LAUSR

The Fontan procedure is considered the treatment of choice for patients with a univentricular heart defect for whom biventricular repair is not possible. The Fontan procedure entails the surgical rerouting of the systemic venous return directly to the pulmonary arteries and thereby renouncing a subpulmonary ventricle. This results in a restored balance between pulmonary and systemic blood flow, maintaining oxygenation and perfusion. However, due to the absence of a subpulmonary ventricle, the Fontan circulation is characterized by a paradoxal chronically increased systemic venous pressure and non-pulsatile pulmonary blood flow. Furthermore, the single ventricle needs to drive the cardiac output through both the systemic and pulmonary vascular beds. Short-term outcomes of the Fontan procedure have been considered successful. However, long-term outcomes are characterized by an impaired functional clinical status with gradual attrition of the Fontan circulation over time.1 Eventually this may lead to a ‘Fontan failure’ syndrome. Although not uniformly defined, symptoms of this syndrome include arrhythmia, thromboembolic events, ventricular dysfunction, pulmonary vascular disease, lymphatic dysfunction, protein-losing enteropathy, plastic bronchitis and Fontan-associated liver disease (FALD). Traditionally, a failing Fontan has been haemodynamically stereotyped by a low cardiac index (CI), high central venous pressure (CVP) and elevated pulmonary vascular resistance index (PVRi).2 Remarkably, ventricular function can be relatively preserved and is therefore considered not to be a hallmark of Fontan failure.3 Over the last decades, Fontan failure has become a major issue since the Fontan population is growing into adulthood due to an increased life expectancy.