US Patent 8474120 Bifurcated highly conformable medical device branch access

A method of making a multi-lumen stent graft includes covering a first mandrel that comprises a groove and a back wall of the groove with an innermost polymeric tube; slitting the innermost polymeric tube along the back wall of the groove; placing a second mandrel into the groove of the first mandrel and aligning the second mandrel with the back wall of the groove, deforming the innermost polymeric tube; placing an outermost polymeric tube over the innermost polymeric tube; and cutting an opening in the outermost polymeric tube over the second smaller mandrel, wherein the outermost polymeric tube and innermost polymeric tube comprise a graft member.