Robotic implants
Soft robotics for heart failure
I assisted the development of a soft robotic sleeve which could mimic the complex muscular contraction of the heart, including its ability to twist and untwist After inducing a simulated heart failure, the device could restore baseline levels of aortic flow to the body The findings of this work were recently published in Science Translational Medicine.
Subsequently, I led the development of a second generation device which was required to improve the diastolic phase of the cardiac cycle when the heart refills with blood The actuators were re designed from the previous implementation in order to provide greater linear contraction Furthermore, the actuators could store elastic energy in contraction for release during diastole in order to recoil the heart ventricles By mechanically coupling the actuators to the heart, and carefully tuning of the actuator response time with the native heart beat an optimal cardiac output could be achieved with improved diastolic function
Soft robotics for heart failure in a single ventricle
Many instances of heart failure occur exclusively on either the right or left ventricle In another project, I developed an implantable soft robotic device that could provide assistance to a single ventricle Rather than wrapping actuators around the heart, this approach exploits the intraventricular septum as a bracing structure whilst the external ventricle is compressed and relaxed using soft actuators I co developed a delivery system and surgical procedure in which a septal anchoring system could be implanted on to the septum for the soft robotic device to be coupled to To date, approximately 25 in vivo porcine studies have been performed in which this bracing structure has been successfully implanted on the beating heart A collapsible anchor is deployed in to the healthy ventricle and sprung open under ultrasound guidance A disc and bracing bar is attached to this anchor, creating a sandwich on the septum The bracing structure exits the ventricle wall and a sealed ring allows translation of ventricle free wall over the bracing bar
Once the septal anchoring system is implanted on either right or left ventricle, a semilunar frame with embedded soft actuators is attached to the bracing bar. These soft actuators can compress and relax the ventricle outer wall. The reaction forces are transmitted to the septum through the anchoring system which effectively causes approximation of the ventricle wall and septum. This process enables blood to be ejected from the ventricle and in to the circulatory system. Furthermore, the use of septal bracing can compensate unnatural billowing of the septum that sometimes occurs in heart failure due to high filling pressures. This concept has been trialed on both ventricles in vivo in which heart failure models were used to impair heart function, to allow validation of the devices. The developed devices demonstrated repeated ability to restore heart function to the failing ventricles in terms of blood flow, systolic and diastolic ventricle pressures.
