Fontan's operation

The original execution of Fontan's surgery for a tricuspid atresia

The Fontan operation is today (2004) as the most common palliative surgery for complex congenital heart defects carried out, dealing with a double inlet left ventricle ( Einkammerherz group). Initially used primarily for tricuspid atresia , there are now a number of modifications to other forms of the single-chamber heart. The original one-step surgical technique has also been further developed and is now usually performed in two surgical steps.
The surgical procedure is indicated when

• the heart has only one functionally effective ventricle
• arterial and venous blood mix in this chamber
• the common chamber feeds both the body and pulmonary circulation

and has the goal of transforming the previously parallel and common circuit (with a high volume load on the ventricle ) into two separate circuits connected in series.

The operation is named after its developer, the French heart surgeon François MF Fontan (1929-2018), who worked in Bordeaux .

Surgical steps

1. Glenn anastomosis

All congenital or surgically created central inflows to the pulmonary arteries are interrupted. This is usually the division of the pulmonary trunk (as its main trunk ), the closure of an existing ductus arteriosus and the closure of previously created aorto-pulmonary shunts . The superior vena cava is divided and connected to the right pulmonary artery (pulmonary artery). The part close to the heart is blindly closed. The inferior vena cava directs its blood unchanged into the main chamber. As a result, cyanosis persists , but less than before the operation.

2. Fontan completion = total cavo-pulmonary anastomosis (total cavo-pulmonary connection = TCPC)

The blood of the inferior vena cava is also conducted to the pulmonary artery via a plastic prosthesis ( GoreTex patch ) through ( intracardially ) the right atrium ( atrium ); A connection is created from below so that the blood from the inferior vena cava is now also conducted directly into the pulmonary vascular system. A small hole is punched ( fenestration ) in this patch, which separates the flowing venous (low-oxygen) blood from the functionless right atrium ( this is connected to the left atrium by removing the remaining remnants of the atrial septum (septum atriale)) The overflow valve is used for the first time if the lungs cannot yet absorb all of the blood from the body's circulation. This hole may close by itself or be closed during a cardiac catheterization session when it is no longer necessary for cardiovascular function.

Instead of the intracardiac prosthesis, an extracardiac type of operation is used today, in which the blood is diverted from the inferior vena cava via a half-shell sewn onto the right atrium ( extracardiac shunt ). The extracardiac Fontan operation using a vascular prosthesis made of Gore-Tex as a connection between the inferior vena cava and the pulmonary artery is well suited for children with good hemodynamics. In contrast to the Glenn anastomosis with the intracardial shunt, the extracardiac shunt can be placed without the aid of the heart-lung machine , since the heart cavities do not have to be opened.

Postoperative condition

Arterial and venous blood flow are now separated. After the TCPC (in contrast to the Glenn anastomosis, where arterial and venous blood from the lower part of the body still mix) there is no longer any cyanosis . By diverting the venous blood from the body circulation without a functionally effective right ventricle directly into the pulmonary circulation, the body and pulmonary circulation are pumped one after the other. The pressure from the body's circulation is sufficient to pump the pulmonary circulation. This is possible if the pulmonary vascular resistance is not too high. Therefore, this operation is not possible in patients who have developed pulmonary hypertension or who have too high a pulmonary vascular resistance .

variants

Fontan-Björk

In patients with a hypotonic but functional right ventricle, the Fontan-Björk approach is also operated on (so-called 3/4 heart). This creates a flapless connection between the right atrium and the right ventricle, which partially consists of the body's own tissue - that is, it can grow with it. The advantage of this Fontan variant is that the right ventricle is also used in the circulatory system. This stimulates the right ventricle, which, although weak, still helps blood flow to the lungs.

Long-term expectations

The children usually develop well after this surgery. Regular check-ups are indicated for life, as is endocarditis prophylaxis .

These types of surgery have been carried out in Germany since the late 1980s, and increasingly so in the late 20th century. It is therefore not possible to fall back on long-term experience up to now.

literature

• Ernst W. Keck, Gerd Hausdorf (ed.): Pediatric cardiology . 5th edition. Urban & Fischer, 2002, ISBN 978-3-437-21960-3 , 488 pages ( books.google.de )

Web links

• Fontan information with illustrations
• Dissertation with description of OP modifications (p. 15 ff., PDF)

Individual evidence

1. ↑ Reinhard Larsen: Anesthesia and intensive medicine in cardiac, thoracic and vascular surgery. (1st edition 1986) 5th edition. Springer, Berlin / Heidelberg / New York a. a. 1999, ISBN 3-540-65024-5 , p. 344.
2. ↑ W. Kuroczynski, D. Senft, A. Elsaesser, C. Kampmann: intra- or extra-cardiac Fontan surgery? A simple strategy when to do what. In: Archives of Medical Science. Volume 10, number 4, August 2014, pp. 706-710, doi: 10.5114 / aoms.2013.33432 , PMID 25276154 , PMC 4175755 (free full text).

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