Device closure of patent foramen ovale with the Cardia Intrasept device
Following the introduction of the Cardia PFOOccluder (Cardia, Inc Burnsville, MN) in 1998, it has been systematically modified without changing the general concept of the device, which consists of a double umbrella design with Ivalon sails mounted on Nitinol wires. The sails (0.5 mm thick) are attached to the struts with polypropylene sutures. The free end of each of the stiff Nitinol ‘arms’ is blunted with a smooth metal tip, in order to prevent their digging into the tissues. The last generation (IV) of the device is called Intrasept (Figure 28.1). The peculiarity is the dual articulating sails with a titanium center post and struts with 19 individual strands of Nitinol that are supposed to maximize fatigue resistance, reducing the risk of wire fracture. The device is available in 20, 25, 30, and 35 mm sizes.The size represents the maximum diameter of the umbrella when measured from tip to tip of an arm. The Cardia device comes as a Cardia PFO kit, which
includes a delivery cable and a 5 French bioptome. Each jaw of the bioptome has a tiny notch which creates a small hole when they are closed. In addition to the hole in the jaws, there is a very secure locking screw mechanism at the proximal end of the delivery cable. The legs of the Cardia devices are flexible from the center, but the individual legs do not bend or flex at any point.This characteristic makes them less conforming to a constraining tunnel; the titanium pivoting center post of the IV generation is supposed to help in this case.