College of Medicine develops new heart assist device

A new device developed in part by the University's College of Medicine may help heart patients live longer, more comfortable lives.

Alan Snyder, associate professor of bioengineering and senior research associate in surgery, spoke last week to the University Board of Trustees about the history of artificial heart research.

He also spoke about ongoing attempts to make devices that help pump blood for heart patients more reliable.

The College of Medicine, in conjunction with Arrow International Inc., has developed a new left ventricular assist device (LVAD), which it hopes will not only be more effective, but safer for patients, Snyder said. It is also continuing work on a total artificial heart, he added.

"This is what we said we wanted to do 20 years ago," Snyder said of the Arrow LVAD. "LVADs have taken over the job of bridging patients over to implant surgery."

Tens of thousands of people must depend on either a totally artificial heart or a LVAD to support them until a heart is made available for transplantation, or as rehabilitation tools after surgery, Snyder said.

Traditional ventricular assist devices, such as the TCI air-driven HeartMate, which is now being used by 11 Hershey Medical Center patients, have a shopping cart-sized driver that fuels the ventricular pump. Although the driver is portable, it is difficult for a patient to move about with ease, said Dawn Christensen, coordinator of the Ventricular Assist Device Program at the University's Hershey Medical Center.

The new LVADs are much more convenient for patients because the energy source is contained in a small pack worn outside the body. However, the Arrow LVAD is the only one whose battery pack does not require the wires to break through the surface of the skin.

Others, such as the TCI wearable LVAD, penetrate the skin, leaving patients more susceptible to infections, Christensen said.

The Arrow LVAD rests inside the patient's abdominal area and has two tubes that pump blood through the heart. The left ventricle is supported because it is the heart's main pump.

The Arrow LVAD is supported with electricity that flows through the skin by way of two coils.

The device also has an internal back-up battery, so a patient is able to remove the external battery pack to get dressed or take a bath, Snyder said.

Christensen said LVADs have demonstrated reliability in the past.

"Basically, 75 percent make it to transplant," she said. A person has been supported on a LVAD for as long as 726 days, she said.

Although none are commercially available, the Arrow LVAD should be on the market after rigorous lab testing, Snyder said. In that time, it will have to survive a two-year lab durability test, which imitates the natural pumping of the heart.

The average heart beats more than 30 million times a year, Snyder said, making this is a challenging test.

Pending Food and Drug Administration approval, the Arrow LVAD should be available commercially by the year 2000, Snyder said.