History

History of the Mechanical Valve

            Artificial heart valves have been used for decades in the medical field to replace and fix damaged and poorly functioning heart valves. Currently, there are two main classes of artificial heart valves: mechanical heart valves and bio-prosthetic heart valves. The first mechanical heart valve replacement was performed by Hufnagel in 1952 with the caged-ball design. This design can allow for a small gap to form between the ball and cage causing mild regurgitation. The success and feasibility of heart valve replacement was aided by the necessary use of the heart lung bypass machine during surgery. The early designs of the mechanical heart valves had many setbacks even though they can still be chosen to be used by surgeons today. In the late 1960s, the more efficient tilting-disk design was introduced. Most recent designs are based on the bileaflet mechanical valve design. This design has three regions for blood flow. As blood travels down the valve, bloodflow is more evenly distributed. Minimal backflow can occur, but it is much less than in previous models. In 1966, pyrolytic carbon was introduced with the bileaflet design. This material is now the material of choice for mechanical heart valves because it is biocompatible, thromboresistant and wear resistant. Many improvements are continually attempted on the bileaflet pyrolytic valve design. The mechanical valve though successful, however, requires life-long dependence on anticoagulants or anticoagulation therapy and can cause bleeding. In contrast, the bioprosthetic heart valve can have less risks if successful. The use of the tissue heart valves began with the first Ross Procedure in 1967 where the patient’s own pulmonary valve was used to replace their failing aortic valve. The latest developments in using tissue heart valves have been the successful implantation of porcine and pericardial valves into human hearts.

Timeline of important events in the development of artificial heart valves

Source of History of Artificial Heart Valves