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Heart transplantation (HT) is an established treatment for patients with end-stage heart disease in whom all other management options have been exhausted, providing excellent functional capability and a good median-term survival, now exceeding 12 years.1 The two most common causes of heart failure in those undergoing HT are dilated cardiomyopathy (50.5%) and ischaemic heart disease (33.1%).1 Those with congenital heart disease (CHD) form 3.1% of patients reported to the international registry in recent years.1
There are accumulating data indicating that children now born with CHD have an increased chance of living to adolescence, adulthood and even middle age. More than 90% of patients born with CHD are now expected to survive into adulthood2 with an estimated prevalence of CHD in adults of approximately 3000 per million population.3 These patients have benefited from advances in surgical technique and medical therapy, delaying the onset of univentricular or biventricular failure, arrhythmias, pulmonary hypertension and multiorgan failure to an older age.4 Not only does this growing population increase the need for HT but also adds to the diversity and complexity of transplant surgery and immediate postoperative care.
In their Heart paper, Dimopoulos and colleagues report the English experience of HT and combined heart/lung transplantation (HLT) in patients with CHD.4 Over an 18-year period, 469 transplants were performed in 444 patients—with most (82.2%) isolated HT. Based on previous trends, the authors provide a forecast of expected numbers of transplants in patients with CHD over the next 10 years, with a predicted increase of approximately one third. This number lags well behind the need suggested by the rapid increase in patients with CHD requiring repeated hospitalisations for advanced heart failure.4
Barriers to transplantation in patients with CHD
Limited donor numbers
The number of HTs reported to the international registry, which is estimated to be 80% of those performed worldwide, has increased steadily over the last decade but the increase remains in the order of <5% per year,1 reflecting both slowly increasing donor numbers and with more intense logistics and management, greater acceptance of donors offered. This falls well short of the need for growth in the CHD population suggested by Dimopoulos et al.4 An increase in transplants in patients with CHD can be achieved only if donor numbers increase with a similar proportion allocated to patients with CHD or the proportion of transplants performed for CHD increases. As well as the slow but steady rise in total transplant numbers, there are encouraging signals from donation after circulatory death and the increasing use of ex vivo perfusion systems providing time for hormonal resuscitation and longer transportation times. The more extensive use of mechanical assist devices, if used as a bridge to transplantation, merely delays the time to transplant without an increase in the donor pool. The alternative of increasing the proportion of transplants for CHD requires consideration. Dimopoulos et al report 469 transplants over an 18-year period.4 Over the same period, 3352 HT (n=3053) and HLTs (n=299) were performed in the UK,5 providing a proportion of 14%, well above that reported by the International Registry. This suggests that by international standards the English CHD population appears to be well served.
The nature of CHD
The nature of CHD, a lifelong disorder, with associated psychosocial, behavioural, occupational, socioeconomic and medical challenges, sets this group of patients apart, often to their disadvantage, when compared with patients with most other transplant aetiologies. Although the authors describe an increasing number of admissions of patients with CHD with heart failure, the chronicity of CHD and often slow insidious demise make the trigger and timing of reporting of symptoms, referral for assessment, listing and subsequent transplant difficult. These patients are often less acutely ill than others, particularly those with myocarditis or a DCM with exacerbations of heart failure requiring inotropic and mechanical support. It, therefore, happens that even when a decision has been made to list patients with CHD, waiting for a transplant can be long. From the Australasian registry it was found that on average patients with CHD wait 59 days longer from listing to transplant than patients without CHD (237 vs 178 days p=0.08).6 An openness of transplant teams to understand, accept and allow for these often shrouded differences is critical in offering transplantation to patients with CHD at the most appropriate time.
The complexity of CHD
Patients with CHD present unique surgical and perioperative challenges and obstacles to HT and HLT. These include the risks associated with redo surgery, anatomical variances and complexity, requirement for additional tissue, fashioning of conduits, longer operating time and thus longer ischaemic times, renal and hepatic fragility and antibody sensitisation requiring meticulous management of immunosuppressant therapy. Recipients often require a short period of immediate postoperative temporary mechanical support and several returns to the theatre can be expected. This requires an experienced and cohesive surgical and intensive care team. These experienced, transplant capable, congenital teams are far less common and available than general transplant teams and therefore are not associated with every transplant service. Various solutions have evolved in different regions. Transplants in patient with CHD appear to be performed more frequently when a transplant unit is co-located or near a surgical CHD unit. This is by way of ease of referral, ease of multidisciplinary discussion, surgical competence and team experience. In other centres, CHD transplants are performed by a general cardiac transplant surgeon with the assistance of a CHD surgeon, not necessarily from the same institution. Probably the most common situation internationally is that CHD surgeons are not involved or transplants in patients with CHD are rarely performed. Clearly, these varying scenarios impact significantly on access to transplantation, the proportion of transplants performed and outcomes of patients with CHD in a particular centre or region.
Variability in management of CHD
Perhaps before advocating and investing in increasing CHD transplant capacity to address the increasing numbers of potential recipients , we should take stock to address the inequity and variability in access to transplantation across regions. We have already shown that there is great variability in the proportion of transplants performed for CHD internationally. In the five adult Australian and New Zealand adult cardiac transplant units, the proportion performed for CHD varies from 2.6% to 10.4%.6 7 Does a patient with CHD cared for in a ‘strong’ CHD unit have easier access to HT when the need arises? Making the reasonable assumption that the prevalence of CHD is the same across populations served by these units, one must ask why such a variation exists and how inequities can be addressed. What is important is that the right patient with CHD is listed for HT at the right time in a consistent manner. Before advocating for increasing the number of transplants, we must strive to obtain accurate population-based information with regard to need. Relationships between CHD hubs and transplant units need to forged and strengthened such that easy unconstrained dialogue can take place. The introduction of percutaneous transaortic valve implantation has introduced and imbedded the concept of the ‘Heart Team’ developed to foster robust multidisciplinary dialogue and consistent, appropriate and transparent decision-making in the management of patients with significant aortic stenosis. This concept appears to have stood the test of time and entered the guidelines8 as well as expanded into other disciplines such as the management of infective endocarditis. Consideration should be given to the establishment of CHD transplant teams to:
Facilitate easy multidisciplinary dialogue.
Formulate regional guidelines and policies.
Provide educational material to both patients and referrers regarding the appropriate time to refer the appropriate patient.
Provide a point of contact to often distant referrers.
Facilitate access to clinical and imaging information.
Facilitate and undertake the assessment process.
Document discussion and conclusions (audit and dissemination) and database entry/management.
Plan and facilitate the HT operation and logistics with an appropriate CHD experienced surgeon and team to ensure the best possible outcome.
Provide appropriate care and sensitivity to a patient with a lifelong condition particularly with regard to rehabilitation, exercise and social integration.
Although the frequency and nature of meetings and interactions may vary and evolve, a single uncomplicated point of contact for patients, referrers and team can only enhance discussion and ensure seamless referrals and assessments are undertaken, often in locations distant from patient’s homes or units with which they have become very familiar. Consideration should be given to directing initial additional resource into developing such multidisciplinary groups for CHD transplantation in order to determine the true need, providing a sound, indisputable basis on which to advocate growth.
Now that >90% of patients with CHD survive to adulthood, living beyond the age of 50 years has become the new frontier, even for those with complex diseases such as a systemic right ventricle or Fontan circulation. With transplantation providing a median of an additional 12 years of life, longevity can almost be achieved in this population.
The author gratefully acknowledges the database management services of Mr Ross Pettersson, Australia and New Zealand Cardiothoracic Organ Transplant Registry and Secretarial assistance of Charlene Nell for manuscript preparation from the Department of Cardiovascular Services, Green Lane Cardiovascular Services, Auckland City Hospital, Auckland, New Zealand.
Contributors PNR as corresponding and sole author acts as guarantor. He was solely responsible for the manuscript conception and design; analysis and interpretation of data; drafted the article; and final approval of the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Commissioned; internally peer reviewed.
Data sharing statement No applicable.
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