Eur J Cardiothorac Surg 2003;23:1071-1073
© 2003 Elsevier Science NL
Accessory mitral valve tissue associated with situs inversus in an elderly patient
Peter Lemkea,
Ali Civeleka,
Roland Brandtb,
Matthias Rotha*
a Department of Thoracic and Cardiovascular Surgery, Kerckhoff Clinic Foundation, Benekestrasse 2–8, 61231 Bad Nauheim, Germany
b Department of Cardiology, Kerckhoff Clinic Foundation, Benekestrasse 2–8, 61231 Bad Nauheim, Germany
Received 27 November 2002;
received in revised form 25 January 2003;
accepted 3 February 2003.
* Corresponding author. Tel.: +49-6032-996-2502; fax: +49-6032-996-2567
e-mail: matthias.roth{at}kerckhoff.med.uni-giessen.de
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Abstract
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We report an unusual case of accessory mitral valve tissue associated with a situs inversus and missing obstruction of the left ventricular outflow tract. To our knowledge our patient is the only elderly patient with an accessory mitral valve with associated situs inversus undergoing surgical resection. The report emphasizes direct cardioscopy through the aortic annulus allowing precise excision of the abnormal tissue.
Key Words: Accessory mitral valve • Situs inversus • Cardioscopy
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1. Introduction
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Accessory mitral valve tissue (AMV) is a rare disease that can lead to subaortic valve obstruction and it frequently includes an association with other congenital cardiac anomalies. Seventy eight cases have been reported in the literature since McLean et al. [1] first described this disease in 1963. Among these 78 patients, 49 had associated congenital heart diseases. We found 11 elderly patients with AMV, which in five patients was associated with a cardiac anomaly. Two young patients with an additional situs inversus were specified, but no elderly patient with a combination of AMV and situs inversus has been characterized so far in the literature. We report herein a male patient who had AMV associated with a situs inversus but no left ventricular outflow tract obstruction undergoing mass removal assisted by direct cardioscopy.
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2. Case report
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A 49-year-old man was referred to our hospital due to recurring cardiac arrhythmia. Six months ago he had a posterior myocardial infarction with subsequent balloon angioplasty of the right coronary artery. Physical examination revealed a 3/6 systolic ejection murmur and an arrhythmic cardiac frequency. The long time electrocardiogram showed complex ventricular extrasystoly and sinus arrhythmia with a frequency ranging from 37 to 123/min. Coronary angiography showed an 80% stenosis of the obtuse marginal artery, and a situs inversus. Echocardiographic examination revealed a situs inversus viscero atrialis and a tumor-like abnormal echogenic mass in the vicinity of the anterior leaflet of the mitral valve. The tissue was connected to the posteromedial papillary muscle by an elongated chorda and prolapsing through the native aortic valve during systole (Figs. 1a,b)
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Fig. 1. (a) Transesophageal echocardiography demonstrating an accessory mitral leaflet in subaortic position (68°). (b) Transesophageal echocardiography showing the accessory mitral leaflet prolapsing through the non-coronary cusp of the native aortic valve (115° view).
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The patient underwent cardiac surgery using cardiopulmonary bypass with moderate hypothermia. After aortic crossclamping and delivery of cold blood cardioplegia, the obtuse marginal branch was demonstrated and a venous graft bypass was performed. Afterwards the ascending aorta was opened and cardioscopy accomplished. The aortic valve and the annulus appeared normal. On the ventricular side at the basis of the anterior mitral leaflet we found accessory tissue attached to the papillary muscle with a single chorda (Fig. 2)
. The tissue was excised and the aortotomy closed. The postoperative course was uneventful, and the patient was discharged in good condition on postoperative day 10. Histological examination showed characteristic valve tissue with focal degenerative myxoid changes.
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Fig. 2. Cardioscopic view through the aortic valve showing the elevated accessory mitral valve leaflet in the left ventricle.
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3. Comment
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Accessory mitral valve tissue is usually associated with other congenital cardiac anomalies. Most commonly this malformation is associated with ventricular septal defect, transposition of the great arteries, coarctation of the aorta, partial atrioventricular canal, double outlet right ventricle, membranous septal aneurysm or Noonan's syndrome. Usually the patients present signs of left ventricular outflow tract obstruction (LVOTO) [2]. In our case, the accessory mitral valve was associated with an atrio-ventricular and ventriculo-atrial discordance with absence of LVOTO. In the literature we detected another two patients with situs inversus without additional intracardiac anomaly and 14 patients who presented with either mild or absent LVOTO [3–5]. AMV can vary in appearance from ‘amorphous gelatinous tissue’ to a ‘mature duplicate’ of the mitral valve [6]. We found mitral leaflet measuring a 3.4x2.4x0.3 cm with adhesive chordae. Most authors have suggested that accessory mitral valve tissue is the result of an incomplete separation of the mitral valve from the endocardial cushion tissue to the ventricular septum during embryological development [7,8]. AMV has been described in several ways, including sac-like, balloon-like, parachute-like, sail-shaped, leaflet-like, sheet, membranous, or pedunculated [3]. It is frequently attached to one cusp of the normal mitral valve, the chordae tendineae are connected if presented to the posterior papillary muscle, which may lead to a high-pressure gradient between the left ventricle and the aorta [5]. In our case we found a leaflet-like AMV, which was connected with one chorda tendineae to the posteromedial papillary muscle; in the preoperative examinations we found no LVOTO.
Echocardiography is a very important tool to establish the correct preoperative diagnosis. In 1985 Alboliras et al. reported AMV for the first time in the echocardiographic literature [9]. Further on, transesophageal echocardiography precisely delineates the left ventricular outflow tract obstruction and is frequently used as a sole diagnostic tool to assess subaortic stenosis [10].
Several different surgical approaches have been reported for the excision of AMV tissue; aortotomy alone or combined with left atriotomy are the two surgical approaches used most often [3]. In our case we preferred aortotomy for surgical approach in combination with direct cardioscopy. This approach provides an anatomic definition of the outflow tract and may point out rare anomalies. It likewise permits a wider view of the mitral subvalvular apparatus for a precise excision of the abnormal tissue [2].
In this patient surgical intervention was recommended for three reasons although no obstruction of the left ventricular outflow tract was present. First, there was a present indication for coronary bypass operation; second, there is a lower risk of clinical deterioration; and third, the intracardiac tissue could be a tumor (myxoma, papillary fibroelastoma), so that prophylactic resection of the accessory tissue together with the indication to coronary bypass operation represents a straightforward decision. Surgical excision of the AMV was performed in our case because the accessory mitral valve tissue had no orifice and did not appear to support the primary mitral apparatus; if the tissue is an integral to the function of the mitral apparatus, it may be impossible to excise [4].
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References
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- McLean L.D., Culligan J.A., Kane D.J. Subaortic stenosis due to accessory tissue on the mitral valve. J Thorac Cardiovasc Surg 1963;45:382-387.
- Schmid A.C., Zund G., Vogt P., Turina M. Congenital subaortic stenosis by accessory mitral valve tissue, recognition and management. Eur J Cardiothorac Surg 1999;15:542-544.
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- Van Praagh R., Corwin R.D., Dahlquist E.H., Freedom R.M., Mattioli L., Nebesar R.A. Tetralogy of Fallot with severe left ventricular anomalous attachment of the mitral valve to the ventricular septum. Am J Cardiol 1970;26:93-101.[CrossRef][Medline]
- Cremer H., Bechtelsheimer H., Helpap B. Formen und Genese der subvalvulären Aortenstenose. Virchows Arch Pathol Anat 1972;335:123-134.
- Alboliras E.T., Tajik A.J., Puga F.J., Ritter D.G., Seward J.B. Accessory mitral valve tissue in association with discrete subaortic stenosis: a two-dimensional echocardiographic diagnosis. Echocardiography 1985;2:191-195.
- Baneriee A., Kohl T., Silverman N.H. Echocardiographic evaluation of congenital mitral valve anomalies in children. Am J Cardiol 1995;76(17):1284-1291.[CrossRef][Medline]
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Abstract
1. Introduction
