Image: A soft artificial heart made of silicon mimics natural function (Photo courtesy of ETH).
A completely soft, pneumatically driven artificial heart made of silicone elastomers beats almost like a human heart, according to a new study.
Developed by researchers at ETH Zurich (Switzerland) and Deutsches Herzzentrum Berlin (DHZB; Germany), the soft total artificial heart (sTAH) is similar in form to the human heart, but consists of only two ventricles, which are separated not by a septum but by an additional chamber that is inflated and deflated by pressurized air. The function of the inner chamber is to replace the muscle contractions of the natural human heart. The sTAH was created from silicone using a 3D-printed, lost-wax casting technique, and weighs 390 grams, with a volume of 679 cm3.
The sTAH was evaluated using a hybrid mock circulation model under various conditions, generating physiologically shaped signals of blood flow and pressures. When operated at 80 bpm, the soft heart achieved a blood flow of 2.2 L/min against an afterload systemic vascular resistance of 1.11 mm Hg, with mean pulmonary venous pressure fixed at 10 mm Hg. A resulting aortic pulse pressure of 35 mm Hg was measured, with a mean aortic pressure of 48 mm Hg. The study was published on July 10, 2017, in Artificial Organs.
“The soft artificial heart fundamentally works and moves in a similar way to a human heart. However, it still has one problem; it currently lasts for about only 3,000 beats, which corresponds to a lifetime of half to three quarters of an hour,” said study co-author Anastasios Petrou, MSc, a doctoral student at the ETH Product Development Group. “After that, the material can no longer withstand the strain. As a mechanical engineer, I would never have thought that I would ever hold a soft heart in my hands.”
A functional artificial heart remains one of the long-sought holy grails of modern medicine, as it would dramatically lower the need for heart transplants. But straightforward emulation of the anatomy of the human heart with synthetic materials is difficult due foreign-body rejection, the need for external power sources, and other complications that limit their lifespan and that of the human recipients.
Deutsches Herzzentrum Berlin