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Floppy mitral valve chordae tendineae: histopathologic alterations
P B Baker1, G Bansal, H Boudoulas
1Department of Pathology, Ohio State University College of Medicine, Columbus.
Abstract:
Pathologic studies of floppy or myxomatous mitral valves have focused primarily on changes in the valve cusps, with little attention given to the chordae tendineae. In a systematic study of the histopathology of floppy mitral valve chordae tendineae, 128 nonruptured chordae from 8 severely regurgitant floppy mitral valves were compared to 152 chordae from 10 normal control mitral valves and to 152 chordae from 8 control mitral valves with severe regurgitation due to ischemic heart disease. Collagen alterations were observed in 2% of normal mitral valve chordae and 3% of control regurgitant mitral valve chordae compared to 38% of floppy mitral valve chordae. Moderate or severe acid mucopolysaccharide accumulation was observed in 2% of normal mitral valve chordae and 3% of control regurgitant mitral valve chordae compared to 39% of floppy mitral valve chordae. Nonuniform histopathologic alterations, rare in normal and control regurgitant mitral valve chordae tendineae, were frequent in floppy mitral valve chordae tendineae (p less than 0.001). Histopathologic alterations provide the basis for abnormal physical properties previously demonstrated in floppy mitral valve chordae tendineae and may predispose to chordal elongation and rupture.
Insights
Histopathologic alterations in floppy mitral valve chordae tendineae, including collagen changes and acid mucopolysaccharide accumulation, are common. These findings explain abnormal physical properties and may lead to chordal rupture.
Area of Science:
- Cardiovascular Pathology
- Histopathology
- Biomedical Engineering
Background:
- Pathologic studies of floppy mitral valves predominantly focus on valve cusps, neglecting chordae tendineae.
- The structural integrity of chordae tendineae is crucial for normal valve function.
Purpose of the Study:
- To systematically investigate the histopathology of chordae tendineae in floppy mitral valves.
- To compare these alterations with normal controls and valves with ischemic regurgitation.
Main Methods:
- Histopathologic analysis of 128 nonruptured chordae from 8 floppy mitral valves.
- Comparison with 152 chordae from 10 normal controls and 152 chordae from 8 ischemic heart disease controls.
Main Results:
- Significant differences in collagen alterations and acid mucopolysaccharide accumulation in floppy mitral valve chordae compared to controls (38% vs. 2-3%).
- Nonuniform histopathologic alterations were frequent in floppy mitral valve chordae (p < 0.001).
Conclusions:
- Histopathologic changes in floppy mitral valve chordae tendineae provide a basis for their abnormal physical properties.
- These alterations may predispose the chordae to elongation and rupture, contributing to severe mitral regurgitation.