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Palliative operations


Operations have been devised to improve hemodynamics and balance blood flow in complex congenital cardiac anomalies. These operations are performed in a staged manner, to allow intervention for complete repair at a later time when the patient’s age and size and the clinical situation are more conducive to a successful outcome.

Subclavian artery–pulmonary artery anastomosis

Prior to the landmark work of Alfred Blalock, MD, surgery for “blue” babies was not performed. The feasibility of anastomosis of a systemic artery to a pulmonary artery was demonstrated experimentally and carried to the operating room by Blalock and associates in 1944. The initial operation in a 15-month-old girl weighing 4 kg involved anastomosis of the left subclavian artery to the left pulmonary artery. The right innominate or subclavian artery was used for anastomosis in subsequent operations.

Figure 30-1, Blalock-Taussig Shunt A Right subclavian artery–right pulmonary artery anastomosis (Blalock-Taussig shunt). This specimen demonstrates a perfectly executed Blalock-Taussig shunt. The aorta enters the middle of the image from below. The three arch branches are demonstrated; the brachiocephalic or innominate artery is the first branch and is intact. The left carotid and left subclavian arteries have been divided. The hemostat is on the right carotid artery. The right subclavian artery has been divided after ligating its side branches with hemoclips. The right subclavian artery is turned down to the right pulmonary artery, where anastomosis has been performed with interrupted stitches of fine polypropylene. B A posterolateral thoracotomy incision is made on the side opposite the aortic arch. In most cases the incision is a right thoracotomy. The thorax is entered through the bed of the nonresected fourth rib. The mediastinal pleura is opened from the pulmonary artery parallel to the superior vena cava and over the right subclavian artery. The azygos vein is mobilized, ligated, and divided. The distal ligature on the doubly ligated superior vena cava side of the azygos vein may be used as a traction suture for the vena cava to retract it medially and anteriorly. The right pulmonary artery is completely mobilized, and double-loop tourniquet ligatures are placed on the apical anterior segmental branch and the pars intermedius of the pulmonary artery. The right pulmonary artery is mobilized as far medially as possible. The pericardium is dissected off the right pulmonary artery, preserving the integrity of the pericardial sac. C The right subclavian artery is identified and mobilized. Heparin 100 U/kg is administered intravenously to prevent fibrin formation within the subclavian artery during dissection. A rubber band or vessel loop is passed around the right subclavian artery for atraumatic retraction. The branches in the subclavian artery are ligated and divided. The vagus nerve is identified. A small right-angled clamp is passed beneath the vagus nerve, and the anterior surface of the subclavian artery is mobilized from beneath the nerve. The subclavian artery is ligated. A Cooley vascular clamp is passed beneath the vagus nerve and used to occlude the subclavian artery distally at the ligature. The subclavian artery is divided, and the Cooley clamp is withdrawn from beneath the vagus nerve to remove the subclavian artery from the loop formed by the vagus nerve and its recurrent branch. D With the Cooley clamp on the distal end of the subclavian artery for retraction, the carotid and innominate arteries are completely mobilized from the connective tissue of the mediastinum. Dissection should be taken as far as possible on the carotid artery and as far medially on the innominate artery as possible to obtain maximal mobilization and length of the subclavian artery for approximation to the right pulmonary artery. E A Dietrich vascular clamp is placed on the subclavian artery at its takeoff from the innominate artery. A Blalock vascular clamp is placed across the right pulmonary artery, and tourniquet ligatures on the distal branches of the right pulmonary artery are secured. Using a No. 11 scalpel, an incision is made halfway across the subclavian artery proximal to the occlusion clamp, preserving the appropriate length to reach the right pulmonary artery incision; at the same time, the incision is made as far proximal in the subclavian artery as possible to obtain maximal diameter. F A longitudinal incision is made in the anterior and superior aspects of the right pulmonary artery. The length of the incision should approximate the diameter of the subclavian artery, recognizing that the pulmonary artery incision always enlarges during the course of the anastomosis. G Continuous stitches of 7/0 polypropylene are used to construct a back row in the anastomosis. All the suture loops are placed for this back row before the arteries are approximated. The needle is passed from the lumen or intimal surface out of the subclavian artery and then passed from the adventitial surface of the pulmonary artery into its lumen. The end of the subclavian artery is excised, and an appropriate bevel is fashioned. This step must be performed carefully to preserve length on the anterior surface of the subclavian artery. H The suture loops are then pulled up to approximate the subclavian artery to the pulmonary artery. I The front row of the anastomosis is completed using interrupted stitches. Two stitches are placed initially at each end of the anastomosis to secure the continuous stitch. All interrupted stitches of the front row are placed before any are tied; this ensures the accuracy of the anastomosis and prevents picking up the back row of the anastomosis. Laks-Castaneda Modification J When it is necessary to use the subclavian artery on the same side as the aortic arch, the Laks-Castaneda subclavian aortoplasty may be used to prevent kinking of the subclavian artery over the aortic arch. After complete mobilization of the subclavian artery and the distal portion of the aortic arch, the subclavian artery is ligated and divided. A partial-occlusion vascular clamp is placed on the distal aortic arch to exclude the base of the subclavian artery. An incision is made in the base of the subclavian artery, extending distally on the artery and into the aortic arch, opposite the base of the artery. This longitudinal incision is closed in a transverse fashion using fine polypropylene suture in continuous stitches. This suture line transplants the subclavian orifice onto the anterior wall of the aortic arch so that the subclavian artery is directed toward the pulmonary artery without distortion or kinking. K The anastomosis of the distal end of the subclavian artery to the pulmonary artery is constructed by partial exclusion of the pulmonary artery using a technique similar to that described for the standard Blalock-Taussig shunt. Modified Blalock-Taussig Shunt L A modification of the Blalock-Taussig shunt principle, in which a prosthetic graft is interposed between the subclavian and pulmonary arteries, combines simplicity of performance, favorable blood flow characteristics controlled by the size of the subclavian artery, lack of distortion of the pulmonary artery, and preservation of subclavian artery blood flow. The operation may not be perfect for long-term palliation, but it is satisfactory when palliation for less than 2 years is required. The shunt is performed on the same side as the aortic arch, in most instances through a posterolateral thoracotomy. For patients with the usual left arch anatomy, the left subclavian artery and the proximal portion of the left pulmonary artery are mobilized. A small, curved vascular clamp is used to isolate the left subclavian artery just distal to its origin. A 4- or 5-mm polytetrafluoroethylene (PTFE) graft is beveled to fit the side of the subclavian artery and is directed toward the proximal pulmonary artery. An end-to-side anastomosis of the graft to the subclavian artery is constructed by continuous stitches with 6/0 or 7/0 polypropylene. M The vascular clamp is used to isolate a portion of the left pulmonary artery. The graft is then beveled appropriately to approximate the pulmonary artery. An end-to-side anastomosis of the graft to the pulmonary artery is constructed by continuous stitches using fine polypropylene suture.

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