Medical device delivery systems

1. A medical endoprosthesis delivery system, comprising: an inner member having an outwardly extending portion, wherein the inner member is a single body; an outer member at least partially surrounding the inner member, the inner and the outer members being configured so that an implantable medical endoprosthesis can be disposed between the inner and outer members; an implantable medical endoprosthesis disposed between the inner member and the outer member; wherein the outwardly extending portion includes a proximal end that is disposed proximal of a proximal end of the implantable medical endoprosthesis; wherein the outwardly extending portion includes a distal end that is disposed proximal of a distal end of the inner member, and wherein the distal end of the outwardly extending portion interdigitates with an opening in the implantable medical endoprosthesis; wherein the outwardly extending portion includes an angled region that is disposed over the implantable medical endoprosthesis and that is positioned between the proximal end and the distal end of the outwardly extending portion; wherein the angled portion forms an angle that remains substantially constant during deployment of the implantable medical endoprosthesis; and wherein the outward extending portion is configured to pivot relative to the inner member during deployment of the medical endoprosthesis between a first configuration where the distal end of the outwardly extending portion contacts the inner member and a second configuration; wherein the outwardly extending portion is biased to pivot the distal end of the outwardly extending portion radially inward toward the first configuration.

2. The medical endoprosthesis delivery system of claim 1 , wherein the outwardly extending portion of the inner member is configured so that, when the implantable medical endoprosthesis is disposed between the inner and outer members, the outwardly extending portion of the inner member substantially prevents the implantable medical endoprosthesis from moving distally with respect to the inner member.

3. The medical endoprosthesis delivery system of claim 1 , wherein the outwardly extending portion of the inner member is configured so that, when the implantable medical endoprosthesis is disposed between the inner and outer members and the outer member is moved proximally over a distal portion of the implantable medical endoprosthesis, the outwardly extending portion of the inner member substantially prevents the implantable medical endoprosthesis from moving distally with respect to the inner member.

4. A method of treating a lumen within a subject, the method comprising:

at least partially inserting the system of claim 1 into the lumen.

5. The method of claim 4 , further comprising moving the outer member proximally.

6. A medical endoprosthesis delivery system, comprising:

an inner member, the inner member having an outer surface with a maximum outer diameter;

an outer member at least partially surrounding the inner member;

an implantable medical endoprosthesis disposed between the inner and outer members;

a retainer attached to the inner member and being configured to pivot relative to the inner member, wherein the retainer is configured so that when the implantable medical endoprosthesis is disposed between the inner and outer members, the retainer includes an angled portion that is at least partially disposed over the implantable medical endoprosthesis and a distal end that interdigitates with an opening of the implantable medical endoprosthesis;

wherein the retainer includes a distal portion and a proximal portion and wherein the length of the distal portion is approximately equal to the length of the proximal portion;

wherein the angled portion of the retainer is oriented at a constant angle during deployment of the implantable medical endoprosthesis;

wherein the implantable medical endoprosthesis is configured to shift between an expanded configuration and a collapsed configuration; and

wherein when the implantable medical endoprosthesis is in the collapsed configuration, the implantable medical endoprosthesis has a maximum outer diameter that is greater than the maximum outer diameter of the inner member;

wherein the retainer is biased to pivot the distal end of the retainer radially inward toward the inner member between a first configuration where the distal end contacts the inner member and a second configuration.

7. The medical endoprosthesis delivery system of claim 6 , wherein the inner member is a single body.

8. A medical endoprosthesis delivery system, comprising:

an inner member;

an outer member at least partially surrounding the inner member;

an implantable medical endoprosthesis disposed between the inner and outer members;

a pivoting retainer attached to the inner member, wherein the retainer is configured so that when the implantable medical endoprosthesis is disposed between the inner and outer members, the retainer can be at least partially disposed over the implantable medical endoprosthesis and can interdigitate with an opening of the implantable medical endoprosthesis;

wherein a distal end of the pivoting retainer is disposed proximal of a distal end of the inner member; and

wherein the pivoting retainer is biased to pivot the distal end of the pivoting retainer radially inward toward the inner member between a first configuration where the distal end contacts the inner member and a second configuration.

9. The medical endoprosthesis delivery system of claim 8 , wherein the inner member is a single body.

10. The medical endoprosthesis delivery system of claim 1 , wherein the outwardly extending portion is formed integrally with the inner member.

11. The medical endoprosthesis delivery system of claim 6 , wherein the retainer is formed integrally with the inner member.