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Ann Thorac Surg 2001;72:424-429
© 2001 The Society of Thoracic Surgeons

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Original article: cardiovascular

Anatomically corrective repair of complete atrioventricular septal defects and major cardiac anomalies

^a Department of Cardiothoracic Surgery, Kobe Children’s Hospital, Kobe, Japan

Accepted for publication March 27, 2001.

Address reprint requests to Dr Oshima, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama, 930-0194, Japan
e-mail: oshima{at}ms.toyama-mpu.ac.jp

	Abstract

Top Abstract Introduction Patients and methods Results Comment References

 
Background. Although satisfactory results of corrective surgery for atrioventricular septal defects (AVSDs) with complex lesions such as double-outlet right ventricle (DORV) or atrial isomerism have been reported in recent years, the optimal surgical options for isomerism hearts is still a controversial issue.

Methods. We performed anatomically corrective repair on 13 children with balanced forms of complete AVSDs and associated major cardiac anomalies. Eight of the 13 patients had atrial isomerism (right in 1, left in 7), 5 of whom had DORV. Four others had DORV with trisomy 21, and 1 had tetralogy of Fallot. Atrial septation for isomerism with the placement of an additional prosthesis was performed on 4 patients.

Results. Two hospital deaths and one late death occurred only in the isomerism group. Three reoperations were required solely in the left isomerism group: one replacement of the valved external conduit concomitantly with reconstruction of the left ventricular outflow obstruction, one mitral valve replacement for severe regurgitation of left atrioventricular valve, and one relief of progressing left ventricular outflow obstruction.

Conclusions. The results of anatomically corrective surgery for AVSDs with major associated cardiac anomalies in the nonisomerism group were excellent. The optimal surgical options for isomerism heart, however, remain a controversial issue.

	Introduction

Top Abstract Introduction Patients and methods Results Comment References

 
Over the past several years, the procedures for repairing isolated complete atrioventricular septal defects (AVSDs) have been improved, resulting in a higher success rate. In addition, satisfactory results of corrective surgery for these defects with complex lesions such as double-outlet right ventricle (DORV) or atrial isomerism have also been reported [1–4]. However, some patients with DORV have not been good candidates for biventricular repair because the interventricular communication has no extension to the aorta. For our patients with isomerisms, a Fontan operation was preferred rather than a complicated atrial septation with interventricular rerouting. This report describes our experience with anatomically corrective repair of complex complete AVSDs.

	Patients and methods

Top Abstract Introduction Patients and methods Results Comment References

 
Patient population
Thirteen patients with balanced forms of complete AVSDs and associated major cardiac anomalies underwent anatomically corrective repair between January 1988 and February 2000 at Kobe Children’s Hospital. Eight of the 13 patients had atrial isomerism (right in 1, left in 7) with DORV in 5 and associated cardiac anomalies in 3. Four of the other patients had DORV with trisomy 21, and 1 had tetralogy of Fallot. Their ages at operation ranged from 5 months to 10 years (median 4.7 years). All but 1 patient had had previous palliative procedures: pulmonary artery banding in 7 (1 with additional right modified Blalock-Taussig shunt due to right pulmonary artery distortion by banding, and 2 with concomitant ligations of a patent ductus arteriosus) and systemic-pulmonary artery shunts in 6.

Morphological findings are summarized in Table 1. Seven patients had left atrial isomerism, and 1 had right isomerism. The anomalies of systemic and pulmonary venous return in the isomerism group are shown in Figure 1. All 8 patients with isomerism had a common atrium. Four of the 7 patients with left isomerism had azygos or hemiazygos continuation. Bilateral superior venae cavae (SVC) were seen in 9 patients, both isomerism and nonisomerism. Of these, the left SVC connected directly to the left-sided atrium in 7 isomerism patients and communicated through the coronary sinus to the right atrium in the other 2. Direct drainage of hepatic veins to the atrium was present in 5 patients with left isomerism. One patient had cor triatriatum and totally unroofed coronary sinus with anomalous left SVC. All pulmonary veins drained to a common chamber connecting directly to the right-sided atrium in 1 patient. In another patient, the right pulmonary veins formed a common vein and connected to the right-sided atrium. These 2 patients had a common pulmonary venous stenosis at the opening site into the atrium. Dextrocardia was seen in 2 patients, both of whom had an L-loop configuration. Among the 3 patients with pulmonary atresia, 1 had a nonconfluent pulmonary artery and the other 2 had coarctation of the pulmonary artery [5]. Pulmonary stenosis was present in 2 patients. A ventricular septal defect (VSD) was more or less committed to the aorta in all 9 patients with DORV. An apical muscular VSD was present in the 1 with tetralogy of Fallot. The AVSDs were classified as Rastelli type A in 2, type B in 1, and type C in 10. Double orifice mitral valve (DOMV) was associated with type C in 2. One of them also had straddling chordae from the right ventricle to the posterior common leaflet. The left-sided single papillary muscle (parachute mitral valve) was seen in 1 patient with type B. The preoperative Doppler echocardiographic study revealed severe to moderate AV valve incompetence in 3 patients. The aorta arose completely from the right ventricle in 8 of the patients with DORV, and 50% to 75% of the aorta was over the right ventricle in 1 patient with DORV without pulmonary stenosis. The preoperative electric cardiograms presented sinus rhythms in all patients. Intraoperative epicardial mapping to identify the sinus node was not performed in any cases with left isomerism.

View larger version (33K): [in this window] [in a new window]   Fig 1. Systemic and pulmonary venous return in isomerism hearts. (LV = left ventricle; HV = hepatic vein.)

Intraventricular rerouting
The one-patch technique was performed on the first 2 patients and 1 with an intermediate form of AVSD, and the two-patch technique was performed on the other 10 patients.

AV valve repair
The left-sided superior and inferior leaflets of the common AV valve were attached to the crest of the interventricular septal patch and were approximated with interrupted sutures in 10 patients. Two of the 3 patients with DOMV had the left-sided cleft left open. Another patient with straddling mitral valve had closure of the cleft and concomitant chordal replacement with expanded polytetrafluoroethylene (ePTFE) sutures. Repair of the cleft together with Reed annuloplasty was performed on 1 patient with DORV and trisomy 21. A severely incompetent right-sided AV valve was replaced by a prosthetic valve during the initial repair in the patient with right isomerism.

DORV
Construction of a tunnel connecting the left ventricle to the aorta was accomplished through a combined atrial and right ventricular approach in 7 patients, and solely through atrial approach in 2 with trisomy 21. The VSD cephalad was enlarged in 2 patients. The abnormal muscular bar at the subaortic portion between the VSD and the aortic valve was resected in 2 patients with isomerism. An interventricular tunnel was constructed using a Dacron patch in 5, and an ePTFE patch in the remaining 4.

Right ventricular outflow reconstruction
The site of the previously performed pulmonary artery banding was enlarged by an autologous pericardial patch. The vertical right ventriculotomy was enlarged by patching in 2 patients. One patient with pulmonary stenosis received a right ventricular-pulmonary artery transannular patch with a monocusp. Extracardiac valved conduit repair was performed on 2 of the 3 patients with pulmonary atresia. Another received external conduit repair with a monocuspid pericardial roll. The patient with tetralogy of Fallot required a right ventricular-pulmonary artery transannular patch with a monocusp. In the 2 patients with pulmonary atresia, the pulmonary coarctation was repaired using a pericardial patch.

Isomerism
An anomalous left SVC connecting to the left-sided atrium was repaired in 5 patients. In 4 of these patients, the pericardial or ePTFE baffle was constructed along the roof of the left atrium to the plane of the atrial septum. Another patient with hemiazygos continuation had "a floating ePTFE graft" to establish the left SVC to right atrium continuity avoiding the left ventricular inflow obstruction because the position of the orifice of the left SVC was unusual, being between the left inferior pulmonary vein and the mitral orifice (Fig 2). Two other patients had ligation of the left SVC. The interatrial septum was reconstructed with a pericardial patch in all but 2 of the patients undergoing the one-patch method. In the 2 patients with obstructed anomalous pulmonary venous drainage, the pulmonary venous opening to the atrium was enlarged by resection of the atrial septum.

View larger version (45K): [in this window] [in a new window]   Fig 2. The orifice of the left SVC with hemiazygos continuation was between the orifice of the left pulmonary vein and the mitrial orifice. "A floating ePTFE graft" was established in the left SVC to right atrium continuity to avoid the left ventricular inflow obstruction. (LSVC = left superior vena cava; RSVC = right superior vena cava; RPV = right pulmonary veins; HV = hepatic vein; ePTFE = expanded polytetrafluoroethylene.)

	Results

Top Abstract Introduction Patients and methods Results Comment References

Patients were followed up from 2 months to 12 years (average 4.4 years). There was one late death in the isomerism group. The patient died suddenly at home 2 months after the operation, although the postoperative course had been uneventful in the hospital, and the postoperative catheterization disclosed few abnormal findings. Only the echocardiography showed mild to moderate mitral incompetence. None of the postoperative electrocardiograms had presented significant arrhythmia. Three reoperations were performed among the 5 survivors with left isomerism. One patient (patient 2) had a replacement of the valved external conduit by a monocuspid pericardial roll together with relief of the left ventricular outflow obstruction (LVOTO) by an ePTFE patch 7 years postoperatively. The second (patient 3), who had had moderate to severe AV valve incompetence preoperatively, underwent a prosthetic valve replacement of a severely incompetent mitral valve 22 months postoperatively. In the third (patient 8), the progressing LVOTO was relieved by fibromuscular resection through the aortic root 8 months after the repair of intermediate AVSD (Rastelli type A) and associated lesions. Recent echocardiographic examinations revealed LVOTO in 1 and moderate mitral incompetence in 5. Postoperative electrocardiograms had not shown any significant arrhythmia in any survivors at any stage of the follow-up. Currently 6 of the survivors are in New York Heart Association functional class I, and four are in class II.

	Comment

Top Abstract Introduction Patients and methods Results Comment References

 
Recently satisfactory results of corrective surgery for complete AVSDs with complex cardiac lesions such as DORV or atrial isomerism have been reported [1–4]. In Kobe Children’s Hospital, DORV has been observed in 14% of the patients who underwent corrective repair of complete AVSDs. One-third of the candidates for definitive repair among the isomerism patients received corrective surgery, the goal of which involves both anatomical and physiological correction of these complex anomalies. However, it is often difficult to accomplish anatomically corrected biventricular repair of isomerism hearts. In addition, patients with right-isomerism hearts are rarely good candidates for biventricular repair because of the difficulty in creating two AV valves and the presence of systemic and pulmonary venous return anomalies, even though two ventricles each have an adequate volume. An alternative procedure for repairing these isomerism hearts is a modified Fontan operation. Recently, the short-term and mid-term success rates of this functional repair have increased [6]. Hence, longer follow-ups and accumulation of a larger number of patients are needed before the anatomically corrective repair can be adopted as the preferred option for the isomerism heart; discussion has focused on anatomically corrective repair of complex complete AVSDs with DORV and atrial isomerism.

Left superior vena cava
The anomalous left SVC connecting to the left upper corner of the left atrium is usually associated with the absence of either an innominate vein or all or part of the coronary sinus. This condition, referred to as unroofed coronary sinus syndrome, is usually associated with other complex anomalies including AVSD, cor triatriatum, and atrial isomerism. The orifice of the left SVC is usually posterior and superior to the entrance of the left atrial appendage, and superior and anterior to the left superior pulmonary vein. The anomalous caval return, therefore, is diverted into the right atrium through the tunnel constructed along the left atrial roof [7]. In 1 of our isomerism patients, the position of the orifice of the left SVC with hemiazygos continuation was between the left lower pulmonary vein and mitral orifice. Tunnel reconstruction of the normal coronary sinus pathway, the so-called "reroofing" procedure [8], might leave the potential for obstruction of the left pulmonary veins and mitral valve. We therefore constructed the new pathway between the left SVC orifice and atrial septum using a floating graft. This method may be useful in elder patients, although obstruction of the graft is always a possibility. As an alternative procedure, ligation of the anomalous left SVC, based on an intraoperative occlusion test with measurement of proximal venous pressure, has been recommended, however, isomerism hearts are rarely able to undergo ligation of the left SVC.

Interventricular rerouting
In our series, a tunnel repair was accomplished in all patients with DORV. Two of these patients, both of whom had isomerism and a noncommitted VSD, required resection of the abnormal muscle between the VSD and aorta. It is difficult to perform a satisfactory rerouting from the left ventricle to the aorta when the ventriculoarterial discordant connections of the isomerism heart or noncommitted VSD with situs inversus are present [1]. In these patients, a biventricular repair that converts the right ventricle to systemic ventricle or a Fontan repair should be considered. Even though the interventricular communication extends to a subaortic position, it is sometimes necessary to enlarge the VSD cephalad [1]. The configuration of the interventricular patch is also a matter of importance for preventing LVOTO. A patch in the shape of a comma is usually sutured to create the interventricular rerouting. We have intentionally used a fan-shaped patch of either Dacron or ePTFE, the latter of which has become more prevalent recently due to some concern over the potential for the Dacron patch to shrink or cause hypertrophy. Development of LVOTO after the initial repair of complete forms of AVSDs associated with DORV using an interventricular patch of Dacron was seen in patient 2.

Subaortic stenosis after the initial repair of AVSDs without VA discordance is also well known. The morphologic features of AVSDs, in which the LVOT is narrowed and elongated because of the scooped-out septal crest, promote potential subaortic stenosis. Recently the concept of lifting the superior leaflet or augmentation of the left superior bridging leaflet to prevent LVOTO has been reported [9, 10]. Muscular resection is often performed, but it has recurrence potential in patients with an abnormally small angle between the plane of the outlet septum and the crest of the septum [11]. A modified Konno procedure can be effective in relieving LVOTO caused by the deviated outlet septum. In our series, patient 8 with intermediate AVSD (Rastelli type A) was treated by fibromuscular resection through the aortic root 8 months after the initial surgery. Complete relief of LVOTO was difficult for such a small patient. A combination of lifting the superior leaflet (conversion to Rastelli type C) and myectomy may be a viable option.

AV valve repair
Except for the initial two patients, all patients with complete forms of AVSDs underwent a two-patch procedure in which it is much easier to consider the configuration of the patch and to repair the AV valve than in a one-patch procedure. The morphologic complexity of the left AV valve is a risk factor associated with hospital mortality or residual left AV valve regurgitation. DOMV and single left-sided papillary muscle were shown to be risk factors [12]. The use of left AV valve annuloplasty or leaving the cleft open might be beneficial. We accomplished repairing the AV valve with DOMV in 2 patients: 1 had annuloplasty and artificial chorda due to associated straddling of the left AV valve, and 1 had the cleft left open. After the initial AVSD repair, 1 patient (patient 3) required mitral valve replacement because of severe mitral incompetence. Three patients with left isomerism have been followed up for moderate left AV valve incompetence associated with LVOTO. Although in 2 of them relief of LVOTO has actually provided improvement of symptoms, the need for mitral valve reconstruction and reoperation for LVOTO in the future is inevitable.

Atrial septation
When an intraventricular tunnel construction from the left ventricle to the aorta is not possible in patients with ventriculoarterial discordance, an atrial switching and rerouting with atrial baffles are considered viable options [1]; an arterial switching and Fontan operations are also potential alternative surgical procedures. The presence of anomalous systemic and pulmonary venous return also requires complicated procedures such as the above-mentioned atrial switching or rerouting with atrial baffles [4].

Although anatomically corrected biventricular repair is considered an ideal option in a group of patients with isomerism hearts, early and late results after this surgery are still not satisfactory. Severe right ventricular failure could cause early mortality. Myocardial damage during the long cardiopulmonary bypass, large-sized interventricular baffles, incompetent valved external conduit, and the incompetent right-sided AV valve may be the primary causes of right ventricular failure. On the other hand, high pulmonary resistance or severe AV valve incompetence could be limiting factors in completing a Fontan operation, which is considered an alternative surgical procedure. Additionally, the long-term results, including quality of life attained with functional repair, are matters of concern. Deciding which is the optimal option for treating these complex lesions has to wait for further accumulation of early and late results of a variety of these surgical procedures. We continue to perform a biventricular repair on the patients who have balanced, formed AVSDs and the ventriculoarterial discordant connections with isomerism. We intend to do corrective surgery, including an artificial valve replacement, for patients with severe AV valve incompetence. When noncommitted VSDs are present, we consider it advisable to do a biventricular repair that converts the right ventricle to systemic ventricle or a Fontan procedure. Accurate recognition of isomeric hearts and the precise repair in accordance with their specific anatomy are indispensable for the improvement of surgical results.

	References

Top Abstract Introduction Patients and methods Results Comment References

 

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4. Hirooka K., Yagihara T., Kishimoto H., et al. Biventricular repair in cardiac isomerism. A report of seventeen cases. J Thorac Cardiovasc Surg 1995;109:530-535.[Abstract/Free Full Text]
5. Zevallos-Giampietri E.A., Thelmo W.L., Anderson V.M. Coarctation of the left pulmonary artery: effects on the pulmonary vasculature of infants. Pediatric Cardiology 1997;18:376-380.[Medline]
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7. Sand M.E., McGrath L.B., Pacifico A.D., et al. Repair of left superior vena cava entering the left atrium. Ann Thorac Surg 1986;42:560-564.[Abstract/Free Full Text]
8. Quaegebeur J., Kirklin J.W., Pacifico A.D., et al. Surgical experience with unroofed coronary sinus. Ann Thorac Surg 1978;27:418-425.[Abstract/Free Full Text]
9. Starr A., Hovaguimian H. Surgical repair of subaortic stenosis in atrioventricular canal defects. J Thorac Cardiovasc Surg 1994;108:373-376.[Abstract/Free Full Text]
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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Yoshihiro Oshima Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Oshima, Y. Articles by Ootaki, Y. Search for Related Content PubMed PubMed Citation Articles by Oshima, Y. Articles by Ootaki, Y. Related Collections Congenital - cyanotic