Review Tissue engineering of vascular conduits K.-H. Yow 1,2 , J. Ingram 1 , S. A. Korossis 1 , E. Ingham 1 and S. Homer-Vanniasinkam 2 1 Institute of Medical and Biological Engineering, University of Leeds and 2 Vascular Surgical Unit, Leeds General Infirmary, Leeds, UK Correspondence to: Mr K.-H. Yow, Vascular Surgery, Good Hope Hospital NHS Trust, Sutton Coldfield, Birmingham B75 7RR, UK (e-mail: heng yow@yahoo.co.uk) Background: Autologous conduits are not available in up to 40 per cent of patients with arteriopathy who require coronary or lower limb revascularization, and access sites for renal dialysis may eventually become exhausted. Synthetic prostheses achieve a poor patency rate in small-calibre anastomoses. This review examines how vascular tissue engineering may be used to address these issues. Methods: A Medline search was performed, using the keywords ‘vascular tissue engineering’, ‘small diameter vascular conduit’, ‘vascular cell biology’, ‘biomechanics’, ‘cell seeding’ and ‘graft endothelialization’. Key references were hand-searched for relevant papers. Results and conclusion: In vitro and in vivo approaches are currently being used for guided cell repopulation of both biological and synthetic scaffolds. The major clinical problem has been extended culture time (approximately 6 weeks), which precludes their use in the acute setting. However, recent advances have led not only to improved patency rates for prostheses, but also to a potential reduction in culture time. In addition, increased mobilization of endothelial progenitor cells in the presence of ischaemic tissue may increase the autologous cell yield for scaffold reseeding with further reduction in culture time. Paper accepted 17 January 2006 Published online in Wiley InterScience (www.bjs.co.uk). DOI: 10.1002/bjs.5343 Introduction Vascular tissue engineering has been described as ‘an interdisciplinary field that applies the principles and methods of engineering and the life sciences towards the development of biological substitutes that restore, maintain and improve tissue function’ 1 . It aims to develop biocompatible scaffolds that mimic the mechanical properties of autogenous conduits, while providing a framework for guided cell repopulation to enable integration as a functional cardiovascular conduit. Its recent advances developed from an appreciation of the need for viable alternatives to autologous cardiovascular conduits. Despite recent advances in secondary prevention and interventional cardiology 2–4 , coronary artery bypass remains an important therapeutic option, and the incidence of peripheral arterial disease and end-stage renal failure requiring vascular access is increasing 5,6 . Autologous vein is not available in 10–40 per cent of patients as a result of trauma, disease such as varicose veins, or previous surgery 7 . The problem is further compounded by the chronicity of these disease states, resulting in a cohort of patients who will inevitably require reoperation. Synthetic alternatives to vein have poor intermediate and long- term patency rates in vessels with a calibre of less than 6 mm 8 . This review describes the various approaches in vascular tissue engineering, the different scaffolds available, the mechanisms of graft failure and the ongoing matters of graft design, with particular attention to small-calibre grafts. It focuses on the integration of vascular cell biology into graft design, including graft endothelialization and endothelial progenitor cell research. Methods An OVID Medline search was performed under the head- ings ‘vascular tissue engineering’, ‘small calibre/diameter vascular substitute’, ‘vascular cell biology’, ‘biome- chanics’, ‘graft endothelialization’ and ‘cell seeding’ from the years 1966 to 2005. Bibliographies of land- mark papers were hand-searched for further relevant articles. Copyright  2006 British Journal of Surgery Society Ltd British Journal of Surgery 2006; 93: 652–661 Published by John Wiley & Sons Ltd Downloaded from https://academic.oup.com/bjs/article/93/6/652/6142381 by guest on 19 June 2022