Tricuspid Atresia Treatment & Management

The following three considerations guide the treatment of infants with tricuspid atresia:

• The amount of pulmonary blood flow must be regulated in order to decrease hypoxemia or symptoms of congestive heart failure.

• Myocardial function, the integrity of the pulmonary vascular bed, and pulmonary vascular integrity must be preserved in order to optimize conditions for a later Fontan operation.

• The risk of bacterial endocarditis and thromboembolism must be minimized.

The treatment of these children must be coordinated with a pediatric cardiac surgeon, pediatric cardiologist, neonatologist, and pediatric pulmonologist/intensivist. 

Routinely initiate prophylaxis against bacterial endocarditis when any invasive or dental procedure is contemplated.

The cohort of infants with decreased pulmonary blood flow encompasses most of the infants with tricuspid atresia. Marked cyanosis and hypoxemia characterize the clinical course. Acidemia may occur if the hypoxemia is profound, and death can ensue. Promptly treat infants with severe hypoxemia with prostaglandin E infusions in order to maintain patency of the ductus arteriosus and improve pulmonary blood flow.

Infants with increased pulmonary blood flow have an associated unrestrictive ventricular septal defect and transposed great vessels. They present with severe congestive heart failure and benefit from digitalis and diuretic therapy until an operative intervention can be undertaken to restrict the pulmonary blood flow.

The intelligent application of palliative procedures to control the amount of pulmonary blood flow in this lesion improves the survival of infants with tricuspid atresia. With standard palliative procedures, 50% of these infants can survive into their teen years. Nonetheless, these children are at risk for developing complications of the disease, including paradoxical emboli, stroke, brain abscess, polycythemia, progressive cardiac dilatation, ventricular dysfunction, mitral valve insufficiency, and arrhythmias.

Most patients with tricuspid atresia require some form of surgical treatment during the first year of life. Cyanosis with decreased pulmonary blood flow is the most common indication for surgical intervention. In this instance, a shunt procedure is undertaken to connect the systemic circulation to the pulmonary circulation. The shunt can be from the subclavian artery to the pulmonary artery (Blalock-Taussig shunt) or a cavopulmonary anastomosis (Glenn shunt). In patients with severe congestive heart failure indicative of increased pulmonary blood flow, pulmonary artery banding may be required to decrease the blood flow to the lungs and to assist with treatment of the accompanying congestive heart failure. ^{[11, 12]}

In an investigation of the association between surgical management of pulmonary blood flow at initial and staged procedures with survival to Fontan/Kreutzer operation in patients with tricuspid atresia, Wilder et al studied 302 infants with tricuspid atresia type I. They used multiphase parametric-hazard models to analyze competing outcomes among patients who underwent systemic to pulmonary artery shunt (SPS), pulmonary artery banding (PAB), or superior cavopulmonary connection (SCPC). Based upon the results, the investigators conclude that tricuspid atresia patients with SPS are a high-risk subgroup and that avoiding open ductus arteriosus and concomitant main pulmonary artery (MPA) intervention during SPS may help to mitigate the risk associated with SPS. ^[13]

In a study of the influence of morphology and initial surgical palliation strategy on the survival of infants with tricuspid atresia, Alsoufi et al found that multistage palliation outcomes of various tricuspid atresia subtypes are comparable and generally good, except for patients who have associated genetic/extracardiac anomalies. They found that the bulk of patient mortality is interstage. This emphasizes the ongoing need for improved monitoring and patient management during this period. ^[14]

Recurrence of the cyanosis, progressive polycythemia, decreasing exercise tolerance, shunt failure, or increasing pulmonary obstruction are indications for re-evaluation and consideration of a second operative procedure. A Fontan procedure is undertaken if the criteria are met; otherwise, a second palliative procedure should be performed.

The Fontan operation excludes the right ventricle through the formation of a right atrial-to-pulmonary artery connection or an extracardiac cavopulmonary anastomosis using a synthetic graft. Several parameters should be met to ensure a successful outcome. ^[15] Note the following:

• The candidate should be aged 4 years or older.

• A right atrium of normal volume and normal caval drainage should be present.

• Sinus rhythm should be present.

• Mean pulmonary artery pressure should be low (ie, < 15 mm Hg), as should mean pulmonary arteriolar resistance.

• The pulmonary artery-to-aorta diameter ratio should be greater than 0.75.

• Previous shunt procedures should not exert impairing effects.

  Tricuspid Atresia. Fontan procedure: Illustration of the atrial-to-pulmonary artery anastomosis.

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• In a subset of patients with a single functional ventricle and cardiac abnormalities, including tricuspid atresia, pulmonary atresia with intact ventricular septum, and double outlet right ventricle, a 3-stage Fontan pathway without cardiopulmonary bypass may be achievable and safe. ^[16]

• The operative procedure connects the right atrium to the systemic pulmonary artery system at the outflow tract or at the bifurcation of the main trunk. Any atrial septal defect is closed. ^{[17, 18, 19, 20, 21, 22, 23, 24]}

Complications

Complications from a shunt procedure can include too much pulmonary blood flow. The shunt can also cause damage to the pulmonary arteriolar tree.

Complications from the Fontan procedure include pulmonary edema, congestive hepatopathy, pleural effusions, ascites, protein-losing enteropathy, and cardiac arrhythmias.

Further inpatient care

Because pulmonary blood flow is of paramount importance in patients with tricuspid atresia, carefully monitor for signs of hypoxemia or fluid overload. After a palliative procedure, perform echocardiographic assessments to determine the patency of the shunt. Clinical evaluation is of benefit to determine instances of increased pulmonary blood flow that require treatment for ensuing congestive heart failure. Signs of hypoxemia in the form of rising hemoglobin levels must be monitored carefully because onset is insidious.

Inpatient care after the Fontan procedure requires careful monitoring of pulmonary vascular resistance, heart rhythm, and fluid status. All efforts are made to maintain pulmonary vascular resistance as low as possible using supplemental oxygen and pulmonary vasodilators. Maintaining normal sinus rhythm in these patients optimizes cardiac output and ensures a favorable outcome. These patients characteristically develop pleural effusions after the procedure, which must be monitored carefully and removed in order to maximize oxygenation and decrease pulmonary vascular resistance.

Carefully examine the child for signs of hepatic congestion. Hepatic congestion can occur secondary to the operative procedure and the subsequent volume overload. Treatment consists of diuretic therapy.

Because of the volume overload present in these children and the use of diuretics, a low-sodium diet should be prescribed. Be attentive to replacement of appropriate electrolytes and the maintenance of nutrition to foster proper growth and development. Counsel the parents of these children about dietary sodium restriction, as well as the signs and symptoms of hypoxemia and congestive heart failure.

Encourage activity in these children, who often limit activities secondary to the presence of dyspnea from congestive heart failure.

For patients who have undergone a palliative procedure, arrange careful follow-up to monitor pulmonary blood flow. Increasing polycythemia and cyanosis are indicative of poor shunt flow and may indicate that another procedure is needed to prevent worsening hypoxemia.

Increased pulmonary blood flow is detrimental in this population; monitor carefully, watching for signs of congestive heart failure.

For patients who have had the Fontan procedure, maintain follow-up care to ensure a stable cardiac rhythm. Consider careful assessment of ventricular function on a routine basis. These patients may develop signs of congestive heart failure and congestive hepatopathy in the early postoperative course. In such instances, institute diuretic therapy early in order to preserve pulmonary blood flow and oxygenation.