Medical devices for treating a target site and associated method
Embodiments of the present invention provide devices and methods for treating various target sites, such as vascular abnormalities. For example, a medical device according to one embodiment includes at least one layer of a fabric of braided strands having proximal and distal ends and a central axis extending therebetween. The medical device has an expanded configuration a generally frustroconical shaped portion at each end. The medical device is configured to be constrained to a reduced configuration for delivery through a diagnostic catheter and to at least partially return, when unconstrained, towards the expanded configuration.
1 . A medical device comprising:
two layers of a fabric of braided strands, the medical device having proximal and distal ends and a central axis extending therebetween and having an expanded preset configuration comprising a generally frustoconical shaped portion at each end, wherein, in the expanded preset configuration, each frustoconical shaped portion comprises first and second ends and a conical portion disposed therebetween, wherein the first ends are generally planar and face one another and have a larger cross-sectional diameter than the second ends, wherein each frustoconical shaped portion includes a cylindrical portion between the first end and the conical portion, wherein the second ends correspond to the proximal and distal ends of the medical device, wherein the ends of the braided strands are secured from unraveling at the proximal and distal ends of the medical device, wherein the medical device is biased towards the expanded preset configuration such that the medical device is configured to self-expand and at least partially return, when unconstrained, towards the expanded preset configuration,
and wherein the frustoconical shaped portions are shaped to reduce an outer profile of the medical device in an elongated, reduced configuration and to reduce (i) an applied axial force required to constrain the medical device in the reduced configuration within a 4 French (Fr) or 5 Fr 0.038-inch guidewire compatible diagnostic catheter for delivery to a target site and (ii) the applied axial force required to deploy the medical device from the diagnostic catheter at the target site, and
wherein the medical device further comprises a central portion coupling the first ends of the frustoconical shaped portions, and wherein, in the expanded preset configuration, the central portion has a diameter of between 0.5 mm and 1.5 mm, and the cylindrical portions each have a diameter of between 3 mm and 14 mm.
2 . The medical device of claim 1 , wherein the fabric of braided strands comprises a shape memory material.
3 . The medical device of claim 1 , wherein the central portion has a cross-sectional dimension substantially less than that of the first ends of the frustoconical shaped portions.
4 . The medical device of claim 1 , wherein each frustoconical shaped portion has approximately the same maximum outer diameter when the medical device is in the expanded preset configuration.
5 . The medical device of claim 1 , wherein the frustoconical shaped portions are spaced axially apart from one another along the central axis so as to define a gap therebetween, the medical device further comprising a central portion coupling the first ends and extending within the gap.
6 . The medical device of claim 1 , wherein each conical portion is spaced axially from the first end towards the second end along the central axis.
7 . The medical device of claim 1 , wherein the two layers of the fabric of braided strands each comprise a respective tubular member.
8 . The medical device of claim 1 , wherein the two layers of the fabric of braided strands are configured to at least partially inhibit the flow of blood between the proximal and distal ends so as to occlude a target site in which the medical device is delivered.
9 . The medical device of claim 1 , wherein a length of the central portion is significantly less than a length of either generally frustoconical shaped portion in the expanded preset configuration.
10 . The medical device of claim 9 , wherein the length of the central portion is 0.015 inches-0.025 inches in the expanded preset configuration.
11 . The medical device of claim 1 , wherein a length of the medical device between the proximal and distal ends of the medical device in the expanded preset configuration is less than 25 mm.
12 . The medical device of claim 1 , wherein the medical device further comprises a pair of end clamps securing respective ends of the braided strands at the proximal and distal ends of the device, and wherein an outer diameter of one of the end clamps is a maximum outer diameter of the medical device in the reduced configuration.
13 . The medical device of claim 1 , wherein the medical device further comprises a pair of end clamps securing respective ends of the braided strands at the proximal and distal ends of the device, and wherein a maximum diameter of each frustoconical shaped portion when the medical device is in the expanded preset configuration is at least three times an outer diameter of either of the end clamps.
14 . A delivery system comprising:
a 4 Fr or 5 Fr 0.038-inch guidewire compatible diagnostic catheter;
a delivery device having a distal end configured to be inserted within an inner lumen of the diagnostic catheter; and
the medical device of claim 1 coupled to a proximal end of the delivery device.
15 . A method of treating a target site within a body, the method comprising:
performing a diagnostic procedure implemented using a diagnostic catheter, wherein the diagnostic catheter is a 4 Fr or 5 Fr 0.038-inch guidewire compatible diagnostic catheter;
providing a medical device including two layers of a fabric of braided strands, the medical device having proximal and distal ends and a central axis extending therebetween and having an expanded preset configuration comprising a generally frustoconical shaped portion at each end, wherein, in the expanded preset configuration, each frustoconical shaped portion comprises first and second ends and a conical portion disposed therebetween, wherein the first ends are generally planar and face one another and have a larger cross-sectional diameter than the second ends, wherein each frustoconical shaped portion includes a cylindrical portion between the first end and the conical portion, wherein the second ends correspond to the proximal and distal ends of the medical device, wherein the ends of the braided strands are secured from unraveling at the proximal and distal ends of the medical device, wherein the medical device is biased towards the expanded preset configuration such that the medical device is configured to self-expand and at least partially return, when unconstrained, towards the expanded preset configuration;
constraining the medical device from the expanded preset configuration to a reduced configuration for delivery through the same diagnostic catheter with which the diagnostic procedure was implemented, by applying a reduced axial force associated with the generally frustoconical shaped portions at each end of the medical device;
delivering the medical device through the diagnostic catheter proximate to the target site without withdrawing the diagnostic catheter after the diagnostic procedure; and
deploying the medical device from the diagnostic catheter such that the medical device at least partially returns towards the expanded preset configuration, by applying the reduced axial force associated with the generally frustoconical shaped portions at each end of the medical device,
wherein the medical device further comprises a central portion coupling the first ends of the frustoconical shaped portions, and wherein, in the expanded preset configuration, the central portion has a diameter of between 0.5 mm and 1.5 mm, and the cylindrical portions each have a diameter of between 3 mm and 14 mm.
16 . The method of claim 15 , wherein the constraining the medical device to the reduced configuration includes axially elongating the medical device.
17 . The method of claim 15 , further comprising attaching one end of the medical device to a delivery device and advancing the medical device into the diagnostic catheter while attached to the delivery device.
18 . The method of claim 15 , wherein the constraining the medical device to the reduced configuration comprises applying the axial force to the medical device, wherein the applied axial force is 1.5 pounds (lb) or less.
19 . The method of claim 15 , wherein performing a diagnostic procedure comprises delivering contrast media to the target site through the diagnostic catheter.