Understanding Heart Valve Devices: Types, Materials, And Functionality

We all are aware that adequate circulation and supply of blood throughout the body is necessary for the proper functioning of organs, like the kidney, brain, lungs, heart, and others. Without proper circulation of blood to the entire body, delivery of oxygen and nutrients to the tissues and organs becomes challenging, increasing the chances of organ failure or dysfunction.

During blood flow to the heart and the rest of the body, our heart valves function as gateways that prevent the backflow of the blood. In case any of our heart valves are damaged or develop structural abnormalities that cause malfunction, an artificial valve may be needed to replace the diseased or damaged valve and restore proper blood flow throughout the body.

There are various types of artificial heart valve devices and different kinds of materials that are used to create them. Each device has its own benefits, drawbacks, and functionality. In this blog, we will discuss various types, materials, and functionality of heart valve devices, along with their benefits and features.

What Are Heart Valves?

Our heart consists of four valves, aortic valve, mitral valve, pulmonary valve, and tricuspid valve. The heart is a muscle responsible for pumping and supplying blood throughout the body, while the heart valves act as doors for the blood.

These doors (valves) open allowing blood to flow from one area of the heart to another area, and close as soon as the blood passes away to prevent backflow of blood. The opening and closing of the heart valves at the right time allow blood to flow in the right direction.

Types, Materials, And Functionality Of Heart Valve Devices

There are two main types of artificial heart valve devices:

  •  Mechanical heart valves
  • Bioprosthetic or tissue heart valves

A novel type of heart valve device that is still under development and research is known as a tissue-engineered heart valve.

1. Mechanical Heart Valves

Mechanical heart valves are a type of artificial valve made of strong, durable materials, like carbon, titanium, teflon, or cobalt. They are constructed with two leaflets and a metal ring enclosed by a knitted fiber ring. The mechanical valve is implanted in the heart by sewing the fiber ring at the place of the diseased or damaged valve.

The major benefit of mechanical valves is that they are durable, while its drawback is the chances of blood clot formation at the surface of the artificial mechanical valve. Hence, to prevent the development of blood clots, the patient may need to take anticoagulant medications, like warfarin for a lifetime, because blood clots can increase risks of heart attack and strokes.

2. Bioprosthetic Heart Valves

Bioprosthetic heart valves are also known as biological or tissue valves. As the name suggests, these valves are made of animal or human tissues. Bioprosthetic valves may be derived from animal tissues, like bovine (cow) tissue, porcine (pig) tissue, or equine (horse) tissue.

In contrast, bioprosthetic valves made of human tissues are derived from a donor human heart called homograft or allograft and then used as a replacement for the diseased valve. Bioprosthetic valve implantation can be done through minimally-invasive procedures or open heart surgery.

The advantage of bioprosthetic valves is that they don't require using lifelong anticoagulants, while its drawback is that they are relatively less durable than mechanical valves, and may cause structural valve deterioration. The patients may require re-operation within 10 to 20 years.

3. Tissue-Engineered Heart Valve

Tissue-engineered valves are a novel heart valve device, in the process of research and development. It is designed to eliminate the drawbacks of mechanical and bioprosthetic valves. The device is engineered with a combination of living cells and biomaterials that stimulates the function and structure of naturally-present heart valves that are diseased or damaged.

Tissue-engineered heart valves are made of two major components, including:

  •  Biomaterial Scaffold: It is the primary component of the tissue-engineered heart valve that provides structure, shape, and support to the diseased valves. They are made of biocompatible or biodegradable materials, like extracellular matrix or synthetic polymers.
  • Living Cells: The living cells are seeded into the biomaterials that proliferate within the Scaffold to function as the leaflet or supporting structure of the valve. The living cells can be taken from the patient's own cells or the donor cells.