The failing Fontan

Abstract

Nearly 50 years back, Francis Fontan pioneered an operation for tricuspid atresia that bears his name today. The operation has since undergone numerous modifications and continues to be widely applied to an array of single ventricles. Despite restoring normal oxygen levels in the body, the operation creates a neoportal system where adequate cardiac output can be generated only at the expense of increased systemic venous congestion. This results in slow but relentless damage to the end organ systems especially the liver. Continuous surveillance of the patient to monitor this circulation, that will ultimately fail, is of paramount importance. Timely medical and cardiac catheterization and surgical intervention can extend the life span of Fontan patients. Ultimately a change of the hemodynamic circuit in the form of heart transplantation or ventricular assist device will be required to salvage the failing Fontan circuit.

Keywords: Complications; Failure; Fontan; Operation.

Fig. 1

Comparison of normal and Fontan circulations. Normal circulation consists of systemic(S) and pulmonary (P) circulations connected in series with an intervening right ventricle (RV). The right ventricle maintains the right atrial (RA) pressure or the central venous pressure marginally lower than the left atrial (LA) pressure. In a Fontan circulation, the right atrial pressure is elevated markedly to provide the push into the pulmonary system. LV: left ventricle, Ao: aorta, PA: pulmonary artery, SV: single ventricle

Fig. 2

Figure depicting a left ventricular assist device (such as the HeartMate3 or HVAD) in a failing Fontan circulation when the primary problem is systemic ventricular dysfunction (Fig. 2a) versus a subpulmonary device (such as viscous impeller design) when the ventricular function is preserved (Fig. 2b)