Ann Thorac Surg 2002;74:592-593
© 2002 The Society of Thoracic Surgeons
Case report
Accessory fibrous band causing anterior mitral valve leaflet restriction
Irmien Vlassak, MDa,
Muhammed Mumtaz, MDb,
Gosta Pettersson, MDb,
James D. Thomas, MD*a
a Department of Cardiology, The Cleveland Clinic Foundation, Cleveland, Ohio, USA
b Department of Cardiothoracic Surgery, The Cleveland Clinic Foundation, Cleveland, Ohio, USA
Accepted for publication February 4, 2002.
* Address reprint requests to Dr Thomas, Cardiology/Desk F15, 9500 Euclid Ave, Cleveland, OH 44195 USA
e-mail: thomasj{at}ccf.org
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Abstract
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A 20-year-old woman with neurofibromatosis (type I), presented with heart failure due to severe mitral regurgitation. Echocardiography and surgery revealed an accessory fibrous band causing anterior mitral valve leaflet restriction. Resection of the fibrous band and correction of the mitral valve using the accessory fibrous band was performed. The further postoperative course was uncomplicated.
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Introduction
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Congenital mitral regurgitation is classified according to the four anatomic components of the mitral valve as follows: leaflets, commissures, chordae tendinae, and papillary muscle [1]. Leaflet abnormalities include cleft leaflet, leaflet hypoplasia or agenesis, and accessory valvular tissue. Subvalvular lesions include chordal agenesis or retraction, elongation of chordae, and papillary muscle lesions. Annular dilation and deformation may also occur either as a primary or secondary process. We report a rare cause of severe mitral regurgitation (MR) due to an accessory fibrous band from the interatrial septum restricting anterior mitral leaflet (AML) motion treated successfully with mitral valve repair.
A 20-year-old mentally retarded woman with a history of asthma, anemia, and neurofibromatosis (type I) but no prior documented murmur, presented with class III heart failure. Clinical exam revealed an afebrile, tachypneic patient. She was tachycardic (115 bpm) and blood pressure was 86/68 mm Hg. Her skin was dry with a few "café au lait" spots. By lung auscultation there were fine basal crackles. Heart auscultation revealed a new 4/6 pansystolic murmur, maximal at the apex and radiating to the upper chest and the back. An additional third heart sound was noted. Chest roentgenogram revealed a cardiomegaly and signs of pulmonary congestion. Electrocardiogram showed sinus tachycardia and right atrial enlargement. Two-dimensional transthoracic and transesophageal echocardiogram showed a mildly dilated left ventricle. Left and right ventricular function was preserved. There was moderate tricuspid regurgitation with severe pulmonary hypertension (estimated right systolic ventricular pressure = 97 mm Hg). The mitral valve leaflets were mildly thickened with failure of leaflet coaptation due to retraction of the AML by an abnormal linear band attached to the atrial side of the midportion of the AML and the midportion of the interatrial septum (Fig 1).
Color Doppler echocardiography revealed severe MR with a regurgitant orifice greater than 1 cm2. The operation was performed under cardiopulmonary bypass with normothermia and cold blood cardioplegia. The mitral valve was exposed through the atrial septum by opening the right atrium. Exploration confirmed the echo findings, revealing a fibrous band going from the anterior border of the fossa ovalis down to the edge of the midportion of the AML (Fig 2).
After resecting the fibrous band, however, there was still mild prolapse of the AML due to poor chordal support as well as annular dilatation. Two sections of secondary chordae were moved to the edge of the AML to support the midportion. In addition, the resected fibrous band was used to construct a new chord from the midportion of the AML down to the posteromedial papillary muscle. Finally, annuloplasty was performed with a Cosgrove-annuloplasty ring size 28 (Baxter Healthcare Corporation, Irvine, CA). The valve was tested and found competent. The tricuspid annuloplasty was performed with one suture placed at the commissures between the anterior and lateral leaflets. Post-pump transesophageal echocardiography demonstrated a competent mitral valve and mild-to-moderate tricuspid insufficiency. The postoperative course was uneventful. At 6 months follow-up, the patient remained asymptomatic and there was no audible murmur by physical exam.
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Fig 1. Transesophageal echocardiography, four-chamber view; accessory band going from the interatrial septum to the anterior mitral leaflet. (LA = left atrium; LV = left ventricle.)
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Fig 2. Intraoperative finding of the accessory fibrous band (arrow) going from the anterior border of the fossa ovalis down to the edge of the midportion of the anterior mitral leaflet.
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Comment
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Primary congenital mitral valve abnormalities have different possible features. They may be complex, affecting one or multiple anatomic components of the mitral valve thereby leading to mitral insufficiency or stenosis. Very few cases of congenital heart disease associated with neurofibromatosis (type I) appear in the literature, although an increased incidence has been suggested [2, 3]. Congenital lesions reported include right ventricular outflow tract obstruction, atrial and ventricular septal defects, coarctation of the aorta (thoracic and abdominal), and extracardiac tumors invading the heart [3, 4]. Our case is an unusual cause of mitral valve insufficiency caused by an accessory fibrous band restricting the AML motion, most likely a coincidental finding in a patient with neurofibromatosis (type I). The fibrous band must be congenital, but interestingly no murmur was noted on physical exams performed when the patient was younger. Perhaps with cardiac growth, the band became more restrictive of AML motion leading to MR. A vicious cycle then ensued with MR leading to atrial enlargement, subsequently even more restriction and regurgitation, and ultimately congestive heart failure. Of particular interest in our case is the surgical correction of the mitral valve. The pulling of the fibrous band had created a wide unsupported mid-portion of the AML. In addition to two sections of secondary chordae, the accessory fibrous band causing the MR was used to construct a new chord for the AML, resulting in good support of the AML. A Cosgrove-annuloplasty ring was added to reduce and stabilize the annulus size, resolving the MR. A perfect immediate result was obtained.
This case is not only unique with regard to etiology of the MR but also a good illustration of the validity and applicability of the basic principles and tools for mitral valve repair. The anomalous fibrous band was used to buttress the AML in a manner similar to Gore-Tex (W.L. Gore & Assoc, Flagstaff, AZ) artificial chordae [5]. Although the tensile strength of the fibrous band appears sufficient to repair in the short run, long-term follow-up will be necessary to confirm this.
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References
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- Carpentier A., Branchini B., Cour J.C., et al. Congenital malformations of the mitral valve in children. Pathology and surgical treatment. J Thorac Cardiovasc Surg 1976;72:854-866.[Abstract]
- Aughenbaugh G.L. Thoracic manifestations of neurocutaneous diseases. Radiol Clin North Am 1984;22:741-756.[Medline]
- Neiman H.L., Mena E., Hold J.F., et al. Neurofibromatosis and congenital heart disease. Am J Roentgenol Radium Ther Nucl Med 1974;122:146-149.[Medline]
- Noubani H., Poon E., Cooper R.S., et al. Neurofibromatosis with cardiac involvement. Pediatr Cardiol 1997;18:156-158.[Medline]
- David T.E., Armstrong S., Sun Z. Replacement of chordae tendinae with Gore-Tex sutures: a ten-year experience. J Heart Valve Dis 1996;5:352-355.[Medline]
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Abstract
Introduction
