Summary: This two-part article examines the histologic and morphologic basis for stenotic and purely regurgitant mitral valves. In Part I, conditions producing mitral valve stenosis are reviewed. In over 99% of stenotic mitral valves, the etiology is rheumatic disease. Other rare causes of mitral stenosis include congenitally malformed valves, active infective endocarditis, massive annular calcium, and metabolic or enzymatic abnormalities. In Part II, conditions producing pure mitral regurgitation will be discussed. In contrast to the few causes of mitral stenosis, the causes of pure (no element of stenosis) mitral reguqytation are multiple. Some of the conditions producing pure regurgitation include floppy mitral valves, infective endocarditis, papillary muscle dysfunction, rheumatic disease, and ruptured chordae tendineae.Key words: mitral stenosis, rheumatic heart disease, mitral regurgitation, mitral valve General Concepts of Function and PathologyMitral valve dysfunction can result from structural alterations (congenital or acquired) of the valve or from abnormal function of a structurally normal valve.' From an etiologic standpoint, it is useful to divide mitral valve dysfunction into either stenotic orpurely regurgitant types. Most stenotic mitral valves are associated with clinical evidence (auscultation, Doppler echocardiography, angiography) of some element of regurgitation, but by definition, pure mitral regurgitation has no element of stenosis.' Although clinically and therapeutically useful, knowledge of whether a mitral valve is both stenotic and regurgitant, or which hemodynamic lesion is dominant, is less helpful in estab lishing etiology of the mitral valve dysfunction. Stenotic mitral valves are always anatomically abnormal (fibrous thlckening, calcific deposits, or both) and the causes for stenosis are limited to a few conditions. In contrast, purely regurgitant mitral valves may or may not have some anatomic abnormality, and the causes for pure regurgitation are multiple. With the exception of congenital causes, stenotic mitral valves usually take years to develop, but purely regurgitant mitral valves may develop acutely or chronically. ' 7 In a recent survey of operatively excised cardiac valves3 the mitral valve was the second most frequently excised native cardiac valve. Of 2,980 excised valves (2,566 patients), 1,398 (47%) were mitral. Of the 1,398 excised mitral valves, 1,154 (83%) were classified as stenotic (with or without associated regurgitation) and 244 (17%) were purely regurgitant (Fig. 1). Three additional studiesM have evaluated over 500 operatively excised mitral valves. The functional classification was stenotic in 45%4 to 63%6 and purely regurgitant in 37%6 to 55%?A decline over a 2 1 -year period in the relative frequency of operatively excised stenotic mitral valves versus purely regurgitant mitral valves has recently been reported by Olson and colleagues6 The frequency of excised stenotic mitral valves decreased from 79% in 1965 to 43% in 1985, while the frequency of ex...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.