Prenatal ultrasonic diagnosis of absent pulmonary valve syndrome: A case report

Abstract

Rationale: Absent pulmonary valve syndrome (APVS) is a rare congenital heart disease that is often associated with tetralogy of Fallot (TOF). Here, we report 2 cases of APVS associated with TOF diagnosed via fetal echocardiography and discuss their specific ultrasonographic characteristics.

Patient concerns: Two pregnant women with suspicion of fetal heart anomaly were referred from their local hospitals to our hospital for fetal malformation screening and detailed fetal echocardiography. Color and spectral Doppler flow imaging were utilized to evaluate the axis, size, situs, cardiac chambers, and both inflow and outflow tracts of the heart as well as the great arteries. Both cases had a severe dilatation of the pulmonary trunk and its branches and an absence or dysplasia of the pulmonary valve, which was associated with subaortic ventricular septal defect (VSD) with an overriding aorta. In addition, the fetus in case 1 showed a patent ductus arteriosus, and the fetus in case 2 showed arterial duct agenesis. Furthermore, color Doppler flow imaging showed a bi-directional multicolored flow signal in the pulmonary valve ring.

Diagnoses: Both fetuses were diagnosed with APVS associated with TOF.

Interventions: No therapeutic intervention was performed.

Outcomes: On the request of the pregnant women and their families, both fetuses were aborted.

Lessons: Although APVS is a rare congenital heart disease and often associated with TOF, it has an overall poor prognosis. Nowadays, it can be easily diagnosed via ultrasonography because of its typical ultrasonographic features, such as aneurysmal dilatation of pulmonary artery, massive regurgitation of the pulmonary valve, VSD, and an overriding aorta. Therefore, early fetal echocardiography screening should be performed for every fetus.

Figure 1

Ultrasonographic features of APVS for case 1. Under the 4-chamber view, the bilateral atrioventricular valves are normal; the VSD and the overriding aorta are clear (A). Under the RVOT view, the pulmonary artery ring size is narrowed to about 3.5 mm (B), and the MPA is dilated with a diameter of about 11.2 mm (C). On color Doppler flow image, multicolored mosaic flow signal is seen in the MPA (D). AO = aorta, APVS = absent pulmonary valve syndrome, LPA = left pulmonary artery, LV = left ventricle, MPA = mean pulmonary artery, PA = pulmonary artery, RPA = right pulmonary artery, RV = right ventricle, RVOT = right ventricular outflow tract, VSD = ventricular septal defect.

Figure 2

Ultrasonographic features of APVS for case 2. Under the 4-chamber view, the left and right atrioventricular valves are symmetrical (A). Under RVOT view, no obvious pulmonary valve activity is seen, the diameter of PA is about 8.2 mm, and the arterial duct is clearly shown (B). On color Doppler flow image, multicolored mosaic flow signal is seen in the MPA (C). On spectral Doppler flow image, antegrade and retrograde blood flow in the pulmonary trunk, and the right ventricle are shown (D). APVS = absent pulmonary valve syndrome, DA = arterial duct, DAO = descending aorta, LA = left atrium, LPA = left pulmonary artery, LV = left ventricle, MPA = mean pulmonary artery, PA = pulmonary artery, RA = right atrium, RPA = right pulmonary artery, RV = right ventricle, RVOT = right ventricular outflow tract, VSD = ventricular septal defect.

Figure 3

Aneurysmal dilatation of the main pulmonary artery without normal pulmonary valve tissue at pulmonary valve ring. AAO = ascending aorta, MPA = mean pulmonary artery, RVAW = right ventricular anterior wall.