Pediatric Combined Heart-liver Transplantation: A Single-center Long-term Experience.

Background: Combined heart liver transplant (CHLT) continues to gain attention as a surgical treatment for patients with end-stage heart and liver disease but remains rare. We present our institutional longitudinal experience with up to 14 y of follow-up, focused on long-term outcomes in CHLT recipients. Methods: We conducted a single-institutional, retrospective review from January 1, 2010, to December 31, 2023, including 7 patients ages 7-17 y who underwent CHLT. Results: Most patients were surgically palliated via Fontan procedure pretransplant (n = 6), and all had evidence of advanced fibrosis or cirrhosis before transplant. The 30-d mortality was 14.3% (n = 1, multiorgan failure). During the follow-up period, 1 patient developed acute heart rejection which required treatment and 2 developed acute liver rejection. In all cases, rejection was successfully treated. Two patients developed acute heart rejection which did not require treatment (grade 1R). No patients developed chronic or refractory rejection. No patients developed allograft coronary artery vasculopathy. Conclusions: CHLT remains a rarely performed treatment for pediatric patients with end-stage heart and liver disease, but our long-term data suggest that this treatment strategy should be considered more frequently.

Heart-liver transplantation using the en bloc technique: A single-center experience over two decades.

BACKGROUND: Combined heart-liver transplantation (CHLT) is a definitive therapy reserved for patients with concomitant heart failure and advanced liver disease. A limited number of centers perform CHLT, and even fewer use the en bloc implantation technique. Here we review clinical outcomes and immunoprotective effects following CHLT and describe our institution's more than two decades of experience in performing the en bloc technique. METHODS: All patients who underwent CHLT at our institution between January 2003 and July 2023 were identified. Recipient and donor characteristics, operative details, and clinical outcomes were assessed. Kaplan-Meier analysis was performed to evaluate survival following CHLT. RESULTS: A total of 20 patients underwent CHLT using the en bloc technique at our institution between January 2003 and July 2023. At a median follow-up of 3.8 years for patients who survived the perioperative period (n = 18), estimated survival was 94% at 1 year and 75% at 5 years. There was 100% freedom from acute moderate rejection, acute severe rejection, and chronic rejection in all patients. No patients required retransplantation due to rejection. CONCLUSIONS: CHLT is a definitive therapy reserved for patients with multiorgan dysfunction. At our institution, the en bloc technique is the preferred operative approach, as it minimizes cardiac insult, requires fewer anastomoses, minimizes cold ischemia time, and allows for rapid correction of coagulopathy. Overall survival for this cohort is excellent. Episodes of acute rejection were rare, providing further support for the idea that the liver may serve an immunoprotective role in multiorgan transplantation.

Graft Survival of En Bloc Deceased Donor Kidneys Transplants Compared With Single Kidney Transplants.

BACKGROUND: The US Kidney Allocation System allocates en bloc deceased donor kidney grafts from donors <18 kg in sequence A along with single kidney transplants (SKTs) from kidney donor profile index (KDPI) top 20% donors. Although en bloc grafts outperform SKT grafts holding donor weight constant, it is unclear if en bloc grafts from the smallest pediatric donors perform the same as top 20% KDPI SKTs. METHODS: Using the Scientific Registry of Transplant Recipients, we compared the donor characteristics and graft survival of en bloc grafts from the smallest donors (<8 kg) and from larger donors (≥8 kg) with SKTs by KDPI sequence for transplants performed in 2021. RESULTS: Larger donor en blocs had similar 1-y survival to sequence A SKTs estimated by the Kaplan-Meier method (96% versus 96%, P = 0.9), but the smallest donor en blocs had significantly shorter 1-y survival than those SKTs (80% versus 96%, P < 0.01). Using transplants from 2010 to 2012, the smallest donor en blocs had similar 10-y survival to sequence A SKTs (69% versus 64%, P  = 0.3). CONCLUSIONS: These findings suggest that future updates of the Kidney Allocation System should include a score specific to pediatric donors to account for these differences in en bloc graft survival.

Technical Variant Liver Transplant Utilization for Pediatric Recipients: Equal Graft Survival to Whole Liver Transplants and Promotion of Timely Transplantation Only When Performed at High-volume Centers.

BACKGROUND: Technical variant liver transplantation (TVLT) is a strategy to mitigate persistent pediatric waitlist mortality in the United States, although its implementation remains stagnant. This study investigated the relationship between TVLT utilization, transplant center volume, and graft survival. METHODS: Pediatric liver transplant recipients from 2010 to 2020 (n = 5208) were analyzed using the Scientific Registry of Transplant Recipients database. Transplant centers were categorized according to the average number of pediatric liver transplants performed per year (high-volume, ≥5; low-volume, <5). Graft survival rates were compared using Kaplan-Meier curves and log-rank tests. Cox proportional hazards models were used to identify predictors of graft failure. RESULTS: High-volume centers demonstrated equivalent whole liver transplant and TVLT graft survival ( P = 0.057) and significantly improved TVLT graft survival compared with low-volume centers ( P < 0.001). Transplantation at a low-volume center was significantly associated with graft failure (adjusted hazard ratio, 1.6; 95% confidence interval, 1.14-2.24; P = 0.007 in patients <12 y old and 1.8; 95% confidence interval, 1.13-2.87; P = 0.013 in patients ≥12 y old). A subset of high-volume centers with a significantly higher rate of TVLT use demonstrated a 23% reduction in waitlist mortality. CONCLUSIONS: Prompt transplantation with increased TVLT utilization at high-volume centers may reduce pediatric waitlist mortality without compromising graft survival.

Alcohol Use in Liver Transplant Recipients With Alcohol-related Liver Disease: A Comparative Assessment of Relapse Prediction Models.

BACKGROUND: The selection of liver transplant (LT) candidates with alcohol-related liver disease (ALD) is influenced by the risk of alcohol relapse (AR), yet the ability to predict AR is limited. We evaluate psychosocial factors associated with post-LT AR and compare the performance of high-risk alcoholism risk (HRAR), sustained alcohol use post-LT (SALT), and the Stanford Integrated Psychosocial Assessment for Transplantation (SIPAT) scores in predicting relapse. METHODS: A retrospective analysis of ALD patients undergoing LT from 2015 to 2021 at a single US transplant center was performed. Risk factors associated with post-LT AR were evaluated and test characteristics of 3 prediction models were compared. RESULTS: Of 219 ALD LT recipients, 23 (11%) had AR during a median study follow-up of 37.5 mo. On multivariate analysis, comorbid psychiatric illness (odds ratio 5.22) and continued alcohol use after advice from a health care provider (odds ratio 3.8) were found to be significantly associated with post-LT AR. On sensitivity analysis, SIPAT of 30 was optimal on discriminating between ALD LT recipients with and without post-LT AR. SIPAT outperformed both the HRAR and SALT scores (c-statistic 0.67 versus 0.59 and 0.62, respectively) in identifying post-LT AR. However, all scores had poor positive predictive value (<25%). CONCLUSIONS: AR after LT is associated with comorbid psychiatric illness and lack of heeding health care provider advice to abstain from alcohol. Although SIPAT outperformed the HRAR and SALT scores in predicting AR, all are poor predictors. The current tools to predict post-LT AR should not be used to exclude LT candidacy.

The Accuracy of Nonstandardized MELD/PELD Score Exceptions in the Pediatric Liver Allocation System.

BACKGROUND: In the United States, over half of pediatric candidates receive exceptions and status upgrades that increase their allocation model of end-stage liver disease/pediatric end-stage liver disease (MELD/PELD) score above their laboratory MELD/PELD score. We determined whether these "nonstandardized" MELD/PELD exceptions accurately depict true pretransplant mortality risk. METHODS: Using data from the Scientific Registry of Transplant Recipients, we identified pediatric candidates (<18 y of age) with chronic liver failure added to the waitlist between June 2016 and September 2021 and estimated all-cause pretransplant mortality with mixed-effects Cox proportional hazards models that treated allocation MELD/PELD and exception status as time-dependent covariates. We also estimated concordance statistics comparing the performance of laboratory MELD/PELD with allocation MELD/PELD. We then compared the proportion of candidates with exceptions before and after the establishment of the National Liver Review Board. RESULTS: Out of 2026 pediatric candidates listed during our study period, 403 (19.9%) received an exception within a week of listing and 1182 (58.3%) received an exception before delisting. Candidates prioritized by their laboratory MELD/PELD scores had an almost 9 times greater risk of pretransplant mortality compared with candidates who received the same allocation score from an exception (hazard ratio 8.69; 95% confidence interval, 4.71-16.03; P < 0.001). The laboratory MELD/PELD score without exceptions was more accurate than the allocation MELD/PELD score with exceptions (Harrell's c-index 0.843 versus 0.763). The proportion of patients with an active exception at the time of transplant decreased significantly after the National Liver Review Board was implemented (67.4% versus 43.4%, P < 0.001). CONCLUSIONS: Nonstandardized exceptions undermine the rank ordering of pediatric candidates with chronic liver failure.

Complement-Binding Donor-Specific Anti-HLA Antibodies: Biomarker for Immunologic Risk Stratification in Pediatric Kidney Transplantation Recipients.

Antibody-mediated rejection is a common cause of early kidney allograft loss but the specifics of antibody measurement, therapies and endpoints have not been universally defined. In this retrospective study, we assessed the performance of risk stratification using systematic donor-specific antibody (DSA) monitoring. Included in the study were children who underwent kidney transplantation between January 1, 2010 and March 1, 2018 at Stanford, with at least 12-months follow-up. A total of 233 patients were included with a mean follow-up time of 45 (range, 9-108) months. Median age at transplant was 12.3 years, 46.8% were female, and 76% had a deceased donor transplant. Fifty-two (22%) formed C1q-binding de novo donor-specific antibodies (C1q-dnDSA). After a standardized augmented immunosuppressive protocol was implemented, C1q-dnDSA disappeared in 31 (58.5%). Graft failure occurred in 16 patients at a median of 54 (range, 5-83) months, of whom 14 formed dnDSA. The 14 patients who lost their graft due to rejection, all had persistent C1q-dnDSA. C1q-binding status improved the individual risk assessment, with persistent; C1q binding yielding the strongest independent association of graft failure (hazard ratio, 45.5; 95% confidence interval, 11.7-177.4). C1q-dnDSA is more useful than standard dnDSA as a noninvasive biomarker for identifying patients at the highest risk of graft failure.

Patterns in Tacrolimus Variability and Association with De Novo Donor-Specific Antibody Formation in Pediatric Kidney Transplant Recipients.

BACKGROUND AND OBJECTIVES: High tacrolimus intrapatient variability has been associated with inferior graft outcomes in patients with kidney transplants. We studied baseline patterns of tacrolimus intrapatient variability in pediatric patients with kidney transplants and examined these patterns in relation to C1q-binding de novo donor-specific antibodies. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: All tacrolimus levels in participants who underwent kidney-only transplantation at a single pediatric center from 2004 to 2018 (with at least 12-month follow-up, followed until 2019) were analyzed to determine baseline variability. Intrapatient variability was defined using the coefficient of variation (SD/mean ×100%) of all samples in a 6-month moving window. Routine de novo donor-specific antibody measurements were available for a subgroup of patients transplanted in 2010-2018. Cox proportional hazards models using tacrolimus intrapatient variability as a time-varying variable were used to examine the association between intrapatient variability and graft outcomes. The primary outcome of interest was C1q-binding de novo donor-specific antibody formation. RESULTS: Tacrolimus intrapatient variability developed a steady-state baseline of 30% at 10 months post-transplant in 426 patients with a combined 31,125 tacrolimus levels. Included in the outcomes study were 220 patients, of whom 51 developed C1q-binding de novo donor-specific antibodies. De novo donor-specific antibody formers had higher intrapatient variability, with a median of 38% (interquartile range, 28%-48%) compared with 28% (interquartile range, 20%-38%) for nondonor-specific antibody formers (P<0.001). Patients with high tacrolimus intrapatient variability (coefficient of variation >30%) had higher risk of de novo donor-specific antibody formation (hazard ratio, 5.35; 95% confidence interval, 2.45 to 11.68). Patients in the top quartile of tacrolimus intrapatient variability (coefficient of variation >41%) had the strongest association with C1q-binding de novo donor-specific antibody formation (hazard ratio, 11.81; 95% confidence interval, 4.76 to 29.27). CONCLUSIONS: High tacrolimus intrapatient variability was strongly associated with de novo donor-specific antibody formation.