Fontan Ten Commandments Revisited and Revised

Choussat’s “Ten Commandments”, to describe the components of an ideal Fontan candidate, were first published in 1977 [Table1]. These guidelines though modified slightly by various centers have served clinicians well these past thirty two years in helping direct which patients could safely be staged towards Fontan palliation with a high probability of success. Despite the wisdom of these commandments, it is clear from a historical perspective that total compliance with all criteria does not necessarily portend excellent long-term survival as Kaplan-Meyer survival curves demonstrate a disturbing attrition trend. Given this fact and the advancements made in catheter/ interventional techniques, surgical and hybrid techniques and advancements in imaging modalities to guide invasive techniques we believe it is time to modify the original commandments with the end-point being an improvement in survival. We suggest the following single commandment, “Thou Shalt Be Perfect”.

At the recent World Congress Pediatric Cardiology meeting in Cairns, Australia, Professor James Wilkinson presented a lecture entitled, “The Fontan Ten Commandments; have they doubled or halved?” His conclusions were that the original Ten Commandments could be condensed to four of the original ten.
He argued that age less than and not older than four years is now the norm as earlier palliation has become standard in most centers. Abnormalities of systemic venous return can be overcome with bilateral cavopulmonary shunts and re-routing surgical procedures. Right atrial volume is not important as the classic Fontan has been replaced with either the lateral tunnel or extracardiac baffle. Small and/or distorted pulmonary arteries can be plastied from hilum to hilum and mitral valves can be repaired at the time of surgery.

Even Dr. Wilkinson’s modifications however do not take into account subtle residual defects which can conspire to induce irreversible changes to the myocardium leading to attrition. Without highlighting these residual defects, clinicians, when contemplating repair, often apply the same criteria to univentricular hearts that they would apply to biventricular hearts which obviously have more reserve. Common examples include mild aortic arch obstruction, branch pulmonary stenosis, mild to moderate degrees of atrioventricular and semilunar valve insufficiency, and aortopulmonary collateral flow.

Mild degrees of aortic arch obstruction are common following Norwood palliation for hypoplastic heart syndrome. The generally accepted criterion for intervention in a biventricular heart is a peak to peak gradient of 20 mm Hg. This criterion, though arbitrary by itself, has been even more inappropriately applied to univentricular hearts despite the fact that studies have shown peak systolic gradients less than 20 mm Hg can cause significant diastolic dysfunction. With advances in catheter/interventional techniques alone or with hybrid (surgical/catheter) techniques it is possible to completely abolish aortic arch gradients. Cheatham et al has demonstrated that even complex transverse aortic arch obstructions can be successfully approached with open cell design stents allowing crossed head vessels to be re-dilated if needed. Stern et al has demonstrated the safety and efficacy of a new pre-mounted stent (which can be re-dilated to 20 mm) in dilating vascular stenosis in infants and toddlers. Is it reasonable therefore to accept any arch gradient in a univentricular heart which is already exposed to increased afterload?!

Likewise pulmonary artery narrowing or distortion can be approached in the same manner as aortic arch obstructions equalizing pulmonary blood flow and decreasing already elevated caval and lymphatic pressures in addition to reducing the total resistance the single ventricle faces.

With the advent and common application of 3-D echocardiography it is clear that better imaging techniques provides the surgeon with a better understanding of atrioventricular and semilunar valve anatomy and in turn the pathology behind regurgitation unique to each patient. This allows the surgeon, as never before, to plan preoperatively and execute an operation to either eliminate or make trivial these valvular abnormalities.

Finally aortopulmonary collateral vessels are known to be detrimental in single ventricle patients, although their anatomy is poorly described in the literature and the technique to obliterate these vessels has only recently been published. Elimination of chronic volume loading and competitive flow in addition to earlier cavopulmonary shunting (age four months) is absolutely essential we believe. In combination with managing other residual defects as noted above this should allow for better and longer lasting palliation.

Patients with single ventricle anatomy represent a unique challenge to the cardiologist caring for these patients. Only by pre-emptive and aggressive management of these patients will clinicians begin to see an impact on Kaplan-Meyer survival curves for the better. We recommend that clinicians revise Choussat’s Ten Commandments to one simple commandment;” Thou Shalt Be Perfect”. We have the technology. We should strive to do so.

Table 1
Choussat et al (1977) delineated selection criteria to define an ideal candidate for a Fontan procedure.8 They described the 10 following criteria, which are occasionally and facetiously referred to as the 10 commandments for an ideal Fontan operation.
• Age older than 4 years
• Sinus rhythm
• Normal systemic venous return
• Normal right atrial volume
• Mean pulmonary artery pressure less than 15 mm Hg
• Pulmonary arteriolar resistance less than 4 Wood units/m2
• Pulmonary artery–aorta ratio more than 0.75
• Left ventricular ejection fraction more than 0.60
• Competent mitral valve
• Absence of pulmonary artery distortion

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ABOUT THE AUTHOR: Herbert J Stern MD, FACC, FSCAI
Dr. Stern is a board certified pediatric cardiologist specializing in congenital heart disease in adults and pediatrics, therapeutic cardiac catheterization with special interests in hybrid (surgical/catheter) procedures; in stroke and migraine patients who have been diagnosed with a patent foramen ovale; congestive heart failure management, patients with single ventricle physiology and pulmonary hypertension.

Copyright Herbert J Stern MD, FAAP, FACC, FSCAI

Disclaimer: While every effort has been made to ensure the accuracy of this publication, it is not intended to provide legal advice as individual situations will differ and should be discussed with an expert and/or lawyer.For specific technical or legal advice on the information provided and related topics, please contact the author.