Keywords
fetal - noncompaction cardiomyopathy - coarctation of the aorta
Case Report
A 30-year-old primigravida was referred for evaluation and transfer of care due to
multiple fetal abnormalities at 29 weeks of gestation. At 22 + 2 weeks of gestation
she had a targeted ultrasound at an outside facility which revealed severe bilateral
hydronephrosis and hydroureters as well as thickened and dilated fetal ventricular
walls. A genetic amniocentesis was performed and the fetal karyotype was normal with
no 22q deletion.
The patient relocated and was evaluated with a targeted ultrasound and fetal echocardiogram
at our facility at 29 + 6 weeks of gestation. Ultrasound showed normal fetal growth,
severe bilateral hydronephrosis (20 mm) and hydroureters, and polyhydramnios with
an amniotic fluid index of 29.2. Detailed fetal cardiac evaluation revealed an enlarged
cardiac size, trabeculated left ventricular apex, moderately diminished systolic function,
and dilation of her ascending aorta with hypoplasia of the transverse aortic arch.
The fetal echocardiographic findings were consistent with left ventricular noncompaction
(LVNC) cardiomyopathy with associated coarctation of the aorta ([Fig. 1]).
Fig. 1 Fetal echocardiogram of the aortic arch at 29 + 6 weeks demonstrating postductal
coarctation of the aorta. “Posterior shelf” is labeled with white arrow.
The maternal echocardiogram did not show evidence of LVNC. The patient also had a
fetal magnetic resonance imaging, pediatric urology consultation, and neonatal intensive
care unit (NICU) consultation. She underwent a primary cesarean section at term to
facilitate coordination among the multiple pediatric subspecialists. The female infant
weighed 3,350 g with Apgar scores of 8 and 9 at 1 and 5 minutes, respectively.
The infant required intubation shortly after admission to the NICU and inotropic therapy
with dobutamine, epinephrine, and milrinone. Postnatal echocardiogram confirmed noncompaction
of the left ventricle and severely depressed contractility with an ejection fraction
(EF) of < 15% ([Fig. 2]). There was a critical postductal coarctation of the descending thoracic aorta and
a dilated aortic root (15 mm). On day of life (DOL) 1, the infant was taken to the
operating room for repair of her coarctation. The procedure was complicated by cardiac
arrest and therefore the coarctation repair was aborted. The following day the infant
had a cardiac catheterization and stent placement to relieve the coarctation of the
aorta. Despite correction of the coarctation, the infant's cardiac function did not
improve. She was listed for cardiac transplantation on DOL 5.
Fig. 2 Short axis postnatal echocardiogram image of the left ventricle demonstrating noncompaction
of the myocardium.
Cord blood revealed a normal array comparative genomic hybridization. Genetic testing
for cardiomyopathy, Marfan, and Barth syndrome was negative. The infant's cardiovascular
status then improved in response to medications. The neonate was extubated and weaned
from inotropic support. While her heart still demonstrates continued left ventricular
systolic dysfunction with an EF of 36%, she is clinically stable. She remains on aspirin,
losartan, spironolactone, and furosemide. She is off the transplant list and was discharged
home from the hospital at 15 weeks of age.
Discussion
Noncompaction cardiomyopathy is a rare form of cardiomyopathy that has seldom been
described prenatally. It is characterized by deep trabeculations in the muscle of
the left ventricle forming a “spongy” myocardium. This results in two layers of myocardium,
an outer compacted layer and an inner noncompacted layer ([Fig. 3]). The spongiform layer can lead to epicardial and myocardial dysfunction resulting
in poor contractility and poor filling. LVNC is a congenital abnormality that is suspected
to occur due to a morphogenetic abnormality involving an arrest of compaction of the
loose myocardial meshwork during fetal ontogenesis.[1] This occurs between the 5th and 8th weeks of gestation. LVNC is almost invariably
associated with other congenital cardiac malformations[2] including atrioventricular canal defects, double-outlet right ventricle, valvular
atresias, ventricular septal defect, and transposition of the great arteries.[3]
Fig. 3 Short axis fetal echocardiographic image showing the left ventricle (L) with two
distinct layers of myocardium; a thin compacted layer and a “noncompacted layer” with
deep trabeculations and crevices.
We present a case of the prenatal diagnosis of postductal coarctation of the aorta
and LVNC, a rare combination. The ability to recognize LVNC in the fetus is difficult;
therefore, it has rarely been described in this population.[3] In addition, detection of coarctation of the aorta is also challenging prenatally.
Coarctation of the aorta can be a progressive lesion in utero with relative worsening
of the distal arch hypoplasia in later gestation, due to continual decrease in the
amount of blood flow traversing the isthmus as pregnancy progresses.[4] Quantitative distal aortic arch hypoplasia and ventricular and great artery size
discrepancy have been observed and may facilitate the diagnosis of coarctation of
the aorta during serial echocardiographic evaluation.[5] Although distinct criteria have been established for the diagnosis of LVNC after
birth, criteria for diagnosis in the fetus have not been established.[3] Fetuses with structural cardiac defects and LVNC have a poorer prognosis than isolated
LVNC. In a case series by Arunamata et al, the neonatal mortality rate including progression
to heart transplantation among the fetuses with coexisting heart defects was 81%.[3] There are currently no published data on the long-term outcome of fetuses diagnosed
with noncompaction and depressed ventricular function.[6] The fetal presentation of LVNC can vary greatly from the hydropic fetus with dilated,
dysfunctional, and thick-walled ventricles to the patient with complex congenital
heart disease or less dramatic ventricular involvement.[7]
Treatment of LVNC depends on the presence or absence of other cardiac defects and
the clinical manifestations of heart failure, arrhythmias, and systemic embolic events.[6] Expression of disease in the fetus may be more severe than presentation later in
life[3] particularly if LVNC is coupled with other cardiac abnormalities. Heart transplantation
is a last resort for these patients. However, there may be a role for fetal listing
for neonatal heart transplantation in these rare cases of LVNC with significant ventricular
dysfunction. In our case, renal anomalies were also diagnosed prenatally, which precluded
fetal listing for cardiac transplantation. She was listed for cardiac transplantation
on DOL 5 when relief of the coarctation and inotropic support did not appear to improve
the neonate's cardiac status. Listing fetuses as candidates for neonatal heart transplantation
requires careful attention to the severity of the cardiac abnormalities, certainty
of an undesirable outcome without transplantation, the probability of success of transplantation,[8] and consideration of extracardiac anomalies.
Technical improvements in ultrasound equipment and advances in operator training have
increased the detection of fetal cardiac defects,[6] allowing for a multidisciplinary team approach in planning for delivery and neonatal
stabilization. LVNC and coarctation of the aorta are cardiac birth defects that can
be recognized prenatally with a high index of suspicion, therefore, making the transition
to postnatal life more successful. To our knowledge, this is the first reported case
of prenatally diagnosed LVNC associated with coarctation of the aorta with survival
in infancy.
