Stent and method of making same
A stent for vascular interventions having a hybrid open cell geometry. Variants of the stent include bare metal stents and drug-eluting stents. Embodiments of the stent include end projections for radiopaque markers or a discontinuous partial radiopaque coating on low-stress or low-strain regions of the peripheral stent. The stents of the invention are characterized by having thin walls, nested rows of struts, high expansion ratio, high and uniform radial force over entire diametric size and length of device, crush resistance up to and including about 90% of its fully expanded diameter, high fatigue resistance and high corrosion resistance.
1. A stent having an outer abluminal surface and an inner luminal surface, comprising:
a. A plurality of generally sinusoidal circumferential ring members having peaks and valleys;
b. A plurality of bridge members interconnecting adjacent pairs of sinusoidal circumferential ring members;
c. A plurality of projection members extending from at least one of a proximal and a distal generally sinusoidal circumferential ring member at proximal and/or distal ends of the stent, the projection members further comprising open frame members capable of being engaged with radiopaque cuff members thereupon;
d. A plurality of volume-enhancing features formed in or on the outer abluminal surface of the stent and the plurality of projection members, wherein the plurality of volume-enhancing features further comprise elongate grooves have a depth between about 0.5 μm and about 10 μm; and
e. A drug eluting layer covering the entire outer abluminal surface of the stent and at least substantially or totally filling the plurality of volume-enhancing features, wherein the drug eluting layer substantially fills the plurality of grooves and has a thickness of between about 3 μm to about 20 μm from the outer abluminal surface of the stent.
2. The stent of claim 1 , wherein each of the plurality of sinusoidal circumferential ring members is configured to nest with adjacent sinusoidal circumferential ring members when the stent is in a diametrically unexpanded state.
3. The stent of claim 1 , wherein the plurality of sinusoidal circumferential ring members further has a substantially zig-zag configuration.
4. The stent of claim 3 , further comprising an offset section intermediate circumferentially adjacent peaks and valleys of each circumferential ring member.
5. The stent of claim 1 , wherein the plurality of generally sinusoidal circumferential ring members and the plurality of bridge members have a wall thickness between about 50 μm and about 100 μm.
6. The stent of claim 1 , wherein the plurality of volume-enhancing features have a spacing of about 2 μm and about 10 μm between adjacent volume-enhancing features.
7. The stent of claim 1 , wherein each of the plurality of volume-enhancing features have a width between 0.5 and 10 μm.
8. The stent of claim 7 , wherein each of the plurality of volume-enhancing features have a width to depth ration between about 1:1 and 1:3.
9. The stent of claim 1 , wherein the plurality of volume-enhancing features are formed in the plurality of sinusoidal circumferential ring members and in the plurality of bridge members.
10. The stent of claim 1 , wherein each of the open frame members further comprises a substantially quadrilateral frame having a central open region.
11. The stent of claim 10 , further comprising a radiopaque cuff member joined to each of the plurality of projection members such that a portion of the radiopaque cuff member is coplanar with the projection member to which it is joined.
12. The stent of claim 11 , wherein the radiopaque cuff member has a portion thereof recessed within the central open region.
13. The stent of claim 1 , further comprising a radiopaque coating on at least a portion of the outer abluminal surface of the stent.
14. The stent of claim 1 , wherein the plurality of circumferential ring members and the plurality of bridge members further define a plurality of open cells.
15. The stent of claim 14 , wherein the plurality of open cells further comprises at least two different open cell configurations.
16. The stent of claim 15 , where the at least two different open cell configurations further comprise a first open cell configuration positioned at or proximate to opposing ends of the stent and a second open cell configuration positioned along an intermediate portion of the stent.
17. The stent of claim 16 , wherein the first open cell configuration further comprises a generally V-shaped open cell configuration.
18. The stent of claim 17 , wherein the second open cell configuration further comprises a generally Z-shaped open cell configuration.
19. The stent of claim 1 , wherein the plurality of elongate grooves are oriented substantially parallel to a longitudinal axis of the stent.