Case Report
Venous-Arterial ECMO as a Vital Bridge for Survival in a Neonate with Cor-triatriatum Dexter
Bianca Lo Verde1, Sunjay Kaushal2, Michael C Slack3 and Sripriya Sundararajan*1
1Department of Pediatrics, University of Maryland Medical Center, USA
2Department of Cardio-Thoracic Surgery, University of Maryland, USA
3Department of Pediatric Cardiology, University of Maryland, USA
*Corresponding author: Sripriya Sundararajan, Department of Pediatrics, University of Maryland School of Medicine, 110 S Paca Street, Paca-Pratt building, Rm 8-S-164, Baltimore, MD 21201, USA
Published: 08 Aug, 2017
Cite this article as: Verde BL, Kaushal S, Slack MC,
Sundararajan S. Venous-Arterial
ECMO as a Vital Bridge for Survival in
a Neonate with Cor-triatriatum Dexter.
Ann Clin Case Rep. 2017; 2: 1409.
Abstract
Cor-triatriatum dexter is an extremely rare congenital heart disease which can present with varied clinical manifestations. These range from being asymptomatic, incidentally diagnosed during cardiac surgery, right-sided heart failure, cyanosis and death in the neonatal period. This heart defect results from remnants of the right valve of the sinus venosus causing varying degrees of obstruction to the tricuspid valve in flow. We present a neonate with cor-triatriatum dexter who initially failed a car seat tolerance screening test and rapidly deteriorated into cardiogenic shock with tricuspid valve inflow occlusion after closure of Patent Ductus Arteriosus (PDA). The PDA was completely unresponsive to prostaglandins, necessitating emergent institution of venous-arterial extra corporeal membrane oxygenation (VA-ECMO), which provided a vital bridge for survival followed by early primary surgical resection of the cor-triatriatum dexter membrane. Without VAECMO, an adverse outcome may have ensued from a surgically correctable congenital heart defect. In this report, we stress both the need for a high index of suspicion of this rare anomaly and the value of VA-ECMO as a bridge to successful surgical correction in a symptomatic neonate with a cardiac defect that offers excellent prognosis post-surgical correction.
Keywords: Cor-triatriatum dexter; VA-ECMO; Neonate
Introduction
Cor-triatriatum dexter is an extremely rare congenital heart defect with prevalence of less than 0.01% [1]. This results from the complete persistence of the right valve of the embryonic sinus venosus, also known as the Eustachian valve, as a membrane or fibro muscular band [2]. This results in the division of the right atrial chamber into two compartments. The membrane protrudes into the right ventricular chamber through the tricuspid valve, causing choking of the right ventricular inlet and altered hemodynamics. This allows obligatory right to left shunting at the atrial septal level resulting in profound cyanosis. Herein we report a case of newborn that failed a car seat tolerance (CST) screening test that was successfully treated by primary cardiac surgical repair after a brief course of Venous-Arterial Extra Corporeal Membrane Oxygenator (VA-ECMO) at University of Maryland Medical Center (UMMC).Uniquely, this is the first reported case emphasizing the importance of VA-ECMO to serve as a vital bridge for survival in a neonate.
Case Presentation
A female infant was born at 36 6/7 weeks of gestation via spontaneous vaginal delivery to a 20 year old mother at an outside hospital. There was normal prenatal care and no underlying family
history of congenital heart disease. All routine maternal prenatal screening labs were negative.
Apgar scores of the newborn at 1 and 5 minutes were 8 and 9, with birth weight of 2665 g. The baby
was transferred to the newborn nursery soon after birth and was bottle fed formula with volumes
ranging 15-30 ml for approximately 24 hrs. As part of routine discharge planning of any infant born
prior to 37 weeks gestation, a CST screening test was performed close to 41 hrs of life. Once placed
in the car seat, the baby began having episodes of oxygen de-saturations (65%-88%) while breathing
room air. Failing the test, the infant was quickly transferred to the radiant warmer for respiratory
support. Due to continued de-saturations, the baby was placed on 100% oxygen delivered through
a 2 L high flow nasal cannula with minimal change in oxygen saturations. She was immediately
transferred to the newborn intensive care unit (NICU) at UMMC to rule out cyanotic congenital
heart disease.
Following admission to the NICU, the newborn was found to
have central cyanosis with oxygen saturations between 60%-75%
despite remaining on 100% oxygen through 4L of high flow nasal
cannula. The physical exam was otherwise remarkable for a baby with
vigorous cry with no signs of respiratory distress. Cardiovascular
examination revealed a quiet precordium with normal heart sounds
and no audible cardiac murmur. Chest x-ray showed pulmonary
oligemia with normal lung volumes and normal sized heart. Arterial
blood gas confirmed severe hypoxemia with partial pressure of
oxygen at 35mmHg on 100% oxygen.
The baby was electively intubated in the NICU and placed on
the high frequency oscillator in an attempt to improve oxygenation.
Simultaneously, pediatric cardiology was consulted for persistent
neonatal cyanosis. Initial echocardiogram demonstrated a redundant
“cor” membrane in the right atrial chamber just above the tricuspid
valve inlet in atrial diastole (Figure 1A) flopping into the orifice of
the tricuspid valve during atrial systole (Figure 1B). A small hole in
the membrane was visible through which some forward blood flow
passed into the pulmonary arteries. A hypertrophied small cavity right
ventricle, right to left shunt across the large atrial septal defect, and right
to left bowing of the atrial septum were also present. Also, remarkably,
a patent ductus arteriosus (PDA) could not be visualized. The baby was
immediately started on a continuous prostaglandin (PGE1) infusion
in addition to a dopamine infusion and hydrocortisone in an effort
to improve systemic oxygenation. However, the infant continued
to deteriorate progressively to respiratory failure from cardiogenic
shock secondary to tricuspid inflow blockage and worsening right to
left inter-atrial shunting. In an effort to open the PDA, an intravenous
bolus of PGE1 (180 micrograms) was attempted with no response.
Bedside echocardiogram performed serially for several minutes after
the PGE1 infusion and bolus demonstrated no ductal flow on color
Doppler. At this point, the baby was critically ill with oxygenation
index exceeding 40 and the ECMO team was activated. VA-ECMO
cannulation was performed at the bedside at a point approximately 3
hours after her arrival to the NICU. Arterial blood gases immediately
improved and baby was transferred to the cardiac section of the
pediatric intensive care unit (PICU) for further cardiac management.
Repeat echocardiogram after institution of VA-ECMO
interestingly showed that the right jugular venous cannula had
deflected the cor-triatriatum dexter membrane away from the
tricuspid valve inlet and pinned it against the Inferior Vena Cava-
Right Atrial junction (Figure 2). ECMO flows were however adequate
and the infant stabilized thereafter. There was some concern regarding adequate size of the right ventricle. However, the tricuspid valve annulus diameter z-score was reassuring at -2.0. The following
morning, the baby was taken to the operating room. Intra-operative
findings were consistent with the diagnosis of cor-triatriatum
dexter. The right atrial membrane that was resected was found to
be pedunculated and attached to the crista terminalis, eustachian
valve, and tricuspid valve annulus. The atrial septal defect was closed
primarily. Her post-operative course was fairly uncomplicated. She
had a small residual atrial level communication, and was diagnosed
with unilateral partial paralysis of the vocal cord that spontaneously
resolved. She was evaluated by a pediatric geneticist and was found
to have a normal single nucleotide polymorphism array. The baby
was discharged on hospital day 13 on low dose aspirin. She continues
to gain weight, is currently thriving well and has regular follow up
appointments with pediatric cardiology.
Figure 1
Figure 1
(A) Parasternal short axis echocardiographic image clip taken in atrial diastole demonstrating the mobile “cor” membrane just above the tricuspid valve
inlet (hollow arrow).
(B) Clip taken during atrial systole demonstrating the cor membrane flopping dynamically into the inflow path of the tricuspid valve causing obstruction (asterisk).
Additionally, a large atrial septal defect is visible (solid white arrow). RV: Right Ventricle; RA: Right Atrium; AO: Aorta; LA: Left Atrium
Figure 2
Figure 2
Echocardiographic image clip taken in parasternal short axis
view after emergent institution of Venous-Arterial ECMO from the right neck
showing how the venous cannula had pinned the “cor” membrane away from
the tricuspid valve inlet thereby allowing temporary unobstructed opening of
the tricuspid inlet (solid arrow).
RV: Right Ventricle; RA: Right Atrium; AO: Aorta; PV: Pulmonary Vein
Discussion
This is the first reported case emphasizing the importance of
VA-ECMO in a neonate to serve as a vital bridge for survival prior
to successful treatment by primary cardiac surgical repair for cor
triatriatum dexter. Initiation of VA-ECMO was of vital importance in
this case due to the due to the rapid development of cardiogenic shock
from presumed early PDA closure. Although only a few reports of
cor-triatriatum dexter that lead to cyanosis with an otherwise normal
exam in a new born exist in the literature [3,4] our case is unique in that closure of the PDA was refractory to PGE1 and precipitated rapid deterioration into cardiogenic shock with profound hypoxemia
and respiratory failure.
When diagnosing cor-triatriatum dexter, the physical exam
is rarely helpful, as a murmur may not be audible due to lack of
turbulent blood flow across the membrane. The chest X-ray usually
demonstrates a normal cardiac silhouette and normal lung volumes.
Intermittent episodes of central cyanosis and de-saturations can be
missed in the immediate newborn period. Clinical presentation can
range from being asymptomatic in the newborn period to reports of
pulmonary hypertension and cardiac failure at an older age [2,5-8].
Thorough echocardiographic imaging is therefore mandatory. Both
short term and long term prognosis is usually excellent following
surgical repair [9]. The use of ECMO as a life-saving measure for
a cyanotic neonate with isolated cor-triatriatum dexter has been
reported in older children [10], but none have been previously
reported in a neonate. While limited case series on symptomatic
neonatal presentations can be found, none of the neonates discussed
progressed to such extremis as the case reported herein. A 4 month
old infant with cor-triatriatum dexter required ECMO secondary to
pulmonary hypertension, but had associated structural heart defects
including pulmonary vein stenosis, large ventricular septal defect and
atrial septal defect. In that case, the infant was decannulated, but died
prior to surgical repair [11].
Additionally, herein, we present a case of a newborn with cortriatriatum
dexter who failed a car seat test. CST screening test is a
common pre-discharge assessment requisite for newborns born <37
weeks gestational age or <2500 g. The utility of the test remains in
identifying infants at risk for adverse cardiopulmonary outcomes after
discharge from the newborn nursery [12,13]. In this neonate, the CST
screening test, offered the opportunity to screen an otherwise healthyappearing
baby for this potentially lethal congenital heart defect. If
this screening had not been performed, an adverse outcome may have
ensued. This raises very important questions about the babies who are
deemed eligible for the CST screening test. It also raises the spectre
of the importance that all newborn nurseries, even low risk newborn
units, adopt routine neonatal pulse oximetry screening that may serve
as an important backup [14].
Conclusion
High index of suspicion is necessary to diagnose rare conditions such as cor-triatriatum dexter in an otherwise normal appearing neonate with repeated desaturations and cyanosis in the immediate newborn period. Our case report provides emphasis of the importance of VA-ECMO as a vital bridge to survival in a neonate until primary cardiac repair despite failed attempts to pharmacologically open the closed PDA.
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