**5.1 Immediate results**

The results of original Fontan [1, 2] and its earlier modifications, namely, RA-to-PA or RA-to-RV anastomosis either directly or via valved or non-valved conduits, revealed high initial mortality rates. The initial mortality rates ranged from 10 to 26% [9, 10, 71, 72]. Furthermore, the postoperative stay in the intensive care setting was prolonged.

The initial mortality following staged, total cavopulmonary connection has decreased remarkably [73–78]. Patients who had total cavopulmonary connection without fenestration had initial mortality rates ranging from 8 to 10.5% [73–75], while subjects who had total cavopulmonary connection with fenestration had slightly lower (4.5–7.5%) initial mortality rates [76–78].

In one large single institutional study examining the results of 500 consecutive Fontan surgery patients [77], early failure was associated with high (≥19 mm Hg) mean PA pressure, young age at surgery, heterotaxy syndrome, a right-sided tricuspid valve as systemic atrioventricular valve, distorted pulmonary arteries, an atriopulmonary connection, no Fontan fenestration, and longer cardiopulmonary bypass time.

These investigators also observed that a significant improvement in morbidity and mortality from early (first quartile—early failures: 27.1%) to the more recent time (last quartile—early failures: 7.5%) occurred [77]. This progress appears to be related to increasing surgical and intensive care experience as well as to more recently introduced Fontan modifications.

### **5.2 Follow-up results**

Long-term follow-up results were also poor with older types of Fontan [9, 10]. The late mortality rates varied from 1 to 11%, and when early and late mortality rates were combined, they varied between 11 and 25%. The need for reoperations was present in 1–11% of patients. Factors adversely influencing late mortality and reoperation rates are earlier calendar year of operation, age of patient at the time of surgery, type of prior palliative procedures, hypoplasia, distortion or obstruction of PAs, subaortic obstruction, significant mitral valve insufficiency, elevated PA pressure or resistance, decreased left ventricular function, increased left ventricular muscle mass, asplenia syndrome, and others [9, 10].

Following the introduction of staged cavopulmonary anastomosis (both lateral tunnel and extra-cardiac conduit diversion of IVC blood to the PA), the long-term outcomes have improved. In one study in which results of follow-up for 10.2 ± 0.6 years of 196 patients were examined, the estimated Kaplan-Meier survival was 93 and 91% at 5 and 10 years, respectively [79]. An equally impressive finding was freedom from supraventricular arrhythmias in 96 and 91% of patients at 5 and 10 years following surgery. In a different study, the actuarial survival 15 years following surgery was 85% [80]. But, late re-interventions were necessary in 12.7% of patients. When lateral tunnel and extra-cardiac conduit types of Fontan were compared, the outcomes were found to be similar for both groups [81, 82].

Using fenestration during Fontan appears to improve early mortality and morbidity, particularly demonstrated in high-risk patents [83]. A more recent analysis in a smaller group of patients did not demonstrate significant advantage of fenestrated Fontan over the non-fenestrated [84]. However, the general consensus is that using fenestration during Fontan decreases mortality and morbidity during the postoperative period [30, 76–78].

## **6. Follow-up protocol and complications**

Periodic follow-up following Fontan is generally recommended. These patients are evaluated at 1, 6, and 12 months after Stage IIIB (device closure of fenestration) and yearly thereafter. During the follow-up, platelet-inhibiting doses of aspirin 2–5 mg/kg/day in children or clopidogrel 75 mg/day in adults to prevent thrombus formation and angiotensin-converting enzyme inhibitors for afterload reduction are generally prescribed. Electrocardiograms and echocardiograms are generally

**141**

in rare occasions.

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

some of these complications will be presented.

ventricular arrhythmias are less frequent.

**6.2 Development of obstruction in Fontan pathways**

**6.3 Residual arterial desaturation and paradoxical emboli**

**6.1 Arrhythmias**

performed during evaluation of these patients with additional imaging studies, as

During follow-up, a number of complications were reported, and these include arrhythmias, obstructed Fontan pathways, cyanosis, paradoxical emboli, thrombi, development of collateral vessels, and protein loosing enteropathy [30, 31, 85]. These complications appear to be more frequent with older types of Fontan than with the currently used staged, total cavopulmonary connection with extra-cardiac conduit and fenestration. When such complications develop, they should be promptly investigated and treated. In the ensuing paragraphs, a brief review of

indicated. Any abnormalities, as and when detected, are addressed.

Arrhythmias were more frequently seen in patients with old Fontan (atriopulmonary connection) than with staged TCPC. The observed arrhythmias

supraventricular tachycardia. Initially, anti-arrhythmic medications are used to control the rhythm disturbance. This should be followed by hemodynamic and angiographic assessment to identify obstructive lesions in the Fontan pathways. The obstructive lesions should be treated with balloon angioplasty, stent, or surgery, as applicable. Continued rhythm abnormality calls for radiofrequency ablation. Although the success rate of radiofrequency ablation is high in 80% range [86], rates of recurrence range from 30 to 40%. In subjects who have resistant arrhythmias, reducing the atrial mass, switch to TCPC with concomitant Maize procedure is advisable [87]. A few patients develop atrioventricular block or sick sinus syndrome which may require pacemaker implantation. Fortunately,

Obstructions in Fontan circulation may occur. Obstructive lesions in the SVC or IVC may arise but are less frequently seen. However, branch pulmonary artery stenoses may be seen more often. Obstructions within the lateral tunnel or extracardiac conduit are also uncommon, but may occur due to thrombus formation and will be addressed in the section on "Thrombus formation." In the presence of signs and symptoms indicative of obstruction in the Fontan pathway, prompt investigation to confirm such obstruction should be made. While echo studies are useful in young children, poor echo windows in adolescents and adults may require MRI and CT, and/or angiographic studies to confirm or exclude such obstructive lesions. If the obstructive lesions are detected, they should be promptly relieved by balloon angioplasty or stent implantation (**Figure 11**) [88]. Surgery may be needed

Sometimes connections between lateral tunnel and extra-cardiac conduit on the one hand and the atrium on the other persist. These residual defects and intentionally created Fontan fenestrations result in right-to-left shunt because the pressure in the Fontan conduit is higher than that of the atrial pressures. These residual defects will result in arterial desaturation and may become the site of paradoxical embolism with consequential transient ischemic attacks (TIAs), cerebrovascular accidents (CVAs), and systemic emboli. These residual defects as well as Fontan fenestrations should be occluded by transcatheter techniques

were typically atrial arrhythmias, namely, atrial flutter/fibrillation and

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

performed during evaluation of these patients with additional imaging studies, as indicated. Any abnormalities, as and when detected, are addressed.

During follow-up, a number of complications were reported, and these include arrhythmias, obstructed Fontan pathways, cyanosis, paradoxical emboli, thrombi, development of collateral vessels, and protein loosing enteropathy [30, 31, 85]. These complications appear to be more frequent with older types of Fontan than with the currently used staged, total cavopulmonary connection with extra-cardiac conduit and fenestration. When such complications develop, they should be promptly investigated and treated. In the ensuing paragraphs, a brief review of some of these complications will be presented.
