The first atrial septal defects (ASDs) were closed percutaneously in 1974 and reports about their closure published in 1976.¹ In the 1980s the Rashkind occluder was introduced and revived the interest in the topic,² focusing for the first time on the patent foramen ovale (PFO).³ This device is still available in two modified versions. Its initial name, Rashkind Clamshell occluder, has been changed, first into CardioSEAL and more recently into STARFlex (Nitinol Medical Technologies, Boston, Massachusetts, USA). Two other devices are the Sideris Buttoned Device (Custom Medical Devices, Amarillo, Texas, USA) and the Angel Wings device (Microvena Corp, Whitebear Lake, Minnesota, USA), more recently called the Guardian Angel device. The ASDOS device and the Monodisk device are no longer on the market. All these devices had one major problem in common pertaining to the closure of ASDs. They were not self-centering. Although some efforts were made to remedy this with intricate nitinol wire constructions or interlinking filaments, the only self-centering device was introduced in the 1990s—the Amplatzer ASD occluder.⁴ Figure 1 shows a selection of these devices.

The PFO was initially considered by interventional cardiologists simply as one of the manifestations of an ASD to be left to their paediatric colleagues. However, about 10 years ago, it was realised that the PFO not only represented the most common form of an ASD but that it also exhibited its problems exclusively in adults and represented the easiest target for closure. A derivative of the Clamshell occluder was dedicated to PFO closure and named PFO STAR (Cardia, Burnsville, Minnesota, USA); the Amplatzer occluder was modified for the PFO indication and first implanted on 10 September 1997 by the author in the presence of Kurt Amplatz, the …