This is a mitral artificial heart valve manufactured by Shiley Incorporated. It has a carbon tilting-disk which opens 60 degrees, retaining struts, and a Teflon fabric suture ring.
Biomedical engineer Donald P. Shiley (1920-2010) and Viking O. Björk (1918-2009) professor of thoracic and cardiovascular surgery at the Karolinska Institute in Stockholm, Sweden, began working on their artificial valve around 1968. They were intent on developing an improved tilting-disk valve that would work in a narrow aortic root. This aortic valve is a spherical-shaped tilting carbon disk with a woven Teflon sewing ring.
This Björk-Shiley 60-degree mitral Convexo-Concave heart valve has a tilting carbon disk and a Teflon fabric suture ring. The valve ran into problems when the weld joint fractured. This problem was resolved with a free-floating disk.
Tissue valves such as this Hancock Mitral Valve must be stored in a sealed liquid (formaldehyde) filled container until implantation.
Both porcine (pig) and bovine (cow) tissue are used to make xenograft (transplant from one species to another) valves. Porcine valves utilize the actual valve from the pig, whereas bovine valves are cow tissue that is manipulated into the shape of a valve.
The Hancock Mitral-Tricuspid is a porcine tissue valve, and has a pliable sewing ring. Advantages of having a tissue valve is that one need not take blood-thinner/anticoagulant medication after receiving the valve. For the majority of tissue valve patients, taking an aspirin a day is sufficient anticoagulation therapy. A disadvantage is that they are less durable and will need to be replaced within the patient's lifetime, typically 10 to 15 years, often less in younger patients. Because valve replacement surgery carries a significant risk of death, patient life expectancy is a major criterion in considering a tissue valve. Tissue valves can become hardened, or calcified, over time and there is a rare risk of tissue valve failure or infection.
This valve was manufactured by Extracorporeal Medical Specialties, Inc., which operates as a subsidiary of Johnson & Johnson.
Tissue valves such as this must be stored in a sealed liquid (formaldehyde) filled container until implantation.
Both porcine (pig) and bovine (cow) tissue are used to make xenograft (transplant from one species to another) valves. Porcine valves utilize the actual valve from the pig, whereas bovine valves are cow tissue that is manipulated into the shape of a valve.
The Hancock Mitral-Tricuspid is a porcine tissue valve, and has a pliable sewing ring. Advantages of having a tissue valve is that one need not take blood-thinner/anticoagulant medication after receiving the valve. For the majority of tissue valve patients, taking an aspirin a day is sufficient anticoagulation therapy. A disadvantage is that they are less durable and will need to be replaced within the patient's lifetime, typically 10 to 15 years, often less in younger patients. Because valve replacement surgery carries a significant risk of death, patient life expectancy is a major criterion in considering a tissue valve. Tissue valves can become hardened, or calcified, over time and there is a rare risk of tissue valve failure or infection.
This valve was manufactured by Extracorporeal Medical Specialties, Inc., which operates as a subsidiary of Johnson & Johnson.
The Hall-Kaster artificial heart valve has a pivotal Pyrolyte disk design, and a titanium cage. The sewing ring is covered in woven Teflon. A hole in the center of the disk is held in place by a central strut and two smaller struts emanating from the outer flange. Introduced in 1977, the Hall-Kaster valve was manufactured by Medtronic, and the name was later changed to the Medtronic-Hall heart valve.
The St. Jude artificial heart valve is a floating bileaflet valve with pivots near the central axis. The valve is made of pyrolyte carbon, a very durable and biocompatible material, and the cuff is made of Dacron. The orifice ring is made of machined graphite coated with pyrolytic carbon. The two leaflets are made of tungsten impregnated with graphite.
After successful tests in calves, the first human implantation occurred in October 1977. Over a twelve month period, twenty-four patients received implants of the St. Jude valve in the aortic and the mitral positions.
Manny Villafaña, the son of Puerto Rican immigrants founded St. Jude Medical Inc. in 1976. Villafaña had been approached by Xinon C. Posis, an engineer, and cardiologist Demetre Nicoloff of the University of Minnesota to test their design for a leaflet artificial heart valve. Villafaña and his engineers helped redesign the hinges.
This is a teaching model of an Omniscience aortic artificial heart valve. It is 23mm and it has a titanium cage and Pyrolyte disk.
In an article which appeared in the Annals of Thoracic Surgery, the “Evolution of Mechanical Heart Valves”, Richard DeWall refers to the Omniscience valve as a “direct descendant” of the Lillehei-Kaster free-floating valve prosthesis.
Thoracic and cardiovascular surgeon Viking O. Björk (1918-2009) had experience with the implantation of many different artificial heart valves at the Karolinska Institute in Stockholm, Sweden, before he teamed up with biomedical engineer Donald P. Shiley (1920-2010). Together they designed a new heart valve prosthesis. This aortic artificial valve was a spherical-shaped tilting carbon disk with a woven Teflon sewing ring. They began testing their valve in 1968 and were ready for the first human implantation in January 1969.
Description
Viking Bjork (1918-2009) was a thoracic and cardiovascular surgeon who had experience with the implantation of many types of artificial heart valves at the Karolinska Institute in Stockholm, Sweden. Donald P. Shiley (1920-2010), an American biomedical engineer. Working together, the two men designed a tilting disc heart valve—which, unfortunately, fractured when implanted in at least 389 people. Later models proved much more robust. Shiley Inc. donated this improved example to the Smithsonian in 1985.
Ref: Roxane Arnold, “Inventor at 60 Proves You Gotta Have Heart,” Los Angeles Times (June 16, 1981), p. E1, E2, and E4.
Barry Meier, “Designer of Faulty Heart Valve Seeks Redemption in New Device,” New York Times (April 17, 1990), p. C1.
“Donald P. Shiley dies at 90; co-inventor of Bjork-Shiley heart valve,” Los Angeles Times (Aug. 7, 2010), p.