United Network Of Organ Sharing Research Articles

ECMO as a bridge to heart transplantation: Insights into stratification by heart failure etiology

PurposeRevisions to the heart allocation criteria in 2018 motivated an increased use of extracorporeal membrane oxygenation (ECMO) as a bridge to transplantation. Studies have demonstrated inferior post-transplant outcomes in patients bridged with ECMO but do not account for underlying diagnosis. Our objective was to elucidate the differential impact of ECMO on outcomes by heart failure (HF) etiology. MethodsThe United Network of Organ Sharing (UNOS) database was queried for adults who underwent isolated heart transplantation after October 2018. Patients were stratified by ECMO utilization at time of transplantation, and then by HF etiology. After baseline statistical comparisons, survival analysis relied on Kaplan-Meier estimates and Cox proportional models. Results13,203 patients were included, of whom 761 (5.8%) were supported with ECMO. ECMO patients were younger (48 vs. 54 years, p<0.001), less likely to have diabetes (24% vs 30%, p<0.001), smoke cigarettes (31% vs 41%, p<0.001) or have prior cardiac surgery (29% vs. 36%, p<0.001), more likely to require dialysis (20% vs. 5%, p<0.001), and spent fewer days on the waitlist (59 vs. 190, p<0.001). After adjustment, ECMO was associated with increased mortality (HR 1.85, p<0.001) in the full cohort. After incorporating HF etiology, this increased mortality risk persisted in all subgroups except restrictive cardiomyopathy and congenital heart disease (CHD). ConclusionsOur findings illustrate that HF etiology is associated with differing outcomes when bridging with ECMO. ECMO patients with restrictive cardiomyopathy or CHD did not have increased mortality risk. With ECMO utilization increasing, these data are hypothesis-generating and serve as a basis for further studies.

The effect of donor–recipient sex matches on lung transplant survival: An analysis of the United Network for Organ Sharing database

ObjectiveTo investigate the impact of donor–recipient (DR) sex matches on survival after lung transplantation while controlling for size difference in the United Network of Organ Sharing (UNOS) database. MethodsWe performed a retrospective study of 27,423 lung transplant recipients who were reported in the UNOS database (January 2005-March 2020). Patients were divided into groups based on their respective DR sex match: male to male (MM), male to female (MF), female to female, (FF), and female to male (FM). Kaplan–Meier curve and Cox regression with log-rank tests were used to assess 1-, 3-, 5-, and 10-year survival. We also modeled survival for each group after controlling for size-related variables via the Cox regression. ResultsKaplan–Meier curves showed overall significance at 1-, 3-, 5-, and 10-year end points (P < .0001). Estimated median survival time based on Kaplan–Meier analysis were 6.41 ± 0.15, 6.13 ± 0.18, 5.86 ± 0.10, and 5.37 ± 0.17 years for FF, MF, MM, and FM, respectively (P < .0001). After we controlled for size differences, FF had statistically significantly longer 5- and 10-year survival than all other cohorts. MF also had statistically significantly longer 5- and 10-year survival than FM. ConclusionsWhen variables associated with size were controlled for, FF had improved survival than other DR groups. A female recipient may experience longer survival with a female donor’s lungs versus a male donor’s lungs of similar size.

Ambulatory Extracorporeal Membrane Oxygenation Use in Patients Listed for Lung Transplant.

There has been an increase in the use of extracorporeal membrane oxygenation (ECMO) to bridge critically ill patients to lung transplant (LTX). This study evaluates how ambulatory status on ECMO affected waitlist and post-LTX outcomes. The United Network of Organ Sharing (UNOS) database was queried for patients aged of greater than or equal to 18 years and between 2016 and 2021 to identify pre-LTX patients supported by ECMO. The patients were classified in venous-arterial (VA) ECMO and veno-venous (VV) ECMO cohorts and further classified as ambulatory (AMB) and non-AMB (nAMB). Each cohort was controlled against the non-ECMO patients. Univariate statistical tests, as well as Kaplan-Meier survival curves, were used for analysis. The 90 day waitlist survival was the highest among the non-ECMO group (96%), but both AMB VV and VA groups had superior survival compared to the nAMB group (85% vs. 75%, 78% vs. 65%, p < 0.01). After adjusting for the median lung allocation score (LAS) (88) in the VV ECMO group, the waitlist survival was superior in the AMB VV ECMO compared to those not on ECMO (86% vs. 78%, p > 0.01). The 1 year post-LTX survival between non-ECMO and AMB VV ECMO was comparable (88% vs. 88%, p = 0.66). Ambulating patients or use of physical therapy while on ECMO can help improve lung transplant outcomes.

Risk Index Predicts Pediatric Heart Allograft Non-Utilization.

Children listed for heart transplantation face the highest waitlist mortality among all solid organ transplant patients (14%). Attempts at decreasing donor allograft non-utilization (41.5%) could potentially decrease waitlist mortality for pediatric heart transplant patients. Our aim was to quantify the non-utilization risk of pediatric donor heart allografts at the time of initial offering. Using the United Network of Organ Sharing (UNOS) database, we retrospectively analyzed 8823 deceased donors (≤18 years old) data through univariable and multivariable analysis and logistic regression models. These factors were divided into a training (n = 5882) and validation set (n = 2941). Donor clinical characteristics and laboratory values were used to predict non-utilization of donor hearts. The multivariable analysis used factors that were significant from the univariable analysis (p-value < .05), and the pediatric non-utilization risk index (pDRSI) included significant factors from the multivariable analysis, producing an overall risk score for non-utilization. With these data, we created a non-utilization risk index to predict likelihood of donor allograft non-utilization. From the 24 potential factors that were identified from univariable analysis, 17 were significant predictors (p < .05) of pediatric heart non-utilization in the multivariable analysis. Low left ventricular ejection fraction (odds ratio (OR)-35.3), hepatitis C positive donor (OR-23.3), high left ventricular ejection fraction (OR-3.29), and hepatitis B positive donor (OR-3.27) were the most significant risk factors. The phDSRI has a C-statistic of 0.80 for the training set and 0.80 for the validation set. Using over 8000 donors, the phDSRI uses 17 significant risk factors to predict risk of pediatric heart donor allograft non-utilization.

Waitlist and posttransplant outcomes of pregnancy-related acute liver failure in the United States.

Data on the liver transplant (LT) outcomes of women with acute liver failure (ALF) due to liver diseases unique to pregnancy (P-ALF) are limited. Using United Network of Organ Sharing (UNOS) data (1987-2021), we analyzed waitlist and post-LT outcomes of ALF in women of childbearing age comparing P-ALF versus ALF due to liver diseases not unique to pregnancy. Baseline characteristics were compared between groups at the time of listing for LT. Of 3542 females aged 16-43 years and listed for LT for ALF, 84 (2%) listed for P-ALF were less likely to be Black (11 vs. 21%, p =0.033), have lower international normalized ratio (2.74 vs. 4.53 p <0.002), but more likely to have respiratory failure (56% vs. 41%, p <0.005), be on pressors (58% vs. 43%, p <0.005), and require dialysis (23% vs. 10%, p <0.001). The cumulative 90-day waitlist mortality (WLM) was lower in P-ALF vs. ALF due to liver diseases not unique to pregnancy (7.4 vs. 16.6%, p <0.001). Posttransplant survival rates at 5 years were similar (82% vs. 79%, p =0.89). In a Fine and Gray regression model controlled for listing year and Model for End-Stage Liver Disease score, 90-day WLM was lower in P-ALF with a sub-HR of 0.42 (95% CI: 0.19-0.94, p =0.035). Of 84 women with P-ALF and listed for LT, 45 listed for hemolysis-elevated liver enzymes-low platelets (HELLP) versus 39 for acute fatty liver of pregnancy had higher 90-day WLM (19.3% vs. 5.7% p <0.005). The 90-day WLM was about 10-fold higher in HELLP versus acute fatty liver of pregnancy with a sub-HR of 9.97 (95% CI: 1.64-60.55, p =0.013). In this UNOS database analysis of ALF among women of childbearing age, the waitlist outcome is better in women with P-ALF compared to women with ALF due to liver diseases not unique to pregnancy. Among women with P-ALF, the 90-day WLM is worse for HELLP versus acute fatty liver of pregnancy. Further studies are needed to improve the management of HELLP and prevent the development of ALF in this subgroup population.

Post-transplant survival with pre-transplant durable continuous-flow mechanical circulatory support in a Swiss cohort of heart transplant recipients.

Worldwide, almost half of all heart transplantation candidates arrive today at their transplant operation with durable continuous-flow mechanical circulatory support (CF-MCS). This evolution is due to a progressive increase of waiting list time and hence an increased risk of haemodynamic worsening. Longer duration of CF-MCS is associated with a higher risk of device-related complications with potential adverse impact on post-transplant outcome as suggested by recent results from the United Network of Organ Sharing of the United States. A 2-centre Swiss heart transplantation programme conducted a retrospective observational study of consecutive patients of theirs who underwent a transplant in the period 2008-2020. The primary aim was to determine whether post-transplant all-cause mortality is different between heart transplant recipients without or with pre-transplant CF-MCS. The secondary outcome was the acute cellular rejection score within the first year post-transplant. The study participants had a median age of 54 years; 38/158 (24%) were females. 53/158 study participants (34%) had pre-transplant CF-MCS with a median treatment duration of 280 days. In heart transplant recipients with pre-transplant CF-MCS, the prevalence of ischaemic cardiomyopathy was higher (51 vs 32%; p = 0.013), the left ventricular ejection fraction was lower (20 vs 25; p = 0.047) and pulmonary vascular resistance was higher (2.3 vs 2.1 Wood Units; p = 0.047). Over the study period, the proportion of heart transplant recipients with pre-transplant CF-MCS and the duration of pre-transplant CF-MCS treatment increased (2008-2014 vs 2015-2020: 22% vs 45%, p = 0.009; increase of treatment days per year: 34.4 ± 11.2 days, p = 0.003; respectively). The primary and secondary outcomes were not different between heart transplant recipients with pre-transplant CF-MCS or direct heart transplantation (log-rank p = 0.515; 0.16 vs 0.14, respectively; p = 0.81). This data indicates that the strategy of pre-transplant CF-MCS with subsequent orthotopic heart transplantation provides post-transplant outcomes not different to direct heart transplantation despite the fact that the duration of pre-transplant assist device treatment has progressively increased.

Improved outcomes of kidney after liver transplantation after the implementation of the safety net policy.

The number of kidney after liver transplants (KALT) increased after the implementation of the United Network of Organ Sharing (UNOS) safety net policy, but the effects of the policy on KALT outcomes remain unknown. Using the UNOS database, we identified KALT between 60 and 365 days from liver transplant from January 1, 2010, to December 31, 2020. The main outcome was 1- and 3-year patient, liver, and kidney graft survival. Secondary outcomes included 6-month and 1-year acute rejection (AR) of liver and kidney, and 1-year kidney allograft function. Of the 256 KALT, 90 were pre-policy and 166 post-policy. Compared to pre-policy, post-policy 1- and 3-year liver graft survival was higher (54% and 54% vs. 86% and 81%, respectively, p <0.001), while 1- and 3-year kidney graft survival (99% and 75% vs. 92% and 79%, respectively, p =0.19), and 1- and 3-year patient survival (99% and 99% vs. 95% and 89%, respectively, p =0.11) were not significantly different. Subgroup analysis revealed similar trends in patients with and without renal failure at liver transplant. Liver AR at 6 months was lower post-policy (6.3% vs. 18.3%, p =0.006) but was similar (10.5% vs. 13%, p =0.63) at 1 year. Kidney AR was unchanged post-policy at 6 months and 1 year. Creatinine at 1 year did not differ post-policy versus pre-policy (1.4 vs. 1.3mg/dL, p =0.07) despite a higher proportion of deceased donors, higher Kidney Donor Profile Index, and longer kidney cold ischemia time post-policy ( p <0.05 for all). This 3-year follow-up after the 2017 UNOS policy revision demonstrated that the safety net implementation has resulted in improved liver outcomes for patients who underwent KALT with no increased AR of the liver or the kidney allografts.

Abstract 15491: Have Heart Transplant Allocation Policy Changes Brought Improvements in Mortality for Children and Adults With Congenital Heart Disease? A UNOS Database Analysis

Introduction: The United Network of Organ Sharing (UNOS) made changes to the priority for allocation of hearts for transplantation (HT) in 2016 for pediatric patients and 2018 for adult patients. There are limited data describing the association of these changes with waitlist outcomes in patients with congenital heart disease (CHD). Methods: The United Network for Organ Sharing (UNOS) database was queried for pediatric (&lt;18 y/o, PCHD), and adult (18yo-50yo, ACHD), patients with a CHD diagnosis listed for HT. Cohorts were grouped into pre and post-allocation change eras: PCHD 1/1/11-3/21/15 and 1/1/17-12/31/21, ACHD 1/1/15-10/17/18 and 1/1/19 to 12/31/21. Differences in era for survival from the time of listing for HT were compared using competing risk models. Results: We identified 3,646 patients listed for HT during the study period including 1,520 PCHD and 432 ACHD pre-allocation change and 1,443 and 251 post. More PCHD patients in the post cohort were supported with ventricular assist devices (7.6% vs 3.2%) while fewer were on inotropes (41% vs 47%), intubated (18% vs 21%) or on ECMO (5.3% vs 7.9%) (p for all &lt;0.01 ). For ACHD, ECMO (4.8% vs 1.9%) and intra-aortic balloon pump (6.8% vs 1.9%) use was more prevalent in the post era (p&lt;0.05 for both). In a competing risk model adjusting for illness severity, the HR for death or waitlist removal within 1 year of HT listing was higher in the pre-allocation era compared to post for PCHD (HR 1.27 [95% CI 1.06-1.52]) but unchanged for ACHD (HR 1.36 [95% CI 0.77-2.41]). Figure 1 Conclusions: ACHD patients did not have the mortality benefit from policy changes which other groups, including PCHD, have experienced. Incorporating measures into the allocation system which more completely capture the illness severity that comes with ACHD are warranted, as are strategies to improve long term survival in this growing population.

Abstract 15264: Impact of 2018 Change in UNOS Heart Transplant Policy on Wait List Outcomes

Introduction: In October 2018, the updated Heart transplant (HT) policy by United network of Organ Sharing (UNOS) gave priority to critically ill heart failure patients. It has made significant improvement in long term survival of ECMO bridged HT recipients. However, there are limited reports on wait list mortality following change in this policy. Hypothesis: Review of waitlist mortality following 2018 change in guideline Methods: This is a retrospective cohort study including all adult heart failure patients listed for HT alone between 2015 and 2022 in the UNOS data. Cohort was stratified on the basis of year of listing, those who listed between 2015 &amp; 2018 and those who listed between 2019 &amp; 2022. The categorical and continuous variables were compared using chi2 and Kruskal Wallis test, respectively. Time to death analysis between both the group was evaluated using Kaplan Meier curve and log rank test. Results: Total 33,908 patients were included, of them 16,281 were listed between 2015 &amp; 2018 and remaining 17,627 were listed between 2019 &amp; 2022. The rate of HT did not change between both the time period (10,660 (65.5%) &amp; 11,660 (66.1%), p=0.19)), respectively. There was no difference in age, gender and BMI between both the groups. The use of Intra-aortic balloon pump, ventilator, Inotropes and other parameters indicating severity of illness were frequently noted among patients listed between 2019 &amp; 2022. The overall wait list mortality has reduced from 1250/16,281(7.7%) to 764/17,627 (4.0%) during later time period, p&lt;0.001 (Figure 1). Similarly, patients’ dropouts due to illness severity has reduced from 1321/16821 (8.1%) to 764/17,627 (4.3%), p&lt;0.001, respectively. There is significant reduction in disease etiology specific mortality following 2018 change. Conclusions: The change in HT policy in 2018 has significantly reduced the wait list mortality and dropouts during study periods. In addition, sicker patients were listed for transplant following 2018 change.

Outcomes of Combined Heart-Kidney Transplantation in Older Recipients.

The upper limit of recipient age for combined heart-kidney transplantation (HKT) remains controversial. This study evaluated the outcomes of HKT in patients aged ≥65 years. The United Network of Organ Sharing (UNOS) was used to identify patients undergoing HKT from 2005 to 2021. Patients were stratified by age at transplantation: <65 and ≥ 65 years. The primary outcome was one-year mortality. Secondary outcomes included 90-day and 5-year mortality, postoperative new-onset dialysis, postoperative stroke, acute rejection prior to discharge, and rejection within one-year of HKT. Survival was compared using Kaplan-Meier analysis, and risk adjustment for mortality was performed using Cox proportional hazards modeling. HKT in recipients aged ≥65 significantly increased from 5.6% of all recipients in 2005 to 23.7% in 2021 (p=0.002). Of 2,022 HKT patients in the study period, 372 (18.40%) were aged ≥65. Older recipients were more likely to be male and white, and fewer required dialysis prior to HKT. There were no differences between cohorts in unadjusted 90-day, 1-year, or 5-year survival in Kaplan-Meier analysis. These findings persisted after risk-adjustment, with an adjusted hazard for one-year mortality for age ≥65 of 0.91 (95% CI (0.63-1.29), p=0.572). As a continuous variable, increasing age was not associated with one-year mortality (HR 1.01 (95% CI (1.00-1.02), p=0.236) per year). Patients aged ≥65 more frequently required new-onset dialysis prior to discharge (11.56% vs. 7.82%, p=0.051). Stroke and rejection rates were comparable. Combined HKT is increasing in older recipients, and advanced age ≥65 should not preclude HKT.

Can ex-situ normothermic perfusion improve graft survival compared to static cold storage among donation after circulatory death liver allografts?

Limited data suggest that ex-situ normothermic liver perfusion (ENLP) may improve the outcomes of donation after circulatory death (DCD) liver transplants compared to static cold storage (SCS). All adult DCD liver transplants performed between 2016 and 2021 were identified in the United Network of Organ Sharing database. ENLP liver transplants were compared to SCS using inverse probability of treatment weighting to balance clinical and demographic confounders. The primary analysis simulated intention-to-treat with inverse probability of treatment weighting-adjusted Cox models. Compared to SCS DCDs (N = 3,079), recipients of ENLP DCDs (N = 65) had lower Model of End Stage Liver Disease scores at transplant (16.5 v. 18.8, p = 0.033), longer wait times (468 ± 720 vs. 246 ± 467d; p < 0.001), and received livers from donors with a greater BMI (29.2 vs. 27.5; p = 0.008). ENLP preservation was associated with a lower risk of graft failure (HR 0.31 vs. SCS, 95% CI:0.12-0.86, p = 0.023) and a lower incidence of retransplantation. A sub-analysis restricted to the 20 centers performing ENLP, encompassing 946 SCS DCDs, demonstrated similar results: (HR 0.33 vs. SCS, 95% CI: 0.13-0.94, p = 0.021). Among 111 patients who required retransplantation and where the etiology of graft failure was identified, graft failure due to ischemic cholangiopathy was noted in 1 ENLP and 46 SCS. In this retrospective analysis of the early US DCD ENLP experience, there may exist a graft survival benefit to transplants performed with ENLP compared to SCS.

An Efficient Allocation for Lung Transplantation Using Ant Colony Optimization

A relationship between lung transplant success and many features of recipients’/donors has long been studied. However, modeling a robust model of a potential impact on organ transplant success has proved challenging. In this study, a hybrid feature selection model was developed based on ant colony optimization (ACO) and k-nearest neighbor (kNN) classifier to investigate the relationship between the most defining features of recipients/donors and lung transplant success using data from the United Network of Organ Sharing (UNOS). The proposed ACO-kNN approach explores the features space to identify the representative attributes and classify patients’ functional status (i.e., quality of life) after lung transplantation. The efficacy of the proposed model was verified using 3,684 records and 118 input features from the UNOS. The developed approach examined the reliability and validity of the lung allocation process. The results are promising regarding accuracy prediction to be 91.3% and low computational time, along with better decision capabilities, emphasizing the potential for automatic classification of the lung and other organs allocation processes. In addition, the proposed model recommends a new perspective on how medical experts and clinicians respond to uncertain and challenging lung allocation strategies. Having such ACO-kNN model, a medical professional can summarize information through the proposed method and make decisions for the upcoming transplants to allocate the donor organ.

Prognostic implications of inactive status in highest urgency categories among heart transplantation recipients in the new donor heart allocation system.

Patients on the waiting list for heart transplantation (HT) can become inactive or made status seven because of medical reasons, such adverse events, complications, or psychosocial circumstances. If the condition that caused the inactivation is resolved, patients are re- activated. Information about the prognostic implications of Status 7 in the new donor heart allocation system has not been described. To bridge this knowledge gap, we performed an analysis of the United Network of Organ Sharing (UNOS) registry. Data on adult patients who underwent HT between October 18th, 2018 and October 2021, were queried from the UNOS registry. The main outcomes were post- transplant all-cause mortality, 1-year all-cause mortality and treated acute rejection. Since re-transplantation is a competing event for all-cause mortality, we performed competing risk survival analysis and reported sub distribution hazard ratios (SHR) from the Fine and Gray model to examine the relationship between inactive status and all-cause mortality. A total of 5267 adult patients underwent HT and were previously listed as Status 1 or Status 2 in the new allocation system. We identified 946 HT recipients temporarily inactivated while on HT list (18%). The number of temporarily inactive patients remained stable since the implementation of the new donor allocation system (p=.37). Approximately, two-thirds of temporarily inactive patients (65.9%) were inactivated for being too sick, whereas other frequent justifications for inactivity included left ventricular assist device implantation (7.8%) and insurance related issues (4.8%). Temporarily inactive HT recipients were more likely to be African Americans, males, have a higher body mass index (BMI) and significantly longer waiting time (391.6±600vs. 72.3±223 days, p<.001) compared with never inactivated patients. In the unadjusted analyses 30-day mortality did not differ between groups, but both 1-year and overall all-cause mortality was significantly higher in temporarily inactive patients (1-year: SHR: 1.3; 95% confidence intervals [CI]: 1.03, 1.64; p=.028, overall mortality SHR: 1.31; 95% CI: 1.06, 1.64; p=.014). After adjustment for donor and recipient characteristics, a trend towards higher 1-year and overall mortality remained (1-year: SHR 1.32; 95% CI .99, 1.76, p=.006, overall mortality SHR: 1.29; 95% CI: .98-1.68, p=.065). No differences in treated acute allograft rejection at 1 year were found between groups. Temporary inactive status while waiting for HT occurs in approximately one in five HT recipients listed in higher urgency categories after the implementation of the new allocation system. A signal of adverse long-term outcomes was found, and this could be explained by differences in recipient characteristics. Further research is required to elucidate pathways involved and possible implications for clinical practice.

The impact of the United Network of Organ Sharing allocation change on waitlist trajectories of inpatients listed with inotropic support: A single-center analysis.

In the United Network of Organ Sharing (UNOS) allocation scheme prior to October 18, 2018, heart transplant (HTx) candidates with extracorporeal membrane oxygenation (ECMO), temporary mechanical circulatory support (MCS), or pulmonary artery (PA) catheter inotropic support all received Status 1A priority. In revised scheme, patients with PA catheter and inotropic support are Status 3 after those on ECMO (Status 1) or temporary MCS (Status 2). We examined the impact of the allocation change on HTx candidates listed Status 1A versus Status 3 at a high-volume transplant center. Between January 2017 and January 2021, 75 patients were listed with a PA catheter and inotropic support prior to the allocation change (Era 1) and 48 were listed after (Era 2). Clinical characteristics and outcomes were compared for these 123 patients. Heart transplant (HTx) candidates in Era 2 had higher median inotrope doses at listing. There was no significant difference in inpatient wait list days (12vs. 20 days, P=.15), transition to temporary MCS (33.3%vs. 22.7%, P=.15), or wait list mortality (6.3%vs. 4.0%, P=.68). There was also no significant difference in survival to transplantation (91.7%vs. 94.7%, P=.71). There were no differences in post-transplant outcomes including 1-year survival (88.6%vs. 93.0%, P=.38). At a high-volume transplant center, the UNOS allocation change did not result in increased wait list time, use of temporary MCS, or mortality on the waitlist or post-transplant for candidates on inotropic support with continuous hemodynamic monitoring.

Predictors of renal recovery in recipients of liver transplant alone who met 2017 simultaneous liver-kidney transplant criteria.

Severe renal dysfunction is common among liver transplant (LT) candidates and often prompts simultaneous liver-kidney transplantation (SLKT) consideration. In view of 2017 United Network of Organ Sharing (UNOS) criteria for SLKT, we investigated the likelihood and predictors of renal recovery among patients who met the aforementioned criteria yet received liver transplant alone (LTA). We retrospectively analyzed relative renal recovery (RRR; increase in eGFR to >30ml/min) in adult LTA recipients between 1/2009 and 1/2019. Of 1165 LT recipients, 54 met 2017 UNOS criteria, with 37 receiving LTA. RRR occurred in 84% of LTA recipients, none of whom had pre-LT eGFR <20ml/min. Sustained RRR (>180 days) occurred in 43% of patients. While prolonged pre-LT severe renal impairment (eGFR <30 ml/min) predicted failure to have sustained RRR (HR .19 per 90-day, CI .04-.87, p<.005), having an eGFR measurement of >30ml/min within 90 days pre-LT (HR 5.52, CI 1.23-24.79, p .01) associated with achieving sustained RRR. Sustained RRR was protective againstthe composite outcome of renal replacement therapy, kidney transplant, and death (HR .21, p .01). LT candidates who meet 2017 UNOS criteria for SLKT yet undergo LTA can still have relative renal recovery post-LT, exceeding 80% on short-term follow-up and 40% on long-term follow-up. eGFR trends within 90 days pre-LT can predict sustained renal recovery, which appears protective of adverse outcomes. These recovery rates advocate for applying the more restrictive criteria for SLKT outlined in this article and increasing utilization of the safety net (SN) policy for those who do not meet the proposed criteria.

Characteristics and outcomes of left ventricular assist device recipients transplanted before and after the new donor heart allocation system

Abstract Background Concerns about the impact of the new donor heart allocation system on post-transplant outcomes have emerged after its implementation. We sought to evaluate the characteristics and outcomes of left ventricular assist device (LVAD) recipients transplanted before and after the implantation of the new policy on October 18, 2018. Methods Data on bridge to transplantation adult LVAD patients January 2015 and October 2021, with durable LVAD as a (BTT), was queried from the United Network of Organ Sharing (UNOS) registry. The main outcomes were 30-day all-cause mortality, 30-day fatal graft failure, 1-year all-cause mortality, treated acute rejection at one year and renal replacement therapy (RRT) for acute renal failure. Results In our study, 7096 patients met the inclusion criteria including 2,435 in the new allocation system. The transplanted patients in the new allocation system era had older donor age, longer ischemic time and higher proportion of newer generation LVADs. Adjusted 30-day all-cause mortality was significantly lower for LVAD recipients in the new allocation system era (sub-hazard ratio [SHR] 0.36, 95% Confidence intervals [CI] 0.27–0.48, p&amp;lt;0.001) without differences in the risk of fatal graft failure and one-year mortality. Significantly lower adjusted 30-day mortality with HVAD and HM3 devices than HM2 in the new allocation system era was found, without differences in one-year mortality. Acute allograft rejection requiring treatment was significantly lower (Odds Ratio 0.78, 95% CI 0.65–0.94, p=0.01) whereas a trend towards higher risk of renal failure requiring RRT was identified. Conclusions Despite changing donor characteristics and longer ischemic times, post-transplant outcomes in LVAD recipients have not worsened with the implementation of the new allocation system and this finding is related to the use of newer generation continuous flow LVADs. Funding Acknowledgement Type of funding sources: None.

Gender mismatch and outcomes following heart transplantation in the United States

Abstract Background Available literature indicates the possible detrimental effect of gender mismatching on mortality in patients undergoing heart transplantion. Our objective was to examine the role of gender mismatching on mortality and graft rejection in patients undergoing heart transplantation in the US. Methods Data on adult patients January who underwent heart transplantation between January 2015 and October 2021, was queried from the United Network of Organ Sharing (UNOS) registry. The main outcomes were all-cause mortality, 1-year all-cause mortality and treated acute rejection. Results A total of 19,805 adult patients underwent heart transplant during the study period. Approximately, one out of ten patients in the M-F group had a PHM mismatch&amp;lt;25%, while only four out of ten patients had such a mismatch in the F-M group. In both M-M and F-F groups, seven out of ten patients had a PHM mismatch&amp;lt;25% (p=0.122). Proportion of PHM mismatch was similar throughout the study period. Unadjusted analysis showed that M-F was associated with increased risk for all-cause mortality (HR: 1.13; 95% CI: 1.02, 1.27; p=0.026) and 1-year mortality (HR: 1.26; 95% CI: 1.09, 1.45; p=0.002) compared to M-M. Graft failure incidence was higher in the M-F group compared to M-M (HR: 1.12; 95% CI: 1.01, 1.25; p=0.041). Conclusions Gender mismatching is associated with post-transplant mortality with transplantation of female donor grafts to male recipients demonstrating worse outcomes. Further research is required to elucidate pathways involved and possible changes in clinical practice. Funding Acknowledgement Type of funding sources: None.

Sex mismatch following heart transplantation in the United States: Characteristics and impact on outcomes.

Available literature indicates the possible detrimental effect of sex mismatching on mortality in patients undergoing heart transplantation. Our objective was to examine the role of sex and heart mass (predicted heart mass [PHM]) mismatch on mortality and graft rejection in patients undergoing heart transplantation in the US. Data on adult patients who underwent heart transplantation between January 2015 and October 2021 were queried from the United Network of Organ Sharing (UNOS) registry. The main outcomes were all-cause mortality, 1-year all-cause mortality and treated acute rejection. A total of 19805 adult patients underwent heart transplant during the study period. 92.2% of the patients in the female graft to male group had a PHM mismatch <25%, while only 38.5% had such a mismatch in the male graft to female group. In male to male and female to female groups, 79% and 76% of the patients had a PHM mismatch <25% (p=.122). Proportion of PHM mismatch was similar throughout the study period. Unadjusted analysis showed that male recipients of female grafts had increased risk for all-cause mortality (hazard ratio [HR]: 1.13; 95% confidence intervals [CI]: 1.02, 1.27; p=.026) and 1-year mortality (HR: 1.26; 95% CI: 1.09, 1.45; p=.002) compared to male recipients of male grafts. Graft failure incidence was also higher (HR: 1.12; 95% CI: 1.01, 1.25; p=.041). However, all these associations were non- significant after risk factor adjustment. Sex mismatching is associated with post-transplant mortality with transplantation of female donor grafts to male recipients demonstrating worse outcomes, although this association disappears after risk factor adjustment. Further research is required to elucidate the need for potential changes in clinical practice.

335.6: Long-term Outcomes of Living Donor Versus Deceased Donor Liver Transplantation for Acute Liver Failure in United States

Introduction: Acute Liver Failure (ALF) is rarely encountered but often is associated with high morbidity and mortality. Timely Liver Transplantation is universally the only accepted rescue therapy, but not much is known about the usage of Living Donor (LDLT) versus Deceased Donor (DDLT)Liver Transplantation in the United States for this indication. Method: United Network of Organ Sharing/ Organ Procurement and Transplantation Network (UNOS/OPTN) data was reviewed from January 2002 to December 2020. Adult and pediatric recipients with diagnostic codes for ALF and listed as Status 1 were included in the study. Clinical, laboratory, and demographic characteristics were compared between LDLT and DDLT groups. In addition, Post-transplant survival rates were compared between the two groups. Results: There were a total of 246 LDLT (3.8%) and 6153 DDLT (96.2%) recipients with the diagnosis of ALF (Table 1). There was a difference in age and gender between the groups, with 93.5% of LDLT cases being for pediatric ALF cases versus 45.9% of DDLT cases being for pediatric recipients of age less than 18. There were more female gender in the DDLT group. Race was not different between the two groups. The proportion of patients waiting ≥ 3 days was 64.1% in DDLT compared to 77.2% in the LDLT group (P<0.001). There was no statistical difference between the two groups in terms of sodium, bilirubin, and INR. There were more patients with hepatic encephalopathy, and on renal replacement therapy in the DDLT group compared to LDLT group. Overall, 1, 5 and 10 year overall survival among the DDLT and LDLT groups were also similar, 87.7% vs. 85.5%, 81.1% vs. 81.1%, 74.7% vs. 79.3% (p=0.16) (Figure 1) (Log rank P=0.16). Conclusions: In the US, LDLT constitutes of only 3.8% of all liver transplants for ALF. In addition, LDLT was mostly used among pediatric recipients (93.5%), whereas DDLT was mostly used for adult recipients (54.1%). Signs of decompensation with hepatic encephlopathy, ascites, and on renal replacement therapy were more common in DDLT than LDLT group. LDLT can be carefully considered in a select group of adult ALF cases, in early phases, before further progression into renal failure and advanced encephalopathy.

Lung Transplantation for COVID-19-related Lung Disease: Clinical Experience and Call for a Global Registry.

Lung Transplantation for COVID-19-related Lung Disease: Clinical Experience and Call for a Global Registry.