Abstract: A surgical instrument is used for temporary use in a medical procedure in a mammalian body. The surgical instrument is configured to be changed between two shapes upon application of one or both of heating and cooling. The instrument includes a first member, a second member having a surface configured to contact tissue, and a means to apply heating or cooling to one or both of the first member and the second member to change the shape between a first shape and a second shape. A surgical instrument also may be configured to be changed between two shapes upon removal of a constraining force. The surgical instrument includes a first member, a second member having a surface configured to contact tissue, and a constraining means to apply a constraining force to one or both of the first member and the second member to cause one or both of the first member and the second member to be in a first constrained shape. The surgical instruments may be used in minimally invasive valve surgery.

Abstract: A tissue cutting device includes a catheter with a window at its distal tip for admitting tissue into a catheter compartment. A cylindrical cartridge in the compartment has a cutting edge that supports an electrically conductive cutting element, e.g. a band or wire. The cutting element and adjacent tissue can be heated to a selected temperature by generating an electrical current through the cutting element. The catheter is maneuverable to position its distal end near the tissue to be cut. The catheter incorporates a vacuum feature that urges tissue into the compartment prior to cutting or severing and assists in holding the tissue during the cutting or severing process. Then, the cartridge is manipulated from the catheter's proximal end to move the cutting edge across the window, cutting the tissue. According to alternative embodiments, the cartridge is either rotated or moved axially relative to the catheter and, in either event may be capable of closing the catheter window when the cut is complete.