Post Fontan State

Post Fontan state

Original Fontan repair was an atriopulmonary connection. But now the term Fontan repair has almost become a generic term for single ventricular type of repair. It is used for a wide range of conditions like tricuspid atresia or any other form of right sided hypoplasia or atresia, double inlet left ventricle, hypoplastic left heart and some variations of double outlet right ventricle. It is a staged procedure aimed at routing systemic venous return directly to the pulmonary artery bypassing the ventricle. Initially a systemic to pulmonary shunt is done to stabilize the pulmonary blood flow.

This is in the form of a bidirectional Glenn procedure. Superior vena is connected to the right pulmonary artery by an end to side anastomosis to provide blood flow to both pulmonary arteries. Finally the inferior vena caval blood is directed to the pulmonary artery by an intracardiac right atrial or extra cardiac route.

Arrhythmias are an important sequelae of post Fontan state in the long run. Most patients develop sick sinus syndrome or the tachycardia-bradycardia syndrome. Heart failure is another important complication in the post Fontan state. Right atrium may become enlarged and a source for thrombus formation. This can be tackled by revision of the Fontan circuit to bypass the right atrium by an extra cardiac circuit. Protein losing enteropathy is still another important troublesome sequelae in the post Fontan state with elevated systemic venous pressures. This may be relieved by baffle fenestrations to relieve the systemic venous congestion, though at the expense of systemic desaturation.

Reports have suggested that oral sildenafil may have a role in the treatment of protein losing enteropathy. Sildenafil causes pulmonary vasodilatation and improves ventricular filling and cardiac output [1]. It is also thought to have a direct effect on the mesenteric vascular resistance [2].

References

  1. Rychik J. Protein-Losing Enteropathy after Fontan Operation. Congenit Heart Dis. 2007;2:288-300.
  2. Uzun O, Wong JK, Bhole V, Stumper O. Resolution of protein-losing enteropathy and normalization of mesenteric Doppler flow with sildenafil after Fontan. Ann Thorac Surg. 2006;82:e39–e40.