Application of homografts in clinical surgery

Aortic freehand homografts have been used since 1962 and are still our preferred method of treatment. They are centrally flowing and are consequently nonobstructive and give rise to neither emboli nor turbulence. They do, however, undergo a slow process of degeneration, giving plenty of time for an elective low risk second operation. An additional advantage is that they can be used in children. Various methods of valve preparation and storage have been used, but there is no clear evidence that one particular method is superior. The position of the homograft in the heart does have a bearing on its function, with the valve persisting longer in the low-pressure right heart chambers. Long-term results indicate that the unmounted homograft in the aortic area gives better results than currently used bioprostheses and in the right ventricular outflow tract there is no comparable valve. Studies of the viability of the various valve components and also their immunological significance should help to improve the long term durability of the homograft valve.