*4.1.5 Address other defects during Stage I*

In patients with inter-atrial obstruction, it should be relieved either by transcatheter methodology or by surgery as deemed appropriate for a given clinical scenario. If there is associated coarctation of the aorta, it should also be relieved. Some patients with double-inlet left ventricle may have significant obstruction at the level of bulboventricular foramen [61]. Similarly some babies with tricuspid

### **Figure 2.**

*Stage I Fontan for hypoplastic left heart syndrome. Selected frames from cineangiograms demonstrating Norwood operation in which the neoaorta (NAo) and hypoplastic aorta (HAo) perfuse the coronary arteries (CAs) as shown in (a), Blalock-Taussig (BT) shunt as illustrated in (b) and Sano shunt as depicted in (c). (b) and (c) are from two different babies. LPA, left pulmonary artery; RPA, right pulmonary artery (Reproduced from [30]).*

atresia with transposition of the great arteries may have obstruction at the VSD level, causing obstruction to systemic blood flow [61, 62]. Such babies require Damus-Kaye-Stansel (connection of the aorta to the PA) [63] along with a BT shunt. Inter-atrial obstruction may be present frequently in babies with mitral atresia and single ventricle [64]. In such babies, predictable fall in PVR occurs following balloon or surgical relief of inter-atrial obstruction [64]; consequently, PA banding should be undertaken without hesitation at the time of relieving the atrial septal obstruction, so as to reduce the probability for CHF, lower the PVR and PA pressure, prevent pulmonary vascular obstructive disease (PVOD), and pave the way for Fontan approach [64].

### **4.2 Stage II**

Irrespective of the type of palliative surgery in the neonatal period, bidirectional Glenn procedure [12–14, 17, 23], namely, anastomosis of the SVC to the right PA, end-to-side (**Figure 3**) is performed around the age of 6 months. The previously performed BT or Sano shunt is ligated at the same time. Although performing the procedure at 6 months is generally adopted, it can be performed as early as 3 months provided normalcy of PA pressure and anatomy can be documented.

**135**

**Figure 4.**

**Figure 3.**

*(Reproduced from [30]).*

*Fontan Operation: A Comprehensive Review DOI: http://dx.doi.org/10.5772/intechopen.92591*

In patients with persistent left SVC, bilateral bidirectional Glenn (**Figure 4**) is undertaken especially in patients with a small or absent left innominate vein. A bidirectional Glenn procedure may also be performed for patients with infrahepatic

interruption of the IVC with azygos or hemiazygos continuation, and such a

Prior to the bidirectional Glenn procedure, normal PA pressures and adequate size of the branch PAs should be ensured by cardiac catheterization and

*Stage II of Fontan. Selected frames from cineangiograms in two different children illustrating bidirectional Glenn operation in which the superior vena cava is anastomosed to the right pulmonary artery (RPA). Unobstructed flow from the SVC to the right (RPA) and left (LPA) pulmonary arteries is clearly seen.* 

*Stage II Fontan. Selected frames from cineangiograms in a different child than shown in Figure 3, illustrating bilateral bidirectional Glenn operation. (a) Superior vena caval angiogram demonstrates immediate visualization of the right pulmonary artery (RPA). Un-opacified blood flow from persistent left SVC (PLSVC) is indicated by the arrow in (a). (b) PLSVC angiogram illustrates rapid opacification of the left pulmonary artery (LPA). Un-opacified blood from the right SVC is shown by the arrow in (b). Flow from the* 

*respective SVCs into the pulmonary arteries is clearly seen (Reproduced from [30]).*

procedure is called a Kawashima procedure by some authorities.
