Search Results (13)

The growing disparity between the demand for donor hearts and their availability has reignited interest in donation after circulatory death (DCD) heart transplantation. Historically, DCD heart transplantation has been overshadowed by donation after brain death (DBD) due to ethical and preservation challenges. However, recent advancements in procurement techniques allow for evaluation of the donor heart and enable the broader utilization of DCD donors. While challenges remain, early outcomes suggest comparable survival rates between DCD and DBD heart transplantation. This review provides a comprehensive overview of the historical evolution, current practices, and future directions of DCD heart transplantation. Here, we emphasize its potential to expand the heart donor pool and alleviate the organ shortage crisis. Full article

Heart failure persists as a critical public health challenge, with heart transplantation esteemed as the optimal treatment for patients with end-stage heart failure. However, the limited availability of donor hearts presents a major obstacle to meeting patient needs. In recent years, the most groundbreaking progress in heart transplantation has been in donor heart procurement, significantly expanding the donor pool and enhancing clinical outcomes. This review comprehensively examines these advancements, including the resurgence of heart donation after circulatory death and innovative recovery and evaluation technologies such as normothermic machine perfusion and thoraco-abdominal normothermic regional perfusion. Additionally, novel preservation methods, including controlled hypothermic preservation and hypothermic oxygenated perfusion, are evaluated. The review also explores the use of extended-criteria donors, post-cardiopulmonary resuscitation donors, and high-risk donors, all contributing to increased donor availability without compromising outcomes. Future directions, such as xenotransplantation, biomarkers, and artificial intelligence in donor heart evaluation and procurement, are discussed. These innovations promise to address current limitations and optimize donor heart utilization, ultimately enhancing transplantation success. By identifying recent advancements and proposing future research directions, this review aims to provide insights into advancing heart transplantation and improving patient outcomes. Full article

Heart transplantation with donation after circulatory death (DCD) provides excellent patient outcomes and increases donor heart availability. However, unlike conventional grafts obtained through donation after brain death, DCD cardiac grafts are not only exposed to warm, unprotected ischemia, but also to a potentially damaging pre-ischemic phase after withdrawal of life-sustaining therapy (WLST). In this review, we aim to bring together knowledge about changes in cardiac energy metabolism and its regulation that occur in DCD donors during WLST, circulatory arrest, and following the onset of warm ischemia. Acute metabolic, hemodynamic, and biochemical changes in the DCD donor expose hearts to high circulating catecholamines, hypoxia, and warm ischemia, all of which can negatively impact the heart. Further metabolic changes and cellular damage occur with reperfusion. The altered energy substrate availability prior to organ procurement likely plays an important role in graft quality and post-ischemic cardiac recovery. These aspects should, therefore, be considered in clinical protocols, as well as in pre-clinical DCD models. Notably, interventions prior to graft procurement are limited for ethical reasons in DCD donors; thus, it is important to understand these mechanisms to optimize conditions during initial reperfusion in concert with graft evaluation and re-evaluation for the purpose of tailoring and adjusting therapies and ensuring optimal graft quality for transplantation. Full article

The current understanding of the safety of heart transplantation from COVID-19+ donors is uncertain. Preliminary studies suggest that heart transplants from these donors may be feasible. We analyzed 1-year outcomes in COVID-19+ donor heart recipients using 1:3 propensity matching. The OPTN database was queried for adult heart transplant recipients between 1 January 2020 and 30 September 2022. COVID-19+ donors were defined as those who tested positive on NATs or antigen tests within 21 days prior to procurement. Multiorgan transplants, retransplants, donors without COVID-19 testing, and recipients allocated under the old heart allocation system were excluded. A total of 7211 heart transplant recipients met the inclusion criteria, including 316 COVID-19+ donor heart recipients. Further, 290 COVID-19+ donor heart recipients were matched to 870 COVID-19− donor heart recipients. Survival was similar between the groups at 30 days (p = 0.46), 6 months (p = 0.17), and 1 year (p = 0.07). Recipients from COVID-19+ donors in the matched cohort were less likely to experience postoperative acute rejection prior to discharge (p = 0.01). National COVID-19+ donor heart usage varied by region: region 11 transplanted the most COVID-19+ hearts (15.8%), and region 6 transplanted the fewest (3.2%). Our findings indicate that COVID-19+ heart transplantation can be performed with safe early outcomes. Further analyses are needed to determine if long-term outcomes are equivalent between groups. Full article

Cold preservation is a key component to organ procurement and transplantation. Cold preservation functions by slowing metabolic activity of procured organs and begins the period known as cold ischemic time (CIT). Reducing CIT and warm ischemic time (WIT) are paramount to minimizing donor organ damage from ischemia and the build-up of waste products and signals that drive reperfusion injury prior to transplantation into a matching recipient. Preventing damage from CIT and WIT and extending the amount of time that organs can tolerate has been a major goal of organ transplantation since donors and recipients are frequently not located within the same hospital, region, or state. Meanwhile, the amount of CIT that a transplant center is willing to accept differs based on the organ, the institution receiving the organ offer, and the doctor receiving the offer for that institution. With the introduction of a partial heart transplantation conducted last year at Duke University, it is important to discuss how much CIT transplant centers conducting a partial heart transplantation (pHT) are willing to accept. This article will review the physiology of WIT and CIT, associated organ damage, CIT variation among transplant centers and organ types, and provide a brief discussion of the future of pHT-accepted CIT and the need for research in this field. Full article

Introduction: The COVID-19 pandemic and consequent social isolation prompted a surge in mental health disorders and substance use in the general population and, therefore, in potential organ donors. We aimed to evaluate if this led to a change in donor characteristics, including the mechanism and circumstance of death, and how this may have affected clinical outcomes following heart transplantation. Methods: We identified all heart donors from the SRTR database between 18 October 2018 and 31 December 2021, excluding those who donated immediately after the US national emergency declaration. Donors were stratified into pre-COVID-19 (Pre-Cov; through 12 March 2020) and post-COVID-19 national emergency declaration cohorts (Post-Cov; 1 August 2020 through 31 December 2021) based on the heart procurement date. Relevant demographics, cause of death, and substance use history were collected in addition to graft cold ischemic time, the incidence of primary graft dysfunction (PGD), and recipient survival at 30 days post-transplant. Results: A total of 10,314 heart donors were identified; 4941 were stratified into the Pre-Cov and 5373 into the Post-Cov cohorts. There was no difference in demographics, but illicit drug use was significantly higher in the Post-Cov group, leading to an increased incidence of death from drug intoxication. Fatal gunshot wounds were also more common. Despite these changes, the incidence of PGD remained similar (p = 0.371), and there was no difference in 30 days recipient survival (p = 0.545). Conclusion: Our findings confirm that COVID-19 had a major impact on mental health and psychosocial life with an associated increase in illicit substance use and fatal intoxication rates in heart transplant donors. These changes did not alter peri-operative mortality following heart transplantation. Future studies are needed to ensure that long-term outcomes remain unaffected. Full article

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. Full article

As heart transplantation continues to be the gold-standard therapy for end-stage heart failure, the supply-demand imbalance of available organs worsens. Until recently, there have been no advances in increasing the donor pool, as prolonged cold ischemic time excludes the use of certain donors. The TransMedics Organ Care System (OCS) allows for ex-vivo normothermic perfusion, which allows for a reduction of cold ischemic time and allows for long-distance procurements. Furthermore, the OCS allows for real-time monitoring and assessment of allograft quality, which can be crucial for extended-criteria donors or donation after cardiac death (DCD) donors. Conversely, the XVIVO device allows for hypothermic perfusion to preserve allografts. Despite their limitations, these devices have the potential to alleviate the supply-demand imbalance in donor availability. Full article

Both particular myocardial locations in the human heart and the canonical transient receptor potential 6 (TRPC6) cation channel have been linked with cardiac pathophysiologies. Thus, the present study mapped TRPC6-protein distribution in select anatomic locations associated with cardiac disease in the context of an orienting pathological assessment. Specimens were obtained from 5 body donors (4 formalin fixation, 1 nitrite pickling salt-ethanol-polyethylene glycol (NEP) fixation; median age 81 years; 2 females) and procured for basic histological stains and TRPC6-immunohistochemistry. The latter was analyzed descriptively regarding distribution and intensity of positive signals. The percentage of positively labelled myocardium was also determined (optical threshold method). Exclusively exploratory statistical analyses were performed. TRPC6-protein was distributed widespread and homogenously within each analyzed sample. TRPC6-immunoreactive myocardial area was comparable regarding the different anatomic regions and sex. A significantly larger area of TRPC6-immunoreactive myocardium was found in the NEP-fixed donor compared to the formalin fixed donors. Two donors with more severe heart disease showed smaller areas of myocardial TRPC6-immunoreactivity overall compared to the other 3 donors. In summary, in the elderly, TRPC6-protein is widely and homogenously distributed, and severe cardiac disease might be associated with less TRPC6-immunoreactive myocardial area. The tissue fixation method represents a potential confounder. Full article

Heart transplantation has become the accepted treatment for advanced heart failure, with over 4000–5000 performed in the world annually. Although the number of yearly transplants performed has been increasing over the last decade, the number of candidates in need of transplantation continues to grow at an even faster rate. To distribute these scarce and precious resources equitably, donor heart placement is based on clinical need with priority given to those who are more critically ill. As a result, donors are matched with recipient candidates over increasingly farther distances, which may subject these organs to longer ischemic times. One of the mainstays of successful heart transplantation is successful organ preservation while the donor organ is ex vivo from the time of donor procurement to recipient implantation. In order to adapt to a new era of heart transplantation where organs are shared across wider ranges, preservation strategies must evolve to accommodate longer ischemia times while mitigating the harmful sequalae of ischemia-reperfusion injury. Additionally, in order to address the ever-growing supply demand mismatch of donor organs, evolving perfusion technologies may allow for further evaluation of donor grafts outside of conventional acceptance practices, thus enlarging the effective donor pool. Herein this review, we discuss the history of organ preservation, current strategies and modalities employed in current practice, along with developing technologies in preclinical stages. Lastly, we introduce the concept of donation after circulatory death (DCD), which has been until recently a largely unexplored avenue of heart donation that relies much on current preservation techniques. Full article

A complete and prompt cardiac arrest using a cold cardioplegic solution is routinely used in heart transplantation to protect the graft function. However, warm ischemic time is still inevitable during the procedure to isolate donor hearts in the clinical setting. Our knowledge of the mechanism changes prevented by cold storage, and how warm ischemia damages donor hearts, is extremely poor. The potential consequences of this inevitable warm ischemic time to grafts, and the underlying potential protective mechanism of prompt graft cooling, have been studied in order to explore an advanced graft protection strategy. To this end, a surgical procedure, including 10–15 min warm ischemic time during procurement, was performed in mouse models to mimic the clinical situation (Group I), and compared to a group of mice that had the procurement performed with prompt cooling procedures (Group II). The myocardial morphologic changes (including ultrastructure) were then assessed by electron and optical microscopy after 6 h of cold preservation. Furthermore, syngeneic heart transplantation was performed after 6 h of cold preservation to measure the graft heart function. An electron microscopy showed extensive damage, including hypercontracted myofibers with contraction bands, and damaged mitochondria that released mitochondrial contents in Group I mice, while similar patterns of damage were not observed in the mice from Group II. The results from both the electron microscopy and immunoblotting verified that cardiac mitophagy (protective mitochondrial autophagy) was present in the mice from Group II, but was absent in the mice from Group I. Moreover, the mice from Group II demonstrated faster rebeating times and higher beating scores, as compared to the mice from Group I. The pressure catheter system results indicated that the graft heart function was significantly more improved in the mice from Group II than in those from Group I, as demonstrated by the left ventricle systolic pressure (31.96 ± 6.54 vs. 26.12 ± 8.87 mmHg), the +dp/dt (815.6 ± 215.4 vs. 693.9 ± 153.8 mmHg/s), and the -dp/dt: (492.4 ± 92.98 vs. 418.5 ± 118.9 mmHg/s). In conclusion, the warm ischemic time during the procedure impaired the graft function and destroyed the activation of mitophagy. Thus, appropriate mitophagy activation has emerged as a promising therapeutic target that may be essential for graft protection and functional improvement during heart transplantation. Full article

In recent years, the opioid epidemic and new hepatitis C virus (HCV) treatments have changed the landscape of organ procurement and allocation. We studied national trends in solid organ transplantation (2000–2016), focusing on graft utilization from HCV seropositive deceased donors in the pre-2014 (2000–2013) versus current (2014–2016) eras with a retrospective analysis of the United Network for Organ Sharing database. During the study period, HCV seropositive donors increased from 181 to 661 donors/year. The rate of HCV seropositive donor transplants doubled from 2014 to 2016. Heart and lung transplantation data were too few to analyze. A higher number of HCV seropositive livers were transplanted into HCV seropositive recipients during the current era: 374 versus 124 liver transplants/year. Utilization rates for liver transplantation reached parity between HCV seropositive and non-HCV donors. While the number of HCV seropositive kidneys transplanted to HCV seropositive recipients increased from 165.4 to 334.7 kidneys/year from the pre-2014 era to the current era, utilization rates for kidneys remained lower in HCV seropositive than in non-HCV donors. In conclusion, relative underutilization of kidneys from HCV seropositive versus non-HCV donors has persisted, in contrast to trends in liver transplantation. Full article

Heart transplantation (HTx) is the ultimate treatment for end-stage heart failure. The number of patients on waiting lists for heart transplants, however, is much higher than the number of available organs. The shortage of donor hearts is a serious concern since the population affected by heart failure is constantly increasing. Furthermore, the long-term success of HTx poses some challenges despite the improvement in the management of the short-term complications and in the methods to limit graft rejection. Myocardial injury occurs during transplantation. Injury initiated in the donor as result of brain or cardiac death is exacerbated by organ procurement and storage, and is ultimately amplified by reperfusion injury at the time of transplantation. The innate immune system is a mechanism of first-line defense against pathogens and cell injury. Innate immunity is activated during myocardial injury and produces deleterious effects on the heart structure and function. Here, we briefly discuss the role of the innate immunity in the initiation of myocardial injury, with particular focus on the Toll-like receptors and inflammasome, and how to potentially expand the donor population by targeting the innate immune response. Full article