Interventional device closure of perimembranous ventricular septal defects: challenges, pitfalls, and advancements in device technology

Percutaneous closure is the standard therapy for muscular Ventricular Septal Defects (VSDs) beyond infancy with a low rate of major complications. The story is somewhat different for Perimembranous Ventricular Septal Defects (PmVSDs) where surgery remains in 2021 the preferable treatment approach in some centers, due to the historical incidence of Complete Atrioventricular Block (CAVB) that has been associated with the asymmetrical Amplatzer Membranous VSD Occluder. It is certain that transcatheter closure of PmVSD is one of the most complex cardiac interventions and have stringent demands on device design due to several challenging considerations. Despite that, experienced interventionists have been continuously reporting successful experiences with PmVSD closure using a variety of off-label device occluders. Recent meta-analyses confirmed the very good outcomes of this approach and the noninferiority compared to surgery. However, these devices represent a compromise, as they are not specifically designed to be placed in the perimembranous position. To date, no device achieved market approval in the United States. The need for a device dedicated to PmVSD transcatheter closure is mandatory to standardize the technique and we are very close to achieving this goal. The most recent KONAR-Multifunctional Occluder (MFO) has been smartly designed, combining technical features of previous devices, to tackle encountered difficulties and the outcomes of emerging clinical reports are consecutively encouraging. The MFO specifications are particular but limitations are present and need to be highlighted. This continuous advancement in device technology through continuous physician input will lead to the birth of the ideal device for this intervention