Pulmonary Artery Banding

Pulmonary artery banding (PAB) is a technique of palliative surgical therapy used by congenital heart surgeons as a staged approach to operative correction of congenital heart defects. This technique was widely used in the past as an initial surgical intervention for children born with cardiac defects characterized by left-to-right shunting and pulmonary overcirculation. Within the last decade, early definitive intracardiac repair has largely replaced palliation with pulmonary artery banding. This trend has evolved because many centers have demonstrated improved outcomes with primary corrective surgery as an initial intervention in the neonate with congenital heart disease. Although the use of pulmonary artery banding has recently significantly decreased, it continues to maintain a therapeutic role in certain subsets of patients with congenital heart disease.

The primary objective of performing pulmonary artery banding is to reduce excessive pulmonary blood flow and protect the pulmonary vasculature from hypertrophy and irreversible pulmonary hypertension. More recently, pulmonary artery banding has played a role in the preparation and “training” of the left ventricle (LV) in patients with D-transposition of the great arteries (d-TGA) who are evaluated for a delayed arterial switch procedure. It has found a similar role in training the LV in patients with L-transposition of the great arteries (L-TGA) who may also be candidates for an arterial switch procedure.

Safe placement of a pulmonary artery band: (A) encircling the aortopulmonary trunk, (B) encircling the aorta, and (C) completing the pulmonary artery band at the final location.
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Safe placement of a pulmonary artery band: (A) encircling the aortopulmonary trunk, (B) encircling the aorta, and (C) completing the pulmonary artery band at the final location.

History of the Procedure
The first description of pulmonary artery banding in the literature was a report by Muller and Dammann at the University of California, Los Angeles (UCLA) in 1951.1 In this report, Muller and Dammann described palliation by the “creation of pulmonary stenosis” in a 5-month-old infant who had a large ventricular septal defect (VSD) and pulmonary overcirculation. Following this report, multiple studies were published demonstrating the effectiveness of this technique in infants with congestive heart failure (CHF) caused by large VSDs, complex lesions (eg, atrioventricular canal [AVC] defects), and tricuspid atresia.2,3,4,5,6,7,8,9,10,11 Although the use of pulmonary artery banding has declined, it remains an essential technique for comprehensive surgical treatment in patients with congenital heart disease.

Pathophysiology
Congenital heart defects with left-to-right shunting and unrestricted pulmonary blood flow (PBF) due to a drop in pulmonary vascular resistance result in pulmonary overcirculation. In the acute setting, this leads to pulmonary edema and CHF in the neonate. Within the first year of life, this unrestricted flow and pressure can lead to medial hypertrophy of the pulmonary arterioles and fixed pulmonary hypertension. Pulmonary artery banding creates a narrowing, or stenosing, of the main pulmonary artery (MPA) that decreases blood flow to the branch pulmonary arteries and reduces PBF and pulmonary artery pressure. In patients with cardiac defects that produce left-to-right shunting, this restriction of PBF reduces the shunt volume and consequently improves both systemic pressure and cardiac output. A reduction of PBF also decreases the total blood volume returning to the LV (or the systemic ventricle) and often improves ventricular function.

Pulmonary artery banding may not be tolerated in patients who have cardiac defects that depend on mixing of the systemic and pulmonary venous blood to maintain adequate systemic oxygen saturations. This is particularly true if a restrictive communication is present between the 2 atria. Therefore, ensuring that such patients have an unrestricted atrial communication is important to allow adequate mixing at the atrial level before proceeding with pulmonary artery banding. This can be accomplished with a balloon atrial septostomy or an operative atrial septectomy at the time of pulmonary artery banding.

Indications
Currently, the patients who are selected for pulmonary artery banding (PAB) and staged cardiac repair are determined based on the experience and philosophy of the pediatric cardiologists and congenital heart surgeons at any given institution. Most of these patients fall into 2 broad categories: (1) those with pulmonary overcirculation and left-to-right shunting who require reduction of pulmonary blood flow (PBF) as a staged approach to more definitive repair and (2) those with transposition of the great arteries (TGA) who require training of the left ventricle (LV) as a staged approach to the arterial switch procedure.

Patients in the first category who are considered for pulmonary artery banding include those with the following diagnoses:
Multiple muscular ventricular septal defects (VSDs) with a “Swiss cheese” septum that is technically difficult to repair in the neonate or requires a ventriculotomy
Single or multiple VSDs with coarctation of the aorta or interrupted aortic arch
Single ventricle defects (eg, tricuspid atresia) that are associated with increased PBF in the neonate
Unbalanced atrioventricular canal (AVC) defects in which the LV is hypoplastic but the potential exists for a 2-ventricle repair with further growth and development12
Cardiac defects that require a homograft conduit (eg, D-TGA with subpulmonic stenosis requiring a Rastelli-type repair) for complete repair: Use of pulmonary artery banding may allow time for growth of the patient before the complete repair. The interim growth of the patient permits placement of a larger conduit at the time of repair and potentially increases the longevity of the conduit and the length of freedom from reoperation. With current clinical practice, most patients with D-TGA pulmonary stenosis (PS) undergo a Rastelli procedure and placement of a right ventricle (RV)–to–pulmonary artery (PA) conduit. If a staged repair is indicated, a pulmonary artery banding is not usually performed because of already decreased pulmonary blood flow. In this situation, a systemic-to-pulmonary shunt is performed.
Patients in the second category who are considered for pulmonary artery banding include those with the following diagnoses:
D-TGA that requires preparation of the LV for an arterial switch procedure following initial late presentation or diagnosis in patients older than 1 month
D-TGA that requires preparation of the LV for an arterial switch procedure following a previous Mustard or Senning procedure with the development of right ventricular failure or L-TGA that requires preparation of the LV prior to the arterial switch procedure.
Note that patients with single ventricle physiology and unrestricted PBF are suitable for an early pulmonary artery banding to prevent the development of congestive heart failure (CHF) and pulmonary hypertension. This group of patients may include those who have tricuspid atresia with unrestrictive VSD, unbalanced AVC defect, and double inlet LV.13 In one reported series, 9 of 20 patients with double inlet LV demonstrated severe PA medial hypertrophy on histologic examination within one year of life.14 Generally, patients who have single ventricle physiology and pulmonary overcirculation should undergo PAB in the first 1-2 months of life to avoid irreversible pulmonary hypertension that may complicate or preclude a subsequent Fontan procedure.

Currently, most patients with D-TGA undergo an arterial switch procedure within the first few weeks of life. However, some newborns with D-TGA and an intact ventricular septum may not undergo an early arterial switch procedure because of active infections, coexistent noncardiac diseases, or a delay in diagnosis. A recent study concluded that aprotinin reduced postoperative blood loss in arterial switch procedures in infants.15

In the past, patients who did not undergo early an arterial switch procedure were treated by a Mustard or Senning procedure because the arterial switch was precluded by rapid involution of the left ventricular myocardium. Subsequent experience demonstrated that neonatal pulmonary artery banding and concomitant systemic-to-PA shunt resulted in preservation of the LV and reversal of any attenuation of the myocardium, leading to successful arterial switch later in infancy.16,17

Pulmonary artery banding is also used in patients with D-TGA who develop right ventricular dysfunction after a Mustard or Senning atrial switch procedure. The pulmonary artery banding is required for a longer period than preparation of the ventricle in infants (<12 mo). Although the overall early survival rate approaches 90%, approximately one half of these patients require heart transplantation because of the progression of coexisting left ventricular failure.18 Furthermore, a high prevalence of significant neo-aortic valve insufficiency is noted in patients who successfully undergo the arterial switch procedure.

Recent application of pulmonary artery banding has been reported