[Viability of new valvular homografts. Myth or reality?]

Use in cardiac surgery of aortic homografts as a valvular substitute is old and was specially developed in France by F. Fontan. In fact, these first allografts were non-viable and the results, in aortic position, were not better than current bioprosthesis. Renewed interest is related to the important notion of "viability" allowed by an immediate procurement (organ donors), preparation in nutrient medium RPMI with low doses of antibiotics and final storage at -196 degrees C (cryopreservation). We have reviewed our initial experience concerning 32 implanted homografts in children either in reconstruction of the right ventricular outflow tract (in many forms of congenital heart disease) or in aortic position. No mortality was observed. The only failure was due to an initial sizing mistake leading to an aortic valve replacement at 13 months. No late deterioration (mean follow-up: 12.5 months) was detected by echocardiography. These results seem to confirm other larger series (as O'Brien's, Brisbane, Australia). Biologic, histological and immunological assessments of "viable" homografts are discussed. The limits of the technique are reported.