Ann Thorac Surg 2000;70:1711-1712
© 2000 The Society of Thoracic Surgeons
Case report
Unbalanced atrioventricular septal defect with parachute valve
Woong-Han Kim, MDa,
Taek-Yeon Lee, MDa,
Soo Cheol Kim, MDa,
Soo Jin Kim, MDa,
Young Tak Lee, MDa
a Divisions of Cardiothoracic Surgery and Pediatric Cardiology, Sejong Heart Institute, Sejong General Hospital, Puchon City, South Korea
Address reprint requests to Dr Kim, Division of Cardiothoracic Surgery, Sejong Heart Institute, Sejong General Hospital, 91-121 Sosa Bon 2-dong, Sosa-ku, Puchon City, Kyonggi-do 422-232 South Korea
e-mail: woonghan{at}thrunet.com
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Abstract
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A 5-month-old male patient presented with right-dominant unbalanced atrioventricular septal defect and left-sided parachute valve, and underwent successful biventricular repair. Because of the presence of a small left ventricle, left atrium, and a single left papillary muscle, an additional orifice was created in the left-sided atrioventricular valve with artificial partitioning of the right-sided atrioventricular valve. There was no evidence of mitral stenosis or regurgitation on follow-up echocardiography.
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Introduction
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There has been a dramatic improvement in the results of correcting complete atrioventricular septal defects (AVSDs) in the last decade. In AVSD, the atrioventricular valve may be positioned unequally over the right or left ventricle with variable degrees of associated ventricular hypoplasia (unbalanced AVSD). There are no proven guidelines for deciding between biventricular repair or univentricular palliation in unbalanced AVSD. In this case, we describe the successful biventricular repair of a right-dominant unbalanced AVSD with parachute valve.
A 5-month-old male patient, weighing 4.7 kg, associated with Down’s syndrome was admitted to the hospital because of tachypnea. Echocardiographic findings were compatible for right-dominant unbalanced AVSD with partitioned atrioventricular valve. Left-sided atrioventricular valve was small and supported by a single papillary muscle, and the left atrium and left ventricle were hypoplastic. The valve area ratio of left to right atrioventricular valves was 28% to 72%. There was a large atrial and ventricular septal defect with malalignment of each septum.
Surgical correction was performed. An associated patent ductus arteriosus (PDA) was closed before performing a cardiopulmonary bypass. Operative assessment documented a hypoplastic left ventricle and a parachute deformity of the left-sided atrioventricular valve. The left atrium was diminutive because of a leftward malalignment of the interatrial septum. The defect was repaired by using a divided one patch (bovine pericardium) technique (Fig 1). The ventricular septal defect was closed with interrupted pledget-supported and continuous 6-0 polypropylene sutures first. Then the divided portion of the patch was sewn to the right-sided leaflet with interrupted pledget-supported 6-0 polypropylene sutures. The remaining portion of the patch was used to partition the atrial septal defect with running 6-0 polypropylene sutures. The superior portion of the right-sided leaflet was sutured to the patch to prevent right-sided atrioventricular valve regurgitation. For annular size reduction, the part of the patch to be sutured to the annulus was designed to be slightly smaller. It was possible to increase the left atrial volume by attaching the atrial septal patch more to the right of the original septum after septectomy. As a result, the coronary sinus was drained into the left atrium. To reduce regurgitant flow, reduction annuloplasty of the right-sided valve was performed. Aortic cross-clamp time was 107 minutes and cardiopulmonary bypass time was 228 minutes.
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Fig 1. Schematic presentation of apical four-chamber views and the surgeon’s view of the intraoperative finding and the surgical technique applied in the patient. (A) Apical four-chamber view, preoperatively. (B) Right-dominant unbalanced atrioventricular septal defect. The broken line represents the ventricular septum. (C) Design for patch. A single bovine pericardial patch was carefully tailored to fit the septal defect tightly. (D) View from right chamber. (E) View from left chamber. (F) Apical four-chamber view, postoperatively. (LA = left atrial; LV = left ventricle; RA = right atrial; RV = right ventricle.)
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The patient was separated from bypass without significant difficulty. At intraoperative transesophageal echocardiography (TEE), there was no left-sided atrioventricular valve stenosis or grade I regurgitation, no right-sided atrioventricular valve stenosis or regurgitation, but there was poor left ventricular contractility, which resulted from afterload mismatch. The patient was transferred to the intensive care unit with the sternum left open. The sternum was closed 2 days after surgery and the remaining postoperative course was uneventful. At daily follow-up, a rapid increase in the left ventricular mass was observed on echocardiogram. Left ventricular posterior thickness increased from 4.5 mm at 1 day postoperatively to 6.9 mm at 9 days postoperatively. Ejection fraction was depressed 1 to 2 days postoperatively (36% to 45%) but improved to 57% by 9 days postoperatively. We observed the increase in left ventricle dimensions with reversal of septal bowing and an increase in left ventricle long dimension (Fig 2).
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Fig 2. Echocardiographic views. (A) Preoperative apical four-chamber views demonstrating right-dominant unbalanced atrioventricular septal defect with left-sided parachute valve. (B) Postoperatively apical four-chamber view shows the increase in left atrial size by newly formed right-sided atrial patch and small remnant of original interatrial septal tissue (IAS). Both original left-sided atrioventricular valve and additional left-sided atrioventricular valve (originally right-sided atrioventricular valve) were well demonstrated. (IVS = intraventricular septum.)
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The patient was discharged 18 days after surgery. At the 3-month follow-up, the patient was in good health with appropriate growth, increased left ventricular mass, and good left ventricular contractility; therefore, cardiac medication was discontinued. At the 17-month follow-up, the patient was clinically healthy with dual mitral orifice showing no evidence of stenosis or regurgitation (Table 1).
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Comment
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In unbalanced cases of complete AVSD, there are no proved guidelines for deciding between biventricular repair or univentricular palliation. Although biventricular repair is the choice of surgical option, it is a difficult decision because of the formidable technical challenges facing the surgeon. The importance of the potential left ventricular volume by the septal shift model in right-dominant unbalanced AVSD was emphasized by van Son and coworkers [1]. We agree that the preoperative true left ventricular size may be misleading because loading conditions may also play a role. The determinant of successful biventricular repair of right-dominant unbalanced AVSD appears to be related more to the adequacy of the size of the left ventricular inlet than to the size of the left ventricle if physiologic criteria of biventricular repair are permitted. Cohen and coworkers [2] emphasized the importance of the relative sizes of the atrioventricular valve areas in the outcome of patients with unbalanced AVSD. In our opinion, surgical manipulation is a factor of the increase in size of atrioventricular valve areas. As in this patient, we believe that biventricular repair of an unbalanced AVSD can be further expanded with some technical modification.
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References
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Van Son J.A., Phoon C.K., Silverman N.H., Haas G.S. Predicting feasibility of biventricular repair of right-dominant unbalanced atrioventricular canal. Ann Thorac Surg 1997;63:1657-1663.[Abstract/Free Full Text]
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Cohen M.S., Jacobs M.L., Weinberg P.M., Rychik J. Morphometric analysis of unbalanced common atrioventricular canal using two-dimensional echocardiography. J Am Coll Cardiol 1996;28:1017-1023.[Abstract]
Accepted for publication January 31, 2000.
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Abstract
Introduction
