Primary graft dysfunction after heart transplantation: Incidence, trends, and associated risk factors

Donation After Circulatory Death Heart Transplantation: A Narrative Review

Heart transplantation is the definitive treatment for refractory, end-stage heart failure. The number of patients awaiting transplantation far exceeds available organs. In an effort to expand the donor pool, donation after circulatory death (DCD) heart transplantation has garnered renewed interest. Unlike donation after brain death, DCD donors do not meet the criteria for brain death and are dependent on life-sustaining therapies. Procurement can include a direct strategy or a normothermic regional perfusion, whereby there is restoration of perfusion to the organ before explantation. There are new developments in cold storage and ex vivo perfusion strategies. Since its inception, there has been a steady improvement in post-transplant outcomes, largely attributed to advancements in operative and procurement strategies. In this narrative review, the authors address the unique considerations of DCD heart transplantation, including withdrawal of care, the logistics of procuring and resuscitating organs, outcomes compared with standard donation after brain death, and ethical considerations.

Donation After Circulatory Death Heart Transplant: Current State and Future Directions

Orthotopic heart transplant is the gold standard therapeutic intervention for patients with end-stage heart failure. Conventionally, heart transplant has relied on donation after brain death for organ recovery. Donation after circulatory death (DCD) is the donation of the heart after confirming that circulatory function has irreversibly ceased. DCD-orthotopic heart transplant differs from donation after brain death-orthotopic heart transplant in ways that carry implications for widespread adoption, including differences in organ recovery, storage and ethical considerations surrounding normothermic regional perfusion with DCD. Despite these differences, DCD has shown promising early outcomes, augmenting the donor pool and allowing more individuals to benefit from orthotopic heart transplant. This review aims to present the current state and future trajectory of DCD-heart transplant, examine key differences between DCD and donation after brain death, including clinical experiences and innovations in methodologies, and address the ongoing ethical challenges surrounding the new frontier in heart transplant with DCD donors.

Long-distance donor heart procurement using an innovative cold static storage system

The global lack of donor shortage poses a major limitation for heart transplantation. New concepts with expanded donor inclusion criteria comprise extended transport distances and prolonged ischemic times with the aim of reaching a larger number of potential donors. Recent developments in cold storage solutions may allow more donor hearts with prolonged ischemic times to be use for transplantation in the future. We present our experience during a long-distance donor heart procurement with the longest reported transport distance and transport time in the current literature. This was made possible through the use of SherpaPak™, an innovative cold storage system which allows for controlled temperatures during transportation.

Impact of controlled hypothermic preservation on outcomes following heart transplantation

BACKGROUND

Severe primary graft dysfunction (PGD) is a major cause of early mortality after heart transplant, but the impact of donor organ preservation conditions on severity of PGD and survival has not been well characterized.

METHODS

Data from US adult heart-transplant recipients in the Global Utilization and Registry Database for Improved Heart Preservation-Heart Registry (NCT04141605) were analyzed to quantify PGD severity, mortality, and associated risk factors. The independent contributions of organ preservation method (traditional ice storage vs controlled hypothermic preservation) and ischemic time were analyzed using propensity matching and logistic regression.

RESULTS

Among 1,061 US adult heart transplants performed between October 2015 and December 2022, controlled hypothermic preservation was associated with a significant reduction in the incidence of severe PGD compared to ice (6.6% [37/559] vs 10.4% [47/452], p = 0.039). Following propensity matching, severe PGD was reduced by 50% (6.0% [17/281] vs 12.1% [34/281], respectively; p = 0.018). The Kaplan-Meier terminal probability of 1-year mortality was 4.2% for recipients without PGD, 7.2% for mild or moderate PGD, and 32.1%, for severe PGD (p < 0.001). The probability of severe PGD increased for both cohorts with longer ischemic time, but donor hearts stored on ice were more likely to develop severe PGD at all ischemic times compared to controlled hypothermic preservation.

CONCLUSIONS

Severe PGD is the deadliest complication of heart transplantation and is associated with a 7.8-fold increase in probability of 1-year mortality. Controlled hypothermic preservation significantly attenuates the risk of severe PGD and is a simple yet highly effective tool for mitigating post-transplant morbidity.

Primary graft dysfunction in heart transplantation: the challenge to survival

Primary graft dysfunction (PGD) is a life-threatening clinical condition with a high mortality rate, presenting as left, right, or biventricular dysfunction within the initial 24 h following heart transplantation, in the absence of a discernible secondary cause. Given its intricate nature, definitive definition and diagnosis of PGD continues to pose a challenge. The pathophysiology of PGD encompasses numerous underlying mechanisms, some of which remain to be elucidated, including factors like myocardial damage, the release of proinflammatory mediators, and the occurrence of ischemia-reperfusion injury. The dynamic characteristics of both donors and recipients, coupled with the inclination towards marginal lists containing more risk factors, together contribute to the increased incidence of PGD. The augmentation of therapeutic strategies involving mechanical circulatory support accelerates myocardial recovery, thereby significantly contributing to survival. Nonetheless, a universally accepted treatment algorithm for the swift management of this clinical condition, which necessitates immediate intervention upon diagnosis, remains absent. This paper aims to review the existing literature and shed light on how diagnosis, pathophysiology, risk factors, treatment, and perioperative management affect the outcome of PGD.

Early Outcomes in Patients With LVAD Undergoing Heart Transplant via Use of the SherpaPak Cardiac Transport System

BACKGROUND

Heart transplant (HT) in recipients with left ventricular assist devices (LVADs) is associated with poor early post-HT outcomes, including primary graft dysfunction (PGD). As complicated heart explants in recipients with LVADs may produce longer ischemic times, innovations in donor heart preservation may yield improved post-HT outcomes. The SherpaPak Cardiac Transport System is an organ preservation technology that maintains donor heart temperatures between 4 °C and 8 °C, which may minimize ischemic and cold-induced graft injuries. This analysis sought to identify whether the use of SherpaPak versus traditional cold storage was associated with differential outcomes among patients with durable LVAD undergoing HT.

METHODS

Global Utilization and Registry Database for Improved Heart Preservation-Heart (NCT04141605) is a multicenter registry assessing post-HT outcomes comparing 2 methods of donor heart preservation: SherpaPak versus traditional cold storage. A retrospective review of all patients with durable LVAD who underwent HT was performed. Outcomes assessed included rates of PGD, post-HT mechanical circulatory support use, and 30-day and 1-year survival.

RESULTS

SherpaPak (n=149) and traditional cold storage (n=178) patients had similar baseline characteristics. SherpaPak use was associated with reduced PGD (adjusted odds ratio, 0.56 [95% CI, 0.32-0.99]; P=0.045) and severe PGD (adjusted odds ratio, 0.31 [95% CI, 0.13-0.75]; P=0.009), despite an increased total ischemic time in the SherpaPak group. Propensity matched analysis also noted a trend toward reduced intensive care unit (SherpaPak 7.5±6.4 days versus traditional cold storage 11.3±18.8 days; P=0.09) and hospital (SherpaPak 20.5±11.9 days versus traditional cold storage 28.7±37.0 days; P=0.06) lengths of stay. The 30-day and 1-year survival was similar between groups.

CONCLUSIONS

SherpaPak use was associated with improved early post-HT outcomes among patients with LVAD undergoing HT. This innovation in preservation technology may be an option for HT candidates at increased risk for PGD.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04141605.

Epidemiology of perioperative RV dysfunction: risk factors, incidence, and clinical implications

In this edition of the journal, the Perioperative Quality Initiative (POQI) present three manuscripts describing the physiology, assessment, and management of right ventricular dysfunction (RVD) as pertains to the perioperative setting. This narrative review seeks to provide context for these manuscripts, discussing the epidemiology of perioperative RVD focussing on definition, risk factors, and clinical implications. Throughout the perioperative period, there are many potential risk factors/insults predisposing to perioperative RVD including pre-existing RVD, fluid overload, myocardial ischaemia, pulmonary embolism, lung injury, mechanical ventilation, hypoxia and hypercarbia, lung resection, medullary reaming and cement implantation, cardiac surgery, cardiopulmonary bypass, heart and lung transplantation, and left ventricular assist device implantation. There has however been little systematic attempt to quantify the incidence of perioperative RVD. What limited data exists has assessed perioperative RVD using echocardiography, cardiovascular magnetic resonance, and pulmonary artery catheterisation but is beset by challenges resulting from the inconsistencies in RVD definitions. Alongside differences in patient and surgical risk profile, this leads to wide variation in the incidence estimate. Data concerning the clinical implications of perioperative RVD is even more scarce, though there is evidence to suggest RVD is associated with atrial arrhythmias and prolonged length of critical care stay following thoracic surgery, increased need for inotropic support in revision orthopaedic surgery, and increased critical care requirement and mortality following cardiac surgery. Acute manifestations of RVD result from low cardiac output or systemic venous congestion, which are non-specific to the diagnosis of RVD. As such, RVD is easily overlooked, and the relative contribution of RV dysfunction to postoperative morbidity is likely to be underestimated.We applaud the POQI group for highlighting this important condition. There is undoubtedly a need for further study of the RV in the perioperative period in addition to solutions for perioperative risk prediction and management strategies. There is much to understand, study, and trial in this area, but importantly for our patients, we are increasingly recognising the importance of these uncertainties.

Artificial Intelligence Approaches for Predicting the Risks of Durable Mechanical Circulatory Support Therapy and Cardiac Transplantation

Background: The use of AI-driven technologies in probing big data to generate better risk prediction models has been an ongoing and expanding area of investigation. The AI-driven models may perform better as compared to linear models; however, more investigations are needed in this area to refine their predictability and applicability to the field of durable MCS and cardiac transplantation. Methods: A literature review was carried out using Google Scholar/PubMed from 2000 to 2023. Results: This review defines the knowledge gaps and describes different AI-driven approaches that may be used to further our understanding. Conclusions: The limitations of current models are due to missing data, data imbalances, and the uneven distribution of variables in the datasets from which the models are derived. There is an urgent need for predictive models that can integrate a large number of clinical variables from multicenter data to account for the variability in patient characteristics that influence patient selection, outcomes, and survival for both durable MCS and HT; this may be fulfilled by AI-driven risk prediction models.

Recipient Outcomes With Extended Criteria Donors Using Advanced Heart Preservation: An Analysis of the GUARDIAN-Heart Registry

BACKGROUND

The prevalence of end-stage heart failure and patients who could benefit from heart transplantation requires an expansion of the donor pool, relying on the transplant community to continually re-evaluate and expand the use of extended criteria donor organs. Introduction of new technologies such as the Paragonix SherpaPak Cardiac Transport System aids in this shift. We seek to analyze the impact of the SherpaPak system on recipient outcomes who receive extended criteria organs in the GUARDIAN-Heart Registry.

METHODS

Between October 2015 and December 2022, 1,113 adults from 15 US centers receiving donor hearts utilizing either SherpaPak (n = 560) or conventional ice storage (ice, n = 453) were analyzed from the GUARDIAN-Heart Registry using summary statistics. A previously published set of criteria was used to identify extended criteria donors, which included 193 SherpaPak and 137 ice.

RESULTS

There were a few baseline differences among recipients in the 2 cohorts; most notably, IMPACT scores, distance traveled, and total ischemic time were significantly greater in SherpaPak, and significantly more donor hearts in the SherpaPak cohort had >4 hours total ischemia time. Posttransplant mechanical circulatory support utilization (SherpaPak 22.3% vs ice 35.0%, p = 0.012) and new extracorporeal membrane oxygenation/ventricular assist device (SherpaPak 7.8% vs ice 15.3%, p = 0.033) was significantly reduced, and the rate of severe primary graft dysfunction (SherpaPak 6.2% vs ice 13.9%, p = 0.022) was significantly reduced by over 50% in hearts preserved using SherpaPak. One-year survival between cohorts was similar (SherpaPak 92.9% vs ice 89.6%, p = 0.27).

CONCLUSIONS

This subgroup analysis demonstrates that SherpaPak can be safely used to utilize extended criteria donors with low severe PGD rates.

Increasing Utilization of Extended Criteria Donor Hearts for Transplantation: The OCS Heart EXPAND Trial

BACKGROUND

Extended criteria donor (ECD) hearts available with donation after brain death (DBD) are underutilized for transplantation due to limitations of cold storage.

OBJECTIVES

This study evaluated use of an extracorporeal perfusion system on donor heart utilization and post-transplant outcomes in ECD DBD hearts.

METHODS

In this prospective, single-arm, multicenter study, adult heart transplant recipients received ECD hearts using an extracorporeal perfusion system if hearts met study criteria. The primary outcome was a composite of 30-day survival and absence of severe primary graft dysfunction (PGD). Secondary outcomes were donor heart utilization rate, 30-day survival, and incidence of severe PGD. The safety outcome was the mean number of heart graft-related serious adverse events within 30 days. Additional outcomes included survival through 2 years benchmarked to concurrent nonrandomized control subjects.

RESULTS

A total of 173 ECD DBD hearts were perfused; 150 (87%) were successfully transplanted; 23 (13%) did not meet study transplantation criteria. At 30 days, 92% of patients had survived and had no severe PGD. The 30-day survival was 97%, and the incidence of severe PGD was 6.7%. The mean number of heart graft-related serious adverse events within 30 days was 0.17 (95% CI: 0.11-0.23). Patient survival was 93%, 89%, and 86% at 6, 12, and 24 months, respectively, and was comparable with concurrent nonrandomized control subjects.

CONCLUSIONS

Use of an extracorporeal perfusion system resulted in successfully transplanting 87% of donor hearts with excellent patient survival to 2 years post-transplant and low rates of severe PGD. The ability to safely use ECD DBD hearts could substantially increase the number of heart transplants and expand access to patients in need. (International EXPAND Heart Pivotal Trial [EXPANDHeart]; NCT02323321; Heart EXPAND Continued Access Protocol; NCT03835754).

Hypothermic oxygenated perfusion (HOPE) safely and effectively extends acceptable donor heart preservation times: Results of the Australian and New Zealand trial

BACKGROUND

Cold static storage preservation of donor hearts for periods longer than 4 hours increases the risk of primary graft dysfunction (PGD). The aim of the study was to determine if hypothermic oxygenated perfusion (HOPE) could safely prolong the preservation time of donor hearts.

METHODS

We conducted a nonrandomized, single arm, multicenter investigation of the effect of HOPE using the XVIVO Heart Preservation System on donor hearts with a projected preservation time of 6 to 8 hours on 30-day recipient survival and allograft function post-transplant. Each center completed 1 or 2 short preservation time followed by long preservation time cases. PGD was classified as occurring in the first 24 hours after transplantation or secondary graft dysfunction (SGD) occurring at any time with a clearly defined cause. Trial survival was compared with a comparator group based on data from the International Society of Heart and Lung Transplantation (ISHLT) Registry.

RESULTS

We performed heart transplants using 7 short and 29 long preservation time donor hearts placed on the HOPE system. The mean preservation time for the long preservation time cases was 414 minutes, the longest being 8 hours and 47 minutes. There was 100% survival at 30 days. One long preservation time recipient developed PGD, and 1 developed SGD. One short preservation time patient developed SGD. Thirty day survival was superior to the ISHLT comparator group despite substantially longer preservation times in the trial patients.

CONCLUSIONS

HOPE provides effective preservation out to preservation times of nearly 9 hours allowing retrieval from remote geographic locations.

A phantom for targeted endomyocardial biopsy training

Endomyocardial biopsy (EMB) of the right ventricular (RV) septal surface during cardiac catheterization is the standard method to assess cardiac allograft rejection, heart failure, or inflammatory cardiomyopathies. We developed methodology using a three-dimensional (3D) printed phantom to provide proof of concept for using biplane overlay technology for targeted EMB. A standard bioptome and steerable sheath were used to discern feasibility of biopsy for seven regions of the RV septum guided by 3D overlay. This novel biopsy phantom can help train operators in biopsy techniques, and biplane overlay technology has the potential to advance targeted EMB in transplant and cardiomyopathy populations.

The Role of Recipient Thyroid Hormone Supplementation in Primary Graft Dysfunction After Heart Transplantation: A Propensity-Adjusted Analysis

OBJECTIVES

To investigate whether recipient administration of thyroid hormone (liothyronine [T3]) is associated with reduced rates of primary graft dysfunction (PGD) after orthotopic heart transplantation.

DESIGN

Retrospective cohort study.

SETTING

Single-center, university hospital.

PARTICIPANTS

Adult patients undergoing orthotopic heart transplantation.

INTERVENTIONS

A total of 609 adult heart transplant recipients were divided into 2 cohorts: patients who did not receive T3 (no T3 group, from 2009 to 2014), and patients who received T3 (T3 group, from 2015 to 2019). Propensity-adjusted logistic regression was performed to assess the association between T3 supplementation and PGD.

MEASUREMENTS AND MAIN RESULTS

After applying exclusion criteria and propensity-score analysis, the final cohort included 461 patients. The incidence of PGD was not significantly different between the groups (33.9% no T3 group v 40.8% T3 group; p = 0.32). Mortality at 30 days (3% no T3 group v 2% T3 group; p = 0.53) and 1 year (10% no T3 group v 12% T3 group; p = 0.26) were also not significantly different. When assessing the severity of PGD, there were no differences in the groups' rates of moderate PGD (not requiring mechanical circulatory support other than an intra-aortic balloon pump) or severe PGD (requiring mechanical circulatory support other than an intra-aortic balloon pump). However, segmented time regression analysis revealed that patients in the T3 group were less likely to develop severe PGD.

CONCLUSIONS

These findings indicated that recipient single-dose thyroid hormone administration may not protect against the development of PGD, but may attenuate the severity of PGD.

A Paradigm Shift in Heart Preservation: Improved Post-transplant Outcomes in Recipients of Donor Hearts Preserved With the SherpaPak System

Traditional ice storage has been the historic standard for preserving donor's hearts. However, this approach provides variability in cooling, increasing risks of freezing injury. To date, no preservation technology has been reported to improve survival after transplantation. The Paragonix SherpaPak Cardiac Transport System (SCTS) is a controlled hypothermic technology clinically used since 2018. Real-world evidence on clinical benefits of SCTS compared to conventional ice cold storage (ICS) was evaluated. Between October 2015 and January 2022, 569 US adults receiving donor hearts preserved and transported either in SCTS (n = 255) or ICS (n = 314) were analyzed from the Global Utilization And Registry Database for Improved heArt preservatioN (GUARDIAN-Heart) registry. Propensity matching and a subgroup analysis of >240 minutes ischemic time were performed to evaluate comparative outcomes. Overall, the SCTS cohort had significantly lower rates of severe primary graft dysfunction (PGD) ( p = 0.03). When propensity matched, SCTS had improving 1-year survival ( p = 0.10), significantly lower rates of severe PGD ( p = 0.011), and lower overall post-transplant MCS utilization ( p = 0.098). For patients with ischemic times >4 hours, the SCTS cohort had reduced post-transplant MCS utilization ( p = 0.01), reduced incidence of severe PGD ( p = 0.005), and improved 30-day survival ( p = 0.02). A multivariate analysis of independent risk factors revealed that compared to SCTS, use of ice results in a 3.4-fold greater chance of severe PGD ( p = 0.014). Utilization of SCTS is associated with a trend toward increased post-transplant survival and significantly lower severe PGD and MCS utilization. These findings fundamentally challenge the decades-long status quo of transporting donor hearts using ice.

Inhaled Epoprostenol Compared With Nitric Oxide for Right Ventricular Support After Major Cardiac Surgery

BACKGROUND

Right ventricular failure (RVF) is a leading driver of morbidity and death after major cardiac surgery for advanced heart failure, including orthotopic heart transplantation and left ventricular assist device implantation. Inhaled pulmonary-selective vasodilators, such as inhaled epoprostenol (iEPO) and nitric oxide (iNO), are essential therapeutics for the prevention and medical management of postoperative RVF. However, there is limited evidence from clinical trials to guide agent selection despite the significant cost considerations of iNO therapy.

METHODS

In this double-blind trial, participants were stratified by assigned surgery and key preoperative prognostic features, then randomized to continuously receive either iEPO or iNO beginning at the time of separation from cardiopulmonary bypass with the continuation of treatment into the intensive care unit stay. The primary outcome was the composite RVF rate after both operations, defined after transplantation by the initiation of mechanical circulatory support for isolated RVF, and defined after left ventricular assist device implantation by moderate or severe right heart failure according to criteria from the Interagency Registry for Mechanically Assisted Circulatory Support. An equivalence margin of 15 percentage points was prespecified for between-group RVF risk difference. Secondary postoperative outcomes were assessed for treatment differences and included: mechanical ventilation duration; hospital and intensive care unit length of stay during the index hospitalization; acute kidney injury development including renal replacement therapy initiation; and death at 30 days, 90 days, and 1 year after surgery.

RESULTS

Of 231 randomized participants who met eligibility at the time of surgery, 120 received iEPO, and 111 received iNO. Primary outcome occurred in 30 participants (25.0%) in the iEPO group and 25 participants (22.5%) in the iNO group, for a risk difference of 2.5 percentage points (two one-sided test 90% CI, -6.6% to 11.6%) in support of equivalence. There were no significant between-group differences for any of the measured postoperative secondary outcomes.

CONCLUSIONS

Among patients undergoing major cardiac surgery for advanced heart failure, inhaled pulmonary-selective vasodilator treatment using iEPO was associated with similar risks for RVF development and development of other postoperative secondary outcomes compared with treatment using iNO.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03081052.

Perioperative Management of Heart Transplantation: A Clinical Review

In this clinical review, the authors summarize the perioperative management of heart transplant patients with a focus on hemodynamics, immunosuppressive strategies, hemostasis and hemorrage, and the prevention and treatment of infectious complications.

Health care resource utilization and clinical outcomes for adult heart transplant recipients with primary graft dysfunction

INTRODUCTION

The advent of new technologies to reduce primary graft dysfunction (PGD) and improve outcomes after heart transplantation are costly. Adoption of these technologies requires a better understanding of health care utilization, specifically the costs related to PGD.

METHODS

Records were examined from all adult patients who underwent orthotopic heart transplantation (OHT) between July 1, 2013 and July 30, 2019 at a single institution. Total costs were categorized into variable, fixed, direct, and indirect costs. Patient costs from time of transplantation to hospital discharge were transformed with the z-score transformation and modeled in a linear regression model, adjusted for potential confounders and in-hospital mortality. The quintile of patient costs was modeled using a proportional odds model, adjusted for confounders and in-hospital mortality.

RESULTS

359 patients were analyzed, including 142 with PGD and 217 without PGD. PGD was associated with a .42 increase in z-score of total patient costs (95% CI: .22-.62; p < .0001). Additionally, any grade of PGD was associated with a 2.95 increase in odds for a higher cost of transplant (95% CI: 1.94-4.46, p < .0001). These differences were substantially greater when PGD was categorized as severe. Similar results were obtained for fixed, variable, direct, and indirect costs.

CONCLUSIONS

PGD after OHT impacts morbidity, mortality, and health care utilization. We found that PGD after OHT results in a significant increase in total patient costs. This increase was substantially higher if the PGD was severe.

SUMMARY

Primary graft dysfunction after heart transplantation impacts morbidity, mortality, and health care utilization. PGD after OHT is costly and investments should be made to reduce the burden of PGD after OHT to improve patient outcomes.

Heart transplantation as a rescue strategy for patients with refractory electrical storm

AIMS

Heart transplantation (HT) can be proposed as a therapeutic strategy for patients with severe refractory electrical storm (ES). Data in the literature are scarce and based on case reports. We aimed at determining the characteristics and survival of patients transplanted for refractory ES.

METHODS AND RESULTS

Patients registered on HT waiting list during the following days after ES and eventually transplanted, from 2010 to 2021, were retrospectively included in 11 French centres. The primary endpoint was in-hospital mortality. Forty-five patients were included [82% men; 55.0 (47.8-59.3) years old; 42.2% and 26.7% non-ischaemic dilated or ischaemic cardiomyopathies, respectively]. Among them, 42 (93.3%) received amiodarone, 29 received (64.4%) beta blockers, 19 (42.2%) required deep sedation, 22 had (48.9%) mechanical circulatory support, and 9 (20.0%) had radiofrequency catheter ablation. Twenty-two patients (62%) were in cardiogenic shock. Inscription on wait list and transplantation occurred 3.0 (1.0-5.0) days and 9.0 (4.0-14.0) days after ES onset, respectively. After transplantation, 20 patients (44.4%) needed immediate haemodynamic support by extracorporeal membrane oxygenation (ECMO). In-hospital mortality rate was 28.9%. Predictors of in-hospital mortality were serum creatinine/urea levels, need for immediate post-operative ECMO support, post-operative complications, and surgical re-interventions. One-year survival was 68.9%.

CONCLUSION

Electrical storm is a rare indication of HT but may be lifesaving in those patients presenting intractable arrhythmias despite usual care. Most patients can be safely discharged from hospital, although post-operative mortality remains substantial in this context of emergency transplantation. Larger studies are warranted to precisely determine those patients at higher risk of in-hospital mortality.

Introduction of machine perfusion of donor hearts in a single center in Germany

Introduction

Organ shortage, subsequent use of extended donor criteria organs and high-risk recipients needing redo-surgery are increasing the complexity of heart transplantation. Donor organ machine perfusion (MP) is an emerging technology allowing reduction of ischemia time as well as standardized evaluation of the organ. The aim of this study was to review the introduction of MP and analyze the results of heart transplantation after MP in our center.

Methods

In a retrospective single-center study, data from a prospectively collected database were analysed. From July 2018 to August 2021, fourteen hearts were retrieved and perfused using the Organ Care System (OCS), 12 hearts were transplanted. Criteria to use the OCS were based on donor/recipient characteristics. Primary objective was 30-day survival, secondary objectives were major cardiac adverse events, graft function, rejection episodes as well as overall survival in the follow-up and assessment of MP technical reliability.

Results

All patients survived the procedure and the postoperative 30-day interval. No MP related complications were noted. Graft ejection fraction beyond 14 days was ≥ 50% in all cases. Endomyocardial biopsy showed excellent results with no or mild rejection. Two donor hearts were rejected after OCS perfusion and evaluation.

Conclusion

Ex vivo normothermic MP during organ procurement is a safe and promising technique to expand the donor pool. Reduction of cold ischemic time while providing additional donor heart assessment and reconditioning options increased the number of acceptable donor hearts. Additional clinical trials are necessary to develop guidelines regarding the application of MP.

Transplantation Outcomes with Donor Hearts after Circulatory Death

BACKGROUND

Data showing the efficacy and safety of the transplantation of hearts obtained from donors after circulatory death as compared with hearts obtained from donors after brain death are limited.

METHODS

We conducted a randomized, noninferiority trial in which adult candidates for heart transplantation were assigned in a 3:1 ratio to receive a heart after the circulatory death of the donor or a heart from a donor after brain death if that heart was available first (circulatory-death group) or to receive only a heart that had been preserved with the use of traditional cold storage after the brain death of the donor (brain-death group). The primary end point was the risk-adjusted survival at 6 months in the as-treated circulatory-death group as compared with the brain-death group. The primary safety end point was serious adverse events associated with the heart graft at 30 days after transplantation.

RESULTS

A total of 180 patients underwent transplantation; 90 (assigned to the circulatory-death group) received a heart donated after circulatory death and 90 (regardless of group assignment) received a heart donated after brain death. A total of 166 transplant recipients were included in the as-treated primary analysis (80 who received a heart from a circulatory-death donor and 86 who received a heart from a brain-death donor). The risk-adjusted 6-month survival in the as-treated population was 94% (95% confidence interval [CI], 88 to 99) among recipients of a heart from a circulatory-death donor, as compared with 90% (95% CI, 84 to 97) among recipients of a heart from a brain-death donor (least-squares mean difference, -3 percentage points; 90% CI, -10 to 3; P<0.001 for noninferiority [margin, 20 percentage points]). There were no substantial between-group differences in the mean per-patient number of serious adverse events associated with the heart graft at 30 days after transplantation.

CONCLUSIONS

In this trial, risk-adjusted survival at 6 months after transplantation with a donor heart that had been reanimated and assessed with the use of extracorporeal nonischemic perfusion after circulatory death was not inferior to that after standard-care transplantation with a donor heart that had been preserved with the use of cold storage after brain death. (Funded by TransMedics; ClinicalTrials.gov number, NCT03831048.).

Donor Pericardial Interleukin and Apolipoprotein Levels May Predict the Outcome after Human Orthotopic Heart Transplantation

The proinflammatory cascade that is activated at the time of brain death plays a crucial role in organ procurement. Our aim of this study was to explore the relationship between the clinical outcome of orthotopic heart transplantation, as well as cytokine and apolipoprotein profiles of the pericardial fluid obtained at donation. Interleukin, adipokine and lipoprotein levels in the pericardial fluid, as well as clinical data of twenty donors after brain death, were investigated. Outcome variables included primary graft dysfunction, the need for posttransplantation mechanical cardiac support and International Society for Heart and Lung Transplantation grade ≥ 2R rejection. Hormone management and donor risk scores were also investigated. Lower levels of IL-6 were observed in primary graft dysfunction (median: 36.72 [IQR: 19.47–62.90] versus 183.67 [41.21–452.56]; p = 0.029) and in the need for mechanical cardiac support (44.12 [20.12–85.70] versus 247.13 [38.51–510.38]; p = 0.043). Rejection was associated with lower ApoAII (p = 0.021), ApoB100 (p = 0.032) and ApoM levels (p = 0.025). Lower adipsin levels were detected in those patients receiving desmopressin (p = 0.037); moreover, lower leptin levels were found in those patients receiving glucocorticoid therapy (p = 0.045), and higher T3 levels were found in those patients treated with L-thyroxine (p = 0.047) compared to those patients not receiving these hormone replacement therapies. IL-5 levels were significantly associated with UNOS-D score (p = 0.004), Heart Donor Score (HDS) and Adapted HDS (p < 0.001). The monitoring of immunological and metabolic changes in donors after brain death may help in the prediction of potential complications after heart transplantation, thus potentially optimizing donor heart allocation.

Metabolic reprogramming by immune-responsive gene 1 up-regulation improves donor heart preservation and function

Preservation quality of donor hearts is a key determinant of transplant success. Preservation duration beyond 4 hours is associated with primary graft dysfunction (PGD). Given transport time constraints, geographical limitations exist for donor-recipient matching, leading to donor heart underutilization. Here, we showed that metabolic reprogramming through up-regulation of the enzyme immune response gene 1 (IRG1) and its product itaconate improved heart function after prolonged preservation. Irg1 transcript induction was achieved by adding the histone deacetylase (HDAC) inhibitor valproic acid (VPA) to a histidine-tryptophan-ketoglutarate solution used for donor heart preservation. VPA increased acetylated H3K27 occupancy at the IRG1 enhancer and IRG1 transcript expression in human donor hearts. IRG1 converts aconitate to itaconate, which has both anti-inflammatory and antioxidant properties. Accordingly, our studies showed that Irg1 transcript up-regulation by VPA treatment increased nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) in mice, which was accompanied by increased antioxidant protein expression [hemeoxygenase 1 (HO1) and superoxide dismutase 1 (SOD1)]. Deletion of Irg1 in mice (Irg1^-/-) negated the antioxidant and cardioprotective effects of VPA. Consistent with itaconate's ability to inhibit succinate dehydrogenase, VPA treatment of human hearts increased itaconate availability and reduced succinate accumulation during preservation. VPA similarly increased IRG1 expression in pig donor hearts and improved its function in an ex vivo cardiac perfusion system both at the clinical 4-hour preservation threshold and at 10 hours. These results suggest that augmentation of cardioprotective immune-metabolomic pathways may be a promising therapeutic strategy for improving donor heart function in transplantation.

State of the art - Extracorporeal membrane oxygenation as a bridge to thoracic transplantation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has revolutionized the treatment of refractory cardiac and respiratory failure, and its use continues to increase, particularly in adults. However, ECMO-related morbidity and mortality remain high.

MAIN TEXT

In this review, we investigate and expand upon the current state of the art in thoracic transplant and extracorporeal life support (ELS). In particular, we examine recent increase in incidence of heart transplant in patients supported by ECMO; the potential changes in patient care and selection for transplant in the years prior to updated United Network for Organ Sharing (UNOS) organ allocation guidelines versus those in the years following, particularly where these guidelines pertain to ECMO; and the newly revived practice of heart-lung block transplants (HLT) and the prevalence and utility of ECMO support in patients listed for HLT.

CONCLUSIONS

Our findings highlight encouraging outcomes in patients bridged to transplant with ECMO, considerable changes in treatment surrounding the updated UNOS guidelines, and complex, diverse outcomes among different centers in their care for increasingly ill patients listed for thoracic transplant.

Severe primary graft dysfunction of the heart transplant is associated with increased plasma and intragraft proinflammatory cytokine expression

INTRODUCTION

Heart transplant results have constantly improved but primary left ventricle graft dysfunction (LV-PGD) remains a devastating complication early after transplantation. Donor and recipient systemic inflammatory response may be involved in immune activation of the transplant, and LV-PGD development. Here, we investigated donor and recipient plasma and intragraft cytokine profiles preoperatively and during LV-PGD and searched for predictive markers for LV-PGD.

METHODS

Donor and recipient plasma samples (n = 74) and myocardial biopsies of heart transplants (n = 64) were analyzed. Plasma and intragraft cytokine levels were determined by multiplexed and next-generation sequencing platforms, respectively. The development of LV-PGD during the first 24 hours, and graft function and mortality up to 1 year after transplantation, were examined.

RESULTS

Severe LV-PGD, but not mild or moderate LV-PGD, was significantly associated with early mortality, plasma high-sensitivity troponin elevation, and an increase in intragraft and plasma proinflammatory cytokines during reperfusion. Preoperative donor and recipient plasma cytokine levels failed to predict LV-PGD. Cytokine network analysis identified interleukins -6, -8, -10, and -18 as key players during reperfusion. Prolonged cold and total ischemia time, and increased need for red blood cell transfusions during operation were identified as clinical risk factors for severe LV-PGD.

CONCLUSIONS

Severe LV-PGD was associated with a poor clinical outcome. Donor and recipient plasma cytokine profile failed to predict LV-PGD, but severe LV-PGD was associated with an increase in post-reperfusion intragraft and recipient plasma proinflammatory cytokines. Identified key cytokines may be potential therapeutic targets to improve early and long-term outcomes after heart transplantation.

Primary isolated right ventricular failure after heart transplantation: prevalence, right ventricular characteristics, and outcomes

To determine the prevalence, right ventricular (RV) characteristics, and outcomes of primary isolated RV failure (PI-RVF) after heart transplant (HTX). PI-RVF was defined as (1) the need for mechanical circulatory support post-transplant, or (2) evidence of RVF post-transplant as measured by right atrial pressure (RAP) > 15 mmHg, cardiac index of < 2.0 L/min/m² or inotrope support for < 72 h, pulmonary capillary wedge pressure < 18 mmHg, and transpulmonary gradient < 15 mmHg with pulmonary systolic pressure < 50 mmHg. PI-RVF can be diagnosed from the first 24-72 h after completion of heart transplantation. A total of 122 consecutive patients who underwent HTX were reviewed. Of these, 11 were excluded because of secondary causes of graft dysfunction (GD). PI-RVF was present in 65 of 111 patients (59%) and 31 (48%) met the criteria for PGD-RV. Severity of patients with PI-RVF included 41(37%) mild, 14 (13%) moderate, and 10 (9%) severe. The median onset of PI-RVF was 14 (0-49) h and RV recovery occurred 5 (3-14) days after HTX. Severe RV failure was a predictor of 30-day mortality (HR 13.2, 95% CI 1.6-124.5%, p < 0.001) and post-transplant dialysis (HR 6.9, 95% CI 2.0-257.4%, p = 0.001). Patients with moderate PI-RVF had a higher rate of 30-day mortality (14% vs. 0%, p = 0.014) and post-operative dialysis (21% vs. 2%, p = 0.016) than those with mild PI-RVF. Among patients with mild and moderate PI-RVF, patients who did not meet the criteria of PGD-RV had worsening BUN/creatinine than those who met the PGD-RV criteria (p < 0.05 for all). PI-RVF was common and can occur after 24 h post-HTX. The median RV recovery time was 5 (2-14) days after HTX. Severe PI-RVF was associated with increased rates of 30-day mortality and post-operative dialysis. Moderate PI-RVF was also associated with post-operative dialysis. A revised definition of PGD-RV may be needed since patients who had adverse outcomes did not meet the criteria of PGD-RV.

Review of Postoperative Care for Heart Transplant Recipients

The early postoperative management strategies after heart transplantation include optimizing the function of the denervated heart, correcting the causes of hemodynamic instability, and initiating and maintaining immunosuppressive therapy, allograft rejection surveillance, and prophylaxis against infections caused by immunosuppression. The course of postoperative support is influenced by the quality of allograft myocardial protection prior to implantation and reperfusion, donor-recipient heart size matching, surgical technique of orthotopic heart transplantation, and patient factors (eg, preoperative condition, immunologic compatibility, postoperative vasomotor tone, severity and reversibility of pulmonary vascular hypertension, pulmonary function, mediastinal blood loss, and end-organ perfusion). This review provides an overview of the early postoperative care of recipients and includes a brief description of the surgical techniques for orthotopic heart transplantation.

Primary heart dysfunction is greater with combined heart and lung compared with isolated heart procurement

OBJECTIVE

Combined heart and lungs (CHL) procurement differs from isolated heart (IH) procurement in several aspects, including lung recruitment, cannulation, and preservation requirements. We aimed to investigate whether CHL versus IH procurement contributes to the development of primary graft dysfunction (PGD) after heart transplantation (HT).

METHODS

Between 1999 and 2019, we assessed 175 patients undergoing HT at a single center. Patients were divided into IH (n = 61) or CHL (n = 114) procurement groups. End points included PGD (defined according to the International Society for Heart and Lung Transplantation consensus statement) and long-term survival.

RESULTS

The incidence of PGD was significantly greater in CHL recipients compared with IH recipients (53.5% vs 16.4%, P < .001). Multivariable analysis showed that CHL procurement was independently associated with a significant 4.6-fold increased risk for PGD (95% confidence interval, 2.1-11, P < .001). Univariable and multivariable analyses showed that the overall survival was not significantly affected by the procurement group (log-rank P = .150, hazard ratio, 1.13; 95% confidence interval, 0.68-1.88, P = .646). The simultaneous procurement of abdominal organs was not associated with an increased risk of PGD in HT recipients. These results remained consistent in a propensity-matched analysis.

CONCLUSIONS

Combined procurement of heart and lungs is independently associated with an increased risk of PGD. Further prospective studies are needed to validate this hypothesis-generating study.

Improved Outcomes in Severe Primary Graft Dysfunction After Heart Transplantation Following Donation After Circulatory Death Compared With Donation After Brain Death

BACKGROUND

Primary graft dysfunction (PGD), the leading cause of early mortality after heart transplantation, is more common following donation after circulatory death (DCD) than donation after brain death (DBD). We conducted a single-center, retrospective cohort study to compare the incidence, severity and outcomes of patients experiencing PGD after DCD compared to DBD heart transplantation.

METHODS AND RESULTS

Medical records were reviewed for all adult heart transplant recipients at our institution between March 2016 and December 2021. PGD was diagnosed within 24 hours after transplant according to modified International Society for Heart and Lung Transplant criteria. A total of 459 patients underwent isolated heart transplantation during the study period, 65 (14%) following DCD and 394 (86%) following DBD. The incidence of moderate or severe PGD in DCD and DBD recipients was 34% and 23%, respectively (P = 0.070). DCD recipients were more likely to experience severe biventricular PGD than DBD recipients (19% vs 7.4%; P = 0.004). Among patients with severe PGD, DCD recipients experienced shorter median (Q1, Q3) duration of post-transplant mechanical circulatory support (6 [4, 7] vs 9 [5, 14] days; P = 0.039), shorter median post-transplant hospital length of stay (17 [15, 29] vs 52 [26, 83] days; P = 0.004), and similar 60-day survival rates (100% [95% CI: 76.8%-100%] vs 80.0% [63.1%-91.6%]; P = 0.17) and overall survival (log-rank; P = 0.078) compared with DBD recipients.

CONCLUSIONS

DCD heart transplant recipients were more likely to experience severe, biventricular PGD than DBD recipients. Despite this, DCD recipients with severe PGD spent fewer days on mechanical circulatory support and in the hospital than similar DBD patients. These findings suggest that patterns of graft dysfunction and recovery may differ between donor types, and they support the expansion of the heart-donor pool with DCD.

Optimizing Anastomoses Technique in Orthotopic Heart Transplantation: Comparison of Biatrial, Bicaval and Modified Bicaval Technique

Implantation techniques for orthotopic heart transplantation (HTx) have evolved over the centuries. Recently new approaches of modified bicaval techniques to minimize warm ischemia are gaining popularity in the literature. Between 2010 and 2022 n = 238 patients underwent HTx in our department. The recipients were retrospectively reviewed and divided regarding their anastomoses’ technique. Anastomoses were sutured either in biatrial (n = 37), bicaval (n = 191) or in a modified bicaval (n = 10) manner with suturing of the superior cava vein and A. pulmonalis anastomosis after removing the aortic cross-clamp during the reperfusion. Warm ischemia was 62 ± 11 min for biatrial, 66 ± 15 min for bicaval, but only 48 ± 10 min for modified bicaval technique (p < 0.001). The incidence of severe primary graft dysfunction (PGD) was comparable between biatrial (27.0%) and bicaval (28.8%) anastomoses. In contrast, in patients with modified bicaval technique PGD occurred only in a single patient (10.0%). The incidence of postoperative pacemaker implantation was 18.2% for biatrial compared to 3.0% for bicaval and 0.0% for modified bicaval technique (p = 0.01). The modified bicaval technique enables to decrease the crucial warm ischemia during HTx compared to both biatrial and regular bicaval techniques. Therefore, we strongly recommend bicaval anastomoses, ideally in a modified manner.

Multicenter Registry Using Propensity Score Analysis to Compare a Novel Transport/Preservation System to Traditional Means on Postoperative Hospital Outcomes and Costs for Heart Transplant Patients

The standard method for cardiac allograft preservation for the past 50 years has been static storage using crushed ice. A heart transplant transportation system designed to improve preservation quality with temperature monitoring, the Paragonix SherpaPak Cardiac Transport System (SCTS), was evaluated for its impact on postoperative costs relative to conventional ice storage. Observational US multicenter registry data collected during the August 2015 to November 2021 timeframe from 12 transplant hospitals were analyzed using logistic regression analysis and propensity matching to balance measured baseline covariates and to reduce selection bias. Hospital cost and outcome data post-transplant were then evaluated using various statistical methods. One hundred seventy-four (174) patients were identified resulting in 87 matches. Baseline characteristics were similar between groups. The SCTS group had a significantly lower proportion of ICU days on post-transplant mechanical circulatory support (p < 0.0001); significantly fewer patients on extracorporeal membrane oxygenation (p = 0.017); and significantly fewer patients experiencing severe primary graft dysfunction (PGD) (p = 0.03). Overall hospital plus mechanical circulatory support post-transplant costs were significantly lower by $26.7K in the CTS cohort (p = 0.03). Use of the SCTS is associated with improved clinical outcomes resulting in significantly lower overall hospital care costs.

Clinicopathological correlations in heart transplantation recipients complicated by death or re-transplantation

Purpose

This study aimed to identify and correlate pathological findings with clinical outcomes in patients after orthotopic heart transplantation (OHT) who either died or underwent a re-transplantation.

Methodology and study design

Single-center retrospective analysis of primary OHT patients who died or were re-transplanted between October 2012 and July 2021. Clinical data were matched with corresponding pathological findings from endomyocardial biopsies on antibody-mediated rejection, cellular rejection, and cardiac allograft vasculopathy. Re-assessment of available tissue samples was performed to investigate acute myocardial injury (AMI) as a distinct phenomenon. These were correlated with clinical outcomes, which included severe primary graft dysfunction. Patients were grouped according to the presence of AMI and compared.

Results

We identified 47 patients with truncated outcomes after the first OHT. The median age was 59 years, 36 patients (76%) were male, 25 patients (53%) had a prior history of cardiac operation, and 21 patients (45%) were supported with a durable assist device before OHT. Of those, AMI was identified in 22 (47%) patients (AMI group), and 25 patients had no AMI (non-AMI group). Groups were comparable in baseline and perioperative data. Histopathological observations in AMI group included a non-significant higher incidence of antibody-mediated rejection Grade 1 or higher (pAMR ≥ 1) (32% vs. 12%, P = 0.154), and non-significant lower incidence of severe acute cellular rejection (ACR ≥ 2R) (32% vs. 40%, P = 0.762). Clinical observations in the AMI group found a significantly higher occurrence of severe primary graft dysfunction (68% vs. 20%, P = 0.001) and a highly significant shorter duration from transplantation to death or re-transplantation (42 days [IQR 26, 120] vs. 1,133 days [711–1,664], P < 0.0001). Those patients had a significantly higher occurrence of cardiac-related deaths (64% vs. 24%, P = 0.020). No difference was observed in other outcomes.

Conclusion

In heart transplant recipients with a truncated postoperative course leading to either death or re-transplantation, AMI in endomyocardial biopsies was a common pathological phenomenon, which correlated with the clinical occurrence of severe primary graft dysfunction. Those patients had significantly shorter survival times and higher cardiac-related deaths. The presence of AMI suggests a truncated course after OHT.

Predicted heart mass for size matching in obese heart transplant donors and recipients

INTRODUCTION

Predicted heart mass (PHM) was neither derived nor evaluated in an obese population. Our objective was to evaluate size mismatch using actual body weight or IBW-adjusted PHM on mortality and risk assessment.

METHODS

We conducted a retrospective cohort study of adult recipients with BMI ≥30 kg/m² or recipients of donors with BMI≥30 kg/m² from the ISHLT registry. We used multivariable Cox proportional hazard models to evaluate 30 day and 1-year mortality. The 2 models were compared using net reclassification index.

RESULTS

10,817 HT recipients, age 55 (IQR 46-62) years, 23% female, BMI 31 kg/m² (IQR 28-33) were included. Donors were age 34 (IQR 24-44) years, 31% female, and BMI 31 kg/m² (IQR 26-34). There was a significant non-linear association between mortality and actual PHM but not IBW-adjusted PHM. Undersizing using actual PHM was associated with higher 30-day and 1-year mortality (p<0.01), not seen with IBW-adjusted PHM. Actual PHM better risk classified 0.6% (95% CI 0.3-0.8%) patients compared to IBW-adjusted PHM.

CONCLUSION

Actual PHM can be used for size matching when assessing mortality risk in obese recipients or recipients of obese donors. There is no advantage to re-calculating PHM using IBW to define candidate risk at the time of organ allocation. This article is protected by copyright. All rights reserved.

Residual Pulmonary Vascular Resistance Increase Under Left Ventricular Assist Device Support Predicts Long-Term Cardiac Function After Heart Transplantation

Aims

We compared hemodynamics and clinical events after heart transplantation (HTx) in patients stratified by the severity of residual pulmonary vascular resistance (PVR) after left ventricular assist device (LVAD) implantation for bridge to transplantation.

Methods

We retrospectively analyzed patients who had undergone HTx at the University of Tokyo Hospital. We defined the high PVR group as patients with PVR of >3 Wood Units (WU) as measured by right heart catheterization performed 1 month after LVAD implantation.

Results

We included 85 consecutive HTx recipients, 20 of whom were classified in the high PVR group and 65 in the low PVR group. The difference in PVR between the two groups became apparent at 2 years after HTx (the high PVR group: 1.77 ± 0.41 WU, the low PVR group: 1.24 ± 0.59 WU, p = 0.0009). The differences in mean pulmonary artery pressure (mPAP), mean right arterial pressure (mRAP), and mean pulmonary capillary wedge pressure (mPCWP) tended to increase from the first year after HTx, and were all significantly higher in the high PVR group at 3 years after HTx (mPAP: 22.7 ± 9.0 mm Hg vs. 15.4 ± 4.3 mm Hg, p = 0.0009, mRAP: 7.2 ± 3.6 mm Hg vs. 4.1 ± 2.1 mm Hg, p = 0.0042, and mPCWP: 13.4 ± 4.5 mm Hg, 8.8 ± 3.3 mm Hg, p = 0.0040). In addition, pulmonary artery pulsatility index was significantly lower in the high PVR group than in the low PVR group at 3 years after HTx (2.51 ± 1.00 vs. 5.21 ± 3.23, p = 0.0033). The composite event including hospitalization for heart failure, diuretic use, and elevated intracardiac pressure (mRAP ≥ 12 mm Hg or mPCWP ≥ 18 mm Hg) between the two groups was significantly more common in the high PVR group. Residual high PVR was still an important predictor (hazard ratio 6.5, 95% confidence interval 2.0–21.6, and p = 0.0023) after multivariate Cox regression analysis.

Conclusion

Our study demonstrates that patients with residual high PVR under LVAD implantation showed the increase of right and left atrial pressure in the chronic phase after HTx.

Packing the donor heart: Is SherpaPak cold preservation technique safer compared to ice cold storage

INTRODUCTION

The present study aimed to compare the clinical outcomes of heart transplant patients whose donor hearts were preserved with the SherpaPak controlled cold organ system versus the conventional ice storage technique.

METHODS

All patients undergoing heart transplantation at our center between January 2019 and April 2021 were divided into two groups according to the technique used during donor heart preservation and transport. The first group consisted of 34 SherpaPak controlled temperature preservation patients, and the second group consisted of 47 patients where the conventional three bags and ice technique was utilized during organ transportation. The two groups were compared based on demographics, operative details, and postoperative outcomes.

RESULTS

There were no significant differences between the groups regarding Vasoactive Inotropic Score (VIS), Primary Graft Dysfunction (PGD), and the need for a transient pacer. However, the VIS, PGD, and pacing trends were lower in the SherpaPak patients even though the total ischemic and cardiopulmonary bypass times were significantly longer. Furthermore, SherpaPak patients exhibited a shorter stay in the ICU with no severe PGD and mortality.

CONCLUSION

The SherpaPak donor heart preservation provides safe outcomes in heart transplant patients. Further research is needed to utilize this method for longer durations of ischemic time and expand travel distances for organ transportation. This article is protected by copyright. All rights reserved.

Determining optimal donor heart ischemic times in adult cardiac transplantation

Objectives

Unsupervised statistical determination of optimal allograft ischemic time (IT) on heart transplant outcomes among ABO donor heart types.

Methods

We identified 36,145 heart transplants (2000–2018) from the United Network for Organ Sharing database. Continuous and categorical variables were analyzed with parametric and nonparametric testing. Determination of IT cutoffs for survival analysis was performed using Contal and O'Quigley univariable method and Vito Muggeo multivariable segmented modeling.

Results

Univariable and multivariable IT threshold determination revealed a cutoff at about 3 h. The hourly increase in survival risk with ≥3 h IT is asymmetrically experienced at the early 90 days (hazard ratio [HR] = 1.29, p < .001) and up to 1‐year time point (HR = 1.16, p < .001). Beyond 1 year the risk of prolonged IT is less impactful (HR = 1.04, p = .022). Longer IT was associated with more postoperative complications such as stroke (2.7% vs. 2.3, p = .042), dialysis (11.6% vs. 9.1%, p < .001) and death from primary graft dysfunction (1.8% vs. 1.2%, p < .001). O blood type donor hearts with IT ≥ 3 h has significantly increased hourly mortality risk at 90 days (HR = 1.27, p < .001), 90 days to 1 year (HR = 1.22, p < .001) and >1 year (HR = 1.05, p = .041). For non‐O blood types with ≥3 h IT hourly mortality risk was increased at 90 days (HR = 1.33, p < .001), but not at 90 days to 1 year (HR = 1.09, p = .146) nor ≥1 year (HR = 1.08, p = .237).

Conclusions

The donor heart IT threshold for survival determined from unbiased statistical modeling occurs at 3 h. With longer preservation times, transplantation with O donor hearts was associated with worse survival.

Thrombus formation in the noncoronary sinus of Valsalva following primary graft dysfunction

We hereby present a case of thrombus formation in the noncoronary sinus of Valsalva following primary graft dysfunction. The case highlights that stagnant and nonpulsatile flow can form thrombi in the noncoronary sinus since this sinus does not have a natural distal runoff.

Plasma Levels of SERCA2a as a Noninvasive Biomarker of Primary Graft Dysfunction After Heart Transplantation

BACKGROUND

Noninvasive detection of primary graft dysfunction (PGD) remains a major challenge. SERCA2a plays an important role in cardiac homeostasis and its dysregulation has been associated with ventricular dysfunction and rejection. This study aimed to determine the potential utility of plasma levels of SERCA2a as a biomarker of PGD.

METHODS

One hundred thirty-five plasma samples were collected from adult recipients 2-6 hours before heart transplantation (HT). Plasma concentrations of SERCA2a were determined using a specific sandwich ELISA. Variables related to the recipient, the donor, and the periprocedural were collected to determine a multivariate predictive model of PGD.

RESULTS

Levels of SERCA2a were decreased in patients who developed PGD (median 0.430 ng/mL [interquartile range, 0.260-0.945] versus 0.830 ng/mL [interquartile range, 0.582-1.052]; P = 0.001). Receiver operating characteristic curve analysis revealed that SERCA2a discriminated between patients with and without PGD (AUC = 0.682; P = 0.001), and a cutoff point ≥ 0.60 ng/mL was a protective independent predictor of PGD (odds ratio 0.215 [P = 0.004]). Three independent predictors of PGD in this study were reduced levels of pre-HT SERCA2a, increased bilirubin levels, and short-term mechanical circulatory support bridge to transplantation. The analysis of the receiver operating characteristic curve of the model obtained a significant AUC 0.788, P = 0.0001.

CONCLUSIONS

Our findings suggest that assessment of SERCA2a plasma levels may improve risk prediction for the occurrence of PGD and could be considered as a novel noninvasive biomarker in patients undergoing HT.

Primary Graft Dysfunction in Heart Transplant Recipients-Risk Factors and Longitudinal Outcomes

Before the 33rd Annual International Society for Heart and Lung Transplantation conference, there was significant intercenter variability in definitions of primary graft dysfunction (PGD). The incidence, risk factors, and outcomes of consensus-defined PGD warrant further investigation. We retrospectively examined 448 adult cardiac transplant recipients at our institution from 2005 to 2017. Patient and procedural characteristics were compared between PGD cases and controls. Multivariable logistic regression was used to model PGD and immediate postoperative high-inotrope requirement for hypothesized risk factors. Patients were followed for a mean 5.3 years to determine longitudinal mortality. The incidence of PGD was 16.5%. No significant differences were found with respect to age, sex, race, body mass index, predicted heart mass mismatch, pretransplant amiodarone therapy, or pretransplant mechanical circulatory support (MCS) between recipients with PGD versus no PGD. Each 10 minute increase in ischemic time was associated with 5% greater odds of PGD (OR = 1.05 [95% CI, 1.00-1.10]; p = 0.049). Pretransplant MCS, predicted heart mass mismatch ≥30%, and pretransplant amiodarone therapy were associated with high-immediate postoperative inotropic requirement. The 30 day, 1 year, and 5 year mortality for patients with PGD were 28.4%, 38.0%, and 45.8%, respectively, compared with 1.9%, 7.1%, and 21.5% for those without PGD (log-rank, p < 0.0001). PGD heralded high 30 day, 1 year, and 5 year mortality. Pretransplant MCS, predicted heart mass mismatch, and amiodarone exposure were associated with high-inotrope requirement, while prolonged ischemic time and multiple perioperative transfusions were associated with consensus-defined PGD, which may have important clinical implications under the revised United Network for Organ Sharing allocation system.

Long-term effects of primary graft dysfunction after heart transplantation

BACKGROUND

We studied the incidence of primary graft dysfunction (PGD), its impact on in-hospital and follow-up outcomes and searched for independent risk factors.

METHODS

During an 18-year period, 508 individuals underwent heart transplantation at our institution. Patients were diagnosed with none, mild, moderate or severe PGD according to ISHLT criteria.

RESULTS

Thirty-eight patients (7.5%) met the ISHLT criteria for mild PGD, 92 (18.1%) for moderate PGD and 23 (4.5%) for severe PGD. Patients were classified into none/mild PGD (77.4%) and moderate/severe PGD (22.6%) groups. In-hospital mortality was 12.4% (7.8% for none/mild PGD and 28.7% for moderate/severe PGD; p < .001). Survival at 1, 5, and 15 years was 85.5 ± 1.9% versus 67.2 ± 4.5%, 80 ± 2.2% versus 63.5 ± 4.7%, and 60.4 ± 3.6% versus 45.9 ± 8.4%, respectively (p < .001). Excluding the events occurring during the first month of follow-up, survival was comparable between the two groups (93.1 ± 1.4% vs. 94.7 ± 2.6 at 1 year and 65.6 ± 3.8% vs. 70.4 ± 10.4% at 15 years, respectively; p = .88). Upon multivariate logistic regression analysis preoperative mechanical circulatory support (odds ratio [OR] = 5.86) and preoperative intra-aortic balloon pump (IABP) (OR = 9.58) were independently associated with moderate/severe PGD.

CONCLUSIONS

Our results confirm that PGD is associated with poor in-hospital outcome. The poor outcome does not extend beyond the first month of follow-up, with comparable survival between patients with none/mild PGD and moderate/severe PGD in the short and long-term. Mechanical circulatory support and preoperative IABP were found to be independent risk factors for moderate/severe PGD.

The Interaction of Amiodarone and Continuous-flow Left Ventricular Assist Device Use in Risk of Severe Primary Graft Dysfunction Following Heart Transplantation

Supplemental Digital Content is available in the text.

Background.

Primary graft dysfunction (PGD) increases morbidity and mortality after heart transplant. Here we investigated (1) the association of continuous-flow left ventricular assist device (CF-LVAD), amiodarone, and severe PGD and (2) the safety of amiodarone discontinuation in CF-LVAD patients.

Methods.

Retrospective, single-center study of heart transplant recipients was conducted to investigate the association of risk factors and severe PGD. Patients were grouped into 4 groups based on the presence (denoted +) or absence (denoted –) of amiodarone and CF-LVAD. Prospective amiodarone discontinuation was undertaken to investigate its safety in a cohort of CF-LVAD patients. Study endpoints were severe PGD and recurrence of arrhythmia.

Results.

Severe PGD was strongly associated with CF-LVAD and amiodarone use, and its prevalence is highest if both risk factors were present (CF-LVAD–/amiodarone – 1.5%, CF-LVAD –/amiodarone+ 4.5%, CF-LVAD+/amiodarone – 7.1%, CF-LVAD+/amiodarone+ 21.8%; P < 0.01). The product of every 1-y additional CF-LVAD support by every 100 mg amiodarone was associated with severe PGD (adjusted odds ratio, 1.43; 95% confidence interval, 1.15-1.78; P < 0.01). Amiodarone was prospectively discontinued in 28 CF-LVAD patients. Of them, 6 patients had recurrence of arrhythmia requiring treatment or heart failure admission. There were no deaths. Nine patients in whom amiodarone had been discontinued had heart transplants with no severe PGD.

Conclusions.

Amiodarone and CF-LVAD were independently associated with severe PGD. The combination of both risk factors was associated with a higher prevalence of severe PGD. Amiodarone discontinuation was associated with recurrence of arrhythmia in 6 CF-LVAD patients. There was no mortality associated with amiodarone discontinuation.

Impact of pretransplant left ventricular assist device support duration on outcome after heart transplantation

 

OBJECTIVES

Heart transplantation after left ventricular assist device (LVAD) implantation remains challenging. It is still unclear whether its support duration impacts the outcome after transplantation.

METHODS

All patients undergoing heart transplantation between 2010 and 2021 at a single department after previous left ventricular assistance were retrospectively reviewed and divided into 4 different study groups with regard to the duration of LVAD support to examine the impact on the postoperative morbidity and mortality.

RESULTS

A total of n = 198 patients were included and assigned to the 4 study groups (group 1: <90 days, n = 14; group 2: 90 days to 1 year, n = 31; group 3: 1–2 years, n = 29; group 4: >2 years, n = 24). Although there were no differences between the 4 groups concerning relevant mismatch between the recipients and donors, the incidence of primary graft dysfunction was numerically increased in patients with the shortest support duration, and also those patients with >1 year of support (group 1: 35.7%, group 2: 25.8%, group 3: 41.4%, group 4: 37.5%, P = 0.63). The incidence of acute graft rejection was by trend increased in patients of group 1 (group 1: 28.6%, group 2: 3.3%, group 3: 7.1%, group 4: 12.5%, P = 0.06). Duration of LVAD support did not impact on perioperative adverse events (infections, P = 0.79; acute kidney injury, P = 0.85; neurological events, P = 0.74; thoracic bleeding, P = 0.61), neither on postoperative survival (1-year survival: group 1: 78.6%, group 2: 66.7%, group 3: 80.0%, group 4: 72.7%, P = 0.74).

CONCLUSION

We cannot identify a significant impact of the duration of pretransplant LVAD support on postoperative outcome; therefore, we cannot recommend a certain timeframe for transplantation of LVAD patients.

Geographic disparities in heart transplantation persist under the new allocation policy

BACKGROUND

This study evaluated the impact of the 2018 heart allocation policy change on geographic disparities in United States orthotopic heart transplantation (OHT).

METHODS

The United Network for Organ Sharing registry was queried to measure geographic disparity in OHT rates between pre-policy and post-policy change eras. We performed multilevel Poisson regression to measure region-level OHT rates. We derived an allocation priority-adjusted median incidence rate ratio (MIRR) for each policy era, a measure of median change in OHT rates between regions.

RESULTS

5958.78 waitlist person-years were analyzed, comprising 6596 OHT procedures (3890 pre-policy and 2706 post-policy). Median region-level OHT rate was .94 transplants/person-years before and 1.51 transplants/person-years after the policy change (P < .001). The unadjusted OHT MIRR across regions was 1.29 (95% CI 1.00-1.50) pre-policy change and 1.17 (95% CI 1.00-1.43) post-policy change, suggesting that the region-related variance in OHT rates decreased under the new allocation. After adjustment for allocation priority risk factors, the MIRR pre-policy change was 1.13 (95% CI 1.01-1.32) and post-policy change was 1.15 (95% CI 1.00-1.35).

CONCLUSIONS

Geography accounts for ∼10% of the disparity among United States OHT rates. Despite broader heart sharing, the updated allocation policy did not substantially alter the existing geographic disparities among OHT recipients.

Contemporary contribution of cardiac surgery for the treatment of cardiomyopathies and pericardial diseases

Cardiomyopathy refers to a spectrum of heterogeneous myocardial disorders characterized by morphological and structural alterations leading eventually to heart failure, by affecting cardiac filling and/or the cardiac systolic function. Heart transplantation is currently the gold standard surgical treatment for patients with heart failure, with a median survival in adults of 12 years according to international registries. However, the limited available donor pool does not allow its extensive employment. For this reason, mechanical circulatory supports are increasingly used, and in the short term are becoming as possible alternatives to heart transplantation, owing to improved technologies and increased biocompatibility. However, long-term outcomes of mechanical assist devices are still burdened with a high rate of adverse events. Conventional surgical treatments could be still considered as alternatives to heart replacement treatment when tailored both on patient clinical conditions and etiology of cardiac diseases. In particular, among patients affected by ischemic cardiomyopathy, coronary artery bypass grafting has proven to improve survival when associated to optimal medical treatment, and surgical ventricular restoration might be considered as a valid treatment in particular cases. Correction of functional mitral valve regurgitation by mitral annuloplasty, which aims to restore left ventricular geometry, has not demonstrated unambiguous results, and outcomes of this procedure are still controversial. Pericardial pathology becomes of surgical interest when it is responsible for a reduced filling capacity of the heart chambers, which can develop acutely (cardiac tamponade) or chronically (as in the case of constrictive pericarditis). This review focuses on the different surgical approaches that could be adopted to treat patients with heart failure and pericardial diseases.

Post-transplant inotrope score is associated with clinical outcomes after adult heart transplantation

BACKGROUND

Inotrope score has been proposed as a marker of clinical outcome after adult heart transplantation (HTx) but is rarely used in practice.

METHODS

Inotrope score during the first 48 h after HTx was calculated in 81 patients as: dopamine + dobutamine + amrinone + milrinone (dose × 15) + epinephrine (dose × 100) + norepinephrine (dose × 100) + enoximone + isoprenaline (dose × 100), with each drug in µg/kg/min. Determinants of inotrope score were identified with linear regression. Cox regression was used to determine the association of inotrope score with mortality.

RESULTS

The mean recipient age was 52 ± 11 years, and 32 (39.5%) patients were female. Determinants of inotrope score were preoperative C-reactive protein, serum urea, congenital heart disease, and donor cardiac arrest (R2  = .30). Inotrope score was associated with 5-year mortality, independent of recipient age and gender (HR 1.03, 95% CI 1.00-1.07). This association was attenuated when adjusting for female-to-male transplant and ischemia time. Inotrope score was also strongly associated with continuous veno-venous hemofiltration (OR 1.07, 95% CI 1.03-1.12).

CONCLUSION

High inotrope score post-HTx was observed in recipient congenital heart disease and was associated with a higher risk of mortality and acute kidney injury.