An elongate resilient tube of a mesh of shape memory alloy is used to therapeutically occlude an opening in body tissue. The tube is compressible so that it can be delivered to the opening in the body within a catheter. The tube self-expands as it is released from the catheter to contiguously form, sequentially, the following shapes: an outer bell-shaped structure; an inner bell-shaped structure disposed within the outer bell-shaped structure to conformingly engage an inner side of the outer bell-shaped structure; a tubular connector having a diameter substantially smaller than the inner bell-shaped structure, the tubular connector extending away from an apex of the inner bell-shaped structure; an inner plate-shaped structure; an outer plate-shaped structure; and a releasable connector. The bell shape is placed on one side of the opening, and the plate shape is placed on the other side of the opening, the connector passing through the opening.