Ann Thorac Surg 2002;73:1302-1303
© 2002 The Society of Thoracic Surgeons
Case report
Mitral annular aneurysm resulting from subaortic muscle resection
Manabu Watanabe, MD*a,
Yorikazu Harada, MDa,
Takamasa Takeuchi, MDa,
Gengi Satomi, MDb,
Satoshi Yasukouchi, MDb
a Department of Cardiovascular Surgery Nagano Children’s Hospital, Nagano, Japan
b Department of Cardiology, Nagano Children’s Hospital, Nagano, Japan
Accepted for publication August 14, 2001.
* Address reprint requests to Dr Watanabe, Department of Cardiovascular Surgery, Nagano Children’s Hospital, 3100 Toyoshina, Toyoshina-machi, Minamiazumi-gun, Nagano 1399-8288, Japan
e-mail: dookuman{at}beige.ocn.ne.jp
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Abstract
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We present a case of mitral annular aneurysm as a very rare complication developing soon after the surgical relief of subaortic stenosis. The cause of the aneurysm was considered to be the disruption of aorto-mitral intervalvular fibrosa at the initial operation. The surgical repair was successfully performed without compromising either aortic or mitral valvular functions. The preoperative transesophageal echocardiography was useful in delineating the precise anatomic features of this rare complication.
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Introduction
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Mitral annular aneurysm is very rare complication after the surgical relief of subaortic stenosis (SAS). It could compromise both mitral and aortic valvular functions by disrupting the integrity of aortomitral intervalvular fibrosa, and could develop massive intracardiac shunt by its rupture, so that an urgent surgical intervention is deemed to be necessary. We report a successful surgical repair of progressive mitral annular aneurysm originating from the aortomitral intervalvular fibrosa complicated after the first surgical repair of SAS.
A 2-month-old girl was referred to our hospital with the diagnosis of perimembranous ventricular septal defect and pulmonary hypertension. Echocardiography demonstrated a large perimembranous ventricular septal defect with posteriorly deviated infundibular septum, which caused SAS. The cardiac catheterization showed a pulmonary to systemic flow ratio of 4.5 and pulmonary arterial systolic pressure of 60 mm Hg. At the age of 4 months, she had the first intracardiac repair of the ventricular septal defect and SAS. The ventricular septal defect was closed with a bovine pericardial patch through the right atrium. The posteriorly deviated infundibular septum was resected through the aortic valve annulus, of which the resected area extended from beneath the nadir of the right coronary cusp to the area adjacent to the left fibrous trigone. She had a good postoperative course and was discharged. At the age of 9 months, she was referred to us for a giant mitral annular aneurysm protruding into the left atrium. Transesophageal echocardiography clearly demonstrated the giant mitral annular aneurysm, sized 17 x 18 mm, at the aortomitral intervalvular fibrosa, the size of which seemed to be rapidly progressing during the 5 months’ interval after the initial operation (Fig 1).
In spite of this disruption of intervalvular fibrosa, both aortic and mitral valvular competencies were well preserved. At the age of 9 months, she had the second operation. The left atrium was entered by transatrial septal approach, and the mitral valve structure was found to be intact. A large aneurysm originated from the aortomitral intervalvular fibrosa, approximately 3 to 5 mm apart from the anterolateral commissure of the mitral valve. From the transaortic view, a fistula of 5 mm in diameter was identified at the junction between noncoronary and left coronary cusps. An exploring probe could enter the aneurysm through this fistula, and a part of the wall of the aneurysm was composed of the interatrial septum. The fistula tract was closed from the left atrial side to avoid distortion of the aortic annular geometry.
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Fig 1. Transesophageal echocardiography clearly demonstrated the neck of the giant mitral annular aneurysm at the aortomitral intervalvular fibrosa. The aneurysm was expanded during systole (A) compared with diastole (B). Transesophageal echocardiography also demonstrated that both aortic and mitral valves were intact. (AAo = ascending aorta; AML = anterior mitral leaflet; LA = left atrium.)
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After most of the aneurysmal wall was resected, aorto-mitral intervalvular continuity was reestablished by approximating the mitral annulus and aortic subvalvular tissue, which was reinforced by a bovine pericardial patch. Postoperative echocardiography demonstrated well-reconstructed aortomitral continuity without compromising each valvular function, and the patient was discharged 10 days after the operation with good postoperative course.
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Comment
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There are several case reports describing various types of congenital or acquired submitral annular aneurysms [1–3], but none of them reported one originating from aortomitral intervalvular fibrosa as an unusual complication after the surgical relief of SAS. We present here a case report of postoperative mitral annular aneurysm. The mitral annular aneurysm disrupts the aortomitral fibrous continuity and jeopardizes the integrity of both aortic and mitral valve; moreover, the systolic expansion of this aneurysm into the left atrium may compromise hemodynamics by impeding atrial filling and has a chance of rupturing at any moment [4]. The aortomitral intervalvular fibrosa is composed of the right, left, and interventricular fibrous trigone, and the area that was resected at the initial operation ranged from beneath the nadir of the right coronary cusp to the left fibrous trigone. The injury to the left fibrous trigone itself or adjacent muscle could cause the disruption of aortomitral fibrous continuity, aggravated by the pressure gradient between the left atrium and left ventricle during the postoperative course, which facilitated expansion of the aneurysm into the interatrial septum in our case.
Surgical success depends on the precise preoperative identification of the position of the neck of the aneurysm within the fibrous skeleton. Transesophageal echocardiography could detect the intervalvular aneurysm more effectively, characterize the cavitary lesions in the aortic root, and guide appropriate surgical intervention [5, 6]. In this case, preoperative transesophageal echocardiography was very useful in delineating the precise spatial relationship of the aneurysmal orifice to both aortic and mitral valves. The intimate relationship of the orifice to the aortomitral fibrous continuity makes primary closure of the orifice difficult because this fibrous structure maintains the integrity of both aortic and mitral valvular function. Kruithoff and colleagues [4] reported an unsuccessful case of intervalvular aneurysm by primary patch closure, which resulted in severe aortic and mitral regurgitation. In our case, the primary direct closure of the orifice with several buttress sutures reinforced with bovine pericardial strips through the remnant tissue was possible as there was 3- to 5-mm distance between the neck of the aneurysm and the mitral annulus. The postoperative echocardiography demonstrates a well-reconstructed aortomitral continuity with uncompromised valvular function 7 months after the second operation.
In conclusion, we experienced a very rare complication, which led to successful surgical repair of mitral annular aneurysm at the aortomitral intervalvular fibrosa disrupted by resecting the infundibular muscle to relieve SAS. The precise delineation of the anatomy of the mitral annular aneurysm by transesophageal echocardiography is mandatory for planning a successful surgical repair.
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References
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Beckerling C.H., Gibb B.H., Houghton H.G., Le Roux B.T. Left ventricular aneurysm. Thorax 1969;24:173-175.[Abstract/Free Full Text]
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Wolpowitz A., Arman B., Barnard M.S., Barnard C.N. Annular subvalvular idiopathic left ventricular aneurysms in the black African. Ann Thorac Surg 1979;27:350-355.[Abstract]
-
Antunes M.J. Submitral left ventricular aneurysms. Correction by a new transatrial approach. J Thorac Cardiovasc Surg 1987;94:241-245.[Abstract]
-
Kruithoff W.A., Akl B.F., Blacky A.R. Surgical repair of an anterior mitral subvalvular aneurysm. Ann Thorac Surg 1995;59:1001-1003.[Abstract/Free Full Text]
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Essop M.R., Skoularigis J., Sareli P. Transesophageal echocardiography in congenital submitral aneurysm. Am J Cardiol 1993;72:481-483.[Medline]
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Afridi I., Apostolidou M.A., Saad R.M., Zoghbi W.A. Pseudoaneurysms of the mitral-aortic intervalvular fibrosa: dynamic characterization using transesophageal echocardiographic and Doppler techniques. J Am Coll Cardiol 1995;25:137-145.[Abstract]
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Abstract
Introduction
