Abstract
In Japan as in the West, the incidence of non-rheumatic valve disease has been increasing. However, the etiological basis of non-rheumatic valve disease remains unclarified.
Material : One-hundred and fifty-one valve specimens surgically resected at the Cardiovascular Institute Hospital (1987-1994) were investigated. The patients were carefully examined by preoperative echocardiogram, and the macroscopic and microscopic findings of each specimen were studied. These cases were divided into pure regurgitation and stenosis-groups based on the echocardiographic findings, and rheumatic and non-rheumatic groups based on the presence or absence of commissural fusion of the valves.
Results : Non-rheumatic valvular disease was present in 79 patients (52.3%). Aortic, mitral and double valve replacements were performed in 49, 36 and 6 patients, respectively. The pure aortic valve regurgitation group consisted of 8 cases of infective endocarditis, 9 cases of valve prolapse, and one case each of aortitis syndrome, Behcet's disease, connective tissue disease, annulo-aortic ectsia, true and dissecting aneurysm of the aorta. Nineteen of the 25 cases in the aortic stenosis group had a bicuspid aortic valve. Thirty-six cases in the pure mitral regurgitation group consisted of 8 cases of infective endocarditis, one case each of hypertrophic cardiomyopathy and ischemic heart disease, 2 cases of patient ductus arteriosus and 24 cases of mitral valve prolapse. Cases of mitral valve prolapse were divided into 4 subgroups : rupture of chordae tendinea (15), absence of chordae (7) (complicated with chordal rupture), looping chordae (5) and idiopathic mitral valve prolapse (4). Post-inflammatory changes were observed in 2 cases of idiopathic mitral valve prolapse.
Conclusions : Predisposing disorders of non-rheumatic valvular disease include bicuspid valve, sclerosis, looping chordae of the mitral valve, absence of chordae and post-inflammatory valvular disease. Looping chordae and absence of chordae may partly involve secondary changes resulting from rupture of the chordae.
