Left atrial appendage closure with the Amplatzer™ Cardiac Plug: Rationale for a higher degree of device oversizing at implantation.

BACKGROUND In left atrial appendage (LAA) closure, the correct sizing of the implantable devices is crucial. Data on the time-dependent changes in the shape and positioning of LAA occlusion devices are missing. We analyzed the results of 33 consecutive patients after implantation of an Amplatzer™ Cardiac Plug (ACP) LAA closure device to get more information on the optimal device sizing during implantation. METHODS AND RESULTS Thirty-three consecutive patients were enrolled in this observational study. ACP implantation was guided by fluoroscopy and three dimensional transesophageal echocardiography (3-D TEE). Device sizing was based on the largest measured diameter of the intended landing zone adding 2-4 mm of device oversizing. Fluoroscopies were performed at 1 day after, and after 3 months, control 3-D TEE was performed 3 months after implantation. The stability of device positioning and shape was matched with the results of 3-D TEE. Patients' mean age was 70.2 ± 8 years; mean CHA2DS2VASc score was 3.8 ± 1.1. According to the manufacture's classification, the post-implant degree of compression of the device-lobe was classified in three categories 1) undercompression "square-like shape" (1 patient); 2) optimal compression "tire-like shape" (20 patients), 3) overcompression "strawberry-like shape" (12 patients). Changes in the degree of device compression by more than one classification class occurred in 18/33 of our patients. A complete loss of device compression ("square-like shape") was observed in 9 patients. Despite the changes in device compression, a complete closure of the LAA was achieved in 32/33 patients. CONCLUSIONS There is a temporal change in shape and positioning of the ACP within 3 months after implantation. A late decompression of the ACP lobe was observed in 61% of our patients, leading to a complete loss in device compression in 27%. This observation may be the rationale for a higher degree of ACP oversizing during implantation.