An apparatus for manipulating a medical device is formed of at least three coupled
movable blades which are disposed about a reference circle to form an aperture
whose size may be varied. The aperture capable of being sized to contain a medical
device. Each blade is in communication with an actuation device which is capable
of moving the blade to alter the size of the aperture. Each blade includes a single
radial point which a) lies on the circumference of the reference circle prior to
movement of the blade, and b) may be moved only along a radius of the reference
circle on movement of the blade.
