Viable vascularized autologous patch for transmural myocardial reconstruction.

OBJECTIVE: Various patch materials currently used for cardiac reconstruction represent non-viable tissue with high susceptibility to infection and degeneration. We therefore introduce an innovative, autologous vascularized matrix with high regenerative potential for myocardial reconstruction.
METHODS: Autologous small bowel segments without mucosa, but with both the adjacent jejunal artery and vein, were harvested and used in a single-stage procedure for the replacement of right ventricular transmural defects (2 cm x 3 cm) in pigs (group A; n = 3). The autografts were revascularized by connecting jejunal vessels to the right internal thoracic artery and vein. Autologous pericardium was used as controls (group B; n = 3). All procedures were performed on beating hearts using a right heart bypass. After explantation (up to 6 months), the patches were investigated by standard histological analyses, immunohistochemistry and confocal microscopy.
RESULTS: Postoperative complications, for example excessive bleeding, graft rupture or dislodgement due to the dynamic cardiac contractions, did not occur. In group A, newly formed cardiomyocytes positively stained for Nkx 2.5 and myosin heavy chain were identified 1 month after operation. The cardiomyocytes were localized in close proximity to mesenteric capillaries in a disseminated-like pattern and showed a strong tendency to form islets. In contrast, explanted pericardial patches appeared as fibrotic tissue without evidence of myocardial cells inside the patch.
CONCLUSION: We developed a novel autologous graft with preserved vascularity that can be used for myocardial grafting. This vascularized matrix undergoes autologous repopulation with cardiomyocytes after transmural myocardial replacement. Vascularization represents an important prerequisite for myocardial guided tissue regeneration.