Scientists Develop Fast-Pumping Artificial Foam Heart

Artificial heart
The artificial heart is made from a single piece of silicone. Ben Mac Murray

Scientists have developed a soft, foam-based artificial heart that can pump at a faster rate than any similar alternatives.

The proof-of-concept heart is made of flexible, porous silicone and is an example of soft robotics, which move by allowing compressed air to flow through the material, according to New Scientist magazine. Many of the current artificial hearts approved by the U.S. Food and Drug Administration (FDA), which tests medical devices, are hard devices that are attached to external pumps, such as the SynCardia Total Artificial Heart.

The research, published recently in the journal Advanced Materials, was led by Robert Shepherd, assistant professor of mechanical and aerospace engineering at Cornell University. The foam heart is attached to an external pump and coated with a thin layer of plastic to stop fluid from leaking out. Shepherd says the heart is an improvement on current models that have a number of components. "There's only one part that's on the inside of the body in our heart and none of it rotates or has any joints, it's just a single piece of molded material," says Shepherd. "We were surprised at how effectively our pump demonstration worked, but we are just now looking into practical uses as a biomedical device." The development of the material into a fully working artificial heart ready for transplant is some years away, he adds.

The researchers molded the material into a basic human heart shape in order to test it, but have only tested a two-heart chamber, whereas the real thing would need four chambers to mimic a human heart. They also found that the foam-based heart could tear if overinflated. The researchers said the material would be adapted to make it less susceptible to tearing.

Several other changes need to be made in order to make the material suitable for usage in an artificial human heart. "We need to make it pump at higher flow rates, which can simply be tuned by changing the tubing diameters we used," says Shepherd. "We also need to make it smaller so it is easier to insert into the body without creating huge incisions—that is very feasible since most of the soft heart's initial volume is air."

Cardiovascular disease causes more than four million deaths in Europe each year, according to the European Heart Network. At the end of 2013, there were 3,450 patients awaiting heart transplants in the European Union (EU), according to European Commission figures. Artificial hearts are devices that are designed to act as bridges toward heart transplantation but can also replace the heart permanently if transplantation is impossible. In 2012, 2,004 heart transplants took place in the EU, 34 percent of the total number of heart transplants conducted around the world. There have been around 1,400 artificial heart implants since 1969, according to SynCardia.

Shepherd says the team is working to develop the material into left ventricular assist devices (LVADs), which are currently used to assist people with weak hearts and can act as an interim before an artificial heart is implanted. The team hopes to have proved the material's usability as an LVAD by the end of the year, says Shepherd, before moving on to trying to develop the material into a full-blown artificial heart, though he says that is some years off.