Balloon valvoplasty in infants with tetralogy of Fallot: effects on oxygen saturation and growth of the pulmonary arteries

Palliative Balloon Pulmonary Valvotomy in Tetralogy of Fallot: Is There a Role in 2021?

The current treatment practice for Tetralogy of Fallot (TOF) is to undertake complete surgical repair between 6–9 months of age with excellent immediate and long-term results. In patients with increased cyanosis or frequent cyanotic spells, younger age of complete repair as early as 3 months is usually acceptable. Although neonatal TOF repair is reported with good immediate survival from a few centres, post-operative morbidity is significant, and the hospital stay is prolonged. Hence, in neonates and small term and preterm infants with severe cyanosis, palliative procedures such as modified Blalock-Taussig (BT) shunt, ductal stenting, right ventricular outflow tract (RVOT) stenting and balloon pulmonary valvotomy (BPV) have been reported. With the development of low-profile stents, an increasing clinician experience and more predictable outcome with both duct and RVOT stenting, these procedures have gained popularity as the preferred palliations for TOF at most centres. We reviewed the literature to analyse whether BPV for TOF palliation, a technique first reported three decades ago, still has a role in the present era of paediatric cardiac care. In this review, we have concluded that BPV has very specific indications in patients with TOF, with predominantly valvar pulmonary stenosis, and may be a preferred option over other palliative strategies in hypoxemic preterm or low-birth weight infants.

Use of cutting balloon for palliative treatment in tetralogy of Fallot

In tetralogy of Fallot, severe cyanosis due to insufficient pulmonary blood flow necessitates early intervention. The Cutting Balloon, developed for percutaneous coronary angioplasty, was used successfully for transcatheter incision and dilation of infundibular and valvar pulmonary stenosis in four patients with tetralogy of Fallot.

Tetralogy of Fallot

The optimal surgical approach and timing for patients with tetralogy of Fallot remain controversial. There are two options in current practice: a two-stage repair (an initial palliative aortopulmonary shunt at an early age followed by complete repair at an older age) or primary complete repair. There has been a trend towards primary repair at a young age, which can be attributed to advances in anesthetic and cardiac surgical techniques. Primary repair has several advantages. The correction can be done in one operation and shunt complications are avoided. Progressive right ventricular fibrosis, ventricular hypertrophy, and chronic hypoxia are avoided, which may reduce the incidence of late ventricular arrhythmias. However, surgical correction at a young age is associated with an increased incidence of transannular patching and consequent pulmonary regurgitation. Progressive pulmonary regurgitation is associated with late ventricular arrhythmias and sudden death. These consequences may be prevented by timely pulmonary valve replacement. Palliative procedures include an aortopulmonary shunt, balloon dilation of the right ventricular tract, and stent placement. Of these measures, the aortopulmonary shunt is preferred, as it results in a more predictable outcome. Complications associated with shunt placement include shunt occlusion, pulmonary artery distortion, and occasionally, volume overloading of the left ventricle and pulmonary circulation. Institutional and surgeon preferences exist for either surgical strategy, and ultimately are justifiable when they produce the best outcomes for the individual patient. The optimal surgical strategy has to be determined by large prospective randomized studies that compare the functional status of the pulmonary valve and the need for reoperation at long-term follow-up.