Primary graft failure after heart transplantation

Comparative Analysis of Ischemia-Reperfusion Injury in Heart Transplantation: A Single-Center Study Evaluating Conventional Ice-Cold Storage versus the Paragonix SherpaPak Cardiac Transport System

BACKGROUND

Since the 2018 allocation system change in heart transplantation (HT), ischemic times have increased, which may be associated with peri-operative and post-operative complications. This study aimed to compare ischemia reperfusion injury (IRI) in hearts preserved using ice-cold storage (ICS) and the Paragonix SherpaPak TM Cardiac Transport System (CTS).

METHODS

From January 2021 to June 2022, consecutive endomyocardial biopsies from 90 HT recipients were analyzed by a cardiac pathologist in a single-blinded manner: 33 ICS and 57 CTS. Endomyocardial biopsies were performed at three-time intervals post-HT, and the severity of IRI manifesting histologically as coagulative myocyte necrosis (CMN) was evaluated, along with graft rejection and graft function.

RESULTS

The incidence of IRI at weeks 1, 4, and 8 post-HT were similar between the ICS and CTS groups. There was a 59.3% statistically significant reduction in CMN from week 1 to 4 with CTS, but not with ICS. By week 8, there were significant reductions in CMN in both groups. Only 1 out of 33 (3%) patients in the ICS group had an ischemic time >240 mins, compared to 10 out of 52 (19%) patients in the CTS group. During the follow-up period of 8 weeks to 12 months, there were no significant differences in rejection rates, formation of de novo donor-specific antibodies and overall survival between the groups.

CONCLUSION

The CTS preservation system had similar rates of IRI and clinical outcomes compared to ICS despite longer overall ischemic times. There is significantly more recovery of IRI in the early post operative period with CTS. This study supports CTS as a viable option for preservation from remote locations, expanding the donor pool.

Donor plasma VEGF-A as a biomarker for myocardial injury and primary graft dysfunction after heart transplantation

BACKGROUND

Vascular endothelial growth factor (VEGF)-A is an angiogenic and proinflammatory cytokine with profound effects on microvascular permeability and vasodilation. Several processes may induce VEGF-A expression in brain-dead organ donors. However, it remains unclear whether donor VEGF-A is linked to adverse outcomes after heart transplantation.

METHODS

We examined plasma VEGF-A levels from 83 heart transplant donors as well as the clinical data of these donors and their respective recipients operated between 2010 and 2016. The donor plasma was analyzed using Luminex-based Multiplex and confirmed with a single-target ELISA. Based on donor VEGF-A plasma levels, the recipients were divided into 3 equal-sized groups (low VEGF <500 ng/liter, n = 28; moderate VEGF 500-3000 ng/liter, n = 28; and high VEGF >3000 ng/liter, n = 27). Biochemical and clinical parameters of myocardial injury as well as heart transplant and kidney function were followed-up for one year, while rejection episodes, development of cardiac allograft vasculopathy, and mortality were monitored for 5 years.

RESULTS

Baseline parameters were comparable between the donor groups, except for age, where median ages of 40, 45, and 50 were observed for low, moderate, and high donor plasma VEGF levels groups, respectively, and therefore donor age was included as a confounding factor. High donor plasma VEGF-A levels were associated with pronounced myocardial injury (TnT and TnI), a higher inotrope score, and a higher incidence of primary graft dysfunction in the recipient after heart transplantation. Furthermore, recipients with allografts from donors with high plasma VEGF-A levels had a longer length of stay in the intensive care unit and the hospital, and an increased likelihood for prolonged renal replacement therapy.

CONCLUSIONS

Our findings suggest that elevated donor plasma VEGF-A levels were associated with adverse outcomes in heart transplant recipients, particularly in terms of myocardial injury, primary graft dysfunction, and long-term renal complications. Donor VEGF-A may serve as a potential biomarker for predicting these adverse outcomes and identifying extended donor criteria.

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.

Application of nanomaterials in heart transplantation: a narrative review

Background and Objective

Heart transplantation (HT) is a therapeutic option for end-stage heart disease. Still, it faces many challenges, especially the shortage of donor sources and the poor durability of grafts, which are the two critical issues. In this review, we generalize the application of existing nanomedicine technologies in donor management as well as prevention and diagnosis of post-transplantation complications, also including the current preclinical studies of nanomaterials in cardiac tissue engineering and gene-editing xeno-donor grafts. Finally, we discuss the remaining problems and future directions of nanomaterials in the field of HT.

Methods

A narrative review using current search of the most recent literature on the topic. The terms "nanomaterials", "nano medicine'', "Heart transplantation (HT)", "Nano-drug delivery system (NDDS)" or their combination were searched in PubMed and Google Scholar. The specified timeframe began from 1990, and we prioritized publications mainly from the last 10 years.

Key Content and Findings

Nano-systems integrating therapeutic and diagnostic functions have been applied to cardiovascular diseases (CVDs) with their unique advantages in multiple fields such as drug delivery, tissue engineering, gene editing, imaging, biomarker editing, and many other aspects. In terms of transplantation, the preservation, transportation, and pretreatment of donor hearts machine perfusion (MP) provide the possibility for nano-systems with unique features, and therapeutic and diagnostic functions to be directly and passively targeted in order to improve the functional status of the transplanted organs or to increase the ability to tolerate the graft of patients. The development of nano-imaging, nanosensor, and nano biomarker technologies are also being applied to monitor the status of transplant recipients for early prevention and treatment of post-transplantation-related complications. Nanomaterials combined with cardiac tissue engineering and gene editing technologies could also expand graft sources and alleviate donor shortages.

Conclusions

Although the overall research on nanomaterial applications in the field of HT is in its infancy, its role in improving the prognosis of transplant recipients and breaking the current dilemma of HT is clear. However, before nanotechnologies can be translated into clinical applications in the future, they must be aimed at ensuring the drug delivery system's safety and pose a challenge in the direction of the ability to intervene with multiple drugs in combination.

Association of cardiac preservation solution with short-term outcomes after heart transplantation

AIMS

There is wide variability in the practice of cardiac preservation for heart transplantation. Prior reports suggest that the type of solution may be linked with a reduced incidence of posttransplantation complications.

METHODS

Adult (≥18 years old) heart recipients who underwent transplantation between 2015 and 2021 in the United States were examined. Recipients were stratified by solution utilized for their grafts at the time of recovery: University of Wisconsin, histidine-tryptophan-ketoglutarate (HTK), or Celsior solution. The primary endpoint was a composite of 30-day mortality, primary graft dysfunction, or re-transplantation. Risk adjustment was performed for the recipient, donor, and procedural characteristics using regression modeling.

RESULTS

Among 16 884 recipients, the group distribution was University of Wisconsin solution 53%, HTK 22%, Celsior solution 15%, and other 10%. The observed incidence of the composite endpoint (University of Wisconsin solution = 3.6%, HTK = 4.0%, Celsior solution = 3.7%, P = 0.301) and 1-year survival (University of Wisconsin solution = 91.7%, HTK = 91.3%, Celsior solution = 91.7%, log-rank P = 0.777) were similar between groups. After adjustment, HTK was associated with a higher risk of the composite endpoint [odds ratio (OR) 1.249, 95% confidence interval (CI) 1.019-1.525, P = 0.030] in reference to University of Wisconsin solution. This association was substantially increased among recipients with ischemic periods of greater than 4 h (OR 1.817, 95% CI 1.188-2.730, P = 0.005). The risks were similar between University of Wisconsin solution and Celsior solution (P = 0.454).

CONCLUSION

The use of the histidine-tryptophan-ketoglutarate solution during cold static storage for cardiac preservation is associated with increased rates of early mortality or primary graft dysfunction. Clinician discretion should guide its use, especially when prolonged ischemic times (>4 h) are anticipated.

Use of Extracorporeal Membrane Oxygenation for Primary Graft Dysfunction After Cardiac Transplantation: Results of an A Priori Ventless Approach

Primary graft dysfunction (PGD) after cardiac transplantation is a devastating complication with increasing frequency lately in the setting of donation after circulatory death (DCD). Severe PGD is commonly treated with extracorporeal membrane oxygenation (ECMO) using central or peripheral cannulation. We retrospectively reviewed the outcomes of PGD after cardiac transplantation requiring ECMO support at our center from 2015 to 2020, focused on our now preferential approach using peripheral cannulation without a priori venting. During the study period, 255 patients underwent heart transplantation at our center and 26 (10.2%) of them required ECMO for PGD. Of 24 patients cannulated peripherally 19 (79%) were alive at 30 days and 17 (71%) 1 year after transplant; two additional patients underwent central ECMO cannulation due to unfavorable size of femoral vessels and concern for limb ischemia. Successful decannulation with full graft function recovery occurred in 22 of 24 (92%) patients cannulated peripherally. Six of them had an indwelling intra-aortic balloon pump placed before the transplantation. None of the other 18 patients received a ventricular vent. In conclusion, the use of an a priori peripheral and ventless ECMO approach in patients with PGD after heart transplant is an effective strategy associated with high rates of graft recovery and survival.

Pharmacological inhibition of the cysteine protease cathepsin C improves graft function after heart transplantation in rats

BACKGROUND

Heart transplantation (HTX) is the standard treatment for end-stage heart failure. However, reperfusion following an ischemic period can contribute to myocardial injury. Neutrophil infiltration, along with the subsequent release of tissue-degrading neutrophil elastase (NE)-related serine proteases and oxygen-derived radicals, is associated with adverse graft outcomes. The inhibition of cathepsin C (CatC) has been shown to block NE-related protease activation. We hypothesized that the CatC inhibitor BI-9740 improves graft function after HTX.

METHODS

In a rat model of HTX, the recipient Lewis rats were orally administered with either a placebo (n = 12) or BI-9740 (n = 11, 20 mg/kg) once daily for 12 days. Donor hearts from untreated Lewis rats were explanted, preserved in a cardioplegic solution, and subsequently heterotopically implanted. In vivo left-ventricular (LV) graft function was assessed after 1 h of reperfusion. The proteolytic activity of neutrophil serine proteases was determined in bone marrow lysates from BI-9740-treated and control rats. Additionally, myocardial morphological changes were examined, and heart samples underwent immunohistochemistry and western blot analysis.

RESULTS

The NE-related proteolytic activity in bone marrow cell lysates was markedly decreased in the BI-9740-treated rats compared to those of the placebo group. Histopathological lesions, elevated CatC and myeloperoxidase-positive cell infiltration, and nitrotyrosine immunoreactivity with an increased number of poly(ADP-ribose) polymerase (PARP)-1-positive cells were lowered in the hearts of animals treated with BI-9740 compared to placebo groups. Regarding the functional parameters of the implanted graft, improvements were observed in both systolic function (LV systolic pressure 110 ± 6 vs 74 ± 6 mmHg; dP/dtmax 2782 ± 149 vs 2076 ± 167 mmHg/s, LV developed pressure, at an intraventricular volume of 200 µl, p < 0.05) and diastolic function in the hearts of BI-9740 treated animals compared with those receiving the only placebo. Furthermore, the administration of BI-9740 resulted in a shorter graft re-beating time compared to the placebo group. However, this study did not provide evidence of DNA fragmentation, the generation of both superoxide anions and hydrogen peroxide, correlating with the absence of protein alterations related to apoptosis, as evidenced by western blot in grafts after HTX.

CONCLUSIONS

We provided experimental evidence that pharmacological inhibition of CatC improves graft function following HTX in rats.

Therapeutic Approaches Targeting Ferroptosis in Cardiomyopathy

The term cardiomyopathy refers to a group of heart diseases that cause severe heart failure over time. Cardiomyopathies have been proven to be associated with ferroptosis, a non-apoptotic form of cell death. It has been shown that some small molecule drugs and active ingredients of herbal medicine can regulate ferroptosis, thereby alleviating the development of cardiomyopathy. This article reviews recent discoveries about ferroptosis, its role in the pathogenesis of cardiomyopathy, and the therapeutic options for treating ferroptosis-associated cardiomyopathy. The article aims to provide insights into the basic mechanisms of ferroptosis and its treatment to prevent cardiomyopathy and related diseases.

Pulse pressure within the first 2 days of veno-arterial extracorporeal membrane oxygenation is predictive of death prior to hospital discharge, renal dysfunction requiring dialysis and pulmonary oedema

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) flows are titrated to achieve adequate perfusion while attempting to ideally maintain arterial pulse pressure (PP). We assessed risk in patients with low PP defined as <10 mmHg within the first 2 days of support.

METHODS

Demographics, haemodynamics, echocardiographic and radiological findings were recorded retrospectively in cases conducted between 2014 and 2016. Outcomes were hospital mortality, requirement for renal replacement therapy (RRT) and severe pulmonary oedema (PO).

RESULTS

Of 101 patients, 66.3% were male, mean age was 56 (range 18-71 years), mean duration of support was 6.3 days ± 4.1 days, 37.6% died prior to hospital discharge, 39.6% needed RRT and 11.9% had severe PO. Areas under the receiver operating curves of PP at 48 h for hospital mortality, RRT and severe PO were (respectively): 0.69 (95% CI 0.58-0.80, p = .001), 0.64 (95% CI 0.50-0.77, p = .044), 0.69 (95% CI 0.55-0.82, p = .009). The odds ratio for mortality, RRT, severe PO for those with low PP were (respectively) 2.8 (95% CI 1.01-7.5, p = .04), 3.1 (95% CI 1.11-8.40, p = .026), 7.6 (95% CI 2.06-27.89, p = .001). Central venous pressure, mean arterial pressure were not predictive.

CONCLUSION

PP during the first 2 days of support is predictive of clinically important outcomes in patients supported with VA-ECMO.

The role of CD38 in ischemia reperfusion injury in cardiopulmonary bypass and thoracic transplantation: a narrative review

Background and Objective

Ischemia reperfusion injury (IRI) is often the underlying cause of endothelium breakdown and damage in cardiac or transplantation operations, which can lead to disastrous post-operative consequences. Recent studies of cluster of differentiation 38 (CD38) have identified its critical role in IRI. Our objective is to provide a comprehensive overview of CD38-mediated axis, pathways, and potential CD38 translational therapies for reducing inflammation associated with cardiopulmonary bypass (CPB) or thoracic transplantation and IRI.

Methods

We conducted a review of the literature by performing a search of the PubMed database on 2 April 2023. To find relevant publications on CD38, we utilized the MeSH terms: "CD38" AND "Ischemia" OR "CD38" AND "Transplant" OR "CD38" AND "Heart" from 1990-2023. Additional papers were included if they were felt to be relevant but were not captured in the MeSH terms. We found 160 papers that met this criterion, and following screening, exclusion and consensus a total of 36 papers were included.

Key Content and Findings

CD38 is most notably a nicotine adenine dinucleotide (NAD)+ glycohydrolase (NADase), and a generator of Ca2+ signaling secondary messengers. Ultimately, the release of these secondary messengers leads to the activation of important mediators of cellular death. In the heart and during thoracic transplantation, this pathway is intimately involved in a wide variety of injuries; namely the endothelium. In the heart, activation generally results in vasoconstriction, poor myocardial perfusion, and ultimately poor cardiac function. CD38 activation also prevents the accumulation of atherosclerotic disease. During transplantation, intracellular activation leads to infiltration of recipient innate immune cells, tissue edema, and ultimately primary graft dysfunction (PGD). Specifically, in heart transplantation, extracellular activation could be protective and improve allograft survival.

Conclusions

The knowledge gap in understanding the molecular basis of IRI has prevented further development of novel therapies and treatments. The possible interaction of CD38 with CD39 in the endothelium, and the modulation of the CD38 axis may be a pathway to improve cardiovascular outcomes, heart and lung donor organ quality, and overall longevity.

Donor heart ischemic time can be extended beyond 9 hours using hypothermic machine perfusion in sheep

BACKGROUND

The global shortage of donor hearts available for transplantation is a major problem for the treatment of end-stage heart failure. The ischemic time for donor hearts using traditional preservation by standard static cold storage (SCS) is limited to approximately 4 hours, beyond which the risk for primary graft dysfunction (PGD) significantly increases. Hypothermic machine perfusion (HMP) of donor hearts has been proposed to safely extend ischemic time without increasing the risk of PGD.

METHODS

Using our sheep model of 24 hours brain death (BD) followed by orthotopic heart transplantation (HTx), we examined post-transplant outcomes in recipients following donor heart preservation by HMP for 8 hours, compared to donor heart preservation for 2 hours by either SCS or HMP.

RESULTS

Following HTx, all HMP recipients (both 2 hours and 8 hours groups) survived to the end of the study (6 hours after transplantation and successful weaning from cardiopulmonary bypass), required less vasoactive support for hemodynamic stability, and exhibited superior metabolic, fluid status and inflammatory profiles compared to SCS recipients. Contractile function and cardiac damage (troponin I release and histological assessment) was comparable between groups.

CONCLUSIONS

Overall, compared to current clinical SCS, recipient outcomes following transplantation are not adversely impacted by extending HMP to 8 hours. These results have important implications for clinical transplantation where longer ischemic times may be required (e.g., complex surgical cases, transport across long distances). Additionally, HMP may allow safe preservation of "marginal" donor hearts that are more susceptible to myocardial injury and facilitate increased utilization of these hearts for transplantation.

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.

Targeting IL-6 to prevent cardiac allograft rejection

Outcomes following heart transplantation remain suboptimal with acute and chronic rejection being major contributors to poor long-term survival. IL-6 is increasingly recognized as a critical pro-inflammatory cytokine involved in allograft injury and has been shown to play a key role in regulating the inflammatory and alloimmune responses following heart transplantation. Therapies that inhibit IL-6 signaling have emerged as promising strategies to prevent allograft rejection. Here, we review experimental and pre-clinical evidence that supports the potential use of IL-6 signaling blockade to improve outcomes in heart transplant recipients.

Risk factors for heart transplant survival with greater than 5 h of donor heart ischemic time

OBJECTIVE

Implantation of donor hearts with prolonged ischemic times is associated with worse survival. We sought to identify risk factors that modulate the effects of prolonged preservation.

METHODS

Retrospective review of the United Network for Organ Sharing database (2000-2018) to identify transplants with >5 (n = 1526) or ≤5 h (n = 35,733) of donor heart preservation. In transplanted hearts preserved for >5 h, Cox-proportional hazards identify modifiers for survival.

RESULTS

Compared to ≤5 h, transplanted patients with >5 h of preservation spent less time in status 1B (76 ± 160 vs. 85 ± 173 days, p = .027), more commonly had ischemic cardiomyopathy (42.3% vs. 38.3%, p = .002), and less commonly received a blood type O heart (45.4% vs. 50.8%, p < .001). Longer heart preservation time was associated with a higher incidence of postoperative stroke (4.5% vs. 2.5%, p < .001), and dialysis (16.4% vs. 10.6%, p < .001). Prolonged preservation was associated with a greater likelihood of death from primary graft dysfunction (2.8% vs. 1.5%, p < .001) but there was no difference in death from acute (2.0% vs. 1.7%, p = .402) or chronic rejection (2.0% vs. 1.9%, p = .618). In transplanted patients with >5 h of heart preservation, multivariable analysis identified greater mortality with ischemic cardiomyopathy etiology (hazard ratio [HR] = 1.36, p < 0.01), pre-transplant dialysis (HR = 1.84, p < .01), pre-transplant extracorporeal membrane oxygenation (ECMO, HR = 2.36, p = .09), and O blood type donor hearts (HR = 1.35, p < .01).

CONCLUSION

Preservation time >5 h is associated with worse survival. This mortality risk is further amplified by preoperative dialysis and ECMO, ischemic cardiomyopathy etiology, and use of O blood type donor hearts.

Primary Graft Dysfunction after Heart Transplantation - Unravelling the Enigma

Primary graft dysfunction (PGD) remains the main cause of early mortality following heart transplantation despite several advances in donor preservation techniques and therapeutic strategies for PGD. With that aim of establishing the aetiopathogenesis of PGD and the preferred management strategies, the new consensus definition has paved the way for multiple contemporaneous studies to be undertaken and accurately compared. This review aims to provide a broad-based understanding of the pathophysiology, clinical presentation and management of PGD.

Plasma kallikrein predicts primary graft dysfunction after heart transplant

BACKGROUND

Primary graft dysfunction (PGD) is the leading cause of early mortality after heart transplant. Pre-transplant predictors of PGD remain elusive and its etiology remains unclear.

METHODS

Microvesicles were isolated from 88 pre-transplant serum samples and underwent proteomic evaluation using TMT mass spectrometry. Monte Carlo cross validation (MCCV) was used to predict the occurrence of severe PGD after transplant using recipient pre-transplant clinical characteristics and serum microvesicle proteomic data. Putative biological functions and pathways were assessed using gene set enrichment analysis (GSEA) within the MCCV prediction methodology.

RESULTS

Using our MCCV prediction methodology, decreased levels of plasma kallikrein (KLKB1), a critical regulator of the kinin-kallikrein system, was the most predictive factor identified for PGD (AUROC 0.6444 [0.6293, 0.6655]; odds 0.1959 [0.0592, 0.3663]. Furthermore, a predictive panel combining KLKB1 with inotrope therapy achieved peak performance (AUROC 0.7181 [0.7020, 0.7372]) across and within (AUROCs of 0.66-0.78) each cohort. A classifier utilizing KLKB1 and inotrope therapy outperforms existing composite scores by more than 50 percent. The diagnostic utility of the classifier was validated on 65 consecutive transplant patients, resulting in an AUROC of 0.71 and a negative predictive value of 0.92-0.96. Differential expression analysis revealed a enrichment in inflammatory and immune pathways prior to PGD.

CONCLUSIONS

Pre-transplant level of KLKB1 is a robust predictor of post-transplant PGD. The combination with pre-transplant inotrope therapy enhances the prediction of PGD compared to pre-transplant KLKB1 levels alone and the resulting classifier equation validates within a prospective validation cohort. Inflammation and immune pathway enrichment characterize the pre-transplant proteomic signature predictive of PGD.

Impact of increased donor distances following adult heart allocation system changes: A single center review of 1-year outcomes

BACKGROUND

On October 18, 2018, several changes to the donor heart allocation system were enacted. We hypothesize that patients undergoing orthotopic heart transplantation (OHT) under the new allocation system will see an increase in ischemic times, rates of primary graft dysfunction, and 1-year mortality due to these changes.

METHODS

In this single-center retrospective study, we reviewed the charts of all OHT patients from October 2017 through October 2019. Pre- and postallocation recipient demographics were compared. Survival analysis was performed using the Kaplan-Meier method.

RESULTS

A total of 184 patients underwent OHT. Recipient demographics were similar between cohorts. The average distance from donor increased by more than 150 km (p = .006). Patients in the postallocation change cohort demonstrated a significant increase in the rate of severe left ventricle primary graft dysfunction from 5.4% to 18.7% (p = .005). There were no statistically significant differences in 30-day mortality or 1-year survival. Time on the waitlist was reduced from 203.8 to 103.7 days (p = .006).

CONCLUSIONS

Changes in heart allocation resulted in shorter waitlist times at the expense of longer donor distances and ischemic times, with an associated negative impact on early post-transplantation outcomes. No significant differences in 30-day or 1-year mortality were observed.

Circulating growth differentiation factor-15 as a novel biomarker in heart transplant

Aims

This study aimed to examine (i) whether circulating growth differentiation factor‐15 (GDF‐15) is associated with acute cellular cardiac allograft rejection (ACR); (ii) a longitudinal trend of GDF‐15 after heart transplantation; and (iii) the prognostic value of GDF‐15 in predicting a composite outcome of severe primary graft dysfunction (PGD) and 30 day mortality post‐transplant.

Methods and results

Serum samples were collected before heart transplantation and at every endomyocardial biopsy (EMB) post‐heart transplantation in de novo transplant patients. A total of 60 post‐transplant serum samples were matched to the corresponding EMBs. Seven (12%) were considered International Society for Heart Lung Transplantation Grade 1R ACR, and one (2%) was identified as Grade 2R ACR. GDF‐15 levels in patients with ACR were not different from those in the non‐rejection group (6230 vs. 6125 pg/mL, P = 0.27). GDF‐15 concentration gradually decreased from 8757 pg/mL pre‐transplant to 5203 pg/mL at 4 weeks post‐transplant. The composite adverse outcome of PGD and 30 day mortality was significantly associated with increased post‐operative GDF‐15 (odds ratio: 40; 95% confidence interval: 2.01–794.27; P = 0.005) and high inotrope score post‐transplant (odds ratio: 18; 95% confidence interval: 1.22–250.35; P = 0.01).

Conclusions

Circulating GDF‐15 concentration was markedly elevated in patients with end‐stage heart failure and decreased after heart transplantation. GDF‐15 was significantly associated with post‐transplant PGD and mortality. A lack of association between ACR and GDF‐15 did not support routine use of GDF‐15 as a biomarker to detect ACR. However, GDF‐15 may be potentially useful to determine heart transplant recipients at high risk for adverse post‐transplant outcomes. We suggest that GDF‐15 levels in recipient serum can provide risk stratification for severe PGD including death during post‐operative period. This novel biomarker may serve to inform and guide timely interventions against severe PGD and adverse outcomes during the first 4 weeks after transplantation. Further studies to support the utility of GDF‐15 in heart transplantation are required.

Primary Graft Dysfunction After Isolated Heart Transplantation - Incidence, Risk Factors, and Clinical Implications Based on a Single-Center Experience

BACKGROUND

Since the international consensus on primary graft dysfunction (PGD) following heart transplantation (HT) was reported in 2014, few clinical studies have been reported. We aimed to analyze the incidence, predictive factors, and clinical implications of PGD following the International Society of Heart and Lung Transplant criteria in a single center.Methods and Results:This study enrolled 570 consecutive adult patients undergoing isolated HT between November 1992 and December 2017. Under a new set of criteria, PGD-left ventricle (PGD-LV) occurred in 35 patients (6.1%; mild, n=1 [0.2%]; moderate, n=14 [2.5%]; severe, n=20 [3.5%]), whereas PGD-right ventricle (PGD-RV) occurred in 3 (0.5%). Multivariable analysis demonstrated that preoperative admission (odds ratio [OR] 4.20; 95% confidence interval [CI] 1.24-14.26; P=0.021), preoperative extracorporeal membrane oxygenation (OR 4.03; 95% CI 1.75-9.26; P=0.001), and prolonged total ischemic time (OR 1.09; 95% CI 1.02-1.15; P=0.006) were significant predictors of moderate to severe PGD-LV. Moderate to severe PGD-LV was an independent and significant risk factor for early death (OR 55.64; 95% CI 11.65-265.73; P<0.001), with its effects extending up to 3 months after HT.

CONCLUSIONS

Moderate to severe PGD-LV, as defined by the new guidelines, is an important predictor of early mortality, with effects extending up to 3 months after HT. Efforts to reduce the occurrence of moderate to severe PGD-LV may lead to better outcomes.

Cardiac transplantation in adult congenital heart disease with prior sternotomy

BACKGROUND

Adult congenital heart disease (ACHD) patients who require orthotopic heart transplantation are surgically complex due to anatomical abnormalities and multiple prior surgeries. In this study, we investigated these patients' outcomes using our institutional database.

METHODS

ACHD patients who had prior intracardiac repair and subsequent heart transplant were included (2008-2018). Adult patients without ACHD were extracted as a control. A comparison of patients with functional single ventricular (SV) and biventricular (BV) hearts was performed.

RESULTS

There were 9 SV and 24 BV patients. The SV group had higher central venous pressure/pulmonary capillary wedge pressure (P = .028), hemoglobin concentration (P = .010), alkaline phosphatase (P = .022), and were more likely to have liver congestion (P = .006). Major complications included infection in 16 (48.5%), temporary dialysis in 12 (36.4%), and graft dysfunction requiring perioperative mechanical support in 7 (21.2%). Overall in-hospital mortality was 15.2%. Kaplan-Meier analysis showed a higher, but not statistically significant, survival after 10 years between the ACHD and control groups (ACHD 84.9% vs. control 67.5%, P = .429). There was no significant difference in 10-year survival between SV and BV groups (78% vs. 88%, P = .467).

CONCLUSIONS

Complex ACHD cardiac transplant recipients have a high incidence of early morbidities after transplantation. However, long-term outcomes were acceptable.

The effects of increased donor support time from organ donation referral to donor procurement on heart transplant recipient survival

INTRODUCTION

Given the known deleterious cardiac effects of brain death (BD) physiology, we hypothesized that time from cardiac donation referral to procurement (donor support time [DST]), would negatively impact cardiac transplant recipient survival.

METHODS

The United Network for Organ Sharing database was queried from 2007 to 2018, identifying 22,593 donor hearts for analysis. Multivariate logistic models for 30-day and 1-year survival, as well as Cox models for overall survival and posttransplant rejection, were used to assess adjusted outcomes.

RESULTS

median DST was 3 days (interquartile range: 2-5 days). Ischemic time; distance between donor and recipient hospitals; and recipient age, creatinine, waitlist time, and length of stay were adjusted predictors of survival and rejection. DST was not associated with either outcome in aggregate; however, differential association by donor race was identified, with DST in any race recipient associated with 4% higher odds of 1-year mortality (p = .001; p value for interaction .005) but only a trend towards worse overall mortality (p = .064; p value for interaction .046).

CONCLUSION

Thus, duration of exposure to BD physiology may have a differential impact on recipient outcomes based on donor race, suggesting that additional research is needed on donor immunologic, socioeconomic, and healthcare access factors that may impact cardiac transplant recipient outcomes.

Postoperative vasoactive inotropic score is predictive of outcomes in pediatric heart transplantation

Vasoactive inotrope score (VIS) is scarcely studied in pediatric orthotopic heart transplantation (pOHT). We conducted a retrospective review of pOHT (<21 years) recipients. Max VIS and mean VIS were calculated at 0-24 and 24-48 hours post-pOHT. Patients were divided into groups based on ISHLT guidelines: high (>10) and low (≤10). In our group (n = 104), patients with high max and mean VIS groups at 0-24 and 24-48 hours had longer bypass times (high: >130 minutes; low: <108 minutes; P < .05) and high max and mean VIS groups at 0-24 hours had longer ischemic times (high: >215 minutes; low: <192 minutes; P < .05). Patients with high max and mean VIS at 0-24 and 24-48 hours had longer hospital stay, ventilation, inotrope duration, more cardiac events, and acute kidney injury postoperatively (P < .05). High max VIS at 24-48 hours and high mean VIS at 24-48 hours had higher 3-year mortality (P = .04; P = .02). Multivariate analysis confirmed the association of VIS with short-term outcomes. However, VIS was not identified as an independent predictor of mortality. The ROC curve exhibits 10 as the ideal cutoff with area under the curve >0.8 for primary graft dysfunction (PGD).

Extracorporeal Membrane Oxygenation after Heart Transplantation: Impact of Type of Cannulation

BACKGROUND

Primary graft dysfunction (PGD) is a common cause of early death after heart transplantation (htx). The use of extracorporeal life support (ECLS) after htx has increased during the last years. It is still discussed controversially whether peripheral cannulation is favorable compared to central cannulation. We aimed to compare both cannulation techniques.

METHODS

Ninety patients underwent htx in our department between 2010 and 2017. Twenty-five patients were treated with ECLS due to PGD (10 central extracorporeal membrane oxygenator [cECMO] and 15 peripheral extracorporeal membrane oxygenator [pECMO] cannulation). Pre- and intraoperative parameters were comparable between both groups.

RESULTS

Thirty-day mortality was comparable between the ECLS-groups (cECMO: 30%; pECMO: 40%, p = 0.691). Survival at 1 year (n = 18) was 40 and 30.8% for cECMO and pECMO, respectively. The incidence of postoperative renal failure, stroke, limb ischemia, and infection was comparable between both groups. We also did not find significant differences in duration of mechanical ventilation, intensive care unit stay, or in-hospital stay. The incidence of bleeding complications was also similar (cECMO: 60%; pECMO: 67%). Potential differences in support duration in pECMO group (10.4 ± 9.3 vs. 5.7 ± 4.7 days, p = 0.110) did not reach statistical significance.

CONCLUSIONS

In patients supported for PGD, peripheral and central cannulation strategies are safe and feasible for prolonged venoarterial ECMO support. There was no increase in bleeding after central implantation. With regard to the potential complications of a pECMO, we think that aortic cannulation with tunneling of the cannula and closure of the chest could be a good option in patients with PGD after htx.

Coronary revascularization after heart transplant - the search for prognostic factors

INTRODUCTION

Survival after heart transplantation (HTX) is extended due to continuous improvement of medical care, allowing enough time for coronary artery vasculopathy to develop. Data on the clinical outcome of cardiac transplantation patients after percutaneous coronary intervention (PCI) are still not extensively explored. The aim of our study was to assess whether heart transplantation itself compromises the outcome in patients undergoing percutaneous coronary intervention and to assess survival rates as well as major cardiovascular complications in heart transplant recipients who had undergone PCI.

MATERIAL AND METHODS

Thirty-three heart transplant recipients who had undergone PCI in the years 2005 to 2015 in a single center were matched by age, sex and main risk factors of arteriosclerosis with 33 controls without heart transplant history. Mean age of patients was 54.6 ±11.4 years in the HTX group and 58.8 ±10.8 years in controls. Median time from heart transplant to PCI was 13 years (4.4-22 years). Case and control groups did not differ in terms of standard risk factors of coronary artery disease, apart from chronic kidney disease, which was present in 70% of patients after heart transplantation, and dyslipidemia, which was present in 91% of control subjects.

RESULTS

Patients after HTX had worse survival compared to controls (p = 0.04). When adjusted for comorbidities in the Cox regression model, there was no significant difference in survival between cardiac transplant recipients and the control group (HR = 1.06; 95% CI: 0.10-11.24). Chronic renal disease was a significant predictor of all-cause mortality (HR = 29.9; 95% CI: 2.3-393). Considering other endpoints, HTX patients had considerably higher incidence of severe bleeding compared to the control group (27% vs. 3%, p < 0.05).

CONCLUSIONS

There was no significant difference in myocardial infarction rate, revascularization or hospitalization rates.

Case report - coronary vasospasm in transplanted heart: a puzzling phenomenon

Background

Coronary artery spasm (CAS) is an underdiagnosed disease especially in heart transplant patients, and in those patients the etiology and pathophysiology remain largely unknown, although it has been associated with cardiac allograft vasculopathy or graft rejection.

Case presentation

We report the case of a heart-transplant patient whose cardiac graft experienced two coronary vasospasms: the first before transplantation, and the other at one-month of a postoperative course complicated by primary graft failure.

Conclusion

Our case illustrates that a transplanted heart predisposed with coronary vasospasm may suffer from early relapse in the recipient despite of complete post-surgical autonomic denervation. Exacerbated endothelial dysfunction of the donor heart after transplant, with the addition of systemic factors in the recipient may be involved in the genesis of this puzzling phenomenon.

Primary graft dysfunction after heart transplantation: Outcomes and resource utilization

BACKGROUND

A unified definition of primary graft dysfunction (PGD) after heart transplantation was adopted in 2014, with moderate and severe PGD defined as a need for mechanical circulatory support. While risk factors for PGD are well identified, outcomes and resource utilization have not been well-studied. We examined the resource utilization and associated costs with PGD.

METHODS

All adult heart transplantations (2001-2016) from a statewide Society of Thoracic Surgery database were analyzed by dividing them into two groups-with PGD (requiring mechanical circulatory support) and without PGD.

RESULTS

Of the 718 heart transplants, 110 (15.3%) patients developed PGD. Prevalence of PGD for the study duration ranged from 3.7% to 22.7% with no significant trend. The most frequently used mechanical circulatory support device was intra-aortic balloon pump (88%), followed by extracorporeal membrane oxygenation (17%), and catheter-based circulatory support devices (3%). There were no significant differences in demographics or preoperative variables between the two groups. Resource utilization such as total intensive care unit hours, ventilation hours, reoperation for bleeding, blood product transfusions, and length of stay were significantly higher in the PGD group. Postoperative complications were also higher in PGD group including operative mortality (31.8% vs 3.8%, P < .0001). The median cost of heart transplantation was significantly higher in the PGD group $229 482 ($126 044-$388 889) vs $101 788 ($72 638-$181 180) P < .0001.

CONCLUSION

Primary graft dysfunction following heart transplantation developed in 15% of patients. Patients with PGD had significantly higher complications, resource utilization, and mortality. Preventive measures to address the development of PGD would reduce resource utilization and improve outcomes.

Cyclocreatine protects against ischemic injury and enhances cardiac recovery during early reperfusion

Introduction: A critical mechanism of how hypoxia/ischemia causes irreversible myocardial injury is through the exhaustion of adenosine triphosphate (ATP). Cyclocreatine (CCr) and its water-soluble salt Cyclocreatine-Phosphate (CCrP) are potent bioenergetic agents that preserve high levels of ATP during ischemia. Areas covered: CCr and CCrP treatment prior to the onset of ischemia, preserved high levels of ATP in ischemic myocardium, reduced myocardial cell injury, exerted anti-inflammatory and anti-apoptotic activities, and restored contractile function during reperfusion in animal models of acute myocardial infarction (AMI), global cardiac arrest, cardiopulmonary bypass, and heart transplantation. Medline and Embase (1970 - Feb 2019), the WIPO databank (up to Feb 2019); no language restriction. Expert opinion: This review provides the basis for a number of clinical applications of CCrP and CCr to minimize ischemic injury and necrosis. One strategy is to administer CCrP to AMI patients in the pre-hospital phase, as well as during, or after Percutaneous Coronary Intervention (PCI) procedure to potentially achieve protection of the myocardium, reduce infarcted-size, and, thus, limit the progression to heart failure. Another clinical applications are in predictable myocardial ischemia where pretreatment with CCrP would likely improve outcome and quality of life of patients who will undergo cardiopulmonary bypass for coronary revascularization and end-stage heart failure patients scheduled for heart transplantation.

Primary graft dysfunction after heart transplantation: a thorn amongst the roses

Primary graft dysfunction (PGD) remains the leading cause of early mortality post-heart transplantation. Despite improvements in mechanical circulatory support and critical care measures, the rate of PGD remains significant. A recent consensus statement by the International Society of Heart and Lung Transplantation (ISHLT) has formulated a definition for PGD. Five years on, we look at current concepts and future directions of PGD in the current era of transplantation.

Early Graft Dysfunction Following Heart Transplant: Prevention and Management

Heart transplant can be considered as the “gold standard” treatment for end-stage heart failure, with nearly 5.7 million adults in the United States carrying a diagnosis of heart failure. According to the International Society for Heart and Lung Transplantation registry, nearly 3300 orthotopic heart transplants were performed in 2016 in North America. In spite of significant improvements in overall perioperative care of heart transplant recipients for the past few decades, the risk of 30-day mortality remains 5% to 10%, primarily related to early failure of the allograft. Early graft dysfunction (EGD) occurs within 24 hours after transplant, manifesting as left ventricular dysfunction, right ventricular dysfunction, or biventricular dysfunction. EGD is further classified into primary and secondary graft dysfunction. This review focus on describing overall incidences of EGD, potential risk factors associated with EGD, perioperative preventive measures, and various management options.

Primary graft failure after cardiac transplantation: prevalence, prognosis and risk factors

OBJECTIVES

Primary graft failure (PGF) is a common and devastating complication, despite the advances in perioperative treatment. We aim to evaluate the prevalence of PGF and its impact on survival and to explore associated risk factors.

METHODS

From November 2003 through December 2015, 290 patients submitted to cardiac transplantation were classified into non-PGF (243; 84%) and PGF (47; 16%) groups. The characteristics of the recipients were similar regarding age (54.6 ± 10.6 vs 54.0 ± 9.4 years; P = 0.74), male gender (78.2% vs 72.3%; P = 0.38) and transpulmonary gradient (9.4 ± 4.2 vs 10.5 ± 5.6 mmHg; P = 0.15); donors to the PGF group had similar age (35.5 ± 11.4 vs 37.5 ± 10.7 years; P = 0.27) but were predominantly female (21% vs 42.6%; P = 0.002).

RESULTS

Mean ischaemic (89.0 ± 36.8 vs 103.3 ± 44.7 min; P = 0.019) and cardiopulmonary bypass (92.8 ± 14.5 vs 126.3 ± 62.4 min; P < 0.001) times were longer in the PGF group. Length of hospital stay was 13.5 ± 7.5 vs 28.9 ± 35.2 days (P= 0.005). Hospital mortality was 4.1% [1.6% for non-PGF and 17% for PGF (P < 0.001)]. Survival at 1, 5 and 10 years was 95.5 ± 1.3% vs 55.3 ± 7.3%, 84.1 ± 2.5% vs 47.4 ± 7.6% and 67.1 ± 3.8% vs 14.4 ± 12%, respectively (P < 0.001). Risk factors for PGF were female donor [odds ratio (OR): 2.56; 95% confidence interval (CI): 1.29-5.09; P = 0.007], total ischaemic time (OR: 1.01; 95% CI: 1.00-1.02; P = 0.032) and preoperative mechanical extracorporeal circulatory support (OR: 11.90; 95% CI: 2.62-54.12; P = 0.001).

CONCLUSIONS

Our results demonstrate that PGF is associated with poor outcomes that extend beyond the 1st month and the 1st year after heart transplantation. We found female donor, total ischaemic time and preoperative mechanical extracorporeal circulatory support to be risk factors for PGF.

Bioengineering approaches to organ preservation ex vivo

IMPACT STATEMENT

Over the past several decades, ex vivo perfusion has emerged as a promising technology for the assessment, preservation, and recovery of donor organs. Many exciting pre-clinical findings have now been translated to clinical use, and successful transplantation following ex vivo perfusion has been achieved for heart, lung, and liver. While machine perfusion provides distinct advantages over traditional cold preservation, many challenges remain, including that of long-term (multi-day) ex vivo support. Here, we provide an overview of the current status of ex vivo machine perfusion in the pre-clinical and clinical setting and share our perspective on the future direction of the field.

Common Postoperative Heart Transplant Complications

Heart failure or congestive heart failure remains a major public health concern on the global scale. End-stage heart failure is a severe disease where the heart is unable to pump enough oxygen and nutrients to other tissues and organs of the body. When the lines of treatment of heart failure such as lifestyle adjustments, medical management, and device therapy fail, a patient may be deemed a candidate for heart transplantation. This article reviews the history of heart transplantation, complications post-heart transplantation, and nursing management considerations for the immediate period after heart transplant surgery.

Impact of Coronary Artery Calcification in the Donor Heart on Transmitted Coronary Artery Disease in Heart Transplant Recipients

BACKGROUND

Coronary artery disease (CAD) after heart transplantation (HTx) develops as a combination of donor-transmitted coronary atherosclerosis (DTCA) and cardiac allograft vasculopathy. Assessing donor CAD before procurement is important. Because coronary artery calcification (CAC) is a predictor for CAD, donor-heart CAC is usually evaluated to estimate the risk of donor CAD. The usefulness of CAC for predicting DTCA, however, is not known. Methods and Results: Sixty-four HTx recipients whose donor underwent chest computed tomography before procurement or ≤2 weeks after HTx and who underwent coronary angiography and intravascular ultrasound (IVUS) ≤3 months after HTx were enrolled. Eight patients had CAC (CAC group) and 56 patients did not have CAC (no-CAC group). Patients in the CAC group were significantly older and had a higher prevalence of maximum intimal thickness (MIT) of the coronary artery ≥0.5 mm at initial IVUS than patients in the no-CAC group (100% vs. 55%, P=0.02). Adverse cardiac events and death were not significantly different. Everolimus tended to be used more often in the CAC group.

CONCLUSIONS

Donor-heart CAC is a significant predictor for MIT of the coronary artery ≥0.5 mm after HTx. The presence of CAC, however, is not associated with future cardiac events. The higher prevalence of everolimus use in the CAC group may have affected the results.

Salvage of severe primary graft dysfunction following heart transplantation using extracorporeal life support

Primary graft dysfunction (PGD) is the leading cause of early mortality after heart transplantation. Typically, mechanical circulatory support is necessary to provide hemodynamic support and to enable graft recovery. However, both the reported incidence of PGD and the reported salvage rates with extracorporeal membrane oxygenation (ECMO) vary widely. This may partly be due to variations in the definition of PGD and its levels of severity. We analyzed a prospectively maintained database of 255 transplant recipients at our institution to determine the effectiveness of ECMO support in those who develop severe PGD as defined by the International Society for Heart and Lung Transplantation consensus guidelines. Nineteen (7.5%) patients (aged 32-69 years) developed severe PGD and were treated with veno-arterial (VA) ECMO, which was initiated in the operating room at the time of transplant in most patients. The majority received VA ECMO through femoral cannulation. Two patients required veno-venous ECMO for respiratory support after VA ECMO separation. The 30-day in-hospital survival rate following transplantation was 63% (n = 12). In conclusion, ECMO proved to be a viable option for early hemodynamic support in patients with severe PGD and has become our preferred modality for mechanical circulatory support in these patients.

Long distance heart transplantation: a tale of two cities

In this 'paired' case report, we describe two heart transplants performed 3 days apart at our centre. Both cases involved very prolonged transportation time of the donor heart. In one case, the donor heart was transported in an ice chest, while in the other case the organ was transported using a normothermic ex vivo perfusion (NEVP) system. The additional retrieval costs incurred by the use NEVP were more than offset by the reduction in subsequent inpatient costs.

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

Changes in heart transplantation (HT) donor and recipient demographics may influence the incidence of primary graft dysfunction (PGD). We conducted a retrospective study to evaluate PGD incidence, trends, and associated risk factors by analyzing consecutive adult patients who underwent HT between January 2009 and December 2014 at our institution. Patients were categorized as having PGD using the International Society for Heart & Lung Transplantation (ISHLT)-defined criteria. Variables, including clinical and demographic characteristics of donors and recipients, were selected to assess their independent association with PGD. A time-trend analysis was performed over the study period. Three-hundred seventeen patients met inclusion criteria. Left ventricular PGD, right ventricular PGD, or both, were observed in 99 patients (31%). Risk factors independently associated with PGD included ischemic time, recipient African American race, and recipient amiodarone treatment. Over the study period, there was no change in the PGD incidence; however, there was an increase in the recipient pretransplantation use of amiodarone. The rate of 30-day mortality was significantly elevated in those with PGD versus those without PGD (6.06% vs 0.92%, P = .01). Despite recent advancements, incidence of PGD remains high. Understanding associated risk factors may allow for implementation of targeted therapeutic interventions.

Utilization and Outcomes of Temporary Mechanical Circulatory Support for Graft Dysfunction After Heart Transplantation

Graft dysfunction is the main cause of early mortality after heart transplantation. In cases of severe graft dysfunction, temporary mechanical circulatory support (TMCS) may be necessary. The aim of this systematic review was to examine the utilization and outcomes of TMCS in patients with graft dysfunction after heart transplantation. Electronic search was performed to identify all studies in the English literature assessing the use of TMCS for graft dysfunction. All identified articles were systematically assessed for inclusion and exclusion criteria. Of the 5,462 studies identified, 41 studies were included. Among the 11,555 patients undergoing heart transplantation, 695 (6.0%) required TMCS with patients most often supported using venoarterial extracorporeal membrane oxygenation (79.4%) followed by right ventricular assist devices (11.1%), biventricular assist devices (BiVADs) (7.5%), and left ventricular assist devices (LVADs) (2.0%). Patients supported by LVADs were more likely to be supported longer (p = 0.003), have a higher death by cardiac event (p = 0.013) and retransplantation rate (p = 0.015). In contrast, patients supported with BiVAD and LVAD were more likely to be weaned off support (p = 0.020). Overall, no significant difference was found in pooled 30 day survival (p = 0.31), survival to discharge (p = 0.19), and overall survival (p = 0.51) between the subgroups. Temporary mechanical circulatory support is an effective modality to support patients with graft dysfunction after heart transplantation. Further studies are needed to establish the optimal threshold and strategy for TMCS and to augment cardiac recovery and long-term survival.

Development of a cardiac loading device to monitor cardiac function during ex vivo graft perfusion

Background

Ex vivo heart perfusion systems, allowing continuous perfusion of the coronary vasculature, have recently been introduced to limit ischemic time of donor hearts prior to transplantation. Hearts are, however, perfused in an unloaded manner (via the aorta) and therefore, cardiac contractile function cannot be reliably evaluated.

Objectives

We aim to develop a ventricular loading device that enables monitoring of myocardial function in an ex vivo perfusion system. In this initial study, was to develop a prototype for rat experimentation.

Methods

We designed a device consisting of a ventricular balloon and a reservoir balloon, connected through an electronic check valve, which opens and closes in coordination with changes in ventricular pressure. All balloons were produced in our laboratory and their properties, particularly pressure-volume relationships, were characterized. We developed a mock ventricle in vitro test system to evaluate the device, which was ultimately tested in ex vivo perfused rat hearts.

Results

Balloon production was consistent and balloon properties were maintained over time and with use on the device. Results from in vitro and ex vivo experiments show that the device functions appropriately; hemodynamic function can be measured and compares well to measurements made in an isolated, working (loaded) rat heart preparation.

Conclusions

Our cardiac loading device appears to reliably allow measurement of several left ventricular hemodynamic parameters and provides the opportunity to control ventricular load.

Cardiac and pulmonary donor procurement

PURPOSE OF REVIEW

Within the United States, donor heart and lung procurement varies between institutions and among surgeons within the same institution sometimes. The purpose of this article is to review the history of donor heart and lung procurement, the surgical techniques, and pitfalls.

RECENT FINDINGS

The current article covers the important intraoperative evaluation of the donor heart and lungs at the procurement hospital and the surgical pitfalls that can be prevented to ensure good procurement of donor heart and lungs.

SUMMARY

The current article provides a review of the history of donor procurement. The article will also provide recommendations for surgical techniques and to prevent possible complications of donor procurement at the time of surgery.

Direct Ultrasound of the Pulmonary Artery Helps Diagnose a Rare Cause of Right Ventricular Failure After Heart Transplantation: A Case Report

Pulmonary artery anastomosis stenosis is a rare cause of right ventricular failure after orthotopic heart transplantation. In this case report, direct ultrasound of the pulmonary artery helped diagnose stenosis at a location not visible on transesophageal echocardiography or even with standard epicardial ultrasound views. It is important to evaluate all vascular anastomoses after heart or lung transplantation because surgical revision of these lesions is facile, but if left undiagnosed, significant morbidity or mortality is likely.

A New Multi-Mode Perfusion System for Ex Vivo Heart Perfusion Study

Ex vivo heart perfusion has been shown to be an effective means of facilitating the resuscitation and assessment of donor hearts for cardiac transplantation. Over the last ten years however, only a few ex vivo perfusion systems have been developed for this application. While results have been promising, a system capable of facilitating multiple perfusion strategies on the same platform has not yet been realized. In this paper, the design, development and testing of a novel and modular ex vivo perfusion system is described. The system is capable of operating in three unique primary modes: the traditional Langendorff Mode, Pump-Supported Working-Mode, and Passive Afterload Working-Mode. In each mode, physiological hemodynamic parameters can be produced by managing perfusion settings. To evaluate heart viability, six experiments were conducted using porcine hearts and measuring several parameters including: pH, aortic pressure, lactate metabolism, coronary vascular resistance (CVR), and myocardial oxygen consumption. Pressure-volume relationship measurements were used to assess left ventricular contractility in each Working Mode. Hemodynamic and metabolic conditions remained stable and consistent across 4 h of ex vivo heart perfusion on the ex vivo perfusion system, validating the system as a viable platform for future development of novel preservation and assessment strategies.