Method for treating aneurysms

1. A mechanically expandable device for treating a bifurcation or trifurcation aneurysm, the aneurysm having an aneurysm neck, the device comprising:

a generally tubular structure having a proximal end, a distal end, and an exterior surface defined by a plurality of interconnected struts forming a series of peaks and valleys having interstitial spaces therebetween, said generally tubular structure expandable from a first position to a second position, and said tubular structure is configured to expand radially outwardly to the second position such that the exterior surface of said structure engages with the inner surface of a bifurcation or trifurcation branch so as to maintain a fluid pathway through said branch and to constrict the aneurysm neck such that blood circulation to the aneurysm is reduced;

wherein, in the second position, the tubular structure has a cylindrical portion and a tapered portion, the cylindrical portion having a substantially uniform diameter along its longitudinal length, the tapered portion flaring outwardly from the cylindrical portion to the proximal end of the tubular structure, the cylindrical portion comprising a plurality of rings interconnected by a plurality of interconnecting struts, the tapered portion comprising a distalmost ring, a proximalmost ring, and a distal interconnecting strut extending between a peak of the distalmost ring and a valley of the proximalmost ring, the proximalmost ring having a longer longitudinal length than any of the rings in the cylindrical portion, the distal interconnecting strut having a longer longitudinal length than any of the interconnecting struts in the cylindrical portion, and each of the plurality of rings in the cylindrical portion, the distalmost ring, and the proximalmost ring encircling a longitudinal axis of the tubular structure.

2. The device according to claim 1 , wherein the tubular structure comprises a self-expanding structure.

3. The device according to claim 1 , wherein the tubular structure comprises a plastically deformable structure.

4. The device according to claim 1 , wherein the struts comprise at least one material selected from the group consisting of: platinum, iridium, and tungsten.

5. The device according to claim 1 , wherein the struts are constructed and arranged in a pattern to achieve, when expanded, one or more of enhanced strength, increased expansion ratio, increased coverage area, enhanced longitudinal flexibility, and enhanced longitudinal stability.

6. The device according to claim 1 , wherein the device has a longitudinal axis and wherein at least two of the struts comprise a portion configured to transition to a lateral or near lateral orientation relative to the longitudinal axis when the device is expanded.

7. The device according to claim 1 , further comprising at least one marker.

8. The device according to claim 7 , wherein the at least one marker comprises a radiopaque marker.

9. The device according to claim 7 , wherein the at least one marker is positioned at an end portion of the device or a middle portion of the device.

10. The device according to claim 7 , wherein the at least one marker has a disk shape or a star shape.

11. The device according to claim 1 , further comprising a coupling strut extending between a valley of the proximalmost ring and a peak of a ring of the cylindrical portion.

12. The device according to claim 11 , wherein the coupling strut and the distal interconnecting strut extend along a common, substantially linear path along the exterior surface of the tubular structure.

13. The device according to claim 11 , further comprising a proximal interconnecting strut extending between the peak of the cylindrical portion ring and a valley of a second ring of the cylindrical portion, the second ring being proximal to the cylindrical portion ring.

14. The device according to claim 13 , wherein the distal interconnecting strut, the proximal interconnecting strut, and the coupling strut extend along a common, substantially linear path along the exterior surface of the tubular structure.

15. The device according to claim 11 , wherein the coupling strut and the distal interconnecting strut extend along different, substantially linear paths along the exterior surface of the tubular structure.

16. The device according to claim 1 , wherein the distal interconnecting strut longitudinal length is greater than a longitudinal length of the distalmost ring and the longitudinal length of the proximalmost ring.

17. The device according to claim 1 , wherein the distalmost ring has a longer longitudinal length than any of the rings in the cylindrical portion.

18. The device according to claim 1 , further comprising a second distal interconnecting strut extending between a second peak of the distalmost ring and a second valley of the proximalmost ring, the second distal interconnecting strut being circumferentially spaced apart from the distal interconnecting strut.

19. The device according to claim 18 , further comprising first and second coupling struts extending between respective first and second valleys of the proximalmost ring and respective first and second peaks of the cylindrical portion ring.

20. The device according to claim 19 , wherein the distal interconnecting strut and the first coupling strut extend along a first common, substantially linear path along the exterior surface of the tubular structure, and wherein the second distal interconnecting strut and the second coupling strut extend along a second common, substantially linear path along the exterior surface of the tubular structure.