For a sick patient in need of a heart transplant, the agonizing wait for a donor meant living at the hospital, tethered to a washing machine-sized device that powered an artificial heart. But this summer, an artificial heart company announced the development of a portable, backpack-sized driver that allowed three patients to wait for transplants from home.
I spoke recently with Steve Langford of SynCardia Systems, manufacturer of the temporary Total Artificial Heart and the new, portable Freedom Driver, about how patients whose hearts are no longer pumping enough blood can have their ventricles replaced by a device powered by a driver carried over the shoulder.
How does the Total Artificial Heart work?
The SynCardia Total Artificial Heart is an air-powered device. It requires attachment to an external controller, which actually inflates internal membranes inside the [artificial] heart. When the internal membranes are inflated, it pushes the blood out of the [artificial ventricles]. We use valves inside of the [artificial] heart to control the direction of the blood flow. We currently have a 13.5-pound Freedom drive system which enables patients [who are in stable condition and meet the criteria] to be enrolled in an FDA study. (The study is designed to demonstrate that the Freedom driver is a suitable pneumatic driver for stable Total Artificial Heart patients and can be used safely at home.) Patients, when they have the artificial heart, become very well, very quickly. When they are attached to this 13.5-pound driver, it's like having a small backpack or a book bag that they can carry with them. It enables them to have complete mobility and a virtually-normal lifestyle.
How did we move from a washing machine-sized device to a backpack-sized machine?
There's been a lot of advancement in technology. The large machine was developed in the 1980s and used the most recent technology that was available at that time. We now have transducers and electronics that are much smaller in size. All the patient safety monitoring systems are still available. But because of the reduced size in electronics, we're able to offer that in a much smaller footprint.
The human impact is very significant. The number of [heart] donors has remained flat since about the 1980s. There are between 2,000 and [2,200] donors each year. There are more and more surgeons finding patients that are qualified to receive a heart transplant. The demand has gone up, but the supply has remained relatively flat. Patients who are waiting for transplant have to wait longer and longer until they receive a match compatible with them. The impact with the smaller drive system is that now while the patient is waiting their heart transplant, they will be able to go home and have a normal life.
In addition to having longer time to wait until they receive the right match, [patients who use the Total Artificial Heart] are in better health. When they receive a transplant, their nutrition level is balanced, their muscle tone is there. The fantastic thing with the artificial heart is that it eliminates the other factors that accompany heart disease.
What's the next step for the Total Artificial Heart?
Conditional approval [from the FDA means] that we have permission to conduct a clinical trial. As we enroll patients in this clinical trial [of the Freedom driver], we'll be collecting data [to submit to FDA. Once the study is completed, FDA will review these data and determine if the Freedom driver should receive approval for commercial use in the U.S.]
Image, top: Freedom Driver with Total Artificial Heart
Image, bottom: Steve Langford