1. ORIGINAL ARTICLE
Perinatal course of Ebstein’s anomaly and tricuspid valve dysplasia
in the fetus
Javier J. Lasa1,2*, Zhi-Yun Tian1,2
, Rong Guo1
and Jack Rychik1,2
1
Division of Cardiology, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
2
University of Pennsylvania School of Medicine, Philadelphia, PA, USA
*Correspondence to: Javier J. Lasa. E-mail: lasaj@email.chop.edu
ABSTRACT
Objective We sought to better define echocardiographic predictors of perinatal mortality in fetuses with Ebstein’s
anomaly (EA) or tricuspid valve dysplasia (TVD).
Method Parameters included measured chamber size, the presence of hydrops, and Doppler recordings of the left
ventricular (LV) myocardial performance index (MPI).
Results Between 1 January 2000 and 31 December 2008, 21 fetuses were diagnosed with either EA (17) or TVD (4). Five
fetuses were lost to follow-up, and 12 of 16 fetuses were born live (75%). Survivors were found to have smaller right
atrial area index scores when compared with non-survivors (1.025 Æ 0312 vs 1.502 Æ 0.105, respectively, p = 0.013) and
were less likely to present with hydrops (0% survivors vs 75% of non-survivors, p < 0.01). LV MPI sub-analysis revealed
a shorter combined isovolemic contraction and relaxation time for non-survivors compared wth survivors
(46.5 Æ 8.2 ms vs 82.3 Æ 21.2 ms, respectively, p = 0.004) although no difference was observed for LV ejection times or
overall LV MPI between survivors and non-survivors.
Conclusion Physiologic analysis of left ventricular function via the LV Tei index and its component measurements
demonstrates potentially novel insights into hemodynamic derangements and their association with outcomes in
patients with EA/TVD. © 2012 John Wiley & Sons, Ltd.
Funding Sources: None
Conflicts of interest: None declared
INTRODUCTION
Ebstein’s anomaly (EA) and tricuspid valve dysplasia (TVD) are
rare disorders of the tricuspid valve frequently associated with
severe tricuspid valve regurgitation and cardiovascular
compromise when diagnosed in utero.1–7
Both defects are also
associated with extremely high perinatal mortality rates, which
range from 69% to 85% in recent series.8–13
Fetal
echocardiography has advanced our understanding of perinatal
physiology although continued challenges exist in predicting
outcomes for this high-risk and heterogeneous patient
population. Efforts have been made to identify physiologic
factors of most prognostic significance in prenatally diagnosed
tricuspid valve abnormalities. In particular, right ventricular
dilation and myocardial dysplasia with subsequent changes in
left ventricular loading conditions have been proposed as
predictors of worse outcomes in fetuses diagnosed with EA and
TVD.11
Altered cerebral vascular resistance has also been
postulated as an associated hemodynamic sequela observed in
fetuses with both right and left heart lesions.10,14
Our study
aimed to investigate the physiologic and anatomic changes in
the fetus with EA and TVD during fetal life by focusing on the
impact of altered ventricular geometry, ventricular function,
and cerebral perfusion on perinatal mortality.
METHODS
Cases were identified through the Children’s Hospital of
Philadelphia Fetal Heart Program database and were diagnosed
with either EA or TVD in utero between January 2000 and
January 2008. EA was defined as a primary defect in tricuspid
valve delamination with various degrees of inferior displacement
from the atrioventricular valve annulus and associated tricuspid
valve and right ventricular dysplasia. TVD was defined as a
primary defect in tricuspid valve leaflet morphology with normal
atrioventricular valve proximal attachments and abnormal
Prenatal Diagnosis 2012, 32, 245–251 © 2012 John Wiley & Sons, Ltd.
DOI: 10.1002/pd.2939

2. tricuspid valve leaflet coaptation. Fetal echocardiograms were
reviewed with blinding to subsequent outcome. Fetuses with
complex anomalies including congenitally corrected
transposition of the great arteries with associated EA, or
identifiable extra-cardiac malformations (e.g. twin–twin
transfusion recipients, congenital diaphragmatic hernia), and
those not followed at our institution were excluded.
Anatomic measurements were obtained from the level of the
four-chamber view with cross-sectional areas of each
individual chamber obtained at end diastole with tricuspid
valve closure. The cardiothoracic area ratio was calculated by
dividing the epicardial circumference of the heart by the
internal thoracic circumference. The right atrial (RA) area
index (Celermajer index3
) was calculated by dividing the traced
RA area by the combined traced areas of the functional right
ventricle (area distal to the tricuspid valve coaptation plane),
left atrium, and left ventricle. Fetal Doppler recordings were
assessed offline and included pulsed-wave determinations of
blood flow velocities in the umbilical artery (UA), middle
cerebral artery (MCA), as well as across the mitral and aortic
valve for the purposes of calculating LV myocardial
performance index (MPI). The MPI, also known as the Tei
index, was calculated by dividing the combined LV isovolumic
contraction and relaxation times (as measured by the time
interval between the mitral valve opening and closure minus
the aortic ejection time) by the ejection time across the aortic
valve. Pulsatility indices were computed from velocities in both
UA and MCA by dividing the difference in peak systolic velocity
and end-diastolic velocity by the mean velocity. The presence
of antegrade flow across the pulmonary valve was also
evaluated in all fetuses via color Doppler interrogation.
All continuous Doppler measurements were expressed as
mean +/À standard deviation, or median and range where
appropriate. Univariate analysis was performed initially and
followed by stepwise logistic regression. Exact Wilcoxon two-
sample tests were used to compare mean echocardiographic
values, whereas Fishers’ exact test was used to compare
categorical variables. A p-value of <0.05 was considered
statistically significant.
RESULTS
Between 1 October 2000 and 1 January 2010, a total of 21
fetuses were referred for suspected congenital heart disease
and diagnosed with either EA (17) or TVD (4). All had severe
tricuspid regurgitation; 12 (57%) had associated pulmonary
atresia. Demographic and clinical data for these patients are
outlined in Table 1. The median gestational age at the time of
diagnosis was 25 weeks (range 17–37 weeks). Maternal age
ranged from 22 to 39 years (median 29.3 years). In 10 of 21
patients, multiple echocardiograms were performed, with a
range of 2 to 7 studies per patient and a median time from
initial diagnosis to final fetal echocardiogram of 11 weeks.
Five fetuses continued care elsewhere and were lost to
follow-up after initial evaluation; 12 of 16 fetuses were born
live (75%). Pregnancies were terminated in 2 out of 16 cases
(13%). An additional 2 out of 16 pregnancies (13%)
experienced intrauterine fetal demise. Among fetuses
surviving to birth, 8 of 12 (67%) survived to 3 months of
age, resulting in an overall neonatal survival of rate of 50%
(8 of 16), or 57% if elective terminations are excluded on
an intention-to-treat basis. Of survivors to term, only 6 of
12 (50%) underwent surgical or catheter-based intervention
during the first 3 months of life. Four of the six survivors to
term underwent aorto-pulmonary shunt placement in the
neonatal period (three modified Blalock–Taussig shunts, one
central shunt), with an additional survivor undergoing patent
ductus arteriosus stenting and the final survivor requiring
modified Starnes palliation. None of the six survivors were
found to have hydrops on prenatal evaluation and 4 of 6
(67%) survived to 3 months of age.
Hydrops fetalis was diagnosed in 3 of 16 fetuses (19%), with 2
of 3 (67%) experiencing intrauterine fetal demise and one
pregnancy terminated early. All fetuses with hydrops had EA.
Survival to birth
Echocardiographically assessed anatomic and physiologic
predictors of live birth are outlined in Table 2. Pulsatility index
ratios and LV MPIs (Tei indices) were not available for two
patients on retrospective review. When including early
terminations among prenatal non-survivors, neither
cardiothoracic area ratio, Tei index, or pulsatility index ratio
(UA/MCA) were found to be significantly different between
survivors and non-survivors. However, survivors were found
to have smaller RA area index scores when compared with
non-survivors. Additionally, the presence of hydrops in utero
was a significant predictor of death before term with hydrops
observed in 75% of non-survivors, while none of the survivors
were found to have hydrops (p < 0.01) (Table 3).
Further subanalysis of Tei indices revealed a shorter combined
isovolemic contraction and relaxation time for non-survivors
compared with survivors (46.5Æ 8.2 ms vs 82.3 Æ 21.2ms,
respectively, p = 0.004) but no statistically significant difference
for LV ejection times between non-survivors and survivors
(190.2Æ 28.2ms vs 206.2Æ 74.5ms, respectively, p = 0.73).
Two of 4 non-survivors (50%) were found to have absent
flow across the pulmonary valve. Yet in survivors to term, 8 of
12 (66%) were found to have absent antegrade flow. In
addition, all cases of retrograde flow (i.e. continuous
pulmonary regurgitation) were observed in survivors to term.
Survival through infancy (3 months of age)
When assessing similar echocardiographic variables for
survival to hospital discharge and beyond 3 months of age,
similar findings were observed with no statistically significant
differences observed between survivors and non-survivors for
cardiothoracic area ratio, LV MPI (Tei index), or pulsatility
index ratio (UA/MCA).
J. J. Lasa et al.246
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3. The RA area index continued to remain significantly associated
with survival to 3 months of age as survivors had smaller indices
compared with non-survivors (0.921 Æ 0.267 vs 1.368Æ 0.265,
respectively, p = 0.01). No significant association was observed
between the presence of hydrops and death before 3 months of
age although three of eight non-surviving fetuses were found to
have associated hydrops and none of the eight survivors
(p = 0.2). Similar analyses were utilized to predict hydrops,
mortality at term, and mortality at 3 months of age, and no
significant predictors were observed amongst the echocardiogra-
phically assessed anatomic and physiologic variables when using
both mean and last echocardiographic values.
DISCUSSION
Outcomes of fetuses with EA or TVD were improved in
our study when compared with previously published
reports.1,8,11–13
Approximately 75% of fetuses survived to term
with survival approaching 85% when terminations were
excluded, whereas previously published survival rates at
1 month of age ranged from 17% to 40% when terminations
were excluded.1,8,12
Referral bias towards more severe cases
may have affected published outcomes in the past as the
majority of referred cases were perhaps more easily
distinguishable upon imaging. We theorize that improved
ultrasound screening technology and a heightened awareness
of right heart structural defects by the maternal–fetal medicine
community have led to a more normalized distribution of
disease in our current investigation.
Nevertheless, EA and TVD in the fetus still exhibit high
mortality in comparison to other forms of congenital heart
disease. In our current series, RA dilation and expansion of
the atrialized portion of the right ventricle were found to
be highly associated with mortality, as described in previous
reports.1,2,12,13,15,16
The increased RA area index results from
Table 1 Demographic and clinical data summary
Case
GA (weeks) at
diagnosis
Primary TV
diagnosis Additional findings
Fetal
echocardiograms
GA (weeks) at last fetal
echocardiogram Outcome
1 17 EA Uhl’s anomaly,
hydrops fetalis
1 17 Aborted
2 19 EA 7 36 Live born, death at
2 h
3 20 EA 1 20 Aborted
4 20 EA Atrial flutter 7 34 Live born, death at
1 month
5 21 EA 5 28 Alive
6 22 EA 3 35 Alive
7 22 EA Williams syndrome 5 36 Alive
8 23 EA BAV, aortic arch
hypoplasia
4 35 Alive
9 24 EA 1 24 LTF
10 24 EA 1 24 LTF
11 25 TV dysplasia 1 25 LTF
12 26 EA 4 38 Alive
13 27 EA Hydrops fetalis 2 28 IUFD
14 28 TV dysplasia 1 28 LTF
15 29 EA Hydrops fetalis 1 29 LTF
16 29 EA 1 29 Live born, death at
5 months
17 30 TV dysplasia 4 39 Alive
18 32 EA Hydrops fetalis 1 32 IUFD
19 34 EA Agenesis of corpus
callosum
2 36 Live born, death at
1 week
20 36 TV dysplasia 1 36 Alive
21 37 EA 1 37 Live born, death at
2 months
GA, gestational age; TV, tricuspid valve; EA, Ebstein’s anomaly; BAV, bicuspid aortic valve; CNS, central nervous system; IUFD, intrauterine fetal demise; DOL, day of life; LTF,
lost to follow-up.
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4. pathologic volume loading of the right atrium in the setting
of tricuspid regurgitation, ultimately related to the underlying
tricuspid valve abnormality. Yet, additional measures of
overall heart dilation, in particular the cardiothoracic area
ratio, failed to demonstrate any correlation with mortality
in our study. Additional factors, perhaps the impact of severe
disproportion between the right and left sides of the heart
and the potential negative ventriculo–ventricular interactions
may therefore contribute to the clinical outcome in this
population. Hydrops fetalis was found to be associated with
increased mortality, even when excluding the early
termination. In addition, hydropic fetuses were found to
have significantly higher pulsatility index ratios (UA/MCA)
when utilizing all echocardiographic values in a mixed model
(p = 0.03), suggesting that hydrops is associated with
alterations in the ratio of umbilical to cerebrovascular
resistance, which may indirectly reflect decreased cardiac
output.
The absence of antegrade flow across the pulmonary valve
has been postulated as a marker of severity of disease in
post-natal evaluations of EA and TVD.12
Current
understanding of fetal physiology would suggest that only
13% to 21% of antegrade pulmonary blood flow returns to
the left atrium with the remainder shunting across the patent
ductus arteriosus to supply the systemic circulation.17
Antegrade pulmonary blood flow in the fetus therefore
contributes a small percentage of total volume to left
ventricular loading. We found no significant difference
between survivors to term and non-survivors with regards
to presence of antegrade pulmonary blood flow. In addition,
all cases of retrograde flow (i.e. continuous pulmonary
regurgitation) were observed in survivors to term. Our
findings differ from prior reports and highlight the difference
between fetal and post-natal evaluations of patients with EA
and TVD.
The MPI (Tei index) is a well-described ventricular geometry
and heart rate independent measure of global myocardial
performance, with higher values reflecting worse function.18,19
Although not statistically significant, the LV MPI was lower for
non-survivors compared with survivors (p = 0.06) in our study.
Prior studies have demonstrated the contrary finding, with
higher LV Tei indices in EA and TVD fetuses when compared
with controls. In addition, non-survivors have also been found
to have higher LV Tei indices when compared with survivors.10,11
Table 2 Predictors of live birth among 16 fetuses with Ebstein’s anomaly or tricuspid valve dysplasia
Variablea
Survive to birth, n = 12/16% (N) Death before birth,b
n = 4/16% (N) p-value
Cardiothoracic area ratio 0.516 Æ 0.124 0.545 Æ 0.102 0.45
RA area index 1.025 Æ 0.312 1.502 Æ 0.105 0.013
<1 5 (31%) 0 (0%) 0.25
≥1 7 (44%) 4 (25%)
UA pulsatility index 1.195 Æ 0.45 1.353 Æ 0.168 0.51
MCA pulsatility index 1.932 Æ 0.59 2.027 Æ 0.813 0.81
UA/MCA pulsatility index ratio 1.125 Æ 0.587 1.519 Æ 0.654 0.37
<1 4 (25%) 1 (6%) 1.00
≥1 6 (38%) 3 (19%)
LV Tei index 0.457 Æ 0.168 0.252 Æ 0.076 0.06
Combined mitral isovolumic time (ms) 82.3 Æ 21.2 46.5 Æ 8.2 0.004
Aortic ejection time (ms) 206.2 Æ 74.5 190.2 Æ 28.2 0.73
Hydrops fetalis
Absent 12 (75%) 1 (6%) <0.01
Present 0 (0%) 3 (19%)
RA, right atrial; UA, umbilical artery; MCA, middle cerebral artery; LV, left ventricular.
a
Last fetal echocardiogram value used for comparison.
b
Terminations included.
Table 3 Mixed model of fetuses with hydrops demonstrating effect
on umbilical artery (UA)/middle cerebral artery (MCA) pulsatility
index (PI) ratio and left ventricular (LV) Tei index in patients with
Ebstein’s anomaly or tricuspid valve dysplasia. Fetuses without
hydrops were found to have lower UA/MCA PI ratio’s and lower
LV Tei indices (as indicated by negative value) when compared to
patients with hydrops
Variable Estimate Standard error p-value
UA/MCA pulsatility index ratio À1.10 0.453 0.03
LV Tei Index À0.06 0.472 0.90
J. J. Lasa et al.248
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5. A
B
C
Figure 1 (A) Fetal echocardiogram four-chamber still image in a 20-week gestation fetus with Ebstein’s anomaly demonstrating severe right
atrial and right ventricular dilation, diminutive left atrium, and compressed left ventricular chamber. (B) Four-chamber color Doppler
interrogation demonstrating limited filling of the LV relative to the RV. (C) Four-chamber color Doppler interrogation demonstrating the severe
degree of TR associated with Ebstein’s anomaly
Ebstein’s anomaly and tricuspid valve dysplasia in the fetus 249
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6. A proposed mechanism for our unexpected finding relates to the
impact of right ventricular dilation and dyskinesis on left
ventricular filling mechanics and preload. Marked RA dilation
due to severe tricuspid regurgitation can compress the left-sided
structures. Right ventricular atrialization can also lead to altered
LV mechanics by thinning of the ventricular septal. Yet,
controversy exists in the literature regarding the significance of
left ventricular preload in outcomes for this group of patients.
Several investigations testing the Tei index against acute changes
in loading conditions have demonstrated a significant
correlation with diminished preload.18,19,22
However, these
animal experiments were performed in the post-natal
physiological state in subjects with normal intracardiac anatomy
and presumed normal myocardial substrates. Another published
series of eight fetuses demonstrated worse outcomes for fetuses
with EA with diminished left ventricular output and a smaller
fossa ovalis.13
However, in another larger series, no significant
difference in size of fossa ovalis or left ventricular output was
observed between survivors and non-survivors.1,11
In addition,
recent genetic investigations have demonstrated an association
between EA, left ventricular noncompaction, and mutations in
MYH7 encoding -myosin heavy chain.20,21
These negative
ventricular–ventricular interactions with potential LV
myocardial abnormalities may combine to negatively affect left
ventricular systolic function as well as diastolic filling, leading
to decreased LV preload with secondary effects on total
isovolemic and ejection times. We therefore speculate that
reduced LV preload in addition to the negative RV–LV interaction
both combine to decrease total isovolemic times out of
proportion to ejection times, thereby lowering the Tei index for
this population of fetuses. This phenomenon is further suggested
by the echocardiographic appearance that we have noted in
some of our fetuses in which the LV cavity appears small and
under-filled (Figure 1A–C). As expected with decreased preload,
ejection times in non-survivors were found to be shorter in our
study although the difference did not reach statistical
significance. However, our study is the first to demonstrate
disproportionately lower isovolemic contraction and relaxation
times for non-survivors when compared with survivors.
Subanalysis of the components of the LV Tei index, as
physiological indicators of impaired LV filling, may represent a
novel and potentially valuable echocardiographic variable of
prognostic significance in EA and TVD and may be worthy of
further investigation.
There are several limitations associated with our retrospective
investigation. A relatively large percentage of fetuses (24%)
initially evaluated at our center were subsequently followed
elsewhere and lost to detailed follow-up. Because of our center’s
role as a referral center, it is possible that referral bias was
present although this would likely have led to a higher numbers
of patients with more severe disease (more obvious RA dilation,
severe tricuspid regurgitation, etc.) and subsequently elevated
prenatal mortality rate. However, our results demonstrate
improved outcomes in comparison to prior studies.
CONCLUSION
In summary, fetal disorders of the tricuspid valve remain a
source of increased perinatal mortality. Traditional
measurements of RA dilation, such as the RA area index, and
the presence of hydrops remain significantly associated with
mortality at term. Physiologic analysis of left ventricular
function in the population via the LV Tei index has shown
novel insights into hemodynamic derangements and their
association with outcomes. Study of this unique anomaly
remains a challenge because of the relatively small number of
patients seen at any one center. As small series such as ours
continue to emerge, it appears that there is striking
heterogeneity as to the clinical manifestations of EA and TVD
with complex and variable physiological conditions perhaps
specific to individual patients with this class of disorder. EA
and TVD are anomalies that will benefit from the development
of a multicenter registry in order to better understand the
natural and ‘unnatural’ history, thereby improving prognosis
and aiding in the creation of targeted treatment strategies.
WHAT’S ALREADY KNOWN ABOUT THIS TOPIC?
• Ebstein’s anomaly (EA) and tricuspid valve dysplasia (TVD) are rare
forms of congenital heart disease that carry high rates of perinatal
mortality when diagnosed in utero.
• This population has been shown to have altered left ventricular (LV)
function and cerebral vascular resistance when compared with
gestational-age matched fetuses.
WHAT DOES THIS STUDY ADD?
• Measurements of LV function and cerebral vascular resistance were
compared between surviving and non-surviving fetuses with EA/
TVD, revealing novel insights into hemodynamic derangements
and their association with outcomes.
• Additionally, analysis of the components of the LV myocardial
performance index as physiological indicators of impaired LV filling,
revealed a novel and potentially valuable echocardiographic tool
worthy of further investigation.
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