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 1952- The first ever invented artificial heart valve

was designed by Charles A. Hufnagel which was the caged-ball design

1960- On September 21, the first human was implanted with the ball and cage design

Binet and associates, started using porcine aortic valves for humans

1969- 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 10-15 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;117:253-256

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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