Artificial Heart Valves By: Brian Volpe
What is it? An artificial heart valve is a mechanism that mimics the function of a human heart valve It’s used for patients with a heart valvular disease or have a damaged valve Heart valves are used to provide the heart with a unidirectional blood flow They act as pumps
Types of Artificial Heart Valves Mechanical- There are three types. The caged ball, tilting disk, and bileaflet Tissue(biological)- valves that are used from animals to implant them back into humans
History The first ever invented artificial heart valve was designed by Charles A. Hufnagel which was the caged-ball design On September 21, the first human was implanted with the ball and cage design Binet and associates, started using porcine aortic valves for humans The Bjork-Shiley valves was the first tilting- disc design to come out 1979-the beleaflet design was introduced which was composed of two semicircular leaflets that shifted open and closed
Mechanical Heart Valves All the types of mechanical heart valves are still in use today. Usually made of titanium or carbon which makes them strong and very durable Three types of mechanical heart valves
Tissue Heart Valves (biological valves) Using valves from other animals. The procine valve of a pig is the most comparable valve to a human. Xenotransplantation Pericardial valves: Biological valve tissue can be taken from a cow or horses pericardial sac and be sewed to a metal frame.
Advantages Mechanical heart valves: The biggest advantage is the durability. While the tissue heart valves are estimated to last about years, a mechanical heart valve can last 30 year Tissue heart valves: There is minimal blood regurgitation, minimal transvalvular pressure gradient, self repairing. Does not require and anti- coagulant drug.
Disadvantages Mechanical heart valves – In order to decrease the risk of blood clotting, the patient must take blood thinners. Some patients can hear their mechanical heart valve open and close. Tissue heart valves – Wear, there is a small possibility that the body will reject the valve, inability to implant them into infants and children.
Figure. Algorithm for selecting a valve procedure. El Oakley R et al. Circulation 2008;117: Copyright © American Heart Association
Implanting Both mechanical and tissue heart valves require open heart surgery It’s more common in tissue valves for a re- operation Complete recovery from surgery could be a couple of weeks to several months Currently: 55% mechanical valves 45% tissue valves
Future of heart valve replacement Polymeric Heart Valves - Scientists are looking more into polymer materials for heart valves because it’s easy to fabricate, has a large range of polymer properties, and durability. Tissue engineered heart valves- Obtaining the number of types of cells for tissue valves, lack of scaffold material
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