Bewertung eines neuartigen selbstexpandierenden Verschlusssystems für Ventrikelseptumdefekte am Tiermodell Schwein

Objective: The aim of this thesis was to first develop a method to reproducibly create an artificial midmuscular ventricular septal defect. Second, a new hybrid method closing this defect with a patch was tested. Method: The study consisted of twenty acute experiments on German landrace piglets. The artificial ventricular midmuscular septal defect was created using a sinistral thoracotomy with an enhanced 7.5 mm sharp punching instrument under two-dimensional echocardiographic guidance. The defect was closed with a new hybrid technique. The patch system was inserted over the venous neck vessels trough the artificial septal defect and was unfolded in the left ventricle. The patch was fixed to the left side of the septum using a custom-designed stapler that was introduced over the sinistral thoracotomy across the left ventricle. Results: The artificial defect was successfully created in all of the twenty attempts. Using the new hybrid method the defect was successfully closed in thirteen out of nineteen attempts. Six animals died during the intervention of various complications: Three of cardiac arrhythmias, one of loss of blood and two of technical problems. The echocardiographic and macroscopic examination did not show a dysfunction of the left ventricle or of the valve nor any persisting cardiac arrhythmias. In all successful experiments, the patch was attached evenly to the left ventricular septum. Conclusion: The improved punching instrument provides a reliable and reproducible method to create the required artificial defect at the desired midmuscular position. This allows for standardized experiments and reliable comparisons. The newly developed hybrid method allows centering the patch directly on the midmuscular ventricular septal defect. The benefit of implanting a plane patch directly to the left ventricular septum is the absence of tension on the septum or on the device framework itself during contraction of the heart.