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Prenatal diagnosis of absent pulmonary valve syndrome
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  1. Maria Lúcia Moleiro1 and
  2. Luís Guedes-Martins1,2
  1. 1Department of Women and Reproductive Medicine, Centro Hospitalar do Porto, Porto, Portugal
  2. 2Department of Experimental Biology, University of Porto, Porto, Portugal
  1. Correspondence to Dr Maria Lúcia Moleiro; lucia.moleiro{at}gmail.com

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Description

An 18-year-old woman, with a congenital subaortic interventricular communication, was diagnosed with a 17-week gestation. On the first echography, at that gestational age, a subaortic ventricular septal defect (VSD) with an over-riding aorta (Ao) was identified (figure 1) associated with bilateral feet polydactyly. A foetal echocardiography, a couple weeks later, confirmed the defects previously mentioned and detected a pulmonary valve (PV) agenesis with a stenotic pulmonary ring, pulmonary free insufficiency and right ventricular (RV) predominance. These features were compatible with absent pulmonary valve syndrome (APVS) with Fallot’s Tetralogy characteristics (TOF-type APVS), a rare cardiac outflow tract abnormality.1–3

Figure 1

Transverse five-chamber view showing the ventricular septal defect (VSD) with the over-riding aorta (Ao) and a massively dilated right pulmonary artery (RPA) seen in this plane. LV, left ventricle; RV, right ventricle.

APVS may be associated with chromosomal anomalies, and this relationship is more frequent with the TOF-type APVS.4 In the case described, amniocentesis was performed but no chromosomal or genetic variations, namely chromosome 22 microdeletion (22q11.2), were found. Nevertheless, given the poor prognosis, the patient requested pregnancy termination at 23 weeks gestation. The anatomopathological examination was concordant with the ultrasound findings.

Despite increasing knowledge, prenatal diagnosis of APVS remains a challenge and a major step in parents counselling given its serious postnatal complications.5 6 Globally, it is estimated that, absent PV syndrome affects 0.2%–0.4% of the newborns with congenital heart disease.6 Moreover, a higher frequency of congenital heart defects is known to occur in the offspring of parents who also have a congenital heart disease, namely atrioventricular defects.7

Pulmonary artery (PA) dilation on prenatal ultrasound may be a normal variation. However, its identification may also be present in isolated PV stenosis, ductus arteriosus constriction, situations of pulmonary hypertension or in TOF-type APVS.8 Differentiating features of TOF-type APVS include a massively dilated PA and its branches, left and right (5.8 mm, 6.4 mm and 4.2 mm, respectively, in this case) (figure 2A), a typical pattern of high velocities with colour aliasing between the right ventricle and the PA (figure 2B), a VSD, an overriding Ao and absence of ductus arteriosus.3 6

Figure 2

(A) Three-vessel view in grey scale. It is notorious the presence of severely dilated left (LPA) (6.4 mm) and right (RPA) (4.2 mm) pulmonary arteries. Typically, the ductus arteriosus is absent and the pulmonary valve (PV) is not seen. (B) Three-vessel view in colour Doppler showing the typical pattern of high velocities with colour aliasing. Ao, over-riding aorta; PA, pulmonary artery.

The heart structure can be explored by the first trimester echography but mother characteristics (such as obesity), foetal position or physiological adaptations of the foetal heart in-uterus may delay a definite diagnosis.5 Even an experienced sonographer may raise a suspicion of cardiac abnormalities only on the second or third trimester evaluation. Many times, the diagnosis happens just after birth.5

Learning points

  • Absent pulmonary valve syndrome (APVS) is a rare congenital heart disease, whose prenatal diagnosis is possible.

  • The APVS with Fallot’s Tetralogy characteristics includes a ventricular septal defect, a stenotic pulmonary ring with pulmonary insufficiency, and pulmonary arteries’ dilation.

  • Given association with other anomalies, and poor postnatal prognosis, early prenatal diagnosis of APVS is of major importance for parents prenatal counselling.

References

Footnotes

  • Contributors Both authors have actively contributed for the submitted work, meeting the required criteria for authorship. MLM did the research about the theme and previous case reports of the disease; wrote the article text and figure captions; prepared the article’s final version. LG-M provided the original case idea; acquired the images; revised the final article text.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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