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Ann Thorac Surg 2002;73:855-860
© 2002 The Society of Thoracic Surgeons
a Department of Cardiovascular Surgery, Tokyo Womens Medical University, Heart Institute of Japan, Tokyo, Japan
b First Department of Surgery, Yokohama Municipal University, School of Medicine, Kanagawa, Japan
Accepted for publication October 23, 2001.
* Address reprint requests to Dr Hiramatsu, Department of Cardiovascular Surgery, Tokyo Womens Medical University, Heart Institute of Japan, 8-1 Kawada-cho, Shinjuku-ward, Tokyo, 162-8666 Japan
e-mail: shiramat{at}hij.twmu.ac.jp
| Abstract |
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Methods. Twenty-five patients were treated by the Fontan procedure with SVOO. Twenty-one patients had undergone prior pulmonary artery banding and 10 patients had undergone prior arch repair. Systemic ventricular outflow obstruction progressed in 5 patients after the Fontan procedure. Main diagnosis was single ventricle in 12, tricuspid atresia in 5, transposition of the great arteries in 4, double-outlet right ventricle in 3, and common atrioventricular canal in 1. Mean age at operation was 6.5 years (range 1 to 15 years) and the average preoperative pressure gradient across the ascending aorta and systemic ventricle was 29 mm Hg (range 0 to 100 mm Hg). The Damus-Kaye-Stansel procedure was performed in 18 patients (double-barrel anastomosis in 13, end to side anastomosis in 5), and subaortic resection or ventricular septal defect or bulboventricular foramen enlargement was performed in 7. Double-barrel anastomosis has been our first choice since 1994, if the pulmonary valve is intact. Follow-up has ranged from 4 months to 14 years (average 5.0 years). Twenty-three of the 25 patients have undergone recatheterization (average 21.4 months later).
Results. No early deaths were found; one late death was reported of a patient with single right ventricle (4.0%). The postoperative average pressure gradient was 1.1 mm Hg (0 to 10 mm Hg), and the average right atrial pressure was 14 mm Hg (9 to 20 mm Hg). In all patients who underwent ventricular septal defect or bulboventricular foramen enlargement, regular sinus rhythm was maintained postoperatively. Regarding the Damus-Kaye-Stansel procedure, there was minimal progression of semilunar valve insufficiency except in 1 patient who underwent end-to-side anastomosis with moderate pulmonary regurgitation postoperatively.
Conclusions. The midterm results of the Fontan procedure with SVOO have been satisfactory. Because SVOO might progress after the Fontan procedure if there is morphologic obstruction, an appropriate strategy to relieve obstruction to systemic blood flow should therefore be performed concomitantly with the Fontan procedure.
| Introduction |
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| Patients and methods |
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Operative technique
The operations were performed under moderate hypothermic cardiopulmonary bypass (rectal temperature, 28° to 30°C). Ascending aortic and bicaval cannulation was performed, and the perfusion flow rate was 2.2 to 2.4 L/m2 per minute. Crystalloid cardioplegia and topical myocardial cooling were used in all patients. Cardioplegia was repeated at 40-minute intervals. Relief of SVOO involved two techniques. If the pulmonary valve had no anatomic deformity, the DKS procedure was performed (n = 18, the DKS group, Fig 1). The main pulmonary artery was divided at its bifurcation or the previously banded site, when present. Construction of the aortopulmonary anastomosis was performed in a classic end-to-side fashion (n = 5) with a sufficient length of pulmonary artery. Ventricular septal defect enlargement and SAS resection were performed concomitantly in 2 of these 5 patients. In the remaining patients (n = 13), the aorta was transected at a corresponding level above the sinuses of Valsalva and half of both facing great arteries was anastomosed in side-to-side fashion, and the distal aorta was sutured to the new bivalved artery without any prosthetic material (Lambertis modification or double-barrel anastomosis) [4, 5, 7]. This double-barrel anastomosis has been our first choice since 1994, if the pulmonary valve is intact. When the pulmonary valve was deformed or the pulmonary trunk was too short, resection of subaortic muscle or enlargement of VSD or BVF was performed (n = 7, the resection group) (transaortic in 3 patients, trans-outlet chamber in 3 patients, and transatrial in 1 patient). To avoid conduction disturbances, the anterior corner of the VSD was enlarged mainly in patients with posterior atrioventricular conduction, and the posterior corner of the BVF in patients with anterior atrioventricular conduction (single left ventricle).
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| Results |
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In the 23 patients who underwent recatheterization postoperatively (17 patients in the DKS group and 6 patients in the resection group), the average pressure gradient across the systemic ventricle and ascending aorta was 1.1 mm Hg (0 mm Hg in the DKS group and 0 to 10 mm Hg in the resection group). The average end-diastolic volume of the systemic ventricle was 112% of normal (59 to 299% of normal in the DKS group and 65 to 131% of normal in the resection group) and significantly smaller than the preoperative value (p < 0.05). The average ejection fraction of the systemic ventricle was 0.50 (0.32 to 0.74 in the DKS group and 0.42 to 0.55 in the resection group). The average cardiac index was 2.4 L · min-1 · m-2 (1.8 to 3.5 L · min-1 · m-2 in the DKS group and 1.7 to 2.7 L · min-1 · m-2 in the resection group), and the average right atrial pressure was 14 mm Hg (9 to 19 mm Hg in the DKS group and 10 to 20 mm Hg in the resection group). None of these measurements was statistically different between the two groups.
Systemic ventricular outflow obstruction progressed in 5 patients after the Fontan procedure (single left ventricle, n = 4; common atrioventricular canal, n = 1; 26 to 140 months, average 66 months later), even though no pressure gradient had been recognized initially. Two patients had a normal pulmonary valve and underwent the DKS procedure (1 with end-to-side anastomosis, 1 with the double-barrel anastomosis). The other 3 patients, who had a deformed pulmonary valve or short pulmonary trunk, underwent subaortic resection or enlargement of the BVF.
In the 7 patients who underwent subaortic resection or VSD or BVF enlargement, only 1 patient who underwent SAS resection, showed temporary atrioventricular block and required temporary pacing postoperatively, but sinus rhythm was restored about 1 month later and regular sinus rhythm was maintained postoperatively in all cases. Restenosis of VSD occurred in 1 patient (patient no. 19, TA2b) and reenlargement of VSD was performed twice, 21 months and 4.5 years, respectively, after the initial operation. In the other 6 patients no evidence of recurrent obstruction was found from two-dimensional echocardiography in the outpatient clinic.
Postoperative semilunar valve insufficiency was evaluated by two-dimensional echocardiography in 18 patients in the DKS group (Table 2). The 5 patients who underwent end-to-side anastomosis showed none to trivial aortic regurgitation (Ar). One patient showed none to trivial old pulmonary regurgitation (Pr), and 3 showed mild Pr. One patient showed moderate Pr, but was followed in the outpatient clinic without medication. Only 1 of the 13 patients who underwent double-barrel anastomosis showed mild Ar, but had shown the same degree of Ar preoperatively; he was found to have none to trivial Pr. The other 11 patients exhibited none to trivial Ar and Pr postoperatively.
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| Comment |
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Some of the lesions included in this series are unlikely to have subaortic obstruction, such as tricuspid atresia 1c and TGA with hypoplastic LV. Patient 3 was diagnosed as having d-TGA4 (intact ventricular septum and infundibular pulmonary stenosis) and small LV (56% of normal), so that the Fontan procedure was indicated and the DKS anastomosis was performed concomitantly because resection of LV outflow tract obstruction was not feasible. Patients 14 and 18 were diagnosed as having tricuspid atresia 1c, but they underwent coarctation or interruption of the aorta repair and pulmonary artery banding previously and they had mild SVOO (pressure gradient = 5 mm Hg) hemodynamically so that the DKS anastomosis was performed. Furthermore, the outcome after the Fontan procedure with SVOO in our series was satisfactory and similar with the outcome of patients with functional single ventricle without SVOO and the relief of SVOO should be performed at the Fontan procedure when SVOO was suspected anatomically or hemodynamically.
The DKS anastomosis is an attractive option for ensuring unobstructed blood flow from the systemic ventricle in patients with complex congenital heart disease, and the procedure has been applied to patients with several forms of complex congenital heart disease in which systemic blood flow is obstructed. DKS anastomosis is especially suitable for patients in whom the Fontan connection is planned, because the method avoids surgical trauma to the myocardium and relieves systemic outflow obstruction, thereby obviating further cardiac hypertrophy and diastolic dysfunction.
The technique used to perform the pulmonary artery-aorta connection should be selected on an individualized basis with the goal of avoiding outflow tract gradients and distortion of the semilunar valves. However, the effect of the DKS anastomosis on the midterm function of the semilunar valves is unknown. Carter and colleagues [7] reported a 0% incidence of aortic insufficiency in 18 patients with palliation of single ventricular anatomy. In our series, 1 of the 5 patients who underwent the end-to-side anastomosis showed moderate old pulmonary insufficiency and 3 showed mild old Pr, whereas none of the 13 patients who underwent the double-barrel anastomosis, except 1 patient who had mild Ar preoperatively, showed significant Pr and Ar postoperatively. From these observations of the semilunar valve after the DKS procedure, the double-barrel method seems to be an ideal modification.
Most surgical teams recommend obliterating the pulmonary valve at the time of transection of the pulmonary artery in functional single ventricle, designed to eliminate a "pulmonary pouch." If there is a possibility of late SVOO, a prophylactic DKS should be performed concomitantly, or at least the pulmonary valve should not be obliterated for a future DKS.
If the pulmonary trunk is too short or the pulmonary valve is severely deformed, resection of SAS or enlargement of VSD or BVF should be considered. Although enlargement of the BVF entails the risk of complete heart block, difficulty in determining the extent of resection, myocardial dysfunction secondary to ventriculotomy, and the potential for recurrent obstruction, none of the patients in our series showed complete heart block or severe ventricular dysfunction. Careful examination of the anatomy, including preoperative electrophysiologic studies and appropriate surgical intervention, such as transaortic or trans-outlet chamber resection of the muscle, are necessary to prevent conduction disturbance and myocardial dysfunction. Pass and coworkers [10] reported the results of direct surgical BVF resections and 3 of 9 patients required reoperation for reobstruction at the BVF, and 1 patient developed Mobitz II heart block requiring postoperative implantation of a pacemaker. In our series only 1 patient with TA (2b) had recurrent obstruction of VSD, and the VSD was reenlarged twice. Although there has been no evidence of recurrent obstruction in the other 6 patients who underwent SAS resection or VSD enlargement thus far, careful follow-up is needed for recurrent obstruction in the SAS release group.
In our series, SVOO progressed in 5 patients after the Fontan procedure. The amount of blood flow across the systemic atrioventricular valve after the Fontan procedure decreased and ventricular volume also decreased to 60% to 70% of its preoperative level [11], allowing insidious SAS or VSD obstruction to progress after the Fontan procedure. Even when no SAS was present at the time of the Fontan procedure, it sometimes developed postoperatively, especially in single left ventricle after pulmonary artery banding, and so that we had adopted a policy of relieving obstruction to systemic blood flow during the Fontan procedure whenever there was morphologic stenosis, even in the absence of a pressure gradient. The natural history of the BVF or the subaortic region in the single heart with TGA and similar anomaly suggests that prophylactic DKS anastomosis or SAS resection or VSD enlargement may be appropriate concomitant with the Fontan procedure.
Many centers favor the approach of staging toward the Fontan procedure, with early relief of SVOO usually at the time of the bidirectional Glenn procedure (BDG). When the treatment is staged, SVOO should be dealt with at the time of the BDG. However, we usually choose not to stage patients with functional single ventricle and our indication of the BDG is limited to patients with severe atrioventricular valve regurgitation and large ventricular volume. Mendelsohn and colleagues [12] noted a 32% decrease in the Nakata index of total cross-sectional pulmonary artery area after the BDG, thus changes in pulmonary artery size might influence the Fontan outcome. If relief of SVOO is mandatory in the neonate or infant with functional single ventricle and SVOO, our policy is to perform either VSD enlargement or a DKS anastomosis with atrial septal defect creation or Blalock-Taussig shunt. In our series, 1 patient (no. 12) underwent enlargement of BVF and creation of an atrial septal defect at 1 month old and underwent the Fontan procedure and a prophylactic DKS anastomosis at 3 years old. We had 2 other patients with functional single ventricle and SVOO undergoing a double-barrel anastomosis and modified Blalock-Taussig shunt at 3 and 8 months old. We lost 1 patient 2 years later due to a bacterial infection and another patient was waiting for the Fontan procedure, and postoperative catheterization of both patients showed no pressure gradient across the systemic ventricle and ascending aorta and minimal semilunar valve insufficiency. Therefore, the optimal timing for the relief of SVOO depends on the patients condition and the appropriate surgical relief should be performed even in the neonatal period if necessary. In our series the youngest ages of enlargement of BVF and double-barrel anastomosis were 1 and 3 months old, respectively. Because pulmonary artery banding has been suggested in promoting ventricular hypertrophy and altering the wall mass/volume index recently, an appropriate surgical relief of SVOO might be considered earlier in life to prevent the onset of severe ventricular hypertrophy in patients with certain anatomic subtypes if necessary.
In summary, the midterm results of the Fontan procedure with SVOO have been satisfactory. Systemic ventricular outflow obstruction sometimes progresses after the Fontan procedure if there is morphologic obstruction, and an appropriate strategy to relieve obstruction to systemic blood flow should be performed concomitantly with the Fontan procedure. Minimal progression of semilunar valve insufficiency occurs after the double-barrel anastomosis, which seems to be an ideal option if the pulmonary valve has no deformity.[6]
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