Author + information
- Yves d’Udekem, MD, PhD∗ ()
- Department of Cardiac Surgery, Royal Children’s Hospital, Melbourne, Victoria, Australia
- Department of Heart Research, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
- Department of Pediatrics, University of Melbourne, Melbourne, Victoria, Australia
- ↵∗Address for correspondence:
Dr. Yves d’Udekem, Department of Cardiac Surgery, Royal Children’s Hospital, Flemington Road, Parkville, Melbourne, Victoria 3052, Australia.
Some investigators are now estimating the population of patients surviving after a Fontan procedure to be approximately 50,000 to 70,000 around the world, and this population will double within 2 decades (1,2). This population is today mainly made of active young adults, born with the most extreme cardiac congenital lesions, and certain to face a heavy disease burden. Improvements in the management of these patients is crucial, and therefore the work of the Pediatric Heart Network, which has already produced a wealth of data, should be lauded (3). In this issue of the Journal, Atz et al. (4) present the long-awaited third assessment of a large set of patients who have undergone detailed and consistent investigations.
Over the last decades, our community has reacted emotionally to the description of adverse outcomes after Fontan procedures, with predictions of certain death to these patients within decades, predictions that were not later confirmed. Similar reactions may be produced by some of the findings of this study. One should not lose sight that the survival of this population was excellent over the 10-year period studied, spanning from 7 to 18 years after Fontan procedures. The reality is that the majority of this population has done well, and the seemingly negative news brought by the study should be interpreted with caution. After this study, one would feel entitled to believe that all patients with Fontan circulation will face an ongoing decrease of ventricular function and exercise capacity. The large, heterogeneous group of patients comprising this Pediatric Heart Network study includes some groups of patients who may have altered the overall results. Close to 15% of these patients had an atriopulmonary connection and were enrolled in the study after their second decade; we know that the condition of a significant proportion of these patients would deteriorate within this time period (3).
The other group at risk of failure of the Fontan circulation, probably better represented in the younger portion of this cohort, are those survivors of complex Norwood procedures who were operated on in recent times. Approximately one-third of the patients underwent this surgical procedure in this cohort. It has been repeatedly demonstrated that in the decade preceding enrollment in this cohort, my colleagues and I (5,6) saw improvement in survival of the first stages of the Norwood operation. There is little doubt that the correlate of this improved survival through the first stages of this palliative procedure was the selection of survivors of Fontan procedures who had a worse outlook than their predecessors. Atz et al. (4) identified at the time that we were facing a subset of patients with right ventricular morphology and “poorer ventricular and valvular function” that were in need of “effective strategies.” We expected patients with old atriopulmonary Fontan procedures and the Norwood operations in younger survivors with poor ventricular function to fail, and there is no doubt that these 2 groups heavily influenced the findings of this study. This young group of patients with heart failure may explain the odd finding that patients who were younger at enrollment had a worse decrease of their exercise capacity than older patients. Although the ventricular function and exercise capacity of the whole group was observed to decrease, it is still uncertain whether these changes affected all patients. Between 7 and 18 years after Fontan procedures, some patients’ conditions were deteriorating, but clearly some other patients may have thrived.
The finding that these patients were observed to have decreased ventricular function is concerning because, up to now, investigations of ventricular function have arisen from cross-sectional or small longitudinal studies. Whether this decrease of ventricular function is the correlate of the failure of the Fontan circulation or its cause and whether it affects all patients or only some remain to be demonstrated. The current findings call for the accumulation of longitudinal data in more homogenous groups of patients.
Today, the only markers of deterioration of Fontan circulation are death and cardiac transplantation. Because of a lack of large studies incorporating detailed investigations of patients, the impact of the physical status of the patients on these outcomes has been unclear. The most remarkable finding of this study is likely that the outcomes of these patients do not seem to be influenced by morphological profile, particularly the nature of the systemic ventricle; however, these outcomes are intimately linked to the patients’ clinical status. Patients with failure of their Fontan circulation are those who have the worse ventricular function and worse exercise capacity. The questionnaire detailing the physical activity of the patients was the best predictor of late outcomes. Could it be that physical activity prevents the ongoing demise of Fontan circulation? There is emerging evidence that increasing the muscle mass may increase the cardiac output of these patients (7). We have nothing to offer in terms of prevention to this population, and improving their cardiopulmonary fitness is an avenue that is worth exploring. There seem to be potential benefits beyond mere survival: in this study, there was a close correlation between quality of life and exercise capacity.
Patients with lower resting oxygen saturation at first enrollment in the cohort had worse outcomes, but it is difficult to know whether this was a marker of impaired Fontan circulation, whether the patient was perceived to be at worse prognosis and left with an open fenestration, or whether lower oxygen saturation caused deterioration of the circulation. This issue should be elucidated because there are still teams of surgeons who believe that leaving the fenestration open benefits patients in the long term and do not close the fenestration for this reason.
Atz et al. (4) also characterize the burden of disease better than ever before. A staggering one-third of these patients required reoperation, and two-thirds needed a catheter reintervention. The reasons for such high rates of reinterventions warrant further investigation. They also reveal wide variations in indications for cardiac transplantation. One center had a higher mortality rate and transplantation rate, likely because of historical data or referral bias. Interestingly, beside this last center, the one with the highest rate of cardiac transplantation had the lowest mortality rate. Today, it becomes increasingly clear that cardiac transplantation in patients who have undergone Fontan procedures may achieve survival comparable to cardiac transplantation for other conditions, but access to transplantation has been limited in certain areas (8). Most current guidelines dictating access to cardiac transplantation are disadvantaging patients with Fontan circulation because these patients can only rarely be adequately supported with mechanical circulatory support. The degradation of these patients’ condition is slow and rarely depends on systolic dysfunction, so these patients are rarely under inotropic support at the time of their listing. In a time of limited access to donor organs, the indications for cardiac transplantation for patients with Fontan circulation should be discussed more openly. This work helps us to identify those patients at higher risk of failure of the Fontan circulation, and it is likely that early listing of these patients before comorbidities develop will give these difficult transplantations a better chance of success.
In the meantime, the only advice that I will keep giving to the young patients who are coming to see me after Fontan procedures is “Exercise, exercise, exercise!”
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the author and do not necessarily represent the views of JACC or the American College of Cardiology.
The Operational Infrastructure Support Program of the Victorian Government of Australia supported this research project. Dr. d’Udekem is an Australian National Health and Medical Research Council Clinical Practitioner Fellow (1082186); and is also a consultant for Merck Sharp & Dohme and Actelion.
- 2017 American College of Cardiology Foundation
- Jacobs J.P.,
- Mayer J.E.,
- Mavroudis C.,
- et al.
- Anderson P.A.,
- Sleeper L.A.,
- Mahony L.,
- et al.
- Atz A.M.,
- Zak V.,
- Mahony L.,
- et al.
- d’Udekem Y.,
- Xu M.Y.,
- Galati J.C.,
- et al.
- Tweddell J.S.,
- Hoffman G.M.,
- Mussatto K.A.,
- et al.
- Shi W.Y.,
- Yong M.S.,
- McGiffin D.C.,
- et al.