Is the Extracardiac Conduit the Preferred Fontan Approach for Patients With Univentricular Hearts?

> “In theory, theory and practice are the same. In practice, they are not.”> > —Albert EinsteinThere is, perhaps, no disease entity that better exemplifies the complexities, challenges, and creative innovations characteristic of the evolution in congenital heart disease care than the univentricular heart. The univentricular heart encompasses an array of uncommon and severe inborn cardiac malformations that share a similar physiology, with pulmonary and systemic venous return predominantly directed into a functionally single ventricle, precluding biventricular repair.1 A prevalence of ≈1 per 3000 live births has been estimated.2,3 The occasional patient may survive beyond middle age without palliative surgery when certain conditions align, including well-balanced pulmonary and systemic circulations and preserved function of a morphologically left single ventricle.4 For the vast majority, the prognosis without surgical intervention is grim.5 In developed countries, most patients undergo a staged surgical approach in view of an ultimate, albeit imperfect, Fontan procedure. Typically completed at between 18 months and 4 years of age, Fontan surgery essentially separates the systemic from pulmonary circulation by directing systemic venous return to the pulmonary artery, usually without an interposed subpulmonary ventricle.Response by Kogon on p 2525Since its original description in 1971,6 multiple modifications and adaptations to the Fontan procedure have been widely applied to the spectrum of univentricular hearts. Although it is beyond the scope of this article to detail all proposed variants, the 3 most common categories of Fontan surgery are schematically depicted in Figure 1. The classic Fontan consisted of a valved conduit between the right atrium and pulmonary artery. It was subsequently modified to a direct anastomosis of the right atrium to a divided pulmonary artery (Figure 1A). The intracardiac lateral tunnel was the next major innovation. It consists of an end-to-side anastomosis of the superior …