Fetal pulmonary valvuloplasty in fetuses with right ventricular outflow tract obstructive disease: experience and outcome of the first five cases in China

Background To report our initial experience of fetal pulmonary valvuloplasty (FPV) in fetuses with pulmonary atresia with intact ventricular septum (PA/IVS) or critical pulmonary stenosis (CPS), including the experiences of case selection, technical feasibility, post-FPV effects in utero and the postnatal outcome. Methods Two cases with fetal PA/IVS and three cases with fetal CPS were enrolled between September 2016 and April 2018, and all cases were diagnosed with severe right ventricular dysplasia and growth arrest by fetal echocardiogram. Parameters of right heart structure development and hemodynamics from echocardiography included tricuspid /mitral annulus ratio (TV/MV), right ventricle/left ventricle long-axis ratio (RV/LV), tricuspid valve inflow duration/cardiac cycle ratio (TVI/CC), degree of tricuspid regurgitation (TR), blood flow direction of arterial duct and ductus venosus. FPV procedure was performed trans-abdominally under ultrasound-guidance. Echocardiography was performed post-procedure immediately and every 2-4 weeks until delivery. Results Seven FPV have been performed in the five fetuses with PA/IVS or CPS. The median gestational age at the time of FPV was 28 weeks. From technical perspective, pulmonary balloon valvuloplasty was successfully performed in all cases. The opening of pulmonary valve improved in these five cases in 2-4 weeks. However, progressive restenosis was detected in four fetuses during advancing gestation and re-atresia occurred in two PA/IVS cases at 36 weeks and 37 weeks gestation, respectively. The growth trajectories of TV/MV, RV/LV, and TVI/CC improved in the first weeks, and then slowed down along with the pulmonary valve restenosis. All fetuses were born alive and underwent postnatal interventions, including pulmonary balloon valvuloplasty in 3 cases and surgical procedures in 2 cases. During the follow-up, three fetuses became biventricular, one case became one and a half ventricular at one year of age and the other one died of neonatal infection. Conclusion FPV is feasible and safe for fetuses during the second and third trimester of pregnancy. PV restenosis may occur as pregnancy advances, but overall, FPV still improved the growth trajectories of fetal right heart structures and has the potential to alter the natural history of PA/IVS and CPS.