A new technology could be a lifesaver for individuals with heart failure awaiting transplant
Currently, ventricular assist devices (VADs) can be used to improve the health of patients with end-stage heart failure awaiting a transplant.
VADs work by pumping blood from the heart and pushing it around the body. To work, the blood has to leave the confines of the blood vessels and travel through tubes and rotors.
Because of this contact with foreign material, the patient needs to take anticoagulants. These drugs can make VADs a viable solution, but they also increase the risk of stroke by 20 percent.
Besides VADs, cardiac sleeves are another option; they sit around the heart and squeeze it in order to replicate muscular contractions. These heart compression interventions are also far from perfect and, until recently, had been all but abandoned.
A team of biomedical engineers and clinicians from Harvard in Cambridge, MA, and Boston Children’s Hospital has designed and tested a robotic sleeve that twists and compresses the heart in the same way that healthy ventricles would.
Although the classical image of a robot is a solid structure capable of withstanding interstellar warfare, the robots of modern medical research are the polar opposite. Made from elastomers, fibers, and other filler materials, a new wave of so-called soft robots are able to interact intimately and delicately with human anatomy.
Made exclusively from non-rigid, biocompatible materials, this groundbreaking cardiac sleeve sits outside of the heart, removing the need for anticoagulants while minimizing infection risks. It uses pneumatically powered “air muscles,” called actuators.
The soft robotic actuators are essentially artificial muscles. The thin silicon sleeve is tethered to an external pump that uses air to power the actuators.
One section of the sleeve twists and the other squeezes, mimicking both ventricles of the heart. Earlier cardiac sleeves were limited in that they could only squeeze.
At this stage the concept was tested on pigs with the ability to restore the heart to 97 % of its original cardiac output.
Published in the journal Science Translational Medicineby Dr. Nikolay Vasilyev