Abstract: A prosthetic aortic conduit for replacing a root portion of an aorta is provided. The conduit comprises a first tubular portion and a second tubular portion which are connected together along a substantially common axis. The second tubular portion does not substantially deform in a longitudinal direction and has resilient means which allow said second portion to be expandable in a lateral direction. This second portion is able to deform laterally to mimic the function of the sinuses of Valsalva. The method of manufacturing such a conduit comprises the steps of: a) providing a first tubular conduit suitable for use in heart surgery and having a longitudinal axis and first resilient means allowing some expansion in the longitudinal direction only; b) securing to one of the ends of this first conduit a second tubular conduit suitable for use in heart surgery, this second conduit having second resilient means which allows some expansion in the lateral direction only.