Ebstein’s anomaly with coarctation of the aorta and a bicuspid aortic valve: a case report of a rare association with unique prenatal findings

Abstract

Ebstein’s anomaly is rarely accompanied by coarctation of the aorta, although patients with Ebstein’s anomaly have a relatively small left ventricle. Here, we report a rare case of Ebstein’s anomaly with coarctation of the aorta and a bicuspid aortic valve. We compared the foetal echocardiographic parameters of five previous cases with Ebstein’s anomaly without left heart obstruction to explore the association between left ventricular volume, Ebstein’s anomaly severity, and left heart obstruction.

Introduction

Ebstein’s anomaly comprises<1% of CHDs cases ¹ and is characterised as apical displacement of the tricuspid valve with a varying degree of tricuspid regurgitation. As a result, left ventricular volume is often smaller than right ventricular volume in patients with Ebstein’s anomaly. ¹

Similarly, coarctation of the aorta is associated with a small left ventricle. ² However, an association between coarctation of the aorta and Ebstein’s anomaly is extremely rare. ³

Here, we present a rare case of Ebstein’s anomaly with coarctation of the aorta and a bicuspid aortic valve. In this report, the association between left ventricular volume, severity of Ebstein’s anomaly, and left heart obstruction was evaluated by comparing the foetal echocardiographic parameters of Ebstein’s anomaly cases with and without left heart obstruction.

Case presentation

A 33-year-old woman (gravida 5, para 2) was referred to our hospital due to foetal growth retardation at 29 weeks of gestation. At gestational week 30, Ebstein’s anomaly was observed on foetal echocardiography. Apical displacement of the septal and anterior tricuspid leaflets was shown, with a Celermajer score of 0.73; however, tricuspid valve regurgitation was mild. Normal antegrade flow from the RV to the pulmonary artery at the velocity of 65cm/s and normal antegrade flow in the ductus arteriosus was seen. The left side of the heart was considered hypoplastic (mitral valve diameter Z-score, −2.25; left ventricular width Z-score, −3.78; left ventricular length Z-score, −2.10; aortic valve diameter Z-score, −2.60), whereas the aortic isthmus diameter was not hypoplastic (3.2 mm; Z-score, −0.83; Fig 1a). At gestational week 36, aortic isthmus narrowing (diameter, 2.6 mm; Z-score, −3.74) and diastolic reverse flow in the aortic arch was identified. Coarctation of the aorta was suspected (Figure 1b) (Videos; Supplementary Figure S1, S2).

Figure 1. Fetal echocardiography and post-natal three-dimensional contrast-enhanced CT images. (a) A four-chamber view in foetal echocardiography at 30 weeks of gestation, (b) a sagittal view of the aortic arch at 36 weeks of gestation (arrow indicating CoA), and (c) a three-dimensional contrast-enhanced CT reconstructed image showing CoA (software: Ziostation2 Plus, Ziosoft, Inc. Tokyo, Japan). CoA = coarctation of the aorta.

At birth (38 weeks and 4 days of gestation), the female neonate weighed 2082 g, with an oxygen saturation level of 97%. The Apgar scores were 8 and 9 at 1 min and 5 min, respectively, and no tachypnoea was noted. Post-natal transthoracic echocardiography confirmed the presence of Ebstein’s anomaly with mild tricuspid valve regurgitation. The aortic valve was bicuspid but not stenotic. Additionally, the left ventricle was mildly hypoplastic with an end-diastolic diameter of 12.6 mm (Z-score, −2.82). Coarctation of the aorta was suspected because the aortic isthmus measured only 2 mm (Z-score, −4.7). The patient was monitored accordingly. At 1 day old, a 30-mmHg pressure difference between the upper and lower extremities was observed, along with closure of the ductus arteriosus. Contrast-enhanced CT (three-dimensional reconstruction in Fig 1c) confirmed a diagnosis of coarctation of the aorta. Treatment with prostaglandin E₁ was initiated, and aortic arch reconstruction was performed on post-natal day 2. Postoperative echocardiography revealed an unchanged degree of tricuspid regurgitation but an improved left ventricular end-diastolic diameter of 17.5 mm (Z-score, 0.67). The patient was discharged without complications.

The foetal echocardiographic parameters of six patients who had been prenatally diagnosed with Ebstein’s anomaly at our institution between 2013 and 2021 are shown in Table 1. The left ventricular diameter Z-score was extremely small in the present case when compared with previous Ebstein’s anomaly cases without a bicuspid aortic valve or coarctation of the aorta. Additionally, the right-to-left ventricular diameter ratio was considerably greater in the present case than in previous cases.

Table 1. Foetal echocardiographic parameters of five cases of Ebstein´s anomaly without coarctation of the aorta and the present case

CoA = coarctation of the aorta; CTAR = cardiothoracic area ratio; GA = gestational age; LV = left ventricle; RV = right ventricle; TR = tricuspid valve regurgitation; NA = not available.

Discussion

Here, we present an extremely rare case of Ebstein’s anomaly with a bicuspid aortic valve and coarctation of the aorta. The patient had a markedly smaller left ventricle when compared with previous cases of Ebstein’s anomaly observed at our institution without left heart obstruction.

Some cases of Ebstein’s anomaly with coarctation of the aorta and congenitally corrected transposition of the great arteries have been reported; ⁴ however, Ebstein’s anomaly with coarctation of the aorta in atrioventricular- and ventriculoarterial-concordant hearts is extremely rare. Attenhofer Jost et al. reported that of 106 patients with Ebstein’s anomaly, eight (8%) had a bicuspid aortic valve and none had coarctation of the aorta. ³ To our knowledge, only five cases of Ebstein’s anomaly with coarctation of the aorta in atrioventricular- and ventriculoarterial-concordant hearts have been reported, including the present case. ^6–8

Previous studies have reported that greater right-to-left ventricular ratios were associated with worse haemodynamics and/or prognoses in foetuses with Ebstein’s anomaly. ^1,9 Liu et al. compared foetal echocardiographic parameters between healthy foetuses, foetuses with tricuspid malformations including tricuspid valve dysplasia or Ebstein’s anomaly and normal pulmonary flow, and f0etuses with tricuspid malformations and reduced or absent pulmonary flow. ¹ In the third trimester, the right-to-left ventricular ratios were 1.03 (1.00–1.07), 1.10 (1.05–1.50), and 1.31 (1.20–1.60), respectively. This result indicates that cases with tricuspid malformations had greater right-to-left ventricular ratios than healthy foetuses. The Z-scores for the left ventricular end-diastolic diameter were 0.06 ± 0.54, 0.12 ± 0.56, and 0.20 ± 0.97, respectively, and no significant difference in this score was identified between healthy foetuses and foetuses with tricuspid malformations and abnormal pulmonary flow. These results indicated that the left ventricle was relatively small compared with the right ventricle in patients with Ebstein’s anomaly, but the absolute size did not significantly differ from the normal range.

In contrast, the right-to-left ventricular ratio is known to be a predictive foetal echocardiographic parameter for the diagnosis of coarctation of the aorta. ² The present case demonstrated a considerably greater right-to-left ventricular ratio and smaller left ventricular diameter (based on the Z-score) than other cases of Ebstein’s anomaly without coarctation of the aorta. In foetal Ebstein’s anomaly with a markedly small left ventricle, concurrent coarctation of the aorta may need to be ruled out.

In patients with Ebstein’s anomaly or severe tricuspid malformations, the left ventricle plays a crucial role in supporting pulmonary circulation. However, in the present case, foetal heart failure was not observed despite the small left ventricle and a Celermajer score of grade 2, which typically do not indicate a favourable prognosis. ¹⁰ The mild tricuspid regurgitation observed in the present case may have made it possible to sufficiently maintain foetal circulation despite the suboptimal Celermajer score and small left ventricle.