![]() Mechanical heart valves can also cause mechanical hemolytic anemia, a condition where the red blood cells are damaged as they pass through the valve. People with mechanical valves need to take anticoagulants (blood thinners), such as warfarin, for the rest of their life. Clots formed by red blood cell and platelet damage can block blood vessels leading to stroke. One of the major drawbacks of mechanical heart valves is that they are associated with an increased risk of blood clots. Made from metal and/or pyrolytic carbon, they can last 20–30 years. The major advantage of mechanical valves over bioprosthetic valves is their greater durability. They are, however, vulnerable to blood backflow. With a larger opening than caged ball or tilting-disc valves, they carry a lower risk of blood clots. Introduced in 1979, bileaflet valves are made of two semicircular leaflets that revolve around struts attached to the valve housing. Ĭaged ball valves are strongly associated with blood clot formation, so people who have one required a high degree of anticoagulation, usually with a target INR of 3.0–4.5. The Starr-Edwards valve was first implanted in a human on August 25, 1960, and was discontinued by Edwards Lifesciences in 2007. This consisted of a silicone ball enclosed in a methyl metacrylate cage welded to a ring. A similar valve was invented by Miles 'Lowell' Edwards and Albert Starr in 1960, commonly referred to as the Starr-Edwards silastic ball valve. Hufnagel implanted caged ball heart valves into ten patients (six of whom survived the operation), marking the first success in prosthetic heart valves. When the heart finishes contracting, the pressure inside the chamber drops and the ball moves back against the base of the valve forming a seal. When the heart contracts and the blood pressure in the chamber of the heart exceeds the pressure on the outside of the chamber, the ball is pushed against the cage and allows blood to flow. The first artificial heart valve was the caged ball valve, a type of ball check valve, in which a ball is housed inside a cage. Bileaflet valves are the most common type of mechanical valve implanted in patients today. Caged ball valves are no longer implanted. Mechanical valves come in three main types – caged ball, tilting-disc and bileaflet – with various modifications on these designs. Companies that manufacture heart valves include Edwards Lifesciences, Medtronic, Abbott (St. Jude Medical), CryoLife, and LifeNet Health. Mechanical valves are more commonly used in Asia and Latin America. In the US, UK and the European Union, the most common type of artificial heart valve is the bioprosthetic valve. The three main types of artificial heart valves are mechanical, biological (bioprosthetic/tissue), and tissue-engineered valves. High blood pressure and heart failure which can enlarge the heart and arteries, and scar tissue can form after a heart attack or injury. There are many potential causes of heart valve damage, such as birth defects, age related changes, and effects from other disorders, such as rheumatic fever and infections causing endocarditis. ![]() The left ventricle pumps blood to the aorta through the aortic valve. After being oxygenated, blood passes to the left atrium, where is it pumped through the mitral valve to the left ventricle. From there, blood is pumped through the pulmonary valve to enter the lungs. Blood enters the heart in the right atrium and passes through the tricuspid valve to the right ventricle. Background ģD Medical Animation still shot of Artificial Heart ValveĪ heart contains four valves (tricuspid, pulmonary, mitral and aortic valves) which open and close as blood passes through the heart. While some dysfunctional valves can be treated with drugs or repaired, others need to be replaced with an artificial valve. Both processes put strain on the heart and may lead to serious problems, including heart failure. Heart valves can malfunction for a variety of reasons, which can impede the flow of blood through the valve ( stenosis) and/or let blood flow backwards through the valve ( regurgitation). Their main purpose is to keep blood flowing in the proper direction through the heart, and from the heart into the major blood vessels connected to it (the pulmonary artery and the aorta). The human heart contains four valves: tricuspid valve, pulmonary valve, mitral valve and aortic valve. ![]() Artificial heart valves can be separated into three broad classes: mechanical heart valves, bioprosthetic tissue valves and engineered tissue valves. An artificial heart valve is a one-way valve implanted into a person's heart to replace a heart valve that is not functioning properly ( valvular heart disease). ![]()
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