When hearts begin to fail, cardiologists often give the hearts a chance to keep working with ventricular assist devices. Threats of blood clots and infections persist because current devices have direct contact with blood, requiring that patients take anticoagulants and continuous monitoring. Because monitoring typically requires in-hospital care, technology that could allow out-of-hospital monitoring could have tremendous benefits in cost of care and patient lifestyles.
Scientists led by Ellen T. Roche of the School of Engineering and Applied Sciences, Harvard University have developed a soft robotic sleeve that encases the heart but does not come in contact with blood. The robotic sleeve has material characteristics similar to the muscle tissue surrounding the heart and the pulsing rhythm is controlled by a conventional pacemaker. Inside the sleeve compressed air powers silicon muscles that twist and compress the heart, as happens with natural heart muscles. Tests by the Harvard-led group showed increases of blood pumped from the left ventricle (cardiac ejection volume) in isolated tests outside a mammalian body and in adult pigs in cardiac arrest.
Much work remains before soft robotic heart sleeves are approved for use with human patients. In testing so far, the sleeves have been used in the labs with cases of complete cardiac arrest. Repeat and replicated studies are needed to show the reliability of the team’s findings, but in addition, the appropriateness of using the sleeve for longer terms needs to be evaluated.