Cobra-head and other shape-memory abnormalities of nitinol atrial septal occluders: incidence, predisposing factors, and outcomes.

Deformations were frequent in 11.8% of atrial septal occluders on a targeted search. Oversized and angulated/kinked sheaths, special techniques like pulmonary vein deployment and twist in device waist during procedure predisposed to deformities. While most deformities were corrected with manipulations, removal of the device was infrequently needed and change of device was rarely required. Long procedural time and multiple attempts for deployment did not affect procedural success.