**2. The Fontan patient**

### **2.1 Staged palliation**

First stage: The goals of initial palliation are to provide unobstructed systemic blood flow, well-balanced pulmonary and systemic circulations with controlled pulmonary blood flow, and unobstructed pulmonary and systemic venous return (including unrestricted atrial level mixing of venous returns). The elevated pulmonary vascular resistance (PVR) characteristic of the newborn period requires a staged approach to achieve these long-term goals that include normalization of the ventricular volume load and provision of normal systemic oxygen delivery. The success of a shunt is evaluated based on the relief of cyanosis, without a significant volume overload of the ventricle, and the induction of pulmonary growth without causing major changes to PVR. The systemic to pulmonary shunt is designed to last 4–6 months, sufficient time for the PVR to drop, allowing a partial cavopulmonary connection to be created safely (**Figure 1**).

Second stage: The superior cavopulmonary connection (SCPC, bidirectional Glenn or hemi-Fontan) is the surgical anastomosis of the superior vena cava (SVC) to the pulmonary artery (PA) and has a significant benefit on cardiac function. The secondstage procedure diminish the volume load on the SV while maintaining systemic oxygen delivery. Therefore, the ventricular work-load approximates that of the systemic ventricle in a biventricular circulation. One of the critical features of the second-stage procedure is the opportunity for the ventricle to have enough time for remodeling following the removal of the volume load prior to Fontan completion (**Figure 2**). In addition, this stage provides the opportunity to address other anatomic and physiologic abnormalities (including atrioventricular valve regurgitation, PA distortion) in the same surgery, optimizing the chances of a successful Fontan completion later on [4].

Third stage: In 1971, Francis Fontan and colleagues described a surgical technique for successful palliation of patients with tricuspid atresia [3]. Subsequently, this technique has been applied to treat most forms of functional SV. Typically, 1–3 years after the second stage, the inferior vena cava (IVC) is connected surgically to the PA to complete the Fontan procedure [5].

There are three different types of Fontan palliation:

• The atriopulmonary connection (APC) consists of the right atrium connected directly to the PA. Although this surgical reconstruction is not performed

**107**

**Figure 2.**

*repair.*

**Figure 1.**

*Physiopathological Approach of the Fontan Patient for Noncardiac Surgery for the Anesthesiologist*

*Changes in PVR according to time and the appropriate age for performing stage palliation until completing the Fontan procedure for complex congenital heart disease that does not qualify for biventricular repair (PVR,* 

in modern practice, patients with APCs are presenting to the perioperative setting as adults. The Fontan procedure has been considerably modified since the description of a direct APC by Fontan. Several modifications were subsequently proposed in an effort to improve hemodynamic function and

*Changes in the preload according to time and the appropriate age for performing stage palliation until completing the Fontan procedure for complex congenital heart disease that does not qualify for biventricular* 

• The intracardiac total cavopulmonary connection, or lateral tunnel, consists of a SVC surgically connected directly to the right PA. IVC traverses through the

counteract progressive atrial dilation [6].

*pulmonary vascular resistance; SVR, systemic vascular resistance).*

atrium via a baffle directly to the PA.

*DOI: http://dx.doi.org/10.5772/intechopen.93388*

*Physiopathological Approach of the Fontan Patient for Noncardiac Surgery for the Anesthesiologist DOI: http://dx.doi.org/10.5772/intechopen.93388*

### **Figure 1.**

*Advances in Complex Valvular Disease*

some forms of heterotaxy syndrome [5].

**2. The Fontan patient**

**2.1 Staged palliation**

patients with the unique Fontan physiology.

to the PA to complete the Fontan procedure [5].

There are three different types of Fontan palliation:

• The atriopulmonary connection (APC) consists of the right atrium connected directly to the PA. Although this surgical reconstruction is not performed

ventricle. This single ventricle (SV) has to maintain both the systemic and the pulmonary circulations, which at birth are not connected in series but in parallel [2]. Regardless of the exact nature of the connections, the completed circulation is often described as one having a single energy source, the systemic ventricle [3]. The survival improvement of patients with univentricular physiology is due to the development of the staged palliation approach for complex congenital heart lesions not suitable for biventricular repair. The final Fontan stage results in the conversion of a parallel circulation, to a pulmonary and systemic circulation that is in series regardless of the underlying cardiac anatomy [2, 4]. Such lesions include hypoplastic left-heart syndrome (HLHS), tricuspid atresia, unbalanced atrioventricular septal defects, double-inlet left ventricle, double-outlet right ventricle, and

The objective of this chapter is to provide anesthesiologists the conceptual aspects applicable to the preoperative evaluation and perioperative management of

First stage: The goals of initial palliation are to provide unobstructed systemic blood flow, well-balanced pulmonary and systemic circulations with controlled pulmonary blood flow, and unobstructed pulmonary and systemic venous return (including unrestricted atrial level mixing of venous returns). The elevated pulmonary vascular resistance (PVR) characteristic of the newborn period requires a staged approach to achieve these long-term goals that include normalization of the ventricular volume load and provision of normal systemic oxygen delivery. The success of a shunt is evaluated based on the relief of cyanosis, without a significant volume overload of the ventricle, and the induction of pulmonary growth without causing major changes to PVR. The systemic to pulmonary shunt is designed to last 4–6 months, sufficient time for the PVR to drop, allowing a partial cavopulmonary connection to be created safely (**Figure 1**). Second stage: The superior cavopulmonary connection (SCPC, bidirectional Glenn or hemi-Fontan) is the surgical anastomosis of the superior vena cava (SVC) to the pulmonary artery (PA) and has a significant benefit on cardiac function. The secondstage procedure diminish the volume load on the SV while maintaining systemic oxygen delivery. Therefore, the ventricular work-load approximates that of the systemic ventricle in a biventricular circulation. One of the critical features of the second-stage procedure is the opportunity for the ventricle to have enough time for remodeling following the removal of the volume load prior to Fontan completion (**Figure 2**). In addition, this stage provides the opportunity to address other anatomic and physiologic abnormalities (including atrioventricular valve regurgitation, PA distortion) in the same surgery, optimizing the chances of a successful Fontan completion later on [4]. Third stage: In 1971, Francis Fontan and colleagues described a surgical technique for successful palliation of patients with tricuspid atresia [3]. Subsequently, this technique has been applied to treat most forms of functional SV. Typically, 1–3 years after the second stage, the inferior vena cava (IVC) is connected surgically

**106**

*Changes in PVR according to time and the appropriate age for performing stage palliation until completing the Fontan procedure for complex congenital heart disease that does not qualify for biventricular repair (PVR, pulmonary vascular resistance; SVR, systemic vascular resistance).*

### **Figure 2.**

*Changes in the preload according to time and the appropriate age for performing stage palliation until completing the Fontan procedure for complex congenital heart disease that does not qualify for biventricular repair.*

in modern practice, patients with APCs are presenting to the perioperative setting as adults. The Fontan procedure has been considerably modified since the description of a direct APC by Fontan. Several modifications were subsequently proposed in an effort to improve hemodynamic function and counteract progressive atrial dilation [6].

• The intracardiac total cavopulmonary connection, or lateral tunnel, consists of a SVC surgically connected directly to the right PA. IVC traverses through the atrium via a baffle directly to the PA.

• The extracardiac cavopulmonary connection also consists of a direct anastomosis of the SVC to the PA. However, an extracardiac conduit is used to route IVC blood directly to the PA without traversing the right atrium [5, 7].

Initially, adult survivors were mainly APC Fontan patients, but increasing numbers of both forms of TCPC Fontan patients now survive to adult life [7]. The extracardiac cavopulmonary connection is the main method employed currently in surgical centers.
