The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: Thirty-eighth adult heart transplantation report - 2021; Focus on recipient characteristics

Artificial intelligence-derived cardiac ageing is associated with cardiac events post-heart transplantation

Aims

An artificial intelligence algorithm detecting age from 12-lead electrocardiogram (ECG) has been suggested to reflect 'physiological age'. An increased physiological age has been associated with a higher risk of cardiac mortality in the non-transplant population. We aimed to investigate the utility of this algorithm in patients who underwent heart transplantation (HTx).

Methods and results

A total of 540 patients were studied. The average ECG ages within 1 year before and after HTx were used to represent pre- and post-HTx ECG ages. Major adverse cardiovascular event (MACE) was defined as any coronary revascularization, heart failure hospitalization, re-transplantation, and mortality. Recipient pre-transplant ECG age (mean 63 ± 11 years) correlated significantly with recipient chronological age (mean 49 ± 14 years, R = 0.63, P < 0.0001), while post-transplant ECG age (mean 54 ± 10 years) correlated with both the donor (mean 32 ± 13 years, R = 0.45, P < 0.0001) and the recipient ages (R = 0.38, P < 0.0001). During a median follow-up of 8.8 years, 307 patients experienced MACE. Patients with an increase in ECG age post-transplant showed an increased risk of MACE [hazard ratio (HR): 1.58, 95% confidence interval (CI): (1.24, 2.01), P = 0.0002], even after adjusting for potential confounders [HR: 1.58, 95% CI: (1.19, 2.10), P = 0.002].

Conclusion

Electrocardiogram age-derived cardiac ageing after transplantation is associated with a higher risk of MACE. This study suggests that physiological age change of the heart might be an important determinant of MACE risk post-HTx.

Overcoming challenges in patient selection and monitoring in combined heart and kidney transplantation

Combined heart-kidney transplantation (HKT) is a growing therapeutic strategy in patients with advanced heart failure (HF) and concomitant chronic kidney disease (CKD). Although patients with advanced HF and need for chronic haemodialysis have a clear indication for combined HKT, challenges to current practice lie in identifying those patients with severely depressed kidney function, which will not recover kidney function after restoration of appropriate haemodynamic conditions following heart transplantation (HT) alone. Because of the paucity of available organs, maximisation of kidney graft utility whilst minimising the operative risks associated with combined transplantation is mandatory. The benefits of HKT go beyond the mere restoration of kidney function. Data from registry analysis show that HKT improves overall survival in patients with CKD, as compared to heart transplant only, and it is associated with reduced incidence of heart allograft rejection, likely through the promotion of host immune tolerance mechanisms. In patients not requiring chronic dialysis, kidney-after-heart strategy may be explored, instead of combined HKT, in particular when the aetiology of CKD is unclear. This indeed allows for monitoring and gaging of indications for combined transplantation in the postoperative period. This approach however should be matched with priority listing for kidney transplantation given the high waitlist mortality in heart transplant recipients with associated CKD. The use of kidney machine perfusion may represent an additional tool to optimise the outcome of HKT, allowing more time to stabilise the patient after HT surgery.

Diabetes Is an Independent Risk Factor for Cancer after Heart and/or Lung Transplantation

Background: De novo cancers are feared complications after heart or lung transplantation. Recent data suggest that diabetes mellitus (DM) might also be a risk factor for cancer. We hypothesized that transplanted diabetic patients are at greater risk of developing cancer compared to non-diabetic ones. Methods: We reviewed 353 patients post-heart and/or -lung transplantation from our center between October 1999 and June 2021. Patients with follow-up <180 days (n = 87) were excluded from the analysis. The remaining 266 patients were divided into patients who had preoperative DM (n = 88) or developed it during follow-up (n = 40) and patients without DM (n = 138). Results: The diabetic cohort showed higher rates of malignancies in all patients (30.33 vs. 15.97%, p = 0.005) and in the matched population (31.9 vs. 16.1%, p < 0.001). There were also significantly more solid tumors (17.9 vs. 9.4%, p = 0.042; matched: 16.6 vs. 9.1%, p = 0.09) The presence of diabetes was associated with a 13% increased risk of cancer when compared to non-diabetic patients. New-onset post-transplant diabetes doubled the likelihood of cancer development. Conclusions: Pre-transplant diabetes mellitus increases the risk of cancer after heart and/or lung transplantation. However, new-onset diabetes after transplantation is associated with a much greater cancer risk. This information is relevant for screening during follow-up.

Cardiac donors with renal impairment: Usage and outcomes after heart transplant

INTRODUCTION

Utilization of hearts from donors with significant renal dysfunction and the impact of donor renal function on outcomes following heart transplant (HT) is unknown. We sought to investigate the trends, characteristics and outcomes associated with these donor hearts and the impact of donor renal function on survival and graft failure in adult HT recipients.

METHODS

We reviewed the Scientific Registry of Transplant Recipients and summarized trends, characteristics and outcomes of hearts from adult donors by renal impairment. Single-organ HTs were evaluated and stratified by donors with eGFRs< and ≥30 mL/min. We constructed Cox proportional hazards regression models to compare time-to-mortality over 30-day, 1-year, 3-year and 5-year time-horizons between groups, and the association of donor eGFR group with graft failure.

RESULTS

A total of 162,586 adults were evaluated for cardiac donation, of which, 22,780 (14%) had an eGFR≤30 mL/min. Donors with an eGFR≤30 ml/min increased over time, from 7.2% (358/4,966) in 2000 to a high of 19.5% (2,283/11,728) in 2020. Such donors were significantly more likely discarded (not offered (7.9% vs. 9.8%, p<0.001) or accepted (62.6% vs. 72.2%, p<0.001), and less likely to be transplanted (18.0 % vs. 29.5%; p<0.001). Of 41,044 HT recipients, 3,906 (9.5%) had hearts from such donors. Primary graft failure was similar between groups (OR 1.20, 95% CI 0.91-1.58; p = 0.1) while adjusted mortality was lower for recipients from donors with eGFR ≤30 ml/min.

CONCLUSIONS

More than two-third of hearts from donors with renal dysfunction are discarded. Recipients from donors with renal dysfunction sustained lower mortality post HT during the study period. Increased evaluation and utilization of donors with renal dysfunction has the potential to expand the critically low donor pool. This article is protected by copyright. All rights reserved.

Pediatric heart transplantation: The past, the present, and the future

Heart transplantation (HTx) has a storied past, with origins dating back to the early twentieth century and the first pediatric orthotopic heart transplant performed in 1967 on a neonate with Ebstein abnormality. Today, approximately 500 pediatric HTx are performed annually, with survival times now measured in decades rather than days or weeks. In large part, advances in immunosuppression, critical care, dedicated transplant teams and mechanical circulatory support have paved the way for improvements in waitlist mortality and post-transplant survival, with future directions including the development of intracorporeal ventricular assist devices (VADs) for small children, expanding/standardizing donor criteria, and xenotransplantation.

Approaches and strategies to manage the hepatitis C virus-positive heart donor

PURPOSE OF REVIEW

Cardiac transplantation remains the treatment of choice for patients with advanced heart failure, but is limited by a donor organ shortage. Utilization of hepatitis C virus (HCV)-positive donors has been recently adopted to expand access to heart transplantation. We review the history of HCV heart transplantation, modern drug therapy, and recent outcomes.

RECENT FINDINGS

Since the advent of direct-acting antiviral (DAA) therapy, several single-center studies, and retrospective reviews have demonstrated good short-term outcomes, shorter waitlist times, and clearance of viremia with recipients of HCV-positive hearts. Two principle approaches to treatment of recipients of HCV viremic donors are utilized. In the prophylactic strategy, therapy is initiated before viremia is detected compared with the preemptive approach where initiation of DAA is delayed until after viremia is detected. Future studies are needed to address uncertainty about medium and long-term outcomes of using HCV-positive hearts and to determine the optimal treatment timing and duration.

SUMMARY

Utilization of HCV-positive donors has expanded the heart donor pool and appears safe through the early posttransplant period. We suggest that prophylactic administration of the shortest effective course of a DAA pangenotypic agent should be the current standard of care.

Biomarker-Based Assessment for Infectious Risk Before and After Heart Transplantation

Purpose of Review

Survival outcomes for heart transplant recipients have improved in recent decades, but infection remains a significant cause of morbidity and mortality. In this review, we discuss several biological markers, or biomarkers, that may be used to monitor immunologic status in this patient population.

Recent Findings

While modest, data on the utility of immune biomarkers in heart transplant recipients suggest correlation between low level of immune response and increased infection risk. More novel assays, such as the detection of circulating levels of pathogen cell-free DNA in plasma and the use of Torque teno virus load as a surrogate for net state of immunosuppression, have potential to be additional important biomarkers.

Summary

Biomarker approaches to individualize immunosuppression therapy among heart transplant recipients is a promising area of medicine. However, additional studies are needed to inform the optimal protocol in which to incorporate these biomarkers into clinical practice.

The Role of Purinergic Signaling in Heart Transplantation

Heart transplantation remains the optimal treatment option for patients with end-stage heart disease. Growing evidence demonstrates that purinergic signals mediated by purine nucleotides and nucleosides play vital roles in heart transplantation, especially in the era of ischemia-reperfusion injury (IRI) and allograft rejection. Purinergic signaling consists of extracellular nucleotides and nucleosides, ecto-enzymes, and cell surface receptors; it participates in the regulation of many physiological and pathological processes. During transplantation, excess adenosine triphosphate (ATP) levels are released from damaged cells, and driver detrimental inflammatory responses largely via purinergic P2 receptors. Ecto-nucleosidases sequentially dephosphorylate extracellular ATP to ADP, AMP, and finally adenosine. Adenosine exerts a cardioprotective effect by its anti-inflammatory, antiplatelet, and vasodilation properties. This review focused on the role of purinergic signaling in IRI and rejection after heart transplantation, as well as the clinical applications and prospects of purinergic signaling.

Trends and Characteristics of Hospitalizations in Patients with Heart Transplant

There is limited data regarding the leading causes of hospitalization among heart transplant (HT) recipients and the characteristics of these hospitalizations. We conducted a retrospective analysis of the National Inpatient Sample weighted data between January 1, 2004, and December 31, 2018, which included hospitalized adults ≥18 years with a history of HT. Primary outcomes were the 10 most common primary causes of hospitalizations, clinical characteristics, inpatient mortality, length of stay, and inflation-adjusted care costs. We divided the study population in two period (2004-2014 and 2016-2018) to report the most common causes of hospitalizations. We identified a total of 209,771 weighted hospitalizations with a history of HT between January 1, 2004, and December 31, 2018. Between 2004-2014, pneumonia (6.21%), acute or unspecified renal failure (4.94%), complication of device, implant or graft (4.66%), sepsis (4.56%), and congestive heart failure (2.94%) were the most common causes of hospitalizations for HT recipient. Between 2016-2018, sepsis (9.03%), acute or unspecific renal failure (6.27%), complication of device, implant or graft (5.16%), pneumonia (4.92%), and complications of surgical procedure or medical device (3.86%) were the most common causes of hospitalizations for HT recipient. Sepsis had the highest inpatient mortality accounting for 11.32% of inpatient mortality in the 2004-2014 period and 6% in the 2016-2018 period. In summary, infections, acute renal failure, and other transplant complications are the leading causes of hospitalization among HT recipients. Sepsis carries the highest inpatient mortality.

Impact of pretransplant bloodstream infection on clinical outcomes after heart transplantation

BACKGROUND

Active bloodstream infection (BSI) is a contraindication for heart transplantation (HT). However, some critical patients with BSI may undergo HT as a life-saving procedure. We aimed to investigate the impact of pretransplant BSI on the clinical outcomes after HT.

METHODS

We enrolled 511 consecutive patients who underwent HT between 1999 and 2019. Patients were divided into two groups based on the presence of BSI within 30 days preoperatively. Forty-three patients (8.4%) with BSI who were clinically stable and had no metastatic infection were considered for HT on an individual basis. In-hospital mortality, incidence of early postoperative BSI, length of postoperative hospital stays, and long-term survival were compared between the groups. Logistic and Cox regression analyses were performed to identify risk factors for in-hospital and 1-year mortality.

RESULTS

Patients with pretransplant BSI had a high incidence of previous cardiopulmonary resuscitation, pretransplant ventilator use, mechanical circulatory support use, renal replacement therapy, United Network for Organ Sharing status 1A, and a prolonged preoperative hospital waiting period. The in-hospital mortality rate was higher in patients with pretransplant BSI (21% versus 12%, p = 0.081), and the mortality rate was very high (33.3%) for those with BSI 0-15 days before HT. In addition, patients with pretransplant BSI had a significantly longer postoperative hospital stay than patients in the control group. However, long-term survival was similar in both groups.

CONCLUSIONS

Although pretransplant BSI was associated with higher in-hospital mortality and prolonged postoperative hospital stay, patients who survived the early period had a similar long-term prognosis. This article is protected by copyright. All rights reserved.

Gender differences in the assessment, decision making and outcomes for ventricular assist devices and heart transplantation: An analysis from a UK transplant centre

PURPOSE

There are marked gender differences in all aetiologies of advanced heart failure. We sought to determine whether there is evidence of gender-specific decision making for transplant assessments, and how gender effects outcomes.

METHODS

Retrospective analysis of adult heart transplant assessments at a single UK centre between April 2015 and March 2020.

RESULTS

Females were 32% of referrals (N = 137 females, 285 males), with marked differences between diagnoses - 11% ischaemics and 43% of adult congenital. Females were younger, shorter, weighed less, and had lower pulmonary pressures. Females were much less likely to receive a ventricular assist device (13%). Blood type 'O' females were relatively more likely compared to males to receive a transplant (45%). Comparing males and females who received a ventricular assist device, both had similar levels of high pulmonary pressures, indicating consistent decision making based on haemodynamics to implant a device. Overall survival was better for females (in non congenital patients), and this was due to female patients who were not accepted for transplant or a ventricular assist device being more often 'too well for transplant', rather than in males when they were more often 'unsuitable'.

CONCLUSIONS

Marked gender differences exist at all stages of the heart transplant assessment pathway. Appropriate decision making based on clinical grounds is shown with less transplants in male blood type 'O's and haemodynamic criteria for ventricular assist device implantation in both genders. Further studies are need to determine if there is a wider community bias in advanced heart failure treatments for females. This article is protected by copyright. All rights reserved.

Evolving Characteristics of Heart Transplantation Donors and Recipients: JACC Focus Seminar

Although the burden of end-stage heart failure continues to increase, the number of available organs for heart transplantation (HT) remains inadequate. The HT community has been challenged to find ways to expand the number of donor hearts available. Recent advances include use of hearts from donors infected with hepatitis C virus as well as other previously underutilized donors, including those with left ventricular dysfunction, of older age, and with a history of cocaine use. Concurrently, emerging trends in HT surgery include donation after circulatory death, ex vivo normothermic heart perfusion, and controlled hypothermic preservation, which may enable procurement of organs from farther distances and prevent early allograft dysfunction. Contemporary HT recipients have also evolved in light of the 2018 revision to the U.S. heart allocation policy. This focus seminar discusses recent trends in donor and recipient phenotypes and management strategies for successful HT, as well as evolving areas and future directions.

Effector immune cells in Chronic Lung Allograft Dysfunction: a Systematic Review

Chronic lung allograft dysfunction (CLAD) remains the major barrier to long‐term survival after lung transplantation and improved insight into its underlying immunological mechanisms is critical to better understand the disease and to identify treatment targets. We systematically searched the electronic databases of PubMed and EMBASE for original research publications, published between January 2000 and April 2021, to comprehensively assess current evidence on effector immune cells in lung tissue and bronchoalveolar lavage fluid from lung transplant recipients with CLAD. Literature search revealed 1351 articles, 76 of which met the criteria for inclusion in our analysis. Our results illustrate significant complexity in both innate and adaptive immune cell responses in CLAD, along with presence of numerous immune cell products, including cytokines, chemokines and proteases associated with tissue remodelling. A clear link between neutrophils and eosinophils and CLAD incidence has been seen, in which eosinophils more specifically predisposed to restrictive allograft syndrome. The presence of cytotoxic and T‐helper cells in CLAD pathogenesis is well‐documented, although it is challenging to draw conclusions about their role in tissue processes from predominantly bronchoalveolar lavage data. In restrictive allograft syndrome, a more prominent humoral immune involvement with increased B cells, immunoglobulins and complement deposition is seen. Our evaluation of published studies over the last 20 years summarizes the complex multifactorial immunopathology of CLAD onset and progression. It highlights the phenotype of several key effector immune cells involved in CLAD pathogenesis, as well as the paucity of single cell resolution spatial studies in lung tissue from patients with CLAD.

Treatment of advanced heart failure

Background: The development of medical and device treatment of heart failure (HF) has improved the survival and quality of life in HF patients. However, not all HF patients respond well to these up-to-date HF treatments. We have termed these non-responders as advanced HF patients. The definition, diagnosis, and treatment of advanced HF are discussed in this review article.Current Concepts: After current guideline-directed treatments, advanced HF patients can experience aggravation and decompensation, usually resulting in hospitalization for the symptoms and volume control. Recurrent decompensation or hospitalization can cause a vicious cycle between the heart and other vital organs, such as the kidney and liver. Current and up-to-date guidelines recommend treatments, including heart transplant, left ventricular assist device (LVAD), and hospice care, for advanced HF. Given the limitation of heart transplant donors, LVAD can be used as a bridge to transplant, in addition to destination therapy. Updated LVAD system can reduce pump-related thrombosis, stroke, and bleeding.Discussion and Conclusion: Current guidelines suggest early recognition of advanced HF and referral to advanced HF specialists. Despite advances in the treatments of advanced HF, unmet needs for further improving clinical outcomes and quality of life exist.

The Role of Echocardiography in the Management of Heart Transplant Recipients

Transthoracic echocardiography is the primary non-invasive modality for the investigation of heart transplant recipients. It is a versatile tool that provides comprehensive information on cardiac structure and function. Echocardiography is also helpful in diagnosing primary graft dysfunction and evaluating the effectiveness of therapeutic approaches for this condition. In acute rejection, echocardiography is useful with suspected cellular or antibody-mediated rejection, with findings confirmed and quantified by endomyocardial biopsy. For identifying chronic rejection, ultrasound has a more significant role and, in some specific patients (e.g., patients with renal failure), it may offer a role comparable to coronary angiography to identify cardiac allograft vasculopathy. This review highlights the usefulness of echocardiography in evaluating normal graft function and its role in the management of heart transplant recipients.

[Epidemiological characteristics of heart transplant recipients in Peru 2010-2020]

Objective

To evaluate the epidemiological, clinical, surgical, pathological characteristics and outcomes in the follow-up of heart transplant recipients at the National Cardiovascular Institute during 2010-2020.

Material and Methods

A retrospective descriptive study was performed by reviewing the medical records of patients undergoing heart transplantation at a national referral center, describing the clinical, surgical, laboratory, pathology characteristics and survival of patients up to 10 years of follow-up.

Results

Eighty-six patients were transplanted in 10 years, the median age was 41 years (RIQ 28-56), being predominantly male (66.3%). The three leading causes of indication for heart transplantation were: dilated cardiomyopathy (48.9%), ischemic heart disease (17.4%), and myocarditis (6.9%). Total ischemia time was 160 minutes (RIQ 129.7-233.5). Survival at one, five, and ten years was 84.8%, 73.6%, and 65.7% respectively. The main cause of death was non-cardiac: infectious (39.1%) and of unknown origin (26%).

Conclusions

The main etiology of heart failure in heart transplant recipients in Peru in recent years was nonischemic dilated cardiomyopathy. We observed that the survival rate was similar to that of international registries; however, the rate of mortality due to infectious causes and death of unknown origin is high, which poses a challenge in the management of post-transplant patients.

The International Thoracic Organ Transplant Registry of the International Society for Heart and Lung Transplantation: Thirty-eighth adult lung transplantation report - 2021; Focus on recipient characteristics

For over 30 years, the International Society for Heart and Lung Transplantation (ISHLT) International Thoracic Organ Transplant (TTX) Registry has gathered data regarding transplant procedures, donor and recipient characteristics, and outcomes from a global community of transplant centers. Almost 70,000 adult lung transplant procedures have been reported to the Registry since its inception, each one providing an opportunity for a recipient with end-stage lung disease to regain quality of life and longevity. With each year's report, we provide more detailed analyses on a particular focus theme important to recipient outcomes. Since 2013, these have been donor and recipient age; retransplantation; early graft failure; indication for transplant; allograft ischemic time; multiorgan transplantation; and donor and recipient size matching.^1-7 In response to a changing regulatory environment, the ISHLT TTX Registry is undergoing an update in data acquisition, and the patient cohort examined in this report is therefore derived from the same data source or datasets as that examined in the 2019 annual reports.^2,8-10 We refer the reader to the 2019 and prior reports for a detailed description of the baseline characteristics of the cohort, and additional core analyses not directly related to the focus explored in this year's report. To complement the 2020 report which focussed on donor characteristics, the goal of this year's report was to focus entirely on changes in recipient factors over the past 3 decades and to identify important recipient characteristics and transplant processes that may influence post-transplant outcomes. Due to small numbers, heart-lung transplant recipient characteristics and transplant outcomes have not been included. This 38th annual adult lung transplant report is hence based on data submitted to the ISHLT TTX Registry on 67,493 adult recipients of deceased recipient transplants between January 1, 1992 and June 30, 2018.