Device for Mechanically Induced Ventricular Growth in Single Ventricle Patients

Amy Kyungwon Han, PhD, Assistant Professor in Mechanical Engineering at Seoul National University

Abstract: Current surgical palliation for single ventricle physiology involves bypassing the hypoplastic ventricle to convert the circulation into a one-pump system. Within this paradigm, most current research in myocardial biology and surgical methods is directed towards maintaining the health and function of the systemic single ventricle for as long as possible, and less attention has been paid to strategies for restoring biventricular or one-and-a-half ventricle circulation towards a true functional cure. We present a device that would induce favorable growth by exerting mechanical stimuli on the myocardial tissue of the hypoplastic ventricle to restore size and function. It is well known that mechanical forces contribute to tissue growth and remodeling in the cardiovascular system. This device-based intervention aims to promote eccentric growth to enable increased volume capacity of neonates with hypoplastic ventricles.

An in vitro study on a novel dynamic systemic-pulmonary shunt regulator 

Milad Samaee, PhD, Research Engineer at the Cardiovascular Fluid Mechanics Laboratory at Georgia Tech

Abstract: The modified Blalock–Thomas–Taussig shunt (BTTS) is an aortic to pulmonary shunt, which is implanted as part of a palliative procedure for neonates with congenital heart disease to supply blood flow to the pulmonary arteries. However, a proper balance between the pulmonary and systemic flow ratio (QP:QS) has always been challenging in BTTS patients. The main goal of this study is to develop a novel device to dynamically control shunt flow by expanding a soft balloon around the shunt to restrict excessive flow to the pulmonary artery in a dynamic and programmable manner. The device will control diastolic run-off by closing the shunt during diastole. As proof of concept, the device prototype is tested on a shunt in an in vitro circulation simulator setup. The controllable linear actuator pressurizes the balloon hence the amount of fluid in the balloon dictates a certain level of resistance to the shunt. Instantaneous aortic pressure is recorded as a function of balloon resistance. Dynamic aortic flow, coronary flow, and shunt flow are measured. Results show that pinching the shunt by the device during diastole leads to drastically drop in shunt flow. As a consequence, the aortic pressure increases during diastole. Increase in aortic pressure during diastole results in having higher mean coronary perfusion up to 7%. Data shows a significant improvement in coronary perfusion by using the device. The future goal is developing a device as a sub-cutaneous implant that is wirelessly chargeable and programmable for better clinical management of patients with BTTS.

Design and development of device-based cardiac interventions

Ellen Roche, PhD, Associate Professor at the Institute for Medical Engineering and Science and the Department of Mechanical Engineering at the Massachusetts Institute of Technology

Abstract: My research is focused on device-enabled approaches to assist or augment the heart. Broadly, my group works on technologies to improve structural repair, provide active assistance and deliver biological therapy effectively. This seminar will focus on representative implantable devices that we have worked on in each of these three areas, each addressing an identified shortcoming of existing technologies. In terms of structural repair devices, I will discuss a minimally invasive delivery system for atraumatic repair of intracardiac defects and pediatric cardiac assist devices. Further, I will discuss the use of cyclically active implants to modulate immune response for use as vehicles for cell delivery and a targeted, refillable bioimplant which enables repeated local administration of biological or pharmacological delivery. Finally, I will discuss high fidelity organosynthetic testbeds and computational models designed to validate and interrogate device performance before advancing to in vivo studies.