Ann Thorac Surg 1997;63:1452-1455
© 1997 The Society of Thoracic Surgeons
Case Report
Multiple-Leaflet Mitral Valve as a Rare Cause of Congenital Mitral Insufficiency
Afksendiyos Kalangos, MD, PhD,
Ingrid Oberhansli, MD,
Gregory Khatchatourian, MD,
Beat Friedli, MD,
Bernard Faidutti, MD
Clinics for Cardiovascular Surgery and Pediatric Cardiology, University Cantonal Hospital of Geneva, Geneva, Switzerland
Accepted for publication November 19, 1996.
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Abstract
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A rare case of congenital mitral insufficiency characterized by six well-demarcated leaflets of mitral valve and annular dilatation is reported. At operation, the mitral valve was successfully repaired by resection of the posterior median leaflet with subsequent annular plication, closure of unusual valvular tissue divisions, and ring annuloplasty.
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Introduction
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Congenital malformations of the mitral valve (MV) are rare. Their mostly complex and diverse features and frequent association with other congenital lesions usually render their diagnosis and description difficult before operation [1]. Mitral valve reconstruction seems to be the best solution, which offers a valuable alternative to prosthetic valve replacement [1]. We report a case of successful MV repair for congenital mitral insufficiency due to an unusual multiple-leaflet MV configuration.
An 8-year-old girl known to have weakness, failure to thrive, and exercise intolerance since early childhood was sent from Benin to our institution for evaluation of severe mitral and tricuspid insufficiency and New York Heart Association stage IV cardiac insufficiency with marked peripheral edema and ascites. Cardiac disease had been diagnosed only at the age of 3 years in a local hospital, and she was from then on treated with digoxin, diuretics, and antibiotics. A rheumatic origin was suspected in her country of origin which, however, was not supported by a precise detailed personal history.
On physical examination at age 8 years, she had an apical impulse in the sixth intercostal space of the midaxial line, a narrowly split second heart sound with accentuation of the pulmonary component, and a grade 4/6 mitral and tricuspid regurgitant murmur irradiating into both sides of the thorax and the back. Laboratory findings excluded rheumatic heart disease, bacterial endocarditis, and an inflammatory myocardial or myopericardial disease. Chest roentgenograms showed severe global cardiomegaly with a cardiothoracic ratio of 0.8 and signs of pulmonary congestion. Electrocardiography showed sinus rhythm, right-axis deviation, and biatrial and biventricular dilation. Two-dimensional transthoracic and transesophageal echocardiography disclosed important dilatation of all cavities with dominance of the left chambers, pulmonary hypertension, and severe diastolic and systolic dysfunction of both ventricles. Both atrioventricular valves were thin and mobile. First two-dimensional transthoracic echocardiography and then transesophageal echocardiography revealed that the MV had an unusually festooned aspect (Fig 1A
). Behind the anterior tricuspid leaflet an echodense homogeneous mass resembling a thrombus was suspected. Doppler evaluation showed severe mitral and tricuspid valve insufficiency. Cardiac catheterization with angiography revealed no coronary abnormality but confirmed severe mitral insufficiency with pulmonary hypertension.
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Fig 1. . (A) Two-dimensional transthoracic echocardiogram in a short-axis view of the left ventricle at the mitral valve level presents the diastolic appearance of a festooned but mobile mitral valve. Arrows indicate six commissural separations. (B) Two-dimensional transthoracic echocardiogram showing in a four-chamber apical view the repaired mitral valve during diastole. Mitral valve leaflets show unrestricted opening. Arrows indicate the Carpentier-Edwards annuloplasty ring. (La = left atrium; Lv = left ventricle.)
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Operation was conducted under cardiopulmonary bypass with moderate hypothermia (28°C) and cold potassium cardioplegia. The MV was exposed directly via the left atrium. Its analysis revealed six well-demarcated leaflets with a severely dilated annulus. There was an anterior leaflet at the usual place. Two leaflets were located laterally and the other three posteriorly, and all represented three-fourths of the MV circumference (Fig 2A). All leaflets were thin, but the commissural edges of the three posterior leaflets (PLs) were moderately thickened and rolled up. Commissural chordae between the anterior and both lateral leaflets were attached to a hypoplastic anterior and posterior papillary muscle. The other commissural chordae tendineae originated directly from the trabeculae carneae of the posterior left ventricular myocardium. At operation, this condition was corrected by resection of the median PL and subsequent annular plication in the corresponding posterior area using 2-0 Cardioflon (Petus Pharm Lab, Bobigny, France) sutures. Thereafter a new posterior common leaflet was constructed by suturing the commissural edges of the two resting PLs between them and to the adjacent lateral leaflets with separate 6/0 monofilament stitches (Fig 2B). Chordae attached to the free edges of these corresponding commissures were resected to prevent restriction of the new PL. Marginal chordae were preserved to avoid a prolapse of the restored PL. A Carpentier-Edwards annuloplasty ring, size 26, was selected by measuring the anterior leaflet area using obturators for remodeling the annulus, reinforcing the repair, and avoiding further dilation of the annulus. Saline solution was injected into the ventricular cavity through the valve and demonstrated a satisfactory repair with a good symmetric line of apposition between leaflets and absence of leaks.
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Fig 2. . (A) The prerepair mitral valve configuration was characterized by an anterior leaflet (AL), two lateral leaflets (LL), two posterolateral leaflets (PLL), and one posteromedian leaflet (PML). (B) The technique of repair consisted of remodeling the annulus with a Carpentier-Edwards ring (1) after annular plication in the area of the resected median posterior leaflet, subsequent suture of the free edges between posterolateral leaflets (PLL) (2), and closure of valvular divisions between lateral (LL) and posterolateral leaflets.
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The tricuspid valve was exposed through a right atriotomy. Its analysis revealed an anterior leaflet with an indentation of 4 mm at its midline and a normal septal leaflet and PL. The annulus was dilated. Tricuspid insufficiency was considered as functional, and no annuloplasty was performed. The right ventricular echogenic mass was found to be a hypertrophied trabecula. There was no thrombus in the right ventricle. Postoperative transthoracic and transesophageal echocardiography showed a good coaptation between two MV leaflets without any residual leaks.
Pathologic examination of the resected median PL and of left and right ventricular myocardial biopsy specimens showed normal histologic structures. The postoperative course was uneventful. Repeat echocardiographic controls up to 6 months postoperatively showed a mobile MV (Fig 1B
) without any residual leak or stenosis, a tricuspid valve with only mild insufficiency, and gradual resolve of ventricular dilatation and pulmonary hypertension.
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Comment
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Primary congenital MV abnormalities are identified according to the four anatomic components of the valve [2]. The most common lesion in congenital MV disturbance is an abnormality of the papillary muscles, followed by the involvement of leaflets, commissures, and chordae tendineae. In our case, although MV malformation comprises abnormalities of each of these components, the presence of multiple valvular tissue divisions, which can be considered as clefts, was the main anomaly. Clefts are often confused with enlargement of the normal indentations of the PL secondary to annular dilatation [3]. These indentations can give to the PL a three- or rarely five-scalloped appearance [4]. In our case, two indentations were located at the free margin of the median PL and thus the other vertical divisions affecting the posterior valvular tissue were regarded as true clefts. Primary chordae attached to these so-called true clefts with a fanlike very wide insertion provided an appearance that was identical to that seen in normal commissural areas. In our case, mitral insufficiency resulted from MV annular dilatation that caused enlargement of all commissural areas and a poor coaptation line between adjacent leaflets. Annular dilatation and deformation is almost always present in all types of MV incompetence whether or not it is associated with functional abnormalities of the leaflets. Annular dilatation was the only detected malformation in 17% of cases of congenital mitral insufficiency, and a prosthetic ring annuloplasty was necessary in 60% of them [1].
Compared with mechanical or bioprosthetic valve replacement in children, the reconstructive operation remains the better option, with the well-established advantages of lower mortality, lower morbidity, avoidance of anticoagulation, and hence improved quality of life [1, 5]. As was disclosed in our case by the festooned aspect of the MV, two-dimensional echocardiography is the only method available to reliably diagnose multiple valvular tissue divisions. Although valvular reconstruction can be considered a technique that corrects the function rather than the anatomy of the valve, in our case the function was corrected by converting multiple-leaflet MV anatomy to two-leaflet configuration.
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Footnotes
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Address reprint requests to Dr Kalangos, Clinic for Cardiovascular Surgery, University Cantonal Hospital of Geneva, 24, rue Micheli-du-Crest, 1211 Geneva 14, Switzerland.
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References
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- Carpentier A, Branchini B, Cour JC, et al. Congenital malformations of the mitral valve in children. Pathology and surgical treatment. J Thorac Cardiovasc Surg 1976;72:854–66.[Abstract]
- Davachi F, Moller JH, Edwards JE. Diseases of mitral valve in infancy. An anatomic analysis of 55 cases. Circulation 1971;43:565–79.[Abstract/Free Full Text]
- Carpentier A. Surgical anatomy and management of the mitral components of atrioventricular canal defects. In: Anderson RH, Shinebourne EA, eds. Pediatric cardiology. London: Churchill Livingstone, 1978:477–90.
- Ranganathan N, Lam JHC, Wigle ED, Silver MD. Morphology of the human mitral valve. II. The valve leaflets. Circulation 1970;41:459–67.[Abstract/Free Full Text]
- Ben Ameur Y, Ben Ameur N, Drissa H, Fehri W, Abid F. L'insuffisance mitrale congénitale. Diagnostic, pronostic et traitement. Ann Cardiol Angéiol 1995;44:165–70.
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Abstract
Introduction
