This Soft Robot Saves Failing Hearts By Mimicking Cardiac Muscle

Scientists have developed an implantable robotic device that helps the heart continue beating even after cardiac failure.

"We've combined rigid bracing with soft robotic actuators to gently but sturdily help a diseased heart chamber pump blood effectively," says cardiac surgeon Nikolay Vasilyev a researcher in cardiac surgery at Boston Children’s Hospital.

Soft robotic actuators are artificial muscles designed and programmed to perform lifelike functions and motions. Recently, these devices have emerged as a better alternative to the more rigid products used in the biomedical field.

Researchers at Boston Children’s Hospital have created a proof-of-concept soft robotic sleeve that can support a failing heart. Usually, in pediatric patients at the hospital, heart issues are a culmination of many issues and usually involve problems in both ventricles separately. To combat this problem, the doctors working on the device came up with a solution.

“We set out to develop new technology that would help one diseased ventricle, when the patient is in isolated left or right heart failure, pull blood into the chamber and then effectively pump it into the circulatory system,” says Vasilyev.

Vasilyev and his colleagues ( researchers from Boston Children’s, the Harvard John A. Paulson School of Engineering and Applied Sciences and the Wyss Institute for Biologically Inspired Engineering at Harvard University) who worked on the project have published the working behind their soft robotic solution in a paper online in Science Robotics today.

The Pump Challenge

The problem with current pumps used in medic practice is the exposition of blood to an unnatural surface, as the pump propels blood through itself. Therefore Vasilyev looked at actuators.

“Running blood through a pump always requires a patient to be placed — permanently — on anticoagulant medication to prevent blood clotting,” Vasilyev says, who is senior author on the paper. “It can be very difficult to keep the right balance of medication, especially in pediatric patients, who are therefore at risk of excessive bleeding or dangerous clotting.”

External actuators placed outside the heart squeeze blood through the chamber, minimising the need for anticoagulants.

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“We’ve combined rigid bracing with soft robotic actuators to gently but sturdily help a diseased heart chamber pump blood effectively,” Vasilyev says.

This brace component is inserted using a needle placed into the heart’s intraventricular septum or wall of tissue between the heart’s chambers.

“With the use of classic left ventricular assist devices, there are patients who experience a septum shift towards the right side and subsequent ballooning of the right ventricle, which can cause secondary right heart failure,” Vasilyev says. “Here, the rigid brace keeps the septum in its original position, protecting the healthy right side of the heart from the mechanical load of the left ventricular assistance.” Most VADs (ventricular assist devices) never involve the septum.

Upon testing the device on animals, they noticed that the soft robotic system helped a diseased ventricle’s ability to pump blood. It also helped to draw it out.

“As the actuators relax, specially-designed elastic bands help return the heart’s wall to its original position, filling the chamber sufficiently with blood,” Vasilyev says. Now the team is working on modifying their system to perhaps start testing it on human subjects, including improving its portability.