Photo credit: © 2021 EPFL / Yoan Civet.
In January of this year, the EPFL engineers announced their concept of a new type of cardiac support system in Advanced Science, which works without rigid metal components. It’s made up of a soft, artificial muscle wrapped around the aorta that can narrow and widen the vessel, which ultimately improves the aorta’s natural function and helps the heart pump blood to the rest of the body.
Now EPFL engineers, led by Yves Perriard from the Laboratory of Integrated Actuators, in collaboration with the University of Bern, have successfully implanted their first artificial tube muscle in vivo in a pig. During the four-hour operation, her cardiac assist device maintained 24,000 pulsations, 1,500 of which were artificially activated by the enlarged aorta.
The feat unlocked the remaining CHF 8 million of CHF 12 from the Werner Siemens Foundation to develop artificial muscles in a more general way.
“We have just delivered the world’s first proof of concept by successfully implanting our cardiac device in a live pig,” explains Perriard. “We are pleased that, thanks to the support of the Werner Siemens Stiftung, we can drive the next round of projects.”
At the end of 2017, the engineers were promised a donation of CHF 12 million from the Werner Siemens Foundation to set up a center for artificial muscles at EPFL based on scientific advances such as this latest proof of concept.
The additional funds will be used for the next phases of the project, including the development of artificial muscles for the treatment of other human diseases, such as artificial sphincters, in collaboration with the University of Bern, which could for example relieve urinary incontinence or restore control of facial expression together with the University of Zurich.
Next generation heart technology
Current heart technology requires the heart to be connected directly to a pump, which means invasive heart surgery. In addition, traditional pumps use rigid mechanical systems with a propeller to get the blood flowing, but which also destroy red blood cells, making them an unsustainable solution.
The novel cardiac device proposed by EPFL engineers does not manipulate the heart directly, but the aorta. The concept calls for a dielectric elastomer actuator (DEA) – a polymer that converts electrical energy into mechanical work – to place the aorta near the aortic valve. By applying an electrical voltage to your device, the actuator artificially constricts and expands the aorta and acts like a tubular muscle that mimics the natural function of the aorta.
“Our artificial aorta mimics the way blood vessels constrict and relax to move blood through the circulatory system. The difference is that the natural action of the aorta is passive due to the blood pressure, while our device is controlled by an external voltage, ”explains Yoan Civet from EPFL’s Integrated Actuators Laboratory. “With the help of our artificial aorta, the heart uses less energy to circulate the same amount of blood.”
Civet continues: “Our DEA is not a stand-alone pump. The heart gets the function of the DEA by providing the arterial pressure, and in return the DEA supports the heart by allowing the blood to pump more efficiently. “
Perriard explains: “Our device is minimally invasive because we do not touch the heart directly. In principle, it also conserves red blood cells because, unlike conventional methods, it does not contain any rigid metallic components. “
There are still many challenges ahead
Perriard and his team are excited about the success of their latest cardiology achievement, but they are also aware of their reservations.
For example, the current version of their DEA that is placed on the aorta may not have metallic components, but it still contains rigid plastic components that are used to connect the device to the aorta.
Also, the DEA should ideally be placed around the aorta, but this has yet to be achieved. The engineers suggest that they need to find a solution that does not involve severing the aorta in order to implant their device. “Maybe the solution is to find a way to get the aorta to stick to our device,” Perriard explains.