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In utero valvuloplasty for pulmonary atresia with hypoplastic right ventricle: techniques and outcomes
Wayne Tworetzky1, Doff B McElhinney, Gerald R Marx
1Department of Cardiology, Children's Hospital, Boston, MA 02115, USA. wayne.tworetzky@cardio.chboston.org
Insights
Prenatal intervention for pulmonary atresia with an intact ventricular septum (PA/IVS) may improve fetal heart growth. Successful in utero procedures show enhanced right heart development in fetuses with moderate hypoplasia.
Area of Science:
- Cardiology
- Fetal Medicine
- Pediatric Surgery
Background:
- Pulmonary atresia with an intact ventricular septum (PA/IVS) presents challenges for right heart development.
- Prenatal intervention aims to improve fetal right heart physiology and promote biventricular outcomes.
Purpose of the Study:
- To evaluate the feasibility and impact of in utero pulmonary valve (PV) balloon dilation for fetuses with PA/IVS.
- To assess the effect of prenatal intervention on right heart growth in affected fetuses.
Main Methods:
- Intervention considered for fetuses with membranous PA/IVS, intact septum, and right heart hypoplasia (tricuspid annulus z-score ≤ -2).
- Procedures performed via ultrasound-guided cardiac puncture, with percutaneous or limited laparotomy access.
- Ten fetuses with PA/IVS underwent attempted in utero PV balloon dilation.
Main Results:
- Six of ten attempted procedures were technically successful.
- Successful interventions were associated with significantly greater growth of the tricuspid valve annulus, right ventricle, and PV annulus compared to controls.
- Fetuses undergoing successful prenatal intervention showed improved right heart growth from midgestation to late gestation.
Conclusions:
- In utero PV perforation and dilation is technically feasible for midgestation fetuses with PA/IVS.
- The procedure may improve right heart growth and postnatal outcomes in fetuses with moderate midgestation right heart hypoplasia.
- A significant learning curve exists, and careful patient selection is crucial for optimal outcomes.
Background:
Prenatal intervention for fetuses with pulmonary atresia with an intact ventricular septum (PA/IVS) has the potential to alter right heart physiologic features in utero, facilitating right heart growth and improving the prospect of a biventricular outcome after birth.
Methods:
Since 2002, we have considered prenatal intervention for fetal PA/IVS in patients with (1) membranous pulmonary atresia, with identifiable pulmonary valve (PV) leaflets or membrane; (2) an intact or highly restrictive ventricular septum; and (3) right heart hypoplasia, with a tricuspid valve annulus z score of -2 or below and an identifiable but small right ventricle. Intervention was performed through direct cardiac puncture under ultrasound guidance, with percutaneous access or access through a limited laparotomy.
Results:
Ten fetuses underwent attempted balloon dilation of the PV in utero. The first 4 procedures were technically unsuccessful, and the most-recent 6 were technically successful. Compared with control fetuses with PA/IVS who did not undergo prenatal intervention and had univentricular outcomes after birth, the tricuspid valve annulus, right ventricle length, and PV annulus grew significantly more from midgestation to late gestation in the 6 fetuses who underwent successful interventions.
Conclusions:
In utero perforation and dilation of the PV in midgestation fetuses with PA/IVS is technically feasible and may be associated with improved right heart growth and postnatal outcomes for fetuses with moderate right heart hypoplasia in midgestation. There is an important learning curve for this procedure, and much remains to be learned about the selection of appropriate fetuses for prenatal intervention.
