The heart contains four one-way valves that open and close in sync with heart contractions. Malformation of a heart valve or damage acquired through disease sometimes necessitates heart valve replacement. A poorly functioning valve may be replaced with a mechanical prosthetic heart valve or a bioprosthetic valve, which contains both artificial and biological material. Various types of mechanical and bioprosthetic heart valves utilize different materials and mechanics to optimize the performance and durability of the device.
Porcine Stented Valve
A porcine stented valve is a bioprosthetic replacement valve. It is composed of a heart valve procured from a pig mounted over a man-made frame, or stent, which is sewn into place within the heart. The Cleveland Clinic reports that porcine stented valves may be used to replace damaged aortic or mitral valves. The mitral valve separates the upper and lower chambers of the left side of the heart. The aortic valve controls the outflow of blood as it leaves the heart for distribution to the body organs and tissues.
Bioprosthetic valves, including the porcine stented valve, closely resemble the natural heart valves, notes the University of Southern California Cardiothoracic Surgery Department. These valves, however, do not last as long as a mechanical valve. Lack of long-term durability can be a drawback of bioprosthetic heart valve use for patients requiring heart valve replacement surgery at a young age.
Pericardial Bioprosthetic Valve
A pericardial bioprosthetic valve utilizes heart tissue from a cow or horse mounted over a man-made framework to construct a replacement heart valve. A ring at the base of the valve is used to sew the valve in place. A pericardial bioprosthetic valve may be used to replace a diseased aortic or mitral valve.
The Heart Foundation points out that people who receive a bioprosthetic heart valve generally do not require life-long treatment with blood thinners, or anticoagulants. This is a potential advantage of the bioprosthetic heart valves over mechanical heart valves, which require ongoing anticoagulant therapy after placement of the prosthesis.
Bileaflet Mechanical Valves
Bileaflet mechanical valves are composed entirely of made-made materials. An outer ring houses two semicircular flaps, which open and close with the contractions of the heart. In a 2002 review article published in the journal "Heart," Dr. Peter Bloomfield reports that bileaflet mechanical heart valves are the most commonly implanted heart valves worldwide.
Mechanical valves, such as the bileaflet valve, offer the advantage of long-term durability. Lifelong anticoagulant therapy, however, is necessary to reduce the risk of blood clot formation. Despite anticoagulant therapy, the presence of an aortic or mitral mechanical valve pose a small risk for blood clot-induced stroke, reports the Society of Thoracic Surgeons.
