The field of fetal surgery has made significant strides, particularly in cardiac interventions, which are now crucial for managing complex congenital heart diseases in utero. These advancements have provided opportunities to correct or palliate life-threatening anomalies before birth. Fetal cardiac interventions (FCI) are a key development in this area, offering innovative approaches to improve outcomes for affected fetuses.
FCI includes a range of ultrasound-guided, catheter-based procedures performed to treat severe cardiac anomalies. These interventions aim to modify disease progression, enhance postnatal outcomes and increase survival rates. Primary conditions addressed by FCI include fetal aortic stenosis with evolving hypoplastic left heart syndrome (HLHS), HLHS with intact or restrictive atrial septum and pulmonary atresia with intact ventricular septum (Sampat and Losty, 2021).
Fetal aortic stenosis is a critical condition that can progress to HLHS if untreated. HLHS is characterized by an underdeveloped left heart, incapable of supporting systemic circulation. The progression involves increased left ventricular pressure, leading to myocardial fibrosis and growth arrest of left heart structures. Fetal aortic valvuloplasty is designed to alleviate this pressure, promote left heart growth and prevent HLHS. This technique involves percutaneous introduction of a balloon catheter into the fetal heart to dilate the stenotic aortic valve, performed under maternal conscious sedation and fetal anesthesia. Studies have shown high rates of technical success and significant improvements in fetal hemodynamics, leading to better postnatal outcomes for infants undergoing this procedure (Sampat and Losty, 2021).
HLHS with an intact or restrictive atrial septum poses another critical challenge, as it leads to severe neonatal hypoxia and pulmonary venous hypertension. The rationale for FCI in these cases is to create or enlarge the atrial septal defect, improving oxygenation and reducing pulmonary hypertension. Techniques such as fetal atrial septoplasty or stent placement are employed to achieve these goals. Although these procedures are technically demanding, they have demonstrated potential in reducing neonatal morbidity and mortality associated with HLHS (Sampat and Losty, 2021).
In cases of pulmonary atresia with intact ventricular septum, FCI aims to prevent right ventricular hypoplasia and promote right heart growth. The procedure typically involves balloon valvuloplasty or stenting to ensure adequate blood flow through the pulmonary valve. Early intervention is crucial to prevent the progression of right ventricular dysfunction and improve postnatal cardiac function (Sampat and Losty, 2021).
The field of cardiac fetal surgery continues to evolve with ongoing innovations in imaging, instrumentation and surgical techniques. The development of high-resolution fetal echocardiography and MRI has significantly enhanced the diagnosis and assessment of congenital heart diseases, enabling precise planning and execution of FCI. Additionally, advancements in catheter technology and fetal anesthesia have improved the safety and efficacy of these procedures. Cardiac fetal surgery represents a transformative approach to managing severe congenital heart diseases. Through continued innovation and collaboration, there is immense potential to improve the quality of life and survival rates for affected infants, heralding a new era in fetal medicine and pediatric cardiology.
