Bridging the Gap to Transplant: Introducing the Soft Artificial Heart

As of the date this article was written, there are currently 3,941 individuals listed on the waiting list for a heart transplant, according to the United Network for Organ Sharing. Of these, some are reliant on the implantation of artificial heart pumps to keep their bodies alive until a suitable organ becomes available.

Two common artificial heart devices in use today are the Total Artificial Heart (TAH) and Ventricular Assist Devices (VADs). You can see what a Total Artificial Heart looks like depicted below.

Sourced from The National Heart, Lung, and Blood Institute. With a TAH, tubes leave the body through the abdomen and are attached to a power console, which the patient must carry with them at all times.

Complications associated with these devices include mechanical problems evolving from the structure of the pump itself, as well as an increased risk of stroke and bleeding emergencies due to anticoagulation therapy.

A new technology developed by researchers at ETH Zürich may drastically change the scope of artificial heart devices. Doctoral student Nicholas Cohrs and colleagues, under the supervision of Wendelin Stark — professor at the Institute for Chemical and Bioengineering at ETH, have developed a soft artificial heart that is directly modeled after its biological counterpart. With this new device, they aim to reduce some of those aforementioned complications.

The soft artificial heart is composed of silicone and is 3D-printed using a lost-wax casting technique. Using silicone eliminates concerns regarding the durability of metals and plastics inside the body. Its anatomy is similar to that of an organic heart; it has both a left and right ventricle. Rather than a septum between them, however, the soft artificial heart boasts a third chamber which acts as the cardiac muscle tissue. Inflating and deflating this third chamber with pressurized air results in blood flow between the ventricles — in essence, a contraction. You can see the heart in action here:

Video: ETH Zürich

While this is incredible to watch, this model is far from ready for use in patients. Currently the heart can only sustain about 3,000 beats, equating to a lifetime of only 30–45 minutes. “This was a simple feasibility test,” says Cohrs, “Our goal was not to present a heart ready for implantation, but to think about a new direction for the development of artificial hearts.”

In this, they have certainly succeeded.

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