Changes In Allocation Policy Research Articles

Impact of post-transplant stroke and subsequent functional independence on outcomes following heart transplantation under the 2018 United States heart allocation system

This study evaluates the clinical trends, risk factors, and effects of post-transplant stroke and subsequent functional independence on outcomes following orthotopic heart transplantation under the 2018 heart allocation system. The United Network for Organ Sharing registry was queried to identify adult recipients from October 18, 2018 to December 31, 2021. The cohort was stratified into 2 groups with and without post-transplant stroke. The incidence of post-transplant stroke was compared before and after the allocation policy change. Outcomes included post-transplant survival and complications. Multivariable logistic regression was performed to identify risk factors for post-transplant stroke. Sub-analysis was performed to evaluate the impact of functional independence among recipients with post-transplant stroke. A total of 9,039 recipients were analyzed in this study. The incidence of post-transplant stroke was higher following the policy change (3.8% vs 3.1%, p=0.017). Thirty-day (81.4% vs 97.7%) and 1-year (66.4% vs 92.5%) survival rates were substantially lower in the stroke cohort (p<0.001). The stroke cohort had a higher rate of post-transplant renal failure, longer hospital length of stay, and worse functional status. Multivariable analysis identified extracorporeal membrane oxygenation, durable left ventricular assist device, blood type O, and redo heart transplantation as strong predictors of post-transplant stroke. Preserved functional independence considerably improved 30-day (99.2% vs 61.2%) and 1-year (97.7% vs 47.4%) survival rates among the recipients with post-transplant stroke (p<0.001). There is a higher incidence of post-transplant stroke under the 2018 allocation system, and it is associated with significantly worse post-transplant outcomes. However, post-transplant stroke recipients with preserved functional independence have improved survival, similar to those without post-transplant stroke.

Duration of Bridge-to-Transplant Extracorporeal Membrane Oxygenation and Heart Transplant Survival

Background. The 2018 Organ Procurement and Transplantation Network (OPTN) heart allocation policy change prioritizes patients bridged to transplant with mechanical circulatory support (MCS) devices, including extracorporeal membrane oxygenation (ECMO). As a result, the use of ECMO has significantly increased. Methods. We reviewed the OPTN database for adult patients undergoing heart transplant after bridge with ECMO between January 1st 2000 and October 18th 2018. We excluded patients with ≥180 days of ECMO duration, prior transplants, and those using additional MCS devices. Survival and morbidity outcomes of patients with ≥7 days of pre-transplant ECMO were compared to those of patients with &lt;7 days. Results. Of 362 eligible transplant recipients, 163 (45%) utilized &lt;7 days of pre-transplant ECMO and 199 (55%) utilized ≥7 days. Those with ≥7 days were younger (median age: 43 [28–54] vs. 50 [36–57] years, p=0.006) and more likely to have temporary waitlist inactivity (18% vs. 7%, p=0.003) with significantly longer duration of ECMO use (median: 14 [9–24] vs. 4 [2–5] days, p &lt; 0.001). Patients with ≥7 days of ECMO had comparable survival to those with &lt;7 days at one year (81.1% vs. 79.4%, p=0.64) and five years (61.1% vs. 49.3%, p=0.27). After adjustment for clinically relevant variables, duration of ECMO ≥7 days did not increase mortality at five years (HR = 0.90, p=0.59). Conclusions. Longer duration of ECMO (≥7 days vs. &lt;7 days) among patients successfully bridged to transplant is not associated with increased mortality or selected adverse outcome, including graft failure or rejection, at up to five years.

Abstract 13723: Waitlist Outcomes for Pediatric Heart Transplantation in the Current Era: An Analysis of the PHTS Database

Introduction: Waitlist mortality (WM) remains high in pediatric heart transplantation (HT). Allocation policy is a potential tool to help improve WM. This study aims to identify patients listed status 1A at highest risk for WM to potentially inform future allocation policy changes. Hypothesis: Significant variation in WM will exist even within highest urgency waiting status (1A). Methods: The pediatric heart transplant society database was queried for all patients &lt;18 years of age listed for HT between January 1, 2010 to December 31, 2021. WM was defined by death while awaiting transplant or being removed from the waitlist due to clinical deterioration. Kaplan-Meier analysis, log-rank testing, and Cox-proportional hazard models were created to determine association with WM. Subgroup analysis was performed in 1A patients based upon body surface area (BSA) at time of listing, cardiac diagnosis, and presence of mechanical circulatory support. Results: Among 5,974 children listed, 3928 (65.8%) were status 1A. Patients listed 1A had a higher burden of WM (p&lt;0.01) compared to patients listed status 1B or status 2. Among 1A patients, BSA&lt;0.3m 2 , congenital heart disease (CHD), and lower eGFR was associated with higher WM. VAD support at listing was associated with lower WM (figure, all p-values&lt;0.01) except in the single ventricle cohort (CHD-SV) (HR 2.13, p&lt;0.01). For BSA&lt;0.3m 2 listings, diagnosis other than dilated cardiomyopathy was associated with increased risk of WM . Prior cardiac surgery was associated with WM in the BSA 0.3-0.7m 2 and &gt;0.7m 2 groups. ECMO was associated with increased risk of WM in all cohorts (HR 2.26, p&lt;0.01). Conclusions: Significant variability exists in WM in patients listed 1A. Future changes to the pediatric allocation system should factor in the increased risk of WM in patients supported by ECMO, CHD-SV on VAD support, and small children with CHD, RCM or HCM.

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.

P8.2: The effect of change in the kidney allocation policy on outcomes of a sole transplant center in a single Donor Service Area (DSA).

P8.2: The effect of change in the kidney allocation policy on outcomes of a sole transplant center in a single Donor Service Area (DSA).

The history of ethical principles in liver transplant organ allocation in the united states: how historical and proposed allocations system fare in balancing utility vs. urgency and justice vs. pragmatism.

The United States (US) liver transplant community is processing changes to the allocation system and developing a new proposal that will result in even greater change. This review evaluates the ethical implications of these decisions, focusing on two sets of competing ethical principles (Urgency vs. Utility and Justice vs. Pragmatism). About four years ago, the Organ Procurement and Transplantation Network (OPTN) implemented the Acuity Circle Model to replace the geographic boundaries of organ procurement organizations (OPOs). Here, we review how effectively this model reduced regional variation in access and improved waitlist survival. Likewise, the OPTN is planning to transition to a continuous distribution model which will redefine the scoring systems for allocation. We will discuss how the ethical priorities discussed above should be considered while developing the new system. Every change in organ allocation policy must balance competing ethical imperatives. Although our community's emphasis on urgency over utility is appropriate, we should study the potential benefits of considering utility in the system. Meanwhile, our push for more Justice in the system should remain our imperative and Pragmatism should only be considered to minimize the costs of these changes.

Heart Retransplantation Under the 2018 Adult Heart Allocation Policy

BackgroundThe purpose of the present study was to characterize the impact of the 2018 adult heart allocation policy change on waiting list and posttransplant outcomes of heart retransplantation in the United States. MethodsAll adults listed for heart retransplantation from May 2015 to June 2022 were identified using the United Network for Organ Sharing database. Patients were stratified into eras (era 1 and era 2) based on the heart allocation change on October 18, 2018. Competing risks regressions and Cox proportional hazards models were used to assess differences across eras in waiting list outcomes and 1-year posttransplant survival, respectively. ResultsThe analysis included 356 repeat heart transplant recipients, with 207 (58%) receiving retransplantation during era 2. Patients who received a retransplant in era 2 were more commonly bridged with extracorporeal membrane oxygenation (21% vs 8%, P < .01) and intra-aortic balloon pump (29% vs 13%, P < .001) and had a lower likelihood of death/deterioration on the waiting list (subdistribution hazard ratio, 0.52; 95% CI, 0.33-0.82) compared with those in era 1. Rates of 30-day mortality (7% vs 7%, P = .99) and 1-year survival (82% vs 87%, P = .27) were not significantly different among retransplantation recipients across eras. After adjustment, retransplantation in era 2 was not associated with an increased hazard of mortality (adjusted hazard ratio, 1.13; 95% CI, 0.55-2.30). The gap in 1-year mortality between primary transplant and retransplant recipients increased from era 1 to 2. ConclusionsHeart retransplantation candidates have experienced improved waiting list outcomes after the 2018 adult heart allocation policy, without significant changes to posttransplant survival.

Survival After Simultaneous Heart-kidney Transplant in Recipients With a Durable LVAD and Chronic Kidney Disease: Effect of the 2018 Heart Allocation Policy Change.

Heart transplantation remains the most definitive therapy for qualified candidates with end-stage heart failure. Concomitant kidney disease is common in this population prompting an increase in simultaneous heart-kidney (SHK) transplantation in recent years. The goal of our study was to explore the effects of the 2018 heart allocation policy (HAP) change on candidate listing characteristics and compare survival rates at 1 y in patients that were supported with a left ventricular assist device (LVAD) pretransplant and underwent SHK or heart alone transplant (HAT). We used data from the Scientific Registry of Transplant Recipients and identified all adults who underwent primary SHK or HAT between January 2010 and March 2022. Recipients supported with a durable LVAD and estimated glomerular filtration rate <60 mL/min/1.73 m 2 were selected (n = 309 SHK; 217 pre- and 92 post-HAP and n = 3,324 HAT; 2738 pre- and 586 post-HAP). Difference in survival at 1 y did not reach statistical significance. Comparing the 1-y survival of SHK and HAT recipients who were bridged with LVAD pre-HAP, we found no significant difference ( P = 0.694). Adjusting for the same covariates in a multivariable model did not affect the results (SHK versus HAT hazard ratio 0.84 [0.51, 1.37]; P = 0.48). In contrast, SHK recipients supported with an LVAD who were listed and transplanted post-HAP change had significantly lower 1-y survival, when compared with HAT ( P = 0.037). Our findings suggest that the HAP change had a potentially negative impact on the survival of select patients undergoing SHK transplant. Further research is warranted in this area.

The Association of the UNOS Heart Allocation Policy Change With Transplant and Left Ventricular Assist Device Access and Outcomes

In October 2018, the allocation policy for adult orthotopic heart transplant (OHTx) in the United States was changed, with the goal of reducing waitlist mortality and providing broader sharing of donor organs within the United States. This study aimed to assess the association of this policy change with changes in access to OHTx versus left ventricular assist devices (LVADs), overall and in key sociodemographic subgroups, in the United States from 2016 to 2019. We identified all patients receiving OHTx or LVAD between 2016 and 2019 using the National Inpatient Sample. Controlling for medical co-morbidities, prepolicy trends, and within-hospital-year effects, we fit a dynamic logistic regression model to evaluate patient and hospital factors associated with receiving OHTx versus LVAD before versus after policy change. We also examined the frequency of temporary mechanical circulatory support in the same fashion. We identified 2,264 patients who received OHTx and 3,157 who received LVADs during the study period. In its first year of implementation, the United Network for Organ Sharing policy change of 2018 was associated with no overall change utilization of OHTx versus LVAD. In OHTx recipients, the frequency of use of temporary mechanical circulatory support changed from 15.6% in the before period to 42.6% in the after period (p<0.001). Although the policy change was associated with differences in the odds of receiving an OHTx versus LVAD between different regions of the country, there were no significant changes based on age, gender, race/ethnicity, insurance status, or rurality. In conclusion, the United Network for Organ Sharing policy change on access to OHTx was associated with no overall change in OHTx versus LVAD use in its first year of implementation although we observed small changes in relative odds of transplant based on rurality. Shifts in regional allocation were not significant overall, although certain regions appeared to have a relative increase in their use of OHTx.

Decreased survival of simultaneous heart-kidney transplant recipients in the new heart allocation era

In 2018, the United Network for Organ Sharing (UNOS) modified their heart allocation policy to reduce waitlist mortality. Rates of simultaneous heart-kidney transplant (SHKT) have dramatically increased in recent years, despite increased rates of post-transplant renal failure in the new policy era. This study sought to investigate the impact of the new allocation system on waitlist and post-transplant outcomes of simultaneous heart-kidney transplantation. Adult patients listed for SHKT between 2012 and 2021 were included. Patients were cross-validated across both Thoracic and Kidney UNOS databases to confirm accurate listing and transplant data. Patients were stratified according to listing era. The Fine and Gray model was used to assess waitlist outcomes and post-transplant renal graft function. Kaplan Meier analysis and Cox regression were used to compare post-transplant survival. A total of 2,588 patients were included, of whom 1,406 (54.1%) were listed between 2012 - 2018 (Era 1) and 1,182 (45.9%) between 2019 - 2021(Era 2). Era 2 was associated with increased likelihood of transplant (aSHR: 1.52; p<0.01) and decreased waitlist mortality (aSHR: 0.63; p<0.01). Post-transplant survival at 2 years was decreased in Era 2 (78.8% vs. 86.9%; p<0.01). Undersized hearts (HR: 2.02; p<0.01), use of extracorporeal membrane oxygenation (HR: 2.67; p<0.1), and transplants performed following the policy change (HR: 1.45; p=0.03) were associated with increased mortality. Actuarial survival (combined waitlist and post-transplant) was significantly lower in the modern era (71.6% vs. 62.2%; p=0.02). The allocation policy change has improved waitlist outcomes in patients listed for SHKT, but potentially at the cost of worsened post-transplant outcomes.

Improving outcomes of in situ split liver transplantation in Italy over the last 25 years

Split liver transplant(ation) (SLT) is still considered a challenging procedure that is by no means widely accepted. We aimed to present data on 25-year trends in SLT in Italy, and to investigate if, and to what extent, outcomes have improved nationwide during this time. The study included all consecutive SLTs performed from May 1993 to December 2019, divided into three consecutive periods: 1993-2005, 2006-2014, and 2015-2019, which match changes in national allocation policies. Primary outcomes were patient and graft survival, and the relative impact of each study period. SLT accounted for 8.9% of all liver transplants performed in Italy. A total of 1,715 in situ split liver grafts were included inthe analysis: 868 left lateral segments (LLSs) and 847 extended right grafts (ERGs). A significant improvement in patient and graft survival (p <0.001) was observed with ERGs over the three periods. Predictors of graft survival were cold ischaemia time (CIT) <6h (p= 0.009), UNOS status 2b (p <0.001), UNOS status 3 (p= 0.009), and transplant centre volumes: 25-50 cases vs. <25 cases (p= 0.003). Patient survival was significantly higher with LLS grafts in period 2 vs. period 1 (p= 0.008). No significant improvement in graft survival was seen over the three periods, where predictors of graft survival were CIT <6h (p= 0.007), CIT <6h vs. ≥10h (p= 0.019), UNOS status 2b (p= 0.038), and UNOS status 3 (p= 0.009). Retransplantation was a risk factor in split liver graft recipients, with significantly worse graft and patient survival for both types of graft (p <0.001). Our analysis showed Italian SLT outcomes to have improved over the last 25 years. These results could help to dispel reservations regarding the use of this procedure. Split liver transplant(ation) (SLT) is still considered a challenging procedure and is by no means widely accepted. This study included all consecutive in situ SLTs performed in Italy from May 1993 to December 2019. With more than 1,700 cases, it is one of the largest series, examining long-term national trends in in situ SLT since its introduction. The data presented indicate that the outcomes of SLT improved during this 25-year period. Improvements are probably due to better recipient selection, refinements in surgical technique, conservative graft-to-recipient matching, and the continuous, yet carefully managed, expansion of donor selection criteria under a strict mandatory split liver allocation policy. These results could help to dispel reservations regarding the use of this procedure.

Improved waitlist and comparable post-transplant outcomes in simultaneous heart-kidney transplantation under the 2018 heart allocation system

ObjectiveThis study aimed to investigate the clinical trends and the impact of the 2018 heart allocation policy change on both waitlist and post-transplant outcomes in simultaneous heart-kidney transplantation in the United States. MethodsThe United Network for Organ Sharing registry was queried to compare adult patients before and after the allocation policy change. This study included 2 separate analyses evaluating the waitlist and post-transplant outcomes. Multivariable analyses were performed to determine the 2018 allocation system's risk-adjusted hazards for 1-year waitlist and post-transplant mortality. ResultsThe initial analysis investigating the waitlist outcomes included 1779 patients listed for simultaneous heart-kidney transplantation. Of these, 1075 patients (60.4%) were listed after the 2018 allocation policy change. After the policy change, the waitlist outcomes significantly improved with a shorter waitlist time, lower likelihood of de-listing, and higher likelihood of transplantation. In the subsequent analysis investigating the post-transplant outcomes, 1130 simultaneous heart-kidney transplant recipients were included, where 738 patients (65.3%) underwent simultaneous heart-kidney transplantation after the policy change. The 90-day, 6-month, and 1-year post-transplant survival and complication rates were comparable before and after the policy change. Multivariable analyses demonstrated that the 2018 allocation system positively impacted risk-adjusted 1-year waitlist mortality (sub-hazard ratio, 0.66, 95% CI, 0.51-0.85, P < .001), but it did not significantly impact risk-adjusted 1-year post-transplant mortality (hazard ratio, 1.03; 95% CI, 0.72-1.47, P = .876). ConclusionsThis study demonstrates increased rates of simultaneous heart-kidney transplantation with a shorter waitlist time after the 2018 allocation policy change. Furthermore, there were improved waitlist outcomes and comparable early post-transplant survival after simultaneous heart-kidney transplantation under the 2018 allocation system.

Biventricular Assist Devices as a Bridge to Heart Transplantation Under the New Donor Heart Allocation System in the United States.

Biventricular assist devices (BiVADs) for pre-heart transplant care is rare. The outcomes of pretransplant BiVAD support after the 2018 heart transplant allocation policy change are entirely unknown at this time. The United Network of Organ Sharing database was retrospectively queried from October 2018 to June 2022 to identify patients supported to transplant with BiVADs. They were compared to patients listed as Status 2 for heart transplantation with an isolated VAD (uni-VAD). The primary outcome of interest was 1 year survival. Secondary outcomes included length of stay, posttransplant stroke, dialysis, and pacemaker implantation. The frequency of BiVAD use for heart transplantation has remained unchanged after the 2018 allocation policy change, making up approximately 2% of transplant recipients annually. Patients supported with BiVADs appeared to be similar to patients supported with uni-VADs. One year survival was similar between the groups (88.57% vs. 87.90%). Length of stay was longer and there was a trend toward higher frequencies of posttransplant dialysis use. Patients supported to transplant with BiVADs appear to have posttransplant outcomes comparable to patients commonly listed as Status 2 with an isolated VAD. Compared to past analyses, there is a suggestion of improved survival with the 2018 allocation policy change.

Impella 5.5 as a bridge to heart transplantation: Waitlist outcomes in the United States.

The 2018 United Network for Organ Sharing allocation policy change has led to a significant increase in the use of mechanical circulatory support devices in patients listed for orthotopic heart transplantation. However, there has been a paucity of data regarding the newest generation Impella 5.5, which received FDA approval in 2019. The United Network for Organ Sharing registry was queried for all adults awaiting orthotopic heart transplantation who received Impella 5.5 support during their listing period. Waitlist, device, and early post-transplant outcomes were assessed. A total of 464 patients received Impella 5.5 support during their listing period with a median waitlist time of 19 days. Among them, 402 (87%) patients were ultimately transplanted, with 378 (81%) being directly bridged to transplant with the device. Waitlist death (7%) and clinical deterioration (5%) were the most common reasons for waitlist removal. Device complications and failure were uncommon (<5%). The most common post-transplant complication was acute kidney injury requiring dialysis (16%). Survival at 1-year post-transplant survival was 89.5%. Since its approval, the Impella 5.5 has been increasingly used as a bridge to transplant. This analysis demonstrates robust waitlist and post-transplant outcomes with minimal device-related and postoperative complications.

Temporary Mechanical Circulatory Support Use and Clinical Outcomes of Simultaneous Heart/Kidney Transplant Recipients in the Pre- and Post-heart Allocation Policy Change Eras.

The use of temporary mechanical circulatory support (tMCS) devices (intra-aortic balloon pump; Impella 2.5, CP, 5.0; venoarterial extracorporeal membrane oxygenation) increased significantly across the United States for heart transplant candidates after the allocation policy change. Whether this practice change also affected simultaneous heart-kidney (SHK) candidates and recipient survival is understudied. We used the Scientific Registry of Transplant Recipients database to identify adult SHK recipients between January 2010 and March 2022. The population was stratified into pre- and post-heart allocation change cohorts. Kaplan-Meier curves were generated to compare 1-y survival rates. A Cox proportional hazards model was used to investigate the effect of allocation period on patient survival. Recipient outcomes bridged with eligible tMCS devices were compared in the post-heart allocation era. In a separate analysis, SHK waitlist mortality was evaluated between the allocation eras. A total of 1548 SHK recipients were identified, and 1102 were included in the final cohort (534 pre-allocation and 568 post-allocation change). tMCS utilization increased from 17.9% to 51.6% after the allocation change, with venoarterial extracorporeal membrane oxygenation use rising most significantly. However, 1-y post-SHK survival remained unchanged in the full cohort (log-rank P = 0.154) and those supported with any of the eligible tMCS devices. In a separate analysis (using a larger cohort of all SHK listings), SHK waitlist mortality at 1 y was significantly lower in the current allocation era ( P = 0.002). Despite the remarkable increase in tMCS use in SHK candidates after the heart allocation change, 1 y posttransplant survival remained unchanged. Further studies with larger cohorts and longer follow-ups are needed to confirm these findings.

Increasing waiting times for status 2 patients in new United Network for Organ Sharing allocation system: Impact on waitlist and posttransplant outcomes

ObjectiveSince the heart transplant allocation policy change in 2018, there has been an increase in temporary mechanical circulatory support for Status 2 patients. We sought to examine the temporal pattern of waitlist and posttransplant outcomes for Status 2 patients. MethodsAdult patients in the United Network for Organ Sharing registry who were listed as Status 2 from January 2019 to June 2022 were included. Temporal trends in waitlist time, waitlist events, and posttransplant outcomes were assessed. Probability of transplant or death after being listed was compared over time. Multivariable regression was performed to identify risk factors for mortality after transplant. ResultsA total of 6310 patients were included. From 2019 to 2022, the number of Status 2 patients listed increased from 4.2 to 5.9 per day. Microaxial ventricular assist devices at Status 2 listing increased over time (P < .001). During the study period, median waitlist time (18 days vs 23 days, P < .001) as well as Status 2 days (8 days vs 12 days, P < .001) increased. Waitlist mortality remained stable (5.5%); however, probability of transplant within 90 days of Status 2 listing progressively declined (P < .001). Finally, longer waitlist duration was independently associated with 30-day posttransplant mortality (odds ratio, 1.01; 95% confidence interval, 1.00-1.01, P = .02). ConclusionsSince the allocation policy change there has been a steady rise in the number of patients listed for Status 2. This has led to increasing waitlist times and lower probability of transplantation for Status 2 patients, which may have negative consequences for posttransplant outcomes.

TOP1: Outcomes in Heart Transplant Recipients by Bridge-To-Transplant Strategy When Using the SherpaPak Cardiac Transport System

Background: The last several years have seen a rise in the use of mechanical circulatory support (MCS) to bridge heart transplant recipients. This may be due to expanding indications for devices such as extracorporeal membrane oxygenation (ECMO), but also to changes in the UNOS allocation policy in 2018. A controlled hypothermic organ preservation system, the SherpaPak Cardiac Transport System (CTS), was also introduced in 2018 and has grown in utilization with reports of improved post-transplant outcomes. We present here a subgroup analysis in recipients bridged with various MCS devices in the GUARDIAN-Heart Registry. Methods: The GUARDIAN-Heart registry is an international, multicenter registry assessing outcomes after transplant using CTS preservation. A retrospective review of clinical outcomes in transplant recipients with ventricular assist devices (VAD), intra-aortic balloon pumps (IABP) and ECMO prior to transplant were examined using summary statistics. Further analysis with ongoing enrollment will be available for presentation. Results: A total of 373 heart transplant recipients with donor hearts transported using the CTS system were included in this analysis. VADs were used in 171 recipients, IABP in 165, and ECMO in 37 recipients. Average ischemic times were over 3.5 hours for all cohorts. Mean IMPACT scores increased across groups (VAD = 6.8, IABP = 9.4, ECMO = 15.9), as did the rates of severe PGD post-transplant (VAD = 4.7%, IABP 7.9%, ECMO 18.9%). However, overall one-year survival was excellent (LVAD = 90.3%, IABP = 94.1%, ECMO = 93.3%). Median ICU length of stay was longer in the EMCO cohort (13.0 days) compared to the LVAD and IABP cohorts (each 7.0 days), as well as total hospital length of stay at 27.0 (ECMO) compared to 21.5 (LVAD) and 18.0 days (IABP). Conclusions: Despite average ischemic times in excess of 3.5 hours, use of the SherpaPak CTS for recipients with various bridging strategies results in excellent survival.

Increased volume of organ offers and decreased efficiency of kidney placement under circle-based kidney allocation

The newest kidney allocation policy kidney allocation system 250 (KAS250) broadened geographic distribution while increasing allocation system complexity. We studied the volume of kidney offers received by transplant centers and the efficiency of kidney placement since KAS250. We identified deceased-donor kidney offers (N = 907,848; N = 36,226 donors) to 185 US transplant centers from January 1, 2019, to December 31, 2021 (policy implemented March 15, 2021). Each unique donor offered to a center was considered a single offer. We compared the monthly volume of offers received by centers and the number of centers offered before the first acceptance using an interrupted time series approach (pre-/post-KAS250). Post-KAS250, transplant centers received more kidney offers (level change: 32.5 offers/center/mo, P < .001; slope change: 3.9 offers/center/mo, P = .003). The median monthly offer volume post-/pre-KAS250 was 195 (interquartile range 137-253) vs. 115 (76-151). There was no significant increase in deceased-donor transplant volume at the center level after KAS250, and center-specific changes in offer volume did not correlate with changes in transplant volume (r = −0.001). Post-KAS250, the number of centers to whom a kidney was offered before acceptance increased significantly (level change: 1.7 centers/donor, P < .001; slope change: 0.1 centers/donor/mo, P = .014). These findings demonstrate the logistical burden of broader organ sharing, and future allocation policy changes will need to balance equity in transplant access with the operational efficiency of the allocation system.

Coase and Cap-and-Trade: Evidence on the Independence Property from the European Carbon Market

I examine the Coasean independence property in a large multinational cap-and-trade scheme for greenhouse gas emissions, the EU Emissions Trading System. I analyze whether emissions of power producers are independent from allowance allocations by leveraging a change in allocation policy for a difference-in-difference strategy. The evidence suggests that the independence property holds overall and for larger emitters and that firms respond to the loss in allocation by increasing allowance purchases. Suggestive evidence for small emitters indicates that trading costs or behavioral bias distorts their emission decisions. However, their small emission share leaves the independence property intact at the sector level. (JEL L94, L98, Q48, Q51, Q54, Q58)

(65) Assessment of Heart Transplantation Allocation Policy Change by Zip Code and Median Household Income: An OPTN Database Analysis

(65) Assessment of Heart Transplantation Allocation Policy Change by Zip Code and Median Household Income: An OPTN Database Analysis