Soft robot wraps around heart to get it pumping again
A customisable soft robot that fits around a heart to help it beat has been developed by researchers in the USA at Harvard University and Boston Children’s Hospital.
The device potentially opens new treatment options for people suffering from heart failure and has been shown to restore acutely failing pig hearts to 97 per cent of their original cardiac output.
The soft robotic sleeve twists and compresses in sync with a beating heart, augmenting cardiovascular functions weakened by heart failure.
Unlike currently available devices that assist heart function, Harvard’s soft robotic sleeve does not directly contact blood, which reduces the risk of clotting and eliminates the need for a patient to take potentially dangerous blood thinner medications.
The device may one day be able to bridge a patient to transplant or to aid in cardiac rehabilitation and recovery.
“This research demonstrates that the growing field of soft robotics can be applied to clinical needs and potentially reduce the burden of heart disease and improve the quality of life for patients,” said Harvard’s Ellen T Roche.
“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.”
Heart failure affects 41 million people worldwide. Today, some of the options to treat it are mechanical pumps called ventricular assist devices (VADs), which pump blood from the ventricles into the aorta, and heart transplant. While VADs are continuously improving, patients are still at high risk for blood clots and stroke.
To create an entirely new device that doesn’t come into contact with blood, Harvard researchers took inspiration from the heart itself.
The thin silicone sleeve uses soft pneumatic actuators placed around the heart to mimic the outer muscle layers of the mammalian heart. The actuators twist and compress the sleeve in a similar motion to the beating heart (see picture below).
The device is tethered to an external pump, which uses air to power the soft actuators.
The sleeve can be customised for each patient, said Roche. If a patient has more weakness on the left side of the heart, for example, the actuators can be tuned to give more assistance on that side. The pressure of the actuators can also increase or decrease over time, as the patient’s condition evolves.
The sleeve is attached to the heart using a combination of a suction device, sutures and a gel interface to help with friction between the device and the heart.
“The cardiac field had turned away from idea of developing heart compression instead of blood-pumping VADs due to technological limitations, but now with advancements in soft robotics it’s time to turn back,” said Frank Pigula, who works as a cardiothoracic surgeon.
“Most people with heart failure do 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.”
More research needs to be done before the sleeve can be implanted in humans but the research is an important first step towards an implantable soft robot that can augment organ function.
“This research is really significant at the moment because more and more people are surviving heart attacks and ending up with heart failure,” said Roche. “Soft robotic devices are ideally suited to interact with soft tissue and give assistance that can help with augmentation of function, and potentially even healing and recovery.”
Last year, another Harvard team developed 3D-printed organs that could one day replace failing ones in humans.