Transposition of the Great Arteries and Intact Ventricular Septum: Anatomical Repair in the Neonate Aldo R. Castaneda, M.D., William I. Norwood, M.D., Richard A. Jonas, M.D., Steve D. Colon, M.D., Stephen P. Sanders, M.D., and Peter Lang, M.D. ABSTRACT Fourteen neonates 18 hours to 32 days old differently from the left when challenged with increased with transposition of the great arteries (TGA) and virtually afterload by the infusion of methoxamine hydrochloride intact ventricular septum (IVS) underwent arterial switch [l]. Also, atrial dysrhythmias related to dysfunction of operations under deep hypothennic circulatory arrest. the sinus and atrioventricular nodes are associated with Preoperative left ventricular to right ventricular peak sys- serious morbidity and mortality in a significant number tolic pressure ratios ranged from 0.7 to 1.0 (mean, 0.92), of patients who have undergone atrial inversion repair of TGA. and the echocardiogram showed a centrally positioned Jatene’s successful arterial switch operation in 1975 ventricular septum in 10 patients and a rightward dis- resulted in a renewed and increasing interest in anatom- placed ventricular septum in 4. One patient died twelve ical repair of TGA [2]. Jatene recognized early in his hours after operation. Postoperative complications in- experience that a left ventricle that has developed for cluded bleeding from the left coronary artery-pulmonary some time in the low-resistqnce pulmonary circuit may artery anastomosis (1 patient), stenosis of the pulmonary fail acutely following an arterial switch operation. Con- artery-aorta anastomosis requiring reoperation (2 pa- sequently, he recommended the operation principally tients), transient ST segment and T wave abnormalities for patients with TGA and a ventricular septa1 defect consistent with ischemia (3), and development of patho- (VSD) or a large patent ductus arteriosus (PDA). Since logical Q waves suggestive of clinically silent infarction TGA most often is not associated with either of these anomalies, for anatomical repair to have wide applica- (2). tion in the management of TGA, a more comprehensive The capacity of the left ventricle in a neonate to effec- selection process is necessary. Yacoub and associates [3] tively take over the systemic circulation was clearly dem- have investigated the concept of preparing the left ven- onstrated. A longer follow-up period is needed to assess tricle for systemic pressure work in patients with TGA late ventricular function, coronary ostial growth, growth of and intact ventricular septum (IVS) by preliminary band- the aorta-pulmonary artery anastomosis, late aortic valve ing of the pulmonary artery followed later by debanding (anatomical pulmonary valve) function before definitive and an arterial switch operation. Alternatively, it can be recommendations about the superiority of the arterial reasoned that the left ventricle of the newborn should be switch operation in neonates with TGA plus IVS can be well suited for systemic function, as it has supported formulated. systemic pressure during gestation. This report constitutes our initial experience with the arterial switch operation in neonates with TGA and IVS. Intraatrial repair by the Senning or Mustard technique has dramatically enhanced the prospects for survival of Material and Methods children with transposition of the great arteries (TGA). From May, 1983, through December 1,1983,14 consecu- Over the years, the operative mortality and the inci- tive neonates with TGA {S,D,D} and IVS underwent an dence of many late complications of these operations arterial switch operation. There were 9 boys and 5 girls. have decreased significantly. Supported by the observa- They ranged in age from 18 hours to 32 days (mean age, tion that right ventricular (RV) failure or tricuspid regur- 6.6 days) and in weight from 1.8 to 4.4 kg (mean weight, gitation develops late in some patients after atrial inver- 3.4 kg). Ten of these neonates (71.4%)underwent the sion repair, an impression exists that the right ventricle arterial switch operation during the first week of life. is somehow inherently different from the left and may Ratios of RV to left ventricular (LV) pressure ranged not be well suited to support the systemic circulation from 0.7 to 1.0 (mean, 0.92) (Table). Associated car- indefinitely. Indeed, there is suggestive evidence that diovascular lesions included PDA (10 patients), a small the right ventricle in the systemic circulation responds VSD (2), coarctation of the aorta (l),and left juxtaposi- tion of the atrial appendages and dextrocardia (1). Before the arterial switch operation, 8 patients had a From the Departments of Cardiac Surgery and Pediahic Cardiology, Children’s Hospital Medical Center, and the Departments of Surgery balloon atrial septostomy, 9 received prostaglandin El, and Pediatrics, Harvard Medical School, Boston, MA. and 1 had resection of coarctation of the aorta. The Presented at the Twentieth Annual Meeting of The Society of Thoracic preoperative electrocardiogram demonstrated right-axis Surgeons, San Antonio, TX, Jan 23-25, 1984. deviation and pure R wave in V1 in 12 and an R waveIS Address reprint requests to Lk. Castanecla, Children’s Hospital Medical wave ratio of less than 1 in V6 in 9 neonates. Center, 300 Longwood Ave, Boston, MA 02115. All patients underwent preoperative echocardio- 438 439 Castaneda et al: TGA and Intact Ventricular Septum in Neonate Preoperative Left Ventricular and Right Ventricular Peak Systolic Pressures and Pressure Ratios Age at LV RV LV/RV Operation Pressure Pressure Pressure (day) (mm Hg) (mm Hg) Ratio 1 50 52 0.9 2 52 55 0.9 2 48 48 1.0 2 70 70 1.0 2 65 68 0.9 2 70 70 1.0 2 50 52 0.9 4 75 75 1.0 5 60 62 0.9 7 70 95 0.7 Fig 1. Sites of implantation of the left and right corona arteries on 10 60 78 0.7 y the pulmonary artery are marked by reference stitches. 10 62 62 1.0 14 58 67 0.8 32 82 92 0.8 - - - - were inspected and the sites where the left and right 6.6 62.2 67.5 0.92 coronary arteries were to be implanted on the pulmo- LV = left ven~cular;RV = right ventricular. nary artery were marked by reference stitches (Fig 1). During circulatory arrest, the aorta was transected ap- proximately 1 cm distal to the coronary arteries and the graphic evaluation and heart catheterization; LV and RV main pulmonary artery was divided in its midportion. In pressures were measured in all patients, and the LVIRV the neonates, we encountered little discrepancy be- pressure ratios were calculated (see Table). The echocar- tween the sizes of the great arteries. The left and right diogram showed a rightward displacement of the ven- coronary ostia were excised using either a button of tricular septum (type I) in 4 patients (28.6%) and a cen- aortic wall (Fig 2A) or a segment of aortic wall extending trally positioned ventricular septum (type 11) in 10 from the rim of the aortotomy incision to the base of the patients (71.4%). None had a type I11 or leftward dis- coronary sinus (Fig 2B). We made certain to include the placed septum. largest possible segment of aortic wall around the coro- All infants were intubated and artificially ventilated nary ostium. An equivalent oval segment of pulmonary for a minimum of twenty-four hours after operation. arterial wall (previously marked) (Fig 3) was then ex- Postoperative assessment included continuous moni- cised, and the coronary arteries were sutured to the pul- toring of systemic arterial blood pressure, right and left monary artery using a continuous 7-0 polydioxanone atrial pressures, and the ECG. (PDS) suture material. Next, the distal pulmonary artery was brought anterior to the ascending aorta (Lecompte Surgical Technique maneuver) [4], and the proximal pulmonary artery was Deep hypothermic circulatory arrest was used for all ne- anastomosed to the distal aorta using a continuous 6-0 onates. Following a median sternotomy, cardiopulmo- PDS suture (Fig 4). At this point in the operation, the nary bypass was instituted by cannulation of the distal right atrial cannula was replaced and cardiopulmonary ascending aorta and placement of a single venous can- bypass was restarted. During rewarming, the sites of nula through the right atrial appendage. By means of a explantation of the coronary arteries were repaired using heat exchanger interposed on cardiopulmonary bypass, either a patch of circular Gore-Tex (Fig 5A) or a segment core cooling was carried out with cold (15°C) perfusion of pericardium (Fig 5B). Finally, the proximal aorta was until the nasopharyngeal and rectal temperatures sutured directly to the distal pulmonary artery with a reached 20°C. During core cooling, the ductus arteriosus continuous 6-0 PDS suture (see Fig 5). At a rectal tem- was divided and both the left and right pulmonary ar- perature of 36"C, cardiopulmonary bypass was discon- teries were dissected beyond their point of branrhing. tinued. At 20°C the aorta was clamped, cardioplegic solution was infused, and cardiopulmonary bypass was stopped. Results The duration of circulatory arrest ranged from 47 to 64 Deaths minutes. The right atrial cannula was then removed. In There have been 1 hospital death and no late deaths. those patients who had a balloon atrial septostomy, the. The 7-day-old patient died twelve hours after operation. atrial septa1 defect was closed. This patient had an accessory right coronary orifice sup- While the patient was on bypass, the coronary arteries plying a rather large right conal branch. In the attempt to 440 The Annals of Thoracic Surgery Vol 38 No 5 November 1984 Fig 2. The aorta is transected and the lejt and right coronary arteries are excised using (A)either a button of aortic wall or (B) a segment of Fig 4.