A resizable valve base for a cardiovascular valve assembly that is comprised of the resizable valve base and a valve member that is detachably coupled thereto. The resizable valve base has adjustable dimensions to allow use with both small and large size valve members. The valve base comprises a frame comprised of a plurality of frame sections, and each frame section includes a mounting portion and a pair of arcuate portions extending from opposite sides of the mounting portion. The valve base also includes a plurality of joining elements for joining together the frame sections to define a generally cylindrical opening having a diameter, wherein said plurality of joining elements allow adjacent frame sections to move towards or away from each other in order to modify the diameter of the opening, thereby moving the valve base between a collapsed position and an expanded position.