Improvements in synthetic vascular grafts

A synthetic vascular graft (10) has a fibrous structure (11) and mechanical properties matching substantially mechanical properties of its natural counterpart, the fibrous structure including coating means of non-biodegradable elastomeric material for protecting fibres of the structure from tissue and capillary ingrowth into the wall of the graft, the coating (12) being of a material and thickness not to alter adversely the mechanical properties of the graft before the coating (12) is present. Alternatively or additionally, individual fibres within the structure are coated.