Stent with self-deployable portion
The present invention provides methods and devices for placement of a stent in a bifurcation or ostial lesion. The stent comprises a main body and a flaring portion. The main body is designed to expand and support a main vessel while the flaring portion deploys at least partially in response to expansion of the main body and is designed to open into and support a side branch or bifurcation ostium area. The stent may also comprise a therapeutic agent which can be delivered to a blood vessel.
1. A balloon expandable stent comprising:
a main body having a plurality of radially expandable circumferential rings;
a single flaring portion disposed on one side only of the main body and including at least a distal wing and a proximal wing, wherein each wing has a base and sides and is adapted to flare radially into a side branch;
a U-shaped connector disposed between the main body and each wing, wherein the connector includes two legs and a cross-member where the legs are attached within one of the circumferential rings of the main body and the cross-member is attached to the base of one of the wings, the legs of said connector opening circumferentially where attached to the circumferential rings in response to expansion of the circumferential rings of the main body to cause the cross member to deform to cause the wing to flare radially; and
struts extending from each side of the distal wing and the proximal wing to the main body, wherein the struts open with the distal wing and the proximal wing to provide coverage of a side branch ostium when each wing is opened into said ostium.
2. The balloon expandable stent of claim 1 , wherein the flaring portion consists of two wings aligned axially on the main body.
3. The balloon expandable stent of claim 1 , wherein the wings each flare at an angle in the range from 10 to 150 degrees relative to a central axis of the main body of the balloon expandable stent.
4. The balloon expandable stent of claim 1 , wherein the connector transfers displacement and expansion forces from the main body during expansion to the flaring portion.
5. The balloon expandable stent of claim 1 , wherein the wings each comprise a radiopaque marker disposed above the base and between the sides.
6. The balloon expandable stent of claim 1 , further comprising a therapeutic agent disposed over at least a portion of the balloon expandable stent.
7. The balloon expandable stent of claim 6 , further comprising a polymeric layer, wherein the therapeutic agent is sequestered in the polymer layer.
8. The balloon expandable stent as in claim 1 , wherein the wings have different lengths.
9. A method for delivering a balloon expandable stent comprising:
positioning a stent having a main body and a flaring portion including at least one wing on a side of the main body in a vessel at an ostial opening to a vessel side branch, wherein the flaring portion is attached to the main body by a U-shaped connector with two legs and a cross-member which is attached to a base of the at least one wing; and
inflating a balloon within the main body but not within the flaring portion to radially expand the main body so that the legs are circumferentially opened to deform the cross-member to cause the wing to flare into the ostial opening at least partially in response to expansion of the main body, wherein struts on a side of the wing are pulled into the ostium to provide additional coverage into the ostial opening.
10. The method of claim 9 , further comprising providing a therapeutic agent disposed over at least a portion of the balloon expandable stent.
11. The method of claim 10 , further comprising providing a polymeric layer, wherein the therapeutic agent is sequestered in the polymeric layer.