Aortic and mitral valve replacement is a surgical procedure on the heart. It is done when the valves have become narrowed (aortic stenosis) or leaky (aortic regurgitation). The replacement valves may be mechanical (metal, plastic) or biological prostheses. The Swiss Atlas of Healthcare contains analyses on the frequency of inpatient aortic and mitral valve replacement procedures in total and separate analyses on aortic valves and mitral valves.