Johns Hopkins Hospital has just been chosen as one of four hospitals in the nation to implant the new AbioCor, the first fully self-contained artificial heart.
Artificial hearts that are currently available have many shortcomings, the biggest of which is the high risk of infection after surgery. Because these hearts rely on an external power source, there are electrical cables running from the inside to the outside of the body, penetrating the skin.
The AbioCor implantable replacement heart is the first of its kind to employ transcutaneous transmission of energy: One pad under the skin receives the electrical current and a pad outside of the body delivers the energy. After the original surgical scar has healed, there are no permanent breaks in the skin.
John Conte, the associate director of cardiac surgery and the director of the Ventricular Assist Device Program at Hopkins Hospital, explained that the AbioCor "provides totally implantable support, so that the risk of infection goes away after [the patient] has recovered from the operation."
An additional benefit of the AbioCor is its greater overall durability, potentially lasting 18 months or longer. A newer model to be released later this year is designed to last up to five years.
Recent improvements to the Abiocor allow it to act as long-term support for patients with cardiomyopathies, a general weakening of the heart muscle, who are normally poor candidates for currently available devices. Total artificial hearts also eliminate any existing problems of the patient's original heart, such as arrhythmia, blood clots or leaking vales.
However, the full heart replacement is not without drawbacks. "By removing the entire heart, there is no backup if the device fails," said Ashish Shah, assistant professor of surgery and director of the Lung Transplant Program.
"Some patients have recovery of their native heart after months and years of conventional mechanical circulatory support and can have their devices removed. The total artificial heart eliminates this option."
Nevertheless, compared with traditional heart transplants, whereby the patient is put on a transplant list and is matched with a donor, a process that could potentially last months or even years, the AbioCor has a very promising future. "Once we reach a point where we have transcutaneous transmission of energy worked out, we won't be doing heart transplants for but a small percentage of the patients," Conte said.
"The biggest problem with a heart transplant is that you're trading one fatal disease for another," Conte said. Most transplant patients deal with organ rejection, suppression, infection and transplant coronary artery disease. Additionally, transplant patients have a 10-year survival rate of 50 percent, and most pay thousands of dollars each month for immunosuppressant medications. The AbioCor has the potential to eliminate these risks and costs.
Conte, who was instrumental in obtaining the AbioCor for the Hopkins program, sees Hopkins playing a large role in advancing the progress of artificial circulatory devices. "We are very active in the field of mechanical circulatory support, and we're one of the larger programs in the country, so we felt that is a great opportunity," he said.
Shah echoed these sentiments: "We hope that our experiences with the device will contribute the greater understanding of total artificial hearts in clinical practice and advance the field scientifically and clinically."
Artificial hearts first made headlines in 1982, when the first total artificial heart, the Jarvik-7, was successfully implanted. In 2001, the first AbioCor was implanted in a 58-year-old man named Robert Tools. Since then, only a handful of patients have received the AbioCor artificial hearts as surgeons and hospitals have learned more about the device.
The device was approved by the FDA in September 2006 under a special Humanitarian Device Exemption. This type of approval signifies that there are no alternative devices currently available to patients requiring this technology, and that the AbioCor is safe and likely to benefit the health of the patient.
