Core assembly for medical device delivery systems

1. An interventional element delivery system, comprising:

a core assembly sized for insertion into a corporeal lumen, the core assembly comprising—

an elongate member having a distal segment; and

a proximal restraint coupled to or extending over the distal segment of the elongate member, the proximal restraint including—

a bumper section;

an elongate distal section distal to the bumper section;

a lumen extending through the bumper and distal sections; and

an undercut section at least partially surrounding the lumen;

an interventional element having a proximal end portion and a distal end portion opposite the proximal end portion along a longitudinal dimension of the interventional element, the interventional element extending along the distal segment of the elongate member such that the undercut section of the proximal restraint receives the proximal end portion of the interventional element and limits proximal translation of the proximal end portion of the interventional element and the distal end portion of the interventional element is positioned distal to the proximal restraint; and

a tubular member configured to be positioned over the core assembly and the interventional element such that, when the interventional element is positioned within the tubular member, the interventional element assumes a compressed configuration, and wherein the tubular member is configured to be proximally retracted relative to the interventional element and the core assembly such that the interventional element radially expands from its distal end portion to its proximal end portion.

2. The system of claim 1 , wherein the undercut section comprises a recess formed in the bumper section.

3. The system of claim 1 , wherein the undercut section is radially peripheral to the distal section.

4. The system of claim 1 , wherein the bumper section comprises a distal end portion including a surface defining a plane, and wherein a portion of the undercut section is proximal to the plane.

5. The system of claim 4 , wherein a proximalmost point of the undercut section is separated from the plane by at least about 0.05 millimeters.

6. The system of claim 4 , wherein a proximalmost point of the undercut section is separated from the plane by no more than 0.1 millimeters.

7. The system of claim 1 , wherein the bumper section includes a first radial outer surface and the distal section includes a second radial outer surface, and wherein the undercut section is positioned between the first radial outer surface and the second radial outer surface.

8. The system of claim 1 , wherein the undercut section comprises a recess formed in the distal section.

9. The system of claim 8 , wherein the undercut section abuts the bumper section.

10. The system of claim 8 , wherein the distal section includes an outer surface defining a cylindrical surface extending longitudinally around the lumen, wherein an innermost portion of the undercut section is inward of the cylindrical surface.

11. The system of claim 10 , wherein the innermost portion of the undercut section is separated from the cylindrical surface by at least about 0.05 millimeters.

12. The system of claim 1 , wherein the interventional element comprises a mesh or plurality of braided filaments.

13. The system of claim 1 , wherein the distal segment of the elongate member extends through the lumen.

14. The system of claim 1 , wherein the core assembly is configured to engage the interventional element such that the interventional element can be resheathed into the tubular member after the interventional element has partially radially expanded.

15. The system of claim 14 , wherein the core assembly comprises an engagement member positioned distal of the proximal restraint, the engagement member having one or more projections configured to engage the interventional element.