Multi-layer braided structures for occluding vascular defects and for occluding fluid flow through portions of the vasculature of the body
A collapsible medical device and associated methods of occluding an abnormal opening in, for example, a body organ, wherein the medical device is shaped from plural layers of a heat-treatable metal fabric. Each of the fabric layers is formed from a plurality of metal strands and the assembly is heat-treated within a mold in order to substantially set a desired shape of the device. By incorporating plural layers in the thus-formed medical device, the ability of the device to rapidly occlude an abnormal opening in a body organ is significantly improved.
1. A medical device comprising:
an outer fabric layer surrounding at least one inner fabric layer, each of the outer and inner fabric layers comprising a plurality of braided metal strands extending from a proximal end to a distal end of each of the outer and inner fabric layers, the outer and inner fabric layers having an expanded preset configuration and configured to be constrained from the expanded preset configuration to a lesser cross-sectional dimension for delivery to a treatment site in a patient's body, the outer and inner fabric layers having a memory property such that the outer and inner fabric layers tend to return to the expanded preset configuration when unconstrained.
2. The medical device of claim 1 , wherein a pitch of the plurality of braided metal strands comprising the outer and inner fabric layers are generally equal.
3. The medical device as in claim 1 , wherein the braided metal strands comprising the outer fabric layer are of a larger diameter than the braided metal strands comprising the at least one inner fabric layer.
4. The medical device as in claim 1 , wherein a number of braided metal strands comprising the at least one inner fabric layer is greater than a number of braided metal strands comprising the outer fabric layer.
5. The medical device as in claim 1 , further comprising a third fabric layer disposed within the at least one inner fabric layer, the third fabric layer comprising a plurality of braided metal strands and an expanded preset configuration corresponding to the expanded preset configuration of the outer and at least one inner fabric layers.
6. The medical device as in claim 5 , wherein the plurality of braided metal strands of the outer, at least one inner, and third fabric layers have proximal and distal ends that are secured to one another.
7. The medical device as in claim 1 , wherein the plurality of braided metal strands of the outer and at least one inner fabric layers have proximal and distal ends.
8. The medical device as in claim 7 , further comprising at least one clamp for securing the proximal or distal ends of the plurality of braided metal strands of the outer and at least one inner fabric layers together.
9. The medical device as in claim 8 , further comprising a pair of clamps for securing the proximal and distal ends of the plurality of braided metal strands of the outer and at least one inner fabric layers together, respectively.
10. The medical device as in claim 7 , further comprising at least one clamp for securing the proximal or distal ends of the plurality of braided metal strands of the outer fabric layer and at least one clamp for securing the proximal or distal ends of the plurality of braided metal strands of the at least one inner fabric layer.
11. The medical device as in claim 10 , further comprising a pair of clamps for securing the proximal and distal ends of the plurality of braided metal strands of the outer fabric layer, respectively, and a pair of clamps for securing the proximal and distal ends of the plurality of braided metal strands of the at least one inner fabric layer, respectively.
12. The medical device as in claim 7 , wherein each of the inner and outer fabric layers comprises a tubular member having proximal and distal ends corresponding to the proximal and distal ends of the plurality of braided metal strands of the outer and at least one inner fabric layers.
13. The medical device of claim 1 , wherein each of the outer and inner fabric layers comprises an expanded preset configuration, and where the expanded preset configuration of the outer fabric layer is of a different geometrical shape than the expanded preset configuration of the at least one inner fabric layer.
14. The medical device of claim 1 , wherein the plurality of braided metal strands of the outer fabric layer and the at least one inner fabric layer collectively define a strand density configured to facilitate thrombus formation to thereby create an occlusion.
15. The medical device as in claim 1 , wherein the plurality of braided metal strands of the outer and inner fabric layers comprise a shape memory material.
16. The medical device as in claim 1 , wherein each of the outer and at least one inner fabric layers comprises a tubular member.
17. The medical device as in claim 16 , wherein the tubular members are disposed concentrically with respect to one another.