New device for closure of muscular ventricular septal defects in a canine model

Background-Repair of muscular ventricular septal defects (MVSDs) has always been challenging to the surgeon. Long-term morbidity and mortality are sig nificantly increased if the defects are closed via left ventriculotomy or i f they are associated with other complex congenital anomalies. The purpose of this study was to close MVSDs with the Amplatz ventricular septal defect device. This device is constructed from 0.004-in nitinol wire mesh filled with polyester fibers. It is retrievable, repositionable, self-centering, a nd of low profile. Methods and Results-MVSDs were created with the help of a sharp punch in 10 dogs. The location of the defects was anterior muscular (n=3), midmuscular (n=3), apical (n=3), and inlet muscular (n=1). The diameter of the defects ranged from 6 to 14 mm. All defects were closed in the catheterization lab oratory. The device was placed with the help of transesophageal echocardiog raphy and fluoroscopy, A 7F sheath was used to deploy the device from the r ight ventricular side in 8 and the left ventricular side in 2 dogs. Placeme nt was successful in all animals. The complete closure rate was 30% (3/10) immediately after placement and 100% at 1-week follow-up, Pathological exam ination of the heart revealed complete endothelialization of the device in dogs killed after 3 months. Conclusions-The Amplatz ventricular septal defect device appears highly eff icacious in closing MVSDs, The advantages include a small delivery sheath, complete retrievability before release, and the fact that it is self-center ing and self-expanding, thereby making it an attractive option in smaller c hildren.