Ten-year experience with extended criteria cardiac transplantation

Donation after circulatory death improves probability of heart transplantation in waitlisted candidates and results in post-transplant outcomes similar to those achieved with brain-dead donors

OBJECTIVE

To quantitate the impact of heart donation after circulatory death (DCD) donor utilization on both waitlist and post-transplant outcomes in the United States.

METHODS

The United Network for Organ Sharing database was queried to identify all adult waitlisted and transplanted candidates between October 18, 2018, and December 31, 2022. Waitlisted candidates were stratified according to whether they had been approved for donation after brain death (DBD) offers only or also approved for DCD offers. The cumulative incidence of transplantation was compared between the 2 cohorts. In a post-transplant analysis, 1-year post-transplant survival was compared between unmatched and propensity-score-matched cohorts of DBD and DCD recipients.

RESULTS

A total of 14,803 candidates were waitlisted, including 12,287 approved for DBD donors only and 2516 approved for DCD donors. Overall, DCD approval was associated with an increased sub-hazard ratio (HR) for transplantation and a lower sub-HR for delisting owing to death/deterioration after risk adjustment. In a subgroup analysis, candidates with blood type B and status 4 designation received the greatest benefit from DCD approval. A total of 12,238 recipients underwent transplantation, 11,636 with DBD hearts and 602 with DCD hearts. Median waitlist times were significantly shorter for status 3 and status 4 recipients receiving DCD hearts. One-year post-transplant survival was comparable between unmatched and propensity score-matched cohorts of DBD and DCD recipients.

CONCLUSIONS

The use of DCD hearts confers a higher probability of transplantation and a lower incidence of death/deterioration while on the waitlist, particularly among certain subpopulations such as status 4 candidates. Importantly, the use of DCD donors results in similar post-transplant survival as DBD donors.

Non-inferior outcomes in lower urgency patients transplanted with extended criteria donor hearts

BACKGROUND

Recent work has suggested that outcomes among heart transplant patients listed at the lower-urgency (United Network for Organ Sharing Status 4 or 6) status may not be significantly impacted by donor comorbidities. The purpose of this study was to investigate outcomes of extended criteria donors (ECD) in lower versus higher urgency patients undergoing heart transplantation.

METHODS

The United Network for Organ Sharing (UNOS) database was queried for all adult patients undergoing heart transplantation from October 18, 2018 through December 31, 2021. Patients were stratified by degree of urgency (higher urgency: UNOS 1 or 2 vs lower urgency: UNOS 4 or 6) and receipt of ECD hearts, as defined by donor hearts failing to meet established acceptable use criteria. Outcomes were compared using propensity score matched cohorts.

RESULTS

Among 9,160 patients included, 2,320 (25.4%) were low urgency. ECD hearts were used in 35.5% of higher urgency (HU) patients and 39.2% of lower urgency (LU) patients. While ECD hearts had an impact on survival among high-urgency patients (p < 0.01), there was no difference in 1- and 2-year survival (p > 0.05) found among low urgency patients receiving ECD versus standard hearts. Neither ECDs nor individual ECD criteria were independently associated with mortality in low urgency patients (p > 0.05).

CONCLUSIONS

Post-transplant outcomes among low urgency patients are not adversely affected by receipt of ECD vs. standard hearts. Expanding the available donor pool by optimizing use of ECDs in this population may increase transplant frequency, decrease waitlist morbidity, and improve postoperative outcomes for the transplant community at large.

Heart transplantation from donation after circulatory death: Impact on waitlist time and transplant rate

The effect of using donation after circulatory death (DCD) hearts on waitlist outcomes has not been substantiated. We retrospectively analyzed 184 heart transplant (HT) candidates at our institution from 2019 to 2021. Patients were stratified into 2 observation periods centered on September 12, 2020, when the adult DCD HT program officially began. The primary outcome was a comparison of transplant rate between period 1 (pre-DCD) and period 2 (post-DCD). Secondary outcomes included waitlist time-to-transplant, waitlist mortality rate, independent predictors of incidence of HT, and posttransplant outcomes. A total of 165 HTs (n = 92 in period 1 and n = 73 in period 2) were performed. The median waitlist time-to-transplant decreased from 47.5 to 19 days in periods 1 and 2, respectively (P = .004). The transplant rate increased from 181 per 100 patient-years in period 1 to 579 per 100 patient-years in period 2 (incidence rate ratio, 1.87; 95% CI, 1.04-3.38; P = .038). There were no statistical differences in waitlist mortality rate (P = .566) and 1-year survival (P = .699) between the 2 periods. DCD HTs (n = 36) contributed to 49.3% of overall HT activity in period 2. We concluded that utilization of DCD hearts significantly reduced waitlist time and increased transplant rate. Short-term posttransplant outcomes were comparable between the pre-DCD and post-DCD periods.

Use of extended criteria donor hearts in combined heart-kidney transplant confers greater risk of mortality

BACKGROUND

Extended criteria donors (ECD) hearts have demonstrated acceptable outcomes in select populations. However, their use in patients undergoing simultaneous heart-kidney transplantation (SHKT) has not been explored. This study is assessed the effect of ECD hearts in patients undergoing SHKT vs isolated heart transplants (IHT).

METHODS

The United Network for Organ Sharing (UNOS) database was queried for all adult patients undergoing IHT and SHKT. Patients were stratified by receipt of ECD heart, defined as donor hearts failing to meet established acceptable use criteria. Interaction effects between ECDs and simultaneous kidney transplants were generated. Postoperative outcomes, risk factors, and patient/graft survival were compared across cohorts using Fine-Gray, Kaplan Meier, and Cox Proportional Hazards analyses.

RESULTS

Among 26,207 patients included, 1,766 (7%) underwent SHKT. ECD hearts were used in 25% of both IHT and SHKT cohorts. Five-year survival among SHKT/ECD patients (67.3%) was reduced (p < 0.01) compared to SHKT/SDC (80.3%), IHT/ECD (78.1%) and IHT/SCD (80.0%) groups. Among SHKT patients, use of ECD hearts was associated with increased risk (SHR: 1.48; p < 0.01) of renal graft failure compared to SCD hearts. Among SHKT patients, receipt of an ECD heart, and individual ECD criteria (coronary disease and size mismatch >20%), predicted mortality. The interaction effect of receiving both ECD and SHKT predicted mortality and graft failure (HR 1.43; p < 0.01).

CONCLUSIONS

Patients undergoing SHKT with an ECD heart face greater risks of mortality and graft failure in comparison to those undergoing IHT with ECD hearts. Careful selection of donor organs should be applied to this high-risk cohort.

Extended criteria donor organ use for heart-lung transplantation in the modern era

BACKGROUND

Demand for donor hearts and lungs exceeds their supply. Extended Criteria Donor (ECD) organs are used to help meet this demand, but their impact on heart-lung transplantation outcomes is poorly characterized.

METHODS AND RESULTS

The United Network for Organ Sharing was queried for data on adult heart-lung transplantation recipients (n = 447) from 2005‒2021. Recipients were stratified based on whether they received ECD hearts and/or lungs. Morbidity was analyzed using Kruskal-Wallis, chi-square, and Fisher's exact tests. Mortality was analyzed using Kaplan-Meier estimation, log-rank tests and Cox regression. Sixty-five (14.5%) patients received two ECD organs, 134 (30.0%) received only an ECD lung, and 65 (14.5%) only an ECD heart. Recipients of two ECD organs were older, more likely to have diabetes, and more likely transplanted from 2015‒2021 (p < 0.05). Groups did not differ by pre-transplant diagnosis, intensive care unit disposition, life support use, or hemodynamics. Group five-year survival rates ranged from 54.5% to 63.2% (p = 0.428). Groups did not differ by 30-day mortality, strokes, graft rejection, or hospital length of stay.

CONCLUSIONS

Using ECD hearts and/or lungs for heart-lung transplantation is not associated with increased mortality and is a safe strategy for increasing donor organ supply in this complex patient population.

Complement-targeting therapeutics for ischemia-reperfusion injury in transplantation and the potential for ex vivo delivery

Organ shortages and an expanding waitlist have led to increased utilization of marginal organs. All donor organs are subject to varying degrees of IRI during the transplant process. Extended criteria organs, including those from older donors and organs donated after circulatory death are especially vulnerable to ischemia-reperfusion injury (IRI). Involvement of the complement cascade in mediating IRI has been studied extensively. Complement plays a vital role in the propagation of IRI and subsequent recruitment of the adaptive immune elements. Complement inhibition at various points of the pathway has been shown to mitigate IRI and minimize future immune-mediated injury in preclinical models. The recent introduction of ex vivo machine perfusion platforms provides an ideal window for therapeutic interventions. Here we review the role of complement in IRI by organ system and highlight potential therapeutic targets for intervention during ex vivo machine preservation of donor organs.

Quantitative stiffness assessment of cardiac grafts using ultrasound in a porcine model: A tissue biomarker for heart transplantation

Background

Heart transplantation is the definitive treatment for many cardiovascular diseases. However, no ideal approach is established to evaluate heart grafts and it mostly relies on qualitative interpretation of surgeon based on the organ aspect including anatomy, color and manual palpation. In this study we propose to assess quantitatively the Shear Wave Velocity (SWV) using ultrasound as a biomarker of cardiac viability on a porcine model.

Methods

The SWV was assessed quantitatively using a clinical ultrasound elastography device (Aixplorer, Supersonics Imagine, France) linked to a robotic motorized arm (UR3, Universal Robots, Denmark) and the elastic anisotropy was obtained using a custom ultrasound research system.

SWV was evaluated as function of time in two porcine heart model during 20h at controlled temperature (4°C). One control group (N = 8) with the heart removed and arrested by cold cardioplegia and immerged in a preservation solution. One ischemic group (N = 6) with the organ harvested after 30 min of in situ warm ischemia, to mimic a donation after cardiac death. Hearts graft were revived at two preservation times, at 4 h (N = 11) and 20 h (N = 10) and the parameters of the cardiac function evaluated.

Findings

On control hearts, SWV remained unchanged during the 4h of preservation. SWV increased significantly between 4 and 20h. For the ischemic group, SWV was found higher after 4h (3.04 +/- 0.69 vs 1.69+/-0.19 m/s, p = 0.007) and 20h (4.77+/-1.22 m/s vs 3.40+/-0.75 m/s, p = 0.034) of preservation with significant differences. A good correlation between SWV and cardiac function index was found (r²=0.88) and manual palpation score (r²=0.81).

Interpretation

Myocardial stiffness increase was quantified as a function of preservation time and harvesting conditions. The correlation between SWV and cardiac function index suggests that SWV could be used as a marker of graft viability. This technique may be transposed to clinical transplantation for assessing the graft viability during transplantation process.

Funding

FRM PME20170637799, Agence Biomédecine AOR Greffe 2017, ANR-18-CE18-0015.

Recent advances in porcine cardiac xenotransplantation: from aortic valve replacement to heart transplantation

INTRODUCTION

Cardiac xenotransplantation presents significant potential to the field of heart failure by addressing the high demand for donor organs. The availability of xenograft hearts would substantially augment the number of life-saving organs available to patients and may ultimately liberalize eligibility criteria for transplantation.

AREAS COVERED

In this review, we will discuss the need for cardiac xenotransplantation and the history of research and clinical practice in this field. Specifically, we address immunologic concepts and clinical lessons learned from heart valve replacement using xenogeneic tissues, the advancement of xenotransplantation using organs from genetically modified animals, and the progression of this research to the first-in-man pig-to-human heart transplantation.

EXPERT OPINION

Cardiac xenotransplantation holds tremendous promise, but the indications for this new treatment will need to be clearly defined because mechanical support with ventricular assist devices and total artificial hearts are increasingly successful alternatives for adults in heart failure. Cardiac xenotransplantation will also serve as temporary bridge to allotransplantation in babies with complex congenital heart disease who are too small for the currently available mechanical assist devices. Moreover, xenotransplantation of the part of the heart containing a heart valve could deliver growing heart valve implants for babies with severe heart valve dysfunction.

Geographic Variation in Heart Transplant Extended Criteria Donors in the United States

BACKGROUND

Recent research has explored the use of higher risk extended criteria donors (ECDs) as a means of expanding the donor pool for heart transplantation. Here we sought to explore the current geographic distribution and survival outcomes of ECD utilization in various regions across the United States.

METHODS

The United Network for Organ Sharing database was retrospectively queried for adult primary heart transplantation from 2000 to 2019. The EXPAND trial definition of ECD was used: ischemic time ≥ 4 hours, ejection fraction < 50%, age > 55 years, and history of coronary artery disease. Geographic data and 2019 population estimates were obtained from the US Census Bureau.

RESULTS

Of the 42 642 transplants included in our analysis, 11 750 (27.6%) used ECDs. Region utilization of ECDs ranged from 18.4% to 46.5% of transplants. Region 6 had the highest utilization rate at 46.5%; this was primarily driven by the number of transplants with ischemic time ≥ 4 hours. Region 6 encompasses the largest total area (1.08 million square miles) and smallest population density (15.6 people per square mile). Region 8 had the lowest marginal donor utilization rate at 18.4%. Regions with high utilization of low ejection fractions, older donors, and donors with coronary artery disease (ie, regions 1 and 2) were able to maintain an average utilization rate of ECDs by maintaining short ischemic times.

CONCLUSIONS

Large discrepancies in the use of ECDs exist across the different United Network for Organ Sharing regions. This is primarily driven by longer ischemic times, likely guided by variance in population densities between different regions.

Trends and Outcomes of Cardiac Transplantation in the Lowest Urgency Candidates

Background Due to discrepancies between donor supply and recipient demand, the cardiac transplantation process aims to prioritize the most medically urgent patients. It remains unknown how recipients with the lowest medical urgency compare to others in the allocation process. We aimed to examine differences in clinical characteristics, organ allocation patterns, and outcomes between cardiac transplantation candidates with the lowest and highest medical urgency. Methods and Results We performed a retrospective analysis of the United Network for Organ Sharing database. Patients listed for cardiac transplantation between January 2011 and May 2020 were stratified according to status at time of transplantation. Baseline recipient and donor characteristics, waitlist survival, and post-transplantation outcomes were compared in the years before and after the 2018 allocation system change. Lower urgency patients in the old system were older (58.5 vs. 56 years) and more likely female (54.4% vs. 23.8%) compared to the highest urgency patients, and these trends persisted in the new system (p<0.001, all). Donors for the lowest urgency patients were more likely older, female, or have a history of CMV, hepatitis C, or diabetes (p<0.01, all). The lowest urgency patients had longer waitlist times, and under the new allocation system received organs from shorter distances with decreased ischemic times (178 vs. 269 miles, 3.1 vs 3.5 hours, p<0,001, all). There was no difference in post-transplantation survival (p<0.01, all). Conclusions Patients transplanted as lower urgency receive hearts from donors with additional comorbidities compared to higher urgency patients, but outcomes are similar at one year.

The Impact of Adverse Events on Functional Capacity and Quality of Life After HeartWare Ventricular Assist Device Implantation

Left ventricular assist devices (LVADs) improve quality of life (QoL) and functional capacity (FC) for patients with advanced heart failure. The association between adverse events (AEs) and changes in QoL and FC are unknown. Patients treated with the HeartWare ventricular assist device (HVAD) with paired 6-minute walk distance (6MWD, n = 263) and Kansas City Cardiomyopathy Questionnaires (KCCQ, n = 272) at baseline and 24 months in the ENDURANCE and ENDURANCE Supplemental Trial databases were included. Patients were stratified based upon occurrence of clinically significant AEs during the first 24 months of support and analyzed for the mean change in 6MWD and KCCQ. The impact of AE frequency on change in 6MWD and KCCQ from baseline to 24 months was evaluated. Of the AEs examined, only sepsis was associated with an improvement in 6MWD (109 m vs. 16 m, p = 0.002). Patients without improvement in 6MWD test from baseline to 24 months had significantly more AEs than those with FC improvement (p = 0.0002). Adverse events did not affect the KCCQ overall summary score. In this analysis, patients with fewer AEs had greater improvement in FC during the 24-month follow up. The frequency of AEs did not have a significant impact on QoL after LVAD implantation.

Impact of implantation time on early function of cardiac transplant

BACKGROUND

Data on out-of-ice implantation ischemia in heart transplant are scarce. We examined implantation time's impact on allograft dysfunction.

METHODS

We conducted a single-site retrospective review of all primary adult heart transplants from June 2012 to August 2019 for implantation warm ischemic time (WIT), defined as first atrial stitch to aortic crossclamp removal. Univariate regression was used to assess the relationship of perioperative variables to primary graft dysfunction (PGD) and to pulmonary artery pulsatility index (PAPi) at postoperative hour 24. A threshold of p < .10 was set for the inclusion of covariates in multivariate regression. Secondary analyses evaluated for consistency among alternative criteria for allograft dysfunction. A post hoc subgroup analysis examined WIT effect in prolonged total ischemia of 240 min or longer.

RESULTS

Complete data were available for 201 patients. Baseline characteristics were similar between patients who did and did not have WIT documented. In univariate analysis, female gender, longer total ischemic time (TIT), longer bypass time, greater blood transfusions, and pretransplant intensive care unit (ICU) care were associated with PGD, whereas longer bypass time was associated with worse PAPi and pretransplant ICU care was associated with better PAPi. In multivariate analysis, longer bypass time predicted PGD, and worse PAPi and preoperative ICU admission predicted PGD and better PAPi. Results did not differ in secondary or subgroup analyses.

CONCLUSIONS

This study is one of few examining the functional impact of cardiac implantation ischemia. Results suggest allograft implantation time alone may not impact postoperative graft function, which was driven by intraoperative bypass duration and by preoperative ICU care, instead.

Impact of donor-recipient age on cardiac transplant survival. Subanalysis of the Spanish Heart Transplant Registry

INTRODUCTION AND OBJECTIVES

The age of heart transplant recipients and donors is progressively increasing. It is likely that not all donor-recipient age combinations have the same impact on mortality. The objective of this work was to compare survival in transplant recipients according to donor-recipient age combinations.

METHODS

We performed a retrospective analysis of transplants performed between 1 January 1993 and 31 December 2017 in the Spanish Heart Transplant Registry. Pediatric transplants, retransplants and combined transplants were excluded (6505 transplants included). Four groups were considered: a) donor <50 years for recipient <65 years; b) donor <50 years for recipient ≥ 65 years; c) donor ≥ 50 years for recipient ≥ 65 years, and d) donor ≥ 50 years for recipient <65 years.

RESULTS

The most frequent group was young donor for young recipient (73%). There were differences in the median survival between the groups (P <.001): a) younger-younger: 12.1 years, 95%CI, 11.5-12.6; b) younger-older: 9.1 years, 95%CI, 8.0-10.5; c) older-older: 7.5 years, 95%CI, 2.8-11.0; d) older-younger: 10.5 years, 95%CI, 9.6-12.1. On multivariate analysis, independent predictors of mortality were the age of the donor and the recipient (0.008 and 0.001, respectively). The worst combinations were older-older vs younger-younger (HR, 1.57; 95%CI, 1.22-2.01; P <.001) and younger-older vs younger-younger (HR, 1.33; 95%CI, 1.12-1.58; P=.001).

CONCLUSIONS

Age (of the donor and recipient) is a relevant prognostic factor in heart transplant. The donor-recipient age combination has prognostic implications that should be identified when accepting an organ for transplant.

New Strategies to Expand and Optimize Heart Donor Pool: Ex Vivo Heart Perfusion and Donation After Circulatory Death: A Review of Current Research and Future Trends

Heart transplantation remains the definitive management for end-stage heart failure refractory to medical therapy. While heart transplantation cases are increasing annually worldwide, there remains a deficiency in organ availability with significant patient mortality while on the waiting list. Attempts have therefore been made to expand the donor pool and improve access to available organs by recruiting donors who may not satisfy the standard criteria for organ donation because of donor pathology, anticipated organ ischemic time, or donation after circulatory death. "Ex vivo" heart perfusion (EVHP) is an emerging technique for the procurement of heart allografts. This technique provides mechanically supported warm circulation to a beating heart once removed from the donor and before implantation into the recipient. EVHP can be sustained for several hours, facilitate extended travel time, and enable administration of pharmacological agents to optimize cardiac recovery and function, as well as allow assessment of allograft function before implantation. In this article, we review recent advances in expanding the donor pool for cardiac transplantation. Current limitations of conventional donor criteria are outlined, including the determinants of organ suitability and assessment, involving transplantation of donation after circulatory death hearts, extended criteria donors, and EVHP-associated assessment, optimization, and transportation. Finally, ongoing research relating to organ optimization and functional ex vivo allograft assessment are reviewed.

Relationship Between Change in Heart Transplant Volume and Outcomes: A National Analysis

INTRODUCTION

Although volume-outcome relationships in transplantation have been well-defined, the effects of large changes in center volume are less well understood. The purpose of the current study was to examine the impact of changes in center volume on outcomes after heart transplantation.

METHODS

Retrospective analysis was performed of adult patients undergoing heart transplant between 2000 and 2017 identified in the United Network for Organ Sharing database. Exclusions included annual volume <10. Patients were grouped according to percentage change in center volume from the previous year. Multivariable Cox regression models were adjusted for the significant preoperative variance identified on univariate analyses.

RESULTS

Of the 29,851 transplants during the study period, 64% were at centers with stable volume (±25% annual change), whereas 10% were performed at contracting (-25% change or more) and 26% were performed at growing (+25% change or more) centers. Average volume was lower with contracting centers compared with stable or growing programs (21 vs 36, P< .001). Thirty-day mortality was greater in decreasing centers (6% vs 4%, P < .001), with more acute rejection treatments at 1y (27% vs 24% P < .001). The adjusted risk of mortality among contracting centers was 1.25 ([1.07-1.46], P= .004), whereas growing centers had unaffected risk (0.90 [0.79-1.02], P= .103). Causes of death were similar between groups.

CONCLUSIONS

Rapid growth of transplant center volume has occurred at select centers in the United States without decrement in programmatic outcomes. Decreasing center volume has been associated with poorer outcomes, although the causative nature of this relationship requires further investigation.

The donor heart and organ perfusion technology

Recent advancement in organ perfusion technology has led to increase clinical transplantation of marginal donor organs and allow for distant procurement of cardiac allograft beyond the time limitation of cold static storage. Ex-situ heart perfusion also provides essential nutrients to maintain cell integrity, thereby reducing the risk of ischaemic injury for functional preservation and provides a platform to assess organ viability and feasibility, with the potential for pharmacotherapy to recover these hearts. Notably, the use of NMP has led to the first distant procurement cardiac transplantation from a donation after circulatory death (DCD) in 2014, which resulted in the adoption of DCD heart transplantation in 4 centres between the United Kingdom and Australia. To date, over 100 DCD heart transplants have been performed utilising cardiac perfusion system with an estimated 10-15% increase in transplant activity in the individual units. This review aims to provide an overview of current experience and outcomes using cardiac perfusion technology, including future technologies and recent advancement within the field.

Between-center disparities in access to heart transplantation in France: contribution of candidate and center factors - A comprehensive cohort study

Transplantation represents the last option for patients with advanced heart failure. We assessed between-center disparities in access to heart transplantation in France 1 year after registration and evaluated the contribution of factors to these disparities. Adults (n = 2347) registered on the French national waiting list between January 1, 2010, and December 31, 2014, in the 23 transplant centers were included. Associations between candidate and transplant center characteristics and access to transplantation were assessed by proportional hazards frailty models. Candidate blood groups O and A, sensitization, and body mass index ≥30 kg/m² were independently associated with lower access to transplantation, while female gender, severity of heart failure, and high serum bilirubin levels were independently associated with greater access to transplantation. Center factors significantly associated with access to transplantation were heart donation rate in the donation service area, proportion of high-urgency candidates among listed patients, and donor heart offer decline rate. Between-center variability in access to transplantation increased by 5% after adjustment for candidate factors and decreased by 57% after adjustment for center factors. After adjustment for candidate and center factors, five centers were still outside of normal variability. These findings will be taken into account in the future French heart allocation system.

Heart failure with reduced ejection fraction

Heart failure is a global public health problem that affects more than 26 million people worldwide. The global burden of heart failure is growing and is expected to increase substantially with the ageing of the population. Heart failure with reduced ejection fraction accounts for approximately 50% of all cases of heart failure in the United States and is associated with substantial morbidity and reduced quality of life. Several diseases, such as myocardial infarction, certain infectious diseases and endocrine disorders, can initiate a primary pathophysiological process that can lead to reduced ventricular function and to heart failure. Initially, ventricular impairment is compensated for by the activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system, but chronic activation of these pathways leads to worsening cardiac function. The symptoms of heart failure can be associated with other conditions and include dyspnoea, fatigue, limitations in exercise tolerance and fluid accumulation, which can make diagnosis difficult. Management strategies include the use of pharmacological therapies and implantable devices to regulate cardiac function. Despite these available treatments, heart failure remains incurable, and patients have a poor prognosis and high mortality rate. Consequently, the development of new therapies is imperative and requires further research.

Assessment of cardiac allograft systolic function by global longitudinal strain: From donor to recipient

BACKGROUND

Cardiac allografts are routinely evaluated by left ventricular ejection fraction (LVEF) before and after transplantation. However, myocardial deformation analyses with LV global longitudinal strain (GLS) are more sensitive for detecting impaired LV myocardial systolic performance compared with LVEF.

METHODS

We analyzed echocardiograms in 34 heart donor-recipient pairs transplanted at Duke University from 2000 to 2013. Assessments of allograft LV systolic function by LVEF and/or LV GLS were performed on echocardiograms obtained pre-explanation in donors and serially in corresponding recipients.

RESULTS

Donors had a median LVEF of 55% (25th, 75th percentile, 54% to 60%). Median donor LV GLS was -14.6% (-13.7 to -17.3%); LV GLS was abnormal (ie, >-16%) in 68% of donors. Post-transplantation, LV GLS was further impaired at 6 weeks (median -11.8%; -11.0 to -13.4%) and 3 months (median -11.4%; -10.3 to -13.9%) before recovering to pretransplant levels in follow-up. Median LVEF remained ≥50% throughout follow-up. We found no association between donor LV GLS and post-transplant outcomes, including all-cause hospitalization and mortality.

CONCLUSIONS

GLS demonstrates allograft LV systolic dysfunction in donors and recipients not detected by LVEF. The clinical implications of subclinical allograft dysfunction detected by LV GLS require further study.

Cardiac transplantation for older patients: Characteristics and outcomes in the septuagenarian population

BACKGROUND

With increasing age of patients with heart failure, it is important to understand the potential role for orthotopic heart transplant (OHT) in elderly patients. We examined recipient and donor characteristics and long-term outcomes of older recipients of OHT in the United States.

METHODS

Using the United Network for Organ Sharing database, we identified OHT recipients from the years 1987-2014 and stratified them by age 18-59 years old, 60-69 years old, and ≥70 years old. We compared baseline characteristics of recipients and donors and assessed outcomes across groups.

RESULTS

During this period, 50,432 patients underwent OHT; 71.8% (n = 36,190) were 18-59 years old, 26.8% (n = 13,527) were 60-69 years old, and 1.4% (n = 715) were ≥70 years old. Comparing the ≥70 years old group and 60-69 years old group, older patients had higher rates of ischemic etiology (53.6% vs 44.9%) and baseline renal dysfunction (61.4% vs 56.4%) and at the time of OHT were less likely to be currently hospitalized (45.0% vs 50.9%) or supported with left ventricular assist device therapy (21.0% vs 28.3%). Older recipients received organs from older donors (median age 36 years old vs 30 years old) who were more likely to have diabetes and substance use. After OHT, the median length of stay was similar between groups. At 1 year, of patients alive, patients ≥70 years old had fewer rejection episodes (17.8%) compared with patients 60-69 years old (29.5%). The 5-year mortality was 26.9% for recipients 18-59 years old, 29.3% for recipients 60-69 years old, and 30.8% for recipients ≥70 years old.

CONCLUSIONS

Despite advanced age and less ideal donors, OHT recipients in their 70s had similar outcomes to recipients in their 60s. Selected older patients should not routinely be excluded from consideration for OHT.

Comparison of 2-Year Outcomes of Extended Criteria Cardiac Transplantation Versus Destination Left Ventricular Assist Device Therapy Using Continuous Flow

Alternatives have emerged for patients ineligible for cardiac transplantation under standard criteria. The purpose of our study was to compare outcomes in patients ineligible for cardiac transplantation under standard criteria, treated either with extended criteria cardiac transplantation (ECCT) or a continuous flow destination therapy left ventricular assist device (CF DT-LVAD). From 2005 to 2012, patients treated with either ECCT or CF DT-LVAD at our institution were retrospectively analyzed. In the overall unmatched cohort, we examined mortality and other outcomes, including index hospitalization length of stay, renal function, stroke, and readmission rates. After propensity score (PS) matching, outcomes were compared between ECCT and CF DT-LVAD recipients. Overall, 62 patients underwent ECCT, and 146 patients were treated with CF DT-LVAD. The 2-year mortality estimate for ECCT recipients was 27.3% (95% confidence interval 15.5% to 39.1%) and for CF DT-LVAD recipients was 11.2% (95% confidence interval 4.8% to 17.6%). After PS matching of 39 patients from each treatment group, there was no significant difference in overall survival after 2 years (p = 0.346). In both unmatched and PS-matched analyses, CF DT-LVAD patients compared with ECCT had a significantly higher estimated glomerular filtration rate at 1 year but also had significantly higher hospital readmission rates. Stroke also more commonly occurred after CF DT-LVAD compared with ECCT (17 vs 5, unmatched; and 2 vs 1, PS matched). However, there was no significant difference between PS-matched groups in 2-year stroke-free survival (p = 0.371). In conclusion, ECCT and CF DT-LVAD in select patients are comparable therapies with respect to 2-year survival.

Donor Heart Utilization following Cardiopulmonary Arrest and Resuscitation: Influence of Donor Characteristics and Wait Times in Transplant Regions

Background. Procurement of hearts from cardiopulmonary arrest and resuscitated (CPR) donors for transplantation is suboptimal. We studied the influences of donor factors and regional wait times on CPR donor heart utilization. Methods. From UNOS database (1998 to 2012), we identified 44,744 heart donors, of which 4,964 (11%) received CPR. Based on procurement of heart for transplantation, CPR donors were divided into hearts procured (HP) and hearts not procured (HNP) groups. Logistic regression analysis was used to identify predictors of heart procurement. Results. Of the 4,964 CPR donors, 1,427 (28.8%) were in the HP group. Donor characteristics that favored heart procurement include younger age (25.5 ± 15 yrs versus 39 ± 18 yrs, P ≤ 0.0001), male gender (34% versus 23%, P ≤ 0.0001), shorter CPR duration (<15 min versus >30 min, P ≤ 0.0001), and head trauma (60% versus 15%). Among the 11 UNOS regions, the highest procurement was in Region 1 (37%) and the lowest in Region 3 (24%). Regional transplant volumes and median waiting times did not influence heart procurement rates. Conclusions. Only 28.8% of CPR donor hearts were procured for transplantation. Factors favoring heart procurement include younger age, male gender, short CPR duration, and traumatic head injury. Heart procurement varied by region but not by transplant volumes or wait times.