A collapsible medical device for occluding an aperture in a body, e.g., a patent foramen ovale (PFO), is disclosed. The device includes a distal end and a distal portion for contacting the distal side of tissue, a proximal end and a proximal portion for contacting the proximal side tissue, a center joint for extending through the aperture and being hollow in the center. The center joint engages the distal and proximal portions and has a variable length to accommodate tissues of different thickness. The device also includes a catch system for holding the collapsible medical device in an expanded configuration. The catch system includes a distal threaded catch portion engaging the distal end and a proximal threaded catch portion engaging the proximate end. The threaded portions rotate relative to one another and cooperate through the center joint to vary a distance between the distal and proximal ends.
