Pulmonary Artery Banding: Encircling the Main PA

Pulmonary artery banding (PAB) is a palliative operation that creates a controlled obstruction of the main pulmonary artery (MPA) to reduce pulmonary blood flow and distal pulmonary arterial pressure. Although primary repair has replaced PAB for many simple congenital heart defects, banding remains useful in selected infants in whom immediate definitive repair is undesirable or anatomically impractical, including patients with complex intracardiac anatomy, multiple ventricular septal defects, very low body weight, selected single-ventricle pathways, or circumstances in which time is required before definitive reconstruction.[1,2]

The technical concept is simple: encircle the MPA, progressively tighten the band while assessing its physiologic effect, and secure it without distortion or migration. In practice, however, the operation requires careful control of band position, geometry, and tightness because relatively small changes in circumference can substantially alter pulmonary blood flow and right ventricular afterload.

1. Physiologic Objective

The principal objective of conventional PAB is to convert an unrestricted pulmonary circulation into a controlled-resistance circuit. In a patient with a large systemic-to-pulmonary shunt, decreasing the effective diameter of the MPA reduces pulmonary blood flow, lowers distal pulmonary artery pressure, decreases pulmonary venous return, and relieves left-sided volume loading. Over time, this may permit somatic growth while limiting pulmonary vascular exposure to excessive flow and pressure.[1,2]

PAB is therefore not defined by a particular Doppler gradient. The appropriate degree of restriction depends on the underlying anatomy and circulation. Relevant endpoints include:

• distal pulmonary artery pressure relative to systemic arterial pressure;
• systemic arterial oxygen saturation;
• systemic blood pressure and cardiac output;
• ventricular function and atrioventricular valve competence;
• the amount of intracardiac mixing;
• pulmonary venous and systemic venous pressures; and
• the planned subsequent stage of repair or palliation.

For a biventricular circulation with pulmonary overcirculation, a distal pulmonary arterial systolic pressure approximately 30–50% of systemic pressure has historically been used as a physiologic target.[2] This should be regarded as a guide rather than a universal endpoint. In lesions with mixing physiology, excessive restriction may cause unacceptable systemic desaturation, whereas an apparently adequate band gradient may still permit excessive pulmonary blood flow if systemic pressure, pulmonary vascular resistance, or ventricular output changes.

The relationship between band diameter and gradient is also dynamic. Immediately after banding, pulmonary vascular resistance, anesthesia, ventilation, vasoactive support, hematocrit, and loading conditions all affect the measured gradient. Postoperative Doppler gradients therefore should not be expected to reproduce exactly the intraoperative measurement.

2. Operative Exposure

PAB is most commonly performed through a median sternotomy, particularly when associated procedures may be required or when optimal access to the great arteries is desired. After sternotomy, the pericardium is opened and suspended to expose the right atrium, right ventricle, ascending aorta, and MPA. The supplied operative sequence begins with this standard exposure before the band is routed around the MPA. PA Banding Surgical Technique -…

Cardiopulmonary bypass is generally unnecessary for isolated PAB. Avoiding bypass remains one of the potential advantages of the procedure in fragile infants. Nevertheless, the surgeon should anticipate whether associated anatomy or instability could make bypass necessary.

The MPA, pulmonary valve, pulmonary bifurcation, and proximal right and left pulmonary arteries should be clearly understood before the band is positioned. Extensive circumferential dissection of the MPA is usually unnecessary and may increase tissue trauma. The objective is to create a safe passage for the band while preserving the pulmonary arterial adventitia and avoiding injury to adjacent structures.

3. Passing the Band Through the Transverse Sinus

A narrow prosthetic tape is commonly used for conventional PAB. Various materials and widths have been described; the specific material is less important than achieving a smooth, stable, nontraumatic constriction.

The illustrated technique passes the band through the transverse sinus, posterior to the ascending aorta and anterior to the pulmonary arteries. PA Banding Surgical Technique -…

This route allows the band to be brought beneath the ascending aorta and around the MPA without requiring aggressive circumferential mobilization of the pulmonary trunk.

The passage should be performed under direct control. The transverse sinus is developed sufficiently to permit atraumatic passage, and the band should remain flat rather than twisted. Resistance should not be overcome blindly. Particular care is required in patients with unusual great-artery relationships, markedly dilated pulmonary arteries, prior surgery, or distortion related to the underlying congenital lesion.

4. Encircling the Main Pulmonary Artery

The band is then passed under the ascending aorta and brought around the MPA. PA Banding Surgical Technique -… The completed loop should sit on the pulmonary trunk rather than on the pulmonary valve proximally or pulmonary bifurcation distally.

Band position is critical. If placed too proximally, constriction may distort the pulmonary annulus or valve. If placed too distally, the band may impinge on one branch pulmonary artery, particularly if it subsequently migrates. Branch pulmonary artery distortion and band migration are well-recognized complications of conventional PAB.[1–3]

Before tightening, several features should therefore be confirmed:

Band orientation. The tape should lie flat against the MPA without folding or twisting.

Proximal clearance. There should be adequate distance from the pulmonary valve to minimize annular or valvar distortion.

Distal clearance. The band should remain proximal to the pulmonary bifurcation, with unobstructed origins of both branch pulmonary arteries.

Freedom from adjacent structures. The band must encircle only the intended pulmonary arterial segment.

These apparently minor geometric details have important long-term consequences because the band may remain in place for months while the child and pulmonary arteries grow.

5. Initial Band Calibration

Historical formulas are useful for estimating an initial circumference but should not substitute for physiologic assessment. Trusler and colleagues established weight-based principles for PAB calibration that became widely adopted.[3] Subsequent investigators have modified these formulas according to anatomy and institutional experience.

For example, Nagashima and colleagues reported using a 3-mm polyester tape tightened to a circumference of:

19 mm + 1 mm/kg body weight

in 38 acyanotic neonates and infants, including 15 weighing less than 2.5 kg. There were no early deaths, and most survivors subsequently underwent intracardiac repair.[4] This illustrates the usefulness of weight-based calibration as a starting point, but it does not establish a universal circumference applicable to all lesions.

Anatomy matters substantially. A patient with complete intracardiac mixing can tolerate a different pulmonary-to-systemic flow ratio from a patient with an isolated large VSD. Likewise, a single-ventricle patient being prepared for later cavopulmonary palliation has different physiologic requirements from an infant undergoing temporary palliation before biventricular repair.

6. Progressive Tightening

Once the MPA has been encircled, the band is progressively tightened rather than immediately fixed at a predetermined circumference. PA Banding Surgical Technique -…

During tightening, the surgical and anesthesia teams should continuously assess the response. Useful measurements include systemic arterial pressure, arterial oxygen saturation, distal pulmonary artery pressure when directly monitored, ventricular function, and transband gradient by echocardiography.

The desired endpoint is a physiologically satisfactory balance between adequate pulmonary restriction and preserved systemic output.

Several responses suggest excessive tightening:

• abrupt or profound desaturation beyond that expected from the anatomy;
• systemic hypotension;
• deterioration in ventricular function;
• increasing atrioventricular valve regurgitation;
• significant bradycardia or other hemodynamic instability;
• excessive right ventricular pressure loading.

Conversely, persistent pulmonary overcirculation, high distal PA pressure, minimal reduction in pulmonary venous return, or a very low transband gradient may indicate inadequate restriction.

The final decision should integrate pressure, flow, saturation, and ventricular performance, rather than relying on any single parameter.

7. Securing the Band

After satisfactory calibration, the band is secured to maintain the selected circumference. The illustrated technique uses sutures to prevent subsequent displacement. PA Banding Surgical Technique -…

Fixation to the pulmonary arterial adventitia is important because an unsecured band can migrate distally as the heart moves and the child grows. Distal migration may narrow one or both branch pulmonary arteries and has historically been associated with substantial morbidity.[1,5]

The fixation sutures should stabilize the band without penetrating deeply into the pulmonary arterial wall or compromising the lumen. The surgeon should again inspect the right and left pulmonary artery origins after fixation because appropriate restriction at the MPA is of limited value if associated focal branch obstruction has been created.

Techniques allowing more precise intraoperative calibration have also been described. Prêtre and colleagues used clips for incremental adjustment, followed by sutures to stabilize the band, emphasizing both accurate titration and later ease of removal.[6]

8. Completion Assessment

Before chest closure, the band should be assessed as both a hemodynamic intervention and an anatomic reconstruction.

Echocardiography should evaluate the band position, velocity across the restriction, proximal and distal MPA, branch pulmonary arteries, pulmonary valve, ventricular function, and atrioventricular valve regurgitation. In lesions with intracardiac mixing, the adequacy of interatrial or interventricular communication must also be considered.

The final gradient should be interpreted in the context of systemic pressure. Because the gradient is flow-dependent, an apparently satisfactory value during reduced cardiac output may increase substantially as cardiac output improves.

Direct measurement of distal PA pressure, when available, can provide additional information that is not captured by Doppler velocity alone.

9. Postoperative Physiology and Surveillance

Postoperative management focuses on ensuring that the intended pulmonary-to-systemic balance persists as anesthesia resolves and pulmonary vascular resistance changes.

A band that appears relatively loose immediately after surgery may become more restrictive as pulmonary blood flow increases, whereas changes in ventricular output can alter the measured gradient independently of band geometry. Serial assessment should therefore integrate oxygen saturation, respiratory status, systemic perfusion, feeding and growth, radiographic pulmonary vascularity, and echocardiography.

Longer-term complications of conventional PAB include band migration, branch pulmonary artery stenosis or distortion, pulmonary arterial wall injury, pulmonary valve distortion or regurgitation, excessive right ventricular hypertrophy, and the need for pulmonary artery reconstruction at definitive repair.[1,2,5] Earlier historical series demonstrate why PAB cannot be regarded as a biologically neutral temporizing procedure.[7]

Adjustable and dilatable systems were developed to address the difficulty of maintaining an optimal restriction as physiology and body size change. Telemetrically adjustable devices have demonstrated repeated nonoperative adjustment in selected patients,[8] while more recent surgically implanted bands designed for subsequent transcatheter balloon dilation have similarly shown feasibility.[9] These techniques are center-specific rather than a universal replacement for conventional banding.

10. Key Surgical Principles

• Position matters as much as tightness. The band should remain on the MPA, away from both the pulmonary valve and pulmonary bifurcation.
• Use the transverse sinus for controlled passage. Routing the tape behind the ascending aorta permits atraumatic encirclement of the MPA with limited dissection.
• Keep the band flat. Twisting or folding creates unpredictable focal compression.
• Use formulas only as a starting point. Final calibration must reflect the patient's anatomy and physiology.
• Tighten progressively. Evaluate systemic pressure, oxygen saturation, distal PA pressure, ventricular function, and echocardiographic findings during adjustment.
• Secure the band against migration. Fixation should prevent displacement without injuring the pulmonary arterial wall.
• Assess both branch pulmonary arteries before completion. Iatrogenic branch PA distortion should prompt immediate correction.
• Expect physiology to change postoperatively. A band gradient is flow-dependent and should never be interpreted in isolation.

References

1. Angeli E, Pace Napoleone C, Turci S, Oppido G, Gargiulo G. Pulmonary artery banding. Multimed Man Cardiothorac Surg. 2012. doi:10.1093/mmcts/mms010. PMID: 24414714.
2. Sharma R. Pulmonary artery banding: rationale and possible indications in the current era. Ann Pediatr Cardiol. 2012. doi:10.4103/0974-2069.93709. PMID: 22529600.
3. Albus RA, Trusler GA, Izukawa T, Williams WG. Pulmonary artery banding. J Thorac Cardiovasc Surg. 1984. doi:10.1016/S0022-5223(19)35431-5. PMID: 6208431.
4. Nagashima M, Okamura T, Shikata F, Chisaka T, Takata H, Ohta M, Yamamoto E, Higaki T. Pulmonary artery banding for neonates and early infants with low body weight. Tohoku J Exp Med. 2011. doi:10.1620/TJEM.225.255. PMID: 22095252.
5. Vérel D, Taylor DG, Emery JL. Failure of pulmonary artery banding due to migration of the band. Thorax. 1970. doi:10.1136/thx.25.1.126. PMID: 5418006.
6. Prêtre R, Benedikt P, Turina M. Precise adjustment of a band on the main pulmonary artery. Thorac Cardiovasc Surg. 2000. doi:10.1055/S-2000-8887. PMID: 10757160.
7. Hunt CE, Formanek G, Levine MA, Castaneda AR, Moller JH. Banding of the pulmonary artery: results in 111 children. Circulation. 1971. doi:10.1161/01.CIR.43.3.395. PMID: 5101742.
8. Bonnet D, Corno AF, Sidi D, Sekarski N, Beghetti M, Schulze-Neick I, et al. Early clinical results of the telemetric adjustable pulmonary artery banding FloWatch-PAB. Circulation. 2004. doi:10.1161/01.CIR.000138222.43197.1e. PMID: 15364856.
9. Ligon RA, Latson LA, Ruzmetov MM, Chan KC, Turner I, Scholl F, Bibevski S. Dilatable pulmonary artery banding palliation in congenital heart disease. World J Pediatr Congenit Heart Surg. 2021. doi:10.1177/2150135120975763. PMID: 33684011.