Systems and methods to position a prosthesis

A delivery system comprising:

• a primary sheath extending from a primary sheath distal end to a primary sheath proximal end and comprising a primary sheath lumen from the primary sheath distal end to the primary sheath proximal end;
• a secondary sheath extending from a secondary sheath distal end to a secondary sheath proximal end and comprising a secondary sheath lumen from the secondary sheath distal end to the secondary sheath proximal end, the primary sheath at least partially received within the secondary sheath lumen such that the primary sheath translates longitudinally within the secondary sheath lumen, wherein the delivery system has a loaded configuration in which a prosthesis having proximal and distal ends is received within the primary sheath lumen adjacent to the primary sheath distal end in a contracted delivery state;
• a length reference section disposed at the secondary sheath proximal end, wherein the length reference section indicates a preselected length of the primary sheath distal end that extends distally out of the secondary sheath distal end during the contracted delivery state of the prosthesis;
• and
• a sheath-locking section that selectively locks the primary sheath to the secondary sheath such that longitudinal proximal translation of the primary sheath causes longitudinal proximal translation of the secondary sheath.

A method to deploy a prosthesis, the method comprising:

• providing a primary sheath, a secondary sheath, and a prosthesis, where the primary sheath extends from a primary sheath distal end to a primary sheath proximal end and comprises a primary sheath lumen from the primary sheath distal end to the primary sheath proximal end, where the secondary sheath extends from a secondary sheath distal end to a secondary sheath proximal end and comprises a secondary sheath lumen from the secondary sheath distal end to the secondary sheath proximal end, and where the prosthesis has proximal and distal ends and is received within the primary sheath lumen adjacent to the primary sheath distal end in a contracted delivery state;
• disposing the distal end of the secondary sheath adjacent to a proximal end of a receiving lumen of a vessel;
• disposing the primary sheath within the secondary sheath lumen such that a length reference section disposed at the secondary sheath proximal end indicates a preselected length of the primary sheath distal end that extends distally out of the secondary sheath distal end during the contracted delivery state of the prosthesis, the preselected length corresponding to a preselected overlap with the vessel;
• and
• longitudinally translating the primary sheath and the secondary sheath proximally relative to the prosthesis, wherein the longitudinally translating of the primary sheath and the secondary sheath proximally relative to the prosthesis transitions the prosthesis from the contracted delivery state to an expanded deployed state in which the prosthesis is received within the vessel and has the preselected overlap with the vessel.