3 STAGE CONCEPT for single ventricle: BT shunt/Glenn shunt/Fontan operation
The aortopulmonary shunt (Blalock-Taussig shunt, BT shunt) is performed in the first weeks of life. A Gore Tex tube of the appropriate size (usually 3.5 mm) is inserted between the pulmonary artery and a branch of the aorta.
The next step usually takes place at the age of 4 months, with a body weight of 5kg. During the so-called Glenn operation, the superior vena cava is attached to the right pulmonary artery and all the venous blood from the upper half of the body is channelled directly into the lungs. This is known as a bidirectional Glenn anastomosis. The superior vena cava is separated from the right atrium via a median sternotomy after the heart-lung machine is attached to the beating heart (normothermic circulatory situation). After mobilisation of the pulmonary artery, this is widely anastomosed to it. The residual stump on the atrial side is sutured over.
In hemifontaneous surgery, the stump on the atrial side of the superior vena cava is not cut after incision and is not sutured over. The superior vena cava is left in its continuity and a Goretex membrane is sutured from the right atrium into the right pulmonary artery and thus the blood is channelled directly into the pulmonary artery.
The final step of this concept is the FONTAN operation. This operation (total cavopulmonary anastomosis TCPC) can be performed in different ways: extracardiac tunnel, intracardiac tunnel, intra-extracardiac tunnel.
In extracardiac Fontan surgery, the inferior vena cava is removed from the right atrium via a median sternotomy after the heart-lung machine is attached to the beating heart (in a normothermic circulatory situation), and a Goretex prosthesis is used to create a connection between the inferior vena cava and the lower side of the pulmonary artery. The stump at the atrium is sutured over. A small window is usually created between the prosthesis and the right atrium in order to better tolerate the immediate change in circulation. This window is then closed by means of a cardiac catheter. The result of this operation enables complete circulatory separation. All venous blood is now channelled directly into the lungs.
During the intracardiac Fontan operation, a tunnel is drawn through the right atrium and the blood is channelled directly from the lower half of the body into the lungs.
Fontan surgery is usually performed between the ages of 2 and 4.