Preoperative single ventricle function determines early outcome after second-stage palliation of single ventricle heart
Pająk et al. Cardiovascular Ultrasound
Preoperative single ventricle function determines early outcome after second- stage palliation of single ventricle heart
Jacek Pająk 0 3
Michał Buczyński 0 3
Piotr Stanek 2
Grzegorz Zalewski 2
Marek Wites 2
Lesław Szydłowski 1
Bogusław Mazurek 1
Lidia Tomkiewicz-Pająk 4
0 Pediatric Heart Surgery and General Pediatric Surgery Department, Medical University of Warsaw , ul. Żwirki i Wigury 63A, 02-091 Warszawa , Poland
1 Department of Pediatric Cardiology, Medical University of Silesia , Katowice , Poland
2 Pediatric Heart Surgery Department, The Independent Public Clinical Hospital no. 6 of the Medical University of Silesia , Katowice , Poland
3 Pediatric Heart Surgery and General Pediatric Surgery Department, Medical University of Warsaw , ul. Żwirki i Wigury 63A, 02-091 Warszawa , Poland
4 Institute of Cardiology, Jagiellonian University, Medical College and John Paul II Hospital , Krakow , Poland
Background: Second-stage palliation with hemi-Fontan or bidirectional Glenn procedures has improved the outcomes of patients treated for single-ventricle heart disease. The aim of this study was to retrospectively analyze risk factors for death after second-stage palliation of single-ventricle heart and to compare therapeutic results achieved with the hemi-Fontan and bidirectional Glenn procedures. Material and methods: We analyzed 60 patients who had undergone second-stage palliation for single-ventricle heart. Group HF consisted of 23 (38.3%) children who had been operated with the hemi-Fontan method; Group BDG consisted of 37 (61.7%) who had been operated with the bidirectional Glenn method. The analysis focused on 30-day postoperative mortality rates, clinical and echocardiographic data, and early complications. Results: The patients' ages at the time of repair was 33 ± 11.2 weeks; weight was 6.7 ± 1.2 kg. The most common anatomic subtype was hypoplastic left heart syndrome, in 36 (60%) patients. The early mortality rate was 13.3%. Significant preoperative atrioventricular valve regurgitation, single-ventricle heart dysfunction, pneumonia/ sepsis, and arrhythmias were associated with higher mortality rates after second-stage palliation. Multivariate analysis identified significant preoperative single-ventricle heart dysfunction as an independent predictor of early death after second-stage palliation. No differences were found in the analyzed variables after bidirectional Glenn compared with hemi-Fontan procedures. Conclusion: Significant preoperative atrioventricular valve regurgitation, arrhythmias and pneumonia/sepsis are closely correlated with mortality in patients with single-ventricle heart after second-stage palliation. Preoperative significant single-ventricle heart dysfunction is an independent mortality predictor in this group of patients. There are no differences in clinical, echocardiographic data, or outcomes in patients treated with the hemi-Fontan compared with bidirectional Glenn procedures.
Second-stage single-ventricle palliation; Single-ventricle heart; Hemi-Fontan; bidirectional Glenn procedure; Hypoplastic left heart syndrome; Extracellular matrix; CorMatrix
Second-stage palliation, using the hemi-Fontan or
bidirectional Glenn procedures in the surgical treatment of
single-ventricle heart has reduced the complication rate
and improved outcomes after the final stage, i.e. the Fontan
operation. Anatomically, second-stage palliation for
singleventricle heart represents one-half of systemic
venous-topulmonary arterial anastomosis, while hemodynamically it
leads to normalization of the volume load of the single
]. Such an intermittent stage promotes better
tolerance and gradual transition to the hemodynamic model
after the Fontan operation. Second-stage palliation of
single-ventricle heart performed with the hemi-Fontan
method consists of anastomosing the superior vena cava
(SVC) with the pulmonary arteries close to the SVC
insertion to the right atrium, while the SVC insertion is
separated from the right atrial cavity by means of a transverse
patch sutured to the right atrial walls. Such a location of
the incision line, anastomosis and patch suturing lines, and
future scar formation in this region, pose a risk of damaging
the sinus node and/or impulse conduction pathways from
the sinus node. These issues may lead to arrhythmias, a
severe complication, given the post-Fontan operation
circulation physiology [
]. Performing hemi-Fontan as
secondstage palliation necessitates performing the Fontan
operation, using the “lateral tunnel” technique, which
consists of suturing a patch inside the right atrium that directs
flow from the vena cava to the pulmonary arteries. Thus,
hemi-Fontan does not allow for a selection of the Fontan
operation technique to match the anatomy of a defect [
In 2011, we decided to switch our second-stage
palliation surgical technique from the hemi-Fontan to the
bidirectional Glenn. In bidirectional Glenn, the SVC is
anastomosed with the pulmonary arteries at a distance
from the sinus node region and conduction pathways,
an arrangement that would seem to decrease the risk of
arrhythmias developing. However, no reports have been
published that unambiguously favor either of the
methods. Hence, we are our attempting to evaluate
hemi-Fontan and bidirectional Glenn based on our
clinical outcomes. Both in the hemi-Fontan and
bidirectional Glenn technique, achieving a wide anastomosis
between the SVC and the pulmonary arteries may
require using a biological or artificial patch to enlarge the
anastomosed site. Since the beginning of 2013, we have
placed an extracellular matrix (ECM) patch, derived
from porcine small intestinal submucosa [
], in all
children with single-ventricle heart operated for
enlargement of pulmonary artery anastomoses.
The aim of the present study was to retrospectively
analyze risk factors of mortality after second-stage palliation
of single-ventricle heart, and to compare the therapeutic
results achieved with hemi-Fontan and bidirectional
We conducted a retrospective review of all the patients
who had undergone second-stage palliation for
singleventricle heart in the Pediatric Heart Surgery Department
(University School of Medicine in Katowice, Poland)
between 2003 and 2015. The study protocol was approved
by the local ethics committee. Depending on the method
of surgical treatment, the patients were assigned to one of
two groups. Group HF consisted of 23 (38.3%) children, in
whom second-stage palliation had been performed using
the hemi-Fontan method in the years 2003–2011. Group
BDG consisted of 37 (61.7%) children who had been
treated in the years 2011–2015, with the bidirectional
Glenn procedure. In this group, 15 (40.5%) patients had a
direct end-to-side anastomosis made between the SVC
and the right pulmonary artery, while the remaining 22
(59.5%) patients had the SVC and right pulmonary
artery anastomosis extended by use of an ECM patch
(CorMatrix®; Cardiovascular, Inc., Roswell GA, USA).
Patient demographics, clinical characteristics, imaging,
operative reports, hospital records, and clinical reports
were collected, and a retrospective analysis of the data
In all the patients, anatomical details were determined,
and the children were deemed qualified for surgical
treatment based on echocardiographic findings.
Echocardiograms were interpreted by two readers, who assessed
the single-ventricle morphology and function and
atrioventricular valve function. The single-ventricle function
was assessed semi-quantitatively according to the
following scale: 1, good; 2, fair; 3, decreased, and 4, poor [
Significant impairment of the single-ventricle heart
function was defined as a score of more than fair.
Semi-quantitative assessment was also used in evaluating
valvular competence, the scale being 0, none; 1, mild; 2,
moderate; 3, severe [
]. Significant regurgitation was
defined as a score more than mild. The examinations were
performed before operation and on day 2 postoperatively.
The analyses performed in the two groups included
postoperative 30-day mortality rates and these variables:
anatomy of the defect; age; body mass; aortic clamp
time; oxygen arterial blood saturation (Sat O2) on day 1,
3 and 5 postoperatively; pneumonia or sepsis;
atrioventricular valve regurgitation (AVVR); single-ventricle
function; arrhythmias; intubation time; duration of
hospitalization; and relations between these variables
and their effect on the outcomes.
The diagnosis of a clinically significant arrhythmia in
the perioperative period was based on the Cardiosurgical
Postoperative Intensive Care Unit monitoring system and
a review of all available electrocardiograms. “Arrhythmia”
was defined as a rhythm requiring treatment with an
antiarrhythmic medication or pacing, or led to
To assess differences between the groups in qualitative
data, we employed the chi-square test or the Fisher’s
exact test, whereas quantitative data were evaluated with
the t-Student test or Mann-Whitney test. Correlation of
quantitative data was analyzed by the Spearman’s
correlation coefficient (rs); for qualitative data, we employed
the chi-square or the Fisher’s exact test. The stepwise
logistic regression was used to determine factors affecting
postoperative mortality rates.
In all patients in both groups, the procedure was
performed through a median sternotomy. The ascending
aorta was cannulated. In 10 (27.0%) patients in Group
BDG, two venous cannulas were inserted, one into the
right atrium and another high in the SVC. In these
patients, a direct SVC-right pulmonary artery anastomosis
was performed with the patient in moderate hypothermia
(approximately 32o C). In the remaining children from
both groups, a single venous cannula was inserted into the
right atrium, and the procedure was performed in deep
hypothermia (approximately 18o C) with low flow (cardiac
output approx. 50 ml/kg) or with cardiac arrest; crystalline
cardioplegia was administered.
In Group HF, all children had a hemi-Fontan
anastomosis constructed between the SVC and the pulmonary
arteries, and an oval polytetrafluorethylene patch was
sutured below the SVC outlet to the right atrium, which
separated the SVC outlet from the remaining RA. The
anterior part of the SVC-PAs anastomosis was enlarged
by use of a homogenous pulmonary artery patch.
In Group BDG, 5 (13.5%) children had a direct
bidirectional Glenn anastomosis performed in deep
hypothermia with low flow. The remaining 22 patients
(59.5%) had a modified Norwood I procedure (aortic
arch ECM patch reconstruction and bilateral pulmonary
artery banding), in which the pulmonary arteries were
dissected from the main pulmonary artery trunk, the
stumps were proximally closed with sutures, and the
junction between the pulmonary arteries and SVC was
reconstructed with an ECM (CorMatrix®) tube larger in
diameter than the pulmonary artery diameter (Fig. 1).
No patient had a surgical correction because of
insufficient tricuspid valve.
Postoperatively, all the patients were hospitalized in
the Cardiosurgical Postoperative Intensive Care Unit. All
patients received heparin in the early postoperative
period, then antiplatelet medication until the Fontan
operation was performed.
Patients characteristics are reported in Tables 1 and 2.
All children with HLHS operated on in the years
2003–2013 received the Norwood I procedure as
modified by Sano et al. [
] as the first-stage
operation (part of Group HF). Since 2013, we have
routinely used our modification of the Norwood
procedure in the first-stage of HLHS treatment; the
modification consists of reconstructing the aortic arch
with an ECM patch and in bilateral pulmonary
arteries banding (part of Group BDG). Patients with
diagnoses other than HLHS had made earlier main
pulmonary artery banding or systemic – pulmonary
anastomosis as a first stage operation or they required
Table 1 illustrates that Group BDG patients were
significantly older than Group HF patients at the time of
operation [36 weeks (range 19–72) vs. 28 weeks (range
10–42); p = 0.03]. Otherwise, no significant differences
were noted in body mass, intubation time, aortic clamp
time, arterial blood saturation, duration of hospitalization,
arrhythmias, pneumonia/sepsis, mortality rate, AVVR, or
systemic ventricular function.
Risk factors and mortality (Table 2)
Postoperative arrhythmias were recorded in 9 of the 60
(15%) children, 5 (22%) in Group HF; 3 (13.0%) of these
children had slow sinus rhythm, and 2 (9%) had sinus
bradycardia. Among the 4 (11%) in Group BDG, 1 (3%)
AVVR atrioventricular valve regurgitation, SV single ventricle
had slow sinus rhythm, 1 (3%) had sinus bradycardia,
and 2 (5%) had tachyarrhytmias with a moderate
reaction to pharmacotherapy.
were intubated significantly longer than those who did
not develop postoperative pneumonia/sepsis, both in
Group HF (p = 0.025) and in Group BDG (p = 0.009).
Pneumonia/sepsis developed in 9 of the 60 children
(15.0%), 5 of 23 (22%) in Group HF and 4 of 37 (11%) in
Group BDG, a statistically insignificant difference. The
children who developed postoperative pneumonia/sepsis
Pre-and postoperative A-V valve regurgitation and
singleventricle heart function
Significant preoperative AVVR (Grade 2 or 3) was
present in 12 (20%) of the 60 investigated patients, and
postoperative AVVR was present in 7 (12%).
In Group HF, significant preoperative AVVR was
present in 5 of 23 (22%) patients, of whom 4 (80%) had
significant single-ventricle dysfunction. AVVR developed
in 3 (13%) children with HLHS and 2 (8%) patients with
unbalanced atrioventricular septal defect (UAVSD). Two
(9%) children with HLHS had postoperative
improvement of atrioventricular valve function, whereas 3 (13%)
with this defect had no improvement (and died) - 2 (9%)
of them developed arrhythmias, and 1 (4%) had fatal
In Group BDG, 7 of 37 (19%) children had significant
AVVR, shown in preoperative echocardiography; 5 (14%)
had HLHS and 2 (5%) had UAVSD. Six (86%) patients
with significant AVVR also had significant
singleventricle dysfunction. After bidirectional Glenn,
echocardiography in 3 (8%) patients with HLHS revealed
improvement in tricuspid valve competence, whereas no
improvement was seen in the other 4 (11%); 2 (5%) of
these patients developed arrhythmias, and 2 (5%)
developed pneumonia/sepsis; these four children died.
The rates of postoperative single-ventricle heart
function of grades 1–2 and 3–4 were similar in the
Four of 23 (17.4%) children in Group HF died. Three
(75%) had significant atrioventricular valve regurgitation
before and after operation. Postoperatively, 2 of the
patients (50%) developed arrhythmias – sinus bradycardia
in 1 (25%) and slow sinus heart rhythm in the other
(25%). None of the deceased children presented with
tachyarrhythmia. One (25%) deceased child, with
significant atrioventricular valve regurgitation, developed
sepsis. In 1 (25%) child, sinus bradycardia occurred, and the
patient died due to low cardiac output despite effective
atrial pacing. The deceased patients in Group HF had
significantly more frequent arrhythmias (75% vs. 11%;
p = 0.02) and AVVR (75% vs. 11%; p = 0.02) than did
Four for 37 (10.8%) children from Group BDG died.
All had significant atrioventricular valve regurgitation.
Two (50%) of the children also developed
supraventricular tachyarrhythmia, and 2 (50%) had pneumonia/sepsis.
The deceased patients In Group BDG had significantly
more frequent arrhythmias (50% vs. 6%; p = 0.05), more
frequent significant AVVR (100% vs. 9%; p < 0.001) and
more frequent pneumonia/sepsis (50% vs. 6%; p = 0.05)
than did the survivors.
Univariate and multivariate analysis of risk factors and death
Univariate analysis was performed to identify risk factors
for death by patient characteristics and clinical and
echocardiographic data (Table 3). Preoperative
singleventricle heart dysfunction (grade 3–4; significant
impairment); preoperative clinically significant AVVR
(grade 2–3; worse than mild); arrhythmias; and sepsis
were associated with death. Multivariate analysis then
was performed, with logistic regression in a model that
took statistically significant preoperative variables from
the univariate analysis. In the multivariate analysis,
significant preoperative single-ventricle heart dysfunction
was the only independent prognostic risk factor for
death in second-stage palliation of single-ventricle heart
anatomy (odds ratio 4.7; p < 0.001) (Fig. 2).
Our study showed that clinically significant preoperative
AVVR, preoperative single-ventricle dysfunction,
pneumonia/sepsis, and arrhythmias were associated with
increased mortality in patients with single-ventricle
heart disease who underwent second-stage palliation.
Only significant preoperative single-ventricle
dysfunction was an independent prognostic risk factor. We
did not find significant differences in clinical data,
echocardiographic findings, or outcomes of patients
treated with the hemi-Fontan compared with the
bidirectional Glenn technique.
The mortality rate in our patients was higher than
rates reported by centers treating larger numbers of
]. This difference might be due to greater
patient complexity in our population, as we aggressively
accept high-risk patients. In recent years, the mortality
rate in our patients from Group BDG has decreased
compared with the rate in Group HF, even though
Group BDG included older children with more complex
defects than did Group I. A high percentage of our
patients (20%) had significant AVVR, which has been
reported to have a high perioperative risk [
emphasize that, except for one patient with complex
heterotaxy syndrome, all children in our study who died
had significant AVVR preoperatively; the significant
AVVR persisted after operation, and the children also
developed arrhythmias and/or pneumonia/sepsis.
Significant AVVR in our patients was due to
dysfunction of the very valve and/or dysfunction of the
singleventricle. Disturbances of the structure/competence of
the valve are most commonly associated with the
anatomical background of the single ventricle heart and
usually appear as unbalanced forms of common
atrioventricular canal, as well as in heterotaxy syndrome. A
] has shown that even in the absence of
associated defects and physiologic derangements, UAVSD
confers risk on patients with single-ventricle heart.
Mortality rates in these patients are high, regardless of
whether valvuloplasty is performed in parallel with the
second-stage palliation of single-ventricle heart [
view of problems inherent in A-V valvuloplasty and the
unimpressive results, we have not attempted this
procedure. In cases of AVVR combined with ventricular
dysfunction, we tried to perform stage II palliation at an
earlier age (about 4 months of life), so the volume load
of the single-ventricle could normalize earlier [
earlier operation, AVV competence was improved in
children with HLHS but not in those with UAVSD, a
result that is concordant with those of others .
In this study, significant single-ventricle dysfunction
was an independent prognostic risk factor in patients
with single-ventricle heart after second-stage palliation.
Dysfunction of the single ventricle determines the
occurrence of other complications that increase the risk of
death in the early postoperative period. Bharucha et al.
] demonstrated that right ventricular mechanical
dyssynchrony and inhomogeneous contraction were worse
in patients with clinically important tricuspid
regurgitation and HLHS. Ventricular dysfunction leads to
atrioventricular regurgitation, which in time results in
progressive circulatory insufficiency. Patients with this
insufficiency are susceptible to infections and often
are operated on after numerous infectious episodes,
when they are colonized by pathological bacterial and
Changing the surgical technique from the
hemiFontan to bidirectional Glenn procedure did not
significantly affect the prevalence of postoperative arrhythmias
in our cohort. Similarly, as in other reports [
sinus bradycardia and slow sinus rhythm were the
predominant postoperative cardiac rhythm abnormalities
after second-stage palliation of single-ventricle heart. In
2 patients, supraventricular tachyarrhythmia developed
after the bidirectional Glenn procedure, a complication
that we believe has not been described. In each case of
second-stage single-ventricle palliation, interatrial
communication was enlarged surgically. On the one hand,
such management allows for achieving wide interatrial
communication, whereas on the other, it poses a threat
of damaging the impulse conduction pathways between
the sinus node and the sinoatrial node. Love et al. 
showed that the atriotomy, right atrial free-wall scars,
and atrial septal scars were predictors of
tachyarrhythmias in patients after congenital heart diseases
operations. Our patients with tachyarrhythmias had both
atriotomy and atrioseptostomy, which we feel may have
For reconstruction of the pulmonary arteries and
widening the SVC-pulmonary arteries anastomoses
we have used an ECM (CorMatrix®) patch. This
material has proven safe in reconstruction of
lowpressure vessels. However, Hibino et al. [
observed that at a mean follow-up of 9.7 months, 8 of
10 patients who underwent central pulmonary artery
reconstruction with CorMatrix® tube had progressive
significant stenosis. To avoid this complication, we
used oversized anastomoses between the pulmonary
arteries and the SVC.
There are limitations of this study. First, the number
of the patients was small, although the study does have
the advantage of uniform management in a single center.
Second, the retrospective nature of the study could have
introduced bias that affected comparisons between
treatment groups. A prospective, randomized study of
second-stage palliation (hemi-Fontan vs bidirectional
Glenn procedure) of single-ventricle heart disease is
needed. Third, in all patients, the ventricular function
was evaluated semi-quantitatively. All patients were
qualified to stage II on the base of echocardiographic
examination; in some examinations it was impossible to
visualize the size of all pulmonary arteries; thus,
unfortunately, we could not include this important
measurement in our analysis.
Significant preoperative atrioventricular valve
regurgitation, arrhythmias and sepsis are closely correlated with
mortality in patients with single-ventricle heart disease
after second-stage surgical palliation. Preoperative
significant single-ventricle dysfunction is an important
problem that has not been overcome by staged repair
and has the highest impact on the mortality rate after
second-stage surgical palliation. The bidirectional Glenn
technique in surgical treatment of single-ventricle heart
does not have a lower the incidence of early
complications than does the hemi-Fontan operation.
AVVR: Atrioventricular valve regurgitation; DILV: Double inlet left ventricle;
ECM: Extracellular matrix; HLHS: Hypoplastic left heart syndrome;
SatO2: Oxygen arterial blood saturation; SVC: Superior vena cava;
TA: Tricuspid atresia; UAVSD: Unbalanced atrioventricular septal defect
We thank to Dr. H. Stanuch for statistical analysis.
Availability of data and materials
The datasets used and/or analyzed during the study are available from the
corresponding author on reasonable request.
JP contributed to study conception and design, acquisition of data, analysis
and interpretation of data, drafting and critical revision of the manuscript.
MB participated in the design of the study, collection of data, and drafting
of the manuscript. PS participated in analysis and interpretation of data and
drafting the manuscript. GZ participated in collection and interpretation of
the data. MW contributed to study conception, design and to acquisition
of data. LS contributed to study conception and design, critical revision for
important intellectual content, and final approval of the version to be published.
BM collected data, analyzed and interpreted data, and critically revised the
manuscript. LT-P contributed to acquisition of data, analysis and interpretation of
data, and critical revision of the manuscript. All authors read and approved the
Ethics approval and consent to participate
As this was a retrospective study based on existing patient data, individual
informed consent was not required. The study was nevertheless registered
and approved by the local ethics committee (KNW/0022/KB/100/16).
Consent for publication
All authors read and approved the final manuscript.
The authors declare that they have no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
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