Transcatheter closure of large atrial septal defects with the Babic system.

An improved 10 Fr version of the atrial septal defect (ASD) occlusion system consisting of two umbrellas for transvenous introduction over the long veno-arterial guide-wire was used to attempt closure in five adult patients with large defects (26-35 mm). The umbrellas are made of nitinol wire frame and a thin membrane of microporous polyurethane. Supported by the metal cannula and guided by selective left atriography, the umbrellas of 45-60 mm were placed individually into the atria and screwed together at the septum level by means of a torquer catheter. Positioning and screwing on, unscrewing, separating, and repositioning the umbrellas up to 17 times were needed to anchor the prosthesis correctly in a patient. The prosthesis could be implanted primarily in all patients (in one at second session). Dislodgement of a 60 mm prosthesis and left atrial perforation with a 55 mm prosthesis required surgery in two patients 8 hours and 2 weeks post procedure, respectively. A single umbrella-arm fracture was noticed in one patient 4 months after the implantation. All five patients were free of symptoms at follow-up after 7-10 months. Transcatheter closure of large ASDs is technically feasible with this system. The morbidity is mainly associated with the implantation of very large umbrellas.