Care is taken to adjust the left ventricular ventto maximize drainage and maintain a bloodless field for the neoaortic reconstruction. Figure 9.7 shows the already dissected right coronary artery (forceps) and scissor dissection of the left main coronary artery. The dotted lines on the pulmonary artery, soon to become the neoaorta, represent the excisions (approximately two thirds of the estimated area of the coronary buttons) that are performed to transfer the coronary artery buttons to the respective sinus of Valsalva to complete the proximal neoaortic reconstruction. Figure 9.8 demonstrates the electrocautery mobilization technique (using a very low setting) that avoids tension or kinking at the coronary anastomosis. The localized pulmonary artery at the sinus of Valsalva is resected in Fig. 9.9 to prepare the coronary transfer. Figure 9.10 shows the left main coronary button anastomosis being commenced at the center point of the coronary button and the sinus of Valsalva. Some surgeons prefer to rotate the coronary button to achieve a “best lie” configuration. It is left to the operating surgeon to decide on the best anatomic arrangement to optimize flow after reconstruction. The suture line is usually commenced with 8-0 running monofilament suture on one side (Fig. 9.11) and then the other (Fig. 9.12). Individual sutures at the top of the anastomosis are used to anchor the running suture. The surgeon should be able to differentiate which suture represents the running suture that was used for the anastomosis and which one represents the anchoring suture that was placed at the top of the anastomosis. In this way, the surgeon will know whether to redo the entire anastomosis if one of the sutures snaps during the tie. If the anchoring suture snaps, then the other one can be used to anchor the suture line, but if the running suture snaps, then the entire anastomosis may need to be redone to avoid unraveling. Figure 9.13 shows the right coronary sinus being prepared for coronary transfer by local wall resection. The same suturing technique is applied to this sinus (Fig. 9.14). Figures 9.15 through 9.17 show the staged progression of the maneuver of Lecompte. The pulmonary artery is brought anterior to the ascending aorta (Fig. 9.15), and the forceps temporarily occlude the aorta immediately posterior to the newly positioned ascending aorta (Fig. 9.16). The aortic cross clamp is now released (because the ascending aorta is controlled by the forceps) and is placed on the ascending aorta inferior and posterior to the ascending aorta (Fig. 9.17). This maneuver assures the position of the pulmonary artery in front of the neoaorta during the completion of the neoaortic anastomosis. The neoaortic anastomosis is commenced (Fig. 9.18) at the posterior position, making sure that the two structures align accurately. Failure to achieve accurate alignment results in a poor reconstruction, which can cause coronary artery kinking and neoaortic regurgitation owing to anastomotic malrotation and mismatch. The neoaortic anastomosis is usually performed with running suture technique, but occasionally the surgeon recognizes poor apposition of the suture line, especially in the area of the coronary artery button-anchoring stitch. An interrupted suture in this location (Fig. 9.19) ensures hemostasis and is well worth the effort. The rest of the anastomosis is performed with these tenets in mind (Fig. 9.20), and the de-airing maneuvers are performed in tandem with release of the cross clamp before the final tie is performed (Fig. 9.21).
The patient can now be rewarmed during the neopulmonary artery reconstruction. Figure 9.22 shows the proximal aorta, soon to become the neopulmonary artery, with the dissected sinuses of Valsalva. A rectangular piece of pericardium is incised centrally to construct a pantaloon patch; when sutured appropriately, this patch fills the dissected sinuses of Valsalva. The suture is placed at the apex of the incised pericardium and approximated to the apex of the posterior commissure. Running suture technique (7-0 monofilament suture) is used for this reconstruction. Figure 9.23 shows the anastomosis in progress, with a sucker in the orifice of the neopulmonary artery to facilitate exposure. Once it is finished, the very important tapering of the pericardial patch is performed. There are two principles to this technique. First, the posterior portion of the pericardial patch is intentionally left approximately 3–4 mm longer to decrease any chances of coronary artery compression from the neopulmonary artery. This extra distance allows a favorable match between the neopulmonary artery and the distal pulmonary artery, without posterior compression of the coronary arteries (Fig. 9.24). Second, the patch is cut in a semicircular, crescent-shaped configuration, not in a straight line from commissure to commissure. This maneuver ensures redundant neo-sinuses of Valsalva (Fig. 9.25), mitigating against the development of supravalvar PS, which was the most common complication of ASO prior to the institution of this redundant pantaloon pericardial patch. Figure 9.26 shows the completed repair after separation from cardiopulmonary bypass and decannulation.
9.3 Arterial Switch with Interrupted Aortic Arch
The principles of aortic arch repair are similar to the repair of any other cardiac malformation with interrupted aortic arch. In general, the ascending aorta in patients with transposition, VSD, and interrupted aortic arch or coarctation is very small and requires enlargement for the neoaortic reconstruction after the arch repair. The arch repair therefore requires complete ductus arteriosus removal, posterior suture reconstruction, and anterior patch augmentation that brings the patch into the transverse arch and the ascending aorta. This allows for an enlarged outflow tract reconstruction and a more favorable anastomosis with the proximal neoaortic reconstruction. Cardiopulmonary bypass techniques (dual arterial cannulation, regional perfusion, deep hypothermia, and circulatory arrest), cardioplegia administration, and suturing strategies guides the surgeon in completing this very challenging operation.
Anticipated reparative operations for these patients later in life centers around acquired or residual arch obstruction, supravalvar neopulmonary stenosis, and coronary artery problems. Careful evaluation and cautious planning directs the surgeon toward successful resolution of these problems.
9.4 Coronary Artery Anomalies
Coronary artery anomalies are quite frequent in patients with TGA and can include every imaginable configuration. The Leiden classification has simplified the nomenclature by naming sinuses 1 and 2 and is characterized by imagining a surgeon standing in the non-coronary cusp of the aorta looking posteriorly. The surgeon’s right hand signifies Sinus 1 and the left hand signifies Sinus 2. In this manner, all types of configurations can be noted by simply describing which coronaries arise from each of the sinuses. This classification can account for inverted coronary arteries, single coronary arteries, and intramural coronary arteries by simple description. In general, the principles of management require careful intraoperative diagnosis, establishing appropriate cardioplegic techniques (consistent with the anticipated longer cross-clamp time), which may involve retrograde cardioplegia or intracoronary administration, and extensive mobilization of the coronary artery buttons for eventual transfer. Small pericardial patches may also be necessary, especially for single coronary artery buttons, which cannot be transferred easily. Figure 9.27 shows a Sinus 1–no coronary artery and Sinus 2–left anterior descending, circumflex, right coronary artery origins. In addition, the left main coronary artery has an intramural route that courses across the commissure into Sinus 1, where it emerges as the left main coronary artery. This is a very challenging artery to reconstruct. Figure 9.28 shows the surgeon’s diagrammatic view of the coronary artery anatomy—the reverse of the anatomist’s convention, which views the anatomy from the feet up. The surgeon views the anatomy from the head down. From the outset and before any incisions are made, the surgeon must decide whether there is enough room between the orifices of the two coronary arteries to form two distinct buttons. Usually, two buttons can be formed. Figure 9.29 shows the right coronary artery button being mobilized after it has been detached from the common aortic wall and the other coronary artery. The mobilization of this coronary button is less complex than mobilization of the left main coronary button. The remaining coronary button must be separated from the aortic wall and the posterior commissure where the leaflets are attached, using sharp dissection and mobilizing the commissural attachment with a portion of the aortic wall to allow for eventual reconstruction (Fig. 9.30). The intramural segment is then unroofed and tacking sutures are placed at the neo-orifice to insure the integrity of the orifice and to avoid dissection and occlusion (Fig. 9.31). The artery is then mobilized with careful, low-setting electrocautery techniques (Fig. 9.32). The surgeon must decide whether to unroof the intramural course. (In this set of drawings, the intramural course of the coronary artery is unroofed.) In the developmental stages of the arterial switch procedure, unroofing was not always performed owing to fear of coronary disruption and dissection, but current wisdom is to always unroof the course of the intramural artery to avoid any future problems. (This issue will be revisited later in this chapter.). Figure 9.33 depicts the coronary artery buttons being implanted to the ascending neoaorta using techniques previously noted in this chapter. The reconstructed proximal neoaorta is shown in Fig. 9.34. Often, the proximal neoaortic reconstruction is much larger than the distal aorta, especially when the coronary buttons are anomalous and require more space for reimplantation. Under these circumstances, the ascending aorta can be enlarged by linear incision and pericardial patch augmentation (Fig. 9.35) to allow a more appropriate anastomotic alignment that avoids coronary artery restriction and neoaortic valve infringement.
The neopulmonary artery reconstruction is commenced with the pericardial patch, which in this case is not cut into a pantaloon configuration because the coronary artery detachment involved much of the posterior pulmonary artery wall. The pericardium is therefore sewn to the edges of the remaining neopulmonary artery wall in anticipation of commissural reattachment to the implanted pericardium (Fig. 9.35). Once the pericardium is sewn in place, the posterior commissure can be reattached to the pericardial wall with interrupted suture technique (Figs. 9.36 and 9.37). This reattachment can be followed by end-to-end anastomosis between the reconstructed proximal neopulmonary artery and the distal pulmonary artery.
Some single coronary artery anomalies are not amenable to division and individual reimplantation to the neoaorta, owing to the close proximity of the coronary artery origins. Such is the case with a single coronary artery origin from Sinus 2, as seen in Fig. 9.38. The dotted lines depict the area of dissection and separation from the aorta and the area of reimplantation into the pulmonary artery, soon to become theneoaorta. To re-implant the coronary artery button directly into the neoaorta without any patches, the coronary button would have to be rotated 180°, which would cause a complete obstruction owing to kinking. An acceptable alternative to this situation is to mobilize the branches of both coronary arteries and rotate the coronary artery button 90° (Fig. 9.39) by suturing the superior edge of the coronary artery button to the inferior portion of the incised sinus of Valsalva (Fig. 9.40). A piece of pericardium can then be used to create a hood, thereby ensuring a patent and unobstructed pathway to the coronary arteries (Figs. 9.41, 9.42, and 9.43). Other coronary artery configurations may require more creative solutions. The principles are the same, however: They require close attention to myocardial preservation, coronary mobilization, and tension-free anastomoses, which enhances flow.