Homograft valves: is degeneration inevitable?

Since the first successful sub-coronary insertion (Ross 1962), the homograft aortic valve has been the favourite amongst many rypes of mechanicai or biological cardiac vaive repiacements ar the National Heart Hospital. Recent srudies on long rerm patient survivai afrer homograft insertion have reveaied excelient results (Bodnar er ai 1979), surpassed oniy by the autotranspianted puimonary valves. (Ross 1967; Ross et ai 1979). Ir is generally accepted that homograft vaives inserred into the aorric position have two major advantages (Ross 1962), they are non-thrombogenic, and (Bodnar et ai 1979) their haemodynamic performance is identicai to that of a normal aortic valve. However, two major disadvanrages are often reported as weii (Ross 1962): difficuities in the coilection, preparation and storage of these vaives, and (Bodnar et ai 1979) the rapid degenerarion which affects. the function of the homograft (Stinson et ai 1977; Anderson and Hancock 1976; Lefrak and Starr 1979). An analysis of the overali performance of the homograft vaive in the aortic posirion has show satisfactory long term resuits (Bodnar et ai 1979). The present work focuses attention on the degeneration of homograft valves in terms of incidence, onser and pattern.