Tetralogy of Fallot With Absent Pulmonary Valve Treatment & Management

Updated: Nov 22, 2015
  • Author: Prema Ramaswamy, MD; Chief Editor: Howard S Weber, MD, FSCAI  more...
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Treatment

Approach Considerations

Pulmonary complications are the common cause of infant mortality in patient with tetralogy of Fallot (TOF) with absent pulmonary valve. In a neonate with respiratory distress, transfer to a tertiary care facility with pediatric critical care specialists, pediatric cardiologists, and pediatric cardiothoracic surgeons is expected.

Exacerbation of emphysematous changes and atelectasis from minor respiratory embarrassment, such as an upper respiratory infection, may cause severe problems in the affected neonate. Respiratory syncytial virus (RSV) infection is particularly hazardous for these patients.

Placing the infant in a prone position may be beneficial for respiratory effort; it has been reported to be helpful both preoperatively and postoperatively. [22] However, this sleeping position is not recommended unsupervised, because it increases risk of sudden infant death syndrome (SIDS). Takabayashi et al have recommended use of the prone position along with bilateral pillows to avoid compression of the sternum. [23]

Maturation of the tracheobronchial tree in infants older than 1 year reduces pulmonary obstructive symptoms, presumably by strengthening the underlying cartilaginous structures.

Patients with severe bronchial obstruction present a distinct management problem. If an infant develops respiratory acidosis with retention of carbon dioxide, assisted ventilation may be indicated; however, mechanical ventilation in these patients is of great concern, because once a patient is dependent on positive pressure ventilation, weaning from the respirator can be very difficult. If used, pressure settings should be as low as possible.

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Surgical Intervention

Critically ill patients require urgent surgical repair. Early surgical correction is preferred in symptomatic patients. [24] In asymptomatic infants and those with only mild symptoms, surgery is usually deferred until later in childhood. [25]

Consultation with a pediatric cardiologist and a pediatric cardiothoracic surgeon is essential.

Repair techniques and controversies

Surgical repair techniques vary in accordance with the particular anatomy in a given patient, especially the severity of pulmonary artery dilation. The repair depends on achieving integrity of pulmonary circulation, which one report suggests is best achieved by using right ventricle–to–pulmonary artery conduit or inserting a pulmonary valve. [24]

Definitive repair includes intracardiac repair of as well as the elimination of bronchial compression. Therefore, any intracardiac surgery needs to be accompanied with excision of the main, right, and left pulmonary arteries. [26] However, this is not always uniformly helpful because, as mentioned earlier, abnormalities may be present at the pulmonary arteriolar level.

Another area of controversy is whether to insert a valve in the pulmonic position via a homograft or a bioprosthetic valve conduit which typically degenerates (stenosis or insufficiency) fairly quickly in neonates. [18, 27, 28] However, one report argues that the use of a valveless right ventricle–to–pulmonary artery connection, combined with catheter-based intervention, reduces the likelihood of reoperation necessitated by homograft placement. [29]

Other approaches have been suggested to reduce the bronchial compression. One such approach includes translocation of the pulmonary artery anterior to the aorta and away from the airways. [30]

External airway stenting and intracardiac repair

Sakamoto et al described external stenting of the airway along with intracardiac repair, another ingenious approach. [31] This group placed a separate graft and patch around the respiratory tract. The authors pointed out that suturing the first graft on the border region between the cartilaginous portion and membranous portion is important and not to completely encircle the trachea, because this may then hamper growth of the airway. [31] They argued that external stenting of the airway was likely to be more effective than endobronchial stenting.

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Postoperative Monitoring

Airway morbidity dictates the postoperative recovery and prognosis of neonates from older patients with tetralogy of Fallot (TOF) with absent pulmonary valve. The overall survival is linked to the airway pathology, which is the cause of morbidity and mortality. Preoperative intubation and ventilation are risk factors predictive of poor outcome. (See Prognosis.)

Repair in the critically ill neonate is urgent, high risk, fraught with postoperative complications, and carries a high mortality rate. However, 2 surgical reviews provided a more optimistic picture when surgical strategies are individualized and combined with aggressive postoperative ventilatory management and additional interventions aiming to relieve airway obstruction. [25, 29]

Surgical repair of aneurysmal pulmonary arteries in infants does not necessarily eliminate respiratory symptoms due to persistent bronchial narrowing. These patients require close and regular outpatient follow-up.

Patients in whom repair is successful require regular outpatient visits to monitor right ventricular function, hemodynamics of the homograft, if used, and cardiac rhythm stability.

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