Fontan procedure
Fontan procedure is a palliative surgical procedure used in children with univentricular hearts that results in the flow of systemic venous blood to the lungs without passing through a ventricle.
Some facts about Fontan procedure:
- Several complex congenital heart abnormalities including tricuspid atresia, pulmonary atresia with intact ventricular septum, hypoplastic left heart syndrome, and double-inlet ventricle can be treated by Fontan procedure.
- Direct anastomosis of the right atrium to the main pulmonary artery is included the original Fontan procedure
- However, multiple modifications have been employed later on.
- Exercise intolerance, right atrium dilatation and arrhythmia, ventricular failure, systemic and hepatic venous hypertension, portal hypertension, coagulopathy, pulmonary arteriovenous malformation, venovenous shunts, and lymphatic dysfunction are complications of Fontan circulation.
- The systemic and pulmonary circulations are placed in series with the functional single ventricle as the venous blood is diverted from the inferior vena cava (IVC) and superior vena cava (SVC) to the pulmonary arteries without passing through the morphologic right ventricle.
- The Fontan procedure is done in pediatric patients who have only a single functional ventricle, either due to lack of a heart valve, for example tricuspid or mitral atresia, an abnormality of the pumping ability of the heart such as hypoplastic left heart syndrome or hypoplastic right heart syndrome, or a complex congenital heart disease where a bi-ventricular repair is impossible or inadvisable.
- Blood is allowed to be delivered to the lungs through central venous pressure rather than via the right ventricle by this surgery.
- Usually, Fontan completion is carried out when the patient is 2 to 5 years of age, but is also performed before 2 years of age
- Magnetic resonance imaging is the best option for postoperative evaluation of patients who underwent the Fontan procedure
Types of Fontan procedure:
There are four variations of the Fontan procedure including:
- Ventricularization of the Right Atrium which is the original Fontan's Technique.
- Atriopulmonary connection which is the original Kreutzer's Technique.
- Intracardiac total cavopulmonary connection also known as lateral tunnel, described by Marc De Leval and Aldo Castaneda, separately.
- Extracardiac total cavopulmonary connection, described by Carlo Marceletti
Approach for Fontan procedure:
- Usually the procedure done as a two staged repair.
- Oxygen-poor blood is redirected from the top of the body to the lungs in the first stage, also called a Bidirectional Glenn procedure or Hemi-Fontan.
- The pulmonary arteries are disconnected from their existing blood supply.
- The superior vena cava (SVC), by which blood returning from the upper body is carried, will be disconnected from the heart and instead will be redirected into the pulmonary arteries.
- The inferior vena cava (IVC), by which blood returning from the lower body is carried will continues to connect to the heart.
- The blood from the IVC is redirected to the lungs in the second stage, also called Fontan Kreutzer completion.
- The oxygen-poor blood from upper and lower body flows through the lungs without being pumped and driven only by the pressure that builds up in the veins at this stage.
- The hypoxia will be corrected by this leaving the single ventricle responsible only for supplying blood to the body.
