Ann Thorac Surg 2009;88:1341-1343. doi:10.1016/j.athoracsur.2009.02.057
© 2009 The Society of Thoracic Surgeons
Case Reports
Two-Patch Repair for Atrioventricular Septal Defect With Mitral Aneurysm
Hajime Imura, MD*,
Shun-ichiro Sakamoto, MD,
Yuji Maruyama, MD,
Masami Ochi, MD,
Kazuo Shimizu, MD
Department of Surgery, Division of Cardiovascular Surgery, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
Accepted for publication February 13, 2009.
* Address correspondence to Dr Imura, 1-1-5, Sendagi Bunkyo-ku, Tokyo, 113-8603, Japan (Email: himura{at}nms.ac.jp).
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Abstract
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We experienced an unusual case of partial atrioventricular septal defect in an elderly patient. A preoperative ultrasonic cardiogram revealed the mitral leaflet pouching toward the right atrium and suggested the presence of a ventricular septal defect underneath the atrioventricular valve. The mitral aneurysm was diagnosed as a septal aneurysm on preoperative ultrasonic cardiogram. A crescent-shaped Dacron patch (InterVascular S. A., La Ciotat Cedex, France) was placed beneath the atrioventricular valve to prevent rupture of the mitral aneurysm and support the anterior mitral leaflet by creating a new annulus. We believe that this is the first report describing this type of mitral aneurysm and its surgical repair.
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Introduction
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There are numerous variations in anatomy of the atrioventricular connection in atrioventricular septal defects (AVSDs) [1, 2]. Ultrasonic cardiogram (UCG) is the most common and useful examination to evaluate such structures [3]; however, it does not always provide fine detail or allow for accurate diagnosis of pathology. We present an elderly case of partial AVSD with mitral aneurysm in this report. In the present case, mitral aneurysm restricted an inter-atrial shunt mimicking the appearance of a ventricular septal defect and septal aneurysm in the preoperative UCG. Two-patch repair, which is normally performed for complete AVSD, was appropriate for this pathology.
A 65-year-old woman was referred to our hospital for the surgical treatment of an atrial septal defect (ASD). The UCG showed a primary ASD and a deficient ventricular septum beneath the atrioventricular valve (Fig 1A). This anomaly was diagnosed as the partial AVSD with septal aneurysm, or the complete form of AVSD with extremely limited ventricular shunt through a membranous septal aneurysm. Moderate mitral regurgitation was seen from the cleft and the central region of the mitral valve. Systolic pressure in the pulmonary artery was 38 (approximately 35% of systemic pressure), and the ratio of pulmonary artery flow to systemic flow was 2.6. During the operation, the pathologic anatomy was investigated by way of a right atriotomy under ordinary cardiopulmonary bypass and cardioplegic arrest. The ventricular septum under the atrioventricular valve was protruded, and the anterior half of the tricuspid septal leaflet was absent (Fig 2A). A mitral cleft was seen between the ventricular septum and its free margin. First, we closed this cleft and inserted a tube into the left ventricle. Once the left ventricle was volume loaded, the mitral portion was bulged and tense, whereas the tricuspid portion did not show such changes (Fig 2B). No major cordal support was recognized beneath the bulged mitral leaflet. Thus, we suspected central mitral regurgitation was due to this unsupported mitral leaflet. To exclude the aneurysmal area from a new mitral leaflet and obtain adequate mitral coaptation, we elected to attach a Dacron patch (InterVascular S. A., La Ciotat Cedex, France) beneath the atrioventricular valve. For ASD closure, a strip of Dacron (3-mm wide) was attached to an autologous quadrangular pericardial patch. The Dacron edge was sutured to the atrioventricular valve. Thus, a two-patch repair was carried out. When the pericardial patch was built on the atrioventricular valve, the line of stitches on the mitral valve was determined to exclude the aneurysmal region from the new mitral valve. Because the regurgitation from the new mitral valve was trivial at this point, the ASD was closed with a pericardial patch (Figs 1B and 2C). To minimize tricuspid regurgitation, the accessory anterior leaflet was attached to the patch and covered the anterior septal area. The patient had a good postoperative course. Her UCG showed less than mild mitral and tricuspid regurgitation after 1 year.
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Fig 1. Transesophageal echocardiographic findings of (A) a mitral aneurysm seen on the ventricular septum. (B) Shown after two-patch repair.
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Fig 2. Surgical views through the right atriotomy (A) before repair. (B) Mitral aneurysm apparent with volume loading of the left ventricle. (C) Shown after two-patch repair.
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Comment
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We believe that this is the first report presenting mitral aneurysm, most of which were previously reported as a complication or sequela of endocarditis [4, 5], occurring in an AVSD patient. In the present case, a mitral aneurysm extended toward the right ventricle, mimicking the appearance of ventricular septal defect covered with a membranous tissue in UCG. Therefore, preoperative diagnosis was difficult and problematic. In fact, a previous report contained similar UCG observations, although a different diagnosis was reached [6].
A deficient cordal structure and leaflet malformation are always present in the atrioventricular valve of AVSD [7]. We speculate that aneurysmal change was developed under the condition of high pressure loading to the unsupported area. Although most mitral aneurysms have been reported as complications of endocarditis, the present case was likely due to a different pathology that necessitated a unique surgical procedure. Distinguishing mitral and tricuspid tissues in the atrioventricular valve was difficult. However, once the left ventricle was volume loaded, only the mitral portion of the atrioventricular valve was bulged; thereafter, the mitral and tricuspid areas were easily identified and the aneurysmal portion of the mitral leaflet could be recognized. To determine the size of the Dacron patch (DuPont) and its attachment line on the mitral leaflet, the anterior mitral leaflet had to be bulged.
Although this technique is not normally used for partial AVSD, we attached a Dacron patch underneath the atrioventricular valve to secure the closure of the shunt from the left ventricle, exclude the aneurysmal region from the mitral valve, normalize the height of the atrioventricular valve, and obtain adequate mitral coaptation by pushing back the mitral leaflet to the left side. Because left atrioventricular valve regurgitation is an unresolved problem [8], creation of a new mitral annulus has certain benefits for further mitral surgery. The prosthetic mitral ring can be easily placed on this new annulus without injuring the conduction system. Because the annulus should be sufficiently solid for possible subsequent prosthetic annular ring or valve surgeries, we used a Dacron strip on the pericardial patch for ASD closure.
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References
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Abstract
Introduction
