Tetralogy of Fallot with pulmonary atresia – Role of patent ductus arteriosus stenting as initial palliation

Traditionally, the modified Blalock-Taussig-Thomas shunt (mBTTS) has been the standard palliation for duct-dependent pulmonary blood flow (DDPBF) lesions, including tetralogy of Fallot with pulmonary atresia (TOF-PA). However, the risks associated with mBTTS, especially in neonates with low birth weight and small pulmonary arteries, have led to the exploration of less invasive alternatives like ductal stenting (DS). This review compares the anatomy and physiology of TOF with pulmonary stenosis and TOF-PA, noting that TOF-PA often relies on the patent ductus arteriosus (PDA) for pulmonary blood flow. It details the complexities of PDA morphology in DDPBF lesions, which can present as simple or complex structures. Historically, early experiences with DS revealed high complication rates, resulting in cautious recommendations against its use in certain anatomical contexts. However, improvements in stent technology and understanding of the complex congenital cardiac anatomy have improved the feasibility of DS as a viable option when the PDA is the sole source of pulmonary blood flow. We also explore issues like the less durable palliation compared to mBTTS, technically challenging stent placement, rapid neointimal proliferation causing in-stent stenosis and compromising pulmonary artery (PA) perfusion, and asymmetrical PA branch growth in the presence of stent jailing of a branch PA. In conclusion, this review suggests that while DS is increasingly seen as a reasonable alternative to mBTTS, it requires careful patient selection and close monitoring, alongside ongoing research to refine techniques and improve long-term outcomes for TOF-PA patients.