However beautiful the strategy, you should occasionally look at the results—W. Churchill
Central Message
Fontan circuit. You should occasionally look at the results!!
See Article page 372.
How often are we delusional, even in our most simple beliefs? We have for long implanted 18-mm or 20-mm Gore-Tex conduits (W. L. Gore & Associates, Inc, Flagstaff, Ariz) as extracardiac Fontan conduits because we believed that this was the size of an adult inferior vena cava and we wanted to have the most streamlined venous. Patel and colleagues
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report in this issue of the Journal a detailed analysis of Fontan circuit sizes by both magnetic resonance imaging and catheterization in 156 patients over a mean follow-up period of 10 years. They correlated these results with hemodynamic and cardiopulmonary data. Their goal was to identify whether a decrease in Fontan conduit size affected cardiac output, pulmonary artery growth, and exercise capacity. Their results should inspire us humility.They demonstrated that the size of the conduit decreases drastically over time. A rapid decrease in size of the conduit had already been described in a smaller series.
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In a much larger group and in more detail, the authors' results are impressive. The conduits had a smaller area of circumference that was a third smaller than expected for the 18- and the 20-mm conduits and a quarter for the 16 mm. So, when we put an 18-mm conduit in a patient, that is not what this patient is receiving. In addition, it seems to occur as early as 6 months after surgery, regardless of initial conduit diameter. There were no association between these restrictions and pulmonary artery growth or cardiac index but, not surprisingly, patients with smaller conduit surface area had worse exercise capacity.This work will not provide us all the answers that we need. We do not know whether their calculated smallest surface area is representative of the restriction to the flow of the entire conduits. We want to know the ideal size of the conduit, but the authors found that, paradoxically, patients implanted with 20-mm conduits had actually worse exercise capacity. We therefore still do not have an answer to this basic question.
The only very clear firm conclusion of this work is that restrictions in the Fontan pathway will lead to decreased exercise capacity. It should be clear that we should not wait to have a pressure gradient through a restriction in this pathway to intervene. It has now been demonstrated that catheter intervention in the Fontan conduit can be successful with minimal morbidity.
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The surprising findings of this manuscript should encourage us to investigate further even the simplest acts that we are performing. It should also open our minds to other innovative solutions. The question today for this growing population is whether we can improve their circulation.5
Putting an adult size conduit in at a small age might not work because it is getting naturally adapted to the optimal size for that small age, remaining small thereafter. Maybe this work shows us that the Fontan circuits should have iterative dilatation/stenting as they grow. One thing is sure, we should not take anything for granted and, as said by Winston Churchill, “However beautiful the strategy, you should occasionally look at the results.”References
- Progression in Fontan conduit stenosis and hemodynamic impact during childhood and adolescence.J Thorac Cardiovasc Surg. 2021; 162: 372-380.e2
- Mid-term follow-up of the status of Gore-Tex graft after 426 extracardiac conduit Fontan procedure.Eur J Cardiothorac Surg. 2009; 36 (discussion 67-8): 63-67
- Reintervention and survival in 1428 patients in the Australian and New Zealand Fontan registry.Heart. 2020; 106: 751-757
- Fate of the Fontan connection: mechanisms of stenosis and management.Congenit Heart Dis. 2019; 14: 571-581
- Are we getting closer to identifying the best follow-up and management after Fontan completion?.J Thorac Cardiovasc Surg. July 4, 2020; ([Epub ahead of print])
Article info
Publication history
Published online: November 22, 2020
Accepted:
November 16,
2020
Received in revised form:
November 14,
2020
Received:
November 14,
2020
Footnotes
Disclosures: The authors reported no conflicts of interest.
The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.
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Copyright
© 2020 by The American Association for Thoracic Surgery
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- Progression in Fontan conduit stenosis and hemodynamic impact during childhood and adolescenceThe Journal of Thoracic and Cardiovascular SurgeryVol. 162Issue 2
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