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Objectives: Thirty-two consecutive isolated modified Blalock Taussig (BT) shunts performed in infancy since 2004 were reviewed and analysed to identify the risk factors for shunt intervention and mortality. Methods: Sternotomy was the only approach used. Median age and weight were 10.5 (range 1-74) days and 2.9 (1.9-4.4) kg, respectively. Shunt palliation was performed for biventricular hearts (Tetralogy of Fallot/double outlet right ventricle/transposition of great arteries_ventricular septal defect_pulmonary stenosis/pulmonary atresia_ventricular septal defect/others) in 21, and univentricular hearts in 11, patients. Hypoplastic left heart syndrome patients were excluded. Two procedures required cardiopulmonary bypass. Median shunt size was 3.5 (3-4) mm and median shunt size/kg body weight was 1.2 (0.9-1.7) mm/kg. Reduction in shunt size was necessary in 5 of 32 (16%) patients. Results: Three of 32 (9%) patients died after 3 (1-15) days due to cardiorespiratory decompensation. Lower body weight (P = 0.04) and bigger shunt size/kg of body weight (P = 0.004) were significant risk factors for mortality. Acute shunt thrombosis was observed in 3 of 32 (9%), none leading to death. Need for cardiac decongestive therapy was associated with univentricular hearts (P < 0.001), bigger shunt size (P = 0.054) and longer hospital stay (P = 0.005). Twenty-eight patients have undergone a successful shunt takedown at a median age of 5.5 (0.5-11.9) months, without late mortality. Conclusions: Palliation with a modified BT shunt continues to be indicated despite increased thrust on primary corrective surgery. Though seemingly simple, it is associated with significant morbidity and mortality. Effective over-shunting and acute shunt thrombosis are the lingering problems of shunt therapy.
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Modied Blalock Taussig shunt: a not-so-simple palliative procedure
Verena Dirksa, René Prêtreb, Walter Knirschc,d, Emanuela R. Valsangiacomo Buechelc,d, Burkhardt Seiferte,
Martin Schweigera,d, Michael Hüblera,d and Hitendu Davea,d,*
a
Division of Congenital Cardiovascular Surgery, University Childrens Hospital Zurich, Zurich, Switzerland
b
Department of Cardiovascular Surgery, University Hospital Lausanne, Lausanne, Switzerland
c
Department of Paediatric Cardiology, University Childrens Hospital Zurich, Zurich, Switzerland
d
Childrens Research Centre, University of Zurich, Zurich, Switzerland
e
Division of Biostatistics, Institute for Social and Preventive Medicine, University of Zurich, Zurich, Switzerland
* Corresponding author. Division of Congenital Cardiovascular Surgery, University Childrens Hospital Zurich, Zurich, Switzerland. Fax: +41-44-2668021;
e-mail: hitendu.dave@kispi.uzh.ch; hitendu@hotmail.com (H. Dave).
Received 7 January 2013; received in revised form 26 February 2013; accepted 27 February 2013
Abstract
OBJECTIVES: Thirty-two consecutive isolated modied Blalock Taussig (BT) shunts performed in infancy since 2004 were reviewed and
analysed to identify the risk factors for shunt intervention and mortality.
METHODS: Sternotomy was the only approach used. Median age and weight were 10.5 (range 174) days and 2.9 (1.94.4) kg, respect-
ively. Shunt palliation was performed for biventricular hearts (Tetralogy of Fallot/double outlet right ventricle/transposition of great
arteries_ventricular septal defect_pulmonary stenosis/pulmonary atresia_ventricular septal defect/others) in 21, and univentricular hearts
in 11, patients. Hypoplastic left heart syndrome patients were excluded. Two procedures required cardiopulmonary bypass. Median
shunt size was 3.5 (34) mm and median shunt size/kg body weight was 1.2 (0.91.7) mm/kg. Reduction in shunt size was necessary in
5 of 32 (16%) patients.
RESULTS: Three of 32 (9%) patients died after 3 (115) days due to cardiorespiratory decompensation. Lower body weight (P= 0.04)
and bigger shunt size/kg of body weight (P= 0.004) were signicant risk factors for mortality. Acute shunt thrombosis was observed in
3 of 32 (9%), none leading to death. Need for cardiac decongestive therapy was associated with univentricular hearts (P< 0.001), bigger
shunt size (P= 0.054) and longer hospital stay (P= 0.005). Twenty-eight patients have undergone a successful shunt takedown at a
median age of 5.5 (0.511.9) months, without late mortality.
CONCLUSIONS: Palliation with a modied BT shunt continues to be indicated despite increased thrust on primary corrective surgery.
Though seemingly simple, it is associated with signicant morbidity and mortality. Effective over-shunting and acute shunt thrombosis
are the lingering problems of shunt therapy.
Keywords: Modied Blalock Taussig shunt Palliation Mortality Cyanotic heart disease
INTRODUCTION
While the classic Blalock Taussig shunt was a breakthrough in
treating cyanotic heart diseases [1], it involves sacricing ante-
grade ow to the subclavian artery with its attendant risks [2,3].
In 1975, de Leval modied the technique, using a polytetra-
uoroethylene interposition graft popularly known as the modi-
ed Blalock Taussig (BT) shunt (MBTS) [4]. While MBTS has
become an established palliative procedure with progressive
improvements in the outcome [5], growing experience has led to
increasing thrust on primary corrective procedures. Palliative
strategy has obvious disadvantages, such as the need for two
operations, potentially two scars, possibility of distortion of the
branch pulmonary artery, volume loading of the ventricles, lower
diastolic pressures, etc. In spite of these, primary shunt palliation
continues to be indicated in neonates with physiological pul-
monary hypertension, which makes a bidirectional Glenn shunt
untenable. Many centres also consider a primary neonatal cor-
rection of Tetralogy of Fallot to be riddled with risks and hence,
still prefer to palliate neonates in blue spells.
While acknowledging its role even in the modern era, mortal-
ity of the MBTS procedure is relatively high, tending to be
around 10% [6]. This report is based on 32 consecutive rst
timeMBTS palliations performed at our institution since 2004,
with a view to analysing the risk factors for mortality, shunt
thrombosis and need for decongestive therapy.
PATIENTS AND METHODS
Patients
Thirty-two MBTS procedures performed in neonates and infants
at our institution since 2004 were analysed. MBTS performed in
© The Author 2013. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
European Journal of Cardio-Thoracic Surgery 44 (2013) 10961102 ORIGINAL ARTICLE
doi:10.1093/ejcts/ezt172 Advance Access publication 28 March 2013
patients with HLHS or as a part of other complex procedures,
such as unifocalization, were excluded. Twenty-six patients were
neonates and 6 were infants. Twenty-ve patients were male.
The demographic data are detailed in Table 1. Diagnosis was
established using trans-thoracic echocardiography.
End points
Primary end points were mortality and shunt thrombosis.
Secondary end points such as need for excessive inotropic
support and cardiac decongestive therapy were also analysed. A
brief analysis comparing Era 1 (200407) and 2 (200811) was
performed to see if the results had changed over time and to
identify the factors that may have accounted for that change.
Surgical technique
All MBTS procedures were performed through a sternotomy.
Two procedures required cardiopulmonary bypass. After full
sternotomy, the right lobe of the thymus was excised; the course
of the brachiocephalic trunk up to its bifurcation was dissected.
The right pulmonary artery up to the hilum was dissected.
A bolus of 100 IU/kg crystalline heparin was administered. The
brachiocephalic trunk was clamped with a Cooley clamp, and
the distal right subclavian artery, temporarily with a ligaclip.
A longitudinal arteriotomy was performed at the premarked
undersurface of the truncus to subclavian artery continuity. An
obliquely fashioned end of the thin-wall Gore-Tex stretch vascu-
lar graft (W. L. Gore & Associates, Inc., AZ, USA) was sutured
end-to-side to the arteriotomy. Clamps were released and good
shunt ow through the anastomosis ascertained. The Cooley
clamp was placed again to exclude the proximal anastomosis
from the circulation. The shunt length was trimmed so as to
avoid it being too long. The shunt lumen was ushed to remove
microthrombi. The right pulmonary artery was excluded from
circulation using two vascular clamps. The transversely fashioned
distal end of the graft was anastomosed to the right pulmonary
artery. The target arterial saturation was 7585% (Q
P
:Q
s
1).
Patent duct: to ligate or not?
Our preference was to ligate the persistent ductus arteriosus
(PDA) in all patients having forward ow through their main pul-
monary artery. In shunt-dependent circulations, the patent duct
was often circumvented and almost obliterated using a silastic
sling and ligaclips. The aim of this manoeuvre was to allow a
quick rescue by re-establishing ductal ow in case of a shunt
thrombosis emergency.
Selection of shunt size
As a rule of thumb, a 3-mm graft was used for children around
3 kg or lower in body weight, whereas a 3.5-mm graft was used
for children around 3.5 kg. The indication, whether palliating for
a univentricular or a biventricular heart, inuenced the size se-
lection in borderline weight-class children. Fine regulation of
ow and pressure was inuenced by displacing the proximal
inow anastomosis either to the proximal subclavian artery or to
the brachiocephalic trunk, as well as by slightly titrating the
length of the shunt. The details of shunt size and positioning are
summarized in Table 2.
Postoperative left open sternum
The primary goal was to close the chest at the shunt procedure.
However, if there were any fears about the fate of the shunt
(especially in totally shunt-dependent pulmonary circulation) or
about the shunt getting squeezed behind the aorta, etc. the
sternum was left open. It was believed that an open sternum
lends itself to a quick response in case of an emergency when
compared with a closed chest.
Anticoagulation
Anticoagulation regimen was decided on a case-by-case basis.
Therapeutic heparinization was performed in high-risk shunt
scenarios, such as shunt-dependent pulmonary perfusion, in
Table 1: Preoperative clinical characteristics
Variable Median (range)
N32
Age (days) 10.5 (174)
Weight at operation (kg) 2.9 (1.94.4)
Size (cm) 48 (3952)
Body surface area (m²) 0.2 (0.140.24)
SpO
2
(%) 85 (5095)
Diagnosis n(%)
TOF/DORV/TGA_VSD_PS, pulmonary
atresia_VSD, Ebsteins anomaly
21 (66)
Single ventricle inclusive of pulmonary
atresia_intact septum
11 (34)
TOF: Tetralogy of Fallot; DORV: double outlet right ventricle; TGA:
transposition of great arteries; VSD: ventricular septal defect; PS:
pulmonary stenosis.
Table 2: Shunt procedure details
Variable N(%) except otherwise
stated
No. of shunts (mm)
3 8 (25)
3.5 19 (59)
4 5 (16)
Inflow
Subclavian artery 12 (38)
Truncus brachiocephalicus 20 (63)
Outflow
Right pulmonary artery 28 (88)
Left pulmonary artery 4 (13)
Heart lung machine 2 (6)
Absolute shunt size (mm) 3.5 (34)
Median shunt size/body weight ratio
(mm/kg)
1.21 (0.91.7)
CONGENITAL
V. Dirks et al. / European Journal of Cardio-Thoracic Surgery 1097
cases with shunt clipping (shunt size reduction) or technical pro-
blems encountered during shunt construction. Heparin infusion
starting with 510 IU/kg/h, followed by therapeutic dose as early
as 2 h postoperatively, was planned if surgical bleeding was not
an issue. In effect, however, the therapeutic anticoagulation was
often achieved later than 2 h. Shunts without complications and
considered normal risk received aspirin in the long term.
Three patients did not have long-term anticoagulation/platelet
inhibitor medication: 2 who died early and 1 who survived with
early shunt thrombosis in a neonatal Ebsteins anomaly with
antegrade pulmonary ow.
All patients were evaluated postoperatively with trans-thoracic
echocardiography.
Statistical analysis
Statistical analysis was performed using IBM SPSS Statistics 19
(SPSS, Inc., Chicago, IL, USA). Categorical variables are presented
as numbers with percents and are compared using Fishers exact
test. Continuous variables are presented as median with range
and are compared between groups using the MannWhitney
test. P-values <0.05 were considered signicant.
RESULTS
Mortality
Three of the 32 (9%) patients died at a median of 3(115) days.
The details of patients who died are as presented in Table 3.
Lower body weight (P= 0.04) and bigger shunt size/kg of body
weight (P= 0.004) were signicant risk factors for mortality
(Table 4).
Shunt thrombosis
Acute shunt thrombosis was observed in 3 of the 32 (9%)
patients, none of whom died. These 3 patients had Ebsteins
anomaly with antegrade pulmonary ow (2.2 kg 3 mm right
MBTS), double outlet right ventricle-hypoplastic left ventricle
(LV)_pulmonary stenosis (2.9 kg 3 mm right MBTS) and unba-
lanced atrio-ventricular septal defect hypoplastic LV
d-transposition of great arteries_pulmonary stenosis (3 kg 3.5
mm left MBTS). All shunt thrombosis occurred within the rst
24 h and were diagnosed by echocardiography. Two patients
had shunt revision with evacuation of the thrombus. One patient
with stable saturation due to normal antegrade pulmonary ow
was not subjected to shunt revision. Shunt thrombosis could not
be statistically related to shunt size (P= 0.1) or shunt size/kg
body weight (P= 0.92). Early anticoagulation regimen (P= 0.33),
competitive blood ow (P= 1.0), diagnosis (P= 0.27), need for
cardiopulmonary bypass (P= 0.18), increased inotropic support
(P= 0.71) and shunt size reduction (P= 1.0) were not associated
with acute shunt thrombosis.
Inotropic support
Need for adrenalin 0.05 and/or noradrenaline 0.05 and/or
milrinone 0.75 μg/kg/min was dened as normal inotropic
support. Accordingly, 6 of the 32 (19%) patients needed normal
inotropic support and 23 of the 32 (72%) needed higher ino-
tropic support. Three patients were without any ionotropic
support.
Decongestive therapy
Need for cardiac decongestive therapy (over and above that of
diuretics) was necessary in 10 of 29 survivors to discharge.
Decongestive therapy was required in 2 of 19 (20%) biventricular
hearts compared with 8 of 10 (80%) univentricular hearts
(P< 0.001), obviously resulting in a signicantly longer hospital
stay (P= 0.005). Bigger shunts were associated with the need for
decongestive therapy (P= 0.054).
Open thorax
The sternum was left open postoperatively in 11 (34%) patients.
Other complications
Postoperative complications included chylothorax, phrenic nerve
palsy, necrotizing enterocolitis and abdominal bleeding with
unclear focus in 1 patient each.
Corrective surgery
Of the 29 survivors, 28 (97%) have undergone corrective surgery
with takedown of the BT shunt at the time of this study. Ten
patients were subjected to a bidirectional Glenn anastomosis,
while 18 underwent a biventricular repair. None of the shunt
survivors died during or after the corrective surgery.
Fate of branch pulmonary artery
Seven of 28 patients (25%) had reconstruction of the branch pul-
monary artery at the distal shunt insertion site. Residual stenosis
after BT shunt takedown occurred in 6 patients. In 3 of the
patients, the stenosis occurred despite the pulmonary artery
being reconstructed, while in 3, the stenosis occurred without
the artery being reconstructed.
Era
A brief comparative analysis between 12 shunts in Era I and 20
shunts in Era II is depicted in Table 5.
DISCUSSION
An ideal shunt helps promote uniform growth of the pulmonary
arteries, without causing distortion. An excessive shunt results in
signicant diastolic run-off in the short term and elevated pul-
monary vascular resistance or impaired ventricular and atrioven-
tricular valve performance in the long term. Although various
types of shunts have been described [1,711], it is the MBTS that
V. Dirks et al. / European Journal of Cardio-Thoracic Surgery1098
has become established as the procedure of choice [4,12]. MBTS
continues to be a subject of academic interest, because of per-
sistent risks associated with this simple-looking procedure.
Sternotomy or thoracotomy
MBTS was classically performed through a thoracotomy.
However, recent trends have shown increasing preference for a
sternotomy approach [6]. A sternotomy saves the child from a
second scar, avoids morbid damage to the thorax with pro-
spects of late scoliosis, but more importantly, the target pul-
monary artery being intrapericardial, it is more accessible for
eventual reconstruction after takedown. Avoiding a thoracotomy
in the prospective Fontan patients has an added advantage of
reducing build-up of lung adhesions to the thoracic wall and
the consequent development of systemic-to-pulmonary artery
collaterals. Other disadvantages of a thoracotomy approach
enumerated in the literature include Horners syndrome, distor-
tion of lobar branch pulmonary arteries and preferential ow to
one lung with unbalanced growth [6]. Depending on the side of
the thoracotomy, it may not be always possible to perform
PDA ligation, but with a sternotomy, it is always possible. In the
end, whether or not to close the duct remains a strategic
decision [13].
The sternotomy approach does confront the surgeon with the
challenges of a central run-off from the systemic artery leading
to greater steal, low diastolic pressures, coronary malperfusion
and pulmonary hyperperfusion. In addition, the often-used
truncus brachiocephalicus to the right pulmonary artery shunt
may be at danger of being squashed between the dominant
aorta and the superior vena cava, for which the parietal pericar-
dial reection over the superior vena cava to the trachea should
be divided to create space for the shunt.
Table 3: Mortality details
Diagnosis Age
(days)
Weight
(kg)
Shunt size
(mm)
Cause of death Died
(Postop day)
DORV_TGA_PS 19 2.5 3.5 Cardiorespiratory
decompensation
15
Pulmonary atresia VSD, hepatopulmonary syndrome, catheter
perforation and emergency shunt
4 2.2 3.5 Cardiorespiratory
decompensation
1
Pulmonary atresia intact ventricular septum 6 2.4 4 Myocardial ischaemia 3 (ECMO)
DORV: double outlet right ventricle; TGA: transposition of great arteries; PS:pulmonary stenosis; ECMO: extra corporeal membrane oxygenation.
Table 4: Risk factors for mortality
Variable Alive
n(%)
Dead
n(%)
P-value
N29 3
Weight (kg) 2.94 (1.94.4) 2.37 (2.22.49) 0.04
Diagnosis
Biventricular hearts 19/29 (66) 2/3 (67) 1.00
Univentricular hearts 10/29 (34) 1/3 (33)
Competitive pulmonary flow 21/29 (72) 1/3 (33) 0.22
Use of heart lung machine 2/29 (7) 0/3 (0) 1.00
Size of shunt (mm):
3 8/29 (28) 0/3 (0) 0.47
3.5 17/29 (59) 2/3 (67)
4 4/29 (14) 1/3 (33)
Shunt size/kg body weight 1.19 (0.881.58) 1.59 (1.411.69) 0.004
Anticoagulation regimen:
1 LDH 7/28
a
(25) 0/2
c
(0) 0.38
2 ETH 4/28
a
(14) 1/2
c
(50)
3 LTH 17/28
a
(61) 1/2
c
(50)
Long-term anticoagulation 7/28
a
(25) 0/1
b
(0) 1.00
Postoperative high ionotropes 20/29 (69) 3/3 (100) 0.52
Shunt size reduction 3/29 (10) 2/3 (67) 0.056
Shunt thrombosis 3/29 (10) 0/3 (0) 1.00
SaO
2
postoperative (day of operation) 83 (7794) 85 (8090) 0.97
Hospital stay 23 (595) 3 (115) 0.02
LDH: low dose (10 IU/kg/h) heparin; ETH: early therapeutic heparin; LTH: late therapeutic heparin.
a
One patient data missing.
b
One patient on immediate ECMO was not analysed for acute anticoagulation regimen.
c
Two patients who died early were not analysed for long-term anticoagulation.
CONGENITAL
V. Dirks et al. / European Journal of Cardio-Thoracic Surgery 1099
While the proposed alternative shunts such as Potts or
Waterston/Cooley shunts were difcult to regulate, the MBTS
ow is restricted by the size of the graft as also by the size of the
inow vessel.
While the Boston group [6] reported four times higher risk of
shunt failures through a thoracotomy when compared with a
sternotomy, Shauq et al.[13] have reported signicantly longer
ventilation time, inotropic support, intensive care unit (ICU) stay
and hospital stay in the sternotomy group. These ndings reect
the learning curve involved with shunts created through a
sternotomy.
Competitive ow and PDA strategy
A completely left open duct may be difcult to regulate in the
presence of a MBTS. With our technique of duct obliteration
using a silastic sling, one retains the possibility of quickly restor-
ing duct patency in the case of a shunt thrombosis. While a
patent duct imparts signicant safety in the case of a shunt
failure, some reports have associated patent duct with shunt
thrombosis [14]. Petrucci et al. (Society of Thoracic Surgeons
[STS] database) have shown no association between closed duct
and the risk of composite morbidity [15]. Closing or keeping the
duct open during the MBTS procedure has advantages and dis-
advantages and, hence remains in the end, an individual
decision.
Mortality
In spite of overall improvement in results [5], mortality reported
ranges from 2.3 to 16% [15]. Our overall postoperative mortality
was 9.4%. Low body weight (P= 0.041) and bigger shunt size/kg
body weight (P= 0.011) were factors associated with post-
operative mortality. There was a trend towards signicance
between the need for postoperative shunt size reduction and
mortality (P= 0.056). These ndings point towards over-shunting
as a possible indicator of mortality in our series. The Boston
group has reported a mortality of 9 of 102 (8.7%) patients, with
indications that excessive pulmonary blood ow could have con-
tributed to mortality in the sternotomy group. Multivariate risk
factors for mortality in their analysis included small graft size, left
MBTS and male sex [6]. The same group also suggested the use
Table 5: Comparison between eras
Variable Era I (200407)
n(%)
Era II (200811)
n(%)
P-value
N12 (38) 20 (62)
Diagnosis
Biventricular hearts 6/12 (50) 15/20 (75) 0.25
Univentricular hearts 6/12 (50) 5/20 (25)
Weight (kg) 2.89 (2.24.4) 2.93 (1.93.8) 0.99
Size of shunt (mm) 3.5 (3.54) 3.5 (33.5) 0.002
Shunt size/weight 1.24 (0.911.69) 1.16 (0.881.58) 0.13
Presence of competitive blood flow 7/12 (58) 15/20 (75) 0.44
Use of HLM 0/12 (0) 3/20 (10) 0.52
Shunt distribution, mm (in %)
3 0/12 (0) 8/20 (40) 0.001
3.5 7/12 (58) 12/20 (60)
4 5/12 (42) 0/20 (0)
Right vs left 11/20 (92) right 17/20 (85) right 1.00
1/12 (8) left 3/20 (15) left
Site of take-off (truncus brachiocephalicus vs subclavian artery) 10/12 (83) vs 2/12 (17) 10/20 (50) vs 10/20 (50) 0.08
Early anticoagulation strategy
Low dose 3/10 (30) 4/20 (20) 0.71
Early therapeutic 1/10 (10) 4/20 (20)
Late therapeutic (as defined in Table 4) 6/10 (60) 12/20 (60)
Long-term anticoagulation
Aspirin 8/10 (80) 14/19 (74) 1.00
Therapeutic 2/10 (20) 5/19 (26)
Postoperative ionotropic support
None 1/12 (8) 2/20 (10) 0.48
Normal 1/12 (8) 5/20 (25)
High
a
10/12 (83) 13/20 (65)
Need for shunt reduction 3/12 (25) 2/20 (10) 0.34
Decongestive therapy (more than diuretics) 6/9 (67) 4/20 (20) 0.03
Duration of ventilation 2 (115) 1.5 (09) 0.53
ICU stay 4 (115) 5 (113) 0.39
Duration of hospital stay 18.5 (195) 22.5 (584) 0.69
Mortality 3/12 (25) 0/20 (0) 0.04
Shunt thrombosis 0/12 (0) 3/20 (15) 0.27
SaO
2
before takedown 82 (7293) 81.5 (7394) 0.66
Residual branch PA stenosis at shunt insertion site 4/9 (44) 1/15 (7) 0.05
a
Normal ionotropic support is defined as adrenalin 0.05 and/or noradrenaline 0.05 and/or milrinone 0.75 μg/kg/min.
V. Dirks et al. / European Journal of Cardio-Thoracic Surgery1100
of smaller (3.5 mm) shunts through a sternotomy approach
instead of the 4-mm shunts for the thoracotomy approach. An
STS database harvest study [15] has identied preoperative venti-
lation, pulmonary atresia_intact ventricular septum, univentricu-
lar hearts and weight <3 kg as risk factors for mortality.
Pulmonary atresia with intact ventricular septum, when specic-
ally analysed, did not come out as a signicant risk factor for
mortality in our cohort, probably because of small numbers.
While Alkhulaiet al.[16] identied weight <2 kg and preopera-
tive ventilation, Rao et al.[17] identied restrictive atrial septal
defect, univentricular physiology and postoperative intervention
as risk factors for mortality.
Shunt thrombosis
Shunt thrombosis is a grave complication of the MBTS proced-
ure. Our overall acute shunt thrombosis of (3 of 32) 9.4% corre-
sponds with those of (9 of 76) 11.8% reported from Bristol and
(14 of 102) 13.7% reported from Boston [6]. We could not show
an association between smaller shunt size and occurrence of
thrombosis, probably because of the small numbers. Tsai et al.
[18] and Tamisier et al.[12] have suggested that young age and
smaller size are signicantly related to shunt thrombosis. Other
reports have also linked weight <2 kg [16] and weight <3.6 kg [19]
to shunt thrombosis. Gedicke et al.[14] have found weight <3 kg,
high preoperative haemoglobin (>18 g/dl) and a postoperative
patent duct as signicant factors for shunt thrombosis.
Anticoagulation-coagulopathy
Although an association between an anticoagulation regimen
and shunt thrombosis could not be established in our study, it
does not belittle the role of postoperative anticoagulation, par-
ticularly in high-risk patients. Al Jubair et al.[20] have shown,
less-shunt failure occurs if heparin is given before clamping. An
early postoperative phase with a fresh anastomosis, coupled with
phases of low systemic pressures, pulmonary hypertension, ex-
ternal compression and resulting stasis, can initiate thrombus
formation. It is these uncertainties that can be positively inu-
enced by early anticoagulation. Li et al.[21] have demonstrated a
benecial effect of acetylsalicylic acid in infants palliated with a
shunt, with reduced incidence of shunt thrombosis and death.
Another prospective study has shown the benecial effect of
haemodilution with a signicantly higher shunt patency rate [22].
Rare coagulopathies, such as protein C deciency [23], and
primary antiphospholipid syndrome [24] have also been
reported to cause shunt thrombosis.
Late shunt obstruction
We have not observed any late shunt thrombosis in this series of
patients. This has been reported as a cause in up to 15% of
out-of-hospital mortalities [14,15]. Wells et al.[25] have observed
>50% obstruction of the MBTS in 21% of their patients and have
identied a shunt size of <4 mm to be a risk factor for high-
grade stenosis (>50%).
Era
While the cohort did not change over time in terms of most
demographic and procedural variables, shunt size was signi-
cantly lower in the latter half of the series when compared with
the former half. Shunt thrombosis was higher in the later era,
but did not reach statistical signicance. These ndings may indi-
cate that small shunts are prone to shunt thrombosis. Mortality
as well as need for cardiac decongestive therapy was signicantly
higher in the previous era. With time, while mortality was
avoided, shunt thrombosis remained worrisome. While shunt
thrombosis morbidity could be partially attributed to the tech-
nique, the importance of optimal intensive postoperative man-
agement cannot be overemphasized. Interestingly, in spite of
smaller shunt size selection in the later era, transcutaneous satur-
ation before shunt takedown was 82% in both the eras. This
implies that the shunt ow was adequately regulated by the
artery from which the shunt was sourced.
LIMITATIONS
This is a retrospective study with a small patient cohort, which
may not be powered enough to identify all risk factors contribut-
ing to the various end points. The series being spread over a
time frame of 8 years, even generalized improvements in opera-
tive technique and perioperative care may alone account for the
improvements in outcome.
CONCLUSION
In spite of increasing condence with primary neonatal intracardiac
repairs, the MBTS continues to be indicated for malformations
of the univentricular pathway. Although seemingly innocuous,
the MBTS procedure is associated with signicant morbidity and
mortality. While small shunts may have a tendency to shunt throm-
bosis, large shunts may lead to pulmonary over-circulation and
volume loading of the heart. Various studies have identied
low body weight, small shunt size, over-shunting, univentricular
heartsspecically pulmonary atresia with intact ventricular
septum, to be risk factors associated with postoperative morbidity
and mortality. It appears that timely and efcient early anticoagula-
tion as well as long-term antiplatelet therapy may help reduce the
risk of early and late shunt dysfunction.
Conict of interest: none declared.
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... Almost 20% of children with complex types of congenital heart disease (CHD) have duct-dependent pulmonary perfusion after birth [1], with a need for intravenous prostaglandin E1 (PGE1) to ensure the patency of ductus arteriosus [2][3][4][5]. Within days after birth, neonatal cardiac surgery needs to be performed [1] with a systemic-to-pulmonary shunt insertion, e.g., a modified Blalock-Taussig (mBTS) shunt, to secure pulmonary perfusion for a longer period of time until the subsequent surgical procedure [6][7][8]. However, such palliation is still associated with relevant perioperative morbidity and increased interstage mortality [9,10]. ...
... Third, neonatal PDA-stenting seems a feasible and safe treatment option in the case of ductdependent pulmonary perfusion. However, both these discussed treatment strategies-the surgical shunt procedure as well as continuing PGE1 infusions-have limitations with regard to perioperative and interstage morbidity, 10% mortality as a shunt procedure complication [3,7,8,10,24,25] and the need for vascular access and long-term hospitalisation, attributed to PGE1 infusions [5,23]. ...
... This may be explained by the PDA stent being in a more "natural" position or angle [12,19] compared to the flow pattern of an aortic-to-pulmonary shunt, as recently shown by Emarsafawy and coworkers [19]. On the other hand, the RPA is limited in growth development as the blood flow through the stented PDA favours the LPA [3,6,7,24,25]. Our data confirm these findings. ...
Article
Full-text available
Background: Stenting of patent ductus arteriosus (PDA) is a minimally invasive catheter-based temporary palliative procedure that is an alternative to a surgical shunt in neonates with duct-dependent pulmonary perfusion. Methods: An observational, single-centre, cross-sectional study of patients with duct-dependent pulmonary perfusion undergoing PDA-stenting as a stage I procedure and an analysis of short- to mid-term follow-up until a subsequent surgical procedure (stage II), with a focus on the interstage course. Results: Twenty-six patients were treated with PDA-stenting at a median (IQR) age of 7 (4-10) days; 10/26 patients (38.5%) (6/10 single pulmonary perfusion) were intended for later univentricular palliation, 16/26 patients (61.5%) (13/16 single pulmonary perfusion) for biventricular repair. PDA diameter was 2.7 (1.8-3.2) mm, stent diameter 3.5 (3.5-4.0) mm. Immediate procedural success was 88.5%. The procedure was aborted, switching to immediate surgery after stent embolisation, malposition or pulmonary coarctation in three patients (each n = 1). During mid-term follow-up, one patient needed an additional surgical shunt due to severe cyanosis, while five patients underwent successful catheter re-intervention 27 (17-30) days after PDA-stenting due to pulmonary hypo- (n = 4) or hyperperfusion (n = 1). Interstage mortality was 8.6% (2/23), both in-hospital and non-procedure-related. LPA grew significantly (p = 0.06) between PDA-stenting and last follow-up prior to subsequent surgical procedure (p = 0.06). RPA Z-scores remained similar (p = 0.22). The subsequent surgical procedure was performed at a median age of 106 (76.5-125) days. Conclusions: PDA-stenting is a feasible, safe treatment option, with the need for interdisciplinary decision-making beforehand and surgical backup afterwards. It allows adequate body and pulmonary vessel growth for subsequent surgical procedures. Factors determining the individual patient's course should be identified in larger prospective studies.
... However, the coexisting PDA may be a dangerous flow source for the pulmonary circulation, resulting in pulmonary overperfusion and diastolic runoff of systemic circulation (El-Rassi et al., 2012). These two sources increase the difficulty in regulating the pulmonary blood flow during the perioperative period (Dirks et al., 2013). ...
... Excessive pulmonary blood flow may lead to pulmonary overperfusion and diastolic runoff of the systemic circulation. Insufficient pulmonary perfusion would cause inadequate oxygen delivery, thrombosis, shunt occlusion, and an underdeveloped pulmonary artery (Fenton et al., 2003;Dirks et al., 2013). The ideal value of Q P /Q S is slightly <1, which helps provide adequate pulmonary blood flow and oxygen delivery without reducing systemic perfusion and myocardial blood flow (Barnea et al., 1994(Barnea et al., , 1998. ...
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Full-text available
The question of preserving the patent ductus arteriosus (PDA) during the modified Blalock–Taussig shunt (MBTS) procedure remains controversial. The goal of this study was to investigate the effects of the PDA on the flow features of the MBTS to help with preoperative surgery design and postoperative prediction. In this study, a patient with pulmonary atresia and PDA was included. A patient-specific three-dimensional model was reconstructed, and virtual surgeries of shunt insertion and ductus ligation were performed using computer-aided design. Computational fluid dynamics was utilized to analyze the hemodynamic parameters of varied models based on the patient-specific anatomy and physiological data. The preservation of the PDA competitively reduced the shunt flow but increased total pulmonary perfusion. The shunt flow and ductal flow collided, causing significant and complicated turbulence in the pulmonary artery where low wall shear stress, high oscillatory shear index, and high relative residence time were distributed. The highest energy loss was found when the PDA was preserved. The preservation of PDA is not recommended during MBTS procedures because it negatively influences hemodynamics. This may lead to pulmonary overperfusion, inadequate systemic perfusion, and a heavier cardiac burden, thus increasing the risk of heart failure. Also, it seems to bring no benefit in terms of reducing the risk for thrombosis.
... Pulmonary over circulation can result in pulmonary edema with reduced pulmonary compliance, decreased gas exchange and oxygen saturation, pleural effusion, systemic hypoperfusion, and consequently hemodynamic instability, especially in singleventricle patients. So far, surgical revisions have been reported to treat medically-refractory pulmonary over circulation resulting from large SPS (74)(75)(76)(77). Surgical approach for SPS downsizing remains the gold standard, yet it is a risky procedure in most patients. ...
Article
Full-text available
Background Patients with cyanotic complex congenital heart defects (CHDs) commonly undergo palliation with interposition of systemic-to-pulmonary shunts (SPSs). These palliative shunts are rarely found in adults with CHDs and can be complicated with progressive obstruction or total occlusion during follow-up. The best treatment option for shunt re-permeabilization is challenging and case-oriented because most patients are high risk candidates for redo surgeries. We aimed to review the current evidence on percutaneous stent implantation to treat failed SPSs. Methods We performed a comprehensive literature review on percutaneous stent implantation to treat failed and occluded SPSs. We also reported the case of a 33-year-old man with cyanotic CHD and a occluded central aorto-pulmonary shunt, who was successfully treated with percutaneous balloon dilatation and subsequently stent implantation at our institution. Result We identified and included 31 articles reporting on 150 patients and 165 stent implantations in failed SPSs. The age of patients at the time of stent implantation ranged from 6 days to 47 years. The time between the surgical shunt creation and transcatheter intervention ranged from 1 day to 17 years. Overall, 161/165 (97.5%) stent implantations were successful. The most common clinical presentation was cyanosis and decreased atrial oxygen saturations and the indication for stent implantation was shunt obstruction and stenosis. Conclusion This review highlights the benefits of endovascular stenting to permeabilize failed SPSs in children and adults with complex CHD who are classified as poor candidates for re-surgical repair.
... On the contrary, if the shunt is oversized, a state of pulmonary overflow with consequent diastolic pressure and systemic perfusion decrease is detected. From the clinical state of the art, it appears clear that MBTS sizing is pivotal in managing complex congenital heart diseases [10,11]. ...
Article
Full-text available
The Modified Blalock Taussig Shunt (MBTS) is one of the most common palliative operations in case of cyanotic heart diseases. Thus far, the decision on the position, size, and geometry of the implant relies on clinicians’ experience. In this paper, a Medical Digital Twin pipeline based on reduced order modeling is presented for fast and interactive evaluation of the hemodynamic parameters of MBTS. An infant case affected by complete pulmonary atresia was selected for this study. A three-dimensional digital model of the infant’s MBTS morphology was generated. A wide spectrum of MBTS geometries was explored by introducing twelve Radial Basis Function mesh modifiers. The combination of these modifiers allowed for analysis of various MBTS shapes. The final results proved the potential of the proposed approach for the investigation of significant hemodynamic features such as velocity, pressure, and wall shear stress as a function of the shunt’s morphology in real-time. In particular, it was demonstrated that the modifications of the MBTS morphology had a profound effect on the hemodynamic indices. The adoption of reduced models turned out to be a promising path to follow for MBTS numerical evaluation, with the potential to support patient-specific preoperative planning.
... However, there remains a significant risk of morbidity and mortality with this surgical procedure. [3][4][5][6][7] Over the last decade, PDA stent has emerged as a viable alternative to APS. 8,9 Ductal stent is a less invasive approach compared with APS and avoids the need for cardiopulmonary bypass in the vulnerable neonatal period which allows for faster recovery. 8,10,11 Nevertheless, PDA stent also carries risks of procedural complications and increased need for reinterventions. ...
Article
Background In patients with ductal‐dependent pulmonary blood flow, initial palliation includes catheter‐based patent ductus arteriosus (PDA) stent or surgical aortopulmonary shunt (APS). This meta‐analysis aimed to compare outcomes between PDA stent and APS. Methods and Results A comprehensive literature search yielded six retrospective observational studies. Pooled adjusted hazard ratios (HR) were included to control for covariates and assess time to event analysis. Of 757 patients, 243 (32.1%) underwent PDA stent and 514 (67.9%) underwent APS. Pulmonary atresia with intact ventricular septum and expected biventricular repair were more common with PDA stent compared with APS (39.6% versus 21.2%, P <0.001 and 57.9% versus 46.6%, P =0.007, respectively). There was no statistically significant difference in mortality between PDA stent and APS (HR, 0.71; [95% CI, 0.26–1.93]; P =0.50). PDA stent was associated with lower risk of postprocedural complications (odds ratio [OR], 0.45; [95% CI, 0.25–0.81]; P =0.008), mechanical circulatory support (OR, 0.27; [95% CI, 0.09–0.79]; P =0.02), and shorter intensive care unit length of stay (−4.03 days; [95% CI, −5.99 to −2.07]; P <0.001), hospital length of stay (−5.54 days; [95% CI, −9.20 to −1.88]; P =0.003), and duration of mechanical ventilation (−3.41 days; [95% CI, −5.29 to −1.52]; P <0.001). There was no difference in pulmonary artery growth or hazard of unplanned reintereventions. Conclusions PDA stent has a similar hazard of mortality compared with APS. Benefits to PDA stent include shorter duration of mechanical ventilation, shorter hospital length of stay, and fewer complications. Differences in patient characteristics exist with more patients with pulmonary atresia with intact ventricular septum and expected biventricular repair undergoing PDA stent.
... 5,6 Various risk factors have been identified as resulting in worse outcomes for patients receiving mBT shunts, including the age and weight of the child at the time of surgery, the size of the shunt, pulmonary atresia with intact ventricular septum (PAIVS) and preoperative shock or acidosis. 5,[7][8][9] The immediate postoperative period following insertion of the mBT shunt is when the patient is most vulnerable. According to Petrucci et al., 33% of deaths in neonates undergoing mBT shunt procedures occurred within 24 hours of surgery, with 75% occurring within the first month. ...
Article
Full-text available
Objectives: A modified Blalock-Taussig (mBT) shunt procedure is a common palliative surgery used to treat infants and children with cyanotic congenital heart disease (CCHD). This study aimed to report the outcomes of infants and children undergoing mBT shunt procedures in Oman. In addition, risk factors associated with early mortality, inter-stage mortality and reintervention were assessed. Methods: This retrospective cohort study was conducted from January 2016 to December 2018 at the National Heart Centre, Muscat, Oman. All paediatric patients with CCHD undergoing mBT shunt procedures as a primary palliative procedure during this period were included. Data were retrieved from electronic hospital records. Kaplan-Meier survival curves were used to describe overall survival. Results: A total of 50 infants and children were included in this study. The in-hospital mortality and interstage mortality rates were 10% and 6.7%, respectively. Preoperative mechanical ventilation (odds ratio [OR] = 3.00, 95% confidence interval [CI]: 1.98-4.76; P = 0.007) and cardiopulmonary bypass (OR = 4.09, 95% CI: 2.44-6.85; P = 0.002) were significant risk factors for early mortality. In-hospital and interval surgical reintervention rates were 12% and 13.3%, respectively. Following the primary shunt procedure, the median time to second-stage surgery was 15.5 months (range: 5.0-34.0 months). Conclusion: The findings of this study support those reported in international research regarding the risks associated with mBT shunt surgeries. In particular, preoperative mechanical ventilation and cardiopulmonary bypass were significant risk factors for early mortality.
... 5,6 Various risk factors have been identified as resulting in worse outcomes for patients receiving mBT shunts, including the age and weight of the child at the time of surgery, the size of the shunt, pulmonary atresia with intact ventricular septum (PAIVS) and preoperative shock or acidosis. 5,[7][8][9] The immediate postoperative period following insertion of the mBT shunt is when the patient is most vulnerable. According to Petrucci et al., 33% of deaths in neonates undergoing mBT shunt procedures occurred within 24 hours of surgery, with 75% occurring within the first month. ...
Article
Full-text available
Objectives: A modified Blalock-Taussig (mBT) shunt procedure is a common palliative surgery used to treat infants and children with cyanotic congenital heart disease (CCHD). This study aimed to report the outcomes of infants and children undergoing mBT shunt procedures in Oman. In addition, risk factors associated with early mortality, inter-stage mortality and reintervention were assessed. Methods: This retrospective cohort study was conducted from January 2016 to December 2018 at the National Heart Centre, Muscat, Oman. All paediatric patients with CCHD undergoing mBT shunt procedures as a primary palliative procedure during this period were included. Data were retrieved from electronic hospital records. Kaplan-Meier survival curves were used to describe overall survival. Results: A total of 50 infants and children were included in the study. The in-hospital mortality and inter-stage mortality rates were 10% and 6.7%, respectively. Preoperative mechanical ventilation (odds ratio [OR]: 3.00, 95% confidence interval [CI]: 1.98–4.76; P = 0.007) and cardiopulmonary bypass (OR: 4.09, 95% CI: 2.44–6.85; P = 0.002) were significant risk factors for early mortality. In-hospital and interval surgical reintervention rates were 12% and 13.3%, respectively. Following the primary shunt procedure, the median time to second-stage surgery was 15.5 months (range: 5.0–34.0 months). Conclusion: The findings of this study support those reported in international research regarding the risks associated with mBT shunt surgeries. In particular, preoperative mechanical ventilation and cardiopulmonary bypass were significant risk factors for early mortality. Keywords: Pediatrics; Heart Diseases, congenital; Cardiovascular Surgical Procedures; Modified Blalock-Taussig Procedure; Patient Outcome Assessment; Hospital Mortality; Risk Factors; Oman.
Article
Objectives The optimal management strategy for symptomatic young infants with tetralogy of Fallot (TOF) is yet to be determined. We aimed to evaluate the long-term outcomes of a staged approach with initial shunt palliation followed by complete repair. Methods Between January 1993 and July 2021, 160 children with TOF underwent systemic-pulmonary shunts at our institution, including 65 (41%) neonates. Mean follow-up was 12.3 ± 8.1 years. Results Hospital mortality was 3% (4/160), all occurred in patients with shunt size-to-weight ratio ≥1.2 mm/kg. Composite morbidity, defined as cardiac arrest, postoperative mechanical circulatory support, or unplanned reoperation, occurred in 21% (33/160). On multivariable analysis, shunt size-to-weight ratio ≥1.2 mm/kg and prematurity were independent predictors of composite morbidity. Interstage mortality was 3% (4/156). Limited transannular patch was used in 75% (113/150) of TOF repairs. Actuarial survival at 20-years after shunt was 90% (95% confidence interval [CI]: 79-95%). Actuarial freedom from reinterventions at 20-years after TOF repair was 40% (95% CI: 28-52%). Neonates had comparable composite morbidity, mortality, and late risk of reinterventions as older children. Conclusions Staged repair of TOF in symptomatic young infants results in low mortality but high rates of reinterventions at long-term follow-up. Shunt size-to-weight ratio >1.2 mm/kg is a significant risk factor for mortality and morbidity prior to complete repair. Neonates undergoing shunt insertion have comparable outcomes as older children.
Article
Full-text available
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Article
Historically, the Blalock Taussig (BT) shunt has been an off-pump procedure. For the last two decades, the number of BT shunt operations has come down globally with the adoption of neonatal early corrective surgery. BT shunts are still performed for augmentation of pulmonary arterial (PA) growth or as a part of univentricular palliation. Many infants do not tolerate PA branch clamping while undergoing the graft to PA anastomosis, necessitating institution of cardiopulmonary bypass (CPB). Since the threshold to go on CPB for shunt placement is quite low at most institutions, our technical modification described can avoid deleterious effect of CPB. Our point of interest is to maintain lung perfusion by adopting few principles of off-pump coronary artery bypass surgery.
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Forty-six neonates with various conditions of low pulmonary blood flow received a modified Blalock-Taussig shunt with a polytetrafluoroethylene graft. Ages ranged from 2 to 30 days (mean, 14.1 days). Hospital mortality was 10.9%. Shunt block requiring reoperation occurred in 3 patients. Incremental risk factors for early mortality were found to be restrictive atrial septal defect, univentricular physiology, and postoperative reintervention. It was found that a Blalock-Taussig shunt could be performed in the neonatal period with a predictable outcome. Single-ventricle physiology and restrictive atrial septal defect were the major determinants of outcome in this subgroup.
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This chapter covers palliative operations, including the pulmonary artery band, aortopulmonary shunts (such as the classic and modified Blalock-Taussig shunts, Waterston/Cooley shunt, and Potts shunt), and other procedures. Some procedures that are considered obsolete are also included, so that surgeons whose patients have had these procedures performed in the past can become made aware of them.
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Forty-six neonates with various conditions of low pulmonary blood flow received a modified Blalock-Taussig shunt with a polytetrafluoroethylene graft. Ages ranged from 2 to 30 days (mean, 14.1 days). Hospital mortality was 10.9%. Shunt block requiring reoperation occurred in 3 patients. Incremental risk factors for early mortality were found to be restrictive atrial septal defect, univentricular physiology, and postoperative reintervention. It was found that a Blalock-Taussig shunt could be performed in the neonatal period with a predictable outcome. Single-ventricle physiology and restrictive atrial septal defect were the major determinants of outcome in this subgroup.
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Heretofore there has been no satisfactory treatment for pulmonary stenosis and pulmonary atresia. A "blue" baby with a malformed heart was considered beyond the reach of surgical aid. During the past three months we have operated on 3 children with severe degrees of pulmonary stenosis and each of the patients appears to be greatly benefited. In the second and third cases, in which there was deep persistent cyanosis, the cyanosis has greatly diminished or has disappeared and the general condition of the patients is proportionally improved. The results are sufficiently encouraging to warrant an early report.The operation here reported and the studies leading thereto were undertaken with the conviction that even though the structure of the heart was grossly abnormal, in many instances it might be possible to alter the course of the circulation in such a manner as to lessen the cyanosis and the resultant disability. It is
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In 1945 Blalock and Taussig1 introduced a new surgical procedure for the relief of anoxemia due to pulmonary stenosis or pulmonary atresia. By anastomosing the subclavian or innominate artery to either the right or the left pulmonary artery they have been able to increase the flow of blood to the lungs. Their work is an outstanding contribution to the relief of children whose outlook without aid is hopeless. Sacrifice of the subclavian artery for the anastomosis of its: proximal end to the side of a pulmonary artery is associated with little danger to the circulation of the arm. Use of the innominate artery for such an anastomosis entails the hazard of an inadequate supply of blood to the brain.The possibility of making a direct anastomosis between the aorta and the adjoining pulmonary artery was reviewed. Gross and Hufnagel2 and Blalock and Park3 concluded from their experimental work
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Perioperative advances have led to significant improvements in outcomes after many complex neonatal open heart procedures. Whether similar improvements have been realized for the modified Blalock-Taussig shunt, the most common palliative neonatal closed-heart procedure, is not known. Data were abstracted from The Society of Thoracic Surgeons Congenital Heart Surgery Database (2002 to 2009). Inclusion criteria were all neonates who received a modified Blalock-Taussig shunt with or without cardiopulmonary bypass, and with or without concomitant ligation of a patent ductus arteriosus. Discharge mortality was the primary end point. A composite morbidity end point one or more of the following: postoperative extracorporeal membrane oxygenation, low cardiac output, or unplanned reoperation. Associations with patient and procedural variables were assessed with univariable and multivariable analyses. The inclusion criteria were met by 1273 patients. The discharge mortality rate was 7.2%, and composite morbidity, as defined, was 13.1%. Primary diagnoses were classified as (1) those potentially amenable to biventricular repair (62%), (2) functionally univentricular hearts (22%), and (3) pulmonary atresia with intact ventricular septum (PA/IVS; 14%), and miscellaneous (2%). Discharge mortality stratified by primary diagnoses was PA/IVS (15.6%), functionally univentricular hearts (7.2%), and diagnoses potentially amenable to biventricular repair (5.1%). Need for preoperative ventilatory support, diagnosis of PA/IVS or functionally univentricular hearts, and any weight less than 3 kg, were risk factors for death. Preoperative acidosis or shock (resolved or persistent) and diagnosis of PA/IVS or functionally univentricular hearts were predictors of composite morbidity. Nearly 33% of the deaths occurred within 24 hours postoperatively, and 75% within the first 30 days. The mortality rate after the neonatal modified Blalock-Taussig shunt remains high, particularly for infants weighing less than 3 kg and those with the diagnosis of PA/IVS.
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Factors relating to acute blockage of modified Blalock-Taussig shunts (MBTS) have not been well described in the literature. Our aim was to determine the outcomes in patients early after undergoing MBTS operations and to identify potential risk factors for acute shunt blockage in the early postoperative period. A retrospective study was performed in a tertiary referral congenital cardiac unit. All children who underwent first shunt insertion for cyanotic congenital heart disease during the study period from 2002 to 2006 were included. Seventy-six children underwent first shunt insertion with a median age of 37 days (range 2 days-8 years) and median weight of 3.75 kg (range 2.1-17.2 kg). The shunt sizes varied from 3 to 6 mm. The rate of acute shunt blockage was 11.8% (9/76), all within the first 24 h. There were 3 early deaths (3.9%), none of which were associated with shunt blockage. The main risk factors for blockage were preoperative high hemoglobin, weight less than 3 kg, and duct patency on echocardiogram after surgery. This study identifies that high preoperative hemoglobin, a weight less than 3 kg at operation, and the presence of a patent duct are statistically significant risk factors for shunt blockage in the acute postoperative period. Further work is needed to determine if reduction in preoperative hemoglobin concentration and attempts to reduce postoperative ductal patency may alter the outcome.
Article
The Blalock-Taussig (BT) shunt is an excellent palliative procedure for cyanotic congenital heart defects. We reviewed two techniques of performing the BT shunt, median sternotomy and thoracotomy, in relation to morbidity and mortality. Forty-five modified BT shunts in 41 patients, mean age 93 days (1-1045 days), were performed between January 2002 and October 2004. Twenty-four (53.3%) shunts in 21 (51.2%) patients were performed through thoracotomy and 21 (46.7%) shunts in 20 (48.8%) patients through median sternotomy. One surgeon preferred thoracotomy and the other sternotomy approach irrespective of age/weight or elective/emergency. Thirty-eight (84.4%) cases underwent elective operation and 7 (15.6%) cases were operated as emergencies. In both groups the most frequent diagnosis was complex Tetralogy of Fallot. Postoperative oxygen saturation was same in both groups and there were no significant complications in either group. Patients undergoing BT shunt via median sternotomy approach had longer duration of ventilation (mean 183 h vs. 53 h, P<0.001) and inotropic requirements (33.3% vs. 4.2%, P<0.05) leading to longer intensive care unit stay (mean 9.14 days vs. 3.3 days, P<0.05) and hospital stay (mean 14.59 days vs. 5 days P<0.005). Median sternotomy approach to performing BT shunt seems to carry a higher morbidity than thoracotomy. We recommend a large case series study and longer follow up.
Article
A 6-month-old girl with a diagnosis of double-outlet right ventricle and pulmonary stenosis had a left modified Blalock-Taussig shunt. Chest computed tomography (CT) performed on postoperative day 11 showed good patency of the shunt. However, on postoperative day 16, oxygen saturation suddenly dropped below 40%, and chest CT showed thrombotic occlusion of the shunt. Urgent thrombectomy was performed successfully. Examination of coagulation factors revealed low levels of both the amount and activity of protein C (27% and 31%, respectively). Diagnosis of heterozygous hereditary protein C deficiency was made, and the patient was placed on warfarin. She is currently in good condition.