The Senning operation for transposition of the great arteries The original Senning technique of interatrial transposition of venous return was selectively employed for physiological correction in 24 patients with transposition of the great arteries (TGA) ranging in age from 74 days to 26 months (median 7 months). Twenty-three had intact ventricular septum and one had a large ventricular septal defect and diaphragmatic subpulmonary stenosis. There were no hospital or late deaths, and at follow-up examination 1.5 to 12 months postoperatively, each patient was asymptomatic, in normal sinus rhythm, and had no clinical evidence of caval or pulmonary venous obstruction. Nine patients underwent cardiac catheterization and angiocardiographic studies between 1.3 and 9 months postoperatively which demonstrated widely patent venous pathways and effective "left" and "right" at rial contraction. This experience lends support to the continued use of the Senning technique for interatrial transposition of venous return.
Lucio Parenzan, M.D. (by invitation), Giuseppe Locatelli, M.D. (by invitation), Ottavio Alfieri, M.D. (by invitation), Massimo Villani, M.D. (by invitation), and Giorgio Invernizzi, M.D. (by invitation), Bergamo, Italy Sponsored by Albert D. Pacifico, M.D., Birmingham, Ala.
JL he operation described by Senning1 in 1959 for correction of transposition of the great arteries (TGA) was recently revived by Quaegebeur, Brom, and coworkers2 and proposed as an alternative to the more widely used technique of Mustard.3 Application of Mustard's procedure to younger and smaller children has resulted in cases of postoperative obstruction to systemic or pulmonary venous return (or both) which has been related to the size, shape, and type of material used for the nonviable interatrial baffle.4, 5 Prosthetic material or avascular pericardium alters the functional capacity of each atrial chamber, cannot increase in size in accordance with patient growth, and may later shrink or undergo fibrous thickening so that the caliber of each venous pathway is reduced. In contrast, the Senning technique employs the right atrial wall and interatrial septum to construct the baffle, whose size is determined by the dimensions of the heart itself. The shape is determined by the technique of the operation and, since viable atrial tissue is used for the From the Departments of Cardiac Surgery and Cardiology, Ospedali Riuniti, Bergamo, Italy. Read at the Fifty-eighth Annual Meeting of The American Association for Thoracic Surgery, New Orleans, La., May 8, 9, and 10, 1978. Address for reprints: Lucio Parenzan, M.D., Department of Cardiac Surgery, Ospedali Riuniti, Bergamo, Italy 0022-5223/78/0376-0305500.70/0 © 1978 The C. V. Mosby Co.
baffle, the capacity to function and grow postoperatively should be preserved. Encouraged by the experience of Brom's group and with these considerations in mind, we began in May, 1977, to selectively employ Senning's technique of interatrial transposition of venous return. Methods Forty-five patients with TGA received surgical treatment at the Department of Cardiac Surgery, Ospedali Riuniti, Bergamo, Italy, between May, 1977, and April, 1978. The surgical procedures performed, diagnosis, and age at operation are shown in Table I. The Senning operation was performed in 24 of these patients, whose ages were between 74 days and 26 months. The age distribution is shown in Table II. Balloon atrial septostomy (BAS) was performed in each patient at the initial cardiac catheterization 2 days to 2 months after birth. One patient in this group had a Blalock-Hanlon septectomy during the first week of life because of failure to improve following BAS. Twentythree patients had transposition with intact ventricular septum; an associated large patent ductus arteriosus with pulmonary artery pressure equal to systemic was present in two, a peak systolic gradient of 20 to 30 mm. Hg between the left ventricle and pulmonary artery was measured in three, and a hemodynamically insignif305
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Fig. 1. The technique of the operation is shown and described in detail in the text. The initial incision (A-B) is extended to the lateral insertion of the Eustachian valve
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Fig. 2. Enlargement of the perimeter of that portion pathway is shown. icant ventricular septal defect was identified angiographically in two. One patient, aged 20 months, had a large ventricular septal defect with severe subpulmonary stenosis from a fibrous diaphragm. The Senning procedure was electively performed in 10 patients and urgently required in 14 because of severe hypoxia and polycythemia, severe heart failure, or a combination of these factors. Postoperatively, patients were evaluated at 1.5 to 3 month intervals by physical examination, electrocardiogram, and chest roentgenogram. Eleven patients were followed for longer than 6 months postoperatively, and nine underwent cardiac catheterization studies 1.3 to 9 months (median 6.3) after operation. Pressures were recorded from each vena cava, the new right atrium, left ventricle, and pulmonary artery in each patient, and from the right ventricle in the single patient with mild elevation of pulmonary artery and capillary wedge pressures. Cineangiocardiograms were made from injection of contrast media into either vena cava and the pulmonary artery in each patient. Twelve patients were rehospitalized 2 to 9 months postoperatively for continuous electrocardiographic monitoring with a magnetic tape recording apparatus for 24 hours. Parents remained with each child and recorded various activities intermittently. Operative technique. The surgical technique employed was essentially that described by Senning1 as modified by Quaegebeur and associates.2 Circulatory arrest for 49 to 60 minutes was established at 20° C. after initial surface-induced deep hypothermia to 24° C. and subsequent limited cardiopulmonary bypass in the 22 patients less than 10 kilograms in weight with uncomplicated transposition. A single venous cannula was initially placed within the right atrial appendage and removed after induction of circulatory arrest. During construction of the caval pathway, a multiholed
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right atrium used to construct the pulmonary venous Table I. Surgical treatment of transposition of the great arteries (May 1, 1977, to April 1, 1978) Diagnosis
Operation
Age (mo.)
No. of patients
Senning Mustard Blalock-Hanlon Mustard, debanding and closure of VSD Senning, closure of VSD, resection of PS Mustard, closure of VSD, LV-PA conduit Rastelli Blalock-Hanlon Blalock-Taussig
2.5-26 7-13 0.07- 2 6-22
23 4* 3 4t
20
1
96,106
2%
59,70 9-34 4-12
2§ 3 3" 45
Legend: TGA, Transposition of the great arteries. IVS, Intact ventricular septum. VSD, Ventricular septal defect. PS, Pulmonary stenosis. LV, Left ventricle. PA, Pulmonary artery. *Each had a previous Blalock-Hanlon septectomy. tEach had a previous Blalock-Hanlon septectomy, each had pulmonary artery banding, and one had repair of coarctation. One patient died. $Noncommitted ventricular septal defect. §One patient died. ||Two patients had a Blalock-Hanlon atrial septectomy.
cannula was placed through the left atrial appendage into the inferior vena cava initially to stent the channel and later to drain blood during the rewarming period. The two remaining patients were operated upon with cardiopulmonary bypass at moderate hypothermia, with intermittent periods of reduced flow and separate direct cannulation of the superior and inferior venae cavae. Hypothermic potassium-induced cardioplegia was a method of myocardial preservation used during the period of aortic occlusion in each case. The right atrium was incised longitudinally, a few millimeters ventral to the sulcus terminalis. Initially,
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Table II. Repair of transposition of the great arteries by the Senning operation
Table III. Postoperative cardiac catheterization data
Hospital deaths Age (mo.) <=3 >3 < 6 >6 < 9 > 9 < 12 >12 Totals
No. of patients
No.
%
70%C.L.*
1 7 6 6 4
0 0 0 0 0
0 0 0 0 0
0%-86% 0%-24% 0%-27% 0%-27% 0%-38%
24
0
0
0%-8%
'Confidence limits.
the incision occupied the cephalad three quarters of the distance between each vena cava. Later, this incision was extended in the direction of the lateral insertion of the valve of the inferior vena cava (Eustachian valve) or if rudimentary, as in three of 24 cases, more anteriorly (Fig. 1, A). The atrial septum was incised to develop a trapezoid flap based at the interatrial groove and having a height of 2 cm. in infants and an apex of 1.5 to 2 cm. (Fig. 1,6). In 19 patients in this series a foramen ovale atrial septal defect was found and was reconstructed with a small Dacron patch (Fig. 1, C). In four patients, the probe-patent foramen ovale was closed by direct suture. One patient had a previous Blalock-Hanlon atrial septectomy and the entire atrial septum was replaced by a trapeziform Dacron patch. The interatrial groove was dissected and the left atrium opened wide by a craniocaudal incision as close as possible to the insertion of the atrial septum (Fig. 1, C). This atriotomy was further enlarged by a short transverse incision betwwen the right pulmonary veins. The previously prepared trapeziform atrial septal flap was sutured anterior to the left pulmonary veins and divergently within the left atrium to its cephalic and caudal origins near each vena cava. Continuous 5-0 silk suture was used (Fig. 1, D). The dorsal edge of the right atrial incision was sutured in the same fashion to the atrial septal remnant between the tricuspid and mitral valve so that the tissue of the Eustachian valve was incorporated inferiorly (Fig. 1, E). The coronary sinus was left to drain with the pulmonary venous blood. The pulmonary venous pathway was constructed by suturing the anterior edge of the right atriotomy to the posterior edge of the left atrial incision with interrupted 5-0 silk sutures. The cranial and caudal portions of the remaining anterior edge of the right atrial incision were sutured very superficially over the respective superior and inferior caval pathways with continuous 6-0 poly-
Pressures (mm. Hg) Patients B.G.t P. D.t P. R. B. M. B. S. F. F. L. S. B. M. L. G.
Postop. (mo.)
SVC*
1.3 4 5.8 6 6.3 7.6 7.7 8.2 9
3 4 3 3 4 2.5 3 3 3
IVC* SVA* 3 5 3 3 4 3.5 2.5 2.5 3
1.5 4 3.5 3 2.5 2 2 2 3
LV
PA
40/0-4 37/0-5 18/0-5 22/0-5 24/0-4 25/0-2 25/0-2 15/0-2 20/0-5
35/15 20/8 17/6 18/6 18/6 20/4 22/6 15/8 18/5
PCW* 10
_ _ 5 4
-
Legend: SVC, Superior vena cava. IVC, Inferior vena cava. SVA, Systemic venous atrium. LV, Left ventricle. PA, Pulmonary artery, PCW, Pulmonary capillary wedge. *Mean pressures. tRight ventricular pressure 80/0-10 mm. Hg. tThis patient had TGA + VSD + PS (subvalvar).
propylene suture (Fig. 1, F). In four cases it was necessary to enlarge the perimeter of the free right atrial wall to avoid narrowing of the venous pathways. This was accomplished in two cases by making an anterior incision perpendicular to the initial atriotomy and in one case by extending the atriotomy upon the atrial appendage (Fig. 2). In one patient who had a previous Blalock-Hanlon septectomy, a small patch of pericardium was used to enlarge the pulmonary venous pathway and to avoid obstruction to the superior vena cava. The patent ductus arteriosus, present in two patients, was doubly ligated at the beginning of cardiopulmonary bypass, and transatrial patch closure of the ventricular septal defect with transpulmonary resection of subpulmonary stenosis was accomplished in the single patient with these associated abnormalities. Results Each patient survived operation and was dismissed from the hospital within 15 days (Table II). Each was extubated within 24 hours, none required postoperative catecholamine support, and none had in-hospital complications. Twenty-three patients had continuous sinus rhythm during early postoperative electrocardiographic monitoring, at the time of discharge, and during late postoperative clinical evaluation. One patient had a junctional rhythm during the early postoperative period but was repeatedly in sinus rhythm at later periodic follow-up examinations. Each patient has remained asymptomatic and without clinical evidence of caval or pulmonary venous obstruction during the follow-up
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Fig. 3. Injection of contrast media into the systemic (A and B) and pulmonary (C and D) venous atrium is shown in atrial systole (B and D) and diastole (A and C). period. Progressive reduction of heart size was noted in each patient having cardiomegaly preoperatively, and digitalis and diuretic therapy used in this group was discontinued by the sixth postoperative month. Postoperative hemodynamic data obtained at cardiac catheterization in nine patients are shown in Table III. There were no significant mean pressure gradients. Pulmonary artery pressure was normal in eight patients and mildly elevated in one who had no difference between pulmonary capillary wedge and right ventricular end-diastolic pressures. This patient had persistent cardiomegaly postoperatively which later regressed. A residual peak pressure difference of 17 mm. Hg remained between the left ventricle and pulmonary artery in the patient who underwent resection of diaphragmatic subpulmonary stenosis. Angiocardiograms demonstrated absence of stenosis of the superior and inferior vena caval pathways and effective contraction of the new left and right atria in each patient (Fig. 3). Intracardiac shunting
was not detected either by angiography or by oximetry. Continuously recorded 24 hour electrocardiograms demonstrated constant sinus rhythm in 10 of 12 patients studied, with changes in heart rate between 70 and 135 beats per minute. In two patients, short episodes of junctional rhythm with rates above 80 beats per minute occurred during sleep. Discussion Our experience with the Senning operation has been a selective one because of our initial reluctance to consider as appropriate candidates those patients having a previous Blalock-Hanlon atrial septectomy, those less than 2 months of age, and those with more complex forms of transposition. However, increased confidence with this procedure makes us now believe the surgical indications are similar to those for Mustard's technique. Patients with previous surgical atrial septectomy are less ideal candidates for the Senning operation, since a larger segment of foreign material is required to
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reconstruct the atrial septum. In addition, the spatial relations between the right pulmonary veins and the venae cavae may be distorted and intrapericardial adhesions may make dissection of the interatrial groove difficult. Therefore, a two-stage surgical approach to the treatment of TGA should be discouraged if the Senning operation is planned as the definitive procedure. Our data support those presented by Quaegebeur and colleagues, 2 demonstrating that this technique can be accomplished with no greater mortality rate than the Mustard operation. Each of our patients had an effective postoperative cardiac output without the need for catecholamine support, which may relate to preservation of the atrial contribution to ventricular filling. Further experience and comparison of measured cardiac output after each method is necessary to define the differences between them properly. The absence of early postoperative rhythm disturbance in all but one of our patients also may have contributed to satisfactory cardiac performance. During the follow-up period, normal sinus rhythm was present in each patient, and minor and transient dysrhythmias have been documented in only two of 12 patients evaluated late postoperatively with continuous 24 hour electrocardiographic recordings. It is controversial whether the sinus rhythm seen after operation actually originates in the sinoatrial node. 6 Following the advice of Clarkson and colleagues, 7 we considered patients to be in sinus rhythm when P waves of uniform shape preceded each QRS complex, the P-R interval was constant, and the frontal-plane P-wave axis was similar to that present preoperatively. A reduced incidence of dysrhythmias and conduction disturbance, probably related to modifications in surgical technique, has been observed following Mustard's operation. 8 - 1 0 Our data support the conclusion that Senning's operation can also be accomplished with minimal trauma to the conducting tissue. Caval and pulmonary venous obstruction has been described following Mustard's operation, usually within the first 12 postoperative months. 5 Although the mechanism causing obstruction may differ in the Senning operation, none of our patients has clinical signs suggesting this complication. Postoperative cardiac catheterization studies performed between 1.3 and 9 months in nine patients have documented the absence of caval and pulmonary venous obstruction. Similar findings were reported by Quaegebeur's group 2 in 19 patients studied within 3 weeks of the Senning operation. In addition, these studies demonstrate effective contraction of the new systemic and pulmonary venous
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atria. Baffle leaks, commonly found after the Mustard operation, have not been identified in our patients. 1 1 ' 1 2 Since the operation utilizes viable atrial tissue (almost completely), appropriate future growth may be expected. The Senning and Mustard procedures leave the right ventricle and tricuspid valve within the systemic circulation. Tricuspid valve incompetence has been described after Mustard's procedure. Although our patients did not have clinical evidence of incompetence or angiographic evaluation of tricuspid valve function, we would not expect this abnormality to differ following the Senning procedure. 13 In addition, late deterioration of right ventricular function remains a potential problem for patients with TGA undergoing either method of interatrial transposition of venous return. Anatomic correction by arterial switching may represent the sole solution to this disturbing problem. 14 In conclusion, this surgical experience with Senning's procedure for TGA demonstrates that it can be accomplished with low hospital risk and relative freedom from dysrhythmias in the majority of patients. Within the period of follow-up, effective atrial contribution to ventricular filling has been preserved and widely patent venous pathways have persisted. These data support the continued use of this technique for interatrial transposition of venous return. We wish to express our gratitude to Professor G. P. Belloli and his associates (Hospital of Vicenza), who participated in the care of nine patients in this series, and to Dr. F. Picchio (University of Bologna) for supplying catheterization data in two patients. REFERENCES 1 Senning A: Surgical correction of transposition of the great vessels. Surgery 45:966-980, 1959 2 Quaegebeur JM, Rohmer J, Brom AG, Tinkelenberg J: Revival of the Senning operation in the treatment of transposition of the great arteries. Thorax 32:517-524, 1977 3 Mustard WT, Keith JD, Trusler GA, Fowler R, Kidd L: The surgical management of transposition of the great vessels. J THORAC CARDIOVASC SURG 48:953-958, 1964
4 McGoon DC: The baffle baffle (editorial). Ann Thorac Surg 23:202-203, 1977 5 Stark J, Tynan M, Ashcraft KW, Aberdeen E, Waterston DJ: Obstruction of pulmonary veins and superior vena cava after the Mustard operation for transposition of the great arteries. Circulation 45:Suppl 1:116-120, 1972 6 El-Said GM, Rosenberg HS, Mullins CE, Hallman GL, Cooley DA, McNamara DG: Dysrhythmias after Mustard's operation for transposition of the great arteries. Am J Cardiol 30:526-532, 1972 7 Clarkson PM, Barratt-Boyes BG, Neutze JM: Late dys-
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rhythmias and disturbances of conduction following Mustard operation for complete transposition of the great arteries. Circulation 53:519-524, 1976 8 Ebert PA, Gay WA Jr, Engle MA: Correction of transposition of the great arteries. Relationship of the coronary sinus and postoperative arrhythmias. Ann Surg 180:433438, 1974 9 El-Said GM, Gillette PC, Cooley DA, Mullins CE, McNamara DG: Protection of the sinus node in Mustard's operation. Circulation 53:788-791, 1976 10 Lewis AB, Lindesmith GG, Takahashi M, Staton RE, Tucker BL, Stiles QR, Meyer BW: Cardiac rhythm following the Mustard procedure for transposition of the great vessels. J THORAC CARDIOVASC SURG 73:919-926,
1977 11 Godman MF, Friedli B, Pastemac A, Kidd BSL, Trusler GA, Musbard WT: Hemodynamic studies in children four
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to ten years after the Mustard operation for transposition of the great arteries. Circulation 53:532-538, 1976 12 Clarkson PM, Neutze JM, Barratt-Boyes BG, Brand PWT: Late postoperative hemodynamic results and cineangiocardiographic findings after Mustard atrial baffle repair for transposition of the great arteries. Circulation 53:525-532, 1976 13 Tynan M, Aberdeen E, Stark J: Tricuspid incompetence after the Mustard operation for transposition of the great arteries. Circulation 45,46:Suppl 1:111-114, 1972 14 Jatene AD, Fontes VF, Paulista PP, Souza LCB, Neger F, Galantier M, Sousa JEMR: Anatomic correction of transposition of the great vessels. J THORAC CARDIOVASC SURG 72:364-370, 1976
(For discussion see page 318)