Porcine small intestine submucosa as a pulmonary valve leaflet substitute

Background and aim of study: Isolated porcine small intestine submucosa has been used as a resorbable bio-scaffold for site-specific tissue remodeling . This study performed in swine evaluated the functional competency and rem odeling characteristics of cardiac pulmonary leaflets constructed from porc ine-derived small intestine submucosa. Methods: Four clinically normal swine were used for this study. Under gener al anesthesia and cardiopulmonary bypass, each swine had one pulmonary valv e leaflet excised and replaced with a leaflet constructed from a single lay er of porcine small intestine submucosa. The animals were sacrificed one ea ch, at 56, 63, 88 and 111 days postoperatively. Histopathological evaluatio n was carried out to compare substitute leaflets with normal host valve lea flets, and valve functional competence was determined using echocardiograph y. Results: Histopathological analysis of the substituted valve leaflet at the time of sacrifice revealed that, simultaneous with resorption of the submu cosal matrix, progressive replacement with fibrous connective tissue and mi crovasculature similar to mature host tissue had occurred. Factor VIII stai ning demonstrated progression of endothelialization of all substitute leafl et surfaces with time. Normal valvular competence was noted immediately fol lowing surgery, and at the time of sacrifice. Conclusion: This study supports the hypothesis that single-layer porcine sm all intestine submucosa can be used to replace mature pulmonary valve leafl ets. The implanted matrix is resorbed, and a leaflet with histologically id entifiable features, normal functional competency and anatomic apposition t o the host leaflets remains.