1, 2 - Radiology department, Kasr Alainy teaching hospitals, Cairo University, Egypt.

3 - Fetal medicine unit, Cairo University, Egypt.

Case report

A 23-year old woman (G1P0) on regular insulin therapy for type 1 diabetes was referred to us at 36 weeks of gestation due to suspected tricuspid regurgitation.

Ultrasound examination revealed the following findings:

• Dilated right atrium with congested IVC and hepatic veins denoting elevated right atrial pressure.

• Thickened hypertrophied free walls of the right ventricle with normal RV cavity.

• Severe tricuspid regurgitation. 

• Thickened dysplastic pulmonary valve leaflets showing restricted mobility with evident turbulent flow across a small stenotic valve area with estimated peak velocity across more than 2m/sec. (The velocity scale was elevated till reaching the nyquist limit and still there was aliased flow pattern across the valvular and supra valvular areas)

• Normal size and shape of main pulmonary artery and its major central branches as well as the tortuous arterial duct (no premature ductal constriction). Normal forward flow inside the arterial duct was seen with evident systolic retrograde flow into the main pulmonary artery.

• Normal right to left flow across foramen ovale.  

• Normal morphological appearance of the aortic arch in long axis view.

• Normal connection and drainage of inferior pulmonary veins into left atrium.

Our final diagnosis based upon morphologic and hemodynamic findings was severe valvular pulmonary stenosis with partial duct dependent pulmonary circulation.
Normal size of the RV cavity with free wall hypertrophy and reduced compliance (stiff myocardium compared to LV myocardium) denoted late onset of this valvular stenosis (after 20 weeks gestation) that exerted significant pressure overload on the RV without consequent chamber hypoplasia resulting in severe tricuspid regurgitation with restricted mobility of tricuspid valve leaflets. However, preserved systolic ejection capacity of the RV allowed considerable forward flow through the pulmonary valve with great flow turbulence across. Normal size and shape of main pulmonary artery as well as its major central branches with only systolic retrograde flow through the tortuous arterial duct into main pulmonary artery could virtually exclude the critical form of valvular pulmonary stenosis that usually shows minimal forward flow in MPA with complete duct dependent pulmonary circulation that requires postnatal ductal stenting or Modified Blalock-Taussig shunt to maintain pulmonary circulation.

There was no evidence of total anomalous pulmonary venous connection, coarctation of the aorta, restricted foramen ovale or premature constriction of ductus arteriosus.

A male baby (3200 g) was born without cyanotic features and was referred to Aswan Heart Center in which catheter assisted balloon valvuloplasty was done.

Images 1, 2, 3  and video 1: show congested IVC and hepatic veins, dilated right atrium and normal connection of pulmonary veins into LA.