Title: Developing a fully implantable, miniaturised ventricular assist device (VAD) for end-stage heart failure patients with facility for trans-cutaneous energy transfer (TET).
Funder: Department of Health (England)

Abstract: The year-wise breakdown of the project plan is described below. The development of the pump and transcutaneous energy transfer mechanism will occur concurrently from the start of the project. Please also refer to the Gantt chart attached to this application. Quarters 1-6: Modelling fluid dynamics with structuring the VAD pump AND Developing miniaturised Transcutaneous Energy Transfer (TET) technique During the first year we will build at least 3 different implantable, experimental prototypes of the VAD pump to demonstrate the concept and optimize the design. Compared with current models, we will make the VAD the lightest (in terms of gross weight), the most efficient (in terms of energy consumption - aiming for at least 8 hours full capacity work without re-charging) and the most bio- and haemo-compatible (to reduce the risk of thrombo-embolism, bleeding and to ensure longevity once implanted in the human body). This will follow designing of different electrical leads aiming to reduce their dimensions as much as possible. During this year, along with developing the pump head prototype, we will also conduct haemocompatibility and thrombogenicity testing on various materials of high durability to identify the best material to construct the pump head. Concurrently, we will investigate widely and incorporate the most efficient and practical means of trans-cutaneous energy transfer to provide sufficient power for at least 8 hours without re-charging at full capacity. The team at Imperial College has already developed TET technology. Thsi will be miniaturised. We will also test varioius types of batteries and will make it compact, bio-compatible and efficient. We will also develop a mechanism of displaying the power store level of the battery in an external hand-held device by a feedback mechanism. Cambridge Reactor Designs will develop the final casing for the TET circuit plus the battery so that they can be inserted in patients as a single unit. Quarters 7-10: Research and construction of the final prototype: With the information gained through experimentation and modelling in the first 18 months of the product development, we will refine the final version of the totally implantable ventricular assist device with trans-cutaneous energy transfer. We will research materials to be used to ensure lightness and bio-compatibility. The model we will design will consist of a pump effectively causing axial fluid displacement by a rotor that moves by electromagnetism the design of which reduces haemolysis by limiting the blood-impeller contact area. The pump head will have a maximum diameter of 23-25 mm. The maximum length of the pump head will be 50 mm. We will research and select power leads and energy sources using the results from trials conducted in the first 18 months and design the TET interface along with available implantable battery technology. We will manufacture the final prototype and perform trials with blood to measure levels of haemolysis, thrombosis and also to ensure that the required flow rates are achieved. Quarters 11-12: Refining the structural details of the model and testing performance in a commercial ex vivo perfusion model: In the final 6 months, we will design the structural parameters for various sizes of the pumps based on the varying body surface of patients and diameter of the native aortic annulus. The TET technology and the pump head developed will be connected to each other during this phase of the study. We will model the changes in charge consumption and flow characters with different size pump prototypes. This will then be tested in a commercial ex vivo perfusion model.


Research activity codes: 5.3 MEDICAL DEVICES
Health categories: CARDIOVASCULAR