Faculty Bibliography

INTRODUCTION/BACKGROUND:Predicting graft failure risk in pediatric liver transplantation (LT) recipients could identify areas for improving management. Persistent cognitive, motor, academic, and functional deficits are common in recipients and their impact on graft survival following LT helps inform risk prediction. METHODS:Using SRTR data 2008-2023, we evaluated the cognitive, motor, academic, and functional deficits of LT recipients at time of transplant to 14 years post-LT. We compared all cause graft failure (ACGF) among patients with versus without pre-LT and 1-year post-LT deficits using Cox regression, adjusting for recipient characteristics. We calculated an individual risk score for ACGF. RESULTS:In 8062 pediatric LT recipients median age 3 (IQR: 1, 10), 28.0%, 29.5%, 35.0%, and 79.8% of recipients had pre-LT deficits in cognition, motor, academic activity, and functional status respectively. This decreased to 23.0%, 18.1%, 14.2%, and 38.7% 1-year post-LT. Increased hazard of ACGF was noted in recipients with pre-LT decreased functional status (aHR = 1.13 (per 10% decrease), 95% CI: 1.10-1.15, p < 0.001), definite motor delay (aHR = 1.60, 95% CI: 1.21-2.10, p < 0.001), and inability to participate in academics (aHR = 1.49, 95% CI: 1.08-1.89, p = 0.01), but not delays in cognition (aHR = 0.91, 95% CI: 0.69-1.21, p = 0.19). Our risk score predicting ACGF demonstrated improved predictive performance compared to clinical parameters alone (C-statistic = 0.70 (0.67, 0.72) vs. 0.66 (0.64, 0.69), p < 0.001). CONCLUSIONS:Pediatric LT recipients with pre- or post-LT motor, academic, and functional deficits are at higher risk for ACGF. Care should be taken to assess deficits to identify patients who may benefit from functional intervention to potentially reduce ACGF risk.

BACKGROUND:Organ Procurement and Transplantation Network (OPTN) policy requires 2 years of follow-up for living kidney donors (LKDs); however, many transplant hospitals struggle to meet this requirement. We developed and tested a mobile health (mHealth) system for LKD follow-up in a pilot randomized-controlled trial (RCT). METHODS:LKDs were randomly assigned to either the intervention (mHealth + standard of care) or control arm (standard of care). We assessed OPTN policy-defined completeness and timeliness of 6-month, 1-year, and 2-year follow-ups. Four hundred LKDs were enrolled in the study (June 2018 to February 2021). RESULTS:At 6-month follow-up, a higher proportion of the intervention arm participants completed composite visits (97.5% vs. 91.5%, p = 0.01). Both arms had similar compliance rates at 1- and 2-year follow-up (92.0% vs. 89.5%, p = 0.49, and 66.5% vs. 65.0%, p = 0.83). Intervention arm participants completed 6-month follow-up 11 days earlier than their counterparts (p = 0.009). CONCLUSION/CONCLUSIONS:mHealth technologies improved 6-month follow-up, but did not impact 1- and 2-year LKD follow-up in this single-center RCT. Other strategies, such as providing services beyond data collection, may be necessary to improve donor engagement and support LDK's long-term follow-up.

People with HIV have higher risk for rejection after kidney transplantation but the mechanism is poorly understood. As HIV latency promotes immune dysregulation and chronic inflammation, we evaluated whether the size of the HIV latent viral reservoir (LVR) at baseline and through 52-weeks is associated with rejection in kidney transplant recipients with HIV from donors with and without HIV. Using the intact proviral DNA assay, we found no differences in the LVR between those who experienced rejection (n=14) versus those who did not (N=55) regardless of donor HIV status. These data support the feasibility of HIV+ to HIV+ organ transplantation. Clinical Trials Registration. NCT03500315.

Normothermic machine perfusion (NMP) may increase utilization of non-ideal donor kidneys through improved preservation and assessment. We assessed the use of a centralized perfusion service to rescue declined kidneys for transplant. Kidneys that exhausted standard OPTN allocation underwent 2 hours of NMP for additional assessment. The primary outcome was rescue for transplantation. Outcomes of NMP kidneys were compared to non-NMP kidneys transplanted during the study period at the same transplant centers. NMP was performed on 104 declined kidneys, and 94 (90%) were rescued for transplant. NMP donors were older, with a higher kidney donor profile index (KDPI) compared to non-NMP donors. Cold ischemia time was significantly longer in the NMP cohort (median 37.6 vs. 22.1 hours, p<0.001). The weighted percentage of delayed graft function (DGF) was 26.3% in the NMP group vs 60.2% in the non-NMP group (p=0.023). Overall graft survival was similar between the groups. With the use of a centralized NMP service, kidneys declined based on standard clinical parameters may be evaluated, rescued, and successfully transplanted. Kidneys undergoing NMP experienced significantly lower rates of DGF compared to non-NMP kidneys. Additional follow up is needed to determine the effects of NMP on long-term graft function.

Liver transplant (LT) recipients experience a wide range of comorbidities, leading to frequent healthcare encounters. Until now, national registries, which have limited exposures and outcomes, and laborious small cohort studies have been the main data sources for LT research. Cosmos database offers electronic health record (EHR)-based insights into LT recipients at the national level with granular data. We evaluated if Cosmos data is representative of the entire US LT recipient population. Using Cosmos (N=20,235) and the national Scientific Registry of Transplant Recipients (SRTR) (N=51,281), we identified adult, first-time LT recipients between 7/2016-12/2022. We compared demographics, clinical data, and mortality across datasets, calculating Kaplan-Meier survival estimates and multi-variable Cox regressions. Recipient characteristics were highly comparable (e.g., female: Cosmos=36.5% vs. SRTR=36.4%, Black: 6.8% vs. 7.2%; BMI: 28.5 kg/m2 [24.8-32.9] vs. 28.2 [24.6-32.4]). Lab values were similar across cohorts, including MELD (24 [17-30] vs. 23 [16-30]). Transplant indications, donor characteristics, and 5-year survival (Cosmos 83.1% [82.3-83.8) vs. SRTR 80.9% [80.4-81.3]) were similar. The associations of clinical factors with survival were similar across both groups. Cosmos database demonstrated acceptable generalizability to the general US LT recipient population, which may advance LT research through a better understanding about LT recipients' experiences and outcomes.

BACKGROUND:Access to liver transplantation (LT) for pediatric registrants is complex and impacted by many factors. Assessing the state of pediatric LT requires understanding the balance between policy, the availability of livers, and the quantity of pediatric patients requiring LT. METHODS:Using Scientific Registry of Transplant Recipients data with Cox regression (to compare rates) and competing risk regression (to compare cumulative incidence), we evaluated pediatric patient characteristics, number of registrants transplanted, and waitlist mortality from (January 1, 2017-February 4, 2020) to (May 1, 2020-June 4, 2023) using the implementation of acuity circles to divide the eras. RESULTS:In 4314 pediatric LT registrants, transplantation rate increased in the post-policy era, compared with the pre-policy era (adjusted hazard ratio [HR], 1.05 1.12 1.20 ; P  < 0.001). When accounting for competing risks, the increase was attenuated and not statistically significant (adjusted subdistribution HR, 0.99 1.06 1.14 ; P  = 0.08); recipients were no more likely to die on the waitlist (adjusted subdistribution HR, 0.78 1.01 1.30 ; P  = 0.99). Importantly, the prevalent pediatric waitlist dropped from 396 (2017) to 225 (2023), the rate of deceased donor LT from pediatric donors increased (weighted HR, 1.20 1.31 1.42 ; P  < 0.001), and access to living donor LT increased, compared with the pre-policy era (weighted HR, 1.11 1.33 1.59 ; P  = 0.002). The transplant rate for pediatric patients did not decrease during the study period despite the introduction of acuity circles. During the study period, the prevalent waitlist shrank, access to LT from pediatric donors increased, and access to living donor LT increased. CONCLUSIONS:Comprehensive assessment following the policy change is necessary to ensure that pediatric candidates maintain priority. Changes in pediatric transplantation are modest and likely related to changes in the pool, rather than to the policy of acuity circles.

BACKGROUND:Left-sided kidneys are preferred for living donor kidney transplant (LDKT) because their longer renal vein leads to greater technical ease. Nevertheless, right-sided nephrectomies are performed when favorable for donors. We evaluated national and center-level trends in right living donor nephrectomy. METHODS:We used SRTR data to identify all LDKTs from 1995-2024 and calculated annual proportions of right kidneys. Then analyzing the contemporary 10-year period (2015-2024), we calculated the Pearson correlation coefficient between center-level LDKT volume and proportion of right-sided nephrectomies. We also assessed the effect of Kidney paired donation (KPD) on proportion of right kidneys used at the center and national levels. We also compared the incidence of delayed graft function (DGF) and 90-day graft failure. RESULTS:= 0.02). KPDs involved a greater proportion of right kidneys compared to direct donations (12% vs. 11%, p = 0.003). Additionally, even in the contemporary era, right-sided LDKTs had higher incidence of DGF (2.4% vs. 1.3%) and 90-day graft failure (8.7% vs. 5.2%) compared to left-sided LDKTs (both p < 0.01). CONCLUSIONS:Center-level variation in right LDKTs likely reflects different thresholds in accepting anatomic complexity or split function and is independent from overall center volume. Further, despite advances in laparoscopic LDKT, right kidneys remain associated with early graft dysfunction in the contemporary era.

Hypothermic machine perfusion (HMP) has surged in popularity for donor kidney preservation. Continuous-HMP (cHMP) has shown clear benefits over static cold storage (SCS), whereas randomized trials on short-duration end-ischemic-HMP (eiHMP) have not. We assessed whether HMP modulates injury from increasing cold-preservation-time and analyzed the impact of HMP on short- and long-term outcomes, using OPTN data (2010-2024) on single-kidney-transplant recipients (n=137,835). Multivariable non-linear (restricted cubic spline) regression with interaction terms were used. Median cold-preservation-time was long (17.3hrs,IQR:12.0-22.9), especially in the eiHMP cohort (median=23.0hrs,IQR:17.3-30.5). HMP was associated with significant reductions in DGF (cHMP:aOR=0.484,95%CI=0.467-0.501; eiHMP:aOR=0.459,95%CI=0.435-0.485; transport-only-HMP:aOR=0.535,95%CI=0.512-0.558) and LOS. Interaction analyses revealed HMP mitigated the negative effect of increasing cold-preservation-time compared with SCS. cHMP showed benefit across all cold-preservation-times, whereas eiHMP was beneficial only at longer cold-preservation-times. HMP was also associated with improved 5-year graft and patient survival. In conclusion, HMP reduces the negative impact of each additional hour of cold-preservation-time. Therefore, the treatment effect is not fixed and increases as cold-preservation-time increases, likely explaining the lack of benefit in trials of short-duration eiHMP. The association with improved 5-year graft survival and mortality provides IDEAL stage 4 evidence. This study addresses questions beyond the reach of randomized trials but of clear clinical relevance.