Heart retransplantation

Heart Retransplantation Under the 2018 Adult Heart Allocation Policy

BACKGROUND

The purpose of the present study was to characterize the impact of the 2018 adult heart allocation policy change on waiting list and posttransplant outcomes of heart retransplantation in the United States.

METHODS

All adults listed for heart retransplantation from May 2015 to June 2022 were identified using the United Network for Organ Sharing database. Patients were stratified into eras (era 1 and era 2) based on the heart allocation change on October 18, 2018. Competing risks regressions and Cox proportional hazards models were used to assess differences across eras in waiting list outcomes and 1-year posttransplant survival, respectively.

RESULTS

The analysis included 356 repeat heart transplant recipients, with 207 (58%) receiving retransplantation during era 2. Patients who received a retransplant in era 2 were more commonly bridged with extracorporeal membrane oxygenation (21% vs 8%, P < .01) and intra-aortic balloon pump (29% vs 13%, P < .001) and had a lower likelihood of death/deterioration on the waiting list (subdistribution hazard ratio, 0.52; 95% CI, 0.33-0.82) compared with those in era 1. Rates of 30-day mortality (7% vs 7%, P = .99) and 1-year survival (82% vs 87%, P = .27) were not significantly different among retransplantation recipients across eras. After adjustment, retransplantation in era 2 was not associated with an increased hazard of mortality (adjusted hazard ratio, 1.13; 95% CI, 0.55-2.30). The gap in 1-year mortality between primary transplant and retransplant recipients increased from era 1 to 2.

CONCLUSIONS

Heart retransplantation candidates have experienced improved waiting list outcomes after the 2018 adult heart allocation policy, without significant changes to posttransplant survival.

A change of heart: Characteristics and outcomes of multiple cardiac retransplant recipients

BACKGROUND

Among heart transplant (HT) recipients who develop advanced graft dysfunction, cardiac re-transplantation may be considered. A smaller subset of patients will experience failure of their second allograft and undergo repeat re-transplantation. Outcomes among these individuals are not well-described.

METHODS

Adult and pediatric patients in the United Network for Organ Sharing (UNOS) registry who received HT between January 1, 1990 and December 31, 2020 were included.

RESULTS

Between 1990 and 2020, 90 individuals received a third HT and three underwent a fourth HT. Recipients were younger than those undergoing primary HT (mean age 32 years). Third HT was associated with significantly higher unadjusted rates of 1-year mortality (18% for third HT vs. 13% for second HT vs. 9% for primary HT, p < .001) and 10-year mortality (59% for third HT vs. 42% for second HT vs. 37% for primary HT, p < .001). Mortality was highest amongst recipients aged >60 years and those re-transplanted for acute graft failure. Long-term rates of CAV, rejection, chronic dialysis, and hospitalization for infection were also higher.

CONCLUSIONS

Third HT is associated with higher morbidity and mortality than primary HT. Further consensus is needed regarding appropriate organ stewardship for this unique subgroup.

Thoracic retransplantation: Does time to retransplantation matter?

OBJECTIVE

For some individuals, chronic allograft failure is best treated with retransplantation. We sought to determine if time to retransplantation impacts short- and long-term outcomes for heart or lung retransplant recipients with a time to retransplantation more than 1 year.

METHODS

The United Network for Organ Sharing/Organ Procurement and Transplantation Network STAR file was queried for all adult, first-time heart (June 1, 2006, to September 30, 2020) and lung (May 1, 2005, to September 30, 2020) retransplantations with a time to retransplantation of at least 1 year. Patients were grouped according to the tertile of time to retransplantation (tertile 1: 1-7.7 years, tertile 2: 7.7-14.7 years, tertile 3: 14.7+ years; lung: tertile 1: 1-2.8 years, tertile 2: 2.8-5.6 years, tertile 3: 5.6+ years). The primary outcome was survival after retransplantation. Comparative statistics identified differences in groups, and Kaplan-Meier methods and a Cox proportional hazard model were used for survival analysis.

RESULTS

After selection, 908 heart and 871 lung retransplants were identified. Among heart retransplant recipients, tertile 1 was associated with male sex, smoking history, higher listing status, and increased mechanical support pretransplant. Tertile 3 had the highest rate of concomitant kidney transplant; however, the incidence of morbidity and in-hospital mortality was similar among the groups. Unadjusted and adjusted analyses revealed no survival difference among all groups. Regarding lung retransplant recipients, tertile 1 was associated with increased lung allocation score, pretransplant hospitalization, and mechanical support. Unadjusted and adjusted survival analyses revealed decreased survival in tertile 1.

CONCLUSIONS

Time to retransplant does not appear to affect heart recipients with a time to retransplantation of more than 1 year; however, shorter time to retransplantation for prior lung recipients is associated with decreased survival. Potential lung retransplant candidates with a time to retransplantation of less than 2.8 years should be carefully evaluated before retransplantation.

Evaluating age-based eligibility thresholds for heart re-transplantation - an analysis of the united network for organ sharing database

BACKGROUND

Risk-adjusted survival after late heart re-transplantation may be comparable to primary transplant, but the efficacy of re-transplantation in older candidates is not established. We evaluated outcomes after heart re-transplantation in recipients > 60 years.

METHODS

We identified 1026 adult patients undergoing isolated heart re-transplantation between 2003 and 2020 from the United Network for Organ Sharing database. Older recipients (> 60 years, n=177) were compared to younger recipients (≤ 60 years, n=849). Five and ten-year post-transplant survival was estimated using the Kalpan-Meier method and adjusted with multivariable Cox models.

RESULTS

Older recipients were more likely to be male and have diabetes or previous malignancies with higher baseline creatinine. They also more frequently required pre-transplant ECMO (11.9% vs. 6.8%, p=0.02) and received re-transplantation due to primary graft failure (13.6% vs. 8.5%, p=0.03). After the transplant, older recipients had a higher incidence of stroke (6.8% vs. 2.6%, p=0.01) and dialysis requirements (20.3% vs. 13.2%) before discharge (both p<0.05), and more frequently died from malignancy-related causes (16.3% vs. 3.9%, p<0.001). After adjustment, recipient age >60 was associated with an increased risk of both 5-year (HR 1.42, 95% CI 1.02-2.01, p=0.04) and 10-year mortality (HR 1.72, 95% CI 1.20-2.45, p=0.003). Restricted cubic spline showed a non-linear relationship between recipient age and 10-year mortality.

CONCLUSIONS

Heart re-transplantation in recipients > 60 years has inferior outcomes compared to younger recipients. Strict patient selection and close follow-up are warranted to ensure the appropriate utilization of donor hearts and to improve long-term outcomes.

Predictors of one-year outcome after cardiac re-transplantation: Machine learning analysis

BACKGROUND

As cardiac re-transplantation is associated with inferior outcomes compared with primary transplantation, allocating scarce resources to appropriate re-transplant candidates is important. The aim of this study is to elucidate the factors associated with 1-year mortality in cardiac re-transplantation using the random forests algorithm for survival analysis.

METHODS

We retrospectively reviewed the United Network for Organ Sharing registry and identified all adult (>17 years old) recipients who underwent cardiac re-transplantation between January 2000 and March 2020. The random forest algorithm on Cox modeling was used to calculate the variable importance (VIMP) of independent variables for contributing to one-year mortality.

RESULTS

A total of 1294 patients underwent cardiac re-transplantation. Of these, 137 patients were re-transplanted within one year of their first transplant, while 1157 patients were re-transplanted more than one year after their first transplant. One-year mortality was significantly higher for patients receiving early transplantation compared with those receiving late transplantation (Early 40.6% vs. Late 13.6%, log-rank P<0.001). Machine learning analysis showed that total bilirubin (>2 mg/dl) (VIMP, 2.99%) was an independent predictor of one-year mortality after early re-transplant. High BMI (>30.0 kg/m2) (VIMP, 1.43%) and ventilator dependence (VIMP, 1.47%) were independent predictors of one-year mortality for the late re-transplantation group.

CONCLUSION

Machine learning showed that optimal one-year survival following cardiac re-transplantation was significantly related to liver function in early re-transplantation, and to obesity and preoperative ventilator dependence in late re-transplantation. This article is protected by copyright. All rights reserved.

Heart transplantation: focus on donor recovery strategies, left ventricular assist devices, and novel therapies

Heart transplantation is advocated in selected patients with advanced heart failure in the absence of contraindications. Principal challenges in heart transplantation centre around an insufficient and underutilized donor organ pool, the need to individualize titration of immunosuppressive therapy, and to minimize late complications such as cardiac allograft vasculopathy, malignancy, and renal dysfunction. Advances have served to increase the organ donor pool by advocating the use of donors with underlying hepatitis C virus infection and by expanding the donor source to use hearts donated after circulatory death. New techniques to preserve the donor heart over prolonged ischaemic times, and enabling longer transport times in a safe manner, have been introduced. Mechanical circulatory support as a bridge to transplantation has allowed patients with advanced heart failure to avoid progressive deterioration in hepato-renal function while awaiting an optimal donor organ match. The management of the heart transplantation recipient remains a challenge despite advances in immunosuppression, which provide early gains in rejection avoidance but are associated with infections and late-outcome challenges. In this article, we review contemporary advances and challenges in this field to focus on donor recovery strategies, left ventricular assist devices, and immunosuppressive monitoring therapies with the potential to enhance outcomes. We also describe opportunities for future discovery to include a renewed focus on long-term survival, which continues to be an area that is under-studied and poorly characterized, non-human sources of organs for transplantation including xenotransplantation as well as chimeric transplantation, and technology competitive to human heart transplantation, such as tissue engineering.

Results of heart retransplantation: subanalysis of the Spanish Heart Transplant Registry

INTRODUCTION AND OBJECTIVES

Heart retransplantation (ReHT) is controversial in the current era. The aim of this study was to describe and analyze the results of ReHT in Spain.

METHODS

We performed a retrospective cohort analysis from the Spanish Heart Transplant Registry from 1984 to 2018. Data were collected on donors, recipients, surgical procedure characteristics, immunosuppression, and survival. The main outcome was posttransplant all-cause mortality or need for ReHT. We studied differences in survival according to indication for ReHT, the time interval between transplants and era of ReHT.

RESULTS

A total of 7592 heart transplants (HT) and 173 (2.3%) ReHT were studied (median age, 52.0 and 55.0 years, respectively). Cardiac allograft vasculopathy was the most frequent indication for ReHT (42.2%) and 59 patients (80.8%) received ReHT >5 years after the initial transplant. Acute rejection and primary graft failure decreased as indications over the study period. Renal dysfunction, hypertension, need for mechanical ventilation or intra-aortic balloon pump and longer cold ischemia time were more frequent in ReHT. Median follow-up for ReHT was 5.8 years. ReHT had worse survival than HT (weighted HR, 1.43; 95%CI, 1.17-1.44; P<.001). The indication of acute rejection (HR, 2.49; 95%CI, 1.45-4.27; P<.001) was related to the worst outcome. ReHT beyond 5 years after initial HT portended similar results as primary HT (weighted HR, 1.14; 95%CI, 0.86-1.50; P<.001).

CONCLUSIONS

ReHT was associated with higher mortality than HT, especially when indicated for acute rejection. ReHT beyond 5 years had a similar prognosis to primary HT.

miR-21 antagonism reprograms macrophage metabolism and abrogates chronic allograft vasculopathy

Despite much progress in improving graft outcome during cardiac transplantation, chronic allograft vasculopathy (CAV) remains an impediment to long-term graft survival. MicroRNAs (miRNAs) emerged as regulators of the immune response. Here, we aimed to examine the miRNA network involved in CAV. miRNA profiling of heart samples obtained from a murine model of CAV and from cardiac-transplanted patients with CAV demonstrated that miR-21 was most significantly expressed and was primarily localized to macrophages. Interestingly, macrophage depletion with clodronate did not significantly prolong allograft survival in mice, while conditional deletion of miR-21 in macrophages or the use of a specific miR-21 antagomir resulted in indefinite cardiac allograft survival and abrogated CAV. The immunophenotype, secretome, ability to phagocytose, migration, and antigen presentation of macrophages were unaffected by miR-21 targeting, while macrophage metabolism was reprogrammed, with a shift toward oxidative phosphorylation in naïve macrophages and with an inhibition of glycolysis in pro-inflammatory macrophages. The aforementioned effects resulted in an increase in M2-like macrophages, which could be reverted by the addition of L-arginine. RNA-seq analysis confirmed alterations in arginase-associated pathways associated with miR-21 antagonism. In conclusion, miR-21 is overexpressed in murine and human CAV, and its targeting delays CAV onset by reprogramming macrophages metabolism.

Nuclear Osteopontin Is a Marker of Advanced Heart Failure and Cardiac Allograft Vasculopathy: Evidence From Transplant and Retransplant Hearts

Background

Heart transplant is the gold standard therapy for patients with advanced heart failure. Over 5,500 heart transplants are performed every year worldwide. Cardiac allograft vasculopathy (CAV) is a common complication post-heart transplant which reduces survival and often necessitates heart retransplantation. Post-transplant follow-up requires serial coronary angiography and endomyocardial biopsy (EMB) for CAV and allograft rejection screening, respectively; both of which are invasive procedures. This study aims to determine whether osteopontin (OPN) protein, a fibrosis marker often present in chronic heart disease, represents a novel biomarker for CAV.

Methods

Expression of OPN was analyzed in cardiac tissue obtained from patients undergoing heart retransplantation using immunofluorescence imaging (n = 20). Tissues from native explanted hearts and three serial follow-up EMB samples of transplanted hearts were also analyzed in five of these patients.

Results

Fifteen out of 20 patients undergoing retransplantation had CAV. 13/15 patients with CAV expressed nuclear OPN. 5/5 patients with multiple tissue samples expressed nuclear OPN in both 1^st and 2^nd explanted hearts, while 0/5 expressed nuclear OPN in any of the follow-up EMBs. 4/5 of these patients had an initial diagnosis of dilated cardiomyopathy (DCM).

Conclusion

Nuclear localization of OPN in cardiomyocytes of patients with CAV was evident at the time of cardiac retransplant as well as in patients with DCM at the time of the 1^st transplant. The results implicate nuclear OPN as a novel biomarker for severe CAV and DCM.

Heart Retransplantation: Candidacy, Outcomes, and Management

PURPOSE OF REVIEW

To describe the incidence and epidemiology of heart retransplantation in adults and children and to review the risk factors associated with adverse outcome following retransplantation to help guide recipient selection.

RECENT FINDINGS

Heart retransplantation is associated with inferior short-term and long-term survival when compared with primary heart transplantation and its use remains controversial although less so in the pediatric heart transplant population.

SUMMARY

In the most recent era of heart transplantation, patients retransplanted for CAV, greater than 1 year from their primary transplant, and who are not in critical condition have improved survival compared with other retransplant recipients. Survival with retransplantation can approach that of primary transplantation when patients are appropriately selected. More research is needed regarding the optimal timing for retransplantation and the optimal management for patients after retransplantation.

Outcomes and survival following heart retransplantation for cardiac allograft failure: a systematic review and meta-analysis

Background

Long-term efficacy of heart retransplantation (RTx) for end-stage cardiac allograft failure remains unclear given the limited worldwide experience and is an important question to elucidate given the shortage of donor organs. The aim of this systematic review was to examine the outcomes of RTx in patients with cardiac allograft failure.

Methods

Electronic search was performed to identify all studies in the English literature assessing RTx for cardiac allograft failure. All identified articles were systematically assessed for inclusion and exclusion criteria.

Results

Eleven studies were included for analysis, with a total of 7,791 patients. A total of 7,446 patients underwent primary heart transplantation (HTx) whereas 345 patients underwent RTx with average time from primary HTx to RTx interval of 5.03 years (95% CI: 3.13-6.94 years). There were 35.2% of patients received RTx within 30 days of primary transplant. Early mortality was significantly higher among RTx patients (RTx 28.2% vs. HTx 11.2%, P<0.001) whereas survival was significantly higher among HTx patients when compared to RTx patients at 1 year (HTx 81.8% vs. RTx 59.1%, P<0.001), 2 years (HTx 77.9% vs. RTx 53.6%, P<0.001), 3 years (HTx 76.1% vs. RTx 49.8%, P<0.001), 5 years (HTx 68.8% vs. RTx 41.4%, P<0.001) and 10 years (HTx 53.9% vs. RTx 31.7%, P<0.001). There were no significant differences between HTx and RTx in terms of freedom from rejection at 1 year (HTx 61.0% vs. RTx 53.7%, P=0.43), 2 years (HTx 63.8% vs. RTx 53.7%, P=0.26), 3 years (HTx 62.9% vs. RTx 51.9%, P=0.30) and 5 years (HTx 61.0% vs. RTx 51.9%, P=0.36).

Conclusions

Patients who underwent heart RTx had a significant lower survival when compared to those who only underwent primary HTx. There were no significant differences in post-transplantation freedom from rejection. Careful patient selection and perioperative care can make heart RTx a viable option for selected recipients.

Inhibition of C-X-C motif chemokine 10 reduces graft loss mediated by memory CD8+ T cells in a rat cardiac re-transplant model

The interaction of chemokine (C-X-C motif) ligand 10 (CXCL10) with its receptor (CXCR3) is a critical process in recruiting donor reactive T cells to a graft and alloantigen-specific memory T (Tm) cells exert a principal function in promoting graft dysfunction during accelerated cardiac rejection. However, whether CXCL10 chemokine exerts any effects on acute accelerated rejection mediated by CD8⁺ Tm cells in a re-transplant model has remained elusive. The present study established a cardiac transplant model by advanced microsurgery technology and improved organ storage. A novel rat model of cardiac re-transplantation was established at 40 days following primary heart transplant. The experiment included two parts, and when models were established, the rats were divided into two groups: Primary cardiac transplant (HTx) and re-transplantation without treatment (HRTx). In part 1, recipients from part 2, including re-transplantation without treatment (HRTx+NS) and re-transplantation treated with anti-CXCL10 antibodies (500 µg every other day by intraperitoneal injection; HRTx+CXCL10 Abs group). The graft survival time was observed and graft infiltration by inflammatory cells was assessed via histology of cardiac graft sections; in addition, the gene expression and the serum concentration of CXCL10 in each group was assessed. Indexes such as rejection-associated cytokines were assayed by reverse-transcription quantitative PCR and ELISA kits, and flow cytometry of splenocytes was used to detect Tm cells in the re-transplantation groups. The results demonstrated that level of CXCL10 was significantly increased and the graft mean survival time was shortened accompanied with aggravated lymphocyte cell infiltration in the HRTx group when compared that in the HTx group; in addition, the serum levels and mRNA expression of interleukin (IL)-2 and interferon (IFN)-γ were increased, while transforming growth factor (TGF)-β was decreased in the HRTx group. Furthermore, neutralization of CXCL10 prolonged the graft mean survival time and delayed accelerated rejection. Compared with that in the HRTx+NS group, serum levels and graft tissue mRNA expression of IFN-γ and IL-2 were decreased in the HRTx+CXCL10 Abs group, while TGF-β mRNA was significantly increased but the serum concentration was not significantly affected. In addition, there was no difference in IL-10 between the two groups, while delayed accelerated rejection paralleled with inflammatory cell infiltration decreased and the proliferation and differentiation of CD8⁺ Tm cells in secondary lymphoid organs were reduced in the HRTx+CXCL10 Abs group vs. those in the HRTx+NS group. The present study demonstrated that CXCL10 had a crucial role in cardiac transplantation and re-transplantation, and that treatment with CXCL10 antibodies delays accelerated acute rejection mediated by Tm cells in a rat model of cardiac re-transplantation.

Thalidomide treatment prevents chronic graft rejection after aortic transplantation in rats - an experimental study

Cardiac allograft vasculopathy (CAV) affects approximately 30% of cardiac transplant patients at 5 years post-transplantation. To date, there are few CAV treatment or prevention options, none of which are highly effective. The aim of the study was to investigate the effect of thalidomide on the development of CAV. The effect of thalidomide treatment on chronic rejection was assessed in rat orthotopic aortic transplants in allogeneic F344 or syngeneic Lew rats (n = 6 per group). Animals were left untreated or received thalidomide for 30 days post-transplant, and evidence of graft CAV was determined by histology (trichrome and immunohistochemistry) and intragraft cytokine measurements. Animals that received thalidomide treatment post-transplant showed markedly reduced luminal obliteration, with concomitant rescue of smooth muscle cells (SMCs) in the aortic media of grafts. Thalidomide counteracted neointimal hyperplasia by preventing dedifferentiation of vascular SMCs. Measurement of intragraft cytokine levels after thalidomide treatment revealed downregulation of matrix metalloproteinase 8 and monocyte chemotactic protein 1, cytokines involved in tissue remodelling and inflammation, respectively. Importantly, no negative side effects of thalidomide were observed. Thalidomide treatment prevents CAV development in a rodent model and is therefore potentially useful in clinical applications to prevent post-transplant heart rejection.

Retransplant and Medical Therapy for Cardiac Allograft Vasculopathy: International Society for Heart and Lung Transplantation Registry Analysis

Cardiac retransplantation for heart transplant recipients with advanced cardiac allograft vasculopathy (CAV) remains controversial. The International Society for Heart and Lung Transplantation Registry was used to examine survival in adult heart recipients with CAV who were retransplanted (ReTx) or managed medically (MM). Recipients transplanted between 1995 and 2010 who developed CAV and were either retransplanted within 2 years of CAV diagnosis (ReTx) or alive at ≥2 years after CAV diagnosis, managed medically (MM), without retransplant, constituted the study groups. Donor, recipient, transplant characteristics and long-term survival were compared. The population included 65 patients in ReTx and 4530 in MM. During a median follow-up of 4 years, there were 24 deaths in ReTx, and 1466 in MM. Survival was comparable at 9 years (55% in ReTx and 51% in MM; p = 0.88). Subgroup comparison suggested survival benefit for retransplant versus MM in patients who developed systolic graft dysfunction. Adjusted predictors for 2-year mortality were diagnosis of CAV in the early era and longer time since CAV diagnosis following primary transplant. Retransplant was not an independent predictor in the model. Challenges associated with retransplantation as well as improved CAV treatment options support the current consensus recommendation limiting retransplant to highly selected patients with CAV.

Heart Retransplant Recipients Have Better Survival With Concurrent Kidney Transplant Than With Heart Retransplant Alone

BACKGROUND

Heart retransplant (HRT) recipients represent a growing number of transplant patients. The impact of concurrent kidney transplants (KTs) in this population has not been well studied. We tested the hypothesis that recipients of HRT with concurrent KT (HRT-KT) would have worse survival than recipients of HRT alone.

METHODS AND RESULTS

A retrospective analysis of the United Network of Organ Sharing database was performed for all patients undergoing HRT from 1987 to 2011. There were 1660 HRT patients, of which 116 (7%) received concurrent KT. Those who received HRT-KT had older age, longer wait-list time, worse kidney function, and more known diabetes. Survival among recipients of HRT-KT was significantly better than that of recipients of HRT alone (P=0.005). A subgroup of 323 HRT patients with severe kidney dysfunction (estimated glomerular filtration rate <30 mL/min per 1.73 m(2) or on dialysis) was studied in more detail, and 76 (24%) received concurrent KT. Those on dialysis at the time of HRT had better survival with versus without concurrent KT (P<0.0001). On multivariable analysis, concurrent KT was independently associated with better outcomes for all patients with HRT and for the subgroup of patients with severe kidney dysfunction.

CONCLUSIONS

Recipients of HRT-KT have better survival than recipients of HRT alone. Further research is needed to determine which HRT patients may benefit the most from concurrent KT.

Pediatric cardiac retransplantation: Waitlist mortality stratified by age and era

BACKGROUND

Waitlist mortality among children listed for primary heart transplant (HTx) has been well characterized, whereas limited data exist for cardiac retransplantation (CRTx) after pediatric primary HTx. We sought to characterize the population listed for CRTx and to determine the factors that affect waitlist mortality.

METHODS

All individuals listed for CRTx >1 year after pediatric primary HTx between October 1, 1987, and October 14, 2012 were identified in the Organ Procurement and Transplantation Network database. Baseline characteristics and waitlist mortality were compared between age groups (< 11 years, 11-18 years, and > 18 years) and during 3 successive eras (1987-1999, 1999-2006, and 2006-2012).

RESULTS

The cohort comprised 632 patients who were listed for CRTx > 1 year after pediatric primary HTx. Median age was 4 years at primary HTx and 14 years at relisting. Median time from primary HTx to relisting was 7.3 years. Median waiting time was 75.3 days. Overall mortality was 25.2% (159 of 632). The most frequent relisting diagnosis was related to graft vasculopathy (62.5%). The leading causes of death were chronic rejection and vasculopathy (52%). Waitlist mortality significantly decreased after 2006 (31% vs 17%; p < 0.01), despite a relatively constant CRTx rate (67% vs 65%). Univariate analysis showed era, age, listing status, and life support (mechanical circulatory support device, extracorporeal membrane oxygenation, mechanical ventilation) were significant predictors of mortality. Multivariate analyses showed that later era (2006-2012), ages 11 to 18 years, and United Network of Organ Sharing listing status 2 predicted decreased mortality, whereas life support increased mortality.

CONCLUSIONS

Waitlist mortality for CRTx in children and young adults has decreased by almost 50% over time. Individuals relisted as adults have increased waitlist mortality.

CXCL9 and CXCL10 accelerate acute transplant rejection mediated by alloreactive memory T cells in a mouse retransplantation model

C-X-C motif chemokine ligand (CXCL) 9 and CXCL10 play key roles in the initiation and development of acute transplant rejection. Previously, higher levels of RANTES expression and secretion were demonstrated in retransplantation or T-cell memory-transfer models. In the present study, the effect of the chemokines, CXCL9 and CXCL10, were investigated in a mouse retransplantation model. BALB/c mice were used as donors, while C57BL/6 mice were used as recipients. In the experimental groups, a heterotopic heart transplantation was performed six weeks following skin grafting. In the control groups, a heterotopic heart transplantation was performed without skin grafting. Untreated mice served as blank controls. The mean graft survival time of the heterotopic heart transplantations was 7.7 days in the experimental group (n=6), as compared with 3.25 days in the control group (n=6; P<0.001). On day three following cardiac transplantation, histological evaluation of the grafts revealed a higher International Society for Heart & Lung Transplantation grade in the experimental group as compared with the control group. In addition, gene expression and serum concentrations of CXCL9, CXCL10, interferon-γ, and interleukin-2 were markedly higher in the experimental group when compared with the control group. Differences between the levels of CXCL9 and CXCL10 in the pre- and post-transplant mice indicated that the chemokines may serve as possible biomarkers to predict acute rejection. The results of the present study demonstrated that CXCL9 and CXCL10 play a critical role in transplantation and retransplantation. High levels of these cytokines during the pre-transplant period may lead to extensive acute rejection. Thus, the observations enhance the understanding of the mechanism underlying the increased expression and secretion of CXCL9 and CXCL10 by alloreactive memory T cells.

Preoperative risk factors predict survival following cardiac retransplantation: analysis of the United Network for Organ Sharing database

BACKGROUND

The aim of our study was to identify preoperative risk factors affecting overall survival after cardiac retransplantation (ReTX) in a contemporary era.

METHODS

The United Network for Organ Sharing database was used to identify patients undergoing ReTX between 1995 and 2012. Of the total 28,464 primary transplants performed, 987 (3.5%) were retransplants. The primary outcome investigated was overall survival. The influence of preoperative donor and recipient characteristics on survival were then tested with univariate logistic regression and multivariate Cox regression models.

RESULTS

Of 987 patients who underwent ReTX, median survival was 9 years. Estimated survival at 1, 3, 5, 10, and 15 years following retransplant was 80% (95% confidence interval [CI], 78%-83%), 70% (95% CI, 67%-73%), 64% (95% CI, 61%-67%), 47% (95% CI, 43%-51%), and 30% (95% CI, 25%-37%), respectively. Clinical predictors of survival using multivariable analysis included donor age (relative risk [RR], 1.14; P = .004), ischemic time > 4 hours (RR, 1.48; P = .004); preoperative support with extracorporeal membrane oxygenator (RR, 3.91; P < .001), and the time between previous and current transplant (P = .004). Patients with ReTX have 1.27 times higher relative risk of death compared with patients undergoing primary transplant only (RR, 1.27; 95% CI, 1.13-1.42; P < .001).

CONCLUSIONS

Patients who undergo cardiac ReTX can expect to have a 1-year survival less than a patient undergoing primary transplant with an acceptable median overall survival. Both donor and recipient preoperative factors contribute to overall survival following cardiac ReTx. Donor characteristics include age of the donor and ischemic time. Recipient factors include the need for extracorporeal membrane oxygenator and the number of days between the first and second transplant. Optimal survival following cardiac ReTX can best be predicted by choosing patients who are farther out from their initial transplant, not dependent upon preoperative extracorporeal support, and by choosing donor hearts younger in age and those likely to have shorter ischemic times.

A review of cardiac transplantation

Perioperative anesthetic management for cardiac transplantation is reviewed. Recent developments in adult cardiac transplantation are noted. This review includes demographics and historical results, recipient and donor selection and evaluation, mechanical circulatory support and heart transplantation techniques, and patient management immediately postimplantation.

Prevention and treatment of coronary artery vasculopathy

PURPOSE OF REVIEW

Cardiac allograft vasculopathy (CAV) is still one of the major causes of death following heart transplantation. Here, we review the recent advances in its prevention and treatment.

RECENT FINDINGS

Preventive measures comprise control of classical risk factors, prophylaxis against cytomegalovirus, avoidance of graft endothelial damage during heart transplantation, and prevention of acute rejection. These measures can be effective if begun early. The treatment options for established CAV are limited, percutaneous revascularization and coronary artery bypass graft only being viable for a minority of patients because of the diffuse nature of CAV. Retransplantation is the only definitive therapy for CAV and may be considered for suitable patients with advanced CAV and allograft dysfunction. One of the most promising developments in the recent years is the use of mTOR inhibitors, which can now be regarded as effective in preventing CAV in de novo patients; their role in the treatment of established CAV is still uncertain despite some encouraging recent findings.

SUMMARY

The implementation of measures and lifestyles that help prevent CAV should be a priority of postheart transplantation management. Research should urgently evaluate mTOR inhibitors for the treatment of established CAV.

[Diagnosis, prevention and treatment of cardiac allograft vasculopathy]

The major limitation of long-term survival after cardiac transplantation is allograft vasculopathy, which consists of concentric and diffuse intimal hyperplasia. The disease still has a significant incidence, estimated at 30% five years after cardiac transplantation. It is a clinically silent disease and so diagnosis is a challenge. Coronary angiography supplemented by intravascular ultrasound is the most sensitive diagnostic method. However, new non-invasive diagnostic techniques are likely to be clinically relevant in the future. The earliest possible diagnosis is essential to prevent progression of the disease and to improve its prognosis. A new nomenclature for allograft vasculopathy has been published in July 2010, developed by the International Society for Heart and Lung Transplantation (ISHLT), establishing a standardized definition. Simultaneously, the ISHLT published new guidelines standardizing the diagnosis and management of cardiac transplant patients. This paper reviews contemporary concepts in the pathophysiology, diagnosis, prevention and treatment of allograft vasculopathy, highlighting areas that are the subject of ongoing research.

Heart retransplantation for pediatric primary allograft failure

PURPOSE

Heart transplantation is indicated for children with end-stage heart failure or complex inoperable congenital defects. When the transplanted heart fails, retransplantation is suggested and herein we have presented the prognosis of these pediatric cases.

MATERIALS AND METHODS

From March 1987 to March 2011, we performed 404 heart transplantations including 45 pediatric patients, 6 (13.3%) of whom experienced graft failure requiring retransplantation. Only four of the six patients (66.7%) had a chance for retransplantation.

RESULTS

Six of 45 pediatric heart transplant patients (13.3%) experienced graft failure requiring retransplantation. Four of them (66.7%) underwent retransplantation. Only one of the four died due to severe postoperative sepsis with acute respiratory distress. The other three patients recovered well and remain alive with no neurological sequelae; all are in New York Heart Association functional classification I at present.

CONCLUSION

Pediatric post-heart graft failure require expectations retransplantation, which shows a good prognosis.

Luminex-based virtual crossmatching facilitates combined third-time cardiac and de novo renal transplantation in a sensitized patient with sustained antibody-mediated cardiac allograft rejection

Allosensitization represents a major obstacle to successful re-transplantation since circulating antibodies can elicit antibody-mediated rejection episodes with subsequent graft failure. Since sensitization is primarily considered a contraindication to transplantation the duration for patients waiting for a suitable donor organ to become available is considerably prolonged. Herein, we report on the successful application of a Luminex-based virtual crossmatch approach to facilitate combined third-time cardiac and de novo renal transplantation in a sensitized patient with sustained antibody-mediated cardiac allograft rejection.

Pediatric cardiac retransplant: differing patterns of primary graft failure by age at first transplant

OBJECTIVE

This study compared graft failure leading to retransplant in infants versus older children at initial heart transplant.

METHODS

Twenty-six retransplant recipients were compared by age at first transplant: infant group (<1 year) and pediatric group (≥1 year).

RESULTS

Early retransplant survival was 92%. Retransplant survivals at 1, 3, and 5 years were 83%, 74%, and 67%. There were 15 infant and 11 pediatric patients. First transplant ages were 0.4 ± 0.3 vs. 8.5 ± 5.7 years in infant and pediatric groups, respectively (P < .01). First graft rejection episodes were more common in pediatric group (4.8 ± 2.5 vs 3.1 ± 2.1, P = .032), and rejection rate was higher (1.5 ± 1.1 vs 0.4 ± 0.4, P = .0024). Median first graft survival was longer in infant group (10.7 years vs 3.9 years, P < .001). Recurrent cellular rejection was retransplant indication in 40% of infant group versus 91% of pediatric group (P < .05). Cardiac allograft vasculopathy was more prevalent in infant group (73% vs 20% in pediatric group, P = .032).

CONCLUSIONS

Infant heart transplant recipients had longer primary graft survival, fewer cellular rejection episodes, and higher incidence of cardiac allograft vasculopathy relative to older graft recipients requiring retransplant. Advantages in adaptive immunity in infant heart recipients confer improved primary graft survival, but longer graft life in these patients is limited by cardiac allograft vasculopathy. Older recipient first graft failure was rejection related, and shorter graft life probably limited development of cardiac allograft vasculopathy.

Heart transplantation in the United States, 1999-2008

This article features 1999-2008 trends in heart transplantation, as seen in data from the Organ Procurement and Transplantation Network (OPTN) and the Scientific Registry of Transplant Recipients (SRTR). Despite a 32% decline in actively listed candidates over the decade, there was a 20% increase from 2007 to 2008. There continues to be an increase in listed candidates diagnosed with congenital heart disease or retransplantation. The proportion of patients listed as Status 1A and 1B continues to increase, with a decrease in Status 2 listings. Waiting list mortality decreased from 2000 through 2007, but increased 18% from 2007 to 2008; despite the increase in waiting list death rates in 2008, waiting list mortality for Status 1A and Status 1B continues to decrease. Recipient numbers have varied by 10% over the past decade, with an increased proportion of transplants performed in infants and patients above 65 years of age. Despite the increase in Status 1A and Status 1B recipients at transplant, posttransplant survival has continued to improve. With the rise in infant candidates for transplantation and their high waiting list mortality, better means of supporting infants in need of transplant and allocation of organs to infant candidates is clearly needed.

Higher rate of comorbidities after cardiac retransplantation contributes to decreased survival

BACKGROUND

Cardiac retransplantation is the definitive treatment for allograft failure despite decreased long-term survival in these patients. The cause of the poorer outcomes in cardiac retransplant patients is unclear.

METHODS

This study was a retrospective analysis of 859 adult cardiac transplant patients. Of these, 45 (5.7%) underwent cardiac retransplantation at 8.2 +/- 5.3 (mean +/- SD) years after the first transplant, primarily for severe transplant vasculopathy (n = 42).

RESULTS

One-year survival for retransplant patients was significantly lower compared with de novo transplant patients (75% vs 87%; p < 0.003). Twenty-three patients died due to either malignancy (n = 8), infection (n = 6), rejection (n = 3), sudden death (n = 2), recurrent transplant coronary artery disease (n = 2) or post-operative bleeding (n = 1).

CONCLUSION

Although cardiac retransplantation has immediate life-saving benefits, survival is lower compared with de novo cardiac transplantation due to higher rates of malignancy and infection.

Management of allosensitized cardiac transplant candidates

Cardiac transplantation remains the best treatment in patients with advanced heart failure with a high risk of death. However, an inadequate supply of donor hearts decreases the likelihood of transplantation for many patients. Ventricular assist devices (VADs) are being increasingly used as a bridge to transplantation in patients who may not survive long enough to receive a heart. This expansion in VAD use has been associated with increasing rates of allosensitization in cardiac transplant candidates. Anti-HLA antibodies can be detected before transplantation using different techniques. Complement-dependent lymphocytotoxicity assays are widely used for measurement of panel-reactive antibody (PRA) and for crossmatch purposes. Newer assays using solid-phase flow techniques feature improved specificity and offer detailed information concerning antibody specificities, which may lead to improvements in donor-recipient matching. Allosensitization prolongs the wait time for transplantation and increases the risk of post-transplantation complications and death; therefore, decreasing anti-HLA antibodies in sensitized transplant candidates is of vital importance. Plasmapheresis, intravenous immunoglobulin, and rituximab have been used to decrease the PRA before transplantation, with varying degrees of success. The most significant post-transplantation complications seen in allosensitized recipients are antibody-mediated rejection (AMR) and cardiac allograft vasculopathy (CAV). Often, AMR manifests with severe allograft dysfunction and hemodynamic compromise. The underlying pathophysiology is not fully understood but appears to involve complement-mediated activation of endothelial cells resulting in ischemic injury. The treatment of AMR in cardiac recipients is largely empirical and includes high-dose corticosteroids, plasmapheresis, intravenous immunoglobulin, and rituximab. Diffuse concentric stenosis of allograft coronary arteries due to intimal expansion is a characteristic of CAV. Its pathophysiology is unclear but may involve chronic complement-mediated endothelial injury. Sirolimus and everolimus can delay the progression of CAV. In some nonsensitized cardiac transplant recipients, the de novo formation of anti-HLA antibodies after transplantation may increase the likelihood of adverse clinical outcomes. Serial post-transplantation PRAs may be advisable in patients at high risk of de novo allosensitization.