Plugs and methods for plugging septal defects and blood vessels are provided. Plugs are delivered via catheter to a septal defect or a location where it is desired to occlude blood flow in a blood vessel. The plugs are positioned and expanded at the treatment site. The expansion of the plugs can be accomplished passively by using a heat-treated elastic frame or actively by using a balloon to deform a plastically-de frame. Plugging structures mounted to the frame span the defect or lumen and prevent blood flow. The plugs described herein have small profiles, and are more reliable than preceding intraluminal transcatheter methods.
