New self-expanding patent foramen ovale occlusion device.

Our purpose was to evaluate a new self-expanding device for closure of the patent foramen ovale (PFO). A transeptal catheter passage through the flap of the fossa ovalis was performed with a transeptal needle inside a catheter, creating a PFO in two minipigs. In an additional five animals, a naturally occurring PFO was found. The device is made from 0.005 inch nitinol wire mesh with polyester fabric inside, similar in construction to the Amplatzer atrial septal occluder. However, the left atrial disc is smaller (18 mm) than the right atrial disc (26 mm). Both discs are connected by a very short flexible waist (3 mm) that allows free movement of both retention discs. Pulmonary and right atrial angiography were performed after placement, at 1 month, and at 3 months follow-up. Placement of the device was technically successful in six animals. One animal died from ventricular fibrillation during placement. Pulmonary angiography and echocardiography showed complete occlusion of the PFO in six animals. Two animals were sacrificed after 1 month and four animals after 3 months. In the animals sacrificed at 1 month, histopathological examination showed partial (n = 2) endothelialization, and in the 3 months follow-up group (n = 4) endothelialization was complete. The device appears to be highly effective for occlusion of PFOs. This procedure may be performed as an outpatient procedure due to the small 7 Fr delivery system sheath. Cathet. Cardiovasc. Intervent. 47:370-376, 1999.