Aortic valve and/or aortic root replacement using an aortic homograft

Abstract

Aortic valve replacement using the homograft valve has a special place in the cardiac surgical practice although it has never been widely used, in part due to the lack of tissue donors but also due to the perceived difficulty of the procedure compared with aortic valve replacement using prosthetic devices and concerns regarding homograft valve failure. The principal indication for aortic valve replacement using a homograft aortic valve is for active aortic valve endocarditis (native or prosthetic) with or without perivalvular tissue destruction (abscess cavity, fistula, detachment of the anterior mitral valve leaflet from the aortic annulus). Since the homograft tissue is pliable and adaptable, it can be used to repair defects in complex cases with root destruction. A second interesting application of homograft aortic valve is in the treatment of small aortic root (in which replacement with a small prosthetic valve would produce an unacceptable orifice ratio and ultimately affect long-term outcome) and left ventricular outflow tract obstruction when the homograft aortic valve can be combined to the Konno procedure. Homograft aortic valve can be used in these cases without sacrifying the pulmonary valve to be used as aortic valve substitute (for instance in adolescents and young adults who do not want to undergo a 'two-valve' procedure like the Ross-Konno procedure). The most frequent operation technique is the cylindrical aortic root replacement, performed in a similar way than the classical Bentall procedure. This technique is the most easiest one and performed more frequently than the subcoronary implantation, which is substantially more demanding. Results from centres that have significant experience with homograft valve surgery report equivalent survival data. The University of Alabama had an 87% survival at 5years in a 10-year period from 1981 to 1991. Of those who underwent isolated aortic valve replacement with a homograft, there was 99% survival at 30days and 94% survival at 8years. In the Mayo Clinic series, 82% were alive at 8years. Like all tissue valves, homograft aortic valves may fail. An understanding of the mechanisms of homograft valve failure and the way in which these mechanisms interact has important surgical implications. Homograft aortic valves may develop progressive regurgitation as a result of a change in the mechanical properties of the leaflets over time.