What Is a Ventricular Assist Device?

A ventricular assist device (VAD) is a mechanical pump that's used to support heart function and blood flow in people who have weakened hearts.

The device takes blood from a lower chamber of the heart and helps pump it to the body and vital organs, just as a healthy heart would. (For more information about how the heart pumps blood, see the Diseases and Conditions Index How the Heart Works article.)

A VAD may be used if one or both of the heart's lower chambers, the ventricles (VEN-trih-kuls), don't work properly.

Overview

You may benefit from a VAD if your ventricles don't work well due to heart disease. A VAD can help support your heart:

• During or after surgery, until your heart recovers.
• While you're waiting for a heart transplant.
• If you're not eligible for a heart transplant. (A VAD can be a long-term solution to help your heart work better.)

The basic parts of a VAD include: a small tube that carries blood out of your heart into a pump; another tube that carries blood from the pump to your blood vessels, which deliver the blood to your body; and a power source.

The power source is connected to a control unit that monitors the VAD's functions. The control unit gives warnings, or alarms, if the power is low or if it senses that the device isn't working right.

Some VADs pump blood like the heart does, with a pumping action. Other VADs keep up a continuous flow of blood. With a continuous flow VAD, you might not have a normal pulse that can be felt, but your body is getting the blood it needs.

Types of Ventricular Assist Devices

The two basic types of VADs are a left ventricular assist device (LVAD) and a right ventricular assist device (RVAD). If both types are used at the same time, they may be called a biventricular assist device (BIVAD). However, a BIVAD isn't a separate type of VAD.

The LVAD is the most common type of VAD. It helps the left ventricle pump blood to the aorta. The aorta is the main artery that carries oxygen-rich blood from your heart to your body.

RVADs usually are used only for short-term support of the right ventricle after LVAD surgery or other heart surgery. An RVAD helps the right ventricle pump blood to the pulmonary (PULL-mun-ary) artery. This is the artery that carries blood to the lungs to pick up oxygen.

Both an LVAD and RVAD (sometimes called a BIVAD) are used if both ventricles don't work well enough to meet the needs of the body. Another treatment option for this condition is a total artificial heart.

VADs have two basic designs. A transcutaneous (tranz-ku-TA-ne-us) VAD has its pump and power source located outside of the body. Tubes connect the pump to the heart through small holes in the abdomen. This type of VAD may be used for short-term support during or after surgery.

Transcutaneous Ventricular Assist Device

The image shows a transcutaneous BIVAD and how it's connected to the heart.

An implantable VAD has its pump located inside of the body and its power source located outside of the body. A cable connects the pump to the power source through a small hole in the abdomen.

Implantable VADs mainly are used when you're waiting for a heart transplant or as a long-term solution if you're not a transplant candidate.

Implantable Ventricular Assist Device

Figure A shows the location of the heart and the typical equipment needed for an implantable LVAD. Figure B shows how the LVAD is connected to the heart.

The design and type of VAD your doctor recommends will depend on your overall health, how long you're expected to need the device, and other factors.

Outlook

Until recently, VADs were too big to fit in many people's chests, especially women. Only people who had large chests could get one.

Now implantable VADs can fit in most adults and even some older children. Devices small enough for young children aren't yet available, but they're being developed.

Researchers have made advances in how well VADs work and how much they improve people's quality of life. In the past, VADs mostly were used for people who had end-stage heart failure. Now VADs also can help people who have earlier stages of heart failure.

September 2009