Aortic valve replacement is a procedure whereby the failing aortic valve of a patient's heart is replaced with an artificial heart valve. The aortic valve may need to be replaced because: The valve is leaky (aortic insufficiency, also known as aortic regurgitation) The valve is narrowed and doesn't open fully (aortic stenosis) Current methods for aortic valve replacement include open-heart surgery, termed minimally invasive cardiac surgery (MICS) or surgical aortic valve replacement (SAVR) and percutaneous or transcatheter aortic valve replacement (TAVR; also PAVR, PAVI, TAVI). A competent practising cardiologist can evaluate whether a patient could benefit from heart valve repair. History During the late 1940s and early 1950s, the first surgical approaches towards treating aortic valve stenosis had limited success. The first attempts were valvotomies, (i.e. cutting the valve while the heart is pumping). A ball valve prosthesis placed on the descending thoracic aorta (heterotopically) was developed by Hufnagel, Harvey and others to address aortic stenosis, but had disastrous complications. Later, with the innovation of cardiopulmonary bypass, the ball valve prosthesis was placed orthotopically (i.e. in same place as the original aortic valve). This first generation of prosthetic valves was durable, but needed intense anti-coagulation, and cardiac hemodynamics were compromised. During the mid-1950s, a single-leaflet prosthesis was developed by Bahnson et al. In early 1960, Ross and Barratt-Boyes used allografts. Tissue prosthetic valves were introduced in 1965 by Binet in Paris, but they degenerated quickly because the tissue was insufficiently preserved. Carpentier solved this problem by introducing glutaraldehyde-preserved stent-mounted porcine valves. Anatomy, physiology and pathophysiology The aortic valve is semilunar (half-moon shaped) with three cusps. It separates the heart from the aorta. Each cusp is attached to the aortic wall creating a sinus; a Valsalva sinus. The origins of the two coronary arteries are sited in two Valsalva sinuses, each named after the coronary artery they supply. Leaflets are separated by commissures. The posterior leaflet is in continuation with the anterior leaflet of the mitral valve (the tissue is called the aorto-mitral curtain). The aortic valve is opened during systole, the driving force for it to open is the difference in pressure between the contracting left ventricle of the heart and the aorta. During cardiac diastole (when the heart chamber gets bigger) the aortic valve closes. Aortic stenosis most commonly is the result of calcification of the cusps. Other reasons for stenosis are the bicuspid valve (some patients have only