In Utero Valvuloplasty for Pulmonary Atresia With Hypoplastic Right Ventricle: Techniques and Outcomes

Abstract

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.

Diagnosis and Treatment of Fetal Cardiac Disease

“…Fetal echocardiography demands detailed evaluation of cardiac anatomy and cardiac function with 2D imaging, M-mode imaging (for rhythm assessment), and Doppler interrogation that goes beyond the basic screening examination typically used in obstetric ultrasound. Guidelines for training for physicians who evaluate [158][159][160] Progressive atrioventricular or semilunar valve obstruction 155,161,162 Progressive atrioventricular valve, ventricular, great artery, branch pulmonary artery, and arch hypoplasia secondary to obstructive lesions or reduced blood flow 136,161,[163][164][165][166] Development of myocarditis or cardiomyopathy [167][168][169][170] Progressive myocardial dysfunction secondary to structural, functional, or rhythm disturbances that may lead to the evolution of hydrops or sudden fetal demise and interpret these specialized examinations exist; a detailed discussion is outside the scope of this document and may vary regionally. It is recommended that only well-trained or experienced pediatric cardiologists, maternal-fetal medicine specialists, obstetricians, or radiologists who have acquired the appropriate knowledge base and skills should supervise and perform fetal echocardiograms.…”

“…166 Defining the optimal candidates for prenatal opening of the pulmonary valve and developing effective techniques that are unique to the right side of the heart are continuing challenges. Fetal intervention may be considered in select cases; however, benefit is uncertain.…”

Fetal Echocardiography and Prenatal Cardiovascular Interventions – An Update (2012)

“…We now know that critical outflow tract obstruction in the absence of severe atrioventricular valve insufficiency in the mid trimester fetus is often associated with the evolution of a hypoplastic ventricle and great artery ipsilateral to the obstruction [83][84][85][86][87][88][89]. We have also learned that functional abnormalities involving only one ventricle may also be associated with abnormal growth and progressive hypoplasia of the affected ventricle and may contribute as an etiology to such conditions as hypoplastic left heart syndrome ( Figure 8) [90,91].…”

“…To date, several case reports and one series have been reported and reviewed [87,[97][98][99]136]. In a series of 10 affected fetuses, Tworetzky and colleagues reported technical success in 60% and growth of right heart structures in several.…”

Role of quantitative assessment in fetal echocardiography

“…These observations have prompted the development of fetal cardiac intervention to prevent the evolution of more severe secondary pathology, which has the potential to significantly improve the postnatal prognosis of affected fetuses 9,10 . Serial evaluation of fetal ventricular and great artery dimensions following intervention provides evidence for the impact of intrauterine intervention, with normalization of growth suggesting success 9,10 .…”