Surgery for hemodynamic correction of transposition

Surgery for hemodynamic correction of transposition A procedure that preserves atrial conduction pathways The case of a 22-month-old infant with transposition of the great arteries is presented. The anomaly was corrected with a new technique experimentally performed in autopsy hearts and reported by Angelini and Sandijord.r A limited portion of the septum was resected, and only the membrane of the foramen ovale and a strip of its posterior edge were excised. As a result, damage to the anterior and middle atrial pathways was avoided. Intra-atrial inversion was performed with a Dacron tube, which was sutured inside the superior vena cava (SVC) to protect the sinus node and its artery from direct damage. The clinical result was satisfactory, and the patient was dismissed from the hospital in sinus rhythm. He experienced no arrhythmias during his postoperative course. Use of this procedure should help to avoid the rhythm complications which develop after correction of transposition by the Mustard operation.

Guillermo Kreutzer, M.D., * Andres Schlichter, M.D., * Eduardo Galindez, M.D., * Rodolfo Neirotti, M.D., * and Alberto Rodriguez Coronel, M.D., ** Buenos Aires, Argentina

Estoperative arrhythmias continue to be a challenge after corrective'- 2 as well as palliative" surgery for transposition. Several studies of the conduction system':" 14 have allowed the development of new techniques for surgical correction which avoid damage to these structures. Angelini and Sandiford' described a new and interesting method performed in autopsy hearts. They sutured an intra-atrial Dacron tube inside the superior vena cava (SVC), thus preventing damage to the sinus node and its artery'! as well as to the origin of the intra-atrial pathways. We have used this procedure successfully, in conFrom the Unit of Cardiovascular Surgery, Hospital de Ninos, Buenos Aires, Argentina. Received for publication Feb. 20, 1974. Address for reprints: Guillermo Kreutzer, Hospital de Nifios, Gallo 1330, Buenos Aires, Argentina. ·Unit of Cardiovascular Surgery. ··Division of Cardiology, Hemodynamic Section.

junction with deep hypothermia, to correct transposition in a small infant. To our knowledge this is the first report of this technique being used in a patient. Case report A 22-month-old child weighing 9 kilograms was admitted to the Department of Cardiology, Hospital de Nifios, in June, 1973, for treatment of cyanosis since birth and mild dyspnea. At physical examination, cyanosis and clubbing were present and a Grade 3 systolic murmur was audible at the third intercostal space to the right of the sternum. The edge of the liver was 1 em. below the right costal margin. The pulse rate was 145 beats per minute and the arterial pressure was 110/70 mm. of Hg. Chest roentgenography showed increased pulmonary blood flow and an egg-shaped heart (Fig. 1). The electrocardiogram disclosed sinus rhythm, a QRS axis of + 170 degrees, and severe right ventricular hypertrophy. The clinical diagnosis was transposition of the great vessels with minimal pulmonary stenosis. Cardiac catheterization revealed severe systemic desaturation (50.9 per

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Table I. Preoperative and postoperative hemodynamic data Oxygen saturation (per cent)

Pressure (mm. Hg)

Site

Preop.

Postop.

Preop.

Postop,

Superior vena cava Right atrium Right ventricle Aorta Left atrium Left ventricle Pulmonary artery

50.7 45 50.9 50.9 82.5 87.3 90.3

71.5 70.4* 95.5 95.4 97t 71.5 69.4

6 68/5-10 65/35(49) 6 37/2-10 1717(11)

6* 65/0-8 65/40 9t 27/1-7 20/10

*"Venous." t"Arterial."

Fig. 1. Preoperative roentgenogram. cent in the aorta) and systemic pressure in the right ventricle, with a minimal gradient (20 mm. Hg) between the left ventricle and the pulmonary artery (Table I). The saturation of blood in the latter was 90.3 per cent, indicating high flow with low pulmonary vascular resistance. The right and left atrial pressures were similar. On angiocardiography, the pulmonary artery, which had enlarged branches, was found to arise from the left ventricle. Injection into the right ventricle showed that the chamber was well developed and that the aorta filled immediately, confirming the diagnosis of transposition of great arteries with intact ventricular septum. Hemodynamic correction was indicated, and the operation was performed on Oct. 10, 1973. Total anesthesia was induced with thiopental and maintained with halothane and nitrous oxide. The patient was laid on a thermic blanket set at 0° C. and was covered with crushed ice. When the esophageal temperature reached 27° C., the ice bags were removed and a midsternal incision was performed.

Fig. 2. Incision in atrium and cannulation of aorta. The morphology of the heart was that of transposition with slight enlargement of the left atrium and enlargement of both ventricles. The aorta emerged anteriorly from the right ventricle, and the pulmonary artery arose posteriorly from the left ventricle. The left coronary artery passed in front of the pulmonary annulus. A soft systolic thrill was present on the pulmonary artery. The ascending aorta and the right and left atrial appendages were cannulated, and perfusion (2.4 L. per minute per square meter at 12° C.) was established with a disc oxygenator and roller pump primed with whole fresh heparinized blood. A tape was passed around the SVC just above the azygos vein.

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b

a

Fig. 3. a, The right atrium is opened and the atrial conduction pathways can be seen. Dotted line marks limits of septal resection. b, Posterior Dacron patch is in place between the left pulmonary veins and mitral annulus. Two stitches have already been passed through the graft.

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Fig. 4. a, The tube has been lowered and sutured to the Dacron patch. b, Suture of the tube to the anterior edge of the septum and atrial wall is marked by the dotted lines. The coronary sinus was left on the systemic side. The lowest part of the graft covered the orifice of the inferior vena cava. The graft was passed through a transverse incision on the superior vena cava. It was then stretched and the remnant excised. The posterior row of sutures was placed.

After 5 minutes (at which point a temperature of 19° C. had been reached), the aorta was crossclamped, perfusion stopped, and blood allowed to flow into the oxygenator. An incision extending from the right atrial appendage down to the inferior vena cava (IYC) (Fig. 2) disclosed a 1.5 em. patent foramen ovale. Only the membrane of the fossa ovalis and the posterior ridge of the septum were excised; the anterior edge was avoided to preserve the middle atrial

conduction pathway (Fig. 3). A 25 by 12 mm. Dacron patch was sutured with 5-0 Dacron to the posterior wall of the left atrium between the left atrial appendage, the mitral valve, and the pulmonary veins (Fig. 3, b). Then, the lower two thirds of a 12 mm. woven Dacron tube (the same diameter as the SYC) was incised. The tube was then fixed with a running suture (Fig. 4, a) to the septal edge, to the previous patch, and to the posterior wall of the atrium with its lowest part

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at.

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V2

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Fig. S. Postoperative electrocardiogram shows sinus rhythm.

a 19 minute rewarming period, at which time a temperature of 33° C. had been reached. The postoperative course was uneventful , and the patient was dismissed, acyanotic, on the fourteenth postoperative day. A soft systolic pulmonary murmur was audible. The chest roentgenogram was normal. The electrocardiogram (Fig . 5) showed sinus rhythm. At recatheterization, no intracardiac shunting was demonst rable. Injection into the SVC showed filling of the left ventricle and the pulmonary artery through the intra-atrial Dacron graft and the mitral valve (Fig. 6).

Fig. 6. Postoperative angiogram: Injection into the superior vena cava shows filling of the left ventricle and the pulmonary artery through the graft. No obstruction is visible. around the IVe. The coronary sinus was left on the systemic side (Fig. 4, b) . A transverse incision was then made in the SVC between its entrance into the right atrium and the azygos vein. The upper part of the Dacron tube was stretched and passed through the SVC and the remnant was excised. The tube was then sutured to the posterior wall of the vein, and the cava and graft were closed with running sutures (Fig . 4, b) . The auriculotomy was closed and perfusion re-established with the venous cannula in the left atrial appendage after a total circulatory arrest period of 61 minutes . The heart was in sinus rhythm. Perfusion was terminated after

Discussion

Mustard's" intra-atrial inversion procedure is the technique most frequently used for hemodynamic repair of transposition, although a number of postoperative complications have been reported since 1964. The most important of these may be divided into three different groups: ( 1) arrhythmias secondary to lesions of the sinus node or the intra-atrial or atrioventricular conduction systems; (2) obstruction to the pulmcnary" and/or systemic" venous return caused by shrinkage of the intra-atrial pericardial baflle; and (3) tricuspid insufficiency. Our experience encompasses 27 Mustard

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operations. Sixteen (59.2 per cent) of the patients presented postoperative arrhythmias. Since 1972, we have used the same technique but with one difference: the coronary sinus was left on the systemic side in 10 cases. However, 6 of the patients developed arrhythmias. Therefore, the variation did not produce the expected decrease in postoperative arrhythmias (60 per cent). Other surgical teams have abandoned the pericardial patch, instead using synthetic material" to avoid shrinkage of the baffle. Surface- and perfusion-induced deep hypothermia with total circulatory arrest has been a valuable method for the treatment of infants under 2 years of age1 5 - 1 8 who have complex cardiac malformations. A bloodless surgical field, the absence of cannulas during the operation, and the low risk of the procedure are only some of the advantages of this method. Nevertheless, some surgical groups continue correcting this pathology via normothermia with good results.P During Mustard's procedure the sinus node may be damaged either directly or indirectly: Direct damage may be inflicted during cannulation of the sve, which has to be high, whereas indirect damage may occur if suture of the intra-atrial baffle involves the sinus node artery." However, if the operation is performed with the aid of deep hypothermia, it is impossible to injure the sinus node directly, because only the atrial appendage is cannulated. Angelini and Sandiford' reported an experimental method for correction of transposition which they performed in autopsy hearts. The sve is intubated with a Dacron graft through which blood flows to the mitral valve. In this way the use of sutures is avoided around the sinus node, from which the three principal interatrial pathways arise, The lower two thirds of the graft is incised and sutured to the posterior wall of the atrium, thereby allowing the newly formed "right" atrium to grow. The sve has to be encircled extrapericardially just above the azygos vein to allow the upper anastomosis of the graft.

In our patient, less of the atrial septum was resected than is necessary for the Mustard technique, and only the membrane of the foramen ovale together with its posterior edge was excised. This technique probably damages the posterior intra-atrial pathway, as they are also included in the suture line when the graft is fixed by the coronary sinus. In order to protect the anterior and middle pathways, the anterior ridge should not be resected. Furthermore, care should be taken to ensure that the graft is sutured to the anterior edge of the foramen ovale only. The tube should be as large as possible in diameter, i.e., equal to the internal diameter of the sve. The use of a smaller graft could cause progressive venous obstruction. In this event, the presence of the azygos vein cefalad to the Dacron tube could encourage the development of collateral circulation to the IVe. 7 An advantage of the use of the Dacron tube is that the possibility of pulmonary venous obstruction is almost negligible. Because the prosthetic graft is used in a low-pressure, and slow-flow territory, the superior vena cava, thrombosis is another possible complication. In our patient, catheterization performed on the twenty-third postoperative day showed absolute patency of the graft, with no obstruction to either the pulmonary or systemic blood flow. It also revealed normal pressure and normal oxygen saturation in all cardiac chambers (Table I). We would like to acknowledge the assistance of Dr. Florentino Sanguinetti. We also wish to thank The Fundacion Cardiologica Infantil for financial support.

Addendum Since the submission of this paper for publication, we have operated upon 6 other patients, 5 with the aid of deep hypothermia and 1 with normothermia. In the last patient, the SVC was cannulated extrapericardially and the azygos vein was snared temporarily. The incision in the right atrium was modified to extend toward the left atrium, between both right pulmonary veins, and to cross through the interatrial sulcus. The distal end of the atriotomy was enlarged with a dia-

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mond-shaped pericardial patch to prevent a possible future obstruction to pulmonary venous return. One of the patients with transposition of the ventricular septal defect and severe pulmonary hypertension died of respiratory distress. The other 5 patients are doing well and are in sinus rhythm. REFERENCES

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Aberdeen, E., and Waterston, D. 1.: Obstruction of the Pulmonary Veins and Superior Vena Cava After Mustard Operation for Transposition of the Great Arteries, Circulation 44: 91, 197 I. 10 Berman, M. A, Taylor, J. F. N., Talner, N. S., and Stansel, H. C.: Successful Repair of Pericardial Patch Stenosis After Mustard Procedure, J. THORAC. CARDIOVASC. SURG. 65: 276, 1973. 11 Kennel, J. K, and Titus, 1. L.: The Vasculature of the Human Sinus Node, Mayo Clin. Proc. 47: 556, 1972. 12 Kilman, J. R, Williams, T. E., Kakos, G. S., Craenen, J., and Hoisier, D. M.: Surgical Correction of the Transposition Complex in Infancy, J. THORAC. CARDIOVASC. SURG. 66: 387, 1973. 13 Rodriguez Coronel, A., and Miller, R. A.: Accelerated Nodal Pacemaker, Pediatrics 43: 430, 1969. 14 Titus, 1. L.: Normal Anatomy of the Human Cardiac Conduction System, Mayo Clin. Proc. 48: 24, 1973. 15 Subramanian, S., Wagner, H., Vald, P., and Lambert, E.: Surface-Induced Deep Hypothermia in Cardiac Surgery, 1. Pediatr. Surg. 6: 612, 1971. 16 Mohri, H., Dillard, D. H., Crawford, E. W., Martin, W. E., and Merendino, K A: Method of Surface-Induced Deep Hypothermia for Open-Heart Surgery in Infants, J. THORAC. CARDIOVASC. SURG. 58: 262, 1969. 17 Barratt-Boyes, B. G., Simpson, M. M., and Neutze, J. M.: Intracardiac Surgery in Neonates and Infants Using Deep Hypothermia, Circulation 42: 73, 1970 (Suppl, III). 18 Barratt-Boyes, B. G., Simpson, M. M., and Neutze, J. M.: Intracardiac Surgery in Neonates and Infants Using Deep Hypothermia in the Surface Cooling and Limited Cardiopulmonary Bypass, Circulation 43: 25, 1971 (Suppl, I).