Session: 07-04-01: Biomaterials and Tissue: Modelling, Fabrication and Characterization

Paper Number: 192194

On the Development of Small-Diameter Vascular Grafts 

There is a high demand for artificial blood vessels suitable for use in small diameter vascular graft (SDVG) applications such as lower limb bypass surgery and coronary bypass surgery. However, there are very few products available which have different types of physiological and mechanical issues often resulting in failure limiting their long-term effectiveness. Graft conduits already exist and are widely used for larger vessels (≥6mm) such as the aorta, remaining viable for ten or more years after implantation. The unique challenges inherent in small diameter vessels have prevented the same technology from scaling down, leading to deterioration and failure within a short time. Among these issues are thrombosis, intimal hyperplasia, and most importantly the mechanical compliance mismatch between the natural vessel and the artificial conduit. This has been widely considered as the primary cause for failure and a trigger to other stated issues. Hence, it is necessary to find a suitable conduit for small diameter grafts, and as such researchers have been approaching the problem from both bioengineering and mechanical engineering viewpoints, with many competing ideas being at various research and development phases. It is vital for a successful vascular graft to closely match the mechanical properties of the natural blood vessel, while biocompatibility of the graft also allows the body to integrate the implanted graft with no rejection. Improvements have been made according to the latest literature in diminishing some of the common issues. However, the compliance issue still persists. The authors have previously devised some innovative design modifications and proposed configurations to enhance deformation, vibration and stress distribution for metallic as well as piezoelectric circular cylindrical hollow geometries with applications in biomedical and other industrial sectors. This approach employs a stepped thickness configuration with alternate thin and thick portions which localises deformation within predetermined regions and provides a controlled dynamic behaviour. It has been shown that a carefully designed stepped thickness configuration can yield anticipated dynamic behaviour and the authors contemplate such approach has the potential and seems to be a promising solution to the compliance mismatch issue for such tubular biocompatible grafts and conduits.

Hence, the aim of this work is to review the current state-of-the-art in this field and identify and propose the promising future research avenues for further investigation to meet the needs of an artificial SDVG conduit. Mechanical compliance is a key focus of this work and some preliminary experimental observations, design solutions and approaches to resolve and enhance this compliance mismatch issue are discussed and presented.

Presenting Author: Ahmed M Al-Jumaily Auckland University of Technology

Presenting Author Biography: Ahmed M. Al-Jumaily, is currently a Professor of Biomechanical Engineering at the Institute of Biomedical Technologies at the Auckland University of Technology, Auckland, New Zealand. He holds a PhD and M.Sc. from the Ohio State University, USA and a B.Sc. from the University of Baghdad. He is a FELLOW member of the American Society of Mechanical Engineering (ASME) and the Acoustical Society of America (ASA), and a member of 10 more international professional societies. He is the Editor- in- Chief Founder of the ASME Journal of Medical Diagnostics and Therapy and of the ASME monograph series-Biomedical and Nanomedical Technologies and has been on the editorial and refereeing boards for several international journals. He has published more than 400 papers in international journals and conference proceedings including four ASME books on Vibration and Acoustics in Biomedical Applications and CPAP devices. He has supervised more than 130 postgraduate students from 35 countries in biomedical applications, vibrations, biomechanics, and electroactive polymers. During his academic career he has forged strong alliances between academia and industries in the medical devices area, which has resulted in many successful grants and contracts with companies and research organizations. Al-Jumaily’s current research focuses on biomedical applications with particular interest in the application of vibration and acoustics to airways constriction therapies, low frequency ultrasound skin cancer therapy and artery non-invasive diagnostics.

Authors:

Ata Meshkinzar Auckland University of Technology
Kieran Zane Scott Auckland University of Technology
Samuel Joseph Montague Biddick Auckland University of Technology
Ahmed M Al-Jumaily Auckland University of Technology