Soft Robotic Sleeve Supports Heart Function

A new study describes a proof-of-concept soft robotic sleeve that augments cardiac function in order to support a failing heart.

Under development at Boston Children’s Hospital (MA, USA) and the Wyss Institute for Biologically Inspired Engineering (Boston, MA, USA), the implantable robotic system involves a septal anchor, a bracing bar and sealing sleeve that pass through the ventricle wall, and a frame embedded with soft actuators mounted around the ventricle. Anchoring of the frame to the interventricular septum is designed to cause approximation of the septum to the free ventricular wall during systole, and assist with recoil in diastole.

Physiological sensing of the native hemodynamics enables rhythmic loading under organ-in-the-loop control of the robotic implants, thus providing fully autonomous augmentation of heart function. The researchers demonstrated the concept on both right and the left ventricles through in vivo studies of a porcine model, with different heart failure models used to show device function across a spectrum of hemodynamic conditions associated with right and left heart failure. The results showed recovery of blood flow and pressure from the baseline heart failure conditions.

In addition, significant reductions in diastolic ventricle pressure were observed, demonstrating improved filling of the ventricles during diastole, enabling sustainable cardiac output. Another benefit is that as the actuator is an external device, blood is squeezed through the heart's own chamber, and thus could theoretically work with minimal use of anticoagulants. The devices are implanted on the beating heart under echocardiography guidance. The researchers are now modifying the robot for human use. The study was published on November 22, 2017, in Science Robotics.

“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,” said senior author Nikolay Vasilyev, MD, of BCH. “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. Specially-designed elastic bands help return the heart's wall to its original position, filling the chamber sufficiently with blood.”

HF in children is much less common than in adults. While heart transplantation offers effective relief from symptoms, far fewer pediatric sized donor hearts are available for transplantation than for adults, limiting its use in children and prolonging the waiting period until transplant can occur. As a result, the median waiting time for a pediatric donor heart in the United States is 119 days. Overall a reported 12-17% of children and 23% of infants die while on the wait list for a heart transplant.

Related Links:
Boston Children’s Hospital
Wyss Institute for Biologically Inspired Engineering