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Highly performing small diameter polyurethane vascular grafts

Objective

There is an urgent need to design and fabricate reliable small-diameter vessel grafts (SDVC) which could be taken from the shelf and used with a good degree of acceptability in any low diameter vessel replacement. This is related to the scarce availability of autologous prostheses (saphenous vein and mammary artery), the generally unsatisfactory condition of such material, and to the absence on the market of reliable small-diameter synthetics. The principal use of these grafts is in the peripheral districts e.g.: below the knee, and at the cardiac level, e.g.: coronary artery bypass.
The overall objective of the HYPER-GRAFT project is to produce less than 6 mm internal diameter artificial vessels to replace autologous blood vessels in humans. The specific project objectives are to prove with animal implantation experiments that these artificial prototypes are at least comparable with autologous vessels.

The main thrust of the HYPER-GRAFT project is to investigate fundamental issues related to the design and fabrication of a new generation of highly performing polyurethane SDVG capable of elastically withstanding blood pressure, to be selfsealing, to remain patent in a low flow configuration, and not to induce neointimal hyperplasia in the anastomotic regions. The grafts must promote a minimal tissue connective growth on the luminal surface and support the formation of a thin and stable "neointima", and last but not least to be "biostable" in long term implantation situations.

The HYPER-GRAFT project is based upon a number of key features. First, a new innovative technology, patented by Kontron Instruments (KONTRON Milano, Italy) and further developed by the Istituto di Fisiologia Clinica CNR (IFC-CNR Pisa, Italy), will be adapted to the fabrication of small-diameter vessel grafts. Secondly, novel biostable polyurethanes, developed by the Cooperative Research Center for Cardiac Technology (CRC-CT Sydney, Australia), will be used in the process. Thirdly, state of the art pre-clinical techniques will be used by the Cardio Vascular Surgery Service of Hospital Broussais (BROUSSAIS Paris, France), CRC-CNR and the University of Liverpool (LIVERPOOL United Kingdom) to evaluate the prostheses and to feed back to the design and the manufacturing process.

A distinctive feature of the HYPER-GRAFT project is that it will contribute substantially to the understanding of the relation between graft microporous structure and dynamic mechanical properties, the interaction mechanisms between graft microporous structure, both of the luminal surface and of the wall, and early thrombosis, tissue ingrowth and endothelialization, and the complicated phenomenon involved in graft biodegradation. It is considered that this fundamental knowledge, which is not widely addressed in current vascular graft research, will have a profound impact not only on the specific class of devices being investigated as demonstrators within the project, but also on the whole area of implantable materials and the broad field of biomedicine.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

NATIONAL RESEARCH COUNCIL OF ITALY
Address
41,Via Trieste 41
56126 Pisa
Italy

Participants (3)

Cooperative Research Centre for Cardiac Technology
Australia
Address

2065 Royal St. Leonards - Sidney - Nsw
THE UNIVERSITY OF LIVERPOOL
United Kingdom
Address
Daulby Street Royal Liverpool University Hospital
L69 3GA Liverpool
Université Pierre et Marie Curie - Paris VI
France
Address
96,Rue Didot
75014 Paris