2. • Normal mammal cardiovascular system
double circuit connected in series
—systemic
—pulmonary
• powered by a double pump
—the right and left heart
3. • Many complex cardiac malformations - one
functional ventricle
• Maintain systemic and pulmonary circulation - not
connected in series but in parallel
• Major disadvantages
– arterial desaturation
– chronic volume overload to single ventricle - in
time impair ventricular function
4. • 1971, Fontan and Baudet
• Goal was to create a circulatory system in
which the systemic venous blood enters the
pulmonary circulation, bypasses the right
ventricle, and thus places the systemic and
pulmonary circulations in series driven by a
single ventricle
• All shunts on the venous, atrial, ventricular
and arterial level are interrupted
5. • Advantages of a Fontan circuit include
– (near) normalisation of the arterial saturation
– abolishment of the chronic volume overload
• Cost for such a circulation includes
– Chronic hypertension and congestion of the
systemic veins
– decreased cardiac output
• Cardiac output is no longer determined by the
heart,but rather by transpulmonary flow
6. INDICATIONS FOR A FONTAN CIRCUIT
• Cardiac malformation and a single functional chamber
– dysfunctional heart valve
– absent or inadequate pumping chamber
• Tricuspid atresia
• Pulmonary atresia with intact ventricular septum
• Hypoplastic left heart syndrome
• Double-inlet ventricle
7. SELECTION OF PATIENTS 1978, Choussat et al
• 10 criteria for optimal results following the Fontan
1. age at operation between 4 and 15 years
2. presence of normal sinus rhythm
3. normal systemic venous connections
4. normal right atrial size
5. normal pulmonary arterial pressure (mean≤ 15 mmHg)
6. low pulmonary vascular resistance (4 Woods units/m2)
7. adequate-sized PA with diameter ≥75% of the aorta
8. normal left ventricular ejection fraction ≥ 60%
9. absence of mitral valve insufficiency
10. absence of complicating factors from previous surgeries
8. • Refined by many centres
• After repair
– LA pressure must be low (determined by good LV fn)
– transpulmonary gradient must be low (determined by
the pulmonary vasculature)
• Cardiac requirements nowadays are
– unobstructed ventricular inflow (no atrioventricular
valve stenosis, no regurgitation)
– reasonable ventricular function
– unobstructed outflow (no subaortic stenosis, and no
coarctation
9. • Pulmonary requirements
– non-restrictive connection from systemic veins to
the PA
– good sized PA without distortion
– a well developed distal vascular bed
– (near) normal PVR - 2.5 U/m2
– unobstructed pulmonary venous return
– Marc Gewillig , Heart 2005;91:839–846. doi: 10.1136/hrt.2004.051789
10. Fontan Procedure
• Since its original description, the Fontan
circuit has known numerous modifications
• Early modifications of the Fontan procedure
connected pulmonary arteries to the right
atrium
11. • Original procedure included
– SVC to RPA anastomosis (Glenn shunt)
– Anastomosis of RA appendage to LPA directing IVC flow
through a valved homograft
– Placement of a valved homograft at the IVS-RA junction
– Closure of the atrial septal defect
12. • RA was included to - improve pulmonary
blood flow, being a pulsatile chamber
• Instead RA dilated and
lost contractile function
– Turbulence and energy loss
– Decreased pulmonary blood flow
de Leval et al
13. • Right atrial–pulmonary circuits - obsolete
• Replaced with newer techniques - direct
connection between each vena cava and PA
• Bypass the right atrium and right ventricle
• More efficient cavopulmonary blood flow to
the lungs – reduce risk for arrhythmia and
thrombosis
14. • Modern Fontan procedure involves
connecting SVC and IVC to the RPA
• Originally performed at the same time
• Resulted in a marked increase in blood flow to
the lungs - pulmonary lymphatic congestion,
and pleural effusions
• No longer performed together
15. • Currently total cavopulmonary Fontan circulation done in
two stages
– To allow body to adapt to different hemodynamic states
– Reduce overall surgical morbidity and mortality
– Allows a better patient selection and intermediate preparatory
interventions
16. • As no ventricular contraction to pump blood through
the lungs, elevated PAH is an absolute
contraindication for Fontan procedure
• At birth, it is impossible to create a Fontan circulation
– PVR is still raised for several weeks
– Caval veins and pulmonary arteries - too small
17. • Initially in the neonatal period, management must aim
to achieve
• Unrestricted flow from the heart to the aorta
– coarctectomy
– Damus- Kaye-Stansel
– Norwood repair
• Well balanced limited flow to the lungs
– pulmonary artery band
– modified Blalock-Taussig
• Unrestricted return of blood to the ventricle
– Rashkind balloon septostomy
18. Bidirectional Glenn Shunt / Hemi-fontan
• At 4–12 months of age
• First half of creating a total cavopulmonary
circulation circuit
• End-to-side anastomosis between SVC & RPA
• RPA is not divided, resulting in blood flow from the
SVC into the right and left PA
• Children may remain cyanotic because blood from
the IVC is not directed to the lungs
19. Bidirectional Glenn Shunt / Hemi-fontan
• Cardiac end of the divided SVC is attached to MPA or
the under surface of RPA
• Lower stump of SVC is connected to IVC with a conduit
• Open end of the SVC is either oversewn or occluded
with a polytetrafluoroethylene patch
• Allows Fontan circulation to be completed later
20. • When patients reach 1–5 years of age total
cavopulmonary Fontan circuit is completed
• IVC connected to pulmonary artery with a
conduit
21. • Modified Fontan directing IVC flow through
the lateral portion of the RA into PA via an
anastomosis to the underside of the RPA
• SVC flow is already directed into the RPA by a
previous bidirectional Glenn shunt
22. • Internal conduit - pass through the right atrial
chamber
• External conduit - run completely outside the
heart to the right side of the right atrium
23. Intraatrial tunnel method
• Conduit is constructed with both the lateral wall of the
right atrium and prosthetic material
• Inferior aspect of the tunnel is anastomosed to the IVC
and the superior aspect is anastomosed to the
pulmonary arteries
• Conduit enlarges as the child grows - may be used in
children as young as 1 year old
• Internal conduit may
lead to atrial arrhythmia
24. Extracardiac conduit method
• Usually performed only in older than 3 years
• PTFE tube graft is placed between the transected
IVC and the pulmonary artery, bypassing RA
• Entire atrium is left with low pressure - less atrial
distention, arrhythmia, and thrombosis
25. • Cannot enlarge as the patient grows
• Performed only in patients who are large
enough to accept a graft of adequate size to
allow adult IVC blood flow
26. Fenestrated fontan
• small opening or fenestration may be created
between the conduit and the right atrium
• Functions as a pop-off valve (a right-to-left shunt)
– prevent rapid volume overload to the lungs
– Limit caval pressure
– Increase preload to the systemic ventricle
– Increase cardiac output
• cyanosis may result from the right-to-left shunt
27. • Fenestrations decrease postop pleural effusions
• May be closed after patients adapt to new
hemodynamics
• Now, fenestrations are seldom created during the
completion of the Fontan
– improved patient selection and preparation
– improved staging
29. Early increase in preload
• Fontan circulation provides definitive palliation for
complex cardiac lesions not suitable for biventricular
repair
• Some form of palliation is done in early infancy
• Results in a parallel pulmonary and systemic
circulation and a net increase in preload
30. • Most patients undergo a staged transition to their
complete Fontan via Bidirectional Glenn
• BDG procedure leads to marked decrease in preload
• Degree of reduction depends on prior pulmonary to
systemic flow ratio, which often exceeds 2:1
• Reduction of preload results in reduced ventricular
dilation and work
Reduction of preload
31. • Abnormal systolic ventricular performance is rarely a
problem in early years of palliation prior to Fontan
– Is sustained or improved in most, after completion of
Fontan circuit
• It was shown that restoration of normal systolic wall
stress was achieved in most individuals undergoing a
Fontan procedure prior to the age of 10 years
• Sluysmans T et al. Natural history and patterns of recovery of contractile
function in single left ventricle after Fontan operation. Circulation Dec
1992;86(6):1753–61.
32. • Increase in wall thickness coincident with the acute
reduction in end-diastolic volume
• Result s in abnormalities of early relaxation &
characteristically reduced early rapid filling
• Consequently, much of diastolic filling is dependent
on atrial systole
• Early diastolic dysfunction negatively impact recovery
after subsequent Fontan operation
Early diastolic dysfunction
33. • Persistently abnormal early relaxation with worsening
ventricular compliance markedly reduces ability of the
ventricles to fill
• Reduces pulmonary blood flow
• Accounts for some of late failure seen in these
patients
• Worsen naturally with age as in the normal heart
34. • Avoidance of factors known to lead to
worsening compliance (persistent LV outflow
tract obstruction, hypertension) is of
fundamental importance
35. • While diastolic abnormalities predominate
early-on , systolic failure also becomes
apparent in some patients late after the
procedure
36. Systemic vascular bed
• Many studies have reported uniformly elevated
systemic vascular resistance after Fontan
• Senzaki H, Masutani S, Kobayashi J, et al
37. Use of ACE inhibition in Fontan patients
• Enalapril or placebo was given for 10 weeks in 18
patients approximately 14 years after the Fontan
operation
• Tendency to worsen exercise performance.
• Reduced incremental cardiac index during exercise in
the patients receiving enalapril
• Kouatli et al ,Enalapril does not enhance exercise capacity in patients after
Fontan procedure. Circulation Sep 2 1997;96(5):1507–12.
38. • Many patients continue to receive ACE inhibition, in
the hope of a beneficial effect when given chronically
• It is possible that there are subgroups that may
benefit e.g. severe systolic dysfunction
• Presently no evidence for this therapy being
beneficial
39. The veno-pulmonary circuit
• Major evolution in the hemodynamic design of the
Fontan operation since its inception
• Initial right atrial to pulmonary connection has been
abandoned in favor of more streamlined versions
40. • Cardiac output - using respiratory mass spectrometry and
an acetylene re-breathing method
• There was no difference between the patient group at
rest
• Cardiac output & respiratory rate higher in the lateral
tunnel group than the atriopulmonary group at low and
moderate workloads
• Rosenthal M et al Comparison of cardiopulmonary adaptation during exercise in children
after the atriopulmonary and total cavopulmonary connection Fontan procedures. Circulation
Jan 15 1995;91(2):372–8.
41. • Work of breathing is a significant additional energy
source to circulation in Fontan
• Normal negative pressure inspiration has been
shown to increase PBF after the atrial pulmonary
connection and TCPC
• Redington AN, Penny D, Shinebourne EA. Pulmonary blood flow after total
cavopulmonary shunt. Br Heart J Apr 1991;65(4):213–7
42. • Philadelphia group, using magnetic resonance
flow measurements,have estimated that
approximately 30% of the cardiac output can
be directly attributed to the work of breathing
in patients after the TCPC
• Fogel MA,Weinberg PM, Rychik J, et al. Caval contribution to flow in the branch pulmonary
arteries of Fontan patients Circulation Mar 9 1999;99 (9):1215–21.
43. Positive pressure ventilation
• Increasing levels of PEEP during positive pressure
ventilation is adverse to Fontan circulation
• Higher the mean airway pressure, lower cardiac index
• Maintain with minimum mean airway pressure
compatible with normal oxygenation and ventilation
• Williams DB, Hemodynamic response to positive end-expiratory pressure following right
atrium-pulmonary artery bypass (Fontan procedure). J Thorac Cardiovasc Surg Jun
1984;87(6):856–61y
44. The pulmonary vascular bed
• Low PVR is a prerequisite for early success after
Fontan operation
• Lower the total pulmonary resistance (PVR ,
pulmonary venous resistance and LA
resistance) the better
• LA resistance is influenced by the abnormal
ventricular response
45. • Structural pulmonary venous abnormalities
– Naturally occurring
– May evolve as a result of abnormal hemodynamics
• Atriopulmonary anastomosis- gross enlargement of
RA may compress adjacent pulmonary veins
46. • Abnormalities of arteriolar resistance adversely
influence early outcome, in terms of morbidity and
mortality
• Few data available regarding the long-term effects of
the Fontan circulation on the pulmonary vascular
bed.
• Pulmonary thromboembolism is not infrequent -
lead to adverse changes in vascular resistance
47. • Pulmonary artery flow in Fontan is relatively low velocity,
laminar
• Different to the normal pulsatile flow of pulmonary
vascular bed in normal circulation
• Release of nitric oxide from the endothelium is
dependent on pulsatile flow in the normal circulation
• Experimentally, reducing pulsatility leads to reduced NO
production and an increase in vascular resistance
• Nakano T et al, Pulsatile flow enhances endothelium-derived nitric oxide release in
the peripheral vasculature. Am J Physiol Heart Circ Physiol Apr 2000;278(4):
49. • Creation of Fontan circulation is palliative by nature
• Proved good results with ideal hemodynamics
• Substantial morbidity and mortality
– in those with unfavorable hemodynamics
– those who underwent older surgical techniques
50. • Risk factors for complications include
– elevated pulmonary artery pressure
– anatomic abnormalities of the right and left
pulmonary arteries
– atrial-ventricular valve regurgitation
– poor ventricular function
51. Late mortality
• Late death is directly related to the number of risk
factors for a Fontan operation
• Unfavourable haemodynamics and risk factors are
associated with an increased early and late attrition
52. Functional status and exercise tolerance
• Most patients with a Fontan circulation to lead a
nearly normal life, including mild to moderate sport
activities
• More than 90% of all hospital survivors are in NYHA
functional class I or 2
• However, with time there is a progressive decline of
functional status in some subgroups
53. Ventricular dysfunction
• Ventricle of a functionally univentricular heart
– Dilated, hypertrophic and hypocontractile
• May fail after years of systemic loading
• congenital malformation itself
• original hemodynamic state of volume overload
• Systemic ventricle may be a morphologic right or an
indeterminate primitive ventricle
• previous surgical interventions
• High RA pressure may impair coronary blood flow - affect
myocardial perfusion and function
54. • During the first months after birth - ventricle will
always be volume overloaded
• Leads to dilation and hypertrophy of LV
• After unloading at the time of a Fontan operation,
some regression to normalisation will occur -
frequently incomplete
• Currently only a small shunt is allowed to persist for
several months
55. • Ventricle thus evolves from being volume overloaded
and overstretched, to overgrown and (severely)
underloaded
• Low preload results in remodelling, reduced
compliance, poor ventricular filling, and eventually
continuously declining cardiac output
56. • Lack of reaction to classic treatment strategies has
given the ventricle in a Fontan circuit a very bad
reputation
• Little impact on ventricular function of
– inotropes, afterload reducing agents, vasodilators,
and b blockers
• no impact on the reduced preload which is the
dominant limiting factor
57. Arrhythmia
• Many old circuits have atrial wall incorporated into
the circuit causing atrial dilation
• Dilatation predispose to
– arrhythmia
– swirling of blood in the enlarged atrium - stasis &
clot formation
– results in poor blood flow to the lungs
• May have undergone atriotomy
injure the sinus node or conducting fibers
cause atrial arrhythmia
58. • Occur in up to 40% of the patients 10 years after
surgery
• Most common atrial tachycardia is intra-atrial re-
entry or atrial flutter
• Immediate direct current DC version
• Anticoagulation in view of the significant risk of a
right atrial thrombus
59. • Long term treatment of atrial arrhythmia can
involve medication and ablation
• Conversion of the old Fontan circuit to an
extracardiac cavopulmonary connection
• Together with a right atrial maze and a
reduction plasty
60. Collateral Vessels and Shunts
Collateral vessels and shunts may lead to substantial
right-to-left shunts and cyanosis
• Incomplete closure or a residual atrial septal defect
• Surgically created fenestration between the surgical
conduits and RA
• Surgical redirection of coronary sinus blood flow to LA
• Formation of pulmonary AV malformations
• Patent collateral vessels between systemic and
pulmonary veins
• Patent systemic veins that extend directly into LA
61. Left-to-right shunts
• Aortopulmonary collateral vessels
- common
• May lead to hemodynamic shunting
- results in volume overload of the systemic ventricle
- increased PBF and pulmonary pressure
• Arise from the thoracic aorta, internal mammary
arteries, or brachiocephalic arteries
62. Blood Vessels
• Increased frequency of pulmonary thromboembolic
events
– Dilated atrium
– low cardiac output
– coagulation abnormalities associated with hepatic
congestion
– chronic cyanosis–induced Polycythemia
• Massive pulmonary embolism is the most common
cause of sudden out-of hospital death in patients
with Fontan circulation
• Reported incidences of venous thromboembolism
and stroke are 3%–16% and 3%–19%, respectively
63. Pulmonary Circulation
• Fontan circulation results in a paradox of
systemic venous hypertension (mean pr >10 )
pulmonary artery hypotension ( <15 mm Hg)
• Due to absence of the hydraulic force of RV
64. • Absence of pulsatile blood flow and low mean
pressure in the PA underfill the pulmonary
vascular bed and increase PVR
• Pulmonary arteries may be morphologically
abnormal (small, discontinuous, or stenosed)
65. • PVR is an important determinant of cardiac
output in Fontan circulation
• Stenosis or leakage of surgical anastomoses
between the venae cavae and pulmonary arteries
may adversely affect pulmonary blood flow
• Patients with borderline haemodynamics have
been reported to deteriorate acutely after
moving to altitude above 2000 m
66. Lymphatic System
• Fontan circulation operates at or sometimes beyond
the functional limits of the lymphatic system
• Affected by high venous pressure and impaired
thoracic duct drainage
• Increased pulmonary lymphatic pressure may result
in interstitial pulmonary edema or lymphedema
• Leakage into the thorax or pericardium may lead to
pericardial and pleural effusions (often right-sided)
and chylothorax
67. Protein-losing enteropathy
• Relatively uncommon manifestation of failing
Fontan circulation
• Cause is unclear
• Loss of enteric protein may be due to elevated
systemic venous pressure that is transmitted to
the hepatic circulation
• Lead to hypoproteinemia, immunodeficiency,
hypocalcemia, and coagulopathy,
• May occur in the long term
68. • PLE is a relatively rare complication
• In an international multicentre study involving
35 centres and 3029 patients with Fontan
repair between 1975 and 1995, PLE occurred
in 114 patients - 3.8%
• Mertens L et al. Protein losing enteropathy after the Fontan operation J Thorac
and Cardiovasc Surg 1998;115:1063–73
• Very poor prognosis
• Five year survival rate was 59%
69. Treatment options for PLE
• Diet high in calories
• High protein content
• Medium chain triglyceride fat supplements
• Diuretics
• Several surgical options have been reported
– relief of obstruction
– conversion to streamlined cavopulmonary
connection
– atrioventricular–valve repair/replacement
70. Plastic bronchitis
• Rare but serious complication
• 1%–2% of patients
• Noninflammatory mucinous casts form in
tracheobronchial tree and obstruct the airway
• Dyspnea,cough, wheezing, and expectoration
of casts - may cause severe respiratory distress
with asphyxia, cardiac arrest, or death
• Exact cause unknown
71. Plastic bronchitis
• High intrathoracic lymphatic pressure or obstruction
of lymphatic flow may lead to the development of
lymphoalveolar fistula and bronchial casts
• Medical management is difficult - often require
repeat bronchoscopy to remove the thick casts
• Surgical ligation of the thoracic duct may cure plastic
bronchitis by decreasing intrathoracic lymphatic
pressure and flow
72. Reproduction: pregnancy
• Most females after Fontan repair have normal menstrual
patterns
• Increased systemic venous pressure may trigger
complications of right heart failure such as atrial
arrhythmias, oedema, and ascites
• Right-to-left shunt through a residual ASD will
Increase - decrease in arterial saturation
• Increased risk for venous thrombosis and pulmonary
embolus
• Successful pregnancy with delivery of normal children is
possible.
73. Coagulopathies
• Protein C, protein S, and antithrombin III deficiency
• Most common cause of sudden out-of-hospital death
in patients with a Fontan circuit
• Chronic multiple pulmonary microemboli may lead to
pulmonary vascular obstructive disease, a late
complication
– particularly lethal in a Fontan circulation.
74. • Some clinicians recommend anticoagulating every
patient with a Fontan circuit
• Subgroups of patients with a very low risk
• Full anticoagulation in
– previous thrombi
– poor cardiac output
– congestion, dilation of venous or atrial structures,
– arrhythmia
75.
76. • All patients having undergone Fontan surgery
and follow-up at Children’s Hospital Boston
were included if they were born before
January 1, 1985, and lived
77. • Type of Fontan surgery was classified into the
following 4 categories:
– Right atrium (RA)–to–PA anastomosis
– RA–to–right ventricle (RV) connection
– Intraatrial lateral tunnel (LT)
– Extracardiac conduit (ECC)
78. Baseline Characteristics
• A total of 261 patients, 121 female (46.4%)
• had their first Fontan surgery at a median age
of 7.9 years
• 33 (12.6%) of which were fenestrated
• Type of first Fontan
– RA-PA connection in 135 (51.7%),
– RA-RV in 25 (9.6%)
– LT in 98 (37.5%) ECC in 3 (1.1%)
79.
80. Mode of Death
• Over a median follow-up of 12.2 years years
• 76 patients (29.1%) died
• 5 (1.9%) had cardiac transplantation
• 5 (1.9%) had Fontan revision
• 21 (8.0%) Fontan conversion - LT in 16 or ECC in 5
• Overall, 52 deaths (68.4%) were perioperative
• 7 (9.2%) were sudden
• 6 (7.9%) were thromboembolic
• 5 (6.6%) were due to heart failure
• 2 (2.6%) were secondary to sepsis
81.
82. Perioperative Mortality
• Of 52 perioperative deaths, 41 (78.9%) were early
and 11 (21.1%) were late
• Importantly, perioperative mortality rates decreased
steadily over time
• First Fontan surgery
– Before 1982 -36.7%
– 1982 to1989 - 15.7%
– 1990 or later - 1.9%
83. Long-Term Survival
• Actuarial event-free survival rates at 1, 10, 15, 20, and
25 years were 80.1%, 74.8%, 72.2%, 68.3%, and 53.6%
• Significant disparities between Fontan categories
mainly due to periop deaths in an earlier surgical era
• In perioperative survivors, freedom from death or
cardiac transplantation was comparable among all types
84. • In early survivors, overall actuarial freedom
from death or cardiac transplantation at 1, 5,
10, 15, 20, and 25 years was 96.9%, 93.7%,
89.9%, 87.3%, 82.6%, and 69.6%, respectively
85. • Death resulting from thromboembolism
occurred at a median age of 24.9 years
• 8.7 years after Fontan surgery
• Actuarial freedom from thromboembolic
death was 98.7% at 10 years and 90.8% at 25
years
• All patients had RA-PA Fontan surgeries except
for 1 patient with an LT
86. Predictors of Thromboembolic Death in Perioperative
Survivors
• Atrial fibrillation
• Lack of aspirin or warfarin therapy
• Thrombus within Fontan
87. Heart failure
• Heart failure–related deaths occurred at a
mean age of 22.9
• 4.3 years after Fontan surgery
• Actuarial freedom from death caused by heart
failure was 99.5% at 10 yrs and 95.8% at 25 yrs
• Risk factors were single RV morphology, higher
postoperative RA pressure, and protein-losing
enteropathy.
88. Sudden death
• Sudden death occurred at a median age of
20.2 years in 7 patients
• 3 with RA-PA, 3 with LT, and 1 with RA-RV
• 2.9 years after Fontan surgery.
89. Conclusions
• Leading cause of death was perioperative,
particularly in an earlier era
• Gradual attrition was noted thereafter,
predominantly from thromboembolic, heart
failure–related, and sudden deaths
• 70% actuarial freedom from all-cause death
or cardiac transplantation at 25 years
Hinweis der Redaktion
Such a circuit has two
(itself mainly determined by pulmonary vascular resistance)
such as pulmonary artery distortion
These two connections are
A benefit of using this circuit is that the
has been reported
Prolongation of the time constant of early relaxation (tau) and the isovolumic relaxation time are both inversely related to the c
Coronary sinus blood may be surgically redirected to drain into the left atrium (3).
The treatment of ventricular dysfunction in the setting of a
Fontan circuit is very frustrating for a cardiologist.
The latter 2
were considered subtypes of total cavopulmonary connections.