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Morphologic features of the normal and abnormal mitral valve
Insights
Severe cardiac dysfunction in 1,010 patients revealed rheumatic mitral stenosis (MS) in 43% and non-rheumatic mitral regurgitation (MR) in 16%. Mitral valve prolapse was the primary cause of MR in patients over 30 without aortic valve disease.
Area of Science:
- Cardiology
- Valvular Heart Disease
- Pathology
Background:
- Mitral valve disease, including mitral stenosis (MS) and mitral regurgitation (MR), significantly contributes to cardiac dysfunction.
- Understanding the etiology and prevalence of these conditions is crucial for patient management and treatment strategies.
Purpose of the Study:
- To review the anatomic and functional features of normal and abnormal mitral valves.
- To determine the prevalence and causes of mitral stenosis and mitral regurgitation in patients with severe cardiac dysfunction.
Main Methods:
- Analysis of necropsy data from 1,010 patients with severe cardiac dysfunction (NYHA Class III or IV) due to primary valvular heart disease.
- Review of operatively excised mitral valves from patients with pure mitral regurgitation.
Main Results:
- Mitral stenosis (MS) was present in 43% of patients, predominantly of rheumatic origin.
- Pure mitral regurgitation (MR) was found in 16% of patients. Mitral valve prolapse was the most common cause of MR in patients over 30 without aortic valve dysfunction, while rheumatic heart disease was more common when aortic valve disease was present.
- Mitral annular calcification in individuals over 65 is often associated with atherosclerosis and may cause mild MR or MS.
Conclusions:
- Rheumatic heart disease is a primary cause of mitral stenosis.
- Mitral valve prolapse is a significant cause of mitral regurgitation, particularly in older adults without coexisting aortic valve disease.
- Mitral annular calcification in the elderly may represent a manifestation of atherosclerosis.
Abstract:
Anatomic and functional features of the normal and abnormal mitral valve are reviewed. Of 1,010 personally studied necropsy patients with severe (functional class III or IV, New York Heart Association) cardiac dysfunction from primary valvular heart disease, 434 (43%) had mitral stenosis (MS) with or without mitral regurgitation (MR): unassociated with aortic valve stenosis or regurgitation or with tricuspid valve stenosis in 189 (44%) patients, and associated with aortic stenosis in 152 (35%), with pure (no element of stenosis) aortic regurgitation in 65 (15%) patients, and with tricuspid valve stenosis with or without aortic valve stenosis in 28 (6%) patients. The origin of MS was rheumatic in all 434 patients. Of the 1,010 necropsy patients, 165 (16%) had pure MR (papillary muscle dysfunction excluded): unassociated with aortic valve stenosis or regurgitation or with tricuspid valve stenosis in 97 (59%) patients, and associated with pure aortic regurgitation in 45 (27%) and with aortic valve stenosis in 23 (14%) patients. When associated with dysfunction of the aortic valve, pure MR was usually rheumatic in origin, but when unassociated with aortic valve dysfunction it was usually nonrheumatic in origin. Review of operatively excised mitral valves in patients with pure MR unassociated with aortic valve dysfunction disclosed mitral valve prolapse (most likely an inherent congenital defect) as the most common cause of MR. Excluding the patients with MR from coronary heart disease (papillary muscle dysfunction), mitral prolapse was the cause of MR in 60 (88%) of the other 68 patients, and a rheumatic origin was responsible in only 3 of the 68 patients, all 68 of whom were greater than 30 years of age. Mitral anular calcification in persons aged greater than 65 years is usually associated with calcific deposits in the aortic valve cusps and in the coronary arteries. Because calcium in each of these 3 sites is common in older individuals residing in the Western World, it is most reasonable to view mitral anular calcification in older individuals as a manifestation of atherosclerosis. Mitral anular calcium appears to be extremely uncommon in persons with total serum cholesterol levels less than 150 mg/dl. Mitral anular calcium may produce mild MR and, if the deposits are heavy enough, MS.