The Arterial Switch Procedure: Closed Coronary Artery Transfer Edward L

The Arterial Switch Procedure: Closed Coronary Artery Transfer Edward L. Bove, MD

he arterial switch operation has been the accepted pro- coronary artery arises from the right coronary and passes Tcedure for the repair of transposition of the great arteries posterior to the pulmonary artery root, is seen in approxi- (TGA) with or without associated defects for over 2 decades. mately two-thirds of all patients with d-TGA. With increasing Many of the technical intricacies have been developed and operative experience, a variety of coronary artery patterns modiﬁed over these years such that this procedure is now were encountered by the surgeon, some rarely, and the tech- associated with very low risk even in the neonate with com- niques were altered to deal with these anomalies. Both early plex forms of TGA.1,2 From the earliest experience, the sur- and late follow-up reports emphasized the importance of gical techniques involved for the transfer of the coronary proper coronary artery alignment, the avoidance of tension arteries have received the most scrutiny. In the most common on the anastomoses, and the need to develop a reliable, re- coronary artery pattern, the right coronary artery arises from producible technique to deal with even subtle coronary ar- the right aortic sinus of Valsalva and the left main coronary tery anatomic variations. At the University of Michigan CS artery from the left aortic sinus (Fig 1). This pattern, in addi- Mott Children’s Hospital, the technique of transferring the tion to the most common variant in which the circumﬂex coronary artery buttons after reconstruction of the neo-aorta has been utilized since the beginning of our experience in the mid 1980s.3 This approach was used in an effort to minimize Section of Cardiac Surgery, Division of Pediatric Cardiac Surgery, The Uni- any “guesswork” in the transfer of the coronary artery buttons versity of Michigan Medical School, Ann Arbor, Michigan. Address reprint requests to Edward L. Bove, MD, 5144 Cardiovascular Cen- and to provide a safe, reliable technique easily taught to train- ter, 1500 East Medical Center Drive, Ann Arbor, MI 48109. E-mail: ees and fellows. The details of this technique of closed coro- [email protected] nary artery transfer are described in this review.

Operative Technique The transfer of the coronary artery buttons during an arterial switch operation for TGA should accomplish a number of things. First, it should be safe and reliable in all anatomic conditions, avoiding the potential to have tension or distor- tion on either of the anastomoses, problems which may not become apparent until the patient is weaned from cardiopul- monary bypass. Although less accepted, it may also be opti- mal to preserve the sinotubular junction to reduce the risk of late aortic valve regurgitation. The technique of closed coronary artery transfer is based on the knowledge that once the neo-aorta is reconstructed and the aortic clamp removed to distend the aortic root, the location for each coronary button can be precisely determined with the least amount of dissection of the coronary arteries themselves. The procedure is done utilizing continuous cardiopulmo- Figure 1 The typical coronary artery pattern seen in d-TGA as nary bypass with moderate hypothermia and intermittent viewed from the superior aspect (surgeon’s view). Note the symmet- cold blood cardioplegia. The latter is begun antegrade with rical orientation of the aortic and pulmonary valve commissures. subsequent doses delivered retrograde through the coronary LAD ϭ left anterior descending coronary artery; LCX ϭ left circum- sinus. Wide mobilization of the branch pulmonary arteries is flex coronary artery; RCA ϭ right coronary artery. accomplished in the usual fashion after division of the ductus arteriosus. Atrial and ventricular septal defects are closed artery dissection is needed and any dissection is done well first, following which the ascending aorta is divided at a point away from the coronary artery itself to avoid damage to the corresponding to a level that is at least 5 to 7 mm distal to the vasa vasorum. After the aortic cross-clamp is removed and bifurcation of the pulmonary arteries (Fig 2A). It is important the neo-aorta is distended closing the valve, an incision is to leave a long proximal ascending aorta (neo-pulmonary made at the precise point where each coronary button lies artery) to facilitate subsequent coronary transfer and an op- against the aorta free of tension (Fig 5A). This incision is timal position of the anteriorly relocated branch pulmonary placed in an oblique fashion to align the coronary artery in a arteries. The main pulmonary artery is divided at its bifurca- more natural orientation without twisting (Fig 5B and C). tion and the relative positions of the commissures of both The very superior extent of the incision may be angled me- semi-lunar valves are noted (Fig 2B). A marking suture is dially to form a trapdoor if additional tissue is necessary to placed exteriorly at the top of each neo-aortic commissure; a complete the anastomosis. Only as much mobilization of the Lecompte maneuver is performed, and the distal ascending coronary as is needed to allow this anastomosis to be done aorta is anastomosed to the proximal main pulmonary artery with no tension is performed, and often no mobilization at all (Fig 2B and C). The geometry of the neo-aortic root is well is required. The left coronary artery anastomosis is com- preserved, allowing the coronary artery buttons to be placed pleted first, followed by the right, which is accomplished without dividing the sinotubular junction (Fig 3). Each cor- using the same principles (Fig 5D). The reconstruction of the onary artery button is excised from the aortic root, taking a neo-pulmonary root with a pantaloon-shaped patch of autol- wide rim of adjacent aortic tissue (Fig 4). Very little coronary ogous pericardium is then performed (Fig 6A and B).4,5 The arterial switch procedure 311

Figure 2 The aorta is divided 5 to 7 mm distal to the level of the pulmonary artery bifurcation and the precise locations of the coronary artery ostia and valve commissures are noted (A). A LeCompte maneuver is performed (B, C). Ao. ϭ aorta; LPA ϭ left pulmonary artery; MPA ϭ main pulmonary artery; RPA ϭ right pulmonary artery. 312 E.L. Bove

Figure 3 After marking the precise locations of the superior extent of each neo-aortic valve commissure with an external suture, the neo-aorta is reconstructed and the clamp removed. Ao ϭ aorta; MPA ϭ main pulmonary artery. The arterial switch procedure 313

Figure 4 The coronary artery buttons are removed with as wide a rim of aortic tissue as possible. Dissection of the branches is avoided or minimized until the extent of mobilization needed for a tension-free anastomosis is determined. Ao ϭ aorta. 314 E.L. Bove

Figure 5 After removing the cross-clamp, distending the root, and closing the neo-aortic valve, the incision for the left coronary button is made within the facing sinus of Valsalva (A). The oblique orientation helps in achieving the proper orientation of the coronary artery (B, C), avoiding kinking of the vessel. The right coronary artery button is transferred using the same technique (D). Ao. ϭ aorta; MPA ϭ main pulmonary artery. The arterial switch procedure 315

Figure 6 The neo-pulmonary artery is reconstructed using a pantaloon-shaped patch of autologous pericardium. 316 E.L. Bove

Limitations identify the location of the neo-aortic valve commissures has proved to be safe, avoiding injury to the valve when the This approach for coronary artery transfer is applicable for incision in the sinus of Valsalva is made. nearly all types of coronary artery patterns. However, when the great vessels are oriented in a side-by-side position, transfer of the posterior coronary artery after the neo-aorta is re- References constructed may be more difﬁcult. In this situation, a more 1. Bove EL, Byrum CJ, Sondheimer HM, et al: Arterial repair for simple and typical open anastomosis is often performed. complex forms of transposition of the great arteries. J Cardiovasc Surg 28:54-60, 1987 2. Bove EL, Beekman RH, Snider AR, et al: Arterial repair for transposition Conclusions and large ventricular septal defect in early infancy. Circulation 78:III-26- III-31, 1988 (suppl III) Closed coronary artery transfer during the arterial switch 3. Bove EL: Current technique of the arterial switch procedure for transpo- operation for transposition of the great arteries is a reliable sition of the great arteries. J Cardiac Surg 4(3):193-199, 1989 and safe method that facilitates precise transfer of the coro- 4. Lupinetti FM, Bove EL, Snider AR, et al: Intermediate-term survival and nary buttons into the neo-aortic root. This technique mini- functional results after arterial repair for transposition of the great arteries. J Thorac Cardiovasc Surg 103:421-427, 1992 mizes the risk of tension on the anastomosis, facilitates 5. Qamar ZA, Goldberg CS, Devaney EJ, et al: Current risk factors and proper alignment, and can be done with minimal coronary outcomes for the arterial switch operation. Ann Thorac Surg 84:871- artery mobilization. The use of external marking sutures to 879, 2007