Pulmonary artery banding (PAB) is a palliative surgical technique used to rectify congenital cardiac defects by restricting blood flow to the pulmonary artery.
Some facts about Pulmonary Artery Banding:
- Pulmonary artery banding is usually performed in small infants with congenital heart disease who have excessive pulmonary blood flow.
- Pulmonary artery banding is also performed for patients with single ventricular anatomy in whom corrective surgery is not possible until later in life.
- Patients with multiple VSDs in whom complete repair can be more safely performed at a later age can also under go this surgery.
- A pulmonary artery band usually placed which allows for better growth and development of infants.
- Pulmonary vasculature can be protected by reducing excessive pulmonary blood flow, thereby preventing the onset of irreversible remodeling of the pulmonary vasculature and pulmonary hypertension.
- The surgery is done for infants born with cardiac defects characterized by left-to-right shunting and pulmonary over-circulation .
- A condition of irreversible pulmonary hypertension can be developed due to parietal hypertrophy of the pulmonary arterioles.
- Fatigue, tachypnea, dyspnea and failure to thrive due to the volume overload of the LV or 'single ventricle' are the symptoms of this congenital heart defects.
Preparation for Pulmonary Artery Banding:
- Many hemodynamic and respiratory variables like systemic and pulmonary resistances, heart rate, type of congenital heart defect, heart contractility and mechanical ventilation can influence the effects of banding on pulmonary pressure..
- The type of cardiac defect, the foreseen resolution of the main congenital defect in the setting of a staged approach, the type of intracardiac shunt, and the experience of the team should be taken in to account in a patient who is considered for PAB.
Procedure for Pulmonary Artery Banding:
- The surgical technique of PAB consists of resizing the pulmonary artery or its branches by placing a band around the vessels.
- However, there is difficulty in finding out the optimal point of constriction of the pulmonary artery, since minimal changes to the pulmonary diameter have a major effect on resistance and flow.
- Pulmonary artery banding can be performed through median sternotomy or left thoracotomy.
- Cardiopulmonary bypass is not required for this surgical technique.
- A catheter will be placed in the distal main pulmonary artery for pressure monitoring and a band will be placed around the main pulmonary artery and sutured into place
- The band is then tightened with the help of successive sutures until the pulmonary artery
- Pressure usually falls to 30 to 50 percent that of systemic pressure.
- The pulmonary artery band is too restrictive and causes right to left shunting of blood if there is a significant drop in arterial oxygen saturation.
- Peripheral arterial oxygen saturation should not drop severely.
- Also, there should not be a rise in right ventricular pressure to supra-systemic level.
- The diameter of the main pulmonary artery can be reduced, there by decreasing blood flow to the pulmonary branches and reducing pulmonary artery pressure with PAB.
- Concomitant improvement of systemic pressure, ventricular function and cardiac output can be expected in patients with a large left-to-right shunt.
- Pulmonary branch distortion or a supravalvular pulmonary stenosis is one of the most recurrent problems of PAB that needs to be addressed at the time of corrective surgery.
- It is impossible to avoid the use of cardiopulmonary bypass for pulmonary reconstruction in cases of compulsory debanding.