Techniques for trans-catheter retrieval of embolized Nit-Occlud PDA-R and ASD-R devices

BACKGROUND: Nit-Occlud (atrial septal defect) ASD-R and (patent ductus arteriosus) PDA-R devices are used outside the United States for percutaneous closure of the patent ductus arteriosus and atrial septal defects. When embolization occurs, these devices have been difficult to retrieve. METHODS: Bench simulations of retrieval of PDA-R and ASD-R devices were performed in a vascular model. Retrieval of each device was attempted using snare techniques or with bioptome forceps with a range of devices. The same devices were then intentionally embolized in an animal model. Retrieval methods were systematically tested in a range of sheath sizes, and graded in terms of difficulty and retrieval time. Results: Devices that were grasped by the bioptome in the center of the proximal part of the devices were easily retrieved in both models. Bench studies determined the minimum sheath sizes needed for retrieval of each device with this method. In general sheathes two french sizes greater than the delivery sheath were successful with this technique. Three out of the four PDA-R devices were successfully retrieved in vivo. Two were retrieved by grasping the middle of the PA end of the PDA-R device with a Maslanka bioptome and one small PDA-R device was retrieved using a 10 mm Snare. Four of the five ASD-R devices were retrieved successfully grasping the right atrial ASD-R disc or by passing a wire through the device and snaring this loop. For ASD-R 28 and 30 mm devices, a double bioptome technique was needed to retrieve the device. CONCLUSION: ASD-R and PDA-R devices can be successfully retrieved in the catheterization lab. It is critical to grab the center portion of the right atrial disc of the ASD-R device or pulmonary portion of the PDA-R device and to use adequately sized sheathes.

Transcatheter closure of large patent ductus arteriosus at high altitude with a novel nitinol device.

BACKGROUND: Patent ducti arteriosi (PDAs) are more frequent and larger at high altitude than at sea level. A novel PDA closure device, the Nitocclud PDA-R, is designed specifically for both large and medium size PDAs. The initial clinical experience with a new nitinol-based device in high altitude patients with large PDAs is described. METHODS: The Nitocclud PDA-R is a self-expandable, self-centering, repositionable occluder made of one nitinol wire without use of welding. It contains several polyester membranes, is delivered with a central guide wire and is released by retraction of the central wire into the delivery catheter. The efficacy of this device was evaluated at several high altitude centers. RESULTS: Fifty-one patients without other congenital cardiac defects underwent transcatheter closure of PDA. Complete occlusion of the PDA was achieved in 98% of the patients. Nearly 49% of the patients had no shunt immediately after device implantation. Echocardiography revealed a complete closure rate by Doppler interrogation of 69% after 24 hr, 96% after 6 months, and 98% after 1 year. In two cases, device embolization was observed after release, and in both cases the device was easily retrieved with standard interventional techniques. There have been no episodes of delayed device migration, endocarditis, hemolysis, wire fracture, device disruption, or death. CONCLUSIONS: The Nitocclud PDA-R device is safe and effective and can easily close very large PDAs. This device has a high rate of complete occlusion within 1 year and is easily retrieved if embolized.