Decision Making In the patient with duct-dependent pulmonary blood flow, creation of a reliable source of flow is generally performed within the first week of life Classically a thoracotomy is performed on the side opposite arch dominance and an ePTFE graft is used to create a shunt between the innominate artery and the ipsilateral proximal pulmonary artery This approach results in a primary median sternotomy incision for the next-stage operation, but the disadvantage is that the duct cannot be controlled or ligated at the completion of the procedure Having both a patent arterial duct and a systemic-to-pulmonary artery shunt results in hypotension and low-velocity flow through the synthetic shunt, which predisposes to shunt thrombosis; however, this does not become apparent until the duct begins to close In the current era a median sternotomy incision is commonly used for shunt construction There are several advantages to a median sternotomy.73 The duct can be ligated after construction of the shunt and the adequacy of the shunt can therefore be determined The innominate artery and the proximal branch pulmonary artery are more easily accessed If necessary, cardiopulmonary bypass support can be used for construction of the shunt if the patient does not tolerate branch pulmonary artery occlusion Patch arterioplasty is necessary for proximal branch pulmonary artery stenosis in the region of duct insertion Surgical Technique Thoracotomy: The patient is placed in the lateral decubitus position and a posterolateral thoracotomy incision is made on the side opposite the aortic arch through the fourth interspace An incision is made in the mediastinal pleura posterior to the superior caval vein, and the pulmonary and innominate arteries are identified Lymph nodes along the side of the trachea are resected and the pulmonary artery is dissected as far medially as possible The innominate artery is fully mobilized Heparin is administered, typically, 100 units/kg, and the innominate artery is isolated A longitudinal incision is made in the inferior surface of the innominate artery A 3.5- or 4.0-mm graft is commonly used The graft is cut in a beveled fashion to accommodate the angle of the innominate artery and an anastomosis is constructed with fine monofilament suture An alternative approach is to perform the proximal anastomosis to the subclavian artery The use of the smaller subclavian artery as the origin of the shunt will add resistance to shunt and allows for larger-caliber graft to be used; it may also be useful in the smaller patient to accommodate a normal-caliber graft.65 Once the proximal anastomosis is complete, the graft is cut to the appropriate length to reach the pulmonary artery The innominate artery is de-aired, flow is restored, and the graft is controlled with a fine vascular clamp After isolating the pulmonary artery, a longitudinal arteriotomy is made in the pulmonary artery and the distal anastomosis is performed Clamps and snares are removed from the pulmonary artery and the shunt is opened There should be a drop in blood pressure corresponding to flow in the shunt with an increase in pulmonary artery saturations Prostaglandin infusion is halted Sternotomy: The patient is placed in the supine position and a median sternotomy incision is performed After exposing the heart, the innominate artery is mobilized The proximal ipsilateral pulmonary artery is likewise exposed It may be possible to encircle the duct at this point, but care should be taken, as this may not be tolerated because it can result in excessive hypoxemia; in addition, the duct can be bruised or injured, and this would also compromise pulmonary blood flow The shunt is constructed the same as for a thoracotomy approach Following completion of the shunt and after it has been opened, the duct can be encircled and snared to make certain that there will be adequate pulmonary blood flow with the newly constructed shunt If the saturations remain satisfactory, the duct is ligated If the patient develops excessive hypoxemia with snaring of the duct, a stepwise approach to determine the problem should be undertaken, including making certain that ventilation is adequate The shunt should finally be inspected for technical issues Revision of the shunt or replacement with larger graft should be considered if occlusion of the duct is not tolerated Unobstructed Systemic and Pulmonary Blood Flow With initiation of spontaneous respiration after birth, PVR begins to drop For patients with a fUVH and without anatomic limitation to pulmonary or systemic blood flow, heart failure will predictably develop with the drop in PVR Decision Making Pulmonary artery banding is the first stage of palliation in neonates with unrestrictive pulmonary blood flow and no systemic outflow tract obstruction (Fig 71.3).74 Pulmonary artery banding relieves the volume load on the heart; otherwise heart failure may ensue Pulmonary artery banding reduces pulmonary artery pressure, allowing for continued remodeling of the pulmonary vascular bed for subsequent second stage of palliation Neonatal PVR reaches a nadir around the third or fourth week of life, and traditionally pulmonary artery band placement has been performed after 2 or 3 weeks of age It has been thought that placing a pulmonary artery band in the early neonatal period may lead to the need to reoperate for band readjustment once the PVR falls.75 Recent data, however, suggest that delay is not necessary, and that pulmonary artery banding can be performed during the first week or two of life.76 FIG 71.3 Construction of a pulmonary artery band (PAB) Ao, Aorta; PA, pulmonary artery (From Tweddell JS Principles and practice of pediatric surgery In: Oldham KT, Colombani PM, Foglia RP, et al, eds Annals of Surgery Philadelphia: Lippincott Williams & Wilkins; 2006:1804.) Ligation of the main pulmonary artery and placement of a systemic-topulmonary artery shunt has been advocated by some as a strategy to manage the patient with unrestricted pulmonary blood flow The theoretical advantage is the ability to more precisely control pulmonary blood flow This is uncommonly used in practice due the increased risk of systemic-to-pulmonary artery shunt compared with pulmonary artery banding Pulmonary artery banding can be performed through a thoracotomy or median sternotomy incision If the arterial duct is patent or there is any question of ... Construction of a pulmonary artery band (PAB) Ao, Aorta; PA, pulmonary artery (From Tweddell JS Principles and practice of pediatric surgery In: Oldham KT, Colombani PM, Foglia RP, et al, eds Annals of Surgery Philadelphia: Lippincott Williams & Wilkins; 2006:1804.)