A system for deploying a device to a distal location across a diseased vessel, comprising: an expandable sheath comprising an expandable distal portion and an expandable hoop member coupled to the expandable distal portion, the expandable distal portion comprising a porous wall defining a first lumen therethrough, the distal portion having a collapsed configuration, wherein the sheath has a first cross sectional outer diameter and a first lumen inner diameter, and an expanded configuration, wherein the sheath has a second cross sectional outer diameter and a second lumen inner diameter, wherein the expandable sheath is configured to expand from the collapsed configuration to the expanded configuration; wherein in the collapsed configuration, the sheath is configured to be advanced across at least a portion of the diseased vessel to a position adjacent the distal location without substantial size interference between the first cross sectional outer diameter of the sheath and an inner diameter profile of a lumen of the diseased vessel; wherein said sheath comprises a proximal portion having a stiffer structural modulus than said distal portion, the wall of said sheath containing a second lumen capable of housing a tensile member, wherein the hoop member is configured to hold the distal portion of the sheath in the expanded configuration when tension in the tensile member is released, and wherein application of tension to the tensile member collapses the hoop member and distal portion of the sheath thereby capturing blood clots or plaque pieces in the expandable distal portion of the sheath; wherein upon positioning the collapsed configuration to the desired position relative to the distal location, the sheath may be expanded to the expanded configuration to facilitate passage of one or more relatively large diameter structures through the first lumen that are larger in diameter than the first cross sectional outer diameter, the expanded configuration diverting at least a portion of the flow of blood through the diseased vessel across the porous wall of the sheath; wherein upon completion of passage of the one or more relatively large diameter structures, the sheath may be collapsed back to the collapsed configuration, the system further comprising a removable expansion retention member configured to retain the expandable sheath in the collapsed state, and wherein removal of the removable expansion retention member exposes the sheath; and an obturator assembly comprising an elongate coupling member and an atraumatic obturator tip, positioned through the first lumen, wherein movement of the atraumatic obturator tip allows the hoop member to expand. an expandable sheath comprising an expandable distal portion and an expandable hoop member coupled to the expandable distal portion, the expandable distal portion comprising a porous wall defining a first lumen therethrough, the distal portion having a collapsed configuration, wherein the sheath has a first cross sectional outer diameter and a first lumen inner diameter, and an expanded configuration, wherein the sheath has a second cross sectional outer diameter and a second lumen inner diameter, wherein the expandable sheath is configured to expand from the collapsed configuration to the expanded configuration; wherein in the collapsed configuration, the sheath is configured to be advanced across at least a portion of the diseased vessel to a position adjacent the distal location without substantial size interference between the first cross sectional outer diameter of the sheath and an inner diameter profile of a lumen of the diseased vessel; wherein said sheath comprises a proximal portion having a stiffer structural modulus than said distal portion, the wall of said sheath containing a second lumen capable of housing a tensile member, wherein the hoop member is configured to hold the distal portion of the sheath in the expanded configuration when tension in the tensile member is released, and wherein application of tension to the tensile member collapses the hoop member and distal portion of the sheath thereby capturing blood clots or plaque pieces in the expandable distal portion of the sheath; wherein upon positioning the collapsed configuration to the desired position relative to the distal location, the sheath may be expanded to the expanded configuration to facilitate passage of one or more relatively large diameter structures through the first lumen that are larger in diameter than the first cross sectional outer diameter, the expanded configuration diverting at least a portion of the flow of blood through the diseased vessel across the porous wall of the sheath; wherein upon completion of passage of the one or more relatively large diameter structures, the sheath may be collapsed back to the collapsed configuration, the system further comprising a removable expansion retention member configured to retain the expandable sheath in the collapsed state, and wherein removal of the removable expansion retention member exposes the sheath; and an obturator assembly comprising an elongate coupling member and an atraumatic obturator tip, positioned through the first lumen, wherein movement of the atraumatic obturator tip allows the hoop member to expand.