Management of the failing Fontan circulation

The ‘Fontan circulation’ has evolved to include a variety of surgical procedures designed to overcome the absence of two distinct ventricular chambers. w1ew3 Inherent to this circulation is chronic elevation of right atrial and vena caval pressure, and absence of a dedicated power source to serve the pulmonary circulation, making low pulmonary vascular resistance and optimal systemic ventricular function the essential ingredients of a successful Fontan circulation. Originally designed for the single left ventricle, modifications to the original atriopulmonary connections extended repairs to complex ventricular anatomy, and are now most commonly performed for single right ventricular anatomy associated with hypoplastic left heart syndrome. Together with improved perioperative management, creation of the Fontan circulation in two stages (superior cavopulmonary anastomosis followed by later Fontan completion), and performance of Fontan procedures at a younger age, have led to reduced operative mortality associated with the Fontan procedure of #5% (compared with 15e30% in earlier decades); survival at 20 years is presently 85%. w5 Over the last two decades, the initial survivors of the atriopulmonary Fontan repairs have reached adulthood, bringing a multiplicity of haemodynamic complications and sequelae of their abnormal circulatory status. The atriopulmonary connection is now obsolete as a surgical option, and the current surviving adults with this circulation do not reflect contemporary Fontan outcomes. Nonetheless, their attendant compendium of complications and sequelae provides a daunting array of management challenges, and stigmatises the current perception of long term Fontan outcomes. The ‘Fontan circulation’ now encompasses a spectrum of anatomic substrates, staging options, and operative techniques. Problems classified as ‘Fontan failure’may represent problems inherent to the morphologic substrate, operative variables, and inevitable sequelae of the Fontan circulation: chronic venous congestion and progressively declining functional status. This review will separate complications into those where intervention may optimise clinical status while maintaining the Fontan circulationdthe ‘failing Fontan’dand those conditions which have progressed to a ‘failed Fontan’, where options are limited to cardiac transplantation or attempts to minimise the impact of irreversible functional deterioration. Finally, we will discuss strategies which may alter the incidence and time course of Fontan failure.