Mitral Valve Aneurysm as a Sequela of Infective Endocarditis : Review of Pathologic Findings in Japanese Cases

: Mitral valve aneurysm is defined as a localized protrusion of the valve with a different radius from that of the remaining portion of the valve. The medical records and pathological findings of seven patients with mitral valve aneurysm [aged 48-69 years (mean 64), 4 males] and the pathological findings of other 29 Japanese cases were reviewed. All seven patients were diagnosed pathologically as infective endocarditis, but two patients had no documentation of clinical symptoms suggestive of infective endocarditis (latent infective endocarditis). The underlying lesion of the heart was aortic valve disease and/or fibrosal degeneration of the mitral valve. Only 29 of 36 Japanese case reports stated a precise description of the valve pathology. Of these 29 cases, 23 were associated with infective endocarditis, two with rheumatic valvular disease with fusion and/or shrinkage of the chordae tendineae, three with mitral valve prolapse or myxomatous degeneration of the mitral valve, and one with aortitis syndrome. Neovascularization was described in eight cases. Neovascularization with thick wall should be considered as post-inflammatory vascularization. This review indicates that patients with latent infective endocarditis and mitral valve aneurysm should be considered as potential candidates for valve surgery.