Evaluation of a new hybrid technique for closure of muscular ventricular septal defects in a long-term setting

ObjectiveTherapy for muscular ventricular septal defects beyond the moderator band, especially in neonates and infants, has always been challenging for both surgeons and cardiologists. Recently, we established a patch closure hybrid therapy for muscular ventricular septal defects. In this study, we evaluated it in a long-term porcine model.MethodsThirteen minipigs underwent anterolateral thoracotomy to expose the left ventricle. Muscular ventricular septal defects were created under 2- and 3-dimensional echocardiographic guidance with a 7.5-mm sharp punch instrument. Closure of the defects was undertaken with our new patch system in hybrid technique. Animals were observed for 3 months. Echocardiographic evaluation and pathologic examination, including immunohistochemical staining, were undertaken.ResultsDefects were successfully created in 12 pigs and closed in 10 pigs. Seven survived for 3 months. Residual shunting was noticed in 1 animal. Neither left ventricular dysfunction nor relevant damage to the valves could be detected. Pathologic examination showed complete endothelialization of the patch and the nitinol anchors without protruding parts of the system. Cellular organization was proceeding. Immunohistochemical staining demonstrated endothelial cells on the surface of the patch and fibromuscular cells around the patch.ConclusionOur hybrid therapy was efficacious in closing muscular ventricular septal defects without impairment of cardiac function. The patch system and nitinol anchors demonstrated good integration into the septum. Further development of the system for human application is already being undertaken.