Braided scaffolds
A braided polymeric scaffold, made at least in part from a bioresorbable material is deployed on a catheter that uses a push-pull mechanism to deploy the scaffold. A drug coating is disposed on the scaffold. A plurality of scaffold segments on a catheter is also disclosed.
1. A self-expanding stent for treating a peripheral vessel, comprising:
a segmented braided scaffold including a plurality of braided scaffold segments configured to be deployed end to end in a vessel, and
at least three of the braided scaffold segments are hybrid segments, each of which comprising non-degradable filaments and degradable filaments woven to form a tubular configuration,
wherein upon deployment of the scaffold from a collapsed state to a deployed state in a body cavity, the degradable filaments degrade and a radial strength or stiffness of the hybrid segments decreases with time,
wherein when the degradable filaments are completely degraded, each hybrid segment comprises a residual stiffness provided by the non-degradable filaments, and
wherein a hybrid proximal end segment a hybrid distal end segment of the scaffold have a higher radial strength or stiffness at deployment than a middle hybrid segment thereof, while having the same residual radial strength or stiffness as the middle hybrid segment, and wherein a first degradable polymer filament of the proximal and distal hybrid end segments has a higher degradation rate than a second degradable polymer filament of the middle hybrid segment so that a rate of decrease to the residual strength or stiffness is faster for the proximal and distal hybrid end segments than the middle hybrid segment.
2. The stent of claim 1 , wherein the non-degradable filaments are nitinol.
3. The stent of claim 1 , wherein the degradable filaments comprise a polymer selected from the group consisting of poly(L-lactide), poly(L-lactide-co-glycolide), poly(DL-lactide), and polyglycolide.
4. The stent of claim 1 , wherein the degradable filaments comprise a bioabsorbable polymer.
5. The stent of claim 1 , wherein the radial strength or stiffness of at least one of the hybrid end segments decreases by no greater than 60% during the first 3 months after deployment.
6. The stent of claim 1 , wherein the radial strength or stiffness of at least one of the proximal and distal hybrid end segments decreases by at least about 50% during the first 3 months after deployment.
7. The stent of claim 1 , wherein the stiffness of at least one of the proximal and distal hybrid end segments decreases to 40 to 60% of a stiffness at deployment during the first 3 months after deployment.
8. The stent of claim 1 , wherein the stiffness of at least one of the proximal and distal hybrid end segments decreases to a residual stiffness that is less by 40% to 60% of a deployed stiffness, by at least 3 months after deployment.
9. The stent of claim 1 , wherein a combined length of the distal and proximal hybrid end segments are 10% to 30% of a total length of the scaffold.
10. The stent of claim 1 , wherein one of the hybrid proximal end segment and hybrid distal end segment comprises a metal filament having a cross sectional area (Am), and a degradable filament having a cross-sectional area (Ap), wherein the ratio Ap/Am is 2 to 4.
11. The stent of claim 1 , wherein one of the hybrid proximal end segment and hybrid distal end segment comprises a number of metal filaments (Nm) and a number of polymer filaments (Np), wherein the ratio Np/Nm is 2 to 10.