Subido por Florentino Vargas

Bidirectional cavopulmonary shunt . Florentino J. Vargas et al.

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Bidirectional
With Multiple
Cavopulmonary
Risk Factors
Shunt
in Patients
Florentino J. Vargas, MD, Gustav0 Mengo, MD, Juan P. Gallo, MD, Carlos B. Skerl, MD,
Maria E. Ranzzini, MD, and Juan C. Vazquez, MD
Unit r)t Pediatric CarLiio\,Isculal.
~~~rg~~r\. tlclspital Italianlr, Ru~,nil\ ,\IRY, ;\I-g:r,ntin,l
Rnck~~ro~r~rl. Twenty-five
patients in whom a modified
Fontan operation
was deferred because of multiple
risk
factors underwent
a bidirectional
cavopulmonary
shunt.
Two or more of the following
risk factors were present in
all: age less than 1 year, severe pulmonary
artery distortion, impaired
left ventricular
function,
subaortic
obstruction,
anomalous
systemic-pulmonary
venous connection, atrioventricular
valve incompetence,
and increased
mean pulmonary
artery pressure.
Met/rods. Adhitional
procedures
included
take-down
of systemic-pulmonary
artery shunt, atria1 septectomy,
pulmonary
artery reconstruct’ion,
bulboventricular
foramen enlargement,
and atrioventricular
valve repair.
lic~lts.
There were three hospital deaths (12’4 ). Mean
follow-up
is 21 months. There was no late mortality.
Mean oxygen saturation
increased
from 71% to 83’:
Results obtained
from pulmonary
artery reconstruction,
enlargement
of bulboventricular
foramen, and atrioventricular valve repair were satisfactory
for the patients in
whom these risk factors were present preoperatively.
Ventricular
function
also improved
in the survivors
in
whom it was previously
deteriorated,
this being related
to the suppression
of the sources of ventricular
volume
overload.
(‘or~lrrsior~s.
In this risk group of patients for a modified Fontan operation,
a bidirectional
cavopulmonary
shunt provided
adequate
palliation
at reasonable
low
risk. Early bidirectional
cavopulmonary
shunt would
minimize
complications
originating
from systemicpulmonary
shunts such as pulmonary
artery distortion
and the potential
harm of chronic ventricular
volume
overload.
S
Material
ince the original
report ot the USC’ of the Fontan
principle
in tricuspid
atrc\ia,
it ha5 been w,idel\,
applied to a variety of complex form5 of congenital
heart
disease\. ‘The original crittsria tor st,lt>ction of patient5 a\
proposed
bv Choussat
and .l\sociates
hn\,e been reviewed and the indication5
t~*panded [I I. I low;ever, ct’rtain risk factors prevail
II\ a cao~
ot morbidit\
and
mortalitv.
These include 5~1 tnrc di\tortion
of thtx puImonary arteries
[2, .3], impairc,d
v<lntricular
function
141,
subnortic
obstruction
151, anomalous
s\steniic-palmooat-\’ vc‘nous connection
lh], atrio\,cntricul‘~r
(,AL )
valve incompetence
171, increasc,d mean pulmonary,
artet-v pressure (PAP) 171, and I opt ag:c 1I, 71. A poor \ut-glc‘?
result after a modified
tontan
ijperation
~wuld
hc c+pectcd if some of thcs\c ri\k tactor+ arc prt>sent simuIt;~neouhlv
in the preoprrativ~~
;Is~c~ssnient.
For tht+c>
patients, creation of a hidir~ctlc~nal
~-;1vol?Lllfiion,Ir\ and\tomosis (BCP) Ma5 ad\,ocattzd 15, Xl ‘15 an alternati\zc>
either as a part of a \taged mc)diiit,J f ontan proccdurt~ OI
as a dcfinitivt>
palliation.
lo thi\ rtlport LZ’L’ anal\/<% the,
immediate
and niidtcrm
outconic in a \erics ot patit,nt\
in whom multiplc~ riik tactor\ IIC’I-I’ ttncountered.
and Methods
Since 1991 a total of 25 patients underwent
BCP for
palliation
of the following
forms of cyanotic congenital
heart diseases: univentricular
heart (16), hypoplastic
right \ entricle (6), and mitral stenosislatresia
with small
left ventricle (3).
I&trictivc
pulmonary
blood flow was present in all
(either pulmonary
stenosis/atresia
or pulmonary
artery
banding).
‘Twenty-two
of the 25 patients (SS”/“) had undergone one or more prior systemic-pulmonary
artery
shunt\ (B-T shunt), and a previous pulmonary
artery band
\\‘a\ present in 2. Mean preoperative
oxygen saturation
\\CIS
‘ 71”,~. Significant
degrees of cyanosis or incapacity
detc~rmined
the surgical
indication.
All patients
were
~~~~~~udcd from a modified
Fontan type of procedure
bc~au~~ ot the presence of two or more of the following
i-i\h factors (Table 1):
I. :\ge. Eight (32”,,) patients
were aged less than 12
months. Ages for the series ranged from 4 months to 9
\‘t’ars (mean, 2.5 years).
7. Severe pulmonary
artery distortion.
Pulmonary
artery
anatomv
was considered
inadequate
in 7 patients
r2X”,,) (sig 1). Anatomic findings as displayed from the
preoperative
angiograms
were severe kinking
and
diffusc~ narrowing
of the main right pulmonary
artery
l-1), of both main right and left pulmonary
arteries (2),
and anatomic
discontinuity
between
right and left
0003-4975/95/$9.50
\SDI
0003-4975(95)00815-2
cardiographic
examination.
Eight additional
patients
had moderate degrees of AV valve insufficiency.
5. Subaortic
obstruction.
Seven patients
(28%) had a
restrictive
ventricular
septal defectlbulboventricular
foramen
causing subaortic
obstruction,
which was
defined
from hemodynamic
criteria
in 2 (gradient
%50 mm Hg either basal or isoprenaline
induced)
or
by morphologic
criteria in 5 (angiographic
or echocardiographic
demonstration
of a 50% or greater reduction in end-systolic
caliber of the narrowest
subaortic
segment relative to aortic size) (Fig 2A). Five had a
I)-loop and 2 an L-loop type of ventricular
arrangement. Signs of severe ventricular
hypertrophy
were
present in all.
h. Anomalous
systemic/pulmonary
venous connection.
Four patients had a bilateral superior vena cava. In 1,
an interrupted
inferior vena cava drained to the right
~upt~rior vena cava via hemiazigos
continuation.
Four
patients had the pulmonar!
vtxins draining to the right
\idtb ~)f a common atrium, and the pulmonary
venous
IC,~UIn was directed to the right superior vena cava in
111,I ~a&
mean puln~on.~r\~ artery pressure.
Mean
I’.\I’ was greater than 18 nlm Hg in 12 patients (48%).
1’11or \,t,ntricular
function (7), A\/ \,alve incompetence
I IO), rebtrictive foramen ovate (coexisting with left AV
\,al\,e stenosis or atresia) (3), and previous BT shunts
112) bvt’re identified
as concurrent
causes for the incremented mean PAP. Pulmonarv
vascular resistances
iz t’rc Itlb!, than 4 Wood unitbln?.
Bidirec-tional
cavopulmonar):
anastomosis
was pertormed through a median sternotomy
and cardiopulmonarv b! pabs in all patients. The azygos vein was ligated,
c%xcept in a patient with interrupted
inferior vena cava.
Bilateral
BCP was performed
in patients with bilateral
superior
cava. The aorta was cross-clamped
to perform
an atrial heptectomy in 9 patients, for AV valvoplasty
in 2,
and for enlargement
of the ventricular
septal defect/
bulbo\~entricul,r
foramen in 7. In the latter, the ventricular septal defect was enlarged
toward the apex in 5
(D-v~~~tricular
loop) and to the inferior part of the defect
in 2 (L-ventricular
loop) through a transaortic
approach.
Pulmonary
artery distortion
was treated by augmentation with .tutologous
pericardium
(7). Pulsatile
pulmonar\’ blood flow was obtained
from a previous contralaterai B7 shunt, which M’as left open in 10, and from the
ventricltb (antc,grade flow) in 3. In all patients with the
combinaltion
of diastolic overload, depressed ventricular
tunctitrn,
and increased
mean pulmonary
artery prespure, no zourcc’ of pulsatile
pulmonary
blood flow was
Itaft (B’I ligation). Pulmonary
artery was ligated or closed
bv o\.tsrsewing the pulmonarv
valve leaflets from inside
in -I patients.
Kesults
I hree ot the 25 patients died (12”,ll). Three or more risk
tactor\ were present in each, including
depressed ventl-ocular tunction,
increased
PAP, pulmonary
artery dis-
Ann Thorac Surg
1995;60:5558-62
tortion,
and restricted
bulboventricular
foramen
in 1,
depressed
ventricular
function,
AV valve insufficiencv,
and increased PAP in another, and restrictive bulbovcntricular
foramen,
severe pulmonary
arterv- distortion,
anomalous
systemic/pulmonarv
venous connection,
and
increased
mean PAP in the remaining
1 (see Table I).
One patient was reoperated
on within the first 23 hour\
postoperatively
to ligate a previous BT shunt, which had
been left open (pulsatile
flokv) due to increased superior
vena cava pressure and excessive pulmonarv
blood flokv.
In another patient with an L-loop ventricular
arrangement in whom enlargement
of bulbo\:cntricular
foramen
was done, complete AV block developed
and a permanent pacemaker was implanted
before discharge. Chvlothorax developed
in 1 patient but responded
to medical
therapy. Persistent pleural effusions were not present in
the remaining.
Midterm
follow-up
ranged from 8 months
to 3.8 years (mean, 2.1 months).
There has been no late mortalit!.
Mean ox)gt’n saturation of the survivors is 83”~~. The\ are routinelv
receiljing diuretics,
digoxin,
and aspirin.
Two-dimensional
color Doppler studies showed remarkable
improvement
of the ventricular
function in the survivors of the group
with poor preoperative
ventricular
function (mean postoperative
fractional
shortening,
0.31; mean velocity ot
circumferential
fractional
shortening,
1.5 c/s). Satisfactory size of the augmented
pulmonar\
arteries was displayed by echocardiographic
examination,
M.ith unrestricted flow into the repaired pulmonary
artery through
the BCP. This correlated with adeyuatc pulmonarv
blood
flow shown both from the chest roentgenograms
and
radionuclear
perfusion studies in the prcx\iouslv compromised lung. Doppler
echocardiogt-aph\,
aIs;, showed
good function of the AV valve in the \ur\,ivor in \vhom an
AV valvoplasty
was performt~d.
For the remaining
8
patients
with moderate
Al \.al\,ct incompetence,
this
markedly improved
or disappeared.
Satisfactory enlargement of the ventricular
septal dt~tt~ctibulboventricular
foramen with relief of the previous subaortic obstruction
cvas confirmed
by two-dimensional
color Doppler studies
in all patients (Fig 28). Pulsatile flow in the pulmonary
artery was confirmed
in patients with a pulsatile type of
BCP (either those in whom a previous BT shunt was left
open or those with antegrade flow from the ventricle) (Fig
.?I. Radionuclear
studies showed preferential
perfusion of
the right lung in patients with either pulsatile or nonpulsatilc flop. No difference in perfusion
between the lungs
\\‘a~ observed
in patients in whom bilateral
BCP was
performed.
Two patients underwent
completion
of Fontan circulation
successfully 2 and 2.7 years after BCP.
Comment
Expansion of the indication
for the Fontan procedure
to a
\\idr spectrum of patients with complex cardiac malformations has yielded to a more precise knowledge
of the
risk factors involved
and their significance
in terms of
survival and quality of life [l-7]. At this point, we assume
that patients with concurrent
risk factors are definitely
at
J higher risk, making
a modified
Fontan procedure
disadvisable.
Bidirectional
cavopulmonary
anastomosis
appears as a good alternative
for staging procedures
or as
a definitive
palliation.
This study concerns a group of
patients excluded from a modified Fontan operation
due
to multiple
risk factors in whom BCP was performed.
Anv statistical inference from the data in this small series
i\ hpen to criticism. Due to the presence of several of
these factors in each of the patients who died (see Table
I ), It is difficult to infer their individual
relevance
as a
cause of mortality.
Satisfactory
augmentation
with autologous
pericardium was obtained
in all patients
with preoperative
distortion
of the pulmonary
arteries. Interestingly,
inadequate pulmonary
anatomy was the result of previous
palliative
operation
in all but 1 of the patients reported.
This fact should lead us to emphasize an effort to initially
avoid
BT shunts when po>siblt~ 13, 31 01., more ft~asible, to
shorten the time elapsed between a 87 shunt performed
in the neonatal period and the BC‘P 191.
Ventricular
function improv~~i
markcdlv
in the sur\,ivors in whom it was depresst-d yrt,opt~rati\,cl\.
‘Two <It
them had been refcrrcld to our hospital for tranbplantation. The modification
ot the vtrlumc 01 tnrload after BC’I’
and BT ligation (with AL’ \al\(’ rcpnir when ncccs>ar\ i
should contribute
to impro\ CY~ \,vntricular
prrformanct~
in these patients.
Both elimination
crf the* hourcc ot
diastolic overload
and impro\ c>ment ot thts m~ocardlal
oxvgenatlon
added to the bc*nt+it obtainc>J M*ith tht,
procedure.
In thih regard, it i\ again important
to con-sider the advantages ot perfornling
HCI’ and khunt ligation earlier in life to minimilt,
the potentially
harmtul
effect of long-standing
diastolic overload on thcssc \,rntrlcles 191. This is even more t!<scntial in patient:, bvith ‘1
single morphologic
right vt~ntric‘lt~. Significant
degree>\ (It
AV valve incompetence
M,ill r<‘quirts \ur$cal
repair at tht,
time of BCP proccdurt~. t-loL\c\;c~r, h paticant5 in this st‘rics’
preoperativelv
sho\\~i
moderate
dts:f-~‘ch ot A\’ \*,iI\ t’
insufficicnci,,
‘which improv~~d atttbr f3C I’ and RI shunt
ligation.
Ai ~‘a5 pre\,iouslL,
rt>portcd,
tht’ mentit~nt~d
postoperati\,tx
elimination
ot that diastolic
ventricular
overload co~rld explain
this ~~il~~nc~tnt~nc~~l
/l)l.
Complex cardiac anomalies with buhaorti< clb~tructil>n
reprv>ent a difficult therapeutic
probicm
C.ombination
ot
a modified Darnils-Ka\,~-St,llis~,l
anastr)mosl\
\t,ith a BC‘I’
has becr~ adwcated
‘24 <I mtd~td
of tr-<~,ltrw~>t
ior thc5<*
patients in the prcsencc of unrt’stric tcti pulmonar\
bloo~i
flow 151. UnfortunateI\,
in this scrit,s. thta prc~5t~ii~‘~’ of
pulmonary
stenosis or atr(+ia ~*~ludt~d thli .Iltt>rnati\ c,
the r~nlargemtint
of tht, vt,ntri<ular
\c%ptal def’ctti
bulbovcntricular
foramc~n beiris th<a singlca option. Patients with I,-loop ventricular
;Irrangt~nl~*nt a~‘<~at hight:r
ri\h ot injur\. to the conduction
system. One patient in
our series required
permanent
pacemaker
implantation
als a result of surgically
induced
complete
AV block.
Adcyuatc
relief of subaortic obstruction
was obtained
in
this seric5 as demonstrated
by the postoperative
twodimensional
color Doppler
studies. The presence
of
anomalous
5vstemic/pulmonarv
venous return encountc*rcd in oL,r &ics did not q&sent
an additional
probIcLm in management.
However, other forms of anomalous
pulnionar\~ venous return imply a more complex surgical
tcchniquc~ to be performed
at the time of BCP. In the
~IWWIIW
ot elevated mean PAP as a result of previous
shunts,
.A\’ valve insufficiency,
or depressed left ventricular function, a good functioning
BCP was obtained (with
s.lti5factor\
superior
vena cava pressures)
after BCP
p~~rformancc
and either BT shunt ligation
or AV valve
plastv (\2 ith consequent
impro\;ement
in the ventricular
tunition).
s\nalogous benefit on the PAP was obtained by
c,nlarging .I restrictive foramen ovale in cases with mitral
\,al\ c’ \tcnosis/atresia
and small left ventricle. NevertheIi’+, undr’sirablcx results arc to be expected if preoperati\c pulmonarv
vascular resistances are greater than 4
111)cd
unit5iml’.
Low ,rgts did not show itself as a factor affecting
mc~rtalitv. On the other hand, the advantages of performing RC I’ as carlv as possible have been discussed above
IL)]. Iwclvc patients in our series were left with a pulsatile
source of pulmonary
blood flow. When deciding,
it is
diEi<-uft to predict preoperative/y
if functioning
of the
id\.olIllllmonarv
circulation
will be compatible
with a
pul\atilt~ source of pulmonary
blood flow. One of our
patient\ rt’quirtxd ligation of a BT shunt during the first 24
hlrurs postc)ptrati\;el~.
We have no evidence to support
that this ht)modvnamic
condition
is preferable
to a nonpuI5atilc~ situation.
Wc can speculate
that pulsatility
5562
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Ann l-horac
2 t
be of benefit
by avoiding
the potential
development
of pulmonarv
arteriovtanous
fistula;
it also could
help
provide
normal
growth
of the contralateral
pulmonary
artery
after
BCP. These
theoretic
advantages
need
further
clinical
confirmation.
Finally,
although
BCP appears
a rc>awnable
alternative
in this group
of patients,
some
doubts
arise
regarding
their
management
in the long
term
[lOI. Some
of them
will
never
become
ideal
Fontan
candidates,
some
will
require
coil embolization
of vkmous
collaterals,
and perhaps
some
will be considered
for transplantation.
On the
other
hand,
some
patients
\vill bt, suitable
for modified
Fontan
operation,
and in this c“aw it becomes
difficult
to
define
the proper
timing
for the scwmd
stage.
In our
opinion,
there
is no clear adl,antagt)
in offering
a different
kind
of palliation
to a patitant
Lvho i\ doing
reasonably
well.
could
References
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