**4.3 Stage III**

During the final Stage III, the IVC flow is diverted into the PA along with creation of a fenestration. We arbitrarily divided [30] these procedures into Stage IIIA (diversion of IVC into the PA) and Stage IIIB (closure of the fenestration).

## *4.3.1 Stage IIIA*

In the final Stage III, the total cavopulmonary connection is achieved by diverting the IVC flow into the PA either by a lateral tunnel [18, 65] or by an extra-cardiac, non-valved conduit (**Figures 5** and **6**) [21, 22]; the procedure is usually performed between the ages of 1 and 2 years, usually 1 year following the bidirectional Glenn procedure. Most surgeons seem to prefer extra-cardiac conduit to accomplish this final stage of Fontan. The majority of surgeons construct a fenestration, 4–6 mm in size, between the conduit and the atria (**Figures 5** and **6**) [27]. While the creation of fenestration during the Fontan operation was initially proposed for high-risk patients [27, 28], most surgeons now seem to prefer fenestration, since fenestration during the Fontan improves mortality rate and reduces morbidity during the immediate postoperative period [30].

Cardiac catheterization and selective cineangiography are usually performed shortly prior to Fontan conversion in order to assess the PA anatomy and pressures, trans-pulmonary gradient, PVR, and ventricular end-diastolic pressure and

### **Figure 5.**

*Selected cine frames in posteroanterior (a) and lateral (b) views, demonstrating Stage IIIA Fontan procedure diverting the inferior vena caval flow into the pulmonary arteries via a non-valve conduit (Cond). Flow across the fenestration (fen) is shown by arrows in (a) and (b). HV, hepatic veins; LPA, left pulmonary artery; PG, pigtail catheter in the descending aorta; RPA, right pulmonary artery.*

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

to assure that they are normal prior to proceeding with Fontan completion. At some institutions, MRI is used for this assessment instead of catheterization and angiography; however, the author's preference is catheterization. During this catheterization, any significant collateral vessels that are present are also

*Selected cine frames in posteroanterior (a) and lateral (b) views in a different patient to the one shown in Figure 5, demonstrating Stage IIIA Fontan procedure diverting the inferior vena caval (IVC) flow into the pulmonary arteries via a non-valve conduit (Cond). Flow across the fenestration (fen) is shown by arrows in* 

In the final stage, Stage IIIB, the fenestration is closed (**Figures 7b**, **8b**, and **9B** and **C**) by transcatheter methodology [27, 30–35], usually 6–12 months after Fontan Stage, IIIA. In the past, most devices used to occlude ASDs [32–35] were employed for this purpose, but at the present time, Amplatzer septal occluders are the most commonly used devices to accomplish such closures. If there are any other

In children who have one functioning ventricle requiring Fontan correction, the systemic and pulmonary circulations work in-parallel in place of the usual in-series circulation. A fragile equilibrium between the two circulations must be preserved so that adequate systemic and pulmonary perfusions are maintained. There is substantial interstage mortality ranging from 5 to 15% [66–68] which may be due to restrictive atrial communication, obstruction of the aortic arch, blockage of the shunt, distortion

residual shunts, they should also be occluded (**Figure 10**) by device closure.

of the PAs, atrioventricular valve insufficiency, or a combination thereof [66]. Intercurrent illnesses such as dehydration, respiratory tract illness, or fever disturb this balance and make the patients to become critically ill and have been blamed for interstage mortality [66, 68]. The surgically created BT and Sano shunts may also get thrombosed producing severe hypoxemia [69]. Indeed, these abnormalities produce significant interstage mortality [67]; these appear to occur more frequently between Stages I and II than between Stages II and III. Consequently, extreme vigilance in managing these patients should be maintained by the caregiver [68, 70]; even trivial

illnesses must be aggressively monitored and addressed as appropriate.

transcatheter-occluded by most cardiologists.

*(a) and (b). Abbreviations are the same as those in Figure 5.*

*4.3.2 Stage IIIB*

**Figure 6.**

**4.4 Interstage problems**

### **Figure 6.**

*Advances in Complex Valvular Disease*

the time of this operation.

immediate postoperative period [30].

**4.3 Stage III**

*4.3.1 Stage IIIA*

cineangiography. Echo-Doppler or other imaging studies (magnetic resonance imaging [MRI] or computed tomography [CT]) is advocated at some institutions. If PA stenosis is present, it may be addressed with balloon angioplasty or stent implantation, as deemed appropriate, or it may be addressed during the bidirectional Glenn procedure. Atrioventricular valve regurgitation, aortic coarctation, subaortic obstruction, and other abnormalities should also be repaired/addressed at

During the final Stage III, the IVC flow is diverted into the PA along with creation of a fenestration. We arbitrarily divided [30] these procedures into Stage IIIA

In the final Stage III, the total cavopulmonary connection is achieved by diverting the IVC flow into the PA either by a lateral tunnel [18, 65] or by an extra-cardiac, non-valved conduit (**Figures 5** and **6**) [21, 22]; the procedure is usually performed between the ages of 1 and 2 years, usually 1 year following the bidirectional Glenn procedure. Most surgeons seem to prefer extra-cardiac conduit to accomplish this final stage of Fontan. The majority of surgeons construct a fenestration, 4–6 mm in size, between the conduit and the atria (**Figures 5** and **6**) [27]. While the creation of fenestration during the Fontan operation was initially proposed for high-risk patients [27, 28], most surgeons now seem to prefer fenestration, since fenestration during the Fontan improves mortality rate and reduces morbidity during the

Cardiac catheterization and selective cineangiography are usually performed shortly prior to Fontan conversion in order to assess the PA anatomy and pressures, trans-pulmonary gradient, PVR, and ventricular end-diastolic pressure and

*Selected cine frames in posteroanterior (a) and lateral (b) views, demonstrating Stage IIIA Fontan procedure diverting the inferior vena caval flow into the pulmonary arteries via a non-valve conduit (Cond). Flow across the fenestration (fen) is shown by arrows in (a) and (b). HV, hepatic veins; LPA, left pulmonary artery; PG,* 

*pigtail catheter in the descending aorta; RPA, right pulmonary artery.*

(diversion of IVC into the PA) and Stage IIIB (closure of the fenestration).

**136**

**Figure 5.**

*Selected cine frames in posteroanterior (a) and lateral (b) views in a different patient to the one shown in Figure 5, demonstrating Stage IIIA Fontan procedure diverting the inferior vena caval (IVC) flow into the pulmonary arteries via a non-valve conduit (Cond). Flow across the fenestration (fen) is shown by arrows in (a) and (b). Abbreviations are the same as those in Figure 5.*

to assure that they are normal prior to proceeding with Fontan completion. At some institutions, MRI is used for this assessment instead of catheterization and angiography; however, the author's preference is catheterization. During this catheterization, any significant collateral vessels that are present are also transcatheter-occluded by most cardiologists.
