US Patent 8062346 Flexible stent-graft device having patterned polymeric coverings

The present invention provides an endoprosthesis comprising a radially distensible, tubular stent comprising opposed open ends and a stent wall structure having opposed exterior and luminal surfaces; and a continuous and seamless ePTFE tubular covering having a node and fibril structure securably disposed to at least one of the stent surfaces, the graft covering comprising at least two laminated layers, wherein the laminated layers include at least one region where the laminated layers are not securely bonded; and the at least one region has a different bending flexibility from the tubular graft covering.