Background and aim of the study: Synthetic materials used for pulmonary autograft (PA) reinforcement in the Ross procedure fail to match the demand for structural growth, have only a limited longevity, and do not guarantee adequate vascular compliance in high-pressure load systems. The study aim was to develop a resorbable reinforcement of a PA, tailored to provide structural support and to guide the process of wall structure modification for the preservation of graft viability.
Methods: An experimental model of translocation of the pulmonary trunk as an autograft in the aortic position was developed and performed under cardiopulmonary bypass in young lambs. The PA was left without reinforcement, reinforced with standard commercially available mesh, or reinforced with resorbable mesh of polyglactin and polydioxanone.
Results: Based on vessel diameter measurements by transesophageal echography at day 0 and at six months postoperatively, only the PA with resorbable reinforcement showed a behavior similar to that of the normal aorta in a growing lamb. With the non-resorbable reinforcement, transmural migration of the mesh was observed, accompanied by a conspicuous inflammatory infiltrate and fibrosis.
Conclusion: The resorbable mesh allowed for histological wall modification, characterized by the presence of highly organized smooth muscle cells and elastic lamellae in the media. The mechanical and histological features of this resorbable mesh-reinforced PA may be crucial to the clinical long-term success of the Ross procedure.