Two-step heart valve implantation

A method of treating a defective native aortic valve in a human heart, comprising:

• creating an incision in a chest wall of a patient and accessing the native aortic valve through an apex of the heart;
• advancing a balloon through the incision in the chest wall and inflating the balloon within the native aortic valve;
• advancing a first percutaneously implantable heart valve in a crimped state through the incision in the chest wall and apex of the heart, the first percutaneously implantable heart valve comprising a radially-expandable first stent supporting a radially-expandable temporary valve within an interior portion of the first stent;
• positioning the first stent within the native aortic valve;
• expanding the first stent to an operational diameter within the native aortic valve, compressing the native leaflets, so that the temporary valve becomes operational;
• while the incision in the chest wall remains open, advancing a second percutaneously implantable heart valve in a crimped state through the incision in the chest wall and apex of the heart, the second percutaneously implantable heart valve comprising a radially-expandable second stent supporting a radially-expandable replacement valve within an interior portion of the second stent;
• positioning the radially-expandable second stent within the operational temporary valve of the expanded first stent;
• and
• expanding the radially-expandable second stent so as to compress the temporary valve between the first stent and the second stent while maintaining the first stent at the operational diameter;
• wherein, after expansion of the second stent, the replacement valve becomes operational for replacing the function of the defective native aortic valve.