Pulmonary Artery Banding #5: Main PA Banding—Technical Principles and Physiology-Guided Adjustment

1. Concept of Main Pulmonary Artery Banding

Main pulmonary artery banding (PAB) is a palliative operation that creates a controlled obstruction of the main pulmonary artery (MPA). Its principal purpose is to reduce excessive pulmonary blood flow, lower distal pulmonary arterial pressure, decrease pulmonary venous return and ventricular volume loading, and protect the pulmonary vascular bed until definitive repair or the next stage of palliation.

Although the procedure appears mechanically simple, successful PAB depends on achieving the correct physiologic degree of restriction. A band that is too loose fails to control pulmonary overcirculation, whereas an excessively tight band may cause profound desaturation, reduced cardiac output, ventricular dysfunction, or metabolic acidosis. Accordingly, no single band circumference, pressure gradient, or oxygen saturation should be considered universally appropriate. Band sizing must integrate anatomy, body size, circulatory pathway, pressure measurements, oxygenation, ventricular performance, and systemic perfusion [1,2].

The physiologic objectives also differ substantially between biventricular (BiV) and single-ventricle (SV) circulations. In a biventricular pathway, the dominant objective is generally to control a large left-to-right shunt. In a single-ventricle pathway, PAB must establish an appropriate balance between pulmonary and systemic blood flow while preparing the pulmonary vascular bed for subsequent cavopulmonary connection.

2. Hemodynamic Effects of Main PAB

In lesions with unrestricted pulmonary blood flow, falling pulmonary vascular resistance after birth may produce excessive pulmonary flow:

Large systemic-to-pulmonary communication → Qp >> Qs → pulmonary congestion → ventricular volume overload → heart failure

Placement of a main PA band adds a fixed resistance between the subpulmonary ventricle and distal pulmonary arterial circulation. This produces several simultaneous effects:

• Reduction in pulmonary blood flow (Qp)
• Reduction in distal pulmonary arterial pressure
• Reduction in pulmonary venous return
• Reduction in ventricular volume loading
• Increase in proximal pulmonary arterial and subpulmonary ventricular pressure
• Development of a pressure gradient across the band
• Potential reduction in systemic arterial oxygen saturation

The objective is not to maximize the pressure gradient across the band. Rather, the band should create sufficient restriction to protect the pulmonary circulation while maintaining adequate systemic cardiac output and oxygen delivery.

A loose band may leave persistent pulmonary edema, tachypnea, heart failure, elevated distal pulmonary pressure, and excessive ventricular preload. A tight band may cause excessive cyanosis, hypotension, inadequate pulmonary venous return, ventricular dysfunction, and impaired systemic oxygen delivery.

Therefore, the optimal PAB is defined by its physiologic effect, not by its absolute circumference.

3. Anatomic Position of the Band

The band should generally be positioned around the mid-main pulmonary artery, with adequate distance from both the pulmonary valve proximally and the pulmonary artery bifurcation distally.

Proximal consideration: pulmonary valve

A band placed too close to the pulmonary valve may distort the pulmonary root or interfere with leaflet motion. Pulmonary valve distortion is a recognized complication of PAB [1]. The band should therefore be positioned sufficiently distal to avoid direct annular or valvar impingement.

Distal consideration: branch pulmonary arteries

Conversely, excessive distal placement or subsequent distal migration can distort the origins of the right or left pulmonary artery. Branch PA distortion is particularly undesirable because residual stenosis may remain after later debanding and may require pulmonary artery reconstruction.

The ideal relationship is therefore:

Pulmonary valve → adequate proximal MPA → PAB → adequate distal MPA → RPA/LPA bifurcation

After the optimal position has been selected, fixation sutures should secure the band to the pulmonary arterial adventitia to minimize migration.

4. Initial Band Circumference: A Starting Point, Not an Endpoint

Traditional PAB techniques have frequently used body-weight–based formulas to estimate the initial circumference. The classic Trusler approach provides a practical starting point, and a circumference of approximately:

Body weight (kg) + 20 mm

has traditionally been used in acyanotic, high-pulmonary-flow physiology [1].

However, this calculation should not be interpreted as a mandatory final circumference. Durandy emphasized that formula-based sizing is useful only as a guideline because the relationship between external band circumference and physiologic restriction varies considerably among patients [2].

Important determinants include:

• Native MPA diameter and geometry
• Patient weight and age
• Pulmonary vascular resistance
• Size and location of intracardiac communications
• Systemic vascular resistance
• Ventricular systolic and diastolic function
• AV valve competence
• Degree of intracardiac mixing
• Hemoglobin concentration
• Anesthetic depth
• Mechanical ventilation and airway pressure
• Inotropic or vasoactive support

Thus, two infants of identical weight may require substantially different final band circumferences.

The formula should therefore answer the question “Where should adjustment begin?”, rather than “What must the final circumference be?”

5. Physiology-Guided Intraoperative Adjustment

The band should be tightened progressively while the operative team evaluates the hemodynamic response.

Before tightening, baseline measurements should ideally include:

• Systemic arterial pressure
• Systemic oxygen saturation
• Heart rate and rhythm
• Distal pulmonary arterial pressure when available
• Ventricular function
• Evidence of systemic perfusion

After each incremental adjustment, the circulation should be allowed to stabilize before further tightening. Manipulation of the heart, changes in ventilation, vasoactive medications, and transient changes in systemic vascular resistance can substantially alter the apparent response.

Useful intraoperative variables include the proximal-to-distal PA pressure gradient, the relationship between systemic and distal pulmonary arterial pressures, and pulse oximetry [2]. None is sufficient in isolation.

A successful adjustment should generally produce:

↓ Qp → ↓ distal PAP → ↓ pulmonary venous return → improved balance of systemic and pulmonary flow

without hypotension, ventricular deterioration, or unacceptable reduction in oxygen delivery.

6. Distal Pulmonary Arterial Pressure in Biventricular Circulation

For biventricular circulation, the conventional target after PAB is a distal pulmonary arterial pressure approximately 30–50% of systemic arterial pressure [1].

This range is more appropriately regarded as a physiologic reference than an absolute target. The appropriate pressure depends on the underlying lesion, pulmonary vascular resistance, systemic arterial pressure, ventricular function, and the duration for which the band is expected to remain in place.

For example, an infant with a large VSD and severe pulmonary overcirculation may tolerate substantial reduction in pulmonary pressure while maintaining excellent systemic oxygenation. Conversely, a patient with more complex intracardiac mixing may become significantly desaturated before a predetermined pressure ratio is reached.

Thus:

Pressure target + oxygenation + systemic perfusion + ventricular function

should determine the final band tightness.

A satisfactory pressure ratio should never be pursued at the expense of hemodynamic stability.

7. Main PAB in a Biventricular Pathway

Main PAB may be used as staged palliation when immediate complete biventricular repair is undesirable or associated with excessive risk.

Potential settings include selected patients with:

• Large VSD
• Multiple or muscular VSDs
• Complete or transitional AVSD
• Complex intracardiac anatomy
• Significant associated systemic outflow or aortic arch reconstruction
• Clinical conditions in which definitive repair is intentionally deferred

The fundamental physiologic problem is excessive left-to-right shunting and pulmonary overcirculation.

Before banding:

Large shunt → high Qp → high distal PAP → pulmonary congestion → ventricular volume overload

After appropriate banding:

Controlled Qp → lower distal PAP → reduced pulmonary venous return → improved ventricular loading and systemic perfusion

Systemic oxygen saturation usually remains relatively high in a biventricular circulation. A modest reduction in saturation may accompany effective restriction, but oxygen saturation should not be used as the sole determinant of adequacy [2].

8. Main PAB After Systemic Outflow or Arch Reconstruction

Main PAB may also be incorporated into selected staged strategies after reconstruction of severe systemic outflow obstruction, including interrupted aortic arch, when a large intracardiac communication continues to permit excessive pulmonary blood flow.

Relief of arch obstruction restores systemic outflow but may simultaneously expose the pulmonary circulation to substantial pressure and flow through an unrestricted VSD or other communication. PAB can then protect the pulmonary vascular bed and control ventricular volume loading until subsequent intracardiac repair.

This setting emphasizes why band adjustment must be lesion-specific. Systemic arterial pressure may change substantially following arch reconstruction, and a band that appeared appropriate before restoration of systemic outflow may produce a different pressure ratio afterward.

9. Main PAB in Single-Ventricle Physiology

In a single-ventricle circulation, the objective is fundamentally different from that in a biventricular circulation.

With unrestricted pulmonary blood flow, pulmonary and systemic circulations compete for the output of a common functional ventricle:

Excessive Qp → reduced effective Qs → pulmonary congestion + systemic hypoperfusion

A main PA band increases pulmonary resistance and redirects a greater proportion of ventricular output toward the systemic circulation.

The physiologic objective is therefore not maximal systemic oxygen saturation but an appropriate Qp:Qs balance.

Traditional guidance has suggested reducing distal pulmonary arterial pressure toward values compatible with later Fontan physiology, approximately 15 mmHg, although this should be individualized and interpreted according to patient age, anatomy, pulmonary vascular resistance, and the planned timing of cavopulmonary connection [1].

A lower systemic oxygen saturation after appropriate banding may therefore represent improved circulatory balance rather than deterioration.

10. Evidence for Tighter Banding in Single-Ventricle Patients

Recent multicenter observational data provide additional insight into band sizing in functional single-ventricle patients with unrestricted pulmonary blood flow. Horie and colleagues studied 46 patients undergoing PAB and adjusted the bands to achieve pulmonary arterial pressure <20 mmHg and Doppler velocity across the band ≥3 m/s [3].

Patients with an initial band circumference of:

≤ body weight (kg) + 17 mm

had a higher rate of bidirectional cavopulmonary connection by 6 months and a lower incidence of Fontan-associated liver disease at 10 years than patients with larger circumferences. Importantly, tighter banding was not associated with increased rates of Damus–Kaye–Stansel procedures or pulmonary artery plasty [3].

These findings should not be interpreted as establishing a universal new formula. The cohort was small and observational. Nevertheless, the study reinforces an important concept: in single-ventricle physiology, relatively effective early restriction of pulmonary blood flow may facilitate subsequent cavopulmonary physiology and potentially influence long-term Fontan outcomes.

11. Oxygen Saturation and Perfusion Monitoring

Pulse oximetry is useful during PAB adjustment but is an imperfect surrogate for pulmonary blood flow and systemic oxygen delivery [2].

This distinction is particularly important in single-ventricle physiology. A high arterial saturation can coexist with excessive Qp and inadequate systemic flow. Conversely, a controlled fall in saturation after band tightening may accompany improved systemic perfusion.

Accordingly, oxygen saturation should be interpreted together with:

• Systemic arterial pressure
• Distal pulmonary arterial pressure
• Ventricular function
• Acid-base status
• Lactate
• Urine output
• Near-infrared spectroscopy when available
• Overall clinical evidence of systemic perfusion

Recent experience with physiology-guided bilateral PAB similarly emphasizes integrated monitoring of oxygen saturation, Doppler velocities, systemic arterial pressure, and cerebral and somatic regional oxygenation rather than relying on an isolated anatomic measurement [4]. Although bilateral PAB represents a different operation, the underlying principle is applicable to main PAB: banding should be titrated to the circulation, not merely to the vessel diameter.

12. Recognizing Overbanding and Underbanding

Excessively tight PAB

Findings suggesting excessive restriction include:

• Marked or progressive desaturation
• Systemic hypotension
• Reduced systemic perfusion
• Ventricular dysfunction
• Bradycardia or significant arrhythmia
• Progressive metabolic acidosis
• Rising lactate
• Critically reduced pulmonary blood flow

If these changes occur during tightening, the band should be loosened rather than maintaining a predetermined circumference or gradient.

Inadequately restrictive PAB

Findings suggesting insufficient restriction include:

• Persistently high distal pulmonary arterial pressure
• Ongoing pulmonary congestion
• Continued ventricular volume loading
• Excessive pulmonary blood flow
• Poor systemic perfusion caused by pulmonary runoff
• Minimal effective Doppler or pressure gradient across the band

The band may require additional tightening provided ventricular function and systemic hemodynamics remain satisfactory.

13. Complications and Contemporary Outcomes

PAB remains a significant palliative operation rather than a benign temporizing procedure. In a contemporary Society of Thoracic Surgeons Congenital Heart Surgery Database analysis of 2,677 main PAB procedures performed between 2016 and 2019, operative mortality was approximately 8%, with substantial variation according to diagnosis and clinical context [5]. Particularly high mortality was observed when main PAB was performed after another major procedure during the same hospitalization.

Single-center experience may yield substantially better results in selected populations. In a 305-patient series, Dehaki and colleagues reported approximately 2% mortality, with pulmonary artery bifurcation stenosis in approximately 2% and pulmonary valve injury in 0.3% [6].

Other recognized complications include:

• Band migration
• Branch PA distortion
• Pulmonary valve distortion or injury
• Erosion into the PA wall
• Inadequate restriction requiring revision
• Excessive restriction
• Need for PA reconstruction at subsequent repair
• Progressive subaortic obstruction in susceptible anatomies

These complications reinforce the importance of careful initial placement, secure fixation, and longitudinal imaging.

14. Adjustable Pulmonary Artery Banding

One limitation of conventional PAB is that the ideal degree of restriction may change after surgery as pulmonary vascular resistance, ventilation, systemic vascular resistance, and patient growth evolve.

Adjustable banding systems were developed to permit progressive postoperative modification without repeat thoracotomy or sternotomy. Such systems can facilitate gradual optimization of pulmonary arterial pressure and ventricular loading and may decrease the need for surgical band revision [7,8].

However, available studies are relatively small and heterogeneous, and robust comparative evidence regarding long-term survival, reintervention, and late pulmonary artery outcomes remains limited. Adjustable systems therefore illustrate the value of dynamic physiologic titration, but they do not eliminate the need for careful patient selection and hemodynamic assessment.

15. Practical Surgical Principles

The major principles of main PAB can be summarized as follows:

1. Position the band at the mid-main PA.
2. Preserve adequate distance from the pulmonary valve and PA bifurcation.
3. Secure the band with fixation sutures to prevent migration.
4. Use body-weight–based formulas only as an initial sizing guide.
5. Tighten the band progressively rather than committing immediately to a calculated circumference.
6. For biventricular circulation, a distal PAP of approximately 30–50% of systemic pressure is a conventional reference.
7. For single-ventricle physiology, substantially lower distal PA pressure may be desirable to prepare for cavopulmonary circulation.
8. Interpret oxygen saturation together with pressure, ventricular function, and systemic perfusion.
9. Do not use band gradient, circumference, or SpO₂ as an isolated endpoint.
10. Continue surveillance because the physiologic severity of a fixed band changes with growth and evolving pulmonary vascular resistance.

The central principle is that main pulmonary artery banding is a physiologic operation performed by an anatomic technique. The optimal band is not defined by a universal formula or a single pressure gradient, but by its ability to protect the pulmonary vascular bed while preserving systemic cardiac output, ventricular function, and oxygen delivery appropriate for the intended biventricular or single-ventricle pathway.

References

[1] Sharma R. Pulmonary artery banding: Rationale and possible indications in the current era. Ann Pediatr Cardiol. 2012;5(1):40-43. doi:10.4103/0974-2069.93709.

[2] Durandy Y. Pulmonary artery banding is still a valuable option. Front Pediatr. 2013;1:17. doi:10.3389/fped.2013.00017.

[3] Horie S, Shikata F, Oka N, Okamura T, Kondo R, Matsunaga Y, Matsui K, Hataoka T, Kitamura T, Miyaji K. Association between initial pulmonary artery band circumference and early and late outcomes in single-ventricle patients. Ann Thorac Surg. 2026;121(3):624-632. doi:10.1016/j.athoracsur.2025.08.011.

[4] İrdem AK, Balık H, Kılıç Y, Dinç PS. Physiology-guided bilateral pulmonary artery banding in high-risk neonates: early hemodynamic and perfusion outcomes. Front Cardiovasc Med. 2026;13:1803385. doi:10.3389/fcvm.2026.1803385.

[5] Devlin PJ, Argo M, Habib RH, McCrindle BW, Jegatheeswaran A, Jacobs ML, Jacobs JP, Backer CL, Overman DM, Karamlou T. Contemporary applications and outcomes of pulmonary artery banding: an analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database. Ann Thorac Surg. 2024;117(1):128-135. doi:10.1016/j.athoracsur.2023.09.020.

[6] Gholampour Dehaki M, Sadeghpour Tabaee A, Azadi Ahmadabadi C, Alizadeh Ghavidel A, Omra G. Pulmonary artery banding in the current era: Is it still useful? Ann Pediatr Cardiol. 2012;5(1):36-39. doi:10.4103/0974-2069.93708.

[7] Corno AF. Pulmonary artery banding. Swiss Med Wkly. 2005;135(35-36):515-519. doi:10.4414/smw.2005.11081.

[8] Changizi A, Yaghoubi A, Azarasa M, Ghaffari S, Montazerghaem H. A study on the mortality and complication rates following percutaneously adjustable pulmonary artery banding. J Cardiovasc Thorac Res. 2014;6(4):253-255. doi:10.15171/jcvtr.2014.021.