Introduction: The ductus arteriosus (DA) plays a major role in fetal circulation. Antenatal ductus closure is uncommon and can lead to pressure overload of the right ventricle (RV) and consecutive RV hypertrophy. We present 5 newborns with in utero restrictive DA.
Methods: Restrospective study of newborns with in utero restrictive DA. Charts and echocardiography were reviewed. 3 patients were identified as having a restrictive DA in utero and 2 others were identified because of post natal severe RV hypertrophy with low transcutaneous saturation and absent DA on echocardiography in the first hours after birth.
Results: Pre-natal diagnosis was made between 1 and 6 weeks before birth, all babies were born by ceasarian section because of severe RV hypertrophy and decreased RV function. Post-natal diagnosis was made at time of echocardiography between 1 and 10 hours of life. Clinically all patients had abnormally low transcutaneous saturation (84% [range: 80-88%]) not responding to supplemental O2. All patients developed respiratory distress needing non invasive or mechanical ventilation. Echocardiography demonstrated in all patients a severe RV hypertrophy (RV free wall 7.3 mm (5.8-8.5 mm), free wall of left ventricle (LV) 3.0 mm [2.5-3.6 mm]), 4 patients presented a small RV chamber with mean end diastolic RV volume of 9 ml/m2 (5-14 ml/m2) and one a dilated RV. All patients demonstrated RV diastolic dysfunction with consecutively bidirectional shunt at the foramen ovale level. In 3 patients there was high systolic RV pressure with increased tricuspid regurgitation. In those 3 patients, initial RV systolic function was decreased. DA was either absent or smallish. Treatment ranged from clinical observation to intensive treatment with O2, NO and sildenafil. Catecholamine infusion was given to sustain RV systolic and diastolic function in 3 patients. All patients survived with regression of RV hypertrophy and of RV dysfunction within months.
Conclusions: Premature closure of the DA can be diagnosed in utero and close monitoring of RV function is mandatory. Depending on the time between DA restriction and birth, post natal evolution could be complicated with need of RV afterload reduction and catecholamines, but once initial adaptation is overpassed RV hypertrophy regression occurs in all patients.