Composition of surface layers in unfixed autologous fascia lata heart valve grafts. A transmission electron...

Sixty-nine patients underwent aortic valve replacement with frame mounted non-fixated fascia lata grafts. Nine patients still have their fascia lata valve in place after a period of between 9 to 11 years. Fifty-two grafts were available for histo-pathologic examination. The mechanism of valve thickening was studied by transmission electron microscopy (TEM). The major factor contribution to the thickening seems to be a surface accumulation of complex proteins, fibrin and platelets. Within the valvular tissue itself, subcellular degenerative products in cell cytoplasm, the interstitium and in the sub-surface layer also contributed. The thickening never exceeded one fifth of the original thickness of the valve.