The pathology of fresh and cryopreserved homograft heart valves: An analysis of forty explanted homograft valves

Photomicrograph of radial sections of an unimplanted cryopreserved aortic valve and midterm explant. (Routine H&E staining; original magnification 250×.) A, Unimplanted cryopreserved aortic homograft valve. Note the carefully arranged collagen bundles and rippled outflow surface as an expression of leaflet elasticity. B, Cryopreserved aortic homograft from a beating-heart donor implanted in a 20-year-old woman in the RVOT and explanted after 2.5 years because of stenosis caused by thickening of the vessel wall. The leaflet shows the typical loss of tissue architecture and cellular elements, stretching of collagen (loss of elasticity), and increase in ground-substance volume.

Mean cellularity for both arterial wall and leaflet tissue samples of unimplanted and explanted homografts. Explanted homografts are grouped according to their implantation time.

Mean cellularity for leaflet tissue samples. Explanted grafts are grouped according to implantation time and reason for explantation. Within the implantation time groups of 3 to 5 years and greater than 10 years, no homografts were explanted for technical reasons. One valve in the implantation group of greater than 10 years was explanted because of endocarditis.

Mean trilaminar structure for leaflet tissue samples. Explanted grafts are grouped according to implantation time and reason for explantation. Within the implantation groups of 3 to 5 years and greater than 10 years, no homografts were explanted for technical reasons. One valve in the implantation group of greater than 10 years was explanted because of endocarditis.

Photomicrograph of radial sections of a cryopreserved aortic valve homograft harvested from a beating-heart donor (age, 48 years). The graft was used as aortic valve replacement in a 30-year-old woman and explanted after 2 weeks because of paravalvular leakage (without any sings of endocarditis). A, H&E staining of the hinge area of the valve, with the sinus wall (W) on the right and the proximal part of the cusp on the left. (Original magnification 250×.) B, Immunohistochemistry of the same area with monoclonal antibodies directed against monocytes and macrophages (anti-CD68). The infiltration of inflammatory cells in the hinge area is clearly demonstrated. (Dark-brown coloring of immunoperoxidase; original magnification 250×.) C, Detail of the aortic site of the hinge area in which infiltration of T lymphocytes in the intimal layer is demonstrated with anti-CD3 monoclonal antibodies.

Mean influx of inflammatory cells (macrophages and T lymphocytes) in wall tissue samples. Explanted grafts are grouped according to implantation time.