Fontan procedure
Fontan procedure | |
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Uses | Palliative surgery for child with univentricular heart |
The Fontan procedure or Fontan–Kreutzer procedure is a
Indications
The Fontan Kreutzer procedure is used in pediatric patients who possess only a single functional ventricle, either due to lack of a heart valve (e.g.
Types
There are four variations of the Fontan procedure:[7]
- Ventricularization of the Right Atrium (The original Fontan's Technique)
- Atriopulmonary connection (the original Kreutzer's Technique)
- Intracardiac total cavopulmonary connection (lateral tunnel) (described by Marc De Leval and Aldo Castañeda, separately)
- Extracardiac total cavopulmonary connection (described by Carlo Marceletti and Francisco Puga for Heterotaxy Syndrome)
Approach
The Fontan procedure is the third procedure in the staged surgical palliation.[8] It is performed in children born with congenital heart disease without two functional ventricles and an effective parallel blood flow circuit.[9]
The first stage is known as the Norwood procedure. This stage generally involves combining the pulmonary artery and aorta to form a larger vessel for blood to get to the body. An artificial tube or shunt can be placed from this larger vessel to the pulmonary arteries so that blood can get from the heart to the lungs. The wall between the left and right atrium can be removed to allow the mixing of oxygenated and de-oxygenated blood.[10][11][12]
The second stage is called the hemi-Fontan or the
The third stage is called the Fontan procedure which involves redirecting the blood from the inferior vena cava to the lungs.[8] At this point, the oxygen-poor blood from upper and lower body flows through the lungs without being pumped (driven only by the pressure that builds up in the veins or central venous pressure). This improves the lower than normal oxygen levels and results in one functional ventricle that is responsible for supplying blood to the rest of the body. There are currently three various modern techniques for the Fontan procedure which include: Atriopulmonary connection, lateral tunnel total cavopulmonary connection, and extracardiac conduit.
Contraindications
After Fontan Kreutzer completion, blood must flow through the lungs without being pumped by the heart. Therefore, children with high
Post-operative complications
In the short term, children can have trouble with
In a 2016 review, Dr. Jack Rychik, head of the Single Ventricle Survivorship Program at
Because of structural and electrochemical changes related to scarring after the procedure, arrhythmias are common. Pacemakers are placed in as many as 7% of patients who undergo the Fontan procedure.[18] While the need for pacemakers may be related to the underlying cardiac anomaly, there is sufficient evidence that the surgery itself lead to the need for cardiac pacing.
The Fontan procedure is palliative — not curative — but more than 80% of the cases can result in normal or near-normal growth, development, exercise tolerance, and good quality of life.[19] However, 10% or more of patients may eventually require heart transplantation,[20] and given the long-term consequences of chronic venous hypertension and insidious organ damage, freedom from morbidity is unlikely in the long term. New approaches to the management of failing Fontans or other clinical deterioration have included lymphatic decompression surgical procedures & intervention, Ventricular assist devices or other mechanical support therapies as either bridge to transplantation or destination therapies.[21]
Renal complications may occur. This is attributed to the circulatory changes in blood flow as well as possible exposure to nephrotoxic medications, iodine contrast agents, and long term cyanotic and ischemic nephropathy. Abnormalities including chronic kidney disease and impaired renal function have been shown with measured renal function.[22] Popular markers, such as proteinuria and microalbuminuria, are used in the measurement renal function.
It is estimated in 2018 there was an 85% for a survival rate of thirty years following a Fontan procedure and there are approximately 50,000 to 70,000 people in the world with Fontan circulation.[23] It is approximated that 40% of people with Fontan circulation are ≥18 years of age.[22]
Fontan circulation
A normal heart system has a series circuit with the right ventricle pumping blood into the pulmonary circulation which, after exchanging gases, delivers it to the left ventricle (and systemic arteries) through pulmonary veins. Because of this series arrangement blood flow (cardiac output) is the same in pulmonary and systemic circulations, as electrical current is the same across series resistances. In a Fontan Circulation, the right ventricle does not exist (or is bypassed) and the venae cavae are attached directly to the pulmonary artery.[24] After oxygenation, the blood is pumped in systemic arteries (aorta) by the unique ventricle. Because of the missing right ventricle, the force driving blood through the lung is strongly reduced, thus causing engorgement of the venous circulation, the most frequent complication of the Fontan procedure.
Pregnancy considerations
The Fontan circulation can influence the
History
The Fontan procedure was initially described in 1971 by
References
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External links
- Media related to Fontan procedure at Wikimedia Commons