Interact CardioVasc Thorac Surg 2008;7:1199-1200. doi:10.1510/icvts.2008.187179
© 2008 European Association of Cardio-Thoracic Surgery
Severe mitral regurgitation due to cardiac amyloidosis – a rare reason for ruptured chordae
Hiroyuki Nishi,
Masataka Mitsuno,
Masaaki Ryomoto and
Yuji Miyamoto*
Department of Cardiovascular Surgery, Hyogo College of Medicine, 1-1, Mukogawa-cho, Nishinomiya, Hyogo, 661-8501, Japan
Received 27 June 2008;
received in revised form 5 August 2008;
accepted 8 August 2008
Corresponding author. Tel.: +81-798-45-6852; fax: +81-798-45-6853.
E-mail address: y-miyamo{at}hyo-med.ac.jp (Y. Miyamoto).
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Abstract
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Although cardiac amyloidosis is often associated with mitral valve disease due to amyloid deposits, severe mitral valve regurgitation in a patient with systemic amyloidosis is uncommon. We report a 38-year-old man with severe mitral valve regurgitation due to ruptured chordae. He underwent mitral valve repair and both leaflets of mitral valve appeared normal except for ruptured chordae. Postoperative histological results revealed the presence of the amyloid deposit in the mitral valve and ruptured chordae. The amyloid deposit might be a cause of ruptured chordae, which is a rare reason for mitral valve regurgitation in a patient with cardiac amyloidosis.
Key Words: Mitral regurgitation; Amyloidosis; Ruptured chordae
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1. Introduction
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Cardiac amyloidosis is generally recognized as associated with a thickened mitral valve resulting from amyloid deposits and is considered a main reason for mitral valve dysfunction [1]. This report presents a patient with severe mitral valve regurgitation because of a ruptured chordae that led to mitral valve repair. Although the pathological results showed amyloid deposits in the mitral valve and chordae, they were not thickened and appeared normal macroscopically.
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2. Case report
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A 38-year-old man, diagnosed with systemic amyloid A-related amyloidosis by rectal and gastric biopsy two years previously, showed a grade 3/6 systolic murmur at the apex. Initially, he did not have any sign of heart failure. An echocardiogram revealed severe mitral regurgitation because of P3 prolapse. The mitral valve was not thickened. Although his left ventricular ejection fraction was preserved, left ventricular dimension was increased. Right heart pressure and coronary artery were normal on cardiac catheterization.
The patient underwent mitral valve repair with quadrangular resection of the P3 lesion and the implantation of a 28 mm Cosgrove Ring (Edwards Lifesciences, CA). While there was a ruptured chordae on the medial posterior leaflet, the other parts of posterior and anterior leaflets were not thickened and appeared normal. During the surgical procedure, mitral valve (P3 lesion and ruptured chordae) and right heart myocardial biopsy specimens were obtained. A postoperative echocardiogram showed the successful repair of the mitral valve. The patient was discharged without any problems.
Postoperative histological results revealed the presence of an inhomogeneous deposit in the right heart myocardium, as well as in the mitral valve and ruptured chordae. These deposits reacted positively to Congo Red staining. Immunohistochemical staining revealed a positive Amyloid A component – AA type amyloid. These amyloid deposits had spread towards the ruptured chordae (Fig. 1).
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Fig. 1. Postoperative histological results revealed the presence of an inhomogeneous deposit in the mitral valve, as well as ruptured chordae (a, d). These deposits reacted positively to Congo Red staining. Immunohistochemical staining revealed a positive amyloid A component. (a–c) Chordae, (d–f) mitral valve, (a, d) HE stain, (b, e) immunohistochemical stain (positive amyloid A protein), (c, f) Congo Red stain.
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3. Discussion
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Despite the well-known histologic involvement of cardiac valves in amyloidosis, the onset of clinical and hemodynamic signs of valvular dysfunction is rare [1]. Amyloid deposition may cause cardiovascular dysfunction in a variety of ways and several reports have described stenotic valvular lesions [2, 3]. Although there are many patients with cardiac amyloidosis accompanied with mild or moderate MR [4], severe mitral valve regurgitation in a patient with systemic amyloidosis is uncommon, with just two cases reported [5, 6]. One case showed extensive amyloid infiltration of the left ventricular myocardium and mitral papillary muscles. The other revealed a reduction of mitral valve motion caused by a stiff mitral valve. Cardiac function in both cases was severely depressed as a consequence of amyloid deposition. However, the reason for mitral regurgitation in the case presented here was a ruptured chordae; with histological findings revealing amyloid deposits in both the mitral valve and chordae. Despite the presence of amyloid deposits on the mitral valve, motion was normal and the valve itself was not thickened. The amyloid deposit might have been a cause of the ruptured chordae, a rare reason for mitral valve regurgitation in a patient with cardiac amyloidosis. Masugata et al. [4] mentioned the possibility of less elasticity producing fragility and weakness of mitral valve leaflets in patients with cardiac amyloidosis. Hence this change in the physical properties of a mitral valve might affect chordal stress.
In patients with amyloidosis, cardiac involvement in the form of an infiltrative cardiomyopathy is common with frequent development of congestive heart failure [1]. There are two types of amyloidosis – one associated with inflammatory conditions (AA amyloid), the other with plasma cell dyscrasia (AL amyloid). AA amyloid is derived from the immunochemically related acute phase serum reactant SAA, whereas AL amyloid is derived from immunoglobulin light chains [7]. In AL amyloidosis, cardiac amyloidosis is often the principal cause of death. On the other hand, significant cardiac involvement is uncommon in AA amyloidosis. The current case was diagnosed as having AA amyloid in his rectal and gastric areas, as well as in myocardium and the mitral valve. We postulated, that this was the main reason he did not initially develop congestive heart failure.
This case illustrated a possible new mechanism for mitral regurgitation in a patient with cardiac amyloidosis. The outcome of surgery was acceptable. As the patient was young and the amyloid deposits in the mitral valve had already been proven, we will need to apply long-term follow-up of his cardiac and mitral valve functions, including monitoring valve thickness.
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References
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Abstract
1. Introduction