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Ann Thorac Surg 1998;65:1115-1119
© 1998 The Society of Thoracic Surgeons
a Clinic for Thoracic and Cardiovascular Surgery, University Hospital, Berne, Switzerland
b Department of Cardiac Surgery, Children’s Hospital, Helsinki, Finland
Accepted for publication November 11, 1997.
Address reprint requests to Dr Carrel, Clinic for Thoracic and Cardiovascular Surgery, University Hospital, CH-3010 Berne, Switzerland.
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Abstract |
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 TopFootnotes Abstract IntroductionPatients and methodsResultsCommentReferences |
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Methods. Between 1990 and June 1996, a total of 189 patients underwent the arterial switch procedure because of D-transposition of the great vessels. Of them, 47 underwent direct pulmonary artery reconstruction. Mean age at operation was 5.2 ± 4.1 days and mean weight was 3.75 ± 0.85 kg. Simple transposition of the great arteries was present in 13, transposition of the great arteries plus ventricular septal defect in 27, and more complex forms of transposition of the great arteries in 7 patients. The great vessels were side-by-side in 4 patients and in the anteroposterior position in 43 patients. The technique of direct pulmonary reconstruction includes extensive mobilization of both pulmonary artery branches into the hilum, posterior incision of the mean pulmonary artery into the bifurcation, and resuspension of the posterior commissure of the neo-pulmonary valve. A large anastomosis without any tension is then performed, using the anterior remnant aortic sinus of Valsalva to fit out the expected size of the neo-pulmonary artery.
Results. Early mortality was 8.5% (4/47) in this particular group of patients. Postoperative echocardiography was performed before hospital discharge, 3 to 6 months postoperatively, and after a mean follow-up of 24 months. Of the 43 survivors, 37 patients had a pressure gradient across the pulmonary valve of less than 15 mm Hg. Mild pulmonary stenosis (pressure gradient of 15 to 30 mm Hg) was present in 4 and more severe supravalvar stenosis (pressure gradient > 30 mm Hg) in 2 patients. After a mean follow-up of 36 months, there was one redo operation to enlarge the right ventricular outflow tract.
Conclusions. Direct reconstruction of the neo-pulmonary artery—avoiding autologous pericardium and prosthetic material—may represent an interesting option during the arterial switch operation when the great vessels lie in the anteroposterior position. This technique is simple, and the hemodynamic midterm results are very favorable. The incidence of postoperative supravalvar pulmonary stenosis is low, and there may be considerable potential for unlimited tissue growth.
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Introduction |
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TopFootnotesAbstractIntroductionPatients and methodsResultsCommentReferences |
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We present our experience with this technique in a limited group of patients.
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Patients and methods |
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TopFootnotesAbstractIntroductionPatients and methodsResultsCommentReferences |
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Simple TGA was present in 13, TGA plus VSD in 27, and more complex forms of TGA in 7 patients, including aortic coarctation (n = 4), interrupted aortic arch (n = 1), and double-outlet right ventricle configuration (n = 2). The great vessels were side-by-side in 4 patients and in the anteroposterior position in 43 patients.
Surgical technique
Patient selection for this alternative technique was chosen by the surgeon, depending on the amount of tissue available from the PA and the position of the coronary arteries after reimplantation in the neo-aorta. Before extracorporeal circulation is started, the main PA and the left and right branches are dissected free into the lung hilus, including the upper lobe artery. Posteriorly, the pericardial reflection of the transverse sinus is dissected free and the surrounding tissue is completely excised. Cardiopulmonary bypass is initiated after aortic and bicaval cannulation and conducted in deep hypothermia. Myocardial protection includes intermittent antegrade cold blood cardioplegia and warm blood cardioplegia before reperfusion.
The aorta is transected 2 to 4 mm above the commissures, and the coronary ostia are excised with a generous portion of the corresponding sinus of Valsalva (Fig 1). The main PA is divided 2 to 4 mm under the bifurcation, and coronary ostia are reimplanted at an appropriate place in the neo-aorta (Fig 2). The distal pulmonary artery is then brought anterior to the aorta (Lecompte maneuver). If the coronary ostia are located close to the posterior commissure, excision may include a segment of the posterior commissure of the native aortic valve; this leads only rarely to pulmonary regurgitation, which is usually mild and well tolerated. The VSD was closed through an atriotomy in 15 patients and through the transected aorta in 14 patients.
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where the observed dimension is the dimension measured in the patient who is of a known size (body surface area) and the mean normal dimension and standard deviation refer to values in normal persons of the same body surface area as the patient, obtained from specific solutions of regression equations derived from the analyses of measurements made in individuals comprising a sample of normal persons [3]. The comparison of Z scores of the main pulmonary artery preoperatively and postoperatively may be interpreted as an indicator of postoperative growth. Complete assessment of these values could be performed in 20 of the 43 survivors. |
Results |
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TopFootnotesAbstractIntroductionPatients and methodsResultsCommentReferences |
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Extubation could be performed after a mean postoperative interval of 4.9 ± 1.9 days (extending from 2 to 10.1 days). Hemodynamic support was administered routinely and consisted of dopamine and nitroglycerin. If necessary, low-dose epinephrine was given to support early postoperative left ventricular contractility. Revision because of bleeding was necessary in 2 patients.
Mortality and morbidity
Early mortality was 8.5% (4/47); no postoperative complication could be directly related to the type of pulmonary repair. Mortality was not higher than in the group with pericardial patch reconstruction of the PA. Two patients died immediately postoperatively of intractable left ventricular failure, but autopsy could not demonstrate any sign of ongoing myocardial ischemia. In the early experience, 1 patient with intramural left coronary artery and single coronary artery died of left ventricular infarction. Postoperative myocardial infarction was observed in a patient on postoperative day 25. At angiography, obstruction of a nondominant left coronary artery was demonstrated. However, this patient is doing well clinically 1.5 years later, and left ventricular function is satisfactory with an ejection fraction of 0.50. One late death occurred after 11 months because of persistent chylothorax, which had developed after superior vena cava thrombosis. This child had to be reintubated several times and had development of respirator-induced pneumopathy.
Reoperations
One patient had to be reoperated on because of a significant residual VSD 3 months after the arterial switch operation, and another patient underwent patch enlargement of a supravalvular pulmonary stenosis (maximal pressure gradient, 60 mm Hg; interval after the switch operation, 16 months).
Functional status
The operative survivors have been followed up by their referring pediatric cardiologists or in the pediatric cardiologic clinic of University Hospital, Berne. The length of follow-up ranged from 6 to 66 months (mean, 36 ± 11 months). Forty of 42 long-term operative survivors are in New York Heart Association functional class I without medication. All patients demonstrate sinus rhythm. Ten of 21 of the operative survivors with D-TGA and VSD have right bundle-branch block.
During the last follow-up echocardiographic examination, left ventricular contractility, dimensions of the left ventricle, and shortening fraction were within normal ranges in 39 patients. However, some degree of septal hypokinesia or dyskinesia was seen in 7 patients.
Ventricular outflow tract
Right and left ventricular outflow tracts were assessed routinely by color Doppler echography. Echocardiography was performed before hospital discharge and after a mean follow-up of 24 months (Berne, 12 months, Helsinki, 39 months). Thirty-seven patients had a pressure gradient across the pulmonary valve of less than 15 mm Hg. Pressure gradients between 15 and 30 mm Hg were present in 4, and severe supravalvar stenosis (pressure gradient > 30 mm Hg) in 2 patients. Trivial pulmonary regurgitation was present in 12 patients.
Until now, one redo operation has been necessary and has been reported above. The influence of the surgical technique on the incidence of right ventricular outflow tract stenosis was assessed, comparing the patients who had undergone direct PA reconstruction (n = 43 survivors) with the group of 128 patients with a more classic PA reconstruction at a similar follow-up interval (body weight, length, and body mass area were comparable between these two groups). Main PA growth was comparable to the growth of the PA after interposition of a pericardial patch. No pulmonary branch stenosis was observed in this series. Estimation by comparison of postoperative evolution of Z scores gives a growing factor of 1.5 ± 0.25 in the direct reconstruction group versus 1.25 ± 0.22 in the classic group.
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Comment |
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TopFootnotesAbstractIntroductionPatients and methodsResultsCommentReferences |
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The classic PA reconstruction consists generally in filling the defects left by coronary ostia explantation sites with a single, long, inverted bifurcated pericardial patch (called by some authors the pantaloon patch) or in some occasions with two separate pericardial patches.
Planché and co-workers [4] described the occurrence of supravalvar pulmonary stenosis after the explantation sites were closed with small pericardial patches but absence of this complication after reconstruction with a single large piece of pericardium. An incision is usually made into the pericardium to fit into the posterior commissure and the free pericardial edge is sutured to the area of the aorta corresponding to the explanted coronary buttons. The pericardial patch is then tailored to bridge the distance between the proximal neo-pulmonary artery and the distal native PA without tension. However, despite a tensionless anastomosis, severe stenosis may still appear in the first 24 months after the operation.
The technique of direct PA reconstruction has been previously described [1] in 6 children with TGA and VSD. This technique was abandoned for many reasons. In our experience, direct reconstruction should not be attempted when the Lecompte maneuver cannot be performed. In these cases, the use of a single pericardial patch facilitates PA reconstruction considerably.
Although the majority of neonates having had an arterial switch operation for transposition of the great arteries have normal development and cardiac function, a few will require subsequent reoperation. In this group of patients, early and late postoperative development of subvalvular and supravalvular pulmonary stenosis may represent the main cause of reoperation [6–10]. Supravalvular pulmonary stenosis is generally treated by patch insertion.
In contrast to our own observation, Serraf and co-authors [9] were able to identify the technique of direct anastomosis without patch insertion as a risk for subsequent development of pulmonary stenosis. However, the level of significance in univariate analysis was low (p < 0.05). The mean interval between the arterial switch and reoperation was 14 months (ranging from 1 to 90 months). In the multivariate analysis, only the presence of a hypoplastic native aortic annulus as opposed to the native pulmonary annulus was a risk factor for postoperative pulmonary stenosis and reoperation. Although the majority of patients had no or only mild symptoms, the decision to relieve pulmonary stenosis was taken when the gradient was 60 mm Hg or greater. We believe that our incidence of right ventricular outflow tract stenosis requiring operation is acceptable and comparable with that found in the literature: it is 2.1% after direct PA reconstruction and 5.4% in the group with pericardial patch PA reconstruction. The potential risk of compressing a coronary artery must be evaluated from case to case [10]. Although we cannot exclude this cause in the immediate postoperative course, autopsy failed to demonstrate myocardial ischemia in 2 cases of early postoperative death.
A certain limitation of our observation may be the length of the follow-up, which is rather short. However, in the study by Serraf and co-workers [9], all patients who required reoperation demonstrated early occurrence of pulmonary stenosis (within the first postoperative year with progressive accentuation).
In conclusion, during the arterial switch operation, direct reconstruction of the neo-pulmonary artery—avoiding autologous pericardium and prosthetic material—may represent an interesting option in TGA with anteroposterior position of the great vessels and with excessive PA tissue (eg, Taussig-Bing hearts, TGA with VSD). This technique also has been used in simple TGA when the coronary ostia have been reimplanted well laterally in the neo-aorta. The hemodynamic results are favorable. The incidence of postoperative supravalvar pulmonary stenosis is low, and there may be a considerable potential for unlimited tissue growth because of the complete absence of foreign material.
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TopFootnotesAbstractIntroductionPatients and methodsResultsCommentReferences |
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References |
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  M. V. Ullmann, M. Gorenflo, C. Bolenz, C. Sebening, M. Goetze, R. Arnold, H. E. Ulmer, and S. Hagl Late Results After Extended Pulmonary Artery Reconstruction in the Arterial Switch Operation Ann. Thorac. Surg., June 1, 2006; 81(6): 2259 - 2266. [Abstract] [Full Text] [PDF]
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S. K. Gandhi, F. A. Pigula, and R. D. Siewers Successful late reintervention after the arterial switch procedure Ann. Thorac. Surg., January 1, 2002; 73(1): 88 - 95. [Abstract] [Full Text] [PDF]
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F. Haas, M. Wottke, H. Poppert, and H. Meisner Long-term survival and functional follow-up in patients after the arterial switch operation Ann. Thorac. Surg., November 1, 1999; 68(5): 1692 - 1697. [Abstract] [Full Text] [PDF]
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