Abstract 19831: Pre-clinical in vivo Evaluation of Cormatrix as Right-sided Valved Conduit

Introduction: Although not FDA approved for heart valve repair, decellularized porcine small intestinal submucosa (Cormatrix) is currently used in quite a lot of institutes to reconstruct heart valves in patients. Recently, surgeons experienced clinical failures using Cormatrix as a patch in heart valve repair and words of caution were raised. The aim of this study was to pre-clinically evaluate CorMatrix as right-sided heart valved conduit in a xenogeneic animal model. Methods: CorMatrix was used as valved conduit in the right ventricular outflow tract in sheep (n=10) and lambs (n=10). Valved conduits were home-made and explanted after 1 month, 3 months or 6 months. Valve function was assessed by echocardiography directly after implantation and prior to termination. Explants were analyzed using histology, scanning electron microscopy, mechanical testing, biochemical analysis and immunohistochemistry. Results: All valved conduits were successfully implanted. 5 sheep and 2 lambs did not survive until planned follow-up. Diseased animals died due to valve failure after 1 or 2 months. Valve leaflets where thickened with signs of a massive inflammatory response. 5 sheep (1 month n=3, 3 months n=1 and 6 months n=1) and 8 lambs (1 month n=3, 3 months n=3, 6 months n=2) survived until planned follow up. In these animals, on echocardiography a well functioning valve with no signs of stenosis or insufficiency was seen. However all explants showed only limited signs of cellular infiltration or neotissue formation. Conclusions: In the chronic sheep and lamb model, 13 out of 20 CorMatrix pulmonary valved conduits were intact and showed good functionality, although only limited signs of tissue remodeling. However, 7 out of 20 valves failed owing to a massive inflammatory response. Further analysis is needed to understand the disturbing dichotomous outcome before clinical application can be advised