What is a Fontan?

- palliative surgery which is performed in patients with a functional or an anatomic single ventricle
- ventricle which is rudimentary or <30% of the expected volume.

What are the typical anatomy for which a Fontan is performed?
- HLHS
- Tricusid atresia
- Unbalanced AV canal
- PA/IVS
- DILV

Rarely it may need to be performed in conditions such as
- Ebstein's
- DORV
- ccTGA
- any anatomy where there is severe hypoplasia of one of the ventricles

Concept behind a fontan
- there is a single ventricle and its job needs to be dedicated to pumping to the systemic circulation
- therefore there is passive flow of blood through the Fontan
- blood driven by central venous pressure
- intra thoracic pressure changes
- relaxation of the systemic ventricle

10 COMMANDMENTS FOR A SUCCESSFUL FONTAN PROCEDURE
1. Age - 2-7years of age
2. sinus rhythm
3. Normal systemic venous drainage
4. Normal right atrial volume
5. No/ minimal AVVR
6. Normal single ventricle function
7. Normal PA and branch PA anatomy
8. Normal size PA's (PA to Aortic diameter>0.75)
9. Normal PVR (<4iWu)
10. Normal PA pressure (<15mmHg)

 Specialized care of a Fontan is needed following surgery
- annual clinic visit with echo and EKG
- annual renal, albumin and CBC
-10 years post Fontan or complex Fontan with issues
  annual hepatic profile
- 5 years post fontan - perform liver imaging (MRI/CT) every 3-5years  
- no formal guideline about stress testing and holters but get them either annually

If there unexplained volume retention, fatigue, exercise limitation, arrhythmia, cyanosis or hemoptysis a cardiac catheterization must be performed 

 Post operative survival rate 15-20year is 60-85%

 Long term issues in Fontans

10 years after Fontan operatiion the risk for arrhythmia is 20% for SVT and 50% for patient with AP fontan's.
New onset atrial arrhythmias in a fontan patients needs to be evaluated well - look for electrolyte or thyroid problems or structural problem - fontan obstruction, valve dysfunction or ventricular dysfunction. Secondary complications from this should be identified such as ventricular dysfunction or intra atrial thrombus

all Fontan patients with atrial arrhythmias need to be on systemic anticoagulation.

TEE is recommended for all fontan patients with atrial arrhythmia needing cardioversion inspite of being on anticoagulation due to their high risk of having clots.

cyanosis in a fontan patient
- if fenestration - can get cyanotic
- if no fenestration - think of VV collaterals, pulmonary AVM's, unintentional fenestration

Ventricular (Systolic/ diastolic) dysfunction in a fontan patient

ACE I and lasix may be used in this situation, pacing
there is not much evidence for use of ACE I in these patients
(ref Enalapril does not enhance exercise capacity in patients after Fontan procedure.
AU
Kouatli AA, Garcia JA, Zellers TM, Weinstein EM, Mahony L
SO
Circulation. 1997 Sep;96(5):1507-12

PLE 
- 3-18% of fontan patients (incidence 3%)
- presenting time - few weeks to few years 
- mean time 3.5years after a fontan

presenting symptoms - bloating, diarrhea, abdominal pain, effusions in pleural and pericardial space
lab findings - hypoalbuminemia, hypogammaglobulinemia, lymphopenia


This is a great flow chart explaining the mechanism for PLE (taken from Up to date)

Exercise recommendations :
(Source: Up to date)
The 36th Bethesda Conference provides a guideline for the Fontan patient interested in competitive sports participation. These guidelines do not necessarily apply to non-competitive sports activities. Patients are recommended to undergo full evaluation before competitive sports participation, including a chest radiograph, ECG, echocardiography or MRI, and cardiopulmonary exercise testing. The specific sport-based recommendations for Fontan patients include:
●Athletes can participate in low-intensity competitive sports (class IA). These sports include billiards, golf, riflery, curling, bowling, and cricket.

●If the patient has normal ventricular function and normal oxygen saturations, they can also play class IB sports (baseball/softball, table tennis, fencing, volleyball).

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