Impact of age over 70 years in the new allocation system on the outcomes of heart transplantation in the US

BACKGROUND

United Network for Organ Sharing (UNOS) allocation criteria changed in 2018 to accommodate the increased prevalence of patients on a ventricular assist device as a bridge to heart transplant and prioritize sicker people in anticipation of a heart graft. We aimed to assess the impact of patient age in the new allocation policy on mortality following heart transplantation. Secondary outcomes included the effect of age ≥70 on post-transplant events, including stroke, dialysis, pacemaker, and rejection requiring treatment.

METHODS

The UNOS Registry was queried to identify patients who underwent heart transplants alone in the US between 2000 and 2021. Patients were divided into groups according to their age (over 70 and under 70 years old).

RESULTS

Patients aged over 70 were more likely to require dialysis during follow-up, but less likely to experience rejection requiring treatment, compared with patients aged <70. Age ≥70 in the new allocation system was a significant predictor of 1-year mortality (adjusted HR: 1.41; 95% CI: 1.05-1.91; p = .024), but its effect on 5-year mortality was not significant after adjusting for potential confounders (adjusted HR: 1.27; 95% CI:.97-1.66; p = .077). Undergoing transplantation under the new allocation policy vs the old allocation policy was not a significant predictor of mortality in patients over 70 years old.

CONCLUSIONS

Age ≥70 is a significant predictor of 1-year mortality following heart transplantation, but not at 5 and 10 years; however, the new allocation does not seem to have changed the outcomes for this group of patients.

Influence of cardiac diagnosis on outcomes of pediatric heart-lung transplantation

OBJECTIVE

Pediatric Heart-lung transplant (HLTX) is performed for endstage congenital heart disease (CHD) with irreversible pulmonary hypertension or non-congenital heart disease (NCHD) with end-stage heart and lung disease. CHD could influence the outcomes of HTLX due to increased complexity of the operation as compared to NCHD. In this study we evaluated the influence of cardiac diagnosis on outcomes of pediatric HTLX.

METHODS

The UNOS database (1987-2022) was queried for primary HTLX in patients <18 years. The data were extracted for demographics, pretransplant characteristics, post-transplant outcomes, and analyzed for the impact of cardiac diagnosis on post-transplant outcomes. Standard statistical tests were used. Survival was compared using the Kaplan-Meier method.

RESULTS

Ninety of the 213 patients who underwent HLTX had CHD. There were no demographic differences. Heart listing status was similar but with a higher LAS score for NCHD. NCHD had higher pre-operative life support use (mechanical ventilation, inotropes or dialysis) but the use of ECMO as a bridge to transplantation was similar. Wait-list times were longer for CHD. The ischemic times were similar. Post-transplant dialysis, stroke, prolonged mechanical ventilation, and rejection were similar. Survival at 30-days, 1-year, and long-term survival at 17 years was similar. Non-survivors at 30-days post-transplant were on life support, used ECMO as a bridge, had lower wait-list times, longer ischemic times and had strokes. Non-survivors at 1-year had similar factors in addition to a higher dialysis use.

CONCLUSION

Cardiac diagnosis had no impact on outcomes after Pediatric HLTX. Patients on life support or ECMO before transplantation were transplanted faster but with lower survival.

Impact of race-neutral eGFR calculations on African American kidney transplant candidate wait time: A single center retrospective analysis

Race-inclusive estimated glomerular filtration rate (eGFR) could contribute to racial disparity in access to kidney transplantation. The Organ Procurement and Transplantation Network (OPTN) issued a policy allowing waiting time modification for candidates affected by race-inclusive eGFR calculations. Implementation of the new OPTN policy at the kidney transplant program of the Mount Sinai Hospital involved review of 921 African American candidates, of whom 240 (26%) candidates gained a median of 1 year and 10 months. The duration of time candidates gained varied from a minimum of 5 days to a maximum of 12 years and 3 months; 45.4% gained at least 2 years, and 12% gained at least 4 years of wait time. Among those who gained wait time, 20 (8.3%) candidates received deceased donor kidney transplants. Candidates who gained wait time had similar sociodemographic characteristics as those who did not, except that the median age for the former was higher by 3 years (59 vs. 56). Our early data suggest that the current policy on waiting time modification for candidates affected by race-inclusive estimation of GFR has the potential to improve racial disparity in access to kidney transplantation. However, the generalizability of our findings to other centers requires further study.

The short and long-term prognostic influences of liver grafts with high bilirubin levels at the time of organ recovery

BACKGROUND

Donors with hyperbilirubinemia are often not utilized for liver transplantation (LT) due to concerns about potential liver dysfunction and graft survival. The potential to mitigate organ shortages using such donors remains unclear.

METHODS

This study analyzed adult deceased donor data from the United Network for Organ Sharing database (2002-2022). Hyperbilirubinemia was categorized as high total bilirubin (3.0-5.0 mg/dL) and very high bilirubin (≥5.0 mg/dL) in brain-dead donors. We assessed the impact of donor hyperbilirubinemia on 3-month and 3-year graft survival, comparing these outcomes to donors after circulatory death (DCD).

RESULTS

Of 138 622 donors, 3452 (2.5%) had high bilirubin and 1999 (1.4%) had very high bilirubin levels. Utilization rates for normal, high, and very high bilirubin groups were 73.5%, 56.4%, and 29.2%, respectively. No significant differences were found in 3-month and 3-year graft survival between groups. Donors with high bilirubin had superior 3-year graft survival compared to DCD (hazard ratio .83, p = .02). Factors associated with inferior short-term graft survival included recipient medical condition in intensive care unit (ICU) and longer cold ischemic time; factors associated with inferior long-term graft survival included older donor age, recipient medical condition in ICU, older recipient age, and longer cold ischemic time. Donors with ≥10% macrosteatosis in the very high bilirubin group were also associated with worse 3-year graft survival (p = .04).

DISCUSSION

The study suggests that despite many grafts with hyperbilirubinemia being non-utilized, acceptable post-LT outcomes can be achieved using donors with hyperbilirubinemia. Careful selection may increase utilization and expand the donor pool without negatively affecting graft outcome.

Do outcomes for heart transplantation differ based on donor and recipient race?

PURPOSE

There are limited data examining the impact of both donor and recipient race on outcomes following orthotopic heart transplant (OHT). The purpose of this study was to evaluate the relationship between donor and recipient race and OHT outcomes.

METHODS

The United Network for Organ Sharing (UNOS) database was retrospectively reviewed from January 2000 to March 2018 for donor hearts. A comparison was conducted based on donor and recipient race (White, Black, Hispanic, Other/Unknown). Races for which there were limited numbers were excluded from the analysis (Asian, n = 1292; American Indian, n = 132; Pacific Islander, n = 132, Multiple ethnicities, n = 225). The primary endpoint was survival at 30 days, 1 year survival, and post-transplant rejection. Logistic and Cox models were used to quantify survival endpoints.

RESULTS

A total of 41 841 OHT were included. Of the recipients, 29 894 (71%) were White, 8475 (20%) were Black, and 3472 (8%) were Hispanic. Of the donors 27 783 (66%) were White, 6277 (15%) were Black, 6576 (16%) were Hispanic, and 1205 (3%) were Unknown/Other race. In a comparison of recipient demographics, White recipients were older (54.09 ± 12.21 years) compared to Black (49.44 ± 12.83 years) and Hispanic (49.97 ± 13.27 years) recipients. All other differences between groups were not clinically significant. Black recipients were more likely to receive a heart with an "urgent" status (probability .80) compared to White (.73) and Hispanic (.75) recipients (p < .001). Hispanic recipients were more likely to receive a transplant when listed as "non-urgent" (Probability .47) compared to White (.37) and Black (.30) recipients (p < .001). In terms of outcomes, compared to White recipients, Hispanic patients experienced a decreased 30-day survival (OR 1.27; p = .011) and 1-year survival (OR 1.17; p = .016). In comparing Donor/Recipient combinations compared to a White Donor/White Recipient combination, overall survival was decreased in White donor/African American recipient (HR 1.36; p < .001), African American donor/African American recipient (HR 1.41; p < .001) and Hispanic donor/African American recipient (HR 1.30; p < .001) combinations (Table 1).

CONCLUSIONS

African American and Hispanic recipients have decreased survival compared to White recipients after heart transplant. The African American donor does not decrease survival. Racial differences still exist in donor and recipient characteristics and recipient outcomes after OHT. Increasing the donor pool for all races and ethnicities would potentially benefit all recipients. Continued study is warranted in order to minimize these differences among recipients and identify factors that could be contributing to decreased survival, in order to optimize outcomes for African American and Hispanic recipients post-transplant and eliminate disparities.

Predicted heart mass based on ideal body weight for donor-to-recipient size matching

BACKGROUND

Predicted heart mass (PHM) is a commonly used tool for donor-to-recipient size matching. However, incorporating body weight as part of PHM can be considered problematic given its high variability, and low metabolic nature of fat. We sought to assess whether substituting the actual donor and recipient weight with the ideal body weight (IBW) would affect the association of donor-to-recipient PHM ratio with 1-year and overall survival after heart transplantation.

METHODS

The United Network for Organ Sharing (UNOS) database was queried for adult patients who received a primary heart transplant between January 2000 and September 2021.

RESULTS

Both PHM and ideal PHM (IPHM) ratios were associated with one-year (PHM: p = .003; IPHM: p = .0007) and overall (PHM: p = .02; IPHM: p = .02) survival. In the continuous analysis with restricted cubic splines, both PHM (p = .0003) and IPHM (p = .00001) were associated with relative hazards of death.

CONCLUSION

IPHM is significantly associated with post-transplant survival and may be a useful compliment to PHM.

Impact of new allocation system on length of stay following heart transplantation in the United States

BACKGROUND

United Network for Organ Sharing (UNOS) allocation criteria changed in 2018 to accommodate the increased prevalence of ventricular assist device use as a bridge to heart transplant, which consequently prioritized sicker patients. We aimed to assess the impact of this new allocation policy on the length of stay following heart transplantation. Secondary outcomes include other risk factors for prolonged hospitalization and its effect on mortality and postoperative complications.

METHODS

The UNOS Registry was queried to identify patients who underwent isolated heart transplants in the United States between 2001 and 2023. Patients were divided into quartiles according to their respective length of stay.

RESULTS

A total of 57 020 patients were included, 15 357 of which were allocated with the new system. The median hospital length of stay was 15 days (mean 22.7 days). Length of stay was longer in the new allocation era (25 ± 30 vs. 22 ± 27 days, p < .001). The longer length of stay was associated with increased 5-year mortality in the new allocation system (aHR: 1.18; 95% CI: 1.15, 1.20; p-value: < .001).

CONCLUSION

Longer hospital stays and associated observed increased risk for mortality in the era after the allocation criteria change reflect the rationale of this shift which was to prioritize heart transplants for sicker patients. Further studies are needed to track the progress of surgical and perioperative management of these studies over time.

Impact of donor-recipient age-difference in adolescent heart transplantation

INTRODUCTION

The relationship between donor age and adolescent heart transplant outcomes remains incompletely understood. We aimed to explore the effect of donor-recipient age difference on survival after adolescent heart transplantation.

METHODS

The United Network for Organ Sharing database was used to identify 2,855 adolescents aged 10-17 years undergoing isolated primary heart transplantation from 1/1/2000 to 12/31/2022. The primary outcome was 10-year post-transplant survival. Multivariable Cox regression identified predictors of mortality after adjusting for donor and recipient characteristics. A restricted cubic spline assessed the non-linear association between donor-recipient age-difference and the adjusted relative mortality hazard.

RESULTS

The median donor-recipient age-difference was +3 (range -13 to +47) years, and 17.7% (n = 504) of recipients had an age- difference > 10 years. Recipients with an age-difference > 10 years had a less favorable pre-transplant profile, including a higher incidence of priority status 1A (81.6%, n = 411 vs. 73.6%, n = 1730; p = .01). The 10-year survival rate was 54.6% (95% confidence interval (CI) 48.8- 60.4) among recipients with a donor-recipient age-difference > 10 years and 66.9% (95% CI: 64.4-69.4) among those with an age-difference ≤10 years. An age-difference > 10 years was an independent predictor of mortality (hazard ratio 1.43, 95% CI: 1.18-1.72, p < .001). Spline analysis demonstrated that the adjusted mortality hazard increased with increasingly positive donor-recipient age-difference and became significantly higher at an age-difference of 11 years.

CONCLUSION

A donor-recipient age-difference > 11 years is independently associated with higher long-term mortality after adolescent heart transplantation. This finding may help inform acceptable donor selection practice for adolescent heart transplant candidates.

Repeat pediatric heart transplantation: A united network for organ sharing database analysis

BACKGROUND

A history of congenital heart disease and previous transplantation are each independently associated with worse survival following pediatric heart transplantation. This study aimed to evaluate the characteristics and outcomes of children undergoing repeat heart transplantation in the United States based on the underlying diagnosis.

METHODS

The United Network for Organ Sharing database was used to identify 8111 patients aged <18 years undergoing isolated heart transplantation from 2000 to 2021, including 435 (5.4%) repeat transplants. Restricted cubic spline analysis assessed the non-linear relationship between inter-transplant interval and the primary outcome of all-cause mortality or re-transplantation. Multivariable Cox regression assessed the impact of re-transplantation on the primary outcome. Median follow-up was 5.0 (interquartile range 1.9-9.9) years.

RESULTS

Repeat transplant patients were older (median age 12 vs. 4 years; p < .001), and less likely to be in UNOS status 1A (66.0%, n = 287 vs. 81.0% n = 6217; p < .001) than primary transplant patients. Freedom from the primary outcome was 51.4% (95% confidence interval [CI] 45.5-57.2) among repeat transplants and 70.5% (95% CI 69.2-71.8) among primary transplants at 10 years (p < .001). Among repeat transplant patients, the relative hazard of the primary outcome became non-significant when the inter-transplant interval >3.6 years. Congenital heart disease was an independent predictor of mortality among primary (HR 1.8, 95% CI 1.6-1.9) but not repeat transplant (HR 1.1, 95% CI .8-1.6) patients.

CONCLUSIONS

Long-term outcomes remain poor for patients undergoing repeat heart transplantation, particularly those with an inter-transplant interval <3.6 years. Underlying diagnosis does not impact outcomes after repeat transplantation, after accounting for other risk factors.

Sex differences in clinical characteristics and outcomes in patients undergoing heart transplantation

AIMS

Whether sex affects selection for and outcomes after heart transplantation (HTx) remains unclear. We aimed to show sex differences in pre-transplant characteristics and outcomes after HTx.

METHODS AND RESULTS

From 1995 to 2019, 49 200 HTx recipients were prospectively enrolled in the Organ Procurement and Transplantation Network. Logistic regression models were used to evaluate clinical characteristics by sex. Multivariable Cox regression models were fitted to assess sex differences in all-cause mortality, cardiovascular mortality, graft failure, cardiac allograft vasculopathy (CAV), and malignancy. In 49 200 patients (median age 55 years, interquartile range 46-62; 24.6% women), 49 732 events occurred during a median follow-up of 8.1 years. Men were older than women, had more often ischaemic cardiomyopathy (odds ratio [OR] 3.26, 95% confidence interval [CI] 3.11-3.42; P < 0.001), and a higher burden of cardiovascular risk factors, whereas women had less malignancies (OR 0.47, CI 0.44-0.51; P < 0.001). Men were more often treated in intensive care unit (OR 1.24, CI 1.12-1.37; P < 0.001) with a higher need for ventilatory (OR 1.24, CI 1.17-1.32; P < 0.001) or VAD (OR 1.53, CI 1.45-1.63; P < 0.001) support. After multivariable adjustment, men had a higher risk for CAV (hazard ratio [HR] 1.21, CI 1.13-1.29; P < 0.001) and malignancy (HR 1.80, CI 1.62-2.00; P < 0.001). There were no differences in all-cause mortality, cardiovascular mortality, and graft failure between sexes.

CONCLUSIONS

In this US transplant registry, men and women differed in pre-transplant characteristics. Male sex was independently associated with incident CAV and malignancy even after multivariable adjustment. Our results underline the need for better personalized post-HTx management and care.

The real unmet need: A multifactorial approach for identifying sensitized kidney candidates with low access to transplant

BACKGROUND

At the start of 2020, the kidney waiting list consisted of 2526 candidates with a calculated panel reactive antibody (CPRA) of 99.9% or greater, a cohort demonstrated in published research to have meaningfully lower than average access to transplantation even under the revised kidney allocation system (KAS).

METHODS

This was a retrospective analysis of US kidney registrations using data from the OPTN [Reference (https://optn.transplant.hrsa.gov/data/about-data/)]. The period-prevalent study cohort consisted of US kidney-alone registrations who waited at least 1 day between April 1, 2016, when HLA DQ-Alpha and DP-Beta unacceptable antigen data became available in OPTN data collection, to December 31, 2019. Poisson rate regression was used to model deceased donor kidney transplant rates per active year waiting and using an offset term to account for differential at-risk periods. Median time to transplant was estimated for each IRR group using the Kaplan-Meier method. Sensitivity analyses were included to address geographic variation in supply-to-demand ratios and differences in dialysis time or waiting time.

RESULTS

In this study, we found 1597 additional sensitized (CPRA 50-<99.9%) candidates with meaningfully lower than average access to transplant when simultaneously taking into account CPRA and other factors. In combination with CPRA, candidate blood type, Estimated Post-Transplant Survival Score (EPTS), and presence of other antibody specificities beyond those in the current, 5-locus CPRA were found to influence the likelihood of transplant.

CONCLUSION

In total, this suggests approximately 4100 sensitized candidates are on the waiting list who represent a community of disadvantaged patients who may benefit from progressive therapies and interventions to facilitate incompatible transplantation. Though associated with higher risks, such interventions may nevertheless be more attractive than remaining on dialysis with the associated accumulation of mortality risk over time.

Does donor treatment with inotropes and/or vasopressors impact post-transplant outcomes?

PURPOSE

The purpose was to evaluate the effects of the most commonly used cardiac donor inotropes/vasopressors on subsequent post-heart transplant survival.

METHODS

Adult heart transplant recipients from January 2000 to June 2022 were identified in the United Network for Organ Sharing (UNOS) database. Exclusion criteria included: multiorgan transplants, donor age < 15, and recipient age < 18. Donors receiving vasoactive medications at the time of procurement were compared to donors not receiving these medications. Those on vasoactive medications were stratified by medication: phenylephrine, dopamine, dobutamine, norepinephrine and epinephrine, the combination of these agents, and the concomitant administration of vasopressin with any single agent alone or in combination. The primary area of interest was short-and-long-term survival. Survival at 30 days, 1 year, and long-term (Median = 13.6 years) was compared using logistic and Cox models to quantify survival endpoints.

RESULTS

A total of 45,198 donors met inclusion criteria and had data on the use of vasoactive agents available. Mean donor age was 32.3 years with 71% male. Vasoactive medications and potential combinations included phenylephrine in 8156 donors (18.0%), dopamine in 9550 (21.1%), dobutamine in 718 (1.6%), epinephrine in 332 (.73%), and norepinephrine in 4854 (10.7%). A total of 25,856 donors (57.2%) were receiving vasopressin at the time of procurement. There was no impact of donor inotropes on 30-day survival. Donors receiving one inotrope and no vasopressin were associated with increased 1 year mortality (OR 1.14; p = .021), as were donors receiving 2+ inotropes and no vasopressin (OR 1.26; p = .006). For individual agents, 1 year mortality was increased for dopamine (OR 1.11; p = .042) and epinephrine (OR 1.59; p = .004).

CONCLUSIONS

There is no difference in heart transplant recipient survival at 30 days when the donor is receiving inotropes without vasopressin at the time of procurement. Inotropic support without vasopressin is associated with greater 1 year mortality. The impact of donor inotropic support on long term heart transplant survival, and the interaction with vasopressin warrants further study.

Examining the transplant case composition of early-career transplant surgeons

Fellowship training established by the American Society of Transplant Surgeons and certified by the Transplant Accreditation and Certification Council provides trainees with broad exposure and practice readiness for the core aspects of abdominal transplantation. However, the operative case mix of a new transplant surgeon early in practice is unknown. This study examined the volume and composition of the transplant case mix of early-career transplant surgeons to better inform residents interested in transplantation about potential career opportunities following fellowship. cas 209 early-career transplant surgeons were identified from the UNOS database containing encrypted surgeon-specific identifiers and were included in this study. At 5 years into practice, there were 85 (40.7%) kidney-predominant, 38 (18.2%) liver-predominant, and 86 (41.1%) multiorgan transplant surgeons. Comparing surgeon subgroups, multiorgan surgeons performed more transplants in year 5 of practice than both liver-predominant and kidney-predominant surgeons (both p < .05). This is the first study to describe the transplant case composition of the early-career transplant surgeons. This data can be used to inform aspiring transplant surgeons about potential career opportunities and to assist fellowship programs in guiding and mentoring fellows.

Information design to support growth, quality, and equity of the US transplant system

The Organ Procurement and Transplantation Network, an arm of the Health Resources and Services Administration, has a contract with the United Network for Organ Sharing since 1986 to provide central oversight of organ donation and transplants in the United States. The United Network for Organ Sharing has recently come under scrutiny, prompting a review by the National Academies of Sciences, Engineering, and Medicine as summarized in its recent report and also by the US Senate Finance Committee. The national news services have opined about organ donation ethics, access to transplantation particularly for medically underserved populations, and management of organ transplantation data. These critiques raise important concerns that deserve our best response as a transplant community. Broadly, we suggest that the data management approach of the Organ Procurement and Transplantation Network be replaced with a patient-centric omnichannel network in which all donor and recipient data exist in a single longitudinal record that can be used by all applications. A more comprehensive and standardized approach to donor data collection would drive quality improvement across organ procurement organizations and help address inequities in transplantation. Finally, a substantial increase in organ donation would be prompted by considering organ donors as a public health resource, meriting transparent publicly available data collection with respect to organ donor referral, screening, and management.

UNOS policy change benefits high-priority patients without harming those at low priority

The heart transplantation policy change (PC) has improved outcomes in high-acuity (Old 1A, New 1-3) patients, but the effect on low-priority (Old 1B/2, New 4-6) patients is unknown. We sought to determine if low-priority patient outcomes were compromised by benefits to high-priority patients by evaluating for interaction between PC and priority status (PS). We included adult first-time heart transplant candidates and recipients from the UNOS registry during a 19-month period before and after the PC. We compared clinical characteristics and performed competing risks and survival analyses stratified by PC and PS. There was a dependence of PC and PS on waitlist death/deterioration with an interaction sub-distribution hazard ratio (adjusted sdHR) of 0.59 (0.45-0.78), p-value < .001. There was a trend toward a benefit of PC on waitlist death/deterioration (adjusted sdHR: 0.86 [0.73-1.01]; p = .07) and an increase in heart transplantation (adjusted sdHR: 1.08 [1.02-1.14], p = .007) for low-priority patients. There was no difference in 1-year post-transplant survival (log-rank p = .22) when stratifying by PC and PS. PC did not negatively affect waitlisted or transplanted low-priority patients. High-priority, post-PC patients had a targeted reduction in waitlist death/deterioration and did not come at the expense of worse post-transplant survival.

Awarding additional MELD points to the shortest waitlist candidates improves sex disparity in access to liver transplant in the United States

Since the introduction of the MELD-based allocation system, women are now 30% less likely than men to undergo liver transplant (LT) and have 20% higher waitlist mortality. These disparities are in large part due to height differences in men and women though no national policies have been implemented to reduce sex disparities. Patients were identified using the Scientific Registry of Transplant Recipients (SRTR) from 2014 to 2019. Patients were categorized into five groups by first dividing into thirds by height then dividing the shortest third into three groups to capture more granular differences in the most disadvantaged patients (<166 cm). We then used LSAM to model waitlist outcomes in five versions of awarding additional MELD points to shorter candidates compared to current policy. We identified two proposed policy changes LSAM scenarios that resulted in improvement in LT and death percentage for the shortest candidates with the least negative impact on taller candidates. In conclusion, awarding an additional 1-2 MELD points to the shortest 8% of LT candidates would improve waitlist outcomes for women. This strategy should be considered in national policy allocation to address sex-based disparities in LT.

Center-level and region-level variations in liver transplantation practices following acuity circles policy change

Although early studies suggest the Acuity Circles (AC) allocation policy has increased access to deceased donor liver transplants (DDLTs) for patients with the highest MELD scores, changes in center- and region-level practices among patients with the highest MELD scores in response to AC are not well-characterized. OPTN/UNOS data were analyzed to compare center-level changes in the number of DDLTs based on allocation-MELD (aMELD) categories used for AC sharing performed in the 18-month periods before and after AC enactment on February 4, 2020. There was large center-level variation in the number and proportion of aMELD ≥ 37 DDLTs performed from pre-AC to AC period; 13 centers accounted for 196 of the 198 total net increase in aMELD ≥ 37 DDLTs performed after AC, 5 of these being from UNOS region 5. Similar center-level variation was seen for MELD 33-36 and MELD 29-32 DDLTs, with 17 centers and 14 centers, respectively, accounting for the entire net increase in DDLTs in the aMELD categories. In conclusion, AC increased access to livers for transplantation for high MELD patients nationally, but imbalances remain in transplant practice patterns at the center and regional levels. Longer-term study is necessary to assess effectiveness of AC in improving equitability of liver transplantations.

Social determinants of health data in solid organ transplantation: National data sources and future directions

Health equity research in transplantation has largely relied on national data sources, yet the availability of social determinants of health (SDOH) data varies widely among these sources. We sought to characterize the extent to which national data sources contain SDOH data applicable to end-stage organ disease (ESOD) and transplant patients. We reviewed 10 active national data sources based in the United States. For each data source, we examined patient inclusion criteria and explored strengths and limitations regarding SDOH data, using the National Institutes of Health PhenX toolkit of SDOH as a data collection instrument. Of the 28 SDOH variables reviewed, eight-core demographic variables were included in ≥80% of the data sources, and seven variables that described elements of social status ranged between 30 and 60% inclusion. Variables regarding identity, healthcare access, and social need were poorly represented (≤20%) across the data sources, and five of these variables were included in none of the data sources. The results of our review highlight the need for improved SDOH data collection systems in ESOD and transplant patients via: enhanced inter-registry collaboration, incorporation of standardized SDOH variables into existing data sources, and transplant center and consortium-based investigation and innovation.

National Experience on Waitlist Outcomes for Down-Staging of Hepatocellular Carcinoma: High Dropout Rate in All-Comers

BACKGROUND & AIMS

The United Network for Organ Sharing (UNOS) grants priority listing for liver transplant for patients with hepatocellular carcinoma after successful down-staging to Milan criteria. We evaluated the national experience on down-staging by comparing 2 down-staging groups: tumor burden meeting UNOS down-staging (UNOS-DS) inclusion criteria, and all-comers (AC)-DS with initial tumor burden beyond UNOS-DS criteria vs patients always within Milan criteria.

METHODS

We performed a retrospective analysis of the UNOS database of 23,398 patients listed for liver transplant who had submitted a hepatocellular carcinoma Model for End-Stage Liver Disease exception application from 2010 to 2019, classified as always within Milan (n = 20,579), UNOS-DS (n = 2151), and AC-DS (n = 668).

RESULTS

The 2-year cumulative probabilities of dropout were 19% for Milan, 25% for UNOS-DS (P < .001), and 30% for AC-DS (P < .001). In multivariate analysis of the down-staging groups, factors predicting dropout included Model for End-Stage Liver Disease at listing (hazard ratio [HR], 1.06; P < .001) and initial total tumor diameter (HR, 1.04; P = .002). Compared with α-fetoprotein (AFP) level ≤20 ng/mL, AFP levels of 21 to 100, 101 to 1000, and greater than 1000 ng/mL were associated with a higher risk of dropout (HRs, 1.63, 2.06, and 4.58, respectively; P < .001). A subset of all-comers with AFP levels greater than 100 ng/mL had a 2-year probability of dropout of 52% vs 26% for all others beyond Milan criteria (P < .001).

CONCLUSIONS

All-comers had a significantly higher risk for waitlist dropout compared with the UNOS-DS and Milan groups after initial successful down-staging to Milan criteria. In particular, the subgroup of AC-DS with an AFP level greater than 100 ng/mL had a greater than 50% probability of dropout in the next 2 years. These observations suggest a high likelihood of failure when expanding the indications for down-staging.

Organ transplantation using COVID-19-positive deceased donors

The COVID-19 pandemic has influenced organ transplantation decision making. Opinions regarding the utilization of coronavirus disease-2019 (COVID-19) donors are mixed. We hypothesize that COVID-19 infection of deceased solid organ transplant donors does not affect recipient survival. All deceased solid organ transplant donors with COVID-19 testing results from March 15, 2020 to September 30, 2021 were identified in the OPTN database. Donors were matched to recipients and stratified by the COVID-19 test result. Outcomes were assessed between groups. COVID-19 test results were available for 17 694 donors; 150 were positive. A total of 269 organs were transplanted from these donors, including 187 kidneys, 57 livers, 18 hearts, 5 kidney-pancreases, and 2 lungs. The median time from COVID-19 testing to organ recovery was 4 days for positive and 3 days for negative donors. Of these, there were 8 graft failures (3.0%) and 5 deaths (1.9%). Survival of patients receiving grafts from COVID-19-positive donors is equivalent to those receiving grafts from COVID-19-negative donors (30-day patient survival = 99.2% COVID-19 positive; 98.6% COVID-19 negative). Solid organ transplantation using deceased donors with positive COVID-19 results does not negatively affect early patient survival, though little information regarding donor COVID-19 organ involvement is known. While transplantation is feasible, more information regarding COVID-19-positive donor selection is needed.

Organ donation after self-inflicted injury: A single institution analysis

BACKGROUND

This study sought to determine the contribution of self-inflicted injury-related deaths to local organ donation rates and analyze contributing factors.

METHODS

A retrospective review of adult patients with traumatic self-inflicted injuries was performed at a Level I trauma center from 2013 to 2017. Data were obtained from the institutional trauma registry and cross-referenced with the local organ procurement organization (OPO). Referral rates were analyzed and outcomes, demographics and injury characteristics were compared between patients who underwent donation versus those who did not.

RESULTS

142 adult patients presented with traumatic self-inflicted injury, and 100 (70.4%) had referral calls made to the local OPO. These patients were predominantly male (83%), and gunshot injuries accounted for 75% of all mechanisms. Sixty-four percent had organ referrals versus tissue referrals (34%), and 17 (26.6%) of those patients went on to donate. The median number of organs procured was 4 [IQR 0-5]. In multivariate analysis, for each year increase in age, patients were less likely to have an organ referral (OR = .96 [95% CI .93-.99]; p = .0134) and less likely to undergo donation (OR = .95 [95% CI .90-.99]; p = .0308).

CONCLUSIONS

Self-inflicted injury, though tragic, may provide a significant contribution to the limited organ donor registry.

Functional status of heart transplant recipients predicts survival

INTRODUCTION

Recipient functional status prior to transplantation can significantly impact post-transplant survival.

METHODS

The United Network for Organ Sharing database was queried for adult heart transplants including data on functional capacity and from February 1, 2005 to March 1, 2021; there were 32 875 cases included. The four functional categories studied were based on adult daily activities of living and were separated into total assistance required, some assistance required, no assistance required, and near death. Survival outcomes were compared for recipient's pretransplant level of functional status versus those with near death status. These were compared using adjusted logistic regression (odds of death at 30 days and 1 year) and conditional Cox models (overall survival and time until post-transplant rejection). All models were adjusted for donor age, sex, ethnicity, ischemic time, as well as recipient age, sex, ethnicity, length of stay, UNOS region, ventricular assist device, creatinine, days on the waiting list, and status at transplant.

RESULTS

There were 12 953 recipients classified as "near death" or "severely disabled"; 7711 "required total assistance in daily living", 7,328 "needed some", and 4883 "needed none". In adjusted models, the probabilities of death for the lowest functioning groups within 30 days and 1 year were 5% and 10%, respectively. Those "requiring total assistance" had analogous probabilities of 3% (OR = 0.58; p < 0.001) and 9% (OR = 0.81; p < 0.001). Those "requiring some assistance" had probabilities of 3% (OR = 0.56; p < 0.001) and 9% (OR = 0.74; p < 0.001). Lastly, those "requiring no assistance" had probabilities of death of 2% (OR = 0.35; p < 0.001) and 7% (OR = 0.63; p < 0.001).

CONCLUSION

Recipient functional status assessed pre-transplant and recorded in the UNOS database is a strong predictor of post-transplant survival.

Explaining Predictive Model Performance: An Experimental Study of Data Preparation and Model Choice

Although confirmatory modeling has dominated much of applied research in medical, business, and behavioral sciences, modeling large data sets with the goal of accurate prediction has become more widely accepted. The current practice for fitting predictive models is guided by heuristic-based modeling frameworks that lead researchers to make a series of often isolated decisions regarding data preparation and cleaning that may result in substandard predictive performance. In this article, we use an experimental design to evaluate the impact of six factors related to data preparation and model selection (techniques for numerical imputation, categorical imputation, encoding, subsampling for unbalanced data, feature selection, and machine learning algorithm) and their interactions on the predictive accuracy of models applied to a large, publicly available heart transplantation database. Our factorial experiment includes 10,800 models evaluated on 5 independent test partitions of the data. Results confirm that some decisions made early in the modeling process interact with later decisions to affect predictive performance; therefore, the current practice of making these decisions independently can negatively affect predictive outcomes. A key result of this case study is to highlight the need for improved rigor in applied predictive research. By using the scientific method to inform predictive modeling, we can work toward a framework for applied predictive modeling and a standard for reproducibility in predictive research.

Association of donor hypertension and outcomes in orthotopic heart transplantation

The present study examined the impact of donor hypertension on recipient survival and offer acceptance practices in the United States. This was a retrospective study of all patients undergoing OHT from 1995 to 2019 using the United Network for Organ Sharing and Potential Transplant Recipient file databases. Hypertensive donors were stratified by Short (0-5 years) and Prolonged (> 5 years) hypertension. Multivariable logistic regression was used to analyze offer acceptance practices while Cox proportional-hazards models were used to compare mortality across groups. Of 38,338 heart transplants meeting study criteria, 5662 were procured from hypertensive donors (69% Short and 31% Prolonged). After adjustment, Prolonged donor hypertension was associated with increased mortality (hazard ratio, HR, 1.31, 95% confidence interval, CI, 1.04-1.64), while recipients of Short donors experienced no decrement in post-transplant survival. Both Short and Prolonged hypertension were independently associated with decreased odds of offer acceptance (odds ratio, OR .92 95%CI: .88-.96 and OR .93 95%CI: .88-.99, respectively). While prolonged untreated hypertension in OHT donors is associated with a slight decrement in recipient survival, donors with ≤5 years of hypertension yielded similar outcomes. Donor hypertension was associated with reduced organ offer acceptance, highlighting a potential source of organ underutilization.

Changes in waitlist and posttransplant outcomes in patients with adult congenital heart disease after the new heart transplant allocation system

OBJECTIVE

In 2018, the United Network for Organ Sharing (UNOS) introduced new criteria for heart allocation. This study sought to assess the impact of this change on waitlist and posttransplant outcomes in adult congenital heart disease (ACHD) recipients.

METHODS

Between January 2010 and March 2020, we extracted first heart transplant ACHD patients listed from the UNOS database. We compared waitlist and post-transplant outcomes before and after the policy change.

RESULTS

A total of 1206 patients were listed, 951 under the old policy and 255 under the new policy. Prior to transplant, recipients under the new policy era were more likely to be treated with extracorporeal membrane oxygenation (P = .018), and have intra-aortic balloon pumps (P < .001), and less likely to have left ventricular assist devices (P = .027).Compared to patients waitlisted in the pre-policy change era, those waitlisted in the post policy change era were more likely to receive transplants (P = .001) with no significant difference in waiting list mortality (P = .267) or delisting (P = .915). There was no difference in 1-year survival post-transplant between the groups (P = .791).

CONCLUSION

The new policy altered the heart transplant cohort in the ACHD group, allowing them to receive transplants earlier with no changes in early outcomes after heart transplantation.

The 2018 adult heart allocation policy change benefits low-volume transplant centers

INTRODUCTION

The effect of the 2018 adult heart allocation policy change at an institution-level remains unclear. The present study assessed the impact of the policy change by transplant center volume.

METHODS

The United Network for Organ Sharing database was queried for all adults undergoing isolated heart transplantation from November 2016 to September 2020. Era 1 was defined as the period before the policy change and Era 2 afterwards. Hospitals were divided into low-(LVC) medium-(MVC) and high-volume (HVC) tertiles based on annual transplant center volume. Competing-risks regressions were used to determine changes in waitlist death/deterioration, while post-transplant mortality was assessed using multivariable Cox proportional-hazards models.

RESULTS

A total of 3531 (47.0%) patients underwent heart transplantation in Era 1 and 3988 (53.0%) in Era 2. At LVC, Era 2 patients were less likely to experience death/deterioration on the waitlist (subhazard ratio .74, 95% CI .63-.88), while MVC and HVC patients experienced similar waitlist death/deterioration across eras. After adjustment, transplantation in Era 2 was associated with worse 1-year mortality at MVC (hazard ratio, HR, 1.42 95% CI 1.02-1.96) and HVC (HR 1.42, 95% CI 1.02-1.98) but not at LVC.

CONCLUSION

Early analysis shows that LVC may be benefitting under the new allocation scheme.

Post-transplant Diabetes Mellitus in Kidney Transplant Recipients: A Multicenter Study

Background

De novo post-transplant diabetes mellitus (PTDM) is a common complication after kidney transplant (KT). Most recent studies are single center with various approaches to outcome ascertainment.

Methods

In a multicenter longitudinal cohort of 632 nondiabetic adult kidney recipients transplanted in 2010-2013, we ascertained outcomes through detailed chart review at 13 centers. We hypothesized that donor characteristics, such as sex, HCV infection, and kidney donor profile index (KDPI), and recipient characteristics, such as age, race, BMI, and increased HLA mismatches, would affect the development of PTDM among KT recipients. We defined PTDM as hemoglobin A1c ≥6.5%, pharmacological treatment for diabetes, or documentation of diabetes in electronic medical records. We assessed PTDM risk factors and evaluated for an independent time-updated association between PTDM and graft failure using regression.

Results

Mean recipient age was 52±14 years, 59% were male, 49% were Black. Cumulative PTDM incidence 5 years post-KT was 29% (186). Independent baseline PTDM risk factors included older recipient age (P<0.001) and higher BMI (P=0.006). PTDM was not associated with all-cause graft failure (adjusted hazard ratio (aHR), 1.10; 95% CI, 0.78 to 1.55), death-censored graft failure (aHR, 0.85; 95% CI, 0.53 to 1.37), or death (aHR, 1.31; 95% CI, 0.84 to 2.05) at median follow-up of 6 (interquartile range, 4.0-6.9) years post-KT. Induction and maintenance immunosuppression were not different between patients who did and did not develop PTDM.

Conclusions

PTDM occurred commonly, and higher baseline BMI was associated with PTDM. PTDM was not associated with graft failure or mortality during the 6-year follow-up, perhaps due to the short follow-up time.

Greater complexity and monitoring of the new Kidney Allocation System: Implications and unintended consequences of concentric circle kidney allocation on network complexity

The deceased donor kidney allocation system in the United States has undergone several rounds of iterative changes, but these changes were not explicitly designed to address the geographic variation in access to transplantation. The new allocation system, expected to start in December 2020, changes the definition of "local allocation" from the Donation Service Area to 250 nautical mile circles originating from the donor hospital. While other solid organs have adopted a similar approach, the larger number of both kidney transplant centers and transplant candidates is likely to have different consequences. Here, we discuss the incredible increase in complexity in allocation, discuss some of the likely intended and unintended consequences, and propose metrics to monitor the new system.

Outcomes of status 1 liver transplantation for Budd-Chiari Syndrome with fulminant hepatic failure

There is a paucity of data on the outcome of liver transplantation (LT) in Budd-Chiari Syndrome (BCS) patients who are listed as status 1. The objective of our study was to determine patient or graft survival following LT in status 1 BCS patients. We utilized United Network for Organ Sharing (UNOS) database to identify all adult patients (> 18 years of age) listed as status 1 with a primary diagnosis of BCS in the United States from 1998 to 2018, and analyzed their outcomes and compared it to non-status 1 BCS patients. Four hundred and forty-six patients with BCS underwent LT between 1998 and 2018, and of these 55 (12.3%) were listed as status 1. There was no difference in long-term post-liver transplant or "intention-to-treat" survival from the time of listing to death or the last day of follow-up between status 1 and non-status 1 groups. Graft and patient survival at 5 years for status 1 patients were 75% and 82%, respectively. Cox regression analysis showed that patients listed as status 1 (aHR: 0.45, p < .02) were associated with a better survival. BCS patients listed as status 1 have excellent survival following emergency LT.

COVID-19 and transplantation: Fatigue and responsibility

The US transplantation and donation community needs COVID-19–specific information to guide safe and effective transplant care during the pandemic. Goff et al.’s article is on page 2100.

Life underneath the VCA umbrella: Perspectives from the US Uterus Transplant Consortium

The parallel emergence of uterus transplantation (UTx) and other transplantation innovations including face and hand transplantation led to the categorization of the uterus as a vascular composite allograft (VCA). With >60 transplants and >20 births worldwide, UTx is transitioning rapidly from a research endeavor to an effective treatment option for women with uterine factor infertility. While it originally made sense to group the innovations under one umbrella, it is time to revisit the designation of UTx as a VCA. We describe how UTx needs unique policy, procedural codes, insurance contracts, and educational initiatives. We contend that separating UTx from VCAs may become necessary in the future to avoid hindering the growth and regulation of this field.

Defining the roles and responsibilities of the kidney transplant medical director: A necessary step for future training, mentoring, and professional development

The management of a kidney transplant program has evolved significantly in the last decades to become a highly specialized, multidisciplinary standard of care for end-stage kidney disease. Transplant center job descriptions have similarly morphed with increasing responsibilities to address a more complex patient mix, increasing medical and surgical therapeutic options, and increasing regulatory burden in the face of an ever-increasing organ shortage. Within this evolution, the role of the Kidney Transplant Medical Director (KTMD) has expanded beyond the basic requirements described in the United Network for Organ Sharing bylaws. Without a clear job description, transplant nephrology trainees may be inadequately trained and practicing transplant nephrologists may face opaque expectations for the roles and responsibilities of Medical Director. To address this gap and clarify the key areas in which the KTMD interfaces with the kidney transplant program, American Society of Transplantation (AST) formed a Task Force of 14 AST KTMDs to review and define the role of the KTMD in key aspects of administrative, regulatory, budgetary, and educational oversight of a kidney transplant program.

A novel waitlist dropout score for hepatocellular carcinoma - identifying a threshold that predicts worse post-transplant survival

BACKGROUND & AIMS

It has been suggested that patients with hepatocellular carcinoma (HCC) at high risk of wait-list dropout would have done poorly after liver transplantation (LT) because of tumour aggressiveness. To test this hypothesis, we analysed risk of wait-list dropout among patients with HCC in long-wait regions (LWRs) to create a dropout risk score, and applied this score in short (SWRs) and mid-wait regions (MWRs) to evaluate post-LT outcomes. We sought to identify a threshold in dropout risk that predicts worse post-LT outcome.

METHODS

Using the United Network for Organ Sharing database, including all patients with T2 HCC receiving priority listing from 2010 to 2014, a dropout risk score was created from a developmental cohort of 2,092 patients in LWRs, and tested in a validation cohort of 1,735 patients in SWRs and 2,894 patients in MWRs.

RESULTS

On multivariable analysis, 1 tumour (3.1-5 cm) or 2-3 tumours, alpha-fetoprotein (AFP) >20 ng/ml, and increasing Child-Pugh and model for end-stage liver disease-sodium scores significantly predicted wait-list dropout. A dropout risk score using these 4 variables (C-statistic 0.74) was able to stratify 1-year cumulative incidence of dropout from 7.1% with a score ≤7 to 39.5% with a score >23. Patients with a dropout risk score >30 had 5-year post-LT survival of 60.1% vs. 71.8% for those with a score ≤30 (p = 0.004). There were no significant differences in post-LT survival below this threshold.

CONCLUSIONS

This study provided evidence that patients with HCC with the highest dropout risk have aggressive tumour biology that would also result in poor post-LT outcomes when transplanted quickly. Below this threshold risk score of ≤30, priority status for organ allocation could be stratified based on the predicted risks of wait-list dropout without significant differences in post-LT survival.

LAY SUMMARY

Prioritising patients with hepatocellular carcinoma for liver transplant based on risk of wait-list dropout has been considered but may lead to inferior post-transplant survival. In this study of nearly 7,000 patients, we created a threshold dropout risk score based on tumour and liver-related factors beyond which patients with hepatocellular carcinoma will likely have poor post-liver transplant outcomes (60% at 5 years). For patients below this risk score threshold, priority status could be stratified based on the predicted risk of wait-list dropout without compromising post-transplant survival.

Retransplantation outcomes for hepatitis C in the United States before and after direct-acting antiviral introduction

The success of direct-acting antiviral (DAA) therapy has led to near-universal cure for patients chronically infected with hepatitis C virus (HCV) and improved post-liver transplant (LT) outcomes. We investigated the trends and outcomes of retransplantation in HCV and non-HCV patients before and after the introduction of DAA. Adult patients who underwent re-LT were identified in the Organ Procurement and Transplantation Network/United Network for Organ Sharing database. Multiorgan transplants and patients with >2 total LTs were excluded. Two eras were defined: pre-DAA (2009-2012) and post-DAA (2014-2017). A total of 2112 re-LT patients were eligible (HCV: n = 499 pre-DAA and n = 322 post-DAA; non-HCV: n = 547 pre-DAA and n = 744 post-DAA). HCV patients had both improved graft and patient survival after re-LT in the post-DAA era. One-year graft survival was 69.8% pre-DAA and 83.8% post-DAA (P < .001). One-year patient survival was 73.1% pre-DAA and 86.2% post-DAA (P < .001). Graft and patient survival was similar between eras for non-HCV patients. When adjusted, the post-DAA era represented an independent positive predictive factor for graft and patient survival (hazard ratio [HR]: 0.67; P = .005, and HR: 0.65; P = .004) only in HCV patients. The positive post-DAA era effect was observed only in HCV patients with first graft loss due to disease recurrence (HR: 0.31; P = .002, HR 0.32; P = .003, respectively). Among HCV patients, receiving a re-LT in the post-DAA era was associated with improved patient and graft survival.

Liver transplantation for alcoholic hepatitis in the United States: Excellent outcomes with profound temporal and geographic variation in frequency

Medical-refractory severe alcoholic hepatitis (AH) has a high mortality. The national frequency, longer term outcomes and regional practices of AH liver transplantation (LT) in the United States are not well described, despite the increasing mortality from alcohol-associated liver disease. We analyzed the trends in frequency and outcomes of UNOS data on 39 455 adult patients who underwent LT from 2014 to 2019, including AH LT recipients. LTs for AH increased 5-fold, from 28 in 2014 to 138 in 2019, varying 8-fold between UNOS regions. Three transplant centers accounted for 50%-90% of AH LTs within each region. The number of transplant centers performing AH LTs increased from 14 in 2014 to 47 in 2019. AH patients were younger (mean = 39.4 years), had higher MELD scores (mean = 36.8), and were more often on dialysis (46.0%) and in ICU (38.4%), compared to other indications (all P < .05). One- and 5-year graft survivals for AH LT recipients were 91.7% and 81.9%, respectively. The frequency of AH LT is increasing rapidly, with excellent medium-term outcomes. An impact of AH recurrence on patient or graft survival is not apparent in this national analysis. There are marked geographic variations in practices, highlighting the lack of selection criteria standardization.

Transplant center experience influences spontaneous survival and waitlist mortality in acute liver failure: An analysis of the UNOS database

Transplant centers coordinate complex care in acute liver failure (ALF), for which liver transplant (LT) can be lifesaving. We studied associations between waitlist outcomes and center (1) ALF waitlist volume (low: <20; medium: 20-39; high: 40+ listings) and (2) total LT volume (<600, 600-1199, 1200+ LTs) in a retrospective cohort of 3248 adults with ALF listed for LT at 92 centers nationally from 2002 to 2019. Predicted outcome probabilities (LT, died/too sick, spontaneous survival [SS]) were obtained with multinomial regression, and observed-to-expected ratios were calculated. Median center outcome rates were 72.6% LT, 18.2% died/too sick, and 6.1% SS. SS was significantly higher with greater center ALF volume (median 0% for low-, 5.9% for medium-, and 8.6% for high-volume centers; P = .039), while waitlist mortality was highest at low-volume centers (median 21.4%, IQR: 16.1%-26.7%; P = .042). Significant heterogeneity in center performance was observed for waitlist mortality (observed-to-expected ratio range: 0-4.1) and particularly for SS (0-6.4), which persisted despite accounting for recipient case mix. This novel study demonstrates that increased center experience is associated with greater SS and reduced waitlist mortality for ALF. More-focused management pathways are needed to improve ALF outcomes at less-experienced centers and to identify opportunities for improvement at large.

Maximizing donors' gifts: A comparison of actual and expected solid organ yield among VCA donors

Vascularized Composite Allograft (VCA) transplantation provides life-changing transplants, but VCA adds complexity to the donation process and timing, possibly impeding solid organ donation. Expanding upon descriptive analyses, this study examines risk-adjusted predictions versus the observed number of organs donated by VCA donors. Our cohort included VCA donors in the United States during January 1, 2008-December 31, 2017 (n = 51), using OPTN Deceased Donor Registration Form data and the Scientific Registry of Transplant Recipients (SRTR) donor yield models to calculate observed-to-expected (O:E) yield ratios. Almost all VCA donors' livers (48/51; 94.1%) and kidneys (92/102; 90.2%) were transplanted, with fewer hearts (28/51; 54.9%), lungs (46/102; 45.1%), pancreata (15/51; 29.4%), and intestines (3/51; 5.9%) transplanted. O:E ratios for overall organ yield were slightly greater than expected for VCA donors (1.10; 95% CI: 1.02-1.17). Liver (1.17: 1.08-1.27) and lung yields (1.38: 1.07-1.68) were both greater than expected, while kidney, heart, and pancreas yields were similar to expected. Across VCA types, bilateral upper limb and abdominal wall donors had better-than-expected yields while uterus, face, and unilateral upper limb donors all had similar-to-expected yields. Solid organ yield among VCA donors was as good or better than predicted, suggesting that VCA donation does not compromise recovery and transplantation of lifesaving organs.

Statistical performance of 16 posttransplant risk scores in a contemporary cohort of heart transplant recipients

Accurate risk stratification of early heart transplant failure is required to avoid futile transplants and rationalize donor selection. We aimed to evaluate the statistical performance of existing risk scores on a contemporary cohort of heart transplant recipients. After an exhaustive search, we identified 16 relevant risk scores. From the UNOS database, we selected all first noncombined adult heart transplants performed between 2014 and 2017 for validation. The primary endpoint was death or retransplant during the first year posttransplant. For all scores, we analyzed their association with outcomes, sensitivity, specificity, likelihood ratios, and discrimination (concordance index and overlap of individual scores). The cohort included 9396 patients. All scores were significantly associated with the primary outcome (P < .001 for all scores). Their likelihood ratios, both negative and positive, were poor. The discriminative performance of all scores was limited, with concordance index ranging from 0.544 to 0.646 (median 0.594) and an important overlap of individual scores between patients with or without the primary endpoint. Subgroup analyses revealed important variation in discrimination according to donor age, recipient age, and the type of assist device used at transplant. Our findings raise concerns about the use of currently available scores in the clinical field.

Kidney allograft rejection: Diagnosis and treatment practices in USA- A UNOS survey

We studied diverse rejection management strategies across centers by conducting a UNOS survey of kidney transplant program directors in 2017. There were 104 total responses from 235 kidney transplant programs representing 88 unique transplant programs (response rate 37%). Information was collected on center-specific management practices. Pertinent center-specific data were obtained from the OPTN database. Of the respondents, 33% were considered large centers (>100 transplants/year). Thymoglobulin was the most commonly used induction agent at 84%, 72% responders do rapid steroid withdrawal, and mycophenolic acid (MPA) is the major antimetabolite (100%). For diagnosing TCMR, 100% used indication biopsy, 28% used protocol biopsy, 2% used serum biomarkers, and none used urine cytokines. For ABMR, 99% used indication biopsy, 34% used protocol biopsy, 72% used DSA, 21% used C1q positive DSA, and none used gene profiling (ENDATS). The treatment of subclinical and clinical TCMR included iv/PO steroids. PP/IVIG were the commonest treatments for ABMR. The use of rituximab, bortezomib, and eculizumab increased from C4D-ABMR to recurrent ABMR. There are diverse management practices for diagnosing and treating rejection. An effort to harmonize these diverse practices for management of TCMR and ABMR will give an opportunity to pool data for evaluating clinical outcomes.

Stem cell donor HLA typing improves CPRA in kidney allocation

The Organ Procurement and Transplantation Network (OPTN) Kidney Allocation System provides a priority to sensitized candidates based on the calculated panel reactive antibody (CPRA) value. The human leukocyte antigen (HLA) haplotype reference panel used for calculation of the CPRA by the United Network for Organ Sharing (UNOS), the OPTN contractor, has limitations. We derived a novel panel from the National Marrow Donor Program HLA haplotype data set and compared the accuracy of CPRA values generated with this panel (NMDP-CPRA) to those generated from the UNOS panel (UNOS-CPRA), using predicted and actual deceased donor kidney offers for a cohort of 24 282 candidates. The overall accuracy for kidney offers was similar using NMDP-CPRA and UNOS-CPRA. Accuracy was slightly higher for NMDP-CPRA than UNOS-CPRA for candidates in several highly sensitized CPRA categories, with deviations in linkage disequilibrium for Caucasians and the smaller size of the UNOS panel as contributing factors. HLA data derived from stem cell donors yields CPRA values that are comparable to those derived from deceased kidney donors while improving upon several problems with the current reference panel. Consideration should be given to using stem cell donors as the reference panel for calculation of CPRA to improve equity in kidney transplant allocation.

Vascularized composite allotransplantation in the United States: A retrospective analysis of the Organ Procurement and Transplantation Network data after 5 years of the Final Rule

On July 3, 2014, the Organ Procurement and Transplantation Network (OPTN) began overseeing vascularized composite allotransplantation/allografts (VCA) in the United States. For the past 6 years, centers performing VCAs have been requested to submit data into a biometric repository, in parallel with systems used by solid organ transplant centers. Currently, 62 VCAs are reported in the entire OPTN database, with 36 of these transplants reported as performed after VCA was added to the OPTN Final Rule. Of these 36 recipients, 16 received uterus transplants, most of which (11) occurred from living donors. Ten patients received hand transplants and 6 received face transplants. Two patients received abdominal wall transplants, 1 patient received a scalp transplant, and 1 patient received a penile transplant. The present manuscript represents the query of a nationalized database for VCA type, immunosuppression treatment, and clinical outcomes for VCAs. This manuscript provides a report of the current VCA data reported to the OPTN after the Final Rule.

Kidney nonprocurement in solid organ donors in the United States

There are limited data on the nonprocurement of kidneys from solid organ donors. Analysis of Standard Transplant Analysis and Research files was undertaken on all deceased donors in the United States with at least 1 solid organ recovered. From 2000 to 2018, 21 731 deceased donor kidneys (averaging 1144 kidneys per year) were not procured. No kidneys were procured from 8% of liver donors, 3% of heart donors, and 3% of lung donors. Compared to donors with all kidneys procured, those with none procured were older and more likely obese, black, hypertensive, diabetic, hepatitis C positive, smokers, Public Health Service - Increased Risk designated, deceased after cardiac death, or deceased after cerebrovascular accident. Although these donors had lower quality kidneys (median Kidney Donor Risk Index (interquartile range) 1.9 (1.0) vs 1.2 (0.7)), there was substantial overlap in quality between nonprocured and procured kidneys. Nearly one third of nonprocurements were attributed to donor history. Donors with elevated terminal creatinine likely resulting from acute kidney injury (AKI) had higher odds of kidney nonprocurement. Nonprocurement odds varied widely across Organ Procurement and Transplantation Network regions, with a positive correlation between donor kidney nonprocurements and kidney discards at the donation service area level. These findings suggest current discard rates underestimate the underutilization of deceased donor kidneys and more research is needed to optimize safe procurement and utilization of kidneys from donors with AKI.

Third-party vessel allografts in kidney and pancreas transplantation: Utilization, de novo DSAs, and outcomes

Third-party vascular allografts (VAs) are an invaluable resource in kidney and pancreas transplantation when vascular reconstruction is needed and additional vessels from the organ donor are not available. We report the largest single-center experience to date on VA use, at a high-volume U.S. transplant center. Over a 7-year period, VAs were used for vascular reconstruction of 65 kidneys and 5 pancreases, in 69 recipients. The renal vein required reconstruction more often with right kidney transplantation (72.5% vs 27.5%, P < .001), and the renal artery required reconstruction more often with left kidney transplantation (67.6% vs 32.4%, P = .003). Eleven patients (15.9%) developed anti-VA de novo HLA donor-specific antibodies (dnDSAs) at a median time after transplantation of 19.0 months. Higher number of HLA mismatches between the VA donor and the recipient, and development of anti-organ allograft dnDSAs were significant predictors of anti-VA dnDSA development. Those with anti-VA dnDSAs had a higher rate of organ allograft rejection (45.4% vs 13.8%, P = .03) compared to those without, but there was no significant difference in incidence of vascular complications or graft outcomes. VAs can help circumvent challenging surgical situations. Anti-VA dnDSAs do not adversely affect organ allograft outcomes; however, they can contribute to HLA sensitization in the recipients.