Combined heart and liver transplant attenuates cardiac allograft vasculopathy compared with isolated heart transplantation. Transplantation. 2013;95:859-865. [PMID: 23364484 DOI: 10.1097/tp.0b013e31827eef7e]

Comparison of cardiac allograft vasculopathy incidence between simultaneous multiorgan and isolated heart transplant recipients in the United States

BACKGROUND

Prior studies have shown reduced development of cardiac allograft vasculopathy (CAV) in multiorgan transplant recipients. The aim of this study was to compare the incidence of CAV between isolated heart transplants and simultaneous multiorgan heart transplants in the contemporary era.

METHODS

We utilized the Scientific Registry of Transplant Recipients to perform a retrospective analysis of first-time adult heart transplant recipients between January 1, 2010 and December 31, 2019 in the United States. The primary end-point was the development of angiographic CAV within 5 years of follow-up.

RESULTS

Among 20,591 patients included in the analysis, 1,279 (6%) underwent multiorgan heart transplantation (70% heart-kidney, 16% heart-liver, 13% heart-lung, and 1% triple-organ), and 19,312 (94%) were isolated heart transplant recipients. The average age was 53 years, and 74% were male. There were no significant between-group differences in cold ischemic time. The incidence of acute rejection during the first year after transplant was significantly lower in the multiorgan group (18% vs 33%, p < 0.01). The 5-year incidence of CAV was 33% in the isolated heart group and 27% in the multiorgan group (p < 0.0001); differences in CAV incidence were seen as early as 1 year after transplant and persisted over time. In multivariable analysis, multiorgan heart transplant recipients had a significantly lower likelihood of CAV at 5 years (hazard ratio = 0.76, 95% confidence interval: 0.66-0.88, p < 0.01).

CONCLUSIONS

Simultaneous multiorgan heart transplantation is associated with a significantly lower long-term risk of angiographic CAV compared with isolated heart transplantation in the contemporary era.

Combined Organ Transplantation in Patients with Advanced Liver Disease

Transplantation of the liver in combination with other organs is an increasingly performed procedure. Over the years, continuous improvement in survival could be realized through careful patient selection and refined organ preservation techniques, in spite of the challenges posed by aging recipients and donors, as well as the increased use of steatotic liver grafts. Herein, we revisit the epidemiology, allocation policies in different transplant zones, indications, and outcomes with regard to simultaneous organ transplants involving the liver, that is combined heart-liver, liver-lung, liver-kidney, and multivisceral transplantation. We address challenges surrounding combined organ transplantation such as equity, utility, and logistics of dual organ implantation, but also advantages that come along with combined transplantation, thereby focusing on molecular mechanisms underlying immunoprotection provided by the liver to the other allografts. In addition, the current standing and knowledge of machine perfusion in combined organ transplantation, mostly based on center experience, will be reviewed. Notwithstanding all the technical advances, shortage of organs, and the lack of universal eligibility criteria for certain multi-organ combinations are hurdles that need to be tackled in the future.

Simultaneous combined transplantation: Intricacies in immunosuppression management

Simultaneous combined transplantation (SCT), i.e. the transplantation of two solid organs within the same procedure, can be required when the patients develop more than one end-stage organ failure. The development of SCT over the last 20 years could only be possible thanks to progress in the surgical techniques and in the perioperative management of patients in an ageing population. Performing such major transplant surgeries from the same donor, in a short amount of time, and in critical pathophysiological conditions, is often considered to be counterbalanced by the immune benefits expected from these interventions. However, SCT includes a wide array of different transplant combinations, with each time a different immunological constellation. Recent research offers new insights into the immune mechanisms involved in these different settings. Progress in the understanding of these immunological intricacies help to address the optimal induction and maintenance immunosuppressive treatment strategies. In this review, we summarize the different immunological benefits according to the type of SCT performed. We also incorporate the main outcomes according to the immunological risk at transplantation, and the deleterious impact of preformed or de novo donor-specific antibodies (DSA) in the different types of SCT. Finally, we propose comprehensive and evidence-based induction and maintenance immunosuppression strategies guided by the type of SCT.

Two is better than one: when to consider multiorgan transplant

PURPOSE OF REVIEW

Patients with end-stage heart failure often present with concomitant end-stage renal or end-stage liver disease requiring transplantation. There are limited data regarding the risks, benefits and long-term outcomes of heart-kidney (HKT) and heart-liver transplantation (HLT), and guidelines are mainly limited to expert consensus statements.

RECENT FINDINGS

The incidence of HKT and HLT has steadily increased in recent years with favourable outcomes. Both single-centre and large database studies have shown benefits of HKT/HLT through improved survival, freedom from dialysis and lower rates of rejection and coronary allograft vasculopathy. Current guidelines are institution dependent and controversial due to the ethical considerations surrounding multiorgan transplantation (MOT).

SUMMARY

MOT is an effective and necessary option for patients with end-stage heart and kidney/liver failure. MOT is ethically permissible, and efforts should be made to consider eligible patients as early as possible to limit morbidity and mortality. Further research is needed regarding appropriate listing criteria and long-term outcomes.

Combined heart and liver transplantation: an updated systematic review

INTRODUCTION

Combined heart and liver transplantation (CHLT) is one of the most complex procedures of surgery that has been implemented in the last 35 years. The aim of our meta-analysis was to investigate the safety and efficacy of CHLT.

MATERIALS

The meta-analysis was designed according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) and AMSTAR (A MeaSurement Tool to Assess systematic Reviews) recommendations. A literature search was conducted up to April 2020 using the MEDLINE,® SCOPUS,® ClinicalTrials.gov, Embase™, Cochrane Central Register of Controlled Trials and Google Scholar™ databases.

RESULTS

Our meta-analysis included 16 studies with 860 patients. The mortality rate following CHLT was 14.1%. One and five-year survival rates were 85.3% and 71.4% while the heart and liver rejection rates were 6.1% and 9.1% respectively. The hospital stay was 25.8 days and the intensive care unit stay was 9.9 days. Pooled values were also calculated for cardiopulmonary bypass duration, units of transfused red blood cells and fresh frozen plasma, postoperative infection rate, mechanical ventilation rate and follow-up duration.

CONCLUSIONS

Despite its complexity, CHLT is a safe and effective procedure for the management of lethal diseases that lead to progressive heart and/or liver failure. Nevertheless, there must be strict adherence to the indications for surgery, and future studies should compare CHLT with isolated cardiac and hepatic transplantations.

Combined heart-liver-kidney transplant: The university of chicago medicine experience

Until recently, combined heart-liver-kidney transplantation was considered too complex or too high-risk an option for patients with end-stage heart failure who present with advanced liver and kidney failure as well. The objective of this paper is to present our institution's best practices for successfully executing this highly challenging operation. At our institution, referral patterns are most often initiated through the cardiac team. Determinants of successful outcomes include diligent multidisciplinary patient selection, detailed perioperative planning, and choreographed care transition and coordination among all transplant teams. The surgery proceeds in three distinct phases with three different teams, linked seamlessly in planned handoffs. The selection and perioperative care are executed with determined collaboration of all of the invested care teams. This article is protected by copyright. All rights reserved.

Heart-After-Liver Transplantation Attenuates Rejection of Cardiac Allografts in Sensitized Patients

BACKGROUND

In patients undergoing heart transplantation, significant allosensitization limits access to organs, resulting in longer wait times and high waitlist mortality. Current desensitization strategies are limited in enabling successful transplantation.

OBJECTIVES

The purpose of this study was to describe the cumulative experience of combined heart-liver transplantation using a novel heart-after-liver transplant (HALT) protocol resulting in profound immunologic protection.

METHODS

Reported are the results of a clinical protocol that was instituted to transplant highly sensitized patients requiring combined heart and liver transplantation at a single institution. Patients were dual-organ listed with perceived elevated risk of rejection or markedly prolonged waitlist time due to high levels of allo-antibodies. Detailed immunological data and long-term patient and graft outcomes were obtained.

RESULTS

A total of 7 patients (age 43 ± 7 years, 86% women) with high allosensitization (median calculated panel reactive antibody = 77%) underwent HALT. All had significant, unacceptable donor specific antibodies (DSA) (>4,000 mean fluorescence antibody). Prospective pre-operative flow cytometric T-cell crossmatch was positive in all, and B-cell crossmatch was positive in 5 of 7. After HALT, retrospective crossmatch (B- and T-cell) became negative in all. DSA fell dramatically; at last follow-up, all pre-formed or de novo DSA levels were insignificant at <2,000 mean fluorescence antibody. No patients experienced >1R rejection over a median follow-up of 48 months (interquartile range: 25 to 68 months). There was 1 death due to metastatic cancer and no significant graft dysfunction.

CONCLUSIONS

A heart-after-liver transplantation protocol enables successful transplantation via near-elimination of DSA and is effective in preventing adverse immunological outcomes in highly sensitized patients listed for combined heart-liver transplantation.

Considerations and experience driving expansion of combined heart-liver transplantation

PURPOSE OF REVIEW

Heart transplantation concomitant with a liver transplant may be warranted when end-stage heart failure results in irreversible liver failure. Previously reported outcomes have been excellent yet the specific immunoprotective role of the liver allograft is not known. We review the current literature about the immunologic benefit for combined heart and liver transplantation (CHLT).

RECENT FINDINGS

The total number of combined heart and liver transplants continues to increase and accounts for approximately 25 cases per year. Familial amyloid polyneuropathy with cardiac cirrhosis is the most common indication for CHLT while adult congenital heart disease (CHD) with associated cirrhosis is increasing in frequency. The majority of recent registry data suggest a statistically equivalent to modestly improved survival advantage for CHLT compared with isolated heart transplantation. Direct mechanisms accounting for this survival advantage are not proven, but combined heart and liver transplants experience lower rates of acute cardiac rejection and cardiac allograft vasculopathy (CAV).

SUMMARY

Combined heart and liver transplants remain a small percentage of the total heart transplants worldwide, but the majority of recent literature confirms the safety and viability of this option for patients with end-stage heart and liver disease. Equivalent to modestly improved survival outcomes, lower rates of acute cardiac rejection and CAV warrant further investigation into the liver allograft's immunoprotective effect on the transplanted heart. The key mechanisms of tolerogenicity have important implications for surgical technique and immunosuppression requirements. Future directions include development of criteria for heart-liver transplant candidacy and identification of equitable allocation protocols.

Immunosuppression considerations in simultaneous organ transplant

Solid organ transplantation is a life-saving procedure for patients in the end stage of heart, lung, kidney, and liver failure. For patients with more than one failing organ, simultaneous organ transplantation has emerged as a viable treatment option. Immunosuppression strategies and outcomes for simultaneous organ transplant recipients have been reported, but often involve limited populations. Transplanting dual organs poses challenges in terms of balancing immunosuppression with immunologic risk and allograft damage from surgical complications. Furthermore, transplanting certain organs can impose considerations on the management of immunosuppression. For example, liver allografts may confer immunologic privilege and lower rates of rejection of other allografts. This review article evaluates immunosuppression strategies for simultaneous kidney-pancreas, liver-kidney, heart-kidney, heart-liver, heart-lung, lung-liver, and lung-kidney transplants. To date, no comprehensive review exists to address immunosuppressive strategies in simultaneous organ transplant populations. Our review summarizes the available literature and provides evidence-based recommendations regarding immunosuppression strategies in simultaneous organ transplant recipients.

Transplant Tolerance Induction: Insights From the Liver

A comparison of pre-clinical transplant models and of solid organs transplanted in routine clinical practice demonstrates that the liver is most amenable to the development of immunological tolerance. This phenomenon arises in the absence of stringent conditioning regimens that accompany published tolerizing protocols for other organs, particularly the kidney. The unique immunologic properties of the liver have assisted our understanding of the alloimmune response and how it can be manipulated to improve graft function and survival. This review will address important findings following liver transplantation in both animals and humans, and how these have driven the understanding and development of therapeutic immunosuppressive options. We will discuss the liver's unique system of immune and non-immune cells that regulate immunity, yet maintain effective responses to pathogens, as well as mechanisms of liver transplant tolerance in pre-clinical models and humans, including current immunosuppressive drug withdrawal trials and biomarkers of tolerance. In addition, we will address innovative therapeutic strategies, including mesenchymal stem cell, regulatory T cell, and regulatory dendritic cell therapy to promote liver allograft tolerance or minimization of immunosuppression in the clinic.

2019 Clinical Update in Liver Transplantation

Liver transplantation continues be the standard for treatment of end-stage liver disease, and even with recent advances in organ preservation, the anesthetic management continues to require understanding of multiple organ systems beyond the liver. Multiple factors contribute to hemodynamic changes after reperfusion of the liver graft that anesthesiologists should be aware of before unclamping. Concomitant renal dysfunction in end-stage liver disease is not uncommon, and preparation for continuous renal replacement therapy may need to be considered in certain cases. Cardiac evaluation of liver transplantation patients with an emphasis on arrhythmias, including atrial fibrillation, can help prevent both intraoperative and postoperative complications detrimental to the patient and graft. Finally, combined liver and thoracic organ transplantations may be indicated for certain disease processes that affect multiple organs. These cases require an understanding of the surgical technique and acknowledgment that some goals of the procedures may be in direct opposition to each other.

Revisiting the liver’s role in transplant alloimmunity

The transplanted liver can modulate the recipient immune system to induce tolerance after transplantation. This phenomenon was observed nearly five decades ago. Subsequently, the liver’s role in multivisceral transplantation was recognized, as it has a protective role in preventing rejection of simultaneously transplanted solid organs such as kidney and heart. The liver has a unique architecture and is home to many cells involved in immunity and inflammation. After transplantation, these cells migrate from the liver into the recipient. Early studies identified chimerism as an important mechanism by which the liver modulates the human immune system. Recent studies on human T-cell subtypes, cytokine expression, and gene expression in the allograft have expanded our knowledge on the potential mechanisms underlying immunomodulation. In this article, we discuss the privileged state of liver transplantation compared to other solid organ transplantation, the liver allograft’s role in multivisceral transplantation, various cells in the liver involved in immune responses, and the potential mechanisms underlying immunomodulation of host alloresponses.

Short-term outcomes of en bloc combined heart and liver transplantation in the failing Fontan

Patients with failing Fontan physiology and liver cirrhosis are being considered for combined heart and liver transplantation. We performed a retrospective review of our experience with en bloc combined heart and liver transplantation in Fontan patients > 10 years old from 2006 to 18 per Institutional Review Board approval. Six females and 3 males (median age 20.7, range 14.2-41.3 years) underwent en bloc combined heart and liver transplantation. Indications for heart transplant included ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, and/or lymphatic abnormalities. Indication for liver transplant included portal hypertension and cirrhosis. Median Fontan/single ventricular end-diastolic pressure was 18/12 mm Hg, respectively. Median Model for End-Stage Liver Disease excluding International Normalized Ratio score was 10 (7-26), eight patients had a varices, ascites, splenomegaly, thrombocytopenia score of ≥ 2, and all patients had cirrhosis. Median cardiopulmonary bypass and donor ischemic times were 262 (178-307) and 287 (227-396) minutes, respectively. Median intensive care and hospital stay were 19 (5-96) and 29 (13-197) days, respectively. Survival was 100%, and rejection was 0% at 30 days and 1 year post-transplant. En bloc combined heart and liver transplantation is an acceptable treatment in the failing Fontan patient with liver cirrhosis.

Heart-Kidney and Heart-Liver Transplantation Provide Immunoprotection to the Cardiac Allograft

BACKGROUND

Prior single-center studies suggest that kidney and liver allografts are immunoprotective toward transplanted hearts. The broader effects of the simultaneous transplantation of kidney or liver on protection from rejection are unclear.

METHODS

The United Network for Organ Sharing database for heart transplantation was queried from 1987 to 2015 and stratified into patients undergoing heart-liver transplantation (HLT) (n = 192), heart-kidney transplantation (HKT) (n = 1,174), and heart-only transplantation (HT) (n = 61,471). Perioperative and follow-up data were compared between HT versus HLT and HT versus HKT groups using analysis of variance (continuous), chi-square test (categorical), and Kaplan-Meier curves (survival).

RESULTS

HKT patients were older (51.2 ± 13.4 years of age) compared with HT patients (45.6 ± 19.2 years of age; p < 0.0001), with higher rate of diabetes (33.8% versus 14.8%; p < 0.0001) and dialysis (49.7% versus 2.1%; p < 0.0001). HKT (46.2%) and HLT (49.5%) patients had more urgent need for transplantation (status 1A) compared with HT patients (32%; p < 0.0001). Acute rejection episodes before discharge were lower in the HLT group (7.1% versus 3.1%; p = 0.03). Ten-year patient survivals were similar for HT (53.6%) versus HKT (56.7%) (p = 0.13) versus HLT (60.4%) (p = 0.09). Treatment for rejection during the first posttransplant year was lower in HLT (2.1%) and HKT (8.4%) compared with HT (17.4%) (p < 0.0001 for both). Cox multivariate analysis showed that cardiac allograft survival was improved in HKT (odds ratio, 0.58; 95% confidence interval [CI], 0.49 to 0.70; p < 0.0001). Additionally, HKT (hazard ratio, 0.52; 95% CI, 0.45 to 0.60; p < 0.0001) and HLT (hazard ratio, 0.24; 95% CI, 0.15 to 0.39; p < 0.0001) were associated with improved freedom from rejection.

CONCLUSIONS

Nationally, HKT and HLT have equivalent postoperative outcomes as HT. Simultaneous kidney or liver transplantation confers an improved clinical and immunologic outcome.

Change in the Content of Immunoproteasomes and Macrophages in Rat Liver At the Induction of Donor-Specific Tolerance

Induction of donor specific tolerance (DST) by the introduction of donor cells into a recipient's portal vein is one of the approaches used to solve the problem of transplant engraftment. However, the mechanism of DST development remains unclear to this moment. In the present work, we first studied the change in the content of immunoproteasomes and macrophages of the liver at early stages of the development of allospecific portal tolerance in rats by Western blotting and flow cytofluorimetry. On the basis of the data obtained, we can conclude that the induction of DST is an active process characterized by two phases during which the level of the proteasome immune subunits LMP2 and LMP7 in liver mononuclear cells, including Kupffer cells, and the number of Kupffer cells change. The first phase lasts up to 5 days after the beginning of DST induction; the second phase - from 5 to 14 days. In both phases, the level of the subunits LMP2 and LMP7 in the total pool of mononuclear cells and Kupffer cells increases, with maximum values on days 1 and 7. In addition, the total number of Kupffer cells increases in both phases with a shift in several days. The most noticeable changes take place in the second phase. The third day is characterized by a lower content of mononuclear cells expressing immunoproteasomes compared to the control value in native animals. Presumably, at this time point a "window of opportunity" appears for subsequent filling of an empty niche with cells of different subpopulations and, depending on this fact, the development of tolerance or rejection. The results obtained raise the new tasks of finding ways to influence the cellular composition in the liver and the expression of immunoproteasomes on the third day after the beginning of DST induction to block the development of rejection.

Single-center outcomes of combined heart and liver transplantation in the failing Fontan

Long-term outcomes of the Fontan operation include Fontan failure and liver disease. Combined heart-liver transplantation (CHLT) is an option for select patients although limited data exist on this strategy. A retrospective review of Fontan patients 18 years or older referred for cardiac transplant evaluation between 2000 and 2013 at the Hospital of the University of Pennsylvania was performed. All patients were considered for potential CHLT. Clinical variables such as demographics, perioperative factors, and short-term outcomes were reviewed. Of 17 referrals for cardiac transplantation, seven Fontan patients underwent CHLT. All patients who underwent CHLT had either advanced fibrosis or cirrhosis on liver biopsy. There were no perioperative deaths. The most common postoperative morbidity was acute kidney injury. Short-term complications include one episode of acute liver rejection but no cardiac rejection greater than 1R. CHLT is an acceptable therapeutic option for patients with failing Fontan physiology who exhibit concomitant advanced liver fibrosis. However, optimal patient selection is currently undefined, and long-term outcomes are not known.

Liver Allograft Provides Immunoprotection for the Cardiac Allograft in Combined Heart-Liver Transplantation

When transplanted simultaneously, the liver allograft has been thought to have an immunoprotective role on other organs; however, detailed analyses in simultaneous heart-liver transplantation (SHLT) have not been done to date. We analyzed patient outcomes and incidence of immune-mediated injury in 22 consecutive SHLT versus 223 isolated heart transplantation (IHT) recipients between January 2004 and December 2013, by reviewing 3912 protocol- and indication-specific cardiac allograft biopsy specimens. Overall survival was similar (86.4%, 86.4%, and 69.1% for SHLT and 93.3%, 84.7%, and 70.0% for IHT at 1, 5, and 10 years; p = 0.83). Despite similar immunosuppression, the incidence of T cell-mediated rejection (TCMR) was lower in SHLT (31.8%) than in IHT (84.8%) (p < 0.0001). Although more SHLT patients had preexisting donor-specific HLA antibody (22.7% versus 8.1%; p = 0.04), the incidence of antibody-mediated rejection was not different in SHLT compared with IHT (4.5% versus 14.8%, p = 0.33). While the left ventricular ejection fraction was comparable in both groups at 5 years, the incidence and severity of cardiac allograft vasculopathy were reduced in the SHLT recipients (42.9% versus 66.8%, p = 0.03). Simultaneously transplanted liver allograft was associated with reduced risk of TCMR (odds ratio [OR] 0.003, 95% confidence interval [CI] 0-0.02; p < 0.0001), antibody-mediated rejection (OR 0.04, 95% CI 0-0.46; p = 0.004), and cardiac allograft vasculopathy (OR 0.26, 95% CI 0.07-0.84; p = 0.02), after adjusting for other risk factors. These data suggest that the incidence of alloimmune injury in the heart allograft is reduced in SHLT recipients.

Organ-specific differences in achieving tolerance

PURPOSE OF REVIEW

When it comes to tolerance induction, kidney allografts behave differently from heart allografts that behave differently from lung allografts. Here, we examine how and why different organ allografts respond differently to the same tolerance induction protocol.

RECENT FINDINGS

Allograft tolerance has been achieved in experimental and clinical kidney transplantation. Inducing tolerance in experimental recipients of heart and lung allografts has, however, proven to be more challenging. New protocols being developed in nonhuman primates based on mixed chimerism and cotransplantation of tolerogenic organs may provide mechanistic insights to help overcome these challenges.

SUMMARY

Tolerance induction protocols that are successful in patients transplanted with 'tolerance-prone' organs such as kidneys and livers will most likely not succeed in recipients of 'tolerance-resistant' organs such as hearts and lungs. Separate clinical trials using more robust tolerance protocols will be required to achieve tolerance in heart and lung recipients.

Combined heart-liver transplantation: a single-center experience

Combined orthotopic heart and liver transplantation (CHLT) is a lifesaving procedure for patients with end-stage heart-liver disease. We reviewed the long-term outcome of patients who have undergone CHLT at the University of Bologna, Italy. Fifteen patients with heart and liver failure were placed on the transplant list between November 1999 and March 2012. The pretransplant cardiac diagnoses were familial amyloidosis in 14 patients and chronic heart failure due to chemotherapy with liver failure due to chronic hepatitis in one patient. CHLT was performed as a single combined procedure in 14 hemodynamically stable patients; there was no peri-operative mortality. The survival rates for the CHLT recipients were 93%, 93%, and 82% at 1 month and 1 and 5 years, respectively. Freedom from graft rejection was 100%, 90%, and 36% at 1, 5, and 10 years, respectively, for the heart graft and 100%, 91%, and 86% for the liver graft. The livers of eight recipients were transplanted as a "domino" with mean overall 1-year survival of 93%. Simultaneous heart and liver transplantation is feasible and was achieved in this extremely sick cohort of patients. By adopting the domino technique, we were able to enlarge the donor cohort and include high-risk patients.

Heart transplantation: challenges facing the field

There has been significant progress in the field of heart transplantation over the last 45 years. The 1-yr survival rates following heart transplantation have improved from 30% in the 1970s to almost 90% in the 2000s. However, there has been little change in long-term outcomes. This is mainly due to chronic rejection, malignancy, and the detrimental side effects of chronic immunosuppression. In addition, over the last decade, new challenges have arisen such as increasingly complicated recipients and antibody-mediated rejection. Most, if not all, of these obstacles to long-term survival could be prevented or ameliorated by the induction of transplant tolerance wherein the recipient's immune system is persuaded not to mount a damaging immune response against donor antigens, thus eliminating the need for chronic immunosuppression. However, the heart, as opposed to other allografts like kidneys, appears to be a tolerance-resistant organ. Understanding why organs like kidneys and livers are prone to tolerance induction, whereas others like hearts and lungs are tolerance-resistant, could aid in our attempts to achieve long-term, immunosuppression-free survival in human heart transplant recipients. It could also advance the field of pig-to-human xenotransplantation, which, if successful, would eliminate the organ shortage problem. Of course, there are alternative futures to the field of heart transplantation that may include the application of total mechanical support, stem cells, or bioengineered whole organs. Which modality will be the first to reach the ultimate goal of achieving unlimited, long-term, circulatory support with minimal risk to longevity or lifestyle is unknown, but significant progress in being made in each of these areas.

The state of the art in heart transplantation

Cardiac transplantation is in its fourth decade as a treatment for end-stage cardiomyopathy and heart failure. It has reached a mature stage in its development as an effective treatment and many issues are settled with respect to best practices. However, there are many areas of ongoing research and significant advances that are continually being recognized. What constitutes 'State of the Art' in heart transplantation? This review focuses on developments in the pretransplant, peritransplant, and posttransplant phases of the care of the potential heart transplant recipient.