Objective: To date, there is no suitable valved conduit for small children that demonstrates growth. Pulmonary conduits treated by the L-Hydro® process were implanted in newborn lambs to demonstrate growth potential.
Methods: The L-Hydro® process was used to treat porcine valved pulmonary conduits that were orthotopically implanted in 9 newborn lambs using extracorporeal circulation. Of the 8 survivors 7 were kept alive for 12 months after implantation. Diameter of the conduits and gradient across the valves at surgery, 3 and 9 months post-op were evaluated using bi-directional echocardiographic and angiographic methods before sacrifice. After necropsy, histological and radiological analysis were performed.
Results: The average weight of the animals was 4.2 kg at implantation, and 43.1 kg at sacrifice (p<0.05). There was significant increase in the average valve area, 139.9 mm2 at implantation and 443.4 mm2 at sacrifice (p<0.05). Pre-sacrifice angiographic examination showed absence of transvalvular gradient. The radiographic analysis did not reveal significant conduit wall or leaflet calcification in any of the animals. Histological analysis of the grafts demonstrated total integration with native-like intact valve leaflets.
Conclusion: Functional evaluation, echocardiographic analysis and histology demonstrated evidence of growth of the grafts without calcification and completely endothelialized and normal native-like pulmonary valve leaflets.