When the heart fails: New artificial hearts and other technological tools help fight heart failure

Nearly five million Americans are affected by heart failure and the condition contributes to approximately 250,000 deaths every year. For many people with severe heart failure, the sole hope for extending life lies with a heart transplant. According to PinnacleCare Center of Excellence The Mayo Clinic, there is an average of approximately 4,000 people on the waiting list for a donor heart on any given day. But donor organs are scarce, with an annual supply of only about 2,000 hearts.

To supply patients with a tool that can help bridge the gap and extend life until a heart becomes available, doctors, engineers and other specialists invented a temporary mechanical replacement for the human heart known as the total artificial heart. Since the first total artificial heart was implanted in 1967, the technology has evolved, with artificial hearts becoming smaller and more reliable.

The art of artificial hearts

Most devices available today are only used in patients who are in imminent danger of death from heart failure and serve as what is known as a “bridge to transplant.” The CardioWest Temporary Total Artificial Heart (TAH-t) is the first and only FDA-approved device in this category. It is an air-driven pulsatile pump (it mimics the human pulse) that is placed in the patient’s chest and connected to the pulmonary artery and the aorta after the native heart is removed.

The air that powers the heart comes from a large console to which the patient is connected. Because of the console’s large size and the risk of infection at the sites where wires break the skin to connect to the console, the patient must remain in the hospital until a donor heart is found. The company has recently gotten approval in Europe for its portable pneumatic driver which allows stable patients to leave the hospital and move about.

A study published in The New England Journal of Medicine found that in clinical trials, patients implanted with the CardioWest TAH-t increased their odds of living another year from 31 to 70 percent when they are bridged to transplant. The benefit of receiving the artificial heart is that it allows blood to be more effectively circulated throughout the body, preventing organ damage and improving both quality of life and the likelihood of surviving until a donor heart becomes available.

In contrast, the AbioCor, which was approved by the FDA last year under a Humanitarian Device Exemption, is a permanent battery-powered artificial heart for use in patients with severe heart failure who are medically ineligible for the transplantation of a donor heart. Unlike other artificial hearts, the AbioCor is self-contained with no wires that break the skin and increase infection risk. The goal of this device in its current incarnation is to improve the quality of life for patients for the time they have remaining. Because the device is entirely contained within the patient’s body, those who are healthy enough can leave the hospital.

The longest survival to date with the AbioCor was 17 months. One drawback is the device’s relatively large size. It cannot fit into the chests of approximately 90 percent of women and many smaller men. The company is currently working on a next generation device that will be smaller and, its creators hope, will have the ability to extend life for five years.

Other innovations in the fight against heart failure

Far more common than artificial hearts, ventricular assist devices (VADs) help heart failure patients by allowing the ailing heart to rest while these small devices do the work. Most VADs are implanted into the patient’s abdomen and connected to a computer worn in a fanny pack. They allow patients to return to many of their regular activities and can serve as bridges to transplant and to improve quality of life for those who aren’t eligible for a transplant. A study of the devices’ effectiveness found that after two years, deaths were reduced 47 percent, raising the possibility that VADs could become a permanent treatment for heart failure in the future rather than simply a bridge to transplant.

One new device, the HeartMate II, is unique. Unlike other VADs that reproduce the pulsing action of the heart, this device is a continuous flow pump which means the patient has no pulse. In a study published last summer in The New England Journal of Medicine 75 percent of the sickest people who received the device lived for at least six months, an outcome better than other first-generation pumps.

Another innovation comes from CircuLite, which has developed a device it calls the Synergy Pocket Circulatory Assist Device. It’s a miniature implantable blood pump, the size of an AA battery that can be implanted under the skin using a minimally invasive technique. The device is designed to cut the risks associated with implanting a surgical device with traditional open surgery and provide long-term, partial circulatory support in patients with chronic heart failure.

The hearts of some patients with VADs have regained enough health to no longer be considered to be failing and the devices have been removed. Physicians believe that the recovery was made possible because the heart muscle was permitted to rest. “In a lot of ways, it's not unexpected,” says Dr. John Watson of the National Heart Lung Blood Institute (NHLBI) who was involved in a study to gauge the effectiveness of VADs. “One of the original ways of treating heart failure was with bed rest, and some people recovered. It's like putting a bone in a cast, giving the heart time to heal.” He cautions, however, that he believes recovery is the exception rather than the rule at this point.

Adds Dr. Eric A. Rose, Chairman of the Department of Surgery at Columbia University College of Physicians and Surgeons and Surgeon-in-Chief at Columbia Presbyterian Medical Center, “I think that LVAD (left ventricular assist device) usage will be analogous to kidney dialysis. When dialysis was first introduced in the 1960s, it was only viewed as a bridge to kidney transplantation. But as the technology developed, it's gotten to the point where people can live on dialysis for decades.”

Other researchers are exploring a much less high tech approach to heart failure treatment. Currently in a feasibility study at PinnacleCare Center of Excellence Johns Hopkins Hospital, the Paracor Ventricular Support System is a passive elastic wrap that applies gentle pressure to support the heart to help prevent further dilation and to encourage the heart to remodel into a smaller, more efficient heart.

PinnacleCare Members can turn to their Advocate and the Research Team to learn about the latest treatment options for heart failure and to explore clinical trials available in the U.S.