Bidirectional inferior vena cava-pulmonary artery shunt.

Abstract

Bidirectional superior vena cava-pulmonary shunt is widely used as an interim palliation for patients with univentricular hearts. Bidirectional inferior vena cava-pulmonary artery shunt, as an alternative approach of partial Fontan circulation, may offer the advantage of performing the complete Fontan circulation more easily due to the already constructed inferior vena cava lateral tunnel.
We used bidirectional inferior vena cava-pulmonary artery shunt in 2 patients. Contraindications to a complete Fontan circulation were due to, respectively, a volume-overloaded systemic ventricle and an irregular pulmonary arterial tree.
Postoperative courses were uneventful. There were no significant pleural effusions. Transcutaneous oxygen saturations were 77% and 78%. Pulmonary-to-systemic blood flow ratios were 0.57 and 0.63. A complete Fontan circulation was safely performed 8 and 12 months later, without any "Fontan-related" complications.
Bidirectional inferior vena cava-pulmonary artery shunt can be useful in selected patients with univentricular hearts, although its place in the field of "partial Fontan operations" cannot be determined as yet.

Full text

Page 1

Bidirectional Inferior Vena Cava-Pulmonary
Artery Shunt
Loic Mac6, MD, Patrice Dervanian, MD, Jean Losay, MD, Thierry A. Folliguet, MD,
Jean-Michel Grinda, MD, Sami Abdelmoulah, MD, Jean-F61ix Verrier, MD,
Francesco Santoro, MD, and Jean-Yves Neveux, MD
Department of Cardiovascular and Pediatric Cardiac Surgery, Marie Lannelongue Hospital, Paris-Sud University, Paris, France
Background. Bidirectional superior vena cava-pulmo-
nary shunt is widely used as an interim palliation for
patients with univentricular hearts. Bidirectional inferior
vena cava-pulmonary artery shunt, as an alternative
approach of partial Fontan circulation, may offer the
advantage of performing the complete Fontan circulation
more easily due to the already constructed inferior vena
cava lateral tunnel.
Methods. We used bidirectional inferior vena cava-
pulmonary artery shunt in 2 patients. Contraindications
to a complete Fontan circulation were due to, respec-
tively, a volume-overloaded systemic ventricle and an
irregular pulmonary arterial tree.
Results. Postoperative courses were uneventful. There
were no significant pleural effusions. Transcutaneous
oxygen saturations were 77% and 78%. Pulmonary-to-
systemic blood flow ratios were 0.57 and 0.63. A complete
Fontan circulation was safely performed 8 and 12 months
later, without any "Fontan-related" complications.
Conclusions. Bidirectional inferior vena cava-pulmo-
nary artery shunt can be useful in selected patients with
univentricular hearts, although its place in the field of
"partial Fontan operations" cannot be determined as yet.
(Ann Thorac Surg 1997;63:1321-5)
© 1997 by The Society of Thoracic Surgeons
T
hearts. Irrespective of their own indications and timing
for operation, which are still a subject of debate, several
procedures correspond to that concept: (1) the bidirec-
tional superior vena cava-pulmonary artery shunt (SCP)
[1], (2) the hemi-Fontan procedure [2], (3) the fenestrated
Fontan operation [3], and (4) the adjustable Fontan oper-
ation [4]. The common interest of such procedures is due
to the persistence of a right-to-left shunt, which de-
creases the pulmonary artery pressure, preserves the
cardiac output, and unloads the univentricular heart. As
a consequence, partial Fontan operations could be per-
formed at a younger age or safely associated with addi-
tional procedures. Conversely, each of these partial Fon-
tan circulations bears its own specificities. Among them,
the pulmonary-to-systemic blood flow ratio (Qp/Qs),
which reflects the percentage of the venous return flow-
ing through the lungs and the eventual presence of an
accessory source of pulmonary blood flow, influences the
arterial oxygen saturation [5] and pulmonary artery
growth [6]. The ease of performing a complete Fontan
circulation has also been taken into account. Partial
Fontan operations must be performed with the aim of
minimizing the consequences of the second operative
step due either to the adverse effects of the cardiopulmo-
he concept of "partial Fontan operations" is widely
recognized as an interim palliation of univentricular
Accepted for publication Nov 26, 1996.
Address reprint requests to Dr Mace, D6partement de Chirurgie Cardio-
vasculaire et Cardiaque P6diatrique, H6pital Marie Lannelongue, 133, ave
de la R6sistance, 92350 Le Plessis Robinson, France.
nary bypass and aortic cross-clamping or to a redo
dissection near the sinus node area [7].
Bidirectional inferior vena cava-pulmonary artery
shunt (ICP) may fulfill these latest criteria. This shunt
was previously used in a unidirectional form as part of a
complete or adjustable Fontan operation [8-10]. An ex-
perimental study showed that, when used in a bidirec-
tional fashion, this shunt resulted in improvement in the
venous return and cardiac output response curves [11].
The aim of this report is to evaluate the ICP shunt as an
interim palliation toward a complete Fontan operation.
Material and Methods
Of 57 patients who underwent creation of a partial
Fontan circulation from October 1989 to May 1996 in our
institution, in 2 children an ICP shunt was performed.
Patient 1
A 6-month-old male infant, weighing 6,600 g, was re-
ferred to our institution with the diagnosis of double-
outlet hypoplastic right ventricle and pulmonary steno-
sis. He underwent a modified right Blalock-Taussig
shunt. Data from catheterization at the age of 3 years 6
months and a weight of 17 kg precluded a biventricular
repair. Mean left atrial pressure was 5 mm Hg. Mean
This article has been selected for the open discussion
forum on the STS Web site:
http://www.sts.org/annals
© 1997 by The Society of Thoracic Surgeons
Published by Elsevier Science lnc
0003-4975/97/$17.00
PII S0003-4975(97)00105-7

Page 2

1322
MACE ET AL
INFERIOR VENA CAVA SHUNT
Ann Thorac Surg
1997;63:1321-5
J
\ \
Fig 1. Bidirectional inferior vena cava-puhnonary artery shunt in
patient 1.
pulmonary arterial pressure was 17 mm Hg. The pulmo-
nary artery index was 542 mmR/m 2 [12]. Arterial oxygen
saturation was 84%. Indication of a partial Fontan circu-
lation was based on the volume-overloaded systemic
ventricle as a risk factor for a complete Fontan circula-
tion.
The ICP shunt was performed on March 31, 1993. The
operative approach was a midline sternotomy. Mean
intraoperative pulmonary arterial and left atrial pres-
sures were 15 mm Hg and 10 mm Hg, respectively.
Cardiopulmonary bypass was established between the
ascending aorta and both venae cavae. Myocardial pro-
tection was obtained using cold crystalloid cardioplegia.
The main pulmonary artery and its branches were fully
mobilized. The azygos vein was divided and the superior
vena cava transected above the level of the sinus node. Its
cardiac end was enlarged toward the roof of the right
atrium. The main pulmonary artery was divided, its
cardiac end closed with a running suture. Its distal part
was enlarged toward the inferior aspect of the right
pulmonary, and an end-to-end anastomosis with the
prepared right atrium was performed. A lateral intra-
atrial tunnel [13] was constructed, using a polytetrafluo-
roethylene patch (W. L. Gore & Associates, Inc, Elkton,
MD), directing the inferior vena caval blood flow toward
the pulmonary bifurcation. The systemic part of the
superior vena cava was anastomosed end-to-side to the
roof of the left atrium due to a left juxtaposition of the
atrial appendages (Fig 1). After bypass, mean pulmonary
arterial and inferior vena caval pressures were 15
mm Hg. Mean superior vena caval and left atrial pres-
sures were 8 mm Hg. The postoperative course was
uneventful without inotropic support. The duration of
artificial ventilation was 13 hours. The duration of pleural
effusions was 3 days (29 ml/kg). Transcutaneous oxygen
saturation was between 72% and 77% at discharge.
In April 1994, a new catheterization revealed an excel-
lent angiographic aspect of the inferior vena caval lateral
tunnel (Fig 2), a mean pulmonary capillary wedge pres-
sure of 2.5 mm Hg, a mean pulmonary arterial pressure
of 8.5 mm Hg, and an arterial oxygen saturation of 74%.
The pulmonary arterial resistances were 1.8 indexed
Wood units and the Qp[Qs was 0.63. The pulmonary
artery index was 419 mm2[m 2. The right heart bypass was
completed under a circulatory bypass time of 23 minutes,
by anastomosing end-to-side the superior vena cava to
the right pulmonary artery. Mean pulmonary arterial and
left atrial pressures were 16 mm Hg and 5 mm Hg,
respectively. No postoperative inotropic support was
necessary. The patient was ventilated for 10 hours. The
duration of pleural effusions was 3 days (28 mL]kg).
Transcutaneous oxygen saturation was greater than 95%.
He is doing well 2 years after this operation.
Patient 2
A 5-month-old female infant was referred for an increas-
ing cyanosis. She was diagnosed, using color-coded
echocardiography and angiography, as having a double-
inlet right ventricle with pulmonary atresia and noncon-
fluent pulmonary arteries arising from the aorta at the
isthmic level. She first underwent a left modified Blalock-
Taussig shunt, and subsequently, 9 months later, a right
modified Blalock-Taussig shunt. When she was 38
months old, weighing 13 kg, a new angiography and
cardiac catheterization were performed to assess the
possibility of performing a Fontan circulation. The mean
right pulmonary arterial pressure was 12 mm Hg, and
pressure could not be measured in the left pulmonary
artery. The Nakata index was 397 mm2/m 2. Pulmonary
vascular resistances could not be calculated. The right
Fig 2, Postoperative angiogram of patient 1 showing the bidirec-
tional inferior vena cava-pulmonary artery shunt.

Page 3

Ann Thorac Surg
1997;63:1321-5
MACI~ ET AL
1323
INFERIOR VENA CAVA SHUNT
Fig 3. Bidirectional inferior vena cava-puhnonary artery shunt in
patient 2.
ventricular end-diastolic pressure was 6 mm Hg. The
indication of an ICP shunt was due to the irregularity of
the pulmonary arterial tree.
Intraoperative measurements revealed a mean left
atrial pressure of 7 mm Hg and a right pulmonary artery
pressure of 11 mm Hg. The pulmonary arterial tree was
widely dissected, and the systemic-to-pulmonary artery
shunts were divided at the beginning of the bypass. The
right superior vena cava was divided and the azygos vein
ligated. The right pulmonary artery was divided at the
level of the shunt (the retro-aortic part of the right
pulmonary artery was harvested as a pulmonary artery
autograft). The cardiac end of the superior vena cava was
anastomosed end-to-end to the right pulmonary artery.
The left pulmonary artery was divided at the level of the
shunt and anastomosed end-to-end to the pulmonary
artery autograft. Then, the reconstructed left pulmonary
artery was anastomosed end-to-side to the roof of the
right atrium. Through a longitudinal right atriotomy, a
lateral tunnel was constructed using a polytetrafluoro-
ethylene patch. The systemic part of the superior vena
cava was anastomosed to the right atrial appendage (Fig
3). After bypass, the mean pulmonary arterial and left
atrial pressures were 15 mm Hg and 7 mm Hg, respec-
tively. Artificial ventilation and inotropic support with
dobutamine were necessary for 5 days. The duration of
pleural effusions was 7 days. The volume of pleural
drainage was 67 mL/kg. Transcutaneous oxygen satura-
tion was 78% with room air at discharge.
Nine months later, a cardiac catheterization revealed a
pulmonary capillary wedge pressure of 2 mm Hg and a
mean puhnonary arterial pressure of 4 mm Hg (Fig 4).
Arterial oxygen saturation was 75% with a Qp/Qs of 0.57.
Pulmonary vascular resistances were 2.7 indexed Wood
units. The Nakata index was 271 mm2/m 2. The complete
right heart bypass was realized under normothermic
cardiopulmonary bypass (36 minutes) without aortic
cross-clamping. Before bypass, the transpulmonary gra-
dient was 5 mm Hg. The superior vena cava was anasto-
mosed end-to-side with the right pulmonary artery. After
completion of the operation, the pulmonary arterial and
left atrial pressures were 12 mm Hg and 5 mm Hg,
respectively. Transcutaneous oxygen saturation was
100%. The postoperative course was uneventful. The
duration of artificial ventilation was 20 hours. The dura-
tion of pleural effusions was 2 days (11 mL/kg). Today, 2
years after the last procedure, she enjoys a normal life
and activity without cardiac insufficiency.
Comment
We performed in 2 patients, with temporary contraindi-
cations to a complete Fontan circulation, an ICP shunt to
reduce the risks inherent to the completion of a Fontan
circulation. The clinical status of the patients was satis-
factory without symptoms of cardiac insufficiency. How-
ever, their activity was restricted due to the persistent
arterial oxygen desaturation. A complete Fontan opera-
tion could then be performed easily, without any "Fon-
tan-related" mortality or morbidity.
Hemodynamic assessments revealed that inferior vena
caval pressure was less in an ICP shunt than in a
complete Fontan circulation, as experimentally predicted
[11[. The absence of a postoperative low cardiac output
avoided both the risk of hepatic failure [14] and an
activation of the renin angiotensin system, which could
be responsible for an increase in pleural effusions [15].
Moreover, the fluid dynamics of an ICP shunt seem to be
more favorable than those of a complete derivation due
Fig 4. Postoperative angiogram of patient 2 showing the bidirec-
tional ir(ferior vena cava-pulmonary artery shunt.

Page 4

1324 MACE ET AL
INFERIOR VENA CAVA SHUNT
Ann Thorac Surg
1997;63:1321-5
to the absence of competitive flows with the superior
vena cava [13], thereby decreasing the risks associated
with the postural drainage of the inferior vena cava [16].
The Nakata index decreased after ICP shunts, as re-
ported after SCP shunts [6], probably resulting from a
decrease in the Qp/Qs. However, the ICP shunt provides
a higher transpulmonary blood flow than the SCP shunt,
and could therefore promote an additional growth of the
pulmonary arteries. However, in our opinion, the con-
struction of an ICP shunt in the very young or along with
another source of pulmonary blood flow seems contrain-
dicated and thereby cannot be offered as a definitive
palliation measure. The Qp/Qs was close to 0.6, as could
be predicted [5]. The resulting level of arterial oxygen
saturation, almost identical to an SCP shunt without an
accessory source of pulmonary blood flow, was some-
what deceiving. Even though an ICP shunt provides an
increase in pulmonary blood flow compared with an SCP
shunt, its oxygen delivery remains at a low level. This can
be partly explained due to the high venous oxygen
saturation of the renal venous blood flow that did not
participate in effective pulmonary blood flow (ie, the
venous saturation of the inferior vena cava is higher than
in the superior vena cava). Exercise of the lower limbs
does not modify the flow of the superior vena cava but
increases the flow of the inferior vena cava [17], which
can be an advantage of the ICP shunt, despite our
inability to verify these data.
Regarding the technical aspects of the construction of
the inferior vena cava-pulmonary artery connection, use
of a lateral atrial tunnel does not preclude the onset of
atrial arrhythmias [18]. Therefore, an extracardiac pros-
thetic conduit could be used to establish the inferior vena
cava-pulmonary artery connection. Nevertheless, it
could not be performed in the younger children, as for a
classic intraatrial tunnel, due to the absence of any
growth potential. Anyhow, the most impressive benefit of
the ICP shunt is the technical and hemodynamic ease of
the second operative step. This could have important
consequences on the pulmonary and myocardial func-
tions in the immediate postoperative course and on the
occurrence of sinus node dysfunction [7]. In our 2 pa-
tients, there were no surgically created conduction or
arrhythmias disorders.
Theoretically, the ICP shunt allows the hepatic venous
blood flow to go directly through the lungs with the
so-called hepatic factor, thereby avoiding the develop-
ment of arteriovenous fistulas in the lungs [19]. More-
over, there is no risk of collateralization between the
inferior vena cava and the hepatic veins. However, this
shunt does not prevent of the risk of collateralization
between the systemic venous system of the inferior and
the superior part of the body. Thus, the azygos and
hemiazygos veins must be divided and a preoperative
search for anomalies of the systemic or hepatic venous
return must be performed.
Although the inferior vena caval pressure was slightly
increased in ICP shunts, pleural effusions were minimal
due to a low pressure in the superior vena cava and
absence of any obstruction to the thoracic duct drainage
[20]. Nevertheless, it is important to observe that the
pleural effusions were more important, for the second
patient, after the ICP shunt than after the completed
Fontan circulation, probably because part of the parietal
pleural drainage is through the azygos vein [20[. In-
creased intestinal lymph production and ascites, related
to an increase in the inferior vena caval pressure and
mild obstruction to thoracic duct drainage by high supe-
rior vena caval pressure, has been cited as a possible
contributor to the development of protein-losing enter-
opathy in a few patients after the completed Fontan
procedure [20]. Theoretically, the thoracic duct could
drain at a low pressure in an ICP situation, which may
avoid this late complication.
Today, the place of the ICP shunt among the other
types of partial Fontan circulations remains to be deter-
mined. It can be offered to patients in need of a first-step
procedure before a Fontan operation because its advan-
tages are (1) a fixed Qp/Qs not dependent on the transa-
trial gradient as for the fenestrated Fontan operation [16,
21], (2) an acceptable level of arterial oxygen saturation,
and (3) mainly an increased facility to perform the second
step of the Fontan operation. Further clinical experience
will be required to determine if it should be applied as a
partial Fontan operation.
References
1. Hopkins RA, Armstrong BE, Serwer GA, Peterson RJ, Old-
ham NH Jr. Physiological rationale for a bidirectional cavo-
pulmonary shunt. A versatile complement to the Fontan
principle. J Thorac Cardiovasc Surg 1985;90:391-8.
2. Douville EC, Sade RM, Fyfe DA. Hemi-Fontan operation in
surgery for single ventricle: a preliminary report. Ann Tho-
rac Surg 1991;51:893-900.
3. Bridges ND, Mayer JE Jr, Lock JE, et al. Effect of baffle
fenestration on outcome of the modified Fontan operation.
Circulation 1992;86:1762-9.
4. Laks H, Pearl JM, Haas GS, et al. Partial Fontan: advantages
of an adjustable interatrial communication. Ann Thorac
Surg 1991;52:1084-95.
5. Salim MA, DiSessa TG, Arheart KL, Alpert BS. Contribution
of superior vena caval flow to total cardiac output in chil-
dren. A Doppler echocardiographic study. Circulation 1995;
92:1860-5.
6. Penny DJ, Pawade A, Wilkinson JL, Karl TR. Pulmonary
artery size after bidirectional cavopulmonary connection.
J Card Surg 1995;10:21-6.
7. Manning PB, Mayer JE Jr, Wernovsky G, Fishberger SB,
Walsh EP. Staged operation to Fontan increases the inci-
dence of sinoatrial node dysfunction. J Thorac Cardiovasc
Surg 1996;111:833-40.
8. Fontan F, Baudet E. Surgical repair of tricuspid atresia.
Thorax 1971;26:240-8.
9. Lins RFA, Lins MFA, Cavalcanti C, Miranda RP, Mota JH.
Orthoterminal correction of congenital heart disease: double
cava-pulmonary anastomosis. J Thorac Cardiovasc Surg
1982; 84:633-5.
10. DeLeon SY, Freeman JE, Ow EP, et al. Obligatory Glenn
shunt in fenestrated Fontan. Ann Thorac Surg 1993;56:510-4.
11. Mac6 L, Dervanian P, Weiss M, Daniel JP, Losay J, Neveux
JY. Hemodynamics of different degrees of right heart bypass:
experimental assessment. Ann Thorac Surg 1995;60:1230-7.
12. Nakata S, Imai Y, Takanashi Y, et al. A new method for the
quantitative standardization of cross-sectional areas of the
pulmonary, arteries in congenital heart disease with de-

Page 5

Ann Thorac Surg
1997;63:1321-5
MACI~ ET AL 1325
INFERIOR VENA CAVA SHUNT
creased pulmonary, blood flow. J Thorac Cardiovasc Surg
1984;88:610--9.
13. De Leval MR, Dubini G, Migliavacca F, et al. Use of compu-
tational fluid dynamics in the design of surgical procedures:
application to the study of competitive flows in cavopulmo-
nary connections. J Thorac Cardiovasc Surg 1996;111:502-13.
14. Matsuda H, Covino E, Hirose H, et al. Acute liver dysfunc-
tion after modified Fontan operation for complex cardiac
lesions. Analysis of the contributing factors and its relation
to the early prognosis. J Thorac Cardiovasc Surg 1988;96:
219-26.
15. Mainwaring RD, Lamberti JJ, Carter TL Jr, Moore JW,
Nelson JC. Renin, angiotensin II, and the development of
effusions following bidirectional Glenn and Fontan proce-
dures. J Card Surg 1995;10:111-8.
16. Laks H. Bidirectional inferior vena cava-pulmonary arte~
shunt. Reply. J Thorac Cardiovasc Surg 1994;107:1367-8.
17. Durand J, David P, Mensch-Dechene J. Measurement of the
superior vena cava blood flow of man by constant infusion of
SSKr in solution. Respiration 1969;26:47-57.
18. Gandhi SK, Bromberg BI, Rodefeld MD, et al. Lateral tunnel
suture line variation reduces atrial flutter after the modified
Fontan operation. Ann Thorac Surg 1996;61:1299-309.
19. Srivastava D, Preminger T, Lock JE, et al. Hepatic venous
blood and the development of pulmonary arteriovenous
malformations in congenital heart disease. Circulation 1995;
92:1217-22.
20. Zellers TM, Driscoll DJ, Humes RA, Feldt RH, Puga FJ,
Danielson GK. Glenn shunt: effect on pleural drainage after
modified Fontan operation. J Thorac Cardiovasc Surg 1989;
98:725-9.
21. Luisi VS, Murzi B, Bernabei M, Vanini V, Biagini A. Bidirec-
tional inferior vena cava-pulmonary artery_ shunt [Letter].
J Thorac Cardiovasc Surg 1994;107:1367.
Notice From the Southern Thoracic Surgical Association
The Forty-fourth Annual Meeting of the Southern Tho-
racic Surgical Association will be held at the Naples
Registry Resort, Naples, Florida, November 6-8, 1997.
The Postgraduate Course will be held the morning of
Thursday, November 6, 1997, and will provide in-depth
coverage of thoracic surgical topics selected primarily as
a means to enhance and broaden the knowledge of
practicing thoracic and cardiac surgeons.
Members wishing to participate in the Scientific Pro-
gram should submit an original abstract and one copy by
May 9, 1997, to Irving Kron, MD, Program Chairman,
Southern Thoracic Surgical Association, 401 North Mich-
igan Avenue, Chicago, IL 60611-4267. Abstracts must be
submitted on the Southern Thoracic Surgical Association
abstract form. These forms may be obtained from the
Association's office or in the April issue of The Annals of
Thoracic Surgery. Manuscripts of accepted papers must be
submitted to The Annals of Thoracic Surgery prior to the
1997 meeting or to the Secretary-Treasurer at the open-
ing of the Scientific Session.
Applications for membership should be completed
by September 1, 1997, and forwarded to Michael S.
Sweeney, MD, Membership Committee Chairman,
Southern Thoracic Surgical Association, 401 North Mich-
igan Avenue, Chicago, IL 60611-4267.
D. Glenn Pennington, MD
Secretary-Treasurer
Southern Thoracic Surgical Association
401 North Michigan Avenue
Chicago, IL 60611-4267
© 1997 by The Society of Thoracic Surgeons
Published by Elsevier Science lnc
Ann Thorac Surg 1997;63:1325 • 0003-4975/97/$17.00
PII S0003-4975(97)00403-7