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Eur J Cardiothorac Surg 1998;14:7-14
© 1998 Elsevier Science NL
Department of Cardiothoracic Surgery, Freeman Hospital, High Heaton, Newcastle-upon-Tyne, NE7 7DN, UK
Received 29 September 1997; received in revised form 23 March 1998; accepted 15 April 1998.
Corresponding author. Tel.: +44 191 2843111; fax: +44 191 2231175.
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Abstract |
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 Top Abstract Introduction
Materials and methods
ResultsDiscussion
Conclusions
Appendix A. Conference...References |
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Key Words: Congenital heart disease • Fontan procedure • Cardiac transplantation • Lymphocytotoxic antibodies • Pulmonary vascular disease
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Introduction |
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TopAbstractIntroduction
Materials and methods
ResultsDiscussion
Conclusions
Appendix A. Conference...References |
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Patients with a failing Fontan circulation constitute an important subgroup of the patients with congenital heart disease referred for heart transplantation. Leaving behind the anatomical considerations that have been the focus of earlier reports, this study raises wider issues, questioning the choice of high risk palliative surgery rather than transplantation at the outset and identifying the factors that compromise donor organ selection and peri-operative survival.
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Materials and methods |
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TopAbstractIntroduction
Materials and methods
ResultsDiscussion
Conclusions
Appendix A. Conference...References |
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Complete clinical records were available on all patients with Fontan physiology referred for cardiac transplant assessment. All of these patients were accepted and listed for cardiac transplantation following in-house evaluation. All nine patients underwent cardiac transplantation and all survivors attended local follow-up out-patient clinics. Clinical data pertaining to the initial Fontan procedure and subsequent transplant operation were reviewed.
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Results |
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TopAbstractIntroduction
Materials and methods
ResultsDiscussion
Conclusions
Appendix A. Conference...References |
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The Fontan operations were performed in five pediatric cardiothoracic surgical centres. A variety of surgical techniques were employed (Table 1).
Fontan surgery outcome is detailed in Table 1. Three patients required early surgical re-intervention. Two patients required permanent pacing. Subsequent deterioration was associated with loss of sinus rhythm (four cases) and progressive atrio-ventricular valve regurgitation (seven cases). The interval to transplant assessment was less than 1 year in five cases and between 2 and 12 years in four cases. Patients with dominant right ventricles were referred within 6 months of Fontan surgery. In contrast, patients who had Fontan procedures leaving the hypoplastic right ventricle in the Fontan pathway were referred late.
All patients referred for cardiac transplant assessment were accepted and listed. Three patients had raised lymphocytotoxic antibody titres which necessitated prospective crossmatching. Three patients were on intravenous inotropic support and underwent emergency transplant operations. The waiting time for transplantation ranged between 19 and 103 days. Specific concerns relating to the suitability of donor organs included size mis-match (n=1), history of cardiac arrest (n=1), high intravenous inotrope dependance (n=3), and possible coronary artery disease (n=1). Harvesting techniques were modified to obtain maximal length of the great vessels. Substantial haemorrhage was encountered at the time of resternotomy in three cases and necessitated prompt femoral cannulation. Recipient operations were modified to take account of previous surgery and the congenital anatomical abnormalities. The pulmonary artery was reconstructed using pericardium and modified atrial anastomoses and direct caval anastomoses were constructed as previously described [1]. Total ischemic times ranged from 186 to 335 min. There were six operative survivors. Three patients died within 24 h of operation (two graft failures, one haemorrhage). In the six operative survivors, intensive care stay was 3–16 days, re-ventilation was necessary following initial extubation in three cases, and hospital stay was 14–32 days. There have been no subsequent deaths (follow-up 11–59 months). Four patients have remained entirely free of rejection. All six patients are in NYHA class I/II.
Peri-operative deaths
Patient 1 was 9 years post-Fontan surgery and was on intravenous inotropic support when she underwent emergency transplantation. The donor heart required inotropic support. The calcified homograft conduit was adherent to the back of the sternum and was entered at re-sternotomy necessitating institution of femoral cannulation to establish cardiopulmonary bypass. Right ventricular dysfunction was problematic after weaning from cardiopulmonary bypass. There was persistent bleeding after surgery. The patient died in the presence of multi-organ failure. Permission for post mortem was refused.
Patient 3 underwent cardiac transplantation four months following a Kawashima procedure. The Kawashima procedure was undertaken in the presence of gross common atrio-ventricular valve regurgitation (v wave, 22 mmHg; mean atrial pressure, 12 mmHg) and elevated pulmonary artery pressures (total pulmonary resistance, 8.9 Wood units). During transplant assessment, high pulmonary artery pressures and common atrio-ventricular valve regurgitation were again documented. She had raised lymphocytotoxic antibody titres (100%). The donor heart was inotrope dependant. The patient died in multi-organ failure associated with an inadequate cardiac output from an under-sized donor heart (male donor, 25% weight mis-match). Pulmonary vascular changes and coagulative myocardial necrosis were identified at post-mortem.
Patient 6 was 12 years post-Fontan surgery at the time of cardiac transplantation. He had raised lymphocytotocic antibody titres (25%). The local donor had suffered a prolonged cardiac arrest and was on intravenous inotropic therapy. Echocardiography was performed and ventricular function was deemed satisfactory. The donor heart struggled off cardiopulmonary bypass and failed to maintain an adequate output despite pharmacological support. At post-mortem, there was evidence of ischemic myocardial necrosis. There were no pulmonary hypertensive changes.
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Discussion |
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TopAbstractIntroduction
Materials and methods
ResultsDiscussion
Conclusions
Appendix A. Conference...References |
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(1) In ideal Fontan candidates, functional capacity deteriorates with time; the instantaneous risk of death from cardiac failure progressively increases from two years postoperatively; overall risk of death increases from 6 years postoperatively (survival at 1 month, 5 years, 15 years: 90%, 86%, 74%, respectively) [5].
(2) The selection criteria for Fontan surgery have been relaxed and Fontan operations are being performed in a wider spectrum of congenital cardiac conditions that are unsuitable for bi-ventricular repair. After high-risk Fontan operations in patients who do not fulfil the ideal selection criteria, there is increased risk of postoperative arrhythmias, early and late cardiac failure, and death. The attrition rate is much greater in the first 6 months after surgery [6].
Incremental risk factors for death after Fontan procedures include older age at operation, left AV valve atresia, main chamber hypertrophy, McGoon ratio, higher preoperative pulmonary artery pressures, type of operation (RA to PA rather than RV connection, RA to PA valved conduit), prolonged cardioplegic time or non-use of cardioplegia), and elevated postoperative right atrial pressure [5] [6]. Factors involved in deterioration include progressive atrio-ventricular valve regurgitation, loss of sinus rhythm, deterioration in performance of the systemic ventricle (more rapid if the systemic ventricle has right ventricular morphology), and changes in the pulmonary vasculature [7]. Modification to operative technique may impact on eventual outcome but follow-up data is not yet available. Staged total-cavo-pulmonary connections utilising a manhole cover patch to facilitate completion and extra-cardiac conduits are being performed in an attempt to preserve atrial rhythm and contractility, avoid atrial distension and thrombus formation, and minimise energy losses to bloodflow. Construction of extra-cardiac conduits performed on beating hearts on cardiopulmonary bypass without the need for aortic cross-clamping or cardioplegia, may preserve ventricular function in the longterm [8] [9].
In this series of transplant referrals, patients did not fulfil the classic ideal criteria for a Fontan procedure and subsequently conformed to recognisable patterns of Fontan failure (Table 1). The number of patients who required transplantation so soon after Fontan surgery raises a fundamental question. Can cardiac transplantation achieve a better outcome than high-risk Fontan surgery at the outset? The role of transplantation in patients unsuitable for bi-ventricular repair who are high-risk Fontan candidates has yet to be properly evaluated. Other authors have commented that high risk Fontan is not simply cost-ineffective, but that it is bad medical practice [6] [10]. In this study, the original Fontan procedures were performed at five cardiothoracic surgical centres and data pertaining to the overall population undergoing Fontan surgery in these centres were not evaluated. Nevertheless, the facts remain that there are a group of patients for whom Fontan surgery delivers only a very brief respite prior to transplant referral, that the quality of life is un-satisfactory during that short interval, and that previous Fontan surgery impacts on transplant outcome in both adults and children.
Do the results justify cardiac transplantation for the failing Fontan population? Six of nine patients have survived transplantation. In survivors, the subsequent clinical course is comparable to other cardiac transplant subgroups. Three of nine patients died following transplantation and these were peri-operative deaths. Fig. 1 illustrates that this pattern conforms to the outcome profile of the overall congenital subgroup.
Why should the Fontan population undergoing cardiac transplantation have increased perioperative morbidity and mortality? The three deaths in our series resulted from a combination of factors.
(1) Pulmonary vascular resistance: pulmonary vascular changes cannot be accurately identified during recipient transplant assessment prior to listing or immediately prior to implantation. Following a Fontan procedure, calculation of low pulmonary vascular resistance is meaningless. Vascular resistance is proportional to flow. The Fontan circulation involves loss of hydro-dynamic energy during passage of blood through the vena cavae to the pulmonary arteries, pulmonary bloodflow is reduced, and left and right pulmonary bloodflow distribution is not equal. Furthermore, it cannot be presumed that patients who have undergone Fontan surgery in the presence of normal pulmonary vascular resistance have a protected pulmonary vasculature: repeated thrombo-emboli and micro-vascular sludging occur within the pulmonary vessels; in the absence of hepatic factors entering the pulmonary circulation following Fontan procedures, patients are predisposed to arterio-venous malformations [11] [12] [13]. If pulmonary vascular changes cannot be identified, then it is sensible to anticipate right heart problems following implantation, avoid undersized donor hearts, and minimise ischaemic times. At present, the inability to identify patients with pulmonary vascular changes, the donor shortage, and better results after cardiac transplantation predicates against offering these patients heart-lung transplantation.
(2) Acceptance of sub-optimal donor hearts: donor organs are in short supply. The overall attrition rate on the heart transplant waiting list in the United Kingdom is 15–20% per annum [14]. Individuals can be disadvantaged by blood group, weight, or antibody status. When a potential donor heart is offered, the suitability as a donor organ is assessed and a suitable recipient is selected from the waiting list. There are times when the needs of several suitable candidates on the waiting list must be prioritised and times when certain established donor selection criteria must be ignored. We endeavour to make the best use of a limited resource.
The presence of raised recipient lymphocytotoxic IgG class antibodies, which have arisen in response to previous blood transfusion, necessitates prospective cross-matching to avoid hyperacute rejection. Panel and specific reactivities are determined at the time of transplant assessment. One third of the failing Fontan patients had IgG reactivity. The logistics involved in obtaining the cross-match must be taken into account when suitable donor organs become available. Due to the limits on cold ischaemic time, this restricts the choice of suitable organs to local donors which make up only a small proportion of the organs offered to each transplant unit. Therefore, the decision to accept a less than ideal donor heart which has been offered locally must be considered carefully. The functional and clinical status and rate of deterioration of the recipient, the recipient's blood group and weight, and the status of other suitable recipients on the transplant waiting list and the likelihood of these patients obtaining a suitable organ must taken into account.
Patients with a failing Fontan circulation should be referred early to the transplant team for assessment and followed closely to identify the optimal time for listing. On-going surveillance is necessary to monitor the rate of deterioration and ensure that their priority status on the waiting list is appropriate. However, sudden deterioration cannot always be foreseen. There will always be patients who need emergency transplantation in spite of such vigilance.
Patients who are deteriorating rapidly can be kept alive with intravenous inotropic agents for very limited period. If respiratory support is needed, the decision to ventilate these patients is taken in the knowledge that there is a very narrow window for transplantation. It is our experience in the Fontan subgroup (and in the overall transplant population) that high salvage rates are achieved if good quality and suitably-matched donor hearts are found for these patients. Therefore, we feel fully justified in this use of donor hearts. The sickest patients need the best donor hearts. However, sub-optimal donor organs will continue to be considered for patients who are rapidly deteriorating and for whom death is imminent when suitable donor hearts cannot be found. These are organs which would be deemed unsuitable for a stable patient on the waiting list and may be intrinsically poor (i.e. have been maintained for protracted periods on high dose inotropes, have suffered cardiac arrests, or, on inspection, have evidence of coronary artery disease), or undersized, or both. The chance of a successful outcome is inversely proportional to the number of un-desirable donor criteria or match-related factors.
(3) Peri-operative bleeding: re-sternotomy resulted in significant haemorrhage in three of the nine cases necessitating prompt femoral cannulation. Our practice has been to expose the groin area for femoral cannulation prior to re-sternotomy. Femoral cannulation can be difficult and cannulation of the neck vessels as practised for extracorporeal membrane oxygenation (ECMO) may be a useful alternative in the future. Excessive postoperative bleeding has not been encountered in any patient undergoing cardiac transplantation for congenital heart disease in this unit since we elected to use aprotonin routinely.
The failing Fontan sub-group must not be considered in isolation. All cardiac transplant candidates compete for the same limited donor heart pool. The relative merits of this activity must be evaluated. The comparative survival data shown in Fig. 1 should not be mis-interpreted and should not give rise to concerns regarding the justification for transplanting patients with congential heart disease. Cardiac transplantation for congenital heart disease currently accounts for only 10% of heart transplant activity and, therefore, patient numbers are relatively small. The overall results of cardiac transplantation for congenital heart disease have improved with increasing experience both in our own practice and in other centres. In recent reports, the overall peri-operative mortality in congenital heart disease is not significantly higher than in acquired cardiac conditions [2] [3] [4]. This series highlights the fact that, in the Fontan subgroup, there are specific recipient factors which place added restraints on donor organ selection and that outcome is largely determined by the availability of suitable donor hearts. We must conclude that this analysis is encouraging because it demonstrates that transplantation is likely to be successful if suitable donor organs can be found. Peri-operative bleeding has been the other major factor and this appears to have been ameliorated by the use of aprotonin routinely. Operative survivors can expect an excellent quality of life and the longterm outcome is similar to that achieved for matched age cohorts in the other subgroups. Continued use of donor organs for transplantation of the Fontan subgroup is fully justified.
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Conclusions |
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TopAbstractIntroduction
Materials and methods
ResultsDiscussion
Conclusions
Appendix A. Conference...References |
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Acknowledgments |
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Footnotes |
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Appendix A. Conference discussion |
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TopAbstractIntroduction
Materials and methods
ResultsDiscussion
Conclusions
Appendix A. Conference...References |
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What is your suggestion as to how to put these patients on extracorporeal circulation with the results that you obtained with bleeding and resternotomy? What is your current policy there?
Mr Carey: Our approach is individualised. At the very least, we expose the femoral site for cannulation. We prepare the patients for femoral cannulation, particularly if there is a conduit behind the sternum, institute femoro-femoral cardiopulmonary bypass, and cool the patient prior to sternotomy. It has been suggested that cervical cannulation, as implemented for ECMO, may be an alternative in selected patients. In non-transplant re-sternotomy, we have found the cervical technique to be excellent. We have not yet employed this technique in the transplant group.
Dr Haverich: I think it is an important consideration. On the other hand, in small children, it may be very difficult to achieve. So I think we have to develop strategies there.
Could I ask you a question about your logistics. We know that also in heart-lung transplantation candidates with previous operations that it will take much longer to get to the point where you can implant the donor heart. How much excess time do you allow between donor heart retrieval and scheduled implantation in these patients?
Mr Carey: In general, we calculate the expected interval between application of the aortic cross-clamp in the donor and expected time of arrival in the operating theatre at the base hospital, add the time estimated to be necessary for the anaesthetist to prepare the patient, and judge the time for take-down of previous shunts, donor heart explantation, and re-constructions. As we have shown, there has been a wide variation in ischemic times.
Dr Haverich: How did you deal with the left-sided superior vena cava in these two patients?
Mr Carey: We used the innominate vein from the donor.
Dr Haverich: But this is also important, not only logistically, but also, donor organ retrieval. You also need a lot of pulmonary artery. How do you get along with the lung transplant surgeons there? And you need a lot of venous material in the upper portion so you can modify your implant procedure.
Mr Carey: Yes, we do take as much donor conduit as possible. When the lungs are not being retrieved, the pulmonary arteries can be taken out to the hilum. The length of pulmonary artery required is dependant both on recipient anatomy and previous surgery and donor vessel to the hilum is not always needed. In the recipient, previous shunts are taken down and the pulmonary artery is patched at this site using pericardium. The donor pulmonary artery may then be anastomosed to the recipient's main pulmonary artery trunk or to the recipient's right or left pulmonary artery. If a homograft conduit is in situ, the homograft is trimmed back and a direct pulmonary artery anastomosis is possible in the usual fashion. In the United Kingdom, we have a zonal retrieval system for donors over 30 kg. Each regional transplant unit is responsible for harvesting potential organs arising within its designated zone. The regional unit has primacy for use of these organs but if they have no suitable recipient, the organs are offered elsewhere via national co-ordinators but still retrieved by the zonal team. We endeavour to achieve maximal use of organs. The pediatric thoracic transplant teams travel whatever distance are required to retrieve organs from small donors if the regional transplant centre has not a pediatric thoracic transplant program.
Dr Haverich: So what is your suggestion to the group here for donor retrieval in terms of timing and in terms of anatomy of the donor?
Mr Carey: The surgeon performing the retrieval should be familiar with the characteristics and surgical history of the proposed recipient and should have discussed the plan for recipient reconstruction. The harvesting surgeon needs to dissect the vessels out to achieve the maximum length that might be needed for recipient reconstructions. The essential difference from our standard technique for heart-lung block retrieval is in preservation of the left brachiocepahalic vein and superior vena cava.
The timing is vital and close communication between the retrieval team and the recipient team is required at each stage of harvesting to minimise ischemic time.
Dr Pettersson (Copenhagen, Denmark): I think that your resulting three deaths illustrate a combination of poor donor and poor recipient. If you have an emergency case, it is my experience that it is unwise to try to solve this recipient's problem by accepting a poor donor heart. A poor recipient really needs a good heart. So you should not compromise when it comes to the donor heart.
I would like to ask you about transplantation in case of protein-losing enteropathy. I assume that you did not study such a case.
Mr Carey: That is correct.
Dr Pettersson: But would that be an indication or a contraindication for you?
Mr Carey: We have not encountered patients with protein-losing enteropathy (PLE). However, Dr. Ouaegebeur in New York has presented his series of 16 patients at a recent meeting in London, four of whom died perioperatively. There were patients for whom cardiac transplantation was performed in the presence of protein-losing enteropathy in this series. The causes of death were unrelated to PLE but similar to those we have presented from our unit (i.e. bleeding and low cardiac output). It is not a contraindication.
While these aspects are relevant, a major issue raised by the presentation is more fundamental. We need to examine the current rationale for Fontan-type procedures in high-risk Fontan candidates because the morbidity and mortality of transplantation following unsuccessful Fontan is so much higher. On the basis of these results, transplantation should be considered at the outset. The problem is in risk-stratification of less-suitable Fontan candidates. In our series, the original Fontan operation had been performed in several centres. We need a wider audit to evaluate the perioperative variables and decision process involved in the denominator group.
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References |
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TopAbstractIntroduction
Materials and methods
ResultsDiscussion
Conclusions
Appendix A. Conference...References |
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