Researchers at Boston Children’s Hospital have developed a novel robotic cardiac assist device designed to assist patients with one-sided heart failure. The device combines soft actuators with a rigid brace that penetrates into the heart’s intraventricular septum, to provide gentle but robust pumping assistance to just one side of the heart, without disturbing the activity of the other side.
Soft robotic components have significant potential in minimally invasive cardiac assist devices that help the failing heart to pump by squeezing it from the outside. Unlike conventional ventricular assist devices, this approach does not require the device to have significant contact with the blood, reducing the risk of clotting and the need for anticoagulant therapy.
Medgadget recently reported on a soft sleeve that can envelope the failing heart and squeeze it, augmenting cardiac output. But what about one-sided heart failure, where just one ventricle is struggling to pump enough blood? This type of heart failure is more common in some pediatric patients, in which a congenital condition can cause failure of either the right or left ventricle, but not both.
In that instance, squeezing the entire heart could actually interfere with the pumping of the healthy ventricle, and a wraparound sleeve might not be suitable. To address this, some of the researchers behind the soft sleeve have come up with a new device that targets just one ventricle.
“We’ve combined rigid bracing with soft robotic actuators to gently but sturdily help a diseased heart chamber pump blood effectively,” says Nikolay Vasilyev, a researcher involved in the study. The rigid brace is implanted into the intraventricular septum, and provides resistance against soft actuators that cup the surface of the affected ventricle.
When the actuators expand, they push against the ventricular wall and pull against the septal brace, causing compression in the ventricular chamber, without affecting the other side of the heart. “As the actuators relax, specially-designed elastic bands help return the heart’s wall to its original position, filling the chamber sufficiently with blood,” says Vasilyev.
“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,” says Vasilyev. “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.”
The research team has tested the device in an animal model and it significantly enhanced the ability of a diseased ventricle to eject blood. Now, the team is working to modify the device so that it is suitable for human patients.
Study in Science Robotics: Soft robotic ventricular assist device with septal bracing for therapy of heart failure…