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

Evaluation of target temperature on effectiveness of myocardial preservation during hypothermic machine perfusion

Background

Ex-situ heart perfusion (ESHP) has been proposed as an optimal method for preserving donated hearts prior to transplantation. Hypothermic oxygenated perfusion (HOP) is a simple method from a device design perspective, with enhanced safety compared to normothermic perfusion in the event of device failure. However, the optimal temperature for cardiac HOP has yet to be determined. We evaluated the effectiveness of 12-hour HOP using University of Wisconsin Machine Perfusion Solution (UWMPS) in different temperatures compared to static cold storage (SCS) for 6 hours followed by simulated transplantation. Additionally, we sought to determine the impact of oxygen supplementation in hypothermic ESHP in the heart function preservation.

Methods

Hearts were procured from Yorkshire pigs (n = 35) randomized into 3 preservation therapies: 6 hours-SCS; 12 hours-HOP and 12 hours hypothermic non-oxygenated perfusion (HNOP-without oxygen supplementation). For either HOP or HNOP groups, 3 temperatures were tested (5°C; 10°C; 15°C). After the preservation period, hearts had their function assessed in a normothermic perfusion machine capable of working mode, simulating transplantation.

Results

All perfusion parameters were stable throughout (mean ± SD): aortic flow 65 ± 5.57 ml/min, aortic pressure: 11.51 ± 3.17 mm Hg. All HOP hearts presented a better cardiac index than SCS (p < 0.05). The HNOP hearts presented similar cardiac function results compared to SCS.

Conclusions

HOP for 12 hours had better heart function preservation than SCS for 6 hours. Even HNOP had similar results compared to SCS. Greater edema formation in ESHP hearts did not affect heart function. Hypothermic ESHP safely enhances function preservation compared to SCS.

Innovative approaches to organ preservation in heart transplantation: A comprehensive review by the French Society of Thoracic and Cardiovascular Surgery

Improved approaches for organ preservation have been recently applied in heart transplantation to prevent the risk of primary graft dysfunction. To review heart-graft preservation systems and to identify criteria for using innovative devices in each specific situation. A working group of the French Society of Thoracic and Cardiovascular Surgery performed a literature review focusing on organ preservation and post-transplant outcomes. Static cold storage is the most widely used method but involves cold ischaemia and is therefore limited for prolonged preservation. Optimizing this method by ensuring uniform and stable cooling (SherpaPak™) seems to be associated with favourable results, even with expanded-criteria grafts. Continuous normothermic organ perfusion (Organ Care System) shortens the cold ischaemia time, thus maintaining heart-graft viability despite long transportation times or long waits to achieve complex recipient-heart explantation. Moreover, this method can rehabilitate Maastricht III heart grafts. Continuous hypothermic oxygenated perfusion (XVivo™, not yet approved by regulatory authorities) has recently been associated with favourable outcomes, even in case of extended out-of-body preservation>8hours. The new devices for heart preservation can be expected to allow successful transplantation despite long transport times, lengthy explantation procedures and the use of grafts from expanded-criteria donors, including donors after controlled circulatory arrest. Further studies are needed to assess patient and graft outcomes, determine the optimal device for each situation and evaluate the cost-benefit ratio.

Current approaches to optimize the donor heart for transplantation

Heart transplantation remains a critical therapy for patients with end-stage heart failure, offering incremental survival and improved quality of life. One of the key components behind the success of heart transplantation is the condition and preservation of the donor's heart. In this review, we provide a comprehensive overview of ischemic reperfusion injury, risk factors associated with primary graft dysfunction, current use of various preservation solutions for organ procurement, and recent advancements in donor heart procurement technologies. This state-of-the-art review will explore factors associated with bringing the "ideal" donor heart to the operating room in the contemporary era.

Evaluating the mechanism of action behind controlled hypothermic preservation of donor hearts: A randomized pilot study

BACKGROUND

Controlled hypothermic preservation of donor hearts is associated with decreased post-transplant primary graft dysfunction compared to conventional cold storage. However, mechanisms underlying this benefit in human subjects are unclear.

METHODS

We randomized 20 heart transplant recipients at a single institution to receive donor hearts preserved with either controlled hypothermic preservation or standard cold storage. Right ventricular biopsies were obtained at donor heart recovery, immediately before implantation, and 7 days after transplantation. Protein expression profiles at each time point were evaluated using mass spectrometry, Protein Interaction Network Extractor analysis, and Ingenuity Pathway Analysis.

RESULTS

Immediately before implantation, controlled hypothermic preservation was associated with increased protein expression related to fatty acid metabolism, mitochondrial intermembrane space, and contractile fiber machinery. Pathway analysis indicated increased cell viability, autophagy, and upregulation of AMP-activated protein kinase pathway with controlled hypothermic preservation. By post-transplant day 7, the protein expression profiles of the 2 groups were similar. However, controlled hypothermic preservation was associated with increased expression in the peroxisome proliferator-activated receptor signaling pathway and fatty acid oxidation.

CONCLUSIONS

Controlled hypothermic preservation of donor hearts shows beneficial time-dependent variability in protein expression that may confer improved organ quality at the time of transplantation.

Metabolic and transcriptomic insights into temperature controlled hypothermic preservation of human donor hearts

BACKGROUND

Heart transplantation (HT) is the gold standard for end-stage heart disease. Donor heart preservation is an important factor that influences post-transplant success. Recently, temperature-controlled storage has demonstrated reduced primary graft dysfunction compared to standard cold storage though mechanisms are poorly understood. We hypothesized that alterations in gene expression and metabolomics offer insight into improved outcomes observed with temperature-controlled storage.

METHODS

We conducted a comprehensive study to investigate the metabolic and transcriptomic responses of donor hearts preserved for 6 hours using a temperature-controlled hypothermic preservation (TCHP) system compared to conventional static cold storage (SCS). Metabolic assessments were carried out using high-resolution 1H and 31P nuclear magnetic resonance (NMR), and liquid chromatography/mass spectrometry (LC-MS) analysis on tissues obtained from various cardiac regions. Lactate, alanine, adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), nicotinamide adenine dinucleotide (NAD), reduced nicotinamide adenine dinucleotide (NADH), phosphocreatine, and inorganic phosphate were measured, and metabolite ratios were calculated. Transcriptomic profiling was conducted using high throughput RNA sequencing followed by bioinformatic analysis to explore gene expression changes associated with different preservation methods.

RESULTS

Metabolic analyses revealed largely similar profiles between hearts preserved with TCHP and SCS. Energy metabolite ratios were comparable between preservation methods. Transcriptomic analysis unveiled a high correlation between preservation methods but also showed differential gene expression in energy metabolism and inflammation/immune-related pathways.

CONCLUSIONS

Our study demonstrates that TCHP maintains similar high-energy phosphate reserves to SCS but leads to alterations in gene expression of several metabolic and immunomodulatory pathways. These findings may offer important insight into reduced primary graft dysfunction observed in TCHP- hearts.

Regional differences in primary graft dysfunction: A report from the international consortium on PGD

BACKGROUND

The impact of regional differences on primary graft dysfunction (PGD) after heart transplantation (HT) has not been assessed. This study aims to compare differences in the incidence, risk factors, and outcomes of severe PGD in the US, Canada, and Europe.

METHODS

This retrospective, observational study included consecutive adult HT recipients from 14 centers between 2010-2022. The primary outcome was severe PGD as defined by ISHLT criteria. Multivariable logistic regression analyses were conducted. Survival data were analyzed using a proportional hazards Cox model.

RESULTS

4101 HT recipients were included in the analysis (2077 US, 730 Canada, 1294 Europe). Significant differences were observed in recipient cardiovascular risk factors, pre-HT mechanical circulatory support (MCS), ischemic time, and donor age. Severe PGD occurred in 8.6%, 9.0%, and 9.6% of HTs in the US, Canada, and Europe. There was an increasing trend in severe PGD incidence in the US and Canada over time. Risk factors for severe PGD were similar across regions and included pre-HT dialysis, durable LVAD or pre-HT MCS, and ischemic time. VA-ECMO was the preferred MCS strategy for PGD management in all three regions. Thirty-day (8.9%, 29.8%, 43.9%) and 1-year (26.3%, 50.8%, 48.5%) mortality after severe PGD in the US was significantly lower than in Canada and Europe.

CONCLUSIONS

The incidence of severe PGD is similar across the US, Canada, and Europe, but with a lower mortality after severe PGD in the US. Analyzing regional differences in PGD can aid in development of best practices for survival after this devastating event.

Experimental Study on Myocardial Protective Effect of Xuebijing Injection on Extracorporeal Membrane Oxygenation Perfused Isolated Heart: Based on Autophagy and NLRP3 Inflammatory Pathway

BACKGROUND

The purpose of this study was to investigate the myocardial protective effect of Xuebijing (XBJ) injection in isolated donor heart preservation based on autophagy and NLRP3 inflammatory pathway, and to provide clues for improving the quality of donor heart preservation in the clinic.

METHODS

Fourteen Guangxi Bama miniature pigs were randomly divided into two groups to establish the isolated heart perfusion model of extracorporeal membrane oxygenation (ECMO): (1) normal saline group (NS group): 50 mL normal saline was added to the perfusion solution; and (2) Xuebijing injection group (XBJ group): 10 mL of XBJ was added to the perfusate. Both groups were continuously pumped with 5 mL/h for 8 hours. Hemodynamic changes, inflammatory reaction, and myocardial enzyme levels were observed at five different time points. Western blot and real-time quantitative polymerase chain reaction (RT-qPCR) were used to detect the expression of autophagy markers and the NLRP3 signaling pathway related factors mRNA in myocardial tissue. Hematoxylin and eosin (H&E) staining and transmission electron microscopy were used to observe the pathomorphology and ultrastructure of the myocardium.

RESULTS

There was no significant difference in perfusion pressure, heart rate, perfusion flow, and PH value between the two groups. The degree of myocardial tissue injury in the XBJ group was lighter, and the levels of myocardial enzymes, serum inflammatory factors were lower. The mRNA expression levels of beclin-1 and LC3 in the XBJ group were higher than those in the saline group, and the mRNA expression levels of NLRP3, Caspase-1, and ASC were lower.

CONCLUSIONS

Xuebijing injection can effectively improve the level of autophagy, reduce the activation and release of NLRP3 inflammasome, and slow down the inflammatory response, which has a certain myocardial protection effect.

Donor Selection for Heart Transplantation in 2025

The number of candidates on the waiting list for heart transplantation (HT) continues to far outweigh the number of available organs, and the donor heart nonuse rate in the United States remains significantly higher than that of other regions such as Europe. Although predicting outcomes in HT remains challenging, our overall understanding of the factors that play a role in post-HT outcomes continues to grow. We observe that many donor risk factors that are deemed "high-risk" do not necessarily always adversely affect post-HT outcomes, but are in fact nuanced and interact with other donor and recipient risk factors. The field of HT continues to evolve, with ongoing development of technologies for organ preservation during transport, expansion of the practice of donation after circulatory death, and proposed changes to organ allocation policy. As such, the field must continue to refine its processes for donor selection and risk prediction in HT.

DCDD heart transplantation with thoraco-abdominal normothermic regional perfusion and static cold storage: The experience in Spain

Heart transplantation from donors after the circulatory determination of death is expanding worldwide. Thoraco-abdominal normothermic regional perfusion (TA-NRP) allows the validation and recovery of the donation after the circulatory determination of death (DCDD) heart, but there is limited evidence on the results of heart transplants performed with this approach. This multicenter, nationwide, prospective study describes the short-term outcomes of adult patients receiving a DCDD heart transplant obtained via TA-NRP followed by static cold storage in Spain. Recipients of hearts from donors after the neurologic determination of death were used as controls. The primary outcome was a composite of 1-year all-cause death or severe primary graft failure. During 2020-2023, 98 adult DCDD and 347 donations after the neurologic determination of death (DNDD) heart transplants were performed across 11 centers. The primary outcome was met by 21 (21.4%) and 77 (22.2%) patients, respectively (P = .87). Thirty-day and 1-year survival were 94.9% and 88.8% in the DCDD vs 93.7% and 87.3% in the DNDD group (P = .70), respectively. Severe primary graft failure was observed in 13 (13.3%) vs 52 (15.0%) patients (P = .67). By inverse probability weighting, the DCDD heart was not associated with the primary outcome (hazard ratio, 0.97; 95% confidence interval, 0.58-1.62; P = .91). In conclusion, adult DCDD heart transplantation based on TA-NRP and static cold storage provides similar short-term outcomes than DNDD heart transplants.

Clinical Outcomes of Machine Perfusion and Temperature Control Systems in Heart Transplantation: Where We Stand

Heart transplantation remains the preferred treatment for carefully selected patients with end-stage heart failure refractory to medical therapy. Advances in donor management, organ preservation, donor and recipient selection, immunosuppressive strategies, and mechanical circulatory support have significantly improved the safety and efficacy of heart transplantation. However, the persistent shortage of donor hearts and their limited preservation period continues to restrict access to this lifesaving procedure. The advent of innovative machine perfusion and temperature control systems for heart allograft preservation offers a promising avenue to address these challenges. These technologies aim to extend preservation times and enable the use of extended-criteria donors, thereby expanding the donor pool. In this review, we examine the outcomes from clinical trials, registry data, and single-center studies, utilizing the TransMedics Organ Care System Heart, Paragonix SherpaPak Cardiac Transport System, and XVIVO Heart Preservation System. As the field of heart transplantation evolves to accommodate longer ischemia times, expand organ sharing, and utilize donors previously considered marginal, the integration of these advanced technologies will be essential for optimizing post-transplant outcomes.

Donor Heart Preservation for Heart Transplantation: Single-Center Experience with Three Different Techniques

Objectives: In addition to traditional ice-cold storage (ICS), other techniques are emerging in the field of donor heart preservation for heart transplantation (HTx). However, in many centers, it could be difficult to justify their use, due to the higher costs and the greater technical complexity compared to ICS. This study aims to analyze the results obtained for HTx at our center employing ICS, controlled hypothermia with Paragonix SherpaPak (PSP), and ex vivo normothermic perfusion with Organ Care System (OCS) as donor graft preservation strategies. Methods: All HTx performed at the University Hospital of Udine, between January 2020 and August 2024, was analyzed and patient outcomes and complications after HTx were assessed. Endomyocardial biopsies were performed in donor hearts immediately after retrieval (T0), before implantation (T1), and at reperfusion (T2) to evaluate signs of myocardial damage. Results: Overall, 100 patients were transplanted with a donor heart preserved with ICS (n = 30), PSP (n = 36), or OCS (n = 34). Compared to ICS, PSP and OCS recipients showed a higher median IMPACT score (5 vs. 8 vs. 7, respectively, p = 0.05) and tended to have a higher rate of bridging to HTx with a long-term ventricular assist device (7% vs. 17% vs. 29%, p = 0.06). OCS was more commonly used in cases of expected ischemic time >4 h compared to ICS and PSP (p < 0.01). Histologically, severe degrees of cellular damage were higher in those hearts preserved with ICS. The 30-day mortality was 3% vs. 6% vs. 9% in ICS, PSP, and OCS groups, respectively (p = 0.65). Moderate-to-severe primary graft dysfunction was 37% vs. 11% vs. 17% (p = 0.03) in the three groups. Conclusions: PSP and OCS seem to be valid alternatives to traditional ICS, and their use could be strongly considered, particularly in the most complex and critical settings, until further data are available on more patient experiences.

Ice-cold storage or controlled hypothermia to preserve marginal grafts in high-risk heart transplantation

BACKGROUND

To evaluate the effectiveness of the Paragonix SherpaPak cardiac transport system (PSP) compared to the standard ice-cold storage (ICS) in extended-criteria donor grafts implanted in high-risk recipients.

METHODS

Data of all HTx at the University Centers of Udine and Bologna, between January 2020 and December 2023, employing extended-criteria donors in high-risk HTx conditions were retrospectively analyzed. Patient outcomes and complications after HTx were assessed. Endomyocardial biopsies were performed in donor hearts immediately after retrieval (T0), before implantation (T1) and at reperfusion (T2) to evaluate signs of myocardial damage.

RESULTS

Overall, 90 patients who had heart transplantation (HTx) with a donor graft preserved with either ICS (n = 60) or PSP (n = 30) were included in the study. The 30-day mortality was 3% in both groups (p = 0.99), and 1-year survival 90% and 88% (p = 0.89) for recipients transplanted with PSP and ICS preserved grafts. Rates of moderate-to-severe graft dysfunction and bradi-arrhythmias for PSP and ICS groups were 7% versus 20% (p = 0.08), and 3% versus 15% (p = 0.09). Histologically, severe degrees of cellular and endothelial damage were absent in all PSP grafts while severe degree of contraction bands were higher in ICS hearts at T2.

CONCLUSIONS

In high-risk donor-recipient matching, donor heart preservation with PSP seems to show a tendency toward better graft protection.

SherpaPak Cardiac Transport System: Experience in Pediatric Heart Transplantation

INTRODUCTION

The present study aimed to assess the clinical outcomes of pediatric heart transplant patients whose donor hearts were preserved with the SherpaPakCardiac Transport System.

METHODS

All pediatric patients undergoing heart transplantation at our center between January 2020 and June 2024 were included and described. Vasoactive inotropic score (VIS) was calculated. The cohort was divided into two groups by recipient diagnoses (cardiomyopathy vs. congenital heart disease [CHD]). They were compared based on demographics, operative details, and postoperative outcomes. The χ2 and Fisher exact tests were used for categorical variables and the Mann-Whitney U test or t-test for continuous variables.

RESULTS

A total of 18 patients were included. The median recipient age was 11.9 years (IQR: 2.5, 13.9). Half had cardiomyopathy, median total ischemic time was 236 min (IQR: 211.5, 283.5). Upon comparing the two groups, there were no significant differences observed in VIS or primary graft dysfunction (PGD) even though the median circulatory arrest time and bypass times were significantly longer in the CHD group (p < 0.05). Three patients experienced early rejection (all with CHD), but there was no mortality.

CONCLUSIONS

The SherpaPak Cardiac Transport System provides safe outcomes for pediatric heart transplant patients, including those with complex CHD. Further multi-institutional and registry studies are needed to evaluate this method for pediatric heart transplantation.

Primary Graft Dysfunction after Heart Transplantation: Current Evidence and Implications for Clinical Practice

PURPOSE OF REVIEW

This review summarizes the current literature on primary graft dysfunction highlighting the current definition, reviewing epidemiology, and describing donor, recipient, and perioperative risk factors in the contemporary era.

RECENT FINDINGS

PGD, in its most severe form, complicates 8% of heart transplants and portends a 1-year mortality of close to 40%. PGD is multifactorial and heterogeneous with contributions from donor and recipient risk as well as organ recovery and preservation modalities. Biomarkers may enhance risk stratification and lend insight into the underlying mechanism of PGD. Temperature-controlled storage and hypothermic oxygenation perfusion systems, in particular, may have significant potential to mitigate PGD risk. PGD is a devastating early complication of heart transplantation that is both complex and multifactorial. Despite its incidence and impact the underlying biology of PGD remains poorly understood. Future studies mechanistic studies are needed to address the underlying pathophysiology of PGD to develop targeted prophylactic and/or therapeutic interventions.

The Rapidly Evolving Landscape of DCD Heart Transplantation

PURPOSE OF REVIEW

To summarise current international clinical outcomes from donation after circulatory death heart transplantation (DCD-HT); discuss procurement strategies, their impact on outcomes and overall organ procurement; and identify novel approaches and future areas for research in DCD-HT.

RECENT FINDINGS

Globally, DCD-HT survival outcomes (regardless of procurement strategy) are comparable to heart transplantation from brain dead donors (BDD). Experience with normothermic machine perfusion sees improvement in rates of primary graft dysfunction. Techniques have evolved to reduce cold ischaemic exposure to directly procured DCD hearts, though controlled periods of cold ischaemia can likely be tolerated. There is interest in hypothermic machine perfusion (HMP) for directly procured DCD hearts, with promising early results. Survival outcomes are firmly established to be equivalent between BDD and DCD-HT. Procurement strategy (direct procurement vs. regional perfusion) remains a source of debate. Methods to improve allograft warm ischaemic tolerance are of interest and will be key to the uptake of HMP for directly procured DCD hearts.

European Society of Organ Transplantation (ESOT) Consensus Statement on Machine Perfusion in Cardiothoracic Transplant

The machine perfusion (MP) of transplantable grafts has emerged as an upcoming field in Cardiothoracic (CT) transplantation during the last decade. This technology carries the potential to assess, preserve, and even recondition thoracic grafts before transplantation, so it is a possible game-changer in the field. This technology field has reached a critical turning point, with a growing number of publications coming predominantly from a few leading institutions, but still need solid scientific evidence. Due to the increasing need to expand the donor pool, especially in Europe, where the donor age is steeply increased, a consensus has been established to address the growing need and knowledge of machine perfusion in cardiothoracic transplantation, targeting the unmet scientific need in this growing field but also, priorities for development, and regional differences in utilization rates and organizational issues. To address MP in CT, the European Society of Organ Transplantation (ESOT) convened a dedicated Working group comprised of experts in CT to review literature about MP to develop guidelines that were subsequently discussed and voted on during the Consensus Conference that took place in person in Prague during the TLJ 3.0 in November 2022. The findings and recommendations of the Cardiothoracic Working Group on MP are presented in this article.

Direct procurement with machine perfusion and normothermic regional perfusion in donation after circulatory death heart transplantation

BACKGROUND

Donation after circulatory death (DCD) heart transplants have increased in the United States with direct procurement with machine perfusion (DPP) and thoracoabdominal normothermic regional perfusion (TA-NRP) techniques. There remains a paucity of data examining DPP and TA-NRP outcomes. The purpose of this study was to investigate the impact of the DCD technique on post-transplant outcomes compared to donation after brain death (DBD) donors.

METHODS

Adult patients undergoing heart transplantation between December 1, 2019, and June 30, 2023, were identified in the United Network for Organ Sharing registry. DPP and TA-NRP groups were identified using time of death to an aortic cross-clamp time of 30 minutes. Categorical variables were compared using the χ2 or Fisher exact test, and continuous variables were compared using the Mann-Whitney U test. Propensity score matching was performed using a 1:3 match. One-year survival was analyzed using the log-rank test and a Cox proportional hazard regression model.

RESULTS

During the study period, there were 7338 DBD and 419 DCD heart transplants. At 1 year post-transplant, there was no difference in survival between unmatched (P = .13) and matched (P = .36) DBD and DCD heart recipients. There was an increase in acute rejection and rejection requiring treatment in DCD recipients compared to DBD recipients in the matched cohort. A total of 134 TA-NRP transplants and 242 DPP transplants were performed. One-year survival and post-transplant outcomes were similar in the DPP and TA-NRP groups. TA-NRP functional warm ischemia time (fWIT) was increased significantly during the study period.

CONCLUSIONS

In this matched cohort, DCD heart recipients experienced increased acute rejection, both treated and nontreated, compared to DBD heart recipients. Despite differences in the techniques and likely in fWIT, acute rejection, survival, and other secondary outcomes are similar with DPP and TA-NRP.

An Unexpected Partnership: Alexis Carrel, Charles Lindbergh, and Normothermic Machine Perfusion

Organ transplantation is a triumph of modern medicine which represents a culmination of science and imagination, saving thousands of lives a year. However, transplantation is severely limited by suitable donor allografts. To expand the donor pool and make transplantation achievable for all, normothermic machine perfusion (NMP) is being employed more frequently. Normothermic machine perfusion involves the utilization of a device to approximate the physiology of the human body, preserve organs outside of the donor, and provide a dynamic assessment platform to determine organ suitability for transplantation. As NMP technology advances, it will soon be possible to genetically modify and actively repair these organs. Although its application to the field of transplantation is relatively new, the concept, foundation, and development of NMP can be traced back to the pioneering work of the surgeon-scientist, Alexis Carrel and the famous aviator, Charles Lindbergh in the 1930s. Their collaboration resulted in the Carrel-Lindbergh Perfusion device, an early perfusion device that was able to keep organs alive ex vivo for weeks and is most appropriately viewed as a precursor to modern machine perfusion technologies. As NMP technology becomes more advanced and refined, it is important to acknowledge the historical context in which these technologies emerged.

Out of the ice age: Preservation of cardiac allografts with a reusable 10 °C cooler

Objective

Static cold storage with ice has been the mainstay of cardiac donor preservation. Early preclinical data suggest that allograft preservation at 10 °C may be beneficial. We tested this hypothesis by using a static 10 °C storage device to preserve and transport cardiac allografts.

Methods

In total, 52 allografts were recovered between July 2023 and March 2024 and transported using a 10 °C storage cooler. Results were compared to a 3:1 propensity match of allografts transported on ice. Patients were excluded for the following reasons: dual viscera transplant, previous heart transplant, complex congenital heart disease, or allograft injury during procurement.

Results

Among the 10 °C cooler cohort, median total ischemic time was 222 minutes at 10 °C versus 193 minutes on ice (P < .0001). Intraoperative change in lactate was statistically lower at 10 °C (3.6 vs 5.1 mmol/L, P = .0016). Cardiac index score was greater in 10 °C cooler hearts at 24 (3.2 vs 3.0, P = .016) and 72 hours (3.3 vs 2.9, P = .037), despite similar vasoactive inotrope scores. There was no difference in severe primary graft dysfunction (1.9 vs 2.6%, P > .99). 10 °C hearts demonstrated less change in lactate but no difference in vasoactive inotrope scores or cardiac index. In hearts with extended ischemic time, delta lactate was lower in 10 °C cooler hearts. There was no statistical difference in outcomes for donor hearts >40 years old.

Conclusions

This is an early experience of static preservation in a 10 °C cooler. Postoperative allograft function was excellent, and lactate profiles lower in those allografts with extended ischemic times. Static cold storage targeting 10 °C may offer an inexpensive method for extended heart preservation. Further investigation is needed to assess long-term outcomes of 10 °C storage.

Procurement Trends, Indications, and Outcomes of Heart-Lung Transplantation in the Contemporary Era

BACKGROUND

Evolving trends in organ procurement and technological innovation prompted an investigation into recent trends, indications, and outcomes following combined heart-lung transplantation (HLTx).

METHODS

The United Network for Organ Sharing database was queried for all adult (≥18 years) HLTx performed between July 1, 2013 and June 30, 2023. Patients with previous transplants were excluded. The primary endpoint was the effect of donor, recipient, and transplantation characteristics on 1- and 5-year survival. Secondary analyses included a comparison of HLTx at high- and low-volume centers, an assessment of HLTx following donation after circulatory death (DCD), and an evaluation of HLTx volume over time. Cox proportional-hazards models were used to assess factors associated with mortality. Temporal trends were evaluated with linear regression.

RESULTS

After exclusions, 319 patients were analyzed, of whom 5 (1.6%) were DCD. HLTx volume increased from 2013 to 2023 (p < 0.001). One- and 5-year survival following HLTx was 84.0% and 59.5%, respectively. One-year survival was higher for patients undergoing HLTx at a high-volume center (88.3% vs. 77.9%; p = 0.012). After risk adjustment, extracorporeal membrane oxygenation support 72 h posttransplant and predischarge dialysis were associated with increased 1-year mortality (HR = 3.19, 95% CI = 1.86-5.49 and HR = 3.47, 95% CI = 2.17-5.54, respectively) and 5-year mortality (HR = 2.901, 95% CI = 1.679-5.011 and HR = 3.327, 95% CI = 2.085-5.311, respectively), but HLTx at a high-volume center was not associated with either.

CONCLUSIONS

HLTx volume has resurged, with DCD HLTx emerging as a viable procurement strategy. Factors associated with 1- and 5-year survival may be used to guide postoperative management following HLTx.