FIG 73.3 Original schematic representation of the Kreutzer technique for the first atriopulmonary anastomosis A homograft was inserted between the right atrial appendage and main pulmonary artery without valve implantation in the inferior vena cava (From Kreutzer G, Galíndez E, Bono H, et al An operation for the correction of tricuspid atresia J Thorac Cardiovasc Surg 1973;6[4]:613–621.) The atriopulmonary connection became the standard Fontan modification through to the late 1980s However, over the long term, this circulation was associated with progressive dilatation of the systemic venous atrium, atrial thrombus, and intractable atrial arrhythmia In a series of elegant hydrodynamic experiments, de Leval demonstrated the energy loss associated with the atriopulmonary anastomosis and potential for greater circulatory efficiency if much of the right atrium was excluded from the systemic atrial pathway by using an interatrial patch This technique—termed the total cavopulmonary connection4 or lateral tunnel Fontan—reduced the degree of turbulence and energy loss and improved overall hemodynamics Shortly after, the extracardiac conduit was introduced by Marcelletti et al by interposing a prosthetic valveless conduit to connect the inferior vena cava to the pulmonary artery.5 This aimed to avoid progressive atrial dilation, late tachyarrhythmia, and sinus node dysfunction by reducing the number of suture lines and the pressure load within the right atrium (Fig 73.4) FIG 73.4 Fontan surgical techniques: classical atriopulmonary Fontan (A), lateral tunnel (B), and extracardiac conduit (C) ASD, Atrial septal defect; IVC, inferior vena cava; RA, right atrial; RPA, right pulmonary artery; SVC, superior vena cava (From d'Udekem Y, Iyengar AJ, Cochrane AD, et al The Fontan procedure: contemporary techniques have improved longterm outcomes Circulation 2007;116[11 suppl]:I157–164.) Currently, both the lateral tunnel and extracardiac conduit are widely used, some preferring the former technique in younger patients and those with anomalous drainage of their hepatic veins Studies demonstrate comparable hemodynamics in both circulations.6–8 Nevertheless the extracardiac conduit is the preferred technique in many centers because of the perception that it will be associated with a reduced late arrhythmia burden, although to date this has not been reliably demonstrated.9,10 Late Outcome With a Fontan Circulation As the fifth decade of Fontan surgery approaches, the burden of late morbidity and mortality has become apparent, with the risk of complications and death increasing the longer the duration of the Fontan circulation.11 Late outcome studies report a survival rate of 60% to 80% 20 years post-Fontan surgery.12–14 Variable case selection and duration of follow-up likely account for this range in outcome At 25 years after Fontan surgery, almost half the cohort is predicted to face Fontan failure, defined as circulatory dysfunction with limited functional capacity (New York Heart Association [NYHA] class III or IV), Fontan takedown or conversion, the development of debilitating complications including protein-losing enteropathy (PLE) and plastic bronchitis, the need for cardiac transplantation, or death (Fig 73.5).13,14 FIG 73.5 Freedom from failure (death, heart transplantation, reoperation, or poor functional status) for patients with and without hypoplastic left heart syndrome (HLHS) as reported by the Australia and New Zealand Fontan Registry LV, Left ventricle; RV, right ventricle (From D'udekem Y, Iyengar AJ, Galati JC, et al Redefining expectations of long-term survival after the fontan procedure: twenty-five years of follow-up from the entire population of Australia and New Zealand Circulation 2014;130[suppl 1]:S32–S38.)