WO2019059949A2

WO2019059949A2 - Flexible intra-vascular aneurysm treatment stent

Info

Publication number: WO2019059949A2
Application number: PCT/US2017/053287
Authority: WO
Inventors: Joseph Horton
Original assignee: Joseph Horton
Priority date: 2017-09-25
Filing date: 2017-09-25
Publication date: 2019-03-28
Also published as: WO2019059949A3

Abstract

An intra-vascular aneurysm-treatment stent and a method for redirecting flow within an aneurysm bubble in a blood vessel. A stent coil is insertable into a blood vessel, the coil made of a material sufficiently flexible to move around curves, loops, and corners in the blood vessel. Selected portions of the stent coil, in cross-section, include various facets on outer surfaces and/or inner surfaces thereof. The stent coil is positioned in the blood vessel with selected stent coil portions proximate an opening into either a saccular aneurysm or a fusiform aneurysm. Blood in the lumen of the blood vessel flows past the leading edges and both over the outer surfaces, and under the inner surfaces. A portion of the blood inside the aneurysm becomes entrained with the blood flowing over the outer surfaces.

Description

FLEXIBLE INTRA-VASCULAR ANEURYSM TREATMENT STENT DESCRIPTION OF THE INVENTION

Field of the Invention

The present invention relates to flexible intra-vascular stents and to flow diverters and modifiers, and more particularly to flexible wire intra-vascular stents for treatment of aneurysms in the carotid and vertebral arteries and branch blood vessels extending from the carotid and vertebral arteries into the brain.

Background of the Invention

An aneurysm is a circumscribed dilation of a blood vessel, or cardiac chamber, in direct communication with its respective lumen, usually resulting from an acquired or congenital weakness of the wall of the blood vessel, or chamber. An aneurysm occurs when a part of the artery, other blood vessel, or cardiac chamber, swells, either due to damage to the wall or a weakness in the wall. As blood pressure builds up with each heartbeat, the wall balloons out at its weakest point, forming an aneurysm bubble. The bubble tends to fill with blood, as blood flowing through the lumen is partly diverted through the opening into the aneurysm. As the aneurysm grows, in addition to causing pain and other complications, a risk of rupture of the bubble increases. Rupture of an aneurysm in a carotid or vertebral artery in the neck, or in a branch blood vessel extending from the carotid or vertebral artery into the brain can cause a hemorrhage or stroke, which can be at best severely debilitating, and at worst deadly. For perspective, aneurysmal subarachnoid hemorrhage (SAH) occurs about 30,000 times annually in the United States. Of these, between 1 /3 and 1/2 of those so afflicted will not survive the trip to the hospital.

Figs. 1 and 2 depict various configurations of aneurysms. In each drawing, a generally tubular blood vessel 10 comprises an inner peripheral wall 12, and an outer peripheral wall 14. The inner peripheral wall 12 defines a lumen 16 through which blood 17 flows. A weak point in the wall 12 has an opening, called a neck, 18. A portion of the blood flow 17 is diverted from the lumen 16 through the neck 18 to form and maintain a saccular aneurysm 20. A saccular aneurysm 20 is shown in Fig. 1 . Fig. 2 shows a fusiform aneurysm 20'. If the arterial wall weakness is focal, i.e., it does not extend all the way around the artery, the aneurysm is most likely to be saccular. If the weakness is circumferential, it will more likely be fusiform. In the saccular aneurysm 20, its communication with the lumen 16 is through the aneurysm neck 18. The fusiform aneurysm 20' by definition does not have a neck.

Figs. 3A and 3B depict a conventional attempt to treat aneurysms. Fig. 3A depicts a wire stent 30, installed in a blood vessel 10 with a fusiform aneurysm bubble 20'. Referring to Fig. 3B, a raised strut portion 32 of the wire stent 30 depicted in Fig. 3A is provided against the blood vessel inner peripheral wall 12 immediately upstream of the aneurysm neck 18. It is intended that an increase in velocity of the blood flow 17 over the raised strut portion 32 will create a pressure drop (dP) at a trailing edge thereof to cause blood 17 in the saccular aneurysm bubble 20 to flow back into the lumen 16 of the blood vessel 10.

Fig. 4 explains why this conventional attempt to treat aneurysms is sometimes ineffective, even harmful. At the trailing edge of the raised strut portion 32, as in the case of a trailing edge of an airplane, the flow of fluid (in this case blood 17) flows across the apex of the wing and down past the trailing edge. The configuration and positioning of the strut 32 in Fig. 3B, however, rather than creating a pressure drop (dP), drawing blood 17 out of the saccular aneurysm 20 and into the lumen 16, instead directs more blood flow 17 at the trailing edge into the saccular aneurysm 20, thereby achieving an effect opposite of that which was intended. In fact, it can have the effect of directing high-velocity blood to strike the inflow zone of the aneurysm, a fragile, delicate part.

SUMMARY OF THE INVENTION

The present invention in one preferred embodiment contemplates an intravascular aneurysm-treatment stent including a flexible coil having a mid-longitudinal axis, insertable into a blood vessel, with selected portions of the coil positioned proximate an opening in a wall of the blood vessel, and opening into an aneurysm bubble, the coil having an upstream proximal end, an opposite downstream distal end, and a length between the proximal end and the distal end, cross sections of the selected portions in a plane parallel to the mid-longitudinal axis of the coil each having a leading edge directed toward the proximal end, a trailing edge directed toward the distal end, and an outer surface and an inner substantially planar surface extending from proximate the leading edges to proximate the trailing edges, the outer surfaces each including at least two flattened surface portions in the cross sections, a first one of the at least two flattened surface portions extending from the trailing edge at least partially toward the proximal end and being angled from, for example, 5° to 80° with respect to the corresponding inner substantially planar surface, and a second one of the at least two flattened surface portions extending from the leading edge at least partially toward the distal end and being angled from, for example, 5° to 80° with respect to the corresponding inner substantially planar surface, a substantially flat first facet being formed on a first portion of the selected portions of the flexible coil adjacent the first one of the at least two flattened surface portions, and a substantially flat second facet being formed on the first portion of the selected portions of the flexible coil adjacent the second one of the at least two flattened surface portions, the first facet being located at least in part in a first plane and the second facet being located at least in part in a second plane, the first plane and the second plane being transverse to one another; wherein the selected portions of the coil are configured to receive blood flow at respective upstream leading edges, direct first portions of the blood flow over the outer surfaces and second portions of the blood flow across the inner substantially planar surfaces, the first blood flow portions converging with the second blood flow portions at respective trailing edges, the converging first and second blood flow portions at least temporarily directing blood away from the aneurysm bubble and back into the blood vessel.

The present invention in another preferred embodiment contemplates an intra-vascular aneurysm-treatment stent including a flexible coil having a mid- longitudinal axis, insertable into a blood vessel, with selected portions of the coil positioned proximate an opening in a wall of the blood vessel, and opening into an aneurysm bubble, the coil having an upstream proximal end, an opposite

downstream distal end, and a length between the proximal end and the distal end, cross sections of the selected portions in a plane parallel to the mid-longitudinal axis of the coil each having a leading edge directed toward the proximal end, a trailing edge directed toward the distal end, and an outer surface and an inner surface extending from proximate the leading edges to proximate the trailing edges, the outer surfaces each including at least two flattened outer surface portions in the cross sections, a first one of the at least two flattened outer surface portions extending from the trailing edge at least partially toward the proximal end and being angled from, for example, 5° to 80° with respect to a first plane extending between distal-most portions of the leading edges and proximal-most portions of the trailing edges, and a second one of the at least two flattened outer surface portions extending from a leading edge at least partially toward the distal end and being angled from, for example, 5° to 80° with respect to the first plane, a substantially flat first facet being formed on a first portion of the selected portions of the flexible coil adjacent the first one of the at least two flattened outer surface portions, and a substantially flat second facet being formed on the first portion of the selected portions of the flexible coil adjacent the second one of the at least two flattened outer surface portions, the first facet being located at least in part in a second plane and the second facet being located at least in part in a third plane, the second plane and the third plane being transverse to one another, the inner surfaces each including at least two flattened inner surface portions in the cross sections, a first one of the at least two flattened inner surface portions extending from the trailing edge at least partially toward the proximal end and being angled from, for example, 0° to 60° with respect to the first plane, the angles of the first ones of the at least two flattened inner surface portions being less than the angles of the first ones of the at least two flattened outer surface portion, a second one of the at least two flattened inner surface portions extending from the leading edge at least partially toward the distal end and being angled from, for example, 0° to 60° with respect to the first plane, the angles of the second one of the at least two flattened inner surface portions being less than the angles of the second ones of the at least two flattened outer surface portions; wherein the selected portions of the coil are configured to receive blood flow at respective upstream leading edges, direct first portions of the blood flow over the outer surfaces and second portions of the blood flow across the inner surfaces, the first blood flow portions converging with the second blood flow portions at respective trailing edges, the converging first and second blood flow portions at least temporarily directing blood away from the aneurysm bubble and back into the blood vessel. The accompanying Figs. 9-19, which are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 is a side view of a blood vessel, with a saccular aneurysm located on one outer surface of the blood vessel;

Fig. 2 is a side view of a blood vessel with a fusiform aneurysm, defined by a circumferential dilatation of the artery;

Fig. 3A is a perspective view of a coil stent in a blood vessel, used in a conventional attempt to treat a fusiform aneurysm;

Fig. 3B depicts a conventional attempt to treat an aneurysm, using the coil stent of Fig. 3A;

Fig. 4 is a side schematic view depicting the operation of the conventional attempt to treat aneurysms depicted in Fig. 3B, and demonstrating why the conventional attempt is sometimes ineffective;

Fig. 5 is a side view of a flexible intra-vascular stent disclosed in U.S. Serial No. 13/839,775, now U.S. Patent No. 9,339,400, the stent being depicted as positioned in a blood vessel proximate an aneurysm;

Fig. 6A is a side cross-sectional view of a first configuration of the flexible intra-vascular stent of Fig. 5, positioned in a blood vessel proximate an aneurysm;

Fig. 6B is a side cross-sectional view of one coil portion of the flexible intravascular stent of Fig. 6A;

Fig. 6C is an cross-sectional end view of the flexible intra-vascular stent of Fig. 6A, positioned in a blood vessel proximate an aneurysm;

Fig. 7A is a side view of a second configuration of the flexible intra-vascular stent of Fig. 5, positioned in a blood vessel proximate an aneurysm;

Fig. 7B is a cross-sectional end view of one coil portion of the flexible intravascular stent of Fig. 7A;

Fig. 7C is an cross-sectional end view of the flexible intra-vascular stent of Fig. 7A, positioned in a blood vessel proximate an aneurysm;

Fig. 8A is a side view of a blood vessel with a loop defined therein, an aneurysm positioned on a wall of the loop, and the flexible intra-vascular stent of Fig. 5 positioned in the loop proximate the aneurysm; Fig. 8B is a side view of a curved blood vessel, with an aneurysm positioned on a wall of the curve, and the flexible intra-vascular stent of Fig. 5 positioned in the curve proximate the aneurysm;

Fig. 9 is a side cross-sectional view of one coil portion of a first improved embodiment of a flexible intra-vascular stent;

Fig. 10 is a side cross-sectional view of a blood vessel showing that the blood flow in an aneurysm is complex and the flow is at least partially complex, which causes high shear stress along the wall;

Fig. 1 1 A is a side cross-sectional view of the stent of Fig. 9 positioned in a blood vessel adjacent an aneurysm during the systole portion of the heartbeat;

Fig. 1 1 B is a first enlarged portion of Fig. 1 1 A;

Fig. 1 1 C is a second enlarged portion of Fig. 1 1 A;

Fig. 12A is a side cross-sectional view of the stent of Fig. 9 positioned in a blood vessel adjacent an aneurysm during the systole portion of the heartbeat;

Fig. 12B is a first enlarged portion of Fig. 12A;

Fig. 12C is a second enlarged portion of Fig. 12A;

Fig. 13 is a side cross-sectional view of one portion of a second improved embodiment of a flexible intra-vascular stent;

Fig. 14 is a side cross-sectional view of one portion of a third improved embodiment of a flexible intra-vascular stent;

Fig. 15 is a side cross-sectional view of one portion of a fourth improved embodiment of a flexible intra-vascular stent;

Fig. 16 is a side cross-sectional view of one portion of fifth improved embodiment of a flexible intra-vascular stent;

Fig. 17 is a side cross-sectional view of one portion of sixth improved embodiment of a flexible intra-vascular stent

Fig. 18 is a side cross-sectional view of one portion of seventh improved embodiment of a flexible intra-vascular stent; and

Fig. 19. is a side cross-sectional view of one portion of eighth improved embodiment of a flexible intra-vascular stent. DESCRIPTION OF THE EMBODIMENTS

Referring to Figs. 5 - 8B, a flexible coil intra-vascular stent 40/60 disclosed in U.S. Serial No. 13/839,775, now U.S. Patent No. 9,339,400, includes a self- expanding or balloon-expanded generally tubular stent, flexible for going around curves, loops, and corners in blood vessels, particularly carotid or vertebral arteries in the neck, and branch blood vessels leading off the carotid arteries into the brain. The stent 40/60 can be made of flexible wire, and can be formed of a memory metal such as Nitinol. The stent 40/60 can also be formed of a non-memory metal, e.g., stainless steel.

Configurations and operation of the flexible intra-vascular wire stent 40/60 is explained with respect to Figs. 6A - 7C.

As depicted in Fig. 6A, the flexible intra-vascular wire coil stent 40 is positioned in a generally tubular blood vessel 10, the blood vessel 10 including a peripheral inner wall 12, a peripheral outer wall 14, a central lumen 16, and an aneurysm neck 18 in the wall 12, allowing blood 17 to flow from the lumen 16 into an aneurysm bubble 20.

Flexible intra-vascular wire coil stent 40 includes a plurality of sequential coil portions 42, depicted in cross section in Figs. 6A and 6B. As depicted in Figs. 6A and 6B, each coil portion 42 includes an upstream leading edge 44, an outer surface 46, a downstream trailing edge 48, and an inner surface 50. Each outer surface 46 defines an arc between the leading edge 44 and the trailing edge 48, whereas the inner surface 50 is substantially flat. Moreover, whereas several of the outer surfaces 46 face the inner wall 12 of the blood vessel 10, and the inner surfaces 50 all face the lumen 16 of the blood vessel 12, selected coil portions 42' have outer portions 46' facing the neck 18 into the aneurysm 20.

In operation, blood flow 17 in the lumen 16 will flow past the generally flat inner surfaces 50, with some blood flow 17 being diverted by the leading edges 44' of the selected coil portions 42' facing the neck 18, across the outer surfaces 46', past the trailing edges 48' and back towards the lumen 16. Comparing Fig. 6A to Fig.4, it can be seen that rather than directing blood flow into the aneurysm 20, as was the case with the conventional art, selected coil portions 42' direct blood flow away from the aneurysm 20 and toward the lumen 16. Some of the blood 17 in the aneurysm 20 will become entrained in the blood flow 17 over the outer surfaces 46' and be directed back into the lumen 16. More significantly, the converging blood flow paths 17 at the trailing edges 48' of the selected coil portions 42' create eddies 52 proximate the trailing edges 48' of the selected coil portions 42'. Each eddy 52 results in a pressure drop dP between pressure at the respective outer surface 46' and the respective trailing edge 48'. The dP generated at the respective trailing edges 48' will draw blood 17 out of the aneurysm 20 and back into the blood flow 17 in the lumen 16, thereby collapsing the bubble 20, or at least decreasing it.

As depicted in Figs. 7A and 7B, each coil portion 62 of the flexible wire coil intra-vascular stent 60 includes an upstream leading edge 64, an outer surface 66, a downstream trailing edge 68, and an inner surface 70. The outer surface 66 defines a convex surface between the leading edge 64 and the trailing edge 68, whereas the inner surface 70 defines a concave surface between the leading edge 64 and the trailing edge 68. Moreover, whereas several of the outer surfaces 66 face the inner wall 12 of the blood vessel 10, and the inner surfaces 70 all face the lumen 16 of the blood vessel 10, selected coil portions 62' have outer surfaces 66' facing the neck 18 into the aneurysm 20.

In operation, blood flow 17 in the lumen 16 will flow into and out of the concave inner surfaces 70, with some blood flow 17 being diverted by the leading edges 64' of the selected coil portions 62' proximate the neck 18, across the convex outer surfaces 66', past the trailing edges 68' and back towards the lumen 16. As discussed above with respect to Fig. 6A, some of the blood 17 in the aneurysm 20 will become entrained in the blood flow 17 passing across the outer surfaces 66' and will flow back into the lumen 16. More significantly, the converging blood flow paths 17 at the selected trailing edges 68' create eddies 72 proximate the trailing edges 68' of the selected coil portions 62', each eddy 72 resulting in a pressure drop dP between pressure at the respective convex outer surface 66' and the respective trailing edge 68'. In the location of the selected coil portions 62', the dP generated at the respective trailing edges 68' will draw blood 17 out of the aneurysm 20 and back into the blood flow 17 in the lumen 16, thereby collapsing the bubble 20, or at least decreasing it.

Improved embodiments of stents are generally indicated by the numerals 100, 100A, 160, 160A, 200, 200A, 240, and 240A in Figs. 9-19 and are described below. As discussed below, the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A differ from the stents 40/60 in that the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A include a plurality of facets on the outer surfaces and/or the inner surfaces in the side cross sections thereof. The side cross sections of the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A illustrate the arrangement of the facets on outer surfaces and inner surfaces thereof. The facets can be symmetrically or asymmetrically arranged as depicted in the side cross sections of the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A. The facets are symmetrical, as depicted in Figs. 9-15, and the facets are asymmetrical, as depicted in Figs. 16-19. Furthermore, the facets can be formed on the flexible wire and/or can be laser cut into the surfaces of the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A. As discussed below, each of the facets of the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A is configured such that the facets are substantially flat when positioned adjacent an aneurysm neck. Furthermore, one or more of the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A can be used together. Using one or more of the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A involves using different sizes thereof and nesting selected stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A inside one another.

The optimal configuration for the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A is dependent on a multitude of parameters. These parameters include but are not limited to aneurysm size, neck-to-dome ratio, blood viscosity, blood flow velocity, and geometry of the lesion(s) being treated. Geometrical parameters include but are not limited to whether the aneurysm is located on a straight or curved arterial segment, and, because aneurysms rarely form in straight arterial segments, whether the aneurysm is on the inside, outside, or lateral to a curved arterial segment.

Because arterial blood flow is mathematically chaotic and hence, governed by the laws of chaos, the number and arrangement of the facets provided on the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A can be varied. For example, the number of facets, sizes of the facets, and the angles of the facets can be varied to accommodate different flow parameters, which are often unpredictable a priori. Furthermore, stents having different configurations of facets can be tested within blood vessels to determine the optimal configuration thereof to accommodate the above-described parameters.

Each of the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A comprise a self-expanding or balloon-expanded generally tubular stent, flexible for going around curves, loops, and corners in blood vessels, particularly carotid or vertebral arteries in the neck, and branch blood vessels leading off the carotid, vertebral, and basilar arteries within the cranium. The stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A can made of flexible wire, which in a preferred embodiment is formed of a memory metal such as Nitinol. In another preferred embodiment, the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A is formed of a non-memory metal, e.g., stainless steel.

The stents 100, 100A, 160, and 160A, as discussed below, are arranged such that outer surfaces of the stents 100, 100A, 160, and 160A are generally convex in the cross sections depicted in Figs. 9 and 1 1A-15. Furthermore, the stents 100, 100A, 160, and 160A are arranged such that the inner surfaces of the stents 100 and 160 are generally flat in the cross sections depicted in Figs. 9, 1 1A, 12A, and 14, and the stents 100A and 160A are generally concave in the cross sections depicted in Figs. 13 and 15. The convexities of the outer surfaces of the stents 100, 100A, 160, and 160A, the flatness of the inner surfaces of the stents 100 and 160, and the concavities of the inner surfaces of the stents 100A and 160A are formed by one or more of the facets.

As discussed below, the surface configurations of the stents 100, 100A, 160, and 160A provide advantages over the configurations of the stents 40/60. These advantages include but are not limited to the ability to tailor treatment to optimize direction of blood flow away from the aneurysm by sequentially testing several devices with differing cross sections to establish which one— or combination— provides optimal exclusion of blood flow from the aneurysm, and provide an intuitive method of manufacture as an automatable several-step process in which the first step is that of laser-cutting the general stent configuration from a thin tube comprised of a memory metal, and subsequent steps involving angling the work to the laser in order to shape the facets on the struts that are left behind after some or all of the primary laser cutting has been done.

Like the stents 40/60 depicted in Figs. 5, 6A-6C, and 7A-7C, the stent 100 includes a plurality of coil portions 102. The side cross section of a portion of each of the coil portions 102 are represented in Figs. 9, 1 1 A, and 12A. Each of the coil portions 102 includes an upstream leading edge 104, an outer surface 106, a downstream trailing edge 108, an inner surface 1 10, and a longitudinal axis L. For example, the coil portions 102 can be formed from generally ring-shaped portions of the flexible wire or from a winding of generally helical-shaped portions of the flexible wire. Furthermore, the coil portions 102 could be formed via fabrication from a generally cylindrical tube. To illustrate, the fabrication process (such as, for example, laser cutting) could remove portions of the generally cylindrical tube and form, for example, the coil portions 102 as generally ring-shaped portions or generally helical-shaped portions.

Each of the outer surfaces 106 of the coil portions 102 includes a plurality of surface portions, and together, the surface portions form a generally convex shape in cross section. Preferably, the number of surface portions of each of the outer surfaces 106 is at least 2-5, and can range upward from 6-10 to as many as 1 1 -12. The number of surface portions (and corresponding facets) can be adjusted to accommodate the multitude of the above-described parameters. For example, the surface portions of the outer surfaces 106 in the cross section depicted in Fig. 9 can number 5 including a leading first surface portion 1 12A, a leading second surface portion 1 12B, an intermediate third surface portion 1 12C, a trailing fourth surface portion 1 12D, and a trailing fifth surface portion 1 12E. The coil portions 102 each have a radius of curvature extending at least partially around the longitudinal axis L, and thus, locally generally flattened portions of the outer surface 106 are formed immediately adjacent the surface portions 1 12A, 1 12B, 1 12C, 1 12D, and 1 12E. The locally generally flattened portions are facets 1 14A, 1 14B, 1 14C, 1 14D, and 1 14E corresponding to the surface portions 1 12A, 1 12B, 1 12C, 1 12D, and 1 12E, respectively. Additional facets (corresponding to the facets 1 14A, 1 14B, 1 14C, 1 14D, and 1 14E) are formed immediately adjacent additional surface portions (corresponding to the surface portions 1 12A, 1 12B, 1 12C, 1 12D, and 1 12E) in other side cross sections of the coil portions 102.

Each of the inner surfaces 1 10 of the coil portions 102 includes at least one surface portion that forms a generally flat or concave surface shape in the cross section. Preferably, the number of surface portions of each of the inner surfaces 1 10 is at 1 -4, and can range upward from 5-10 to as many as 1 1 -12. The number of surface portions (and corresponding facets) can be adjusted to accommodate the multitude of the above-described parameters. Furthermore, the number of surface portions (and corresponding facets) of the inner surfaces 1 10 can be less than, greater than, or equal to the number of surface portions (and corresponding facets) of the outer surfaces 106. For example, each of the inner surfaces 1 10 includes a surface portion 1 16 that forms a generally flat shape in the cross section depicted in Fig. 9. Given that the coil portions 102 each have a radius of curvature extending at least partially around the longitudinal axis L, a locally generally flattened portion of the inner surface 1 10 is formed immediately adjacent the surface portion 1 16. The locally generally flattened portion is a facet 1 18 corresponding to the surface portion 1 16. Additional facets (corresponding to the facet 1 18) are formed immediately adjacent additional surface portions (corresponding to the surface portion 1 16) in other side cross sections of the coil portions 102.

If the coil portions 102 are formed as generally ring-shaped portions, the surface portions 1 12A, 1 12B, 1 12D, and 1 12E (and the facets 1 14A, 1 14B, 1 14D, and 1 14E) would be portions of frusto-conical surfaces extending around the coil portions 102, and the surface portions 1 12C and 1 16 (and the facets 1 14C and 1 18) would be portions of a cylindrical surface extending around the coil portions 102. Furthermore, if the coil portions 102 are formed as generally helical-shaped portions, the surface portions 1 12A, 1 12B, 1 12C, 1 12D, 1 12E, and 1 16 (and the facets 1 14A, 1 14B, 1 14C, 1 14D, 1 14E, and 1 18) would be portions of helical surfaces extending along the windings of the coil portions 102.

As depicted in Fig. 9, the angles of the surface portions 1 12A and 1 12E with respect to a line extending between the leading edge 104 and the trailing edge 108 is 45°; the angles of the surface portions 1 12B and 1 12D with respect to the line extending between the leading edge 104 and the trailing end 108 is 30°; and the angle of the surface portions 1 12C and 1 18 with respect to the line extending between the leading edge 104 and the trailing edge 108 is 0°. These angles could be varied and still provide for a generally convex shape of each of the outer surfaces 106 and the generally flat shape of each of the inner surfaces 1 10 in cross section. Furthermore, the orientation of the facets 1 14A, 1 14B, 1 14C, 1 14D, 1 14E, and 1 16 would also in part share the angles of the surface portions 1 12A, 1 12B, 1 12C, 1 12D, 1 12E, and 1 18, respectively.

As depicted in FIG. 10, the blood flow 17 in the aneurysm 20 is complex with high shear stress along the wall 22 thereof. The high shear stress is especially acute at the dome 24 of the aneurysm 20. The stent 100 is used to relieve such high shear stress by removing blood from the aneurysm 20.

When the stent 100 is positioned in the blood vessel 10, as depicted in Figs. 1 1A and 12A, the outer surfaces 106 of the coil portions 102 face the inner wall 12 of the blood vessel 10, and the inner surfaces 1 10 of the coil portions 102 face the lumen 16 of the blood vessel 10. Furthermore, selected coil portions 102' have outer surfaces 106' facing the neck 18 into the aneurysm 20. Fig. 1 1A depicts a portion of the blood flow 17 during the diastole portion of the heartbeat where the blood flow 17 will flow into the aneurysm 20 between the selected coil portions 102', and Fig. 12A depicts a portion of the blood flow during the systole portion of the heartbeat where the blood flow 17 flows through the lumen 16 and the selected coil portions 102' function to remove the blood flow 17 from the aneurysm 20.

During the systole portion, the blood flow 17 in the lumen 16 will flow past the inner surfaces 1 10', with some blood flow 17 being diverted by the leading edges 104' of the selected coil portions 102' facing the neck 18, across the outer surfaces 106', past the trailing edges 108', and back towards the lumen 16. Rather than potentially directing the blood flow 17 into the aneurysm 20 (Fig. 4), the selected coil portions 102' directed blood flow away from the aneurysm 20 and toward the lumen 16. Some of the blood 17 in the aneurysm 20 will become entrained in the blood flow 17 over the outer surface 106 and be directed back into the lumen 16.

Furthermore, some of the blood 17 in the aneurysm will be drawn out of the aneurysm and back into the vessel.

The stent 100A depicted in Fig. 13 is similar to the stent 100. The stent 100A includes a plurality of coils 140 having outer surfaces 142 identical to the outer surfaces 106 of the stent 100. However, rather than having an inner surface formed as a generally flat shape in cross section, the plurality of coil portions 140 each have an inner surface 144 including a plurality of surface portions forming a generally concave shape depicted in Fig. 13. Preferably, the number of surface portions of each of the inner surfaces 144 is preferably at least 2-4, and can range upward from 5-10 to as many as 1 1 -12. Furthermore, the number of surface portions (and corresponding facets) of the inner surfaces 144 can be less than, greater than, or equal to the number of surface portions (and corresponding facets) of the outer surfaces 142.

For example, the surface portions of the inner surfaces 144 in the cross section depicted in Fig. 13 each include a leading first surface portion 146A, a leading second surface portion 146B, a trailing third surface portion 146C, and a trailing fourth surface portion 146D. Like, the stent 100, the coil portions 140 each have a radius of curvature extending at least partially around a longitudinal axis of the stent 100A, and thus, locally generally flattened portions of the outer surfaces 144 are formed immediately adjacent the surface portions 146A, 146B, 146C, and 146D. The locally generally flattened portions are facets 148A, 148B, 148C, and 148D corresponding to surface portions 146A, 146B, 146C, and 146D, respectively. Additional facets (corresponding to facets 148A, 148B, 148C, and 148D) are formed immediately adjacent additional surface portions (corresponding to the surface portions 146A, 146B, 146C, and 146D) in other side cross sections of the coil portions 140.

If the coil portions 140 are formed as generally ring-shaped portions, the surface portions 146A, 146B, 146C, and 146D (and the facets 148A, 148B, 148C, and 146C) would be portions of frusto-conical surfaces extending around the coil portions 140. Furthermore, if the coil portions 140 are formed as generally helical- shaped portions, the surface portions 146A, 146B, 146C, and 146D, the surface portions 146A, 146B, 146C, and 146D (and the facets 148A, 148B, 148C, and 148D) would be portions of helical surfaces extending along the windings of the coil portions 140.

As depicted in Fig. 13, the angles of the surface portions 146A and 146D with respect to a line extending between an upstream leading edge 150 and a

downstream trailing edge 152 is 20°; and the angles of the surface portions 146B and 146C with respect to the line extending between the leading edge 150 and the trailing edge 152 is 10°. These angles could be varied and still provide for a generally concave shape each of the inner surfaces 144. Furthermore, the orientation of the facets 148A, 148B, 148C, and 148D would also in part share the angles of the surface portions 146A, 146B, 146C, and 146D.

When placed in the blood flow 17 and positioned in the blood vessel 10 in similar fashion to the stent 100 depicted in Figs. 1 1 A and 12A, the stent 100A would function similarly. That is, by positioning selected coil portions 140 facing the neck 18, some of the blood flow 17 diverted by selected leading edges 150, across selected outer surfaces 142, past selected trailing edges 152, and back towards the lumen 16. Furthermore, some of the blood 17 in the aneurysm will be drawn out of the aneurysm and back into the vessel.

The stent 160 depicted in Fig. 14 is similar to the stent 100. The stent 160 includes a plurality of coil portions 162 of which the side cross section of a portion of each of the coil portions 162 are represented in Fig. 14. Each of the coil portions 162 includes an upstream leading edge 164, an outer surface 166, a downstream trailing edge 168, and an inner surface 170.

Rather than having 5 surface portions like the stent 100 in cross section, the outer surfaces of 166 of the stent 160 depicted in cross section in Fig. 14 includes 4 surface portions that together form a generally convex shape. The preferable number of surface portions of the upper surfaces 166 can alternatively have the same range as for the stent 100. For example, the surface portions of the outer surfaces 166 can include a leading first surface portion 172A, a leading second surface portion 172B, a leading third surface portion 172C, and a leading fourth surface portion 172D. Like, the stent 100, the coil portions 162 each have a radius of curvature extending at least partially around a longitudinal axis of the stent 160, and thus, locally generally flatted portions of the outer surface 166 are formed immediately adjacent the surface portions 172A, 172B, 172C, and 172D. The locally generally flattened portions are facets 174A, 174B, 174C, and 174D corresponding to the surface portions 172A, 172B, 172C, and 172D, respectively. Additional facets (corresponding to the facets 174A, 174B, 174C, and 174D) are formed immediately adjacent additional surface portions (corresponding to the surface portions 172A, 172B, 172C, and 172D) in other side cross sections of the coil portions 162.

Each of the inner surfaces 170 of the coil portions 162 includes at least one surface portion that forms a generally flat or concave surface shape in cross section. For example, each of the inner surfaces 170 includes a surface portion 176 that forms a generally flat shape in the cross section depicted in Fig. 14. Given that the coil portions 162 each have a radius of curvature extending at least partially around a longitudinal axis of the stent 160, a locally generally flattened portion of the inner surface 170 is formed immediately adjacent the surface portion 176. The locally generally flattened portion is a facet 1 18 corresponding to the surface portion 176. Additional facets (corresponding to the facet 1 18) are formed immediately adjacent additional surface portions (corresponding to the surface portion 176) in other side cross sections of the coil portions 162.

If the coil portions 162 are formed as generally ring-shaped portions, the surface portions 172A, 172B, 172C, and 172D (and the facets 174A, 174B, 174C, and 174D) would be portions of frusto-conical surfaces extending around the coil portions 162, and the surface portions 176 would be portions of a cylindrical surface extending around the coil portions 162. Furthermore, if the coil portions 162 are formed as generally cylindrical portions, the surface portions 172A, 172B, 172C,

172D, and 176 (and the facets 174A, 174B, 174C, 174D, and 176) would be portions of helical surface extending along the windings of the coil portions.

As depicted in FIG. 14, the angles of the surface portions 172A and 172D with respect to a line extending between the leading edge 164 and the trailing edge 168 is 45°, the angles of the surface portions 172B and 172C with respect to the line extending between the leading edge 164 and the trailing edge 168 is 30°, and the angle of the surface portion 176 with respect to the line extending between the leading edge 164 and the trailing edge 168 is 0°. These angles could be varied and still provide for a generally convex shaped of each of the outer surface 166 and the generally flat shape of each of the inner surfaces 170 in cross section. Furthermore, the orientation of the facets 174A, 174B, 174C, 174D, and 178 would also in part share the angels of the surface portions 172A, 172B, 172C, 172D, and 176.

When placed in the blood flow 17 and positioned in the blood vessel 10 in similar fashion to the stent depicted in Figs. 1 1A and 12A, the stent 160 would function similarly. That is, by positioned selected coil portions 162 facing the neck 18, some of the blood flow 17 diverted by selected leading edges 164, across selected outer surfaces 166, passed selected trailing edges 168, and back towards the lumen 16. Furthermore, some of the blood 17 in the aneurysm will be drawn out of the aneurysm and back into the vessel.

The stent 160A depicted in Fig. 15 is similar to the stent 160. The stent 160A includes a plurality of coils 180 having outer surfaces 182 identical to the outer surfaces 166 of the stent 160. However, rather than having an inner surface formed as a generally flat shape in cross section, the plurality of coil portions 180 each have an inner surface 184 including a plurality of surface portions forming a generally concave shape depicted in Fig. 15. Preferably, the number of surface portions of each of the inner surfaces 144 is preferably at least 2-3, and can range upward from 4-10 to as many as 1 1 -12. Furthermore, the number of surface portions (and corresponding facets) of the inner surfaces 184 can be less than, greater than, or equal to the number of surface portions (and corresponding facets) of the outer surfaces 182.

For example, the surface portions of the inner surfaces 184 in the cross section depicted in Fig. 15 each include a leading first surface portion 186A, an intermediate second surface portion 186B, and a trailing third surface portion 186C. Like, the stent 160, the coil portions 180 each have a radius of curvature extending at least partially around a longitudinal axis of the stent 160A, and thus, locally generally flattened portions of the outer surfaces 144 are formed immediately adjacent the surface portions 186A, 186B, and 186C. The locally generally flattened portions are facets 188A, 188B, and 188C corresponding to surface portions 186A, 186B, and 186C, respectively. Additional facets (corresponding to facets 188A, 188B, and 188C) are formed immediately adjacent additional surface portions (corresponding to the surface portions 186A, 186B, and 186C) in other side cross sections of the coil portions 180.

If the coil portions 180 are formed as generally ring-shaped portions, the surface portions 166A, 166B, and 166C (and the facets 168A, 168B, and 168C) would be portions of frusto-conical surfaces extending around the coil portions 180. Furthermore, if the coil portions 140 are formed as generally helical-shaped portions, the surface portions 186A, 186B, and 186C (and the facets 188A, 188B, and 188C) would be portions of helical surfaces extending along the windings of the coil portions 180.

As depicted in Fig. 13, the angles of the surface portions 186A and 186C with respect to a line extending between an upstream leading edge 190 and a

downstream trailing edge 192 is 15°; and the angle of the surface portion 186C with respect to the line extending between the leading edge 190 and the trailing edge 192 is 0°. These angles could be varied and still provide for a generally concave shape each of the inner surfaces 184. Furthermore, the orientation of the facets 188A, 188B, and 188C would also in part share the angles of the surface portions 186A, 186B, and 186C.

When placed in the blood flow 17 and positioned in the blood vessel 10 in similar fashion to the stent 100 depicted in Figs. 1 1 A and 12A, the stent 160A would function similarly. That is, by positioning selected coil portions 180 facing the neck 18, some of the blood flow 17 diverted by selected leading edges 190, across selected outer surfaces 182, past selected trailing edges 192, and back towards the lumen 16. Furthermore, some of the blood 17 in the aneurysm will be drawn out of the aneurysm and back into the vessel.

Additional improved embodiments of stents are generally indicated by the numerals 200, 200A, 240, and 240A in Figs. 16-19 and are described below. Like the stents 100, 100A, 160, and 160A, the stents 200, 200A, 240, and 240A include a plurality of facets on the outer surfaces and/or the inner surfaces in the side cross sections thereof. The side cross sections of the stents 200, 200A, 240, and 240A in Figs. 16-19 illustrate the arrangement of the facets. As depicted in Figs. 16-19, the facets can be arranged asymmetrically on outer surfaces and/or inner surfaces as depicted in the side cross sections of the stents 200, 200A, 240, and 240A.

Furthermore, the facets can be formed on the flexible wire and/or can be laser cut into the surfaces of the stents 200, 200A, 240, and 240A. As discussed below, each of the facets of the stents stents 200, 200A, 240, and 240A is configured such that the facets are substantially flat when positioned adjacent an aneurysm neck.

Furthermore, one or more of the stents 200, 200A, 240, and 240A, as well as the stents 100, 100A, 160, and 160A) can be used together. Using one or more of the stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A involves using different sizes thereof and nesting selected stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A inside one another.

Also, the asymmetrical arrangement of the facets of the stents 200, 200A, 240, and 240A can be combined with the symmetrical arrangement of the facets of the stents 100, 100A, 160, and 160A. That is, the symmetrical arrangement of the facets of the stents 100, 100A, 160, and 160A on the outer surfaces thereof can be used with the asymmetrical arrangement of the facets of the stents 200, 200A, 240, and 240A on the inner surfaces thereof, and vice versa.

The stents 200, 200A, 240, and 240A function in similar fashion to the stents 100, 100A, 160, and 160A to create the above-discussed eddies and corresponding pressure drops.

As depicted in Fig. 16, the stent 200 includes in various cross sections thereof a coil portion 202, a leading edge 204, an outer surface 206, a trailing edge 208, and an inner surface 210. In similar fashion to those of the stents 100, 100A, 160, and 160A, the outer surface 206 includes surface portions 212A, 212B, 212C, 212D, and 212E, and corresponding facets 214A, 214B, 214C, 214D, and 214E. And in similar fashion to stents 100 and 160, the inner surface 210 includes a surface portion 216 and a corresponding facet 218. However, in contrast to the stents 100, 100A, 160, and 160A, as depicted in Figs. 9-15, the outer surface 206 includes an asymmetrical arrangement of the surface portions 212A, 212B, 212C, 212D, and 212E (and corresponding facets 214A, 214B, 214C, 214D, and 214E). Preferably, the number of surface portions (and corresponding facets) of the outer surfaces 206 is at least 2-5, and can preferably range upward from 6-10 to as many as 1 1 -12. Furthermore, the number of surface portions (and corresponding facets) of the inner surfaces 210 can be less than, greater than, or equal to the number of surface portions (and corresponding facets) of the outer surfaces 206. The number of surface portions (and corresponding facets) can be adjusted to accommodate a multitude of the above-described parameters. Moreover, the angles of the surface portions 212A, 212B, 212C, 212D, and 212E (and the corresponding facets 214A, 214B, 214C, 214D, and 214E) can be varied between 0° and 90°, where preferably the angles decrease as the outer surfaces approach the maximum heights relative to the inner surface 210. The angles can also be adjusted to accommodate a multitude of the above-described parameters.

As depicted in Fig. 17, the stent 200A includes in various cross sections thereof a coil portion 222, a leading edge 224, an outer surface 226, a trailing edge 228, and an inner surface 230. In similar fashion to those of the stents 100, 100A, 160, and 160A, the outer surface 226 includes surface portions 232A, 232B, 232C, 232D, and 232E, and corresponding facets 234A, 234B, 234C, 234D, and 234E arranged at angles identical to those of the stent 200. And in similar fashion to stents 100A and 160A, the inner surface 230 includes surface portions 236A and 236B, and corresponding facets 238A and 238B. However, in contrast to the stents 100, 100A, 160, and 160A, as depicted in Figs. 9-15, the outer surface 226 and the inner surface 230 includes an asymmetrical arrangement of the surface portions 232A, 232B, 232C, 232D, 232E, 236A, and 236B (and corresponding facets 234A, 234B, 234C, 234D, 234E, 238A, and 238B).

Preferably, the number of surface portions (and corresponding facets) of the outer surfaces 226 is at least 2-5, and can preferably range upward from 6-10 to as many as 1 1 -12. Furthermore, the number of surface portions (and corresponding facets) of the inner surfaces 230 can be less than, greater than, or equal to the number of surface portions (and corresponding facets) of the outer surfaces 226. The number of surface portions (and corresponding facets) can be adjusted to accommodate a multitude of the above-described parameters. Moreover, the angles of the surface portions 232A, 232B, 232C, 232D, and 232E (and the corresponding facets 234A, 234B, 234C, 234D, and 234E) and of the surface portions 236A and 236B (and the corresponding facets 238A and 238B) can be varied between 0° and 90°, where preferably the angles decrease as the outer surfaces and the inner surfaces approach the maximum heights relative to a plane extending between the leading edge 224 and the trailing edge 228. The angles can also be adjusted to accommodate a multitude of the above-described parameters.

As depicted in Fig. 18, the stent 240 includes in various cross sections thereof a coil portion 242, a leading edge 244, an outer surface 246, a trailing edge 248, and an inner surface 250. In similar fashion to those of the stents 100, 100A, 160, and 160A, the outer surface 246 includes surface portions 252A, 252B, 252C, 252D, and 252E, and corresponding facets 254A, 254B, 254C, 254D, and 254E. And in similar fashion to the stents 100 and 160, the inner surface 250 includes a surface portion 256 and a corresponding facet 258. However, in contrast to the stents 100, 100A, 160, and 160A, as depicted in Figs. 9-15, the outer surface 246 includes an asymmetrical arrangement of the surface portions 252A, 252B, 252C, 252D, and 252E (and corresponding facets 254A, 254B, 254C, 254D, and 254E).

Preferably, the number of surface portions (and corresponding facets) of the outer surfaces 246 is at least 2-5, and can preferably range upward from 6-10 to as many as 1 1 -12. Furthermore, the number of surface portions (and corresponding facets) of the inner surfaces 250 can be less than, greater than, or equal to the number of surface portions (and corresponding facets) of the outer surfaces 246. The number of surface portions (and corresponding facets) can be adjusted to accommodate a multitude of the above-described parameters. Moreover, the angles of the surface portions 252A, 252B, 252C, 252D, and 252E (and corresponding facets 254A, 254B, 254C, 254D, and 254E) can be varied between 0° and 90°, where preferably the angles decrease as the outer surfaces approach the maximum heights relative to the inner surface 250. The angles can also be adjusted to accommodate a multitude of the above-described parameters.

As depicted in Fig. 19, the stent 200A includes in various cross sections thereof a coil portion 262, a leading edge 264, an outer surface 266, a trailing edge 268, and an inner surface 270. In similar fashion to those of the stents 100, 100A, 160, and 160A, the outer surface 266 includes surface portions 272A, 272B, 272C, 272D, and 272E, and corresponding facets 274A, 274B, 274C, 274D, and 274E arranged at angles identical to those of the stent 240. And in similar fashion to stents 100A and 160A, the inner surface 270 includes surface portions 276A, 276B, and 276C, and corresponding facets 278A, 278B, and 278C. However, in contrast to the stents 100, 100A, 160, and 160A, as depicted in Figs. 9-15, the outer surface 266 and the inner surface 270 includes an asymmetrical arrangement of the surface portions 272A, 272B, 272C, 272D, 272E, 276A, 276B, and 276C (and corresponding facets 274A, 274B, 274C, 274D, 274E, 278A, 278B, and 278C).

Preferably, the number of surface portions (and corresponding facets) of the outer surfaces 266 is at least 2-5, and can preferably range upward from 6-10 to as many as 1 1 -12. Furthermore, the number of surface portions (and corresponding facets) of the inner surfaces 270 can be less than, greater than, or equal to the number of surface portions (and corresponding facets) of the outer surfaces 266. The number of surface portions (and corresponding facets) can be adjusted to accommodate a multitude of the above-described parameters. Moreover, the angles of the surface portions 272A, 272B, 272C, 272D, and 272E (and the corresponding facets 274A, 274B, 274C, 274D, and 274E) and of the surface portions 276A, 276B, and 276C(and the corresponding facets 278A, 278B, and 278C) can be varied between 0° and 90°, where preferably the angles decrease as the outer surfaces and the inner surfaces approach the maximum heights relative to a plane extending between the leading edge 264 and the trailing edge 268. The angles can also be adjusted to accommodate a multitude of the above-described parameters.

As previously addressed, because arterial blood flow is mathematically chaotic and hence, governed by the laws of chaos, the number and arrangement of the facets provided on the stents, such as stents 100, 100A, 160, 160A, 200, 200A, 240, and 240A can be varied. For example, the number of facets, sizes of the facets, and the angles of the facets can be varied to accommodate different flow parameters, which are often unpredictable a priori. Furthermore, stents having different configurations of facets can be tested within blood vessels to determine the optimal configuration thereof to accommodate the above-described parameters.

A preferred embodiment of a trial stent or a stent for insertion permanently into a patient includes different cross-sectional designs on the outer surfaces and/or the inner surfaces either along the length of the stent or along different arcs of radius of the stent. By way of example, a trial stent could have a cross-sectional configuration similar to that depicted in Fig. 9 along the first quarter of the length of the stent, a cross-sectional configuration similar to that depicted in Fig. 13 along the second quarter of the length of the stent, a cross-sectional configuration similar to that depicted in Fig. 14 along the third quarter of the length of the stent, and finally a cross-sectional configuration similar to that depicted in Fig. 15 along the fourth quarter of the length of the stent. A stent with such a configuration would permit a surgeon to advance the stent to a position proximate the aneurysm at each of the four positions along the length of the stent in an effort to optimize redirecting blood flow out of the aneurysm. While this example of the stent has four different test zones for placement proximate the aneurysm, the stent could be formed with as few as two different configuration of cross sections along the length of the stent or alternatively have three zones or five or more zones. The zones in a preferred embodiment are of approximately equal lengths although the zones may be of different lengths from one another.

Yet another preferred embodiment of a trial stent or a stent for insertion permanently into a patient includes different cross-sectional designs on the outer surfaces and/or the inner surfaces along different arcs of radius of the stent. In particular it is contemplated that the stent could have an upper portion covering 180 degrees of the stent having a first cross-sectional design on the outer surfaces and/or the inner surfaces and could have an lower portion covering 180 degrees of the stent having a second cross-sectional design on the outer surfaces and/or the inner surfaces so as to permit a surgeon to rotate each of the upper half and then the lower half of the stent to proximate the aneurysm in an effort to optimize redirecting blood flow out of the aneurysm. Alternatively the trial stent or the stent for insertion permanently into a patient may be divided into arcs of radius of 120 degrees for three different configurations or into arcs of radius of 90 degrees for four different configurations or even more than four arcs of radius. While the arcs of radius have been described as being approximately equal to one another, in a further preferred embodiment the arcs of radius may be of different degrees from one another.

While the preferred embodiment of a trial stent or a stent for insertion permanently into a patient having different cross-sectional designs on the outer surfaces and/or the inner surfaces either along the length of the stent or along different arcs of radius of the stent have been described with general reference, by way of example, to Figs. 9 through 15, it is contemplated that these embodiments may be used in association with facets that are symmetrical and with facets are asymmetrical, such as depicted in Figs. 16-19. It is further contemplated that a trial stent or a stent for insertion permanently into a patient having different cross- sectional designs on the outer surfaces and/or the inner surfaces either along the length of the stent or along different arcs of radius of the stent may be formed in whole or in part with cross-sectional configurations disclosed in the present application, in whole or in part with cross-sectional configurations disclosed in U.S. Patent No. 9,339,400, or in whole or in part with any other configurations know in the art so that a surgeon may either linearly advance or rotate the stent to proximate the aneurysm in an effort to optimize redirecting blood flow out of the aneurysm.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

WHAT IS CLAIMED IS:

An intra-vascular aneurysm-treatment stent comprising:

a flexible coil having a mid-longitudinal axis, insertable into a blood vessel, with selected portions of the coil positioned proximate an opening in a wall of the blood vessel, and opening into an aneurysm bubble, the coil having an upstream proximal end, an opposite downstream distal end, and a length between the proximal end and the distal end, cross sections of the selected portions in a plane parallel to the mid-longitudinal axis of the coil each having a leading edge directed toward the proximal end, a trailing edge directed toward the distal end, and an outer surface and an inner substantially planar surface extending from proximate the leading edges to proximate the trailing edges, the outer surfaces each including at least two flattened surface portions in the cross sections,

a first one of the at least two flattened surface portions extending from the trailing edge at least partially toward the proximal end and being angled from 5° to 80° with respect to the corresponding inner substantially planar surface, and

a second one of the at least two flattened surface portions extending from the leading edge at least partially toward the distal end and being angled from 5° to 80° with respect to the corresponding inner substantially planar surface,

a substantially flat first facet being formed on a first portion of the selected portions of the flexible coil adjacent the first one of the at least two flattened surface portions, and

a substantially flat second facet being formed on the first portion of the selected portions of the flexible coil adjacent the second one of the at least two flattened surface portions,

the first facet being located at least in part in a first plane and the second facet being located at least in part in a second plane, the first plane and the second plane being transverse to one another;

wherein the selected portions of the coil are configured to receive blood flow at respective upstream leading edges, direct first portions of the blood flow over the outer surfaces and second portions of the blood flow across the inner substantially planar surfaces, the first blood flow portions converging with the second blood flow portions at respective trailing edges, the converging first and second blood flow portions at least temporarily directing blood away from the aneurysm bubble and back into the blood vessel.

The stent of claim 1 , wherein the first one and the second one of the at least two flattened surface portions intersect one another in each of the cross sections of the selected portions of the flexible coil, maximum heights of the selected portions of the flexible coil being located in planes perpendicular to the inner substantially planar surfaces and extending through the intersections of the first one and the second one of the at least two flattened surface portions.

The stent of claim 2, wherein the planes perpendicular to the inner substantially planar surfaces and extending through the intersections of the first one and the second one of the at least two flattened surface portions extend through the inner substantially planar surfaces halfway between intersections between the leading edges and the substantially planar inner surfaces and the intersections between the trailing edges and the

substantially planar inner surfaces.

The stent of claim 2, wherein the planes perpendicular to the inner substantially planar surfaces and extending through the intersections of the first one and the second one of the at least two flattened surface portions extend through the inner substantially planar surfaces one of between intersections between the leading edges and the substantially planar inner surfaces and halfway points between distal-most portions of the leading edges and proximal-most portions of the trailing edges, and between intersections between the trailing edges and the substantially planar inner surfaces and the halfway points between the distal-most portions of the leading edges and the proximal-most portions of the trailing edges.

The stent of claim 1 , wherein the first and second ones of the at least two flattened surface portions of each of the outer surfaces intersect one another. The stent of claim 1 , wherein the outer surfaces each further include a third one of the at least two flattened surface portions in the cross sections, the third one of the at least two flattened surface portions extending from the first one of the at least two flattened surface portions at least partially toward the proximal end and being angled from 0° to 60° with respect to the

corresponding inner substantially planar surface.

7. The stent of claim 6, wherein the outer surfaces each further include a fourth one of the at least two flattened surface portions in the cross sections, the fourth one of the at least two flattened surface portions extending from the second one of the at least two flattened surface portions at least partially toward the distal end and being angled from 0° to 60° with respect to the corresponding inner substantially planar surface.

8. The stent of claim 7, wherein the third and fourth ones of the at least two flattened surface portions of each of the outer surfaces intersect one another.

9. The stent of claim 1 , wherein the selected coil portions are configured to

define eddies in the blood flow path proximate each of the trailing edges.

10. An intra-vascular aneurysm-treatment stent comprising:

a flexible coil having a mid-longitudinal axis, insertable into a blood vessel, with selected portions of the coil positioned proximate an opening in a wall of the blood vessel, and opening into an aneurysm bubble, the coil having an upstream proximal end, an opposite downstream distal end, and a length between the proximal end and the distal end, cross sections of the selected portions in a plane parallel to the mid-longitudinal axis of the coil each having a leading edge directed toward the proximal end, a trailing edge directed toward the distal end, and an outer surface and an inner surface extending from proximate the leading edges to proximate the trailing edges,

the outer surfaces each including at least two flattened outer surface portions in the cross sections,

a first one of the at least two flattened outer surface portions extending from the trailing edge at least partially toward the proximal end and being angled from 5° to 80° with respect to a first plane extending between distal- most portions of the leading edges and proximal-most portions of the trailing edges, and

a second one of the at least two flattened outer surface portions extending from a leading edge at least partially toward the distal end and being angled from °5 to 80° with respect to the first plane, a substantially flat first facet being formed on a first portion of the selected portions of the flexible coil adjacent the first one of the at least two flattened outer surface portions, and

a substantially flat second facet being formed on the first portion of the selected portions of the flexible coil adjacent the second one of the at least two flattened outer surface portions,

the first facet being located at least in part in a second plane and the second facet being located at least in part in a third plane, the second plane and the third plane being transverse to one another,

the inner surfaces each including at least two flattened inner surface portions in the cross sections,

a first one of the at least two flattened inner surface portions extending from the trailing edge at least partially toward the proximal end and being angled from 0° to 60° with respect to the first plane, the angles of the first ones of the at least two flattened inner surface portions being less than the angles of the first ones of the at least two flattened outer surface portion, a second one of the at least two flattened inner surface portions extending from the leading edge at least partially toward the distal end and being angled from 0° to 60° with respect to the first plane, the angles of the second one of the at least two flattened inner surface portions being less than the angles of the second ones of the at least two flattened outer surface portions;

wherein the selected portions of the coil are configured to receive blood flow at respective upstream leading edges, direct first portions of the blood flow over the outer surfaces and second portions of the blood flow across the inner surfaces, the first blood flow portions converging with the second blood flow portions at respective trailing edges, the converging first and second blood flow portions at least temporarily directing blood away from the aneurysm bubble and back into the blood vessel.

The stent of claim 10, further comprising a substantially flat third facet formed on the first portion of the selected portions of the flexible coil adjacent the first one of the at least two flattened inner surface portions, and a substantially flat fourth facet formed on the first portion of the selected portions of the flexible coil adjacent the second one of the at least two flattened inner surface portions.

12. The stent of claim 1 1 , wherein the third facet is located at least in part in a fourth plane and the fourth facet is located at least in part in a fifth plane, the fourth plane and the fifth plane being transverse to one another.

13. The stent of claim 12, wherein the fourth plane is transverse to the third plane, and the fifth plane is transverse to the second plane.

14. The stent of claim 10, wherein the first one and the second one of the at least two flattened outer surface portions intersect one another in each of the cross sections of the selected portions of the flexible coil, maximum heights of the selected portions of the flexible coil being located in planes perpendicular to the first plane and extending through the intersections of the first one and the second one of the at least two flattened surface portions.

15. The stent of claim 14, wherein the planes perpendicular to the first plane and extending through the intersections of the first one and the second one of the at least two flattened surface portions extend through the first planes halfway between intersections between the leading edges and the inner surfaces and the intersections between the trailing edges and the inner surfaces.

16. The stent of claim 14, wherein the planes perpendicular to the first plane and extending through the intersections of the first one and the second one of the at least two flattened surface portions extend through the first planes one of between intersections between the leading edges and the inner surfaces and halfway points on the first planes between distal-most portions of the leading edges and proximal-most portions of the trailing edges, and between intersections between the trailing edges and the inner surfaces and the halfway points on the first planes between the distal-most portions of the leading edges and the proximal-most portions of the trailing edges.

17. The stent of claim 10, wherein the first and second ones of the at least two flattened outer surface portions of each of the outer surface intersect one another.

18. The stent of claim 10, wherein the outer surfaces each further include a third one of the at least two flattened outer surface portions in the cross sections, the third one of the at least two flattened outer surface portions extending from the first one of the at least two flattened outer surface portions at least partially toward the proximal end and being angled from 0° to 60° with respect to the corresponding inner substantially planar surface.

19. The stent of claim 18, wherein the outer surfaces each further include a fourth one of the at least two flattened outer surface portions in the cross sections, the fourth one of the at least two flattened outer surface portions extending from the second one of the at least two flattened outer surface portions at least partially toward the distal end and being angled from 0° to 60° with respect to the corresponding inner substantially planar surface.

20. The stent of claim 19, wherein the third and fourth ones of the at least two flattened outer surface portions of each of the outer surfaces intersect one another.