. The utility of lung-liver transplant has been questioned because of initial poor survival outcomes, particularly when compared with liver-alone transplant recipients.

Methods

A single-center, retrospective review of the medical records of 19 adult lung-liver transplant recipients was conducted, comparing early recipients (2009-2014) with a recent cohort (2015-2021). Patients were also compared with the center's single lung or liver transplant recipients.

Results

Recent lung-liver recipients were older (P = 0.004), had a higher body mass index (P = 0.03), and were less likely to have ascites (P = 0.02), reflecting changes in the etiologies of lung and liver disease. Liver cold ischemia time was longer in the modern cohort (P = 0.004), and patients had a longer posttransplant length of hospitalization (P = 0.048). Overall survival was not statistically different between the 2 eras studied (P = 0.61), although 1-y survival was higher in the more recent group (90.9% versus 62.5%). Overall survival after lung-liver transplant was equivalent to lung-alone recipients and was significantly lower than liver-alone recipients (5-y survival: 52%, 51%, and 75%, respectively). Lung-liver recipient mortality was primarily driven by deaths within 6 mo of transplant due to infection and sepsis. Graft failure was not significantly different (liver: P = 0.06; lung: P = 0.74).

Conclusions

The severity of illness in lung-liver recipients combined with the infrequency of the procedure supports its continued use. However, particular attention should be paid to patient selection, immunosuppression, and prophylaxis against infection to ensure proper utilization of scarce donor organs.

Combined liver transplantation and sleeve gastrectomy: Report of a brief-interval staged approach

Pretransplantation bariatric surgery in patients with high Model for End-Stage Liver Disease (MELD) score is fraught with risks. Bariatric surgery after liver transplantation (LT) may be complicated by surgical adhesions but could have advantages if performed at the time of transplantation. We investigated a method of brief-interval staging combining LT and sleeve gastrectomy (SG). LT recipients with a body mass index (BMI) > 40 kg/m 2 received an SG during the same hospitalization as the LT (LT/SG), at the same time as a planned brief-interval return to the operating room for biliary anastomosis. Differences in intraoperative attributes of the LT (Stage 1) versus SG (Stage 2) procedures were analyzed using Wilcoxon signed-rank test with significance p  < 0.05 and compared with patients with obesity having a two-stage LT without SG. A total of 14 cases {median MELD score 33 (interquartile range [IQR], 18-40)} were compared with 28 controls; 60% were critically ill prior to surgery with mechanical ventilation, vasopressors, or continuous renal replacement therapy. Median interval between procedures was 16.1 (IQR, 12.5-22.7) hours for cases and 12.2 (IQR, 11.1-16.6) hours for controls, p  = 0.27. Median BMI at LT/SG was 47.0 (IQR, 41.7-51.3) kg/m 2 versus 38.1 (IQR, 35.7-39.8) kg/m 2 for controls, p  < 0.001. At 1 year, median excess body weight loss was 74.0% (IQR, 46.2%-78.7%) in cases and 15.8% (IQR, -5.4% to 62.6%) in controls, p  = 0.13; total weight loss was 38.1% (IQR, 23.9-42.9) in cases versus 7.7% (IQR, -2.4% to 27.6%) for controls, p  = 0.03. Graft survival at 1 year was 92.9% for cases and 89.3% for controls with similar early postoperative outcomes. This proof-of-concept study revealed that a brief-interval SG during LT is feasible in patients with high MELD and resulted in sustained weight loss at 1 year with similar graft survival. Further studies are needed to determine an optimal strategy.

Outcomes of a High-Volume Organ Procurement Organization in the Era of Increasing Donation After Circulatory Death

Introduction: Donation after circulatory death (DCD) is rapidly increasing in the United States. Detailed data outlining the process from referral to organ transplantation is lacking. Project Aims: We sought to quantify differences at each stage along the referral to donation pathway by donor type. Additionally, we examined factors associated with successful DCD organ utilization. Design: This program evaluation analyzed data from a single organ procurement organization in 2018 to assess demographic and clinical predictors of progression through the donation process, including the role of first-person authorization in DCD. Descriptive statistics were examined by donation stage for demographic characteristics using chi-square; univariate and multivariate logistic regression was used to model predictors of utilization and authorization by organ type, respectively. Results: There were 2466 organ donation referrals during 2018, including 575 donations after brainstem death (DBD), 1890 controlled DCD referrals, and 1 uncontrolled DCD referral. Univariate and multivariate logistic regression models highlighted differences in authorization rates by donor type (DCD vs DBD) and by age, race, and ethnicity. Next-of-kin authorization was declined in 23% of first-person authorized potential DCD, highlighting issues related to the role of donor registration in DCD. Pre-mortem heparin administration was predictive of DCD organ utilization; donor age and warm ischemia time of less than 30 min was statistically significantly associated with DCD extra-renal organ utilization. Conclusion: These results provided insight into strategies for increasing authorization and transplantation of organs from DCD donors and identified areas of improvement for process standardization and policy development.

Survival following liver transplantation for locally advanced, unresectable intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) has previously been considered a contraindication to liver transplantation (LT). However, recent series showed favorable outcomes for LT after neoadjuvant therapy. Our center developed a protocol for neoadjuvant therapy and LT for patients with locally advanced, unresectable iCCA in 2010. Patients undergoing LT were required to demonstrate disease stability for 6 months on neoadjuvant therapy with no extrahepatic disease. During the study period, 32 patients were listed for LT and 18 patients underwent LT. For transplanted patients, the median number of iCCA tumors was 2, and the median cumulative tumor diameter was 10.4 cm. Patients receiving LT had an overall survival at 1-, 3-, and 5-years of 100%, 71%, and 57%. Recurrences occurred in seven patients and were treated with systemic therapy and resection. The study population had a higher than expected proportion of patients with genetic alterations in fibroblast growth factor receptor (FGFR) and DNA damage repair pathways. These data support LT as a treatment for highly selected patients with locally advanced, unresectable iCCA. Further studies to identify criteria for LT in iCCA and factors predicting survival are warranted.

In silico deceased donor intervention research: A potential accelerant for progress

Progress in deceased donor intervention research has been limited. Development of an in silico model of deceased donor physiology may elucidate potential therapeutic targets and provide an efficient mechanism for testing proposed deceased donor interventions. In this study, we report a preliminary in silico model of deceased kidney donor injury built, calibrated, and validated based on data from published animal and human studies. We demonstrate that the in silico model behaves like animal studies of brain death pathophysiology with respect to upstream markers of renal injury including hemodynamics, oxygenation, cytokines expression, and inflammation. Therapeutic hypothermia, a deceased donor intervention studied in human trials, is performed to demonstrate the model's ability to mimic an established clinical trial. Finally, future directions for developing this concept into a functional, clinically applicable model are discussed.

Donation after circulatory death liver transplantation: An in-depth analysis and propensity score-matched comparison

BACKGROUND

Careful donor-recipient matching and reduced ischemia times have improved outcomes following donation after circulatory death (DCD) liver transplantation (LT). This study examines a single-center experience with DCD LT including high-acuity and hospitalized recipients.

METHODS

DCD LT outcomes were compared to a propensity score-matched (PSM) donation after brain death (DBD) LT cohort (1:4); 32 DCD LT patients and 128 PSM DBD LT patients transplanted from 2008 to 2018 were included. Analyses included Kaplan-Meier estimates and Cox proportional hazards models examining patient and graft survival.

RESULTS

Median MELD score in the DCD LT cohort was 22, with median MELD of 27 for DCD LT recipients with decompensated cirrhosis. No difference in mortality or graft loss was found (p < .05) between DCD LT and PSM DBD LT at 3 years post-transplant, nor was DCD an independent risk factor for patient or graft survival. Post-LT severe acute kidney injury was similar in both groups. Ischemic-type biliary lesions (ITBL) occurred in 6.3% (n = 2) of DCD LT recipients, resulting in 1 graft loss and 1 death.

CONCLUSION

This study supports that DCD LT outcomes can be similar to DBD LT, with a low rate of ITBL, in a cohort including high-acuity recipients. Strict donor selection criteria, ischemia time minimization, and avoiding futile donor/recipient combinations are essential considerations.

Delayed Implantation of Pumped Kidneys Decreases Renal Allograft Futility in Combined Liver-Kidney Transplantation

BACKGROUND

Combined liver-kidney transplantation (CLKT) improves survival for liver transplant recipients with renal dysfunction; however, the tenuous perioperative hemodynamic and metabolic milieu in high-acuity CLKT recipients increases delayed graft function and kidney allograft failure. We sought to analyze whether delayed KT through pumping would improve kidney outcomes following CLKT.

METHODS

A retrospective analysis (University of California Los Angeles [n = 145], Houston Methodist Hospital [n = 79]) was performed in all adults receiving CLKT at 2 high-volume transplant centers from February 2004 to January 2017, and recipients were analyzed for patient and allograft survival as well as renal outcomes following CLKT.

RESULTS

A total of 63 patients (28.1%) underwent delayed implantation of pumped kidneys during CLKT (dCLKT) and 161 patients (71.9%) received early implantation of nonpumped kidneys during CLKT (eCLKT). Most recipients were high-acuity with median biologic model of end-stage liver disease (MELD) score of, 35 for dCLKT and 34 for eCLKT (P = ns). Pretransplant, dCLKT had longer intensive care unit stay, were more often intubated, and had greater vasopressor use. Despite this, dCLKT exhibited improved 1-, 3-, and 5-year patient and kidney survival (P = 0.02) and decreased length of stay (P = 0.001), kidney allograft failure (P = 0.012), and dialysis duration (P = 0.031). This reduced kidney allograft futility (death or continued need for hemodialysis within 3 mo posttransplant) for dCLKT (6.3%) compared with eCLKT (19.9%) (P = 0.013).

CONCLUSIONS

Delayed implantation of pumped kidneys is associated with improved patient and renal allograft survival and decreased hospital length of stay despite longer kidney cold ischemia. These data should inform the ethical debate as to the futility of performing CLKT in high-acuity recipients.

Unexplained fever after pancreas transplantation

BACKGROUND

Fever occurs frequently early after pancreas transplant, however, the exact cause is often undetermined. Limited data are available on pancreas recipients experiencing unexplained, noninfectious fever. This study aims to characterize unexplained fever (UF) in pancreas recipients and its effect on patient and graft outcomes.

METHODS

We performed a retrospective cohort study of UF among consecutive pancreas or simultaneous pancreas-kidney transplant recipients from 1 January 2011 to 31 August 2015. Classification of UF was based on the absence of positive cultures, radiologic findings, and other diagnostic features of infection or rejection.

RESULTS

Twenty-three of 92 (25%) patients experienced UF. The UF episode first occurred at a mean of 31 ± 17 days post-transplant and accounted for 34 admissions with an average length of stay of 5.1 ± 3.4 days. Intravenous corticosteroid was administered following confirmation of negative diagnostic tests in 77% of patients, with fever resolution occurring in all. No differences were seen in rates of biopsy-proven rejection, graft loss, death, or documented infections compared to UF-free patients during the first-year post-transplant.

CONCLUSION

UF is a common cause for readmission following pancreas transplantation. While the etiology of UF remains difficult to identify, UF occurrence was not associated with adverse outcomes during the first-year post-transplant.

PROviding Better ACcess To ORgans: A comprehensive overview of organ-access initiatives from the ASTS PROACTOR Task Force

The American Society of Transplant Surgeons (ASTS) PROviding better Access To Organs (PROACTOR) Task Force was created to inform ongoing ASTS organ access efforts. Task force members were charged with comprehensively cataloguing current organ access activities and organizing them according to stakeholder type. This white paper summarizes the task force findings and makes recommendations for future ASTS organ access initiatives.

The New Kidney Donor Allocation System and Implications for Anesthesiologists

Given potential disparity and limited allocation of deceased donor kidneys for transplantation, a new federal kidney allocation system was implemented in 2014. Donor organ function and estimated recipient survival in this system has implications for perioperative management of kidney transplant recipients. Early analysis suggests that many of the anticipated goals are being attained. For anesthesiologists, implications of increased dialysis duration and burdens of end-stage renal disease include increased cardiopulmonary disease, challenging fluid, hemodynamic management, and central vein access. With no recent evidence to guide anesthesia care within this new system, we describe the kidney allocation system, summarize initial data, and briefly review organ systems of interest to anesthesiologists. As additional invasive and echocardiographic monitoring may be indicated, one consideration may be development of a dedicated anesthesiology team experienced in management and monitoring of complex patients, in a similar manner as has been done for liver transplant recipients.

Matrix metalloproteinases in peripheral vascular disease

Matrix metalloproteinases (MMPs) are extracellular matrix-modifying enzymes that are important in many physiologic and pathologic vascular processes. Dysregulation of MMP activity has been associated with common vascular diseases such as atherosclerotic plaque formation, abdominal aortic aneurysms, and critical limb ischemia. For this reason, MMPs have become an important focus for basic science studies and clinical investigations by vascular biology researchers. This article reviews the recent literature, summarizing our current understanding of the role of MMPs in the pathogenesis of various peripheral vascular disease states. In addition, the importance of MMPs in the future diagnosis and treatment of peripheral vascular disease is discussed.