Embolic coil delivery systems and components with frangible release features

1 . A system for delivering an embolic coil device, comprising:

a flexible elongate delivery shaft having a distal region and defining a delivery shaft lumen;

an embolic coil device detachably connected to said distal region of said elongate delivery shaft, wherein said embolic coil device includes coil windings that define a coil lumen;

an elongate pull wire positioned at least partially within said delivery shaft lumen and at least partially within said coil lumen, wherein said pull wire includes a frangible segment positioned within said coil lumen; and

wherein said frangible segment of said pull wire defines a predictable region of separation of the pull wire in response to tensile force applied to the pull wire so as to detach said embolic coil device from said delivery shaft.

2 . The system for delivering an embolic coil device of claim 1 ,

wherein said pull wire includes a distal segment that is distal of said frangible segment, wherein said distal segment of said pull wire is attached to said embolic coil device at a distal end of said embolic coil device.

3 . The system for delivering an embolic coil device of claim 2 , wherein the distal segment is attached to said embolic coil device by a weld.

4 . The system for delivering an embolic coil device of claim 2 , wherein said distal segment is attached to said embolic coil device at a second location distal of said frangible segment.

5 . The system for delivering an embolic coil device of claim 4 , wherein the distal segment is attached to said embolic coil device at said second location by a weld.

6 . The system for delivering an embolic coil device of claim 2 ,

wherein said frangible segment has a cross-sectional dimension that is smaller than a cross-sectional dimension of a proximal segment of said pull wire immediately proximal of said frangible segment; and

wherein said frangible segment has a cross-sectional dimension that is smaller than a cross-sectional dimension of said distal segment immediately distal of said frangible segment.

7 . The system for delivering an embolic coil device of claim 1 , wherein said pull wire is metallic.

8 . The system for delivering an embolic coil device of claim 1 , wherein said pull wire is attached to said delivery shaft at a pull wire attachment location.

9 . The system for delivering an embolic coil device of claim 8 , wherein said delivery shaft includes a breakable section at which said delivery shaft is configured to selectively break and separate in response to bending forces applied across said pull wire attachment location of said delivery shaft.

10 . The system for delivering an embolic coil device of claim 1 , wherein said coil windings are helical.

11 . An embolic coil device for detachable connection to an elongate delivery shaft of an embolic coil delivery system, comprising:

coil windings, wherein said coil windings define a coil lumen;

a pull wire extending within said coil lumen;

wherein said pull wire includes a frangible segment positioned within said coil lumen; and

wherein said pull wire includes a distal segment that is distal of said frangible segment, wherein said distal segment is attached to said coil windings at a distal coil tip of said coil windings.

12 . The system for delivering an embolic coil device of claim 11 , wherein the distal segment is attached to said distal coil tip of said coil windings by a weld.

13 . The system for delivering an embolic coil device of claim 11 ,

wherein said distal segment is attached to said coil windings at a second location immediately adjacent to said frangible segment.

14 . The embolic coil device of claim 13 , wherein the distal segment is attached to said embolic coil device at said second location by a weld.

15 . The embolic coil device of claim 11 , wherein said coil windings are helical.

16 . The embolic coil device of claim 11 , wherein said pull wire further comprises a proximal segment extending immediately proximally from said frangible segment.

17 . The embolic coil device of claim 16 , wherein said frangible segment has a cross-sectional dimension that is smaller than a cross-sectional dimension of said proximal segment of said pull wire immediately proximal of said frangible segment.

18 . The embolic coil device of claim 16 , wherein said distal segment of said pull wire has a cross-sectional dimension that is equal to the cross-sectional dimension of said proximal segment of said pull wire.

19 . The embolic coil device of claim 11 , wherein said frangible segment has a cross-sectional dimension that is smaller than a cross-sectional dimension of said distal segment of said pull wire immediately distal of said frangible segment.

20 . The embolic coil device of claim 11 , wherein said pull wire is metallic.

21 . A method comprising:

guiding an embolic coil device detachably connected to a delivery shaft by a pull wire to a desired location in a vasculature of a patient, wherein said embolic coil device includes coil windings that define a coil lumen, and wherein the pull wire is positioned at least partially within a delivery shaft lumen defined by said delivery shaft and at least partially within said coil lumen; and

applying a tensile force to said pull wire to break said pull wire at a frangible segment of said pull wire positioned within said coil lumen, so as to detach said embolic coil device from said delivery shaft.

22 . The method of claim 21 , further comprising:

retracting said delivery shaft from the vasculature of the patient.