A ventricular assist device (VAD) is a battery-operated device that is designed to help either one or both ventricles of the heart pump blood. It does not replace the heart but instead helps the patient's own heart pump blood through the body. There are three groups of patients that may benefit from this therapy, including:

A VAD that supports only the left ventricle is known as a left ventricular assist device (LVAD), while a VAD that supports only the right ventricle is known as a right ventricular assist device (RVAD). Some patients may need both ventricles supported by a bi-ventricular assist device (BiVAD).

The first VADs were developed to be used on a temporary basis, usually for individuals waiting for a donor heart. There are now VADs that can be used on a permanent basis in patients who are not candidates for heart transplant. In general, there are three categories of VADs:

• Short term. These devices are typically used in high-risk patients who cannot sustain life over the long-term. They may be implanted in patients who cannot be weaned from the heart-lung machine or who have experienced a traumatic cardiac event that requires short-term help. The complication rate of these devices is relatively high, with ventricular arrhythmias occurring in more than 25 percent of patients with short-term LVADs. However, their use is justified because these patients would be unable to survive without the VAD.
  
  
• Intermediate term. These devices are the most commonly used VADs, frequently employed as bridges to transplantation among patients who are awaiting a heart transplant but deteriorate before a donor heart becomes available. These devices have been known to support patients for up to 500 days. The most common intermediate VAD has a 60 percent success rate, but unfortunately, it also has a high rate of complications, including bleeding, blood clots and infection. In these devices, the pump remains outside the body while the tubes that transport blood pass through the skin barrier, raising the risk of infection.
  
  
• Long term. These devices are designed for chronic or permanent use in patients with advanced heart failure. There are only two long-term VADs approved for use in the United States. They are designed to permit rehabilitation and hospital discharge after implantation, allowing patients to experience life outside a medical setting until their donor heart becomes available. They also may be used in patients who are not able to undergo a heart transplant.

In addition, a new VAD was recently developed that can be used in children and smaller patients. It is intended for use in children age 5 to 16 with severe left ventricular heart failure. This VAD may allow children to survive until a donor heart becomes available.

One potential benefit to VADs is possible rehabilitation for patients who are waiting for a donor heart. In up to 7 percent of cases, the heart function improves to the point where the VAD can be removed and no heart transplant is necessary. This improvement may occur because the VAD allows the heart muscle to rest and heal.

Patients who may not be appropriate candidates for a VAD include those who:

• Have severe disease in organs other than the heart, such as the lungs, kidneys or liver.
  
  
• Are in an advanced stage of cancer.
  
  
• Infections that do not respond to antibiotics.
  
  
• Have certain heart valve abnormalities.
  
  
• Had aortic dissection or aortic aneurysm.
  
  
• Have advanced aortic or peripheral vascular disease.
  
  
• Have artificial heart valves.
  
  
• Have a blood clotting or platelet disorder such as hemophilia.
  
  
• Are very short or thin with small body surface area.