A device prepares leaflets for cardiovascular valve reconstruction from a pericardial tissue sheet harvested from a patient. A cutting tool is adapted to cut a predetermined pattern having a selected leaflet size. The device is continuously adjustable using a plurality of slidable blade segments forming a closed periphery. Radially-slidable links are slidably attached to respective blade segments. An adjustment disc is coupled to the links, wherein rotation of the adjustment disc varies a radial position of the links to modify an overlapping of the blade segments in order to select a corresponding size of the closed periphery.