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Glossary of Related Medical Terms
Definitions of terms frequently used in relation to heart valve disease and replacement.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Acquired Aortic Valvular Stenosis (AAVS) A condition ranging from mild leaflet thickening without outflow obstruction, termed aortic sclerosis, to significant outflow obstruction. The most common cause of acquired aortic valvular stenosis is calcification or degenerative valve disease leading to a reduction in the valve's leaflet mobility.
Allograft (Homograft) Donor and recipient of transplanted tissue are the same species (i.e., human)
Anterior Situated in the front of or in the forward position.
Annulus A ring of tough fibrous tissue that supports the leaflets of the heart valve. It is located between the valve leaflets and the heart muscle.
Anticoagulant A drug that helps prevent the clotting (coagulation) of blood. These drugs help prevent new clots from forming or keep existing clot from enlarging. They do not dissolve an existing blood clot. Anticoagulants are given to certain people at risk of forming blood clots, for example, those with artificial heart valves or atrial fibrillation.
Anticoagulation Therapy A medically prescribed anticoagulant management program for patients at risk for blood clot formation.
Aorta The main artery that carries oxygenated blood from the left ventricle to the rest of the body.
Aortic Root The portion of the Aorta just on the outflow side of the Aortic Valve. The diameter of the aortic root can be measured just above the aortic valve cusp via an echocardiograph examination.
Aortic Valve The three cusp, semilunar valve located between the left ventricle and the aorta that prevents the flow of blood back into the left ventricle.
Aspirin Acetylsalicylic acid, a drug having anti-inflammatory, analgesic and fever reducing effects; it is used for the relief of pain and fever. It is frequently used with anticoagulation therapy to reduce the tendency of platelets in the blood to clump and clot.
Autograft A transplant from one part to another part of a patient's own body.
Bicuspid Valve The mital valve, or a valve with two cusps. In cardiology "bicuspid valve" generally refers to the common congenital abnormality of an aortic valve with two cusps, or leaflets, instead of the normal three.
Biological Valve A general term that refers to a replacement heart valve constructed with tissue, usually originating from animals or humans (e.g. a porcine heart valve, made with a harvested pig valve).
Bovine Paracardium A biological tissue derived from the outermost tissue of a cow's heart. This tissue is harvested for the construction of bovine tissue heart valves.
Calcification The process where tissue is hardened by the invasion of calcium. It may be a normal process, as in the development of bone, or abnormal as in the calcification of a heart valve.
Chordae Tendineae The fine fibrous chords (tendons) that bind the free edges of the atrio ventricular valves (the mitral valve and the tricuspid valve) to the papillary muscles. They restrict how far the valve leaflets swing when they close, preventing the valve tissue from flailing backwards and leaking.
Commissure The location on the aortic wall where adjacent cusps of a heart valve meet.
Coronary Arteries The vessels that supply blood to the heart muscle. There are two coronary arteries that originate behind two of the three leaflets of the aortic valve.
Coumadin® A trademarked brand of warfarin, an anticoagulant.
Coumarins A family of oral anticoagulant drugs (warfarin, nicoumalone and phenprocoumon) that inhibit the formation of certain blood clotting factors made by the liver.
Cryopreservation The preservation of living cells, tissues or organs by subjecting them to very low temperature processes. Cells and tissues preserved by this method maintain viability even after thawing and transplantation.
Cusps Segments of tissue which make up the flexible portion of heart valves, also called leaflets. The cusps open and close to control the direction of blood flow through the heart.
Effective Oriface Area (EOA) A calculation of the "effective" flow of an artificial valve in the fully open position. It is derived from measured parameters such as pressure losses and blood flow. The EOA is adversely affected by features that reduce the flow of blood through the valve when it is fully open.
Endocarditis An inflammation of the inner lining of the heart. Bacterial endocarditis can occur when bacteria grow on the edges of a heart defect or on the surface of an abnormal valve. A common source of infection is when bacteria enter the blood stream from dental, gastrointestinal or urinary tract procedures.
Embolism The sudden blocking of an artery by a particle (embolus), such as a thrombus, debris or an air bubble circulating in the blood stream.
Geometric Oriface Area (GOA) The area of a heart valve which is available for blood flow. It is calculated from the physical dimensions of the valve's opening.
Glutaraldehyde A chemical substance used to stabilize, sterilize and store non-living tissue or biological grafts.
Gradient A differential between two areas. In reference to heart valves, it usually quantifies the drop in pressure across a heart valve, also called a pressure gradient.
Heart-Lung Machine A mechanical device, also called a pump oxygenator or cardio-pulmonary bypass, that temporarily takes over the functions of the heart and lungs during cardiac surgery.
Hemodynamics The study of physical forces (e.g. pressure and resistance) in relation to the flow of blood. The hemodynamic performance of a heart valve is generally expressed as a pressure gradient across the valve at defined physiological conditions. Higher pressure gradients indicate greater resistance to flow.
Hemolysis Red blood cell damage, which can lead to hemolytic anemia.
Heparin An injectable drug that can be used to thin blood and inhibit blood clots by increasing the body's production of antithrombin. Heparin also may be used to prevent enlargement of clots that have already formed.
Heterograft (Xenograft) A graft in which the donor and recipient of transplanted tissue are of different species (e.g., a pig valve used in a human)
Homograft (Allograft) Donor and recipient of transplanted tissue are the same species (i.e., human)
Impingement An infringement or collision. In a heart valve, an impingement could be the entrapment of surgical thread, chordal strands or host tissue between the moving parts of the heart valve, which could interfere with the valve's function.
Incompetence With heart valves, the inability to close completely, letting blood flow in the wrong direction. Also known as insufficiency or regurgitation.
Inferior Vena Cava The large vein that delivers deoxygenated blood from the veins of the legs and lower body to the right atrium.
INR (Internationalized Normalized Ratio) A standardized measure of the clotting ability of the blood. The World Health Organization developed this protocol to standardize prothrombin time (PT: clotting response time). An INR of 1.0 is normal, adjusted for the thromboplastin (activant) used and the average normal PT at the local laboratory. An INR of 2.0 indicates double the normal PT.
Insufficiency In a heart valve, the inability of a valve to close completely, allowing blood leaks back through the valve. Small amounts of insufficiency may be inconsequential, but larger amounts may require valve surgery.
Isotropic Having properties that are not aligned to any particular orientation, i.e. the same in all directions. Isotropy is a key feature of the pyrolytic carbon used for heart valves.
Left Atrium The left upper chamber of the heart that receives oxygenated blood from the lungs via the pulmonary veins.
Leaflets The cusps or moveable elements of a natural or prosthetic heart valve.
Left Ventricle The left lower chamber of the heart, which receives oxygenated blood from the left atrium and pumps it through the aorta to the body.
Mechanical Valve A heart valve prosthesis constructed of non-tissue materials to control the direction of blood flow through the heart.
Mitral Valve A large "parachute" type bi-cuspid valve located between the left atrium and the left ventricle that prevents backflow of blood into the left atrium.
Morbid Pertaining to, arising from, or affected by disease.
Morbidity The rate of disease or proportion of diseased persons in a community.
Murmur An abnormal sound in the heart produced by vibrations of the valves, the walls of the heart and the great vessels.
More from: WebMD, The Cleveland Clinic - Murmur
Orifice Generally refers to the flow path wall and leaflet support structure of a prosthetic valve. Sometimes called a "housing."
Pannus Newly formed layer of tissue, for example, growing over a prosthetic heart valve orifice.
More from: Heart Surgery Forum - Pannus
Paravalvular Leak Leakage of blood through or around the sewing cuff of a prosthetic valve.
Porcine Valve A biological (tissue) valve derived from a pig's heart valve. (a variety of heterograft or xenograft).
Pressure Gradient The difference in pressure between the two sides of a heart valve, often referred to as pressure losses or pressure drops.
Prolapse A condition in which there is a billowing or "outpouching" of the valve leaflet. In its severe form the valve will allow blood to flow backward when the valve is closed (insufficiency).
Information and Support : Mitral Valve Prolapse Syndrome Research and Support
Prosthesis An artificial or substitute body part.
Pulmonary Pertaining to the lungs.
Pulmonary Artery The large artery that conducts deoxygenated blood from the right ventricle to the lungs.
Pulmonary Circulation The circulation of blood through the lungs for oxygenation. It is also known as the lesser circulation because the flow path is short and lower pressure is required for it to operate efficiently.
Pulmonary (Pulmonic) Valve A semilunar valve located between the right ventricle and the pulmonary artery that prevents backflow of blood into the the right ventricle.
Pyrolytic Carbon A carbon formed by breaking down a hydrocarbon gas at high temperatures (pyrolysis) into carbon and hydrogen molecules. Because the material is durable, strong and biocompatible, it has become the preferred material for mechanical heart valves.
Regurgitation See incompetence.
Right Atrium The right upper chamber of the heart, which receives deoxygenated blood from the systemic venous system.
Right Ventricle The right lower chamber of the heart, which receives deoxygenated blood from the right atrium and pumps it to the lungs via the pulmonary artery.
Sepsis An infection in the blood, commonly called blood poisoning.
Semilunar Literally, half-moon shaped, describing the characteristic shape of the leaflets of the aortic and pulmonary valves.
Stasis Regions of low blood flow or stagnation. Blood flow in stasis tends to activate the coagulation process.
Stenosis A narrowing of the heart valve orifice (opening), which prevents the valve from opening completely and decreases the blood flow through the valve. This means that the valve indicated has become so narrowed that it does not function normally.
Superior Vena Cava The large vein that delivers deoxygenated blood from the veins of the head and upper body to the right atrium.
Suture Surgical thread used for sewing tissue (including blood vessels) together.
Systemic Circulation The circulation of oxygenated blood from the left ventricle of the heart to all non-pulmonary systems and organs of the body. It is also known as the greater circulation because the flow path is long and higher pressures are required relative to the lesser (pulmonary) circulation.
Thrill A vibration in the heart, high in frequency and sustained. If a vibration is felt but no murmur is heard, the vibration is not called a thrill.
Thromboembolism A blood clot which circulates in the bloodstream and blocks a vessel.
Thrombogenic Causing (or having the potential to cause) the formation of a thrombus.
Thrombolytic Causing the breaking up or disintegration of a thrombus.
Thrombosis The formation of a blood clot in a blood vessel, a chamber of the heart, or on a natural or prosthetic heart valve.
Thrombus An attached blood clot. If it breaks away and blocks circulation in an artery, it becomes an embolus.
Tissue Valve Generally a replacement heart valve that is entirely or partly made from biological tissue. The tissue is usually of human, bovine (cow) or porcine (pig) origination.
Tricuspid Valve An atrio-ventricular valve located between the right atrium and the right ventricle that prevents backflow of blood into the right atrium.
Turbulence A fluid flow that is characterized by a disorderly and irregular eddying motion. Turbulence impedes flow, and highly turbulent flow in blood can cause red blood cell and platelet damage.
Warfarin An anticoagulant drug given orally. Also called Coumadin®.
Xenograft (Heterograft) A graft in which the donor and recipient of transplanted tissue are of different species (e.g., a pig valve used in a human)