Every year about 2,100 people receives heart transplants in the United States, while 5.7 million suffer from heart failure. Given the scarcity of available donor hearts, clinicians and biomedical engineers from Boston Children’s Hospital and Harvard University have spent several years developing a mechanical alternative.
Their proof of concept is reported in Science Translational Medicine: a soft robotic sleeve that is fitted around the heart, where it twists and compresses the heart’s chambers just like a healthy cardiac muscle would do.
Pigula and his collaborators have designed a device that attaches to and snugly hugs the outside of the heart without having any contact with blood. The soft robotic sleeve mimics the heart’s natural compression motion using only non-rigid, biocompatible materials.
Their tests were done in pig hearts given their similar size and structure to human hearts show that the device restores acutely failing hearts to 97 percent of their original cardiac output.
“This work represents an exciting proof-of-concept result for this soft robot, demonstrating that it can safely interact with soft tissue and lead to improvements in cardiac function,” says Conor Walsh, PhD, the John L. Loeb Associate Professor of Engineering and Applied Sciences at Harvard SEAS and a Core Faculty Member at the Wyss Institute. Walsh, a soft robotics expert, co-led the study with Pigula.
Utilizing pneumatically powered “air muscles,” different parts of the device bend and flex via remotely controlled actuators that initiate the movement, mimicking the orientation of a heart’s contracting muscle fibers. One part of the device takes care of the twist, and another, the squeeze.
“The soft robotic actuators are essentially artificial muscles,” says Nikolay Vasilyev, MD, a staff scientist in cardiac surgery research at Boston Children’s Hospital and co-author on the recent study. “In this sense, the robotic sleeve mimics both ventricles of the heart.”
The soft robotic heart sleeve also contains sophisticated sensing abilities that measure pressure at specific points on the heart’s surface.
“The cardiac field had turned away from the idea of developing heart compression instead of blood-pumping VADs due to technological limitations,” says Pigula. “But now, with advancements in soft robotics, it’s time to turn back. Most people with heart failure still have some function left. One day. the robotic sleeve may help their heart work well enough that their quality of life can be restored.”
Citation: Ellen T. Roche, Markus A. Horvath, Isaac Wamala, Ali Alazmani, Sang-Eun Song, William Whyte, Zurab Machaidze, Christopher J. Payne1, James C. Weaver, Gregory Fishbein, Joseph Kuebler, Nikolay V. Vasilyev, David J. Mooney, Frank A. Pigula and Conor J. Walsh. “Soft robotic sleeve supports heart function.” Science Translational Medicine 2017 vol: 9 (373).
Adapted from press release by Boston Children’s Hospital.