Pathological aspects of explanted homograft mitral valve.

BACKGROUND

Homograft mitral valve replacement is an alternative therapeutic approach to prosthetic or bioprosthetic valve replacement. The present paper documents the pathological changes of explanted homograft mitral valve.

METHODS

We examined six explanted homograft mitral valves, which were taken out 6 weeks to 60 months following valve replacement procedure. Gross examination of the specimens was done, and representative sections were evaluated using haematoxylin-eosin, Masson's trichrome, Verhoeff's van Gieson and von Kossa stains.

RESULTS

On gross examination, the valves showed leaflet calcification and chordal rupture at the tip of the papillary muscles in three cases each. Microscopically, the valve leaflets appeared as aneucleated structures with loss of endocardial lining and lack of nuclear details. The collagenous skeleton was largely preserved. The papillary muscles underwent coagulative necrosis and lacked significant inflammatory infiltrate. One case had a few macrophages at the periphery of myonecrosis, while two cases revealed focal foreign body giant cell reaction. Foci of dystrophic calcification within the areas of myonecrosis were present in three cases.

CONCLUSION

Homograft mitral valve undergoes degenerative changes in the recipient, some of which can be attributed to ischaemia.