Characterization of Degenerative Mitral Valve Disease: Differences between Fibroelastic Deficiency and Barlow’s Disease

Abstract

Degenerative mitral valve disease causing mitral valve prolapse is the most common cause of primary mitral regurgitation, with two distinct phenotypes generally recognized with some major differences, i.e., fibroelastic deficiency (FED) and Barlow’s disease. The aim of this review was to describe the main histological, clinical and echocardiographic features of patients with FED and Barlow’s disease, highlighting the differences in diagnosis, risk stratification and patient management, but also the still significant gaps in understanding the exact pathophysiology of these two phenotypes.

Varied Extent of Mitral Annular Disjunction Among Cases With Different Phenotypes of Mitral Valve Prolapse

“…In contrast to patient 1, the extent of disjunction in patients 2 and 3 remained less extensive, and dilatation of the left ventricle, left atrium, and mitral annulus were less marked. Inasmuch as fibroelastic deficiency is characterized by deficiency of connective tissue ( 2 ), the lack of pathologic expansion of disjunction seems reasonable.…”

“…Mitral valve prolapse (MVP) involves various underlying processes affecting the papillary muscles, tendinous cords, mitral valve leaflets, and attachment of the mitral valve ( 1 ). MVP is the main functional feature of degenerative mitral valve disease ( 2 ), which involves the following phenotypes ( Central Illustration ). Barlow disease is characterized by billowing of both mitral leaflets with diffuse myxomatous changes, combined with severe dilatation of the annulus.…”

“…Myxomatous thickening of the leaflet is generally restricted to the prolapsed segments, with the rest of the leaflet remaining rather thin and transparent without annular dilatation. The intermediate state between Barlow disease and fibroelastic deficiency disease is called forme fruste ( 2 , 3 ).

Learning Objectives

To recognize the utility of cardiac CT for accurate 3-dimensional evaluation of the extent of disjunction.

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Collagen Fibrillogenesis in the Mitral Valve: It’s a Matter of Compliance

“…In contrast, in FED, the leaflets are thin, and chordae rupture is more common with the regurgitation involving a limited number of segments of a single leaflet. While Barlow's disease and FED are clearly clinically discernable, their histopathology is not as straightforward [23,31]. It has been suggested that these two forms of MR are part of a spectrum of a single mitral valve degenerative disease that can focally affect the valve as in FED or more broadly as in Barlow's disease [31].…”

“…While Barlow's disease and FED are clearly clinically discernable, their histopathology is not as straightforward [23,31]. It has been suggested that these two forms of MR are part of a spectrum of a single mitral valve degenerative disease that can focally affect the valve as in FED or more broadly as in Barlow's disease [31]. In both FED and Barlow's disease, VICs remodel the ECM of both leaflet and chordae as they are responsible for the pathophysiological adaptation process.…”