The present invention provides an implantable graft, including a primary tubular
body having a first outer wall surface and a first inner wall surface defining
a primary blood contacting lumen, and a secondary tubular body having a second
outer wall surface and a second inner wall surface. The secondary tubular body
is located about the primary tubular body to form a space therebetween. The primary
and secondary tubular bodies are joined by at least one rib.
