Tetralogy of Fallot With Pulmonary Atresia Treatment & Management

Neonates with adequate-sized confluent pulmonary arteries may be amenable to primary definitive surgical repair. A palliative procedure with a systemic–to–pulmonary artery shunt may be performed while awaiting complete repair at a later date. The ultimate surgical goals are: (1) to incorporate as many pulmonary artery segments as possible into a pulmonary artery confluence, (2) to place a conduit from the right ventricle to the pulmonary artery confluence, and (3) to close the ventricular septal defect (VSD).

Hypoplastic pulmonary arteries

When the pulmonary arteries are hypoplastic, nonconfluent, and supplied by aortopulmonary collaterals, a multistaged repair is often required.^[17] Hypoplastic pulmonary arteries generally require palliative shunting to induce enlargement and growth of these vessels so they can be successfully incorporated into the complete repair. The shunts used may be modified Blalock-Taussig or central shunts and may be unilateral or bilateral. Another important strategy to maximize the long-term outcome in this group of patients is the early unifocalization of as many of the aortopulmonary collaterals as possible into a central pulmonary artery confluence.^{[18, 19]} This maximizes the recruitment of lung segments and increases the likelihood of performing the definitive repair.

Complete repair following palliation

For complete repair to be performed in a child who has undergone palliation: (1) The central pulmonary arterial area must be greater than 50% of normal; (2) predominantly left-to-right intracardiac shunting must be present; (3) the equivalent of an entire lung must be supplied by the central pulmonary artery confluence; and (4) stenotic lesions in the pulmonary artery outflow must be addressed.

The choice of the optimal type of conduit for a growing child remains controversial. Current options include cryopreserved aortic or pulmonary homografts, glutaraldehyde fixed bovine jugular vein grafts, and synthetic conduits, with variable intermediate-term results reported in the medical literature.^{[20, 21, 22]} Patients with membranous pulmonary atresia may be amenable to repair using a pulmonary transannular patch. These patients have an improved freedom from reintervention compared with patients who receive right ventricle-to-pulmonary artery conduit.^[23]

Significant pulmonic valve regurgitation often occurs regardless of the type of conduit placed between the right ventricle and the pulmonary arteries. Some patients develop substantial right ventricular dilation and right ventricular dysfunction. Surgical placement of a pulmonic valve may significantly benefit these patients. More recently, a transcatheter-placed pulmonary valve comprising a valved segment of bovine jugular vein sewn within a balloon-expandable stent has been made commercially available. This valve can be placed in patients with postoperative conduit dysfunction consisting of pulmonary regurgitation, obstruction, or both. Early results with this valve suggest a high rate of procedural success and encouraging short-term valve function.^[24]

Single-stage repair

Some centers have shifted toward performing a single-stage repair, wherein all the multiple aortopulmonary collaterals (MAPCAs) are ligated at the aorta.^{[25, 26]} These MAPCAs are then mobilized toward the posterior mediastinum to construct a pulmonary artery confluence, followed by insertion of a pulmonary allograft to establish continuity between these neopulmonary arteries and the right ventricle. The ventricular septal defect (VSD) is closed.

These centers have reported good results. Infants with postunifocalization pulmonary arteries that, combined, are only mildly hypoplastic (> 200 mm²/m²) have a lower mortality rate and acceptable right ventricular pressures. However, most patients require repeat catheterizations for balloon dilation or stent placements in stenotic pulmonary artery segments to alleviate elevated right ventricular pressures.

The following consultations are advised:

• Pediatric cardiology consultation
• Geneticist consultation to evaluate the presence of syndromic associations and gene deletions, especially in the presence of associated anomalies or dysmorphic features
• Cardiovascular surgical consultation, once the anatomy of a child with tetralogy of Fallot with pulmonary atresia (TOF-PA) is determined by echocardiography and angiography findings (see Workup);the caregivers need to be aware of the possibility of a multistage repair and repeated surgeries and catheterizations
• Consultations and follow-up with the appropriate specialists for anomalies involving other systems

Infants with multiple aortopulmonary collaterals may require outpatient medical management of heart failure.

Residual right ventricular hypertension with right ventricular dysfunction from hypoplastic pulmonary arteries may be present.

After each stage of surgical reconstruction, echocardiographic and Doppler ultrasonic evaluation of hemodynamic adequacy should be performed. After complete repair, the patient needs to be evaluated for the development of right ventricle–to–pulmonary artery conduit stenosis as well as pulmonic regurgitation.

Some patients may never reach the stage of complete repair because of very hypoplastic pulmonary arteries. These patients often are hypoxemic and polycythemic and may require oxygen supplementation. Patients who are chronically cyanotic should be carefully monitored for complications related to polycythemia and iron deficiency anemia.

Admit patients with tetralogy of Fallot with pulmonary atresia (TOF-PA) for testing and surgical intervention. Transfer to a tertiary care center is indicated for complete diagnostic evaluation and surgical intervention.

Newborn infants with cyanosis due to congenital heart disease almost always benefit from administration of prostaglandin E1 (PGE1) to maintain ductal patency while a definitive diagnosis is made. Once the diagnosis of tetralogy of Fallot with pulmonary atresia (TOF-PA) is made, maintain PGE1 infusion through the initial surgery.

Older infants with increased pulmonary blood flow may require treatment for heart failure.

All patients with tetralogy of Fallot with pulmonary atresia are required to take appropriate antibiotic bacterial endocarditis prophylaxis.

Nutritional support

Infants who are born with multiple systemic-to-pulmonary collaterals and are in cardiac failure because of pulmonary overcirculation require caloric supplementation to establish a normal growth pattern. Caloric intake as high as 130-150 kcal/kg/d may be required to ensure adequate growth.

Children that undergo palliative procedures also require optimization of their caloric intake. Adequate nutritional supplementation in the form of total parental nutrition must also be ascertained in the perioperative period. These patients often have a prolonged postoperative recovery course.