Experiences in occluderimplantation for closure of secundum atrial septal defects

This PhD thesis aims at several objectives: Firstly, it presents, evaluates and discusses hand-collected data of transcatheter closure of secundum atrial septal defects at the University Medical Center in Goettingen. Secondly, it documents defect sizes, both measured by TTE and balloon sizing and links them to recent publications. Thirdly, it evaluates different aspects documented during the observation period with regard to i) the duration of each treatment, and ii) intra- as well as post interventional complications as well as the necessary radiation dose needed for implantation for each occluder type. A total of 169 patients were treated for transcatheter closure of secundum atrial septal defect at the Department of Cardiology at the University Medical Center in Goettingen between 01/01/2000 and 31/12/2010. Out of this group 148 patients were treated successfully. Five different occluder systems by different vendors were used: the Amplatzer septal occluder (n=114), the Starflex septal occluder (n=25), the Helex septal occluder (n=13), the Biostar occluder (n=14) and the Solysafe occluder (n=3). At the end of the observation period (mean of 4.8 years), a residual shunt was detected for only nine patients (which represents 6% of the treatment group of 148 patients). However, none of these residual shunts were hemodynamically relevant. The related literature documents an increase of post interventional rest shunts for some occluder types. This thesis confirms an increase of post interventional rest shunts for the Starflex occluder compared to the Amplatzer system. Furthermore, a statistically significant difference between the different occluder systems and the duration of treatment was observed: The time needed for implantations of the Helex septal occluder was longer than implantations using other occluder systems. This is in line with the existing literature. The analysis of the corresponding ECG reveals no significant changes of the relevant parameters which could have been caused by the intervention or during the discourse of post interventional treatment. For a total of twelve patients (roughly 8% of total patient group) an interventional therapy of ASD II was not possible during heart catheter examinations due to the quality of their atrial septum. These patients were treated surgically. For a total of nine patients (6% of total patient group) the occluder needed to be surgically removed, even after successful transcatheter closure, due to dislocation of the implant. For a total of 14 implantations (9.4% of total patient group) therapy related complications were documented. All these complications are well known and described in the relevant literature. They include arrhythmia, deformations of the occluder during the implantation process, as well as occurrence of pericardial effusions. The present thesis shows that secundum atrial septal defect closure at the Medical Center of the University in Goettingen has had a relatively low rate of rest shunts. The rate is comparable to rates documented in the comparable literature, also with respect to the kind and frequency of complications.2013-08-2