Ann Thorac Surg 2001;71:501-505
© 2001 The Society of Thoracic Surgeons
Original article: cardiovascular
Left atrial appendage insertion for right ventricular outflow tract reconstruction
Ryo Aeba, MDa,
Toshiyuki Katogi, MDa,
Ichiro Kashima, MDa,
Katsumi Moro, MDa,
Tsutomu Ito, MDa,
Shiaki Kawada, MDa,
Etsuro Takahashi, MDb
a Division of Cardiovascular Surgery, Keio University, Tokyo, Japan
b Department of Pediatrics, Keio University, Tokyo, Japan
Accepted for publication June 5, 2000.
Address reprint requests to Dr Aeba, Division of Cardiovascular Surgery, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan
e-mail: aeba{at}mc.med.keio.ac.jp
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Abstract
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Background. The left atrial appendage (LAA) may serve as an alternative to the pulmonary arterial wall for right ventricular outflow tract (RVOT) reconstruction without an extracardiac conduit.
Methods. Five consecutive patients with pulmonary atresia or severe stenosis underwent corrective (n = 4) or palliative (n = 1) RVOT reconstruction using an LAA insertion. Surgery was performed to treat tetralogy of Fallot, double-outlet right ventricle, or transposition of the great arteries. By inserting the LAA into the obstructed portion, the width of the posterior wall of the RVOT was 20 mm or more. The anterior half of the RVOT was then augmented with pericardial patch.
Results. There were no early or late postoperative deaths, and no major complications (arrhythmias, thrombo-embolic episodes, infective endocarditis, need for reoperation). The postrepair systolic right ventricular-to-systemic arterial pressure ratio was 0.61 ± 0.26. Color Doppler flow mapping revealed that the reconstructed RVOT was nonobstructive and had nonturbulent flow. No thrombus or pseudoneointimal formation was observed in the RVOT.
Conclusions. LAA insertion in the RVOT is an effective alternative to, or adjunct of, direct anastomosis. It offers several advantages, including fewer early and midterm complications and avoiding the use of an extracardiac conduit.
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Introduction
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Although extracardiac conduits have been used in corrective or palliative right ventricular outflow tract (RVOT) reconstruction for complex cardiac lesions with pulmonary atresia or severe stenosis, they have numerous drawbacks. First, these conduits cannot grow and therefore are often outgrown when implanted in early childhood. Second, conduit reconstruction often results in late conduit obstruction caused by host reactions including pseudoneointimal formation, calcification of the conduit itself, valvular calcification, and fibrous tissue proliferation at the proximal and distal anastomoses. In contrast, direct anastomosis may reduce the requirement for reoperation for conduit exchange because the above complications are avoided. Third, placing a conduit in the thorax without causing adverse hemodynamic effects may be difficult, especially in patients with a small thorax or a counterclockwise-rotated heart in which the distance between the right ventriculotomy and the sternum is small. Finally, conduits can become infected, resulting in serious complication. Therefore, RVOT reconstruction using autologous viable tissue would be preferred.
Direct anastomosis of the pulmonary arteriotomy and right ventriculotomy by either sliding the pulmonary arteriotomy [1–3] or turning the pulmonary trunk wall flap inferiorly [4, 5] creates a posterior floor for the pulmonary arterial wall. However, direct anastomosis cannot always create an anastomosis wide enough to be nonobstructive. Therefore, extracardiac conduits still play an important role in RVOT reconstruction in the setting of anatomically unfavorable factors, including distant obstruction and coronary arterial anomalies. In 1990, Barbero-Marcial and associates [6] used a left atrial appendage (LAA) insertion in a patient undergoing repair of a type II truncus arteriosus. Unfortunately, this patient suffered sudden death because of His bundle necrosis 24 hours after the repair, and the potential usefulness of LAA insertion for RVOT reconstruction was not fully examined [7, 8]. The purpose of this study is to review our surgical experience in patients with a variety of cardiac anomalies who underwent corrective or palliative RVOT reconstruction with LAA insertion.
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Patients and methods
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Between June 1996 and June 1999, 5 consecutive patients with congenital heart disease involving distant RVOT obstruction underwent RVOT reconstruction using an LAA insertion rather than an extracardiac conduit at the Keio University Hospital (Table 1). There were 3 females and 2 males, ranging in age at the time of operation from 1.2 to 4.6 years (mean 2.8 ± 1.4 years). All patients had severe RVOT obstruction (atresia in 4 patients and severe stenosis in 1 patient). The underlying cardiac anomalies included tetralogy of Fallot in 2 patients, a double-outlet right ventricle with a subaortic ventricular septal defect (VSD) in 2 patients, and transposition of the great arteries with a VSD in 1 patient. In 1 of the patients with a double-outlet right ventricle with a subaortic VSD (patient 5), the right coronary artery originated from the left coronary artery, crossing anteriorly both the aorta and pulmonary trunk. All patients had previously undergone single or multiple systemic-to-pulmonary arterial shunt(s). The pulmonary arterial cross-section index [9] before surgery ranged from 196 to 334 (mean: 282 ± 54).
All operations were performed with cardiopulmonary bypass, moderate hypothermia, and cardioplegic heart arrest. Four patients underwent partitioning of the ventricular cavity by the creation of a left ventricular outflow tunnel or closure of the VSD. A baffle or patch of expanded polytetrafluoroethylene (Cardiovascular patch; W. L. Gore and Associates Co, Flagstaff, AZ) was tailored and secured with interrupted Dacron-pledgetted horizontal mattress sutures through a right ventriculotomy with concomitant RVOT reconstruction. In 1 patient (patient 3), the VSD was left unclosed because of the presence of a marginally hypoplastic left ventricle. Maximum mobilization of the right and left branch pulmonary arteries was performed in all of the patients. However, RVOT reconstruction using direct anastomosis of the pulmonary arteriotomy and the right ventriculotomy was not feasible because of extended and distant obstructions in 2 patients. The LAA was moved anteriorly for insertion between the pulmonary arteriotomy and the right ventriculotomy, and secured using a 6-0 polypropylene running suture (Fig 1). In 3 patients, mobilization of the inferior rim of the arteriotomy or creation of a pulmonary trunk wall flap allowed for direct anastomosis to the right ventriculotomy. However, the anastomosis width ranged from only 5 to 10 mm. The LAA was moved anteriorly using a 6-0 polypropylene running suture to augment the anastomosis width of the posterior wall between the pulmonary arteriotomy and the right ventriculotomy (Fig 2). The posterior floor of the RVOT, consisting of autologous tissue (the LAA with or without the pulmonary arterial wall), had a width 20 mm or more, which was equivalent to half of the circumference of the reconstructed RVOT. The LAA flap was maximized in the horizontal (transverse) direction, and minimized in the sagittal (longitudinal) direction to avoid undue tension at the anastomotic site. The left branch pulmonary artery was augmented with an autologous free pericardial patch in 3 patients and with the lay-open technique [10] in 1 patient. The LAA suture line to the epicardium was 3 mm or more away from the major branches of the coronary arteries in all of the patients. For the anterior half of the RVOT reconstruction, a mono-valved porcine pericardial patch (Bioprosthese, Polystan, Walgerholm, Denmark) or an autologous pericardial patch was used.
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Fig 1. Operative procedure in patient 3. (Left) The incision is indicated by the dotted line. Direct anastomosis was not feasible because of an extended and distant obstruction. (Right) The posterior wall was reconstructed using only the left atrial appendage.
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Fig 2. Operative procedure in patient 5. (Left) The incision is indicated by the dotted line. Direct anastomosis using the pulmonary arterial wall flap created the posterior wall with the width of only 10 mm. (Right) The posterior wall of the pulmonary trunk extending to the left branch pulmonary artery was augmented by the insertion of the left atrial appendage.
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The follow-up period ranged from 4 months to 3 years, with a mean of 2.0 years. The follow-up was complete in all of the patients. None of the patients received anticoagulation or antiplatelet aggregation therapy.
All data are expressed as the mean ± the standard deviation.
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Results
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The postoperative recovery was uneventful, and perioperative bleeding was less than 150 mL in all of the patients. No myocardial ischemic ST-T changes were observed. There were no early or late postoperative deaths during the follow-up period. In 1 patient (patient 2) whose VSD was not closed, asymptomatic mild congestive heart failure, manifested by cardiomegaly, developed. The VSD in this patient was closed without any complications 2 months after the initial palliative RVOT reconstruction. After discharge from the hospital, all of the patients remained asymptomatic. There were no major complications, including arrhythmias, thrombo-embolic episodes, infective endocarditis, or presence of residual or recurrent lesions requiring reoperation during the follow-up period.
Hemodynamic studies performed after the repair revealed that the systolic right ventricular-to-systemic arterial pressure ratio was 0.61 ± 0.26 and the systolic pressure gradient between the right ventricle and the pulmonary artery was 7 ± 1 mm Hg. Follow-up echocardiography and catheterization were performed in all of the patients. Postoperative and follow-up echocardiography with color Doppler flow mapping revealed that the reconstructed RVOT was nonobstructive and had a nonturbulent flow. The magnitude of pulmonary insufficiency was trivial or mild in all of the patients, including patient 3, in whom a nonvalved autologous pericardial patch was used in the anterior wall of RVOT. Neither thrombus nor pseudoneointimal formation were observed in the RVOT. Angiography demonstrated that the reconstructed RVOT had a smooth posterior wall (Fig 3) and that the LAA was not thrombosed. In addition, there were no abnormal communications between the RVOT and the LAA.
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Fig 3. Follow-up angiography in patient 3 performed 14 months after right ventricular outflow tract reconstruction using the left atrial appendage. (Left) Frontal view; (right) lateral view.
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Comment
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Reconstruction of the posterior floor of the RVOT with a direct anastomosis, rather than with use of an extracardiac conduit, is appealing because of the excellent follow-up results, including a low incidence of the need for reoperation and infectious complications [1, 2]. However, direct anastomosis has several limitations. Specifically, it may not be technically feasible or there may be significant operative bleeding caused by excessive anastomotic tension if the RVOT obstruction is long. Kinking and excessive tension of the right pulmonary artery is of major concern [11]. Superior and posterior movement of the most cranial end of the right ventriculotomy may cause kinking of the left coronary artery. In such situations, insertion of viable autologous tissue, including the LAA and pericardium, between the pulmonary arteriotomy and the right ventriculotomy can avoid these potential complications. Furthermore, insertion of viable tissue may share a number of potential advantages with direct anastomosis over the use of an extracardiac conduit.
The potential complications of LAA insertion include damaging or kinking the coronary arteries. It is important that the LAA suture line to the epicardium be 
3 mm away from the left anterior descending coronary artery and any anomalous coronary arteries crossing the obstructed RVOT. The development of a residual RVOT obstruction is also possible. Because the lesser curvature of the newly constructed RVOT in the sagittal plane is formed by the LAA, even a small protrusion of the LAA into the RVOT lumen may create a significant obstruction. Therefore, the LAA flap should be maximized in the horizontal (transverse) direction and minimized in the sagittal (longitudinal) direction, which should avoid both residual RVOT stenosis and excess tension at the anastomotic site.
It is our institutional policy that direct anastomosis should be the method of choice and that LAA insertion should be used as an alternative in patients in whom direct anastomosis cannot be used and as an adjunctive procedure in patients in whom direct anastomosis can only create a narrow posterior floor. We have performed 59 RVOT reconstructions in the setting of a variety of cardiac biventricular lesions with unrestrictive interventricular communication and RVOT obstruction, including tetralogy of Fallot repair and the Rastelli procedure. LAA insertion was required in only 5 of these patients (8.5%) between June 1996 and June 1999.
Left-sided Blalock-Taussig shunting, which is indicated for treatment of severe hypoplastic pulmonary arteries, often secures the left branch pulmonary artery cranially, and limits mobilization of this artery for subsequent RVOT reconstruction, making direct anastomosis to the right ventriculotomy difficult or impossible. On the other hand, this shunt often expands the LAA and, more importantly, moves the LAA anteriorly by increasing blood return to the left atrium and increasing left atrial volume. Such a situation is the principal indication for the use of LAA insertion. In fact, all of the patients in our series had previously undergone single or multiple systemic-to-pulmonary arterial shunt(s). Of these patients, 4 had previously undergone a left modified Blalock-Taussig shunt.
Atrial wall flaps have been used for rerouting in the atrium, including the Senning operation, repair of a total anomalous pulmonary venous connection of the cardiac type [12], and a total cavopulmonary connection [13]. In this procedure, part of the epicardial surface is exposed to blood, which should result in a unique intramural pressure distribution for the atrial wall. The LAA flap used for repair of the RVOT shares these abnormal dynamics with intraatrial reconstructions using an atrial wall flap, although the pressure or stress on the epicardium of the LAA may be even greater. Another nonphysiologic aspect of the use of an LAA flap in RVOT reconstruction is that a part of the LAA wall is surrounded by suture line. Because the bite of the suture is eventually deep enough to penetrate the LAA wall, contraction of the isolated LAA wall may be absent or independent of the remainder of the atrial wall. Therefore, the behavior of the LAA flap as part of the pulmonary arterial wall should be carefully considered, particularly with respect to growth and thrombosis or pseudoneointimal formation. Although the relatively short length of follow-up in the present study limits our observations, the favorable hemodynamic and morphologic midterm results suggest that there is considerable potential for normal growth of the LAA with appropriate endothelialization of the LAA epicardium.
Although the use of autologous pericardium may also be helpful for reconstruction of the posterior wall of the RVOT, a number of questions exist concerning its use. The growth potential, the incidence of shrinkage, pathologic changes, the effects of glutaraldehyde fixation, and the effects of pediclization of autologous pericardium are unknown. Until these issues are addressed, we believe that the LAA insertion is preferable to autologous pericardium for RVOT reconstruction.
In summary, we have demonstrated that LAA insertion for RVOT reconstruction is an effective alternative to, or adjunct of, direct anastomosis in selected cases. This method may expand the indications for the use of viable autologous tissues.
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References
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Abstract
Introduction
