Aortic stent, stent system, and methods of implanting stents

Abstract

The present disclosure provides a stent for an aorta, the stent having a longitudinal axis defined between a first end and a second end of the stent. In the radially expanded state, the second end has an oval cross-sectional shape in a plane perpendicular to the longitudinal axis. The stent comprises first and second radiopaque markers. There is also provided a stent system comprising the stent for an aorta as a first stent, and a second stent for crossing over the common iliac arteries. The second stent has an aperture between its first and second ends, and the first stent is configured to couple to the second stent. A method of implanting the stent is provided. A method of implanting the stent system is also provided.

Description

[0001] Angiomed GmbH & Co . Medi zintechnik KG 253 766 t! 0 / v9 / rco

[0002] Aortic Stent, Stent System, and Methods of Implanting Stents

[0003] Field of the Invention

[0004] A stent for an aorta and a method of implanting a stent in an aorta are provided. A system comprising the stent for an aorta and a second stent is also provided. A method of implanting the stent is provided. A method of implanting the stent system is also provided.

[0005] Background

[0006] Aortoiliac occlusive disease occurs when deposits, such as calcium, build up in the aorta or build up in and around the aortoiliac bifurcation. These deposits can impede blood flow and can lead to numerous symptoms including pain, numbness, or cramping in the lower limbs, and gangrene in the feet.

[0007] In cases where deposits have built up in the inferior end of the (descending) aorta, i.e., proximate to the aortoiliac bifurcation, a stent or “aortic stent” may be implanted in this region. The deposits typically partially occlude the aorta, leaving only a narrow passage for blood flow. The stent is inserted in a radially-compact state through this narrowed passage. The stent is then transitioned to a radially- expanded state in which the stent presses radially outward on the deposits and provides a wider path for blood flow through a central lumen of the stent.

[0008] Deposits can also build up in the aortoiliac bifurcation itself, possibly in addition to build-up of deposits in the aorta. One established treatment for this condition is to implant kissing stents in the aortoiliac bifurcation. In this procedure, a first stent is implanted that crosses from the aorta to one of the right and left common iliac arteries, and a second stent is then implanted that crosses from the aorta to the other of the right and left common iliac arteries. The superior ends of the two stents are generally positioned to be immediately adjacent one another or touching one another, with said ends located either within the inferior end of the aorta or within the aortoiliac bifurcation itself - the exact placement may be determined by clinical indications. In this arrangement, the stents are referred to in the art as “kissing stents.” Once implanted, one kissing stent provides a now-widened passage for blood from the aorta to the right common iliac artery, and the other kissing stent provides a now-widened passage for blood from the aorta to the left common iliac artery. In this way, proper blood flow through the aorta and into the common iliac arteries may be restored. 253 766 t! 0 / v9 / rco

[0009] It is desirable to reduce the number of accesses into a patient’s vasculature during surgery to treat aortoiliac occlusive disease, as each access is a further infection risk and a further location that needs to heal after surgery. Thus, there is need in the art for improved apparatuses and methods for treating aortoiliac occlusive disease.

[0010] Summary of Invention

[0011] According to a first aspect, there is provided a stent for an aorta, the stent having a longitudinal axis defined between a first end and a second end of the stent, the stent being transitionable from a radially compact state to a radially expanded state. In the radially expanded state, the second end has an oval cross-sectional shape in a plane perpendicular to the longitudinal axis. The stent comprises first and second radiopaque markers, the radiopaque markers for determining a rotational orientation of the stent in the radially compact state. The oval of the cross-section has a major axis and a minor axis, wherein the first radiopaque marker intersects a first point on the oval, wherein the second radiopaque marker intersects a second point on the oval, wherein the first point is symmetrical with the second point across the minor axis or the major axis.

[0012] The first point and second point are at a common height along the longitudinal axis. That is, a first radial line that connects the longitudinal axis to the first point and a second radial line connecting the longitudinal axis to the second point touch one another at a common point on the longitudinal axis.

[0013] The inferior end of the aorta has a generally oval cross section in the region proximate to the aortoiliac bifurcation and the aortoiliac bifurcation has a generally oval cross section as well, when these regions are not obstructed by deposits, such as in aortoiliac occlusive disease. The oval’s major axis is oriented generally in the patient’s lateral axis, i.e., from the patient’s left to their right. Providing a stent having an oval cross-section at (at least) one end means that, when expanded, the stent more-closely matches the original geometry of the aorta / aortoiliac bifurcation in this region. The oval cross section of the stent, in the expanded state, should of course be aligned with the original oval cross section of the aorta. The radiopaque markers allow the rotational orientation of the stent to be determined under imaging before expansion of the stent into its radially expanded state. Thus, a user (e.g., physician) can properly orient the stent while it 253 766 t! 0 / v9 / rco is in the radially compact state, such that, once in the radially-expanded state, the oval cross-section of the stent is aligned with the oval cross section of the aorta / aortoiliac bifurcation in this region.

[0014] In one surgical procedure, the imaging is performed along the patient’s anterior- posterior axis, i.e. , from their front towards their back. That is, typically, the patient is lying on their back on the surgical table and an imaging device is positioned on or above the patient’s the chest, pointing towards their back. The imaging device images the patient from front to back and this allows an operator (e.g., physician) to see where the stent is located as it is being inserted from an access, through the vasculature, to the desired implantation location in the aorta. The imaging device thus images along a given imaging axis. Under imaging, the radiopaque markers will appear as two markers that are spaced along the lateral axis at some orientations of the stent. The markers allow the physician to determine the rotational orientation of the stent. For example, at two particular orientations (180 degrees apart), the two markers will overlap one another while being imaged along the imaging axis and will thus appear as a single marker.

[0015] The first point may be symmetrical with the second point across the major axis, and wherein the first point intersects the minor axis, and the second point intersects the minor axis.

[0016] The first point may be symmetrical with the second point across the major axis, and wherein the first point does not intersect the minor axis and the second point does not intersect the minor axis.

[0017] The first point may be symmetrical with the second point across the minor axis, and wherein the first point intersects the major axis, and the second point intersects the major axis.

[0018] The first point may be symmetrical with the second point across the minor axis, and wherein the first point does not intersect the major axis and the second point does not intersect the major axis.

[0019] The first point and second point may be located proximate to the second end or at the second end. 253 766 t! 0 / v9 / rco

[0020] The first point and the second point may be located between the first end and the second end.

[0021] The first radiopaque marker may comprise a first line extending substantially along the longitudinal axis, and the second radiopaque marker may comprise a second line extending substantially circumferentially around the stent.

[0022] The stent may comprise one or more wires forming a scaffold, and wherein a first portion of the one or more wires is made of a radiopaque material and forms the first radiopaque marker, and wherein a second portion of the one or more wires is made of a radiopaque material and forms the second radiopaque marker, wherein other portions of the one or more wires are less radiopaque than either the first or second radiopaque markers.

[0023] The stent may comprise one or more wires forming a scaffold, and a cover extending at least partially over the scaffold.

[0024] According to a second aspect, there is provided a stent system comprising: a first stent that is the stent according to the first aspect, and a second stent that is transitionable between a radially compact state and a radially expanded state; the second stent comprising a wall extending between a first end of the second stent and a second end of the second stent, wherein an aperture is formed in the wall between the first and second ends of the second stent; wherein, the first stent is configured to couple to the second stent, and when the first stent and second stent are each in the expanded state, the oval cross section of the second end of the first stent is larger than the aperture.

[0025] When both the first stent and second stent are in their respective expanded states, the second end of the first stent may be larger than the aperture such that the first stent cannot pull out of the second stent without deforming one or both of the stents.

[0026] The aperture may be oval shaped, wherein the oval shape of the aperture conforms to an outer surface of the first stent at a predetermined height along the longitudinal axis of the first stent. 253 766 t! 0 / v9 / rco

[0027] The second stent may comprise a chimney portion, and the aperture is formed at an end of the chimney portion. The first stent may solely contact the second stent solely at the chimney portion.

[0028] The first stent may be a covered stent and / or the second stent may be a covered stent.

[0029] According to a third aspect, there is provided a catheter containing the stent system of the preceding aspect, wherein the catheter has a distal end, wherein the first sent and second stent are each in their radially compact state, and wherein the second stent is located proximate to the distal end, and wherein the first stent is located proximal of the second stent.

[0030] According to a fourth aspect, there is provided a method of implanting a stent in an aorta, the method comprising: a step of advancing a catheter containing a stent through a patient’s vasculature; wherein the stent the stent has a longitudinal axis defined between a first end and a second end of the stent, the stent being transitionable from a radially compact state to a radially expanded state; wherein, in the radially expanded state, the second end has an oval cross-sectional shape in a plane perpendicular to the longitudinal axis; the stent comprising first and second radiopaque markers, the radiopaque markers for determining a rotational orientation of the stent in the radially compact state; wherein the oval of the crosssection has a major axis and a minor axis, wherein the first radiopaque marker intersects a first point on the oval, wherein the second radiopaque marker intersects a second point on the oval, wherein the first point is symmetrical with the second point across the minor axis or the major axis; the method further comprising: a step of imaging the stent within the patient’s vasculature using an imaging device; a step of rotating the stent, in the radially compact state, until the position of the radiopaque markers under imaging indicates that, when the stent is transitioned to the radially expanded state, the major axis of the second end will be aligned along a lateral axis of the patient; and a step of transitioning the stent to the radially expanded state.

[0031] The stent may be a balloon-expanded stent, and the step of transitioning the stent to the radially expanded state may comprise inflating a balloon inside the stent in its radially compact state to transition the stent to the radially expanded state; or 253 766 t! 0 / v9 / rco the stent may be a self-expanding stent that automatically transitions when the stent is no longer within the catheter.

[0032] According to a fifth aspect, there is provided a method of implanting a stent system in an aorta, wherein the stent system is the system of the third aspect; the method comprising: advancing a distal end of a catheter through a patient’s vasculature, the catheter containing the second stent; placing the second stent in a position in which the second stent crosses over the common iliac arteries and in which the aperture faces towards the aorta; transitioning the second stent to its radially expanded state; inserting the first stent partially through the aperture; and transitioning the first stent to its radially expanded state, such that the second end of the first stent is located inferior of the aperture and the first end of the first stent is located superior to the aperture.

[0033] In the step of the advancing a distal end of a catheter through a patient’s vasculature, the catheter may additionally contain the first stent, wherein the second stent is located proximate to the distal end of the catheter, and the first stent is located proximal of the second stent; and wherein the step of inserting the first stent partially through the aperture may include advancing the catheter partially through the aperture while the catheter still contains the first stent.

[0034] Before the step of transitioning the first stent to its radially expanded state, the method may comprise a step of aligning one or more radiopaque markers of the first stent with one or more radiopaque markers of the second stent.

[0035] Brief Description of the Figures

[0036] Reference will now be made, by way of example only, to the accompanying drawings in which:

[0037] Figure 1 depicts a known stent implanted in an aorta;

[0038] Figure 2A depicts a stent having a flared end;

[0039] Figure 2B depicts a first cross section of the stent of Figure 2A;

[0040] Figure 2C depicts a second cross section of the stent of Figure 2A;

[0041] Figure 2D depicts the stent of Figure 2A implanted in an aorta;

[0042] Figure 3A depicts a cross section of a torso and the stent in its radially compact state;

[0043] Figure 3B depicts a cross section of a torso and the stent in its radially expanded state; 253 766 t! 0 / v9 / rco

[0044] Figures 4A and 4B depict the stent under imaging at different rotational orientations;

[0045] Figure 5A depicts another design of stent having a flared end;

[0046] Figure 5B depicts a cross section of the stent of Figure 5A;

[0047] Figure 6 depicts another placement of radiopaque markers on a stent;

[0048] Figure 7 depicts another placement of radiopaque markers on a stent;

[0049] Figure 8A depicts another placement of radiopaque markers on a stent;

[0050] Figures 8B-D depict the radiopaque markers of the stent of Figure 8A under imaging at different rotational orientations of the stent relative to an imaging axis;

[0051] Figure 9A depicts the wire scaffolding of a stent, the scaffolding incorporating radiopaque markers;

[0052] Figure 9B depicts the oval cross-sectional shape defined by the wire scaffolding;

[0053] Figure 9C depicts the oval cross-sectional shape defined by the wire scaffolding when a cover is provided over the wire scaffolding;

[0054] Figure 10A depicts a second stent implanted across the common iliac arteries;

[0055] Figures 10B and 10C depict different views of the stent of Figure 10A when outside the body;

[0056] Figure 11A depicts another design of second stent implanted across the common iliac arteries;

[0057] Figures 11 B and 11 C depict different views of the stent of Figure 11 A when outside the body;

[0058] Figures 11 D and 11 E depict another design of second stent;

[0059] Figure 12A depicts a system comprising the stent of Figure 2 coupled to the stent of Figure 10A;

[0060] Figure 12B depicts a system comprising the stent of Figure 2 coupled to the stent of Figure 11A;

[0061] Figure 13 depicts a catheter containing a first stent and a second stent, both in a radially compacted state;

[0062] Figure 14A depicts a design of first stent having a flared end; and

[0063] Figures 14B and 14C depict the stent of Figure 14A coupled to a second stent. 253 766 t! 0 / v9 / rco

[0064] Description

[0065] The terms “distal” and “proximal” used herein take their usual meanings in the art. That is, the “distal” refers to parts / regions located furthest from the care provider and “proximal” refers to parts / regions closest to the care provider. The terms “superior” and “inferior” used herein take their usual meanings in the art. That is, “superior” refers to the direction towards the patient’s head and “inferior” refers to the direction towards the patient’s feet. The term “lateral” takes its usual meaning in the art. That is, the patient’s lateral axis is the axis from the patient’s left to their right. The terms “anterior” and “posterior” take their usual meaning in the art. That is, “anterior” refers to the patient’s front side, and “posterior" refers to their back side.

[0066] Figure 1 depicts the aorta 100, aortoiliac bifurcation 102, the right common iliac artery 104, and the left common iliac artery 106. Regions of deposits 108a-c (e.g., calcium deposits) are depicted and may generally be referred to as “deposits 108”. These deposits can impede blood flow through the aorta and iliac arteries. To restore blood flow, a stent 110 has been implanted in the aorta 100 and this stent 110 extends partially into the aortoiliac bifurcation 102. The stent 100 is cylindrical and, in the depicted expanded state, it has a radius R that is constant along the length of the stent 110 from its superior end to its inferior end. The stent 100, in its expanded state, defines a central lumen 111 through which blood may flow. The expanded stent has sufficient structural rigidity to hold the deposits 108a-c aside and thus maintain a clear central lumen 111.

[0067] Note that Fig. 1 is rendered as if the viewer is face-to-face with the patient, and thus the iliac artery depicted on the left-hand side of Fig 1 (i.e., “left” from the viewer’s perspective) is on the patient’s right-hand side, and is thus the patient’s right common iliac artery. The superior direction (i.e., towards the patient’s head) is depicted on Figure 1 , as is the inferior direction (i.e. towards the patient’s feet). This orientation of the patient applies equally to all figures herein depicting the aorta, aortoiliac bifurcation etc., such as Figures 2D, 10A, 11 A, 12A, 12B etc.

[0068] As may be seen in Figure 1 , the stent 110 conforms fairly closely to the original shape (i.e., without deposits 108a-c) of the aorta at the stent’s superior end. The stent 110 does not conform so closely to the shape of the aorta / aortoiliac bifurcation at the stent’s inferior end, where the aorta expands in its lateral axis to 253 766 t! 0 / v9 / rco where it turns into the aortoiliac bifurcation. In this region, the aorta and the aortoiliac bifurcation are generally oval in cross section, wherein the cross section is taken in a plane perpendicular to the superior / inferior axis of the patient. The long axis of the oval is oriented along the patient’s lateral axis and the short axis of the oval is oriented along the patient’s anterior-posterior axis.

[0069] Figure 2A depicts a perspective view of a stent 10 in the radially-expanded state. The stent 10 has a first end 12 and a second end 14, and a wall 16 of the stent extends between the first and second ends 12,14. That is, the stent 10 may be said to extend between the first and second ends 12,14. In the expanded state, the wall 16 defines a central lumen 17 through which blood may flow. At the first end 12, the stent 10 has a circular cross section, defined by a radius r measured from a center O12. The second end 14 is a flared end. At the second end 14, the stent 10 has an oval cross section. In this example, the oval shape is defined by two radii, each extending from a centre point O14: a minor radius r1 , and a major radius r2. The major radius r2 is measured orthogonal to the minor radius r1 , and the major radius r2 is larger than the minor radius r1 , i.e., r2 > r1 . The major radius r2 is the largest radius of the oval shape and the minor radius r1 is the smallest radius of the oval shape.

[0070] A longitudinal axis X is defined extending between the first and second ends 12,14, and that intersects the radial center O12 of the first end and the radial center O14 of the second end. The aforementioned cross sections at the first end 12 and the second end 14 are each taken perpendicular to the longitudinal axis X.

[0071] The cross section of the stent 10 in the expanded state may transition smoothly from the first end 12 to the (flared) second end 14, e.g., as shown in Figure 2A. For example, the first end 12 may be circular in cross section. As one moves along the stent 10 towards the second end 14, the initially-circular cross section may first become slightly oval and then becomes moreso with an ever-increasing major radius towards the second end 14. The second end 14 may thus have the largest major radius r2 of any cross section taken between the first end 12 and second end 14. In some embodiments, the minor radius r1 is constant along the entire length of the stent 10, such that the minor radius r1 at the second end is equal to the radius r of the circular first end 14. As before, all cross sections are taken in planes perpendicular to the longitudinal axis. The skilled reader will appreciate 253 766 t! 0 / v9 / rco that, mathematically speaking, a cross section through a cylinder taken in a plane that is not perpendicular to the cylinder’s longitudinal axis (and also not parallel to the longitudinal axis), will be elliptical, but such (non-perpendicular) cross sections are not what is meant here.

[0072] In this manner, the stent 10 may be said to have a flared second end 14, i.e., where the second end 14 flares outward compared to more-cylindrical portions closer to the first end 12. The flared end may optionally help better anchor the stent 10 within the aorta or aortoiliac bifurcation compared to a purely cylindrical stent (e.g., the stent 110 depicted in Fig. 1 ), which may help to prevent migration of the stent 10 after implantation. This may also optionally allow for smoother blood flow in the region around the second end of the stent, such as less turbulence or fewer regions of low blood velocity where deposition of calcium may preferentially occur.

[0073] Stents, including stent 10, are typically made of a scaffold of one or more thin wires (or struts) such that, when expanded, stents look like a generally cylindrical net. For example, it is known that a single wire may be knitted into a tubular shape to form a stent. It is also known to braid wires to form a stent. It is also known to laser-cut sections out of a cylindrical tube to form a stent. In this example, the pieces of material that remain between cut-out sections may be considered to be wire(s) forming the scaffold of the stent.

[0074] These designs of the wire(s) mean that any given cross-section of the stent 10 will typically have spaces between regions of the wire material, i.e., the “holes” of the “net”, but nonetheless, the wire(s) still define a clearly-discernible cross sectional shape of the stent, such as a circular cross section or an oval cross section etc. A stent, including stent 10, may optionally have a cover over the outside of the wire scaffold. In such cases, the cover will take on the clearly-discernible cross- sectional shape defined by the scaffold. With such covered stents (also called “stengrafts”) the cover is in contact with the tissue of the aorta 100 and / or deposits 108 when the stent is implanted in a patient.

[0075] Figure 2B shows a cross-sectional view of the first end 12 of the stent 10 of Figure 2A. Figure 2C shows a cross-sectional view of the second end 14 of the stent 10 of Figure 2A. 253 766 t! 0 / v9 / rco

[0076] The radius r at the first end 12 may be the same as (i.e. , equal to) the minor radius r1 at the second end 14, or these two radii may be different. The minor radius r1 will typically be equal to or larger than the radius r at the first end 12.

[0077] In the stent 10 shown in Figures 2A-C, the oval cross section at the second end 14 is an ellipse. An ellipse has a major axis (Ma in Fig. 2C) and a minor axis (Mi in Fig. 2C) that is orthogonal to the major axis Ma. The minor axis Mi is an axis of symmetry of the ellipse. The major axis Ma is another axis of symmetry of the ellipse. The ellipse therefore has two axes of symmetry. Other oval shapes are envisaged, however, including oval shapes having only one axis of symmetry, such as an egg shape.

[0078] In healthy adults, the (unoccluded) aorta 100 in the region approaching the aortoiliac bifurcation will typically have a diameter in the range of 2.5 cm to 3.5 cm. Thus, the radius r at the first end 12 of the stent 10 in the expanded configuration may be typically in the range of 0.7 cm to 1.8 cm. However, a larger or a smaller radius r for the stent 10 may be required for other patients.

[0079] As the aorta 100 turns into the aortoiliac bifurcation 102, the aorta 100 expands in the lateral direction such that the aorta has a generally oval cross-sectional shape in this region. That is, the aorta 100 becomes wider in the patient’s lateral axis (left-right direction), compared to the anterior-posterior axis (i.e., front-back direction). In the region approaching and turning-into the aortoiliac bifurcation, the diameter in the lateral axis may increase by about 40% (compared to the original diameter) to a range of 3.5 cm to 5 cm, while the diameter in the anterior-posterior axis remains substantially constant (i.e., remains in the range 2.5 cm to 3.5 cm. Thus, the radius along the major axis of the second end of the stent 10 may be in the range 1.7 cm to 2.5 cm. The radius along the minor axis of the second end of the stent 10 may be in the range 0.7 cm to 1.8 cm, and the radius along the major axis is larger than the radius along the minor axis (e.g., by about 40%)

[0080] When the stent 10 is implanted in a patient, the oval shape of the second end 14 of the expanded stent 10 should be aligned with the oval shape of the aorta 100 in this region. Put another way, the major axis Ma of the stent 100 should be aligned along the lateral axis of the patient. The minor axis Mi of the oval cross section of the stent 10 is thereby aligned with the anterior-posterior axis of the patient. Figure 2D depicts the stent 10 implanted in a patient with the flared second end 14 253 766 t! 0 / v9 / rco located in the aortoiliac bifurcation 102. As may be seen by comparison with Figure 1 , the stent 10 of Figure 2D more-closely conforms to the shape of the aorta / bifurcation than the prior art cylindrical stent 110 shown in Figure 1 .

[0081] To facilitate correct alignment of the stent 10 relative the aorta 100, a first radiopaque marker 18 and second radiopaque marker 20 are provided on the stent 10. The first and second radiopaque markers 18,20 are arranged symmetrically either side of either the major axis or the minor axis of the stent 10. In the stent 10 shown in Figures 2A-D, the radiopaque markers 18,20 are arranged symmetrically either side of the major axis Ma and are arranged at the second end 14 of the stent 10. However, the radiopaque markers can take a variety of different shapes and arrangements on the stent 10. A number of different examples of these shapes and arrangements are discussed below.

[0082] Figure 3A depicts a cross section of a human torso 112 with the aorta 100 (not to scale). Some deposits 108a,b are depicted that are partially occluding the aorta 100. Other internal anatomical features are not shown, for improved clarity. The stent 10 is in its radially compact state in Figure 3A. When the stent 100 is in the radially compact state, it may have a different cross-sectional shape at various locations compared to stent 10 in its radially expanded state. For example, the stent 10 may be substantially cylindrical along its entire length in the radially compact state, and only achieve the aforementioned oval cross-sectional shape at its second end 14 when the stent 10 is transitioned into its radially expanded state.

[0083] During the implantation procedure, a radio-imaging device 114 is positioned outside the patient to locate the stent 10 within the patient. In the example shown in Figure 3A, the imaging device 114 is located in front of the patient and is imaging the patient along an imaging axis IA that is aligned with the patient’s anterior-posterior axis (i.e., from front to back) in this example. The cross section is taken in a plane that intersects the inferior end of the aorta 100 where the aorta has an oval cross-sectional shape. The radio-imaging device 114 is communicatively coupled to a display 116. This communicative coupling may be a wired connection or wireless connection, for example.

[0084] The following discussion will assume that the imaging axis IA is aligned with the patient’s anterior-posterior axis, and the up-down axis on the display 116 is oriented along the patient’s superior-inferior axis (i.e., head to toe). In this 253 766 t! 0 / v9 / rco arrangement, the major axis of the oval shape of the patient’s aorta 100 is in the left-to-right direction on the display 116. However, in some situations, it may be necessary to perform imaging along a different imaging axis. For example, the imaging may be done from the patient’s side, such that the imaging axis is aligned with the patient’s lateral axis. In such an arrangement, the minor axis of the oval shape of the patient’s aorta 100 will be in the left-to-right direction on the display. It should be borne in mind that a change of imaging axis will affect what relative orientation of the radiopaque markers 18,20 shown on the display 116 corresponds to the correct alignment of the stent 10 relative to the aorta 100.

[0085] In the orientation of the stent 10 relative to the imaging device 114 depicted in Figure 3A, the radiopaque markers 18,20 overlap with one another when viewed along the imaging axis IA that is aligned with the anterior-posterior axis of the patient. Thus, these two radiopaque markers appear as a single item (a single dot, in this instance) on the display 116.

[0086] Figure 3B depicts the cross section of the torso 112 once the stent 10 has been transitioned to its expanded state. The stent 10 compresses the deposits 108a,b back towards the wall of the aorta 100 and thus the stent 10 provides an enlarged flow path for blood through the central lumen of the stent 10, compared to the partially occluded aorta 100 depicted in Fig 3A. The stent 10 is has an oval cross- sectional shape in the depicted plane.

[0087] Figures 4A and 4B show the stent 10 at different rotational orientations relative to the imaging axis IA, compared to the orientation of Fig. 3A. Figure 4A shows the stent 10 at an orientation in which a line joining the two radiopaque markers 18,20 is perpendicular to the imaging axis IA. On the display 116 shown in Figure 4A, the radiopaque markers 18,20 thus appear as two dots separated relatively far apart. Figure 4B shows the stent at an orientation where the line joining the radiopaque markers 18,20 is oblique to the imaging axis IA. On the display 116 shown in Figure 4B, the radiopaque markers 18,20 thus appear as two dots that are closer together compared to the dots in Figure 4A. The separation of the radiopaque markers 18,20, as shown on the display 116, is greatest when the line joining the radiopaque markers 18,20 is perpendicular to the imaging axis IA, as shown in Figure 4A. 253 766 t! 0 / v9 / rco

[0088] In this manner, a person viewing the display 116 (e.g., a physician) can determine the rotational orientation of the stent 10 relative to the aorta 100 by viewing the radiopaque markers 18,20 on the display 116, and by knowing the imaging axis of the imaging device 114. When the radiopaque markers 18,20 appear furthest apart from one another on the display 116, the stent 10 is in a first orientation (e.g., as in Fig 4A). When the radiopaque markers 18,20 overlap and appear as a single marker on the display (e.g., as in Fig 3), the stent 10 is in a second orientation, orthogonal to the first orientation.

[0089] The placement of the radiopaque markers 18,20 on the stent 10 is predetermined. That is, a given stent 10 is produced with the radiopaque markers 18,20 in preselected positions that are symmetrically located across either the minor axis Mi or the major axis Ma of the oval cross section.

[0090] In Figures 2A-C, the radiopaque markers 18,20 are symmetrically disposed either side of the major axis Ma. When implanting the stent 10 into an aorta 100, the correct orientation is to have the major axis Ma of the second end 14 extend in the patient’s lateral direction. Thus, while the stent 10 is still in its radially-compact state, the user (e.g., physician) will adjust the orientation of the stent 10 until the radiopaque markers 18,20 overlap one another and appear as a single marker on the display, e.g., as shown in Figure 3A. This is because the imaging axis IA of the imaging device 114, in this example, extends in the anterior-posterior direction. Thus, when the radiopaque markers 18,20 are aligned with one another (i.e., overlap one another) along the imaging axis IA, the major axis Ma of the stent 10 will be oriented in the patient’s lateral direction once the stent 10 is expanded. The stent 10 is shown in the expanded state in Figure 3B.

[0091] In different examples, the radiopaque markers may be symmetrically disposed either side of the minor axis Mi. In this case, the user (e.g., physician) would rotate the stent 10 until the radiopaque markers 18,20 shown on the display 116 are maximally far apart, and then expand the stent 10. This would again ensure that the oval shape of the second end 14 of the stent 10 is correctly aligned with the original (i.e., unoccluded) oval shape of the aorta 100 in this region.

[0092] In other examples, not shown, the first end 12 of the stent 10 is not circular in cross section. For example, the first end 12 may have an oval cross section. For embodiments where an oval cross section is provided at the first end, this oval 253 766 t! 0 / v9 / rco cross section at the first end is preferably different from the oval cross section at the second end, and is smaller in at least one axis. However, an oval cross section at the first end may be the same as the oval cross section at the second end.

[0093] The radiopaque markers 18,20 may take a variety of different forms and be located at different points on the stent 10. In particular, the radiopaque markers 18,20 do not need to be located precisely at the second end 14 of the stent 10, but may be located at any common height along the longitudinal axis X. For example, the radiopaque markers 18,20 may both be located half-way along the stent 10, between the first and second ends 12,14, or may be located proximate or at the first end 10. The radiopaque markers 18,20 may be identical to each other, but this is not essential. Various examples of different locations and / or shapes and / or designs of radiopaque markers are shown in Figures 5A-9A. In Figures 5A-9A, the first radiopaque markers are labelled 18a-e; similarly, the second radiopaque markers are labelled 20a-e. Each of the radiopaque markers 18a-e of Figures 5-9 performs the same function as the first radiopaque marker 18 of Figures 2-4B, and each of the radiopaque markers 20a-e of Figures 5A-9 performs the same function as the second radiopaque marker 20 of Figures 2-4B.

[0094] Gold, platinum, and tantalum are examples of suitable materials for forming radiopaque markers, e.g., radiopaque markers 18,20. In some embodiments, the radiopaque markers may be attached to wire(s) of the stent via, e.g. microwelding.

[0095] Figure 5A depicts the radiopaque markers 18a, 20a arranged symmetrically across the minor axis Mi. The radiopaque markers 18a, 20 are located between the first end 12 and the second end 14 of the stent 10, at a common height. That is, measured along the longitudinal axis X, the first radiopaque marker 18a and the second radiopaque marker 14 are both located the same distance from center O12 of the cross-section of the first end 12. As the cross section of Figure 5B is taken looking towards the second end 14, the second end 14 is depicted in dashed lines in Figure 5B, from which the reader can discern the larger oval cross section at the second end 14.

[0096] Figure 6 depicts a cross section of the stent 10 taken at a location between the first and second ends 12,14. In this example, the radiopaque markers 18b, 20b are located symmetrically across the major axis Ma. However, unlike in Figure 2C, the 253 766 t! 0 / v9 / rco radiopaque markers 18b, 20b do not intersect the minor axis Mi. When the imaging axis IA is along the patient’s anterior-posterior axis, the radiopaque markers 18b, 20b will overlap one another when the stent 10 is in the correct orientation relative to the aorta 100, i.e. , such that the major axis Ma of the expanded stent 10 will be oriented along the patient’s lateral axis.

[0097] Figure 7 depicts a cross section of the stent 10 taken at a location between the first and second ends 12,14. In this example, the radiopaque markers 18c, 20c are located symmetrically across the minor axis Mi. However, unlike in Figure 5B, the radiopaque markers 18c, 20c of Figure 7 do not intersect the major axis Ma of the oval. When the imaging axis IA is along the patient’s anterior-posterior axis, the radiopaque markers 18b, 20b will be maximally far apart from one another when the stent 10 is in the correct orientation relative to the aorta 100, i.e. such that the major axis Ma of the expanded stent 10 will be oriented along the patient’s lateral axis.

[0098] In Figures 2A-7, the radiopaque markers 18,20 are depicted as dots on the stent 10. These may, for example, be pieces of radiopaque material affixed to wires that form the scaffold of the stent 10 (see e.g., Figure 9 for examples of the wires). Other shapes of radiopaque markers are envisaged, including, but not limited to, those depicted in Figure 8A-D and 9A.

[0099] Figure 8A depicts an example in which the first radiopaque marker 18d forms a generally vertically extending line, i.e., a line extending substantially parallel to the longitudinal axis X of the stent 10. The second radiopaque marker 20d is a generally horizontally extending line, i.e., extending around the circumference of the stent 10. As shown in Figures 8B-D, the radiopaque markers 18d,20d are on opposite sides of the stent 10 from one another. In this example, the radiopaque markers 18d,20d are symmetrically disposed across the major axis Ma. Figures 8B-C show different rotational orientations of the stent 10 relative to the imaging axis IA, and show how these radiopaque markers 18d,20d appear on the display 116.

[0100] In Figure 8B, a line joining the radiopaque markers 18d,20d is perpendicular to the imaging axis IA. The first radiopaque marker 18d appears as a vertical line and the second radiopaque marker 20d (which is being viewed largely end-on) appears as a dot on the display 116. 253 766 t! 0 / v9 / rco

[0101] Figure 8C shows a rotational orientation of the stent 10 in which a line joining the two markers 18d,20d is oblique to the imaging axis IA. The first radiopaque marker 18d still appears as a vertical line. The second radiopaque marker 20d now appears as a short horizontally-extending line.

[0102] In Figure 8D, the two radiopaque markers 18d,20d are aligned with one another along the imaging axis IA. The radiopaque markers 18d,20d now overlap to form a cross on the display 116.

[0103] When the radiopaque markers are formed as dots, larger radiopaque markers (i.e. , larger dots) may be more easily identifiable on the display 116. However, larger markers will also appear to overlap with one another at a greater range of orientations of the stent 10, and thus may allow for a less accurate determination of the orientation of the stent compared to stents with smaller markers. The crossshape formed by the markers 18d,20d may optionally provide the same benefits as for larger markers without the corresponding loss of accuracy in determining the rotational orientation of the stent 10, e.g. when the cross shape is regular (i.e. all arms of the cross have the same length) then the stent is in the correct orientation.

[0104] The skilled reader will appreciate that, in the example of Figures 8 and 9, only a portion of the first radiopaque marker 18d,e overlaps with only a portion of the second radiopaque marker 20d,e, when the markers are aligned along the imaging axis. That is, it is not essential that, for example, the second radiopaque marker 20 entirely obscures the first radiopaque marker 18 when the markers overlap along the imaging axis. It is sufficient for only a portion of each of the markers to overlap. Thus, it is sufficient if the first radiopaque marker 18 intersects a first point on the oval cross section and the second radiopaque marker 20 intersects a second point on the oval cross section, and the first and second points are symmetrically disposed either side of either the major axis or the minor axis.

[0105] Figure 9A shows the second end 14 of a stent 10 in which the wire 22 that makes up the stent 10 or stent scaffold are depicted. As mentioned previously, a stent may be made of multiple interconnected wires, or made from a single wire, kitted into the stent shape, or the wires may simply be sections of a cylinder that remain after laser cutting has been performed on the cylinder. 253 766 t! 0 / v9 / rco

[0106] The wire 22 may also be present in all of the previously discussed stent designs but is simply not depicted in earlier figures for clarity. In Figure 9A, two portions of the wire 22 are made from a radiopaque material, and other portions of the stent scaffold (i.e., other wire(s) 22) are made from non-radiopaque material or, at least, substantially-less-radiopaque material. The portion of the wire 22 between points c and d is made of a radiopaque material and forms the first radiopaque marker 18e. The portion of the wire 22 between points a and b is made of a radiopaque material and forms the second radiopaque marker 20e. Similar to the example depicted in Figures 8A-D, when these two radiopaque markers 18e,20e overlap with one another under imaging, they will form a cross shape on the display (e.g. display 116). In the example of Figure 9A, the cross shape will be approximately an “X” shape, whereas in the example of Figures 8A-D, the cross shape is approximately a “+” shape. Replacing portions of the scaffold wire 22 with radiopaque material may optionally allow for a smaller stent 10 in the collapsed state compared to stents in which the radiopaque material is added on to the stent, e.g., as dots affixed onto the wire 22 or onto a cover 24 over the wire 22 (see Figure 9C).

[0107] Figure 9B shows an example of a second end 14 of the stent 10 in which wire 22 that forms the stent 10 is depicted. The dashed line indicates the oval cross- sectional shape of the flared second end 14 of the stent 10. The wire 22 may be made of ninitol, for example, which is a metal alloy of nickel and titanium.

[0108] Figure 9C shows an example of a second end 14 of the stent 10 comprising a cover 24 that is attached to the outside of the stent wire 22. The cover 24 may be made of any compressible biocompatible material. In this example, the cover 24 closely or exactly follows the oval cross-sectional shape. A stent 10 having a cover 24 may also be called a “covered stent” or a “stentgraft”.

[0109] The stent 10 may be self-expanding (SX) or balloon-expanded (BX). Selfexpanding stents are designed to be springy and compressible into a radially compact state. They are typically held in their compact state by being inserted into the lumen of a catheter, wherein the walls of the catheter hold the SX stent in its compact state. When the catheter is removed from around the SX stent (or, equivalently, when the stent is pushed out of the end of the catheter), the resilience of the SX stent causes it to automatically transition to its radially 253 766 t! 0 / v9 / rco expanded state. Balloon expanded stents may remain in a radially compact state after being removed from a catheter. After the catheter is removed, a balloon located inside the BX stent is inflated and this balloon causes the BX stent to transition to its radially expanded state.

[0110] The following method may be used to implant the stent 10 in a patient. First, an access is formed in the patient, e.g., in the patient’s leg. A catheter containing the stent 10 in its radially compact state is advanced through the patient’s vasculature to the aorta 100 under imaging, e.g., using imaging device 114. With brief reference to Figure 13, this Figure shows a catheter 80 containing (among other items) the first stent 10. When the stent 10 is in the correct position in the aorta 100 along the superior-inferior axis of the patient, the user (e.g., physician) checks the rotational orientation of the stent 10 in the manner described hereinabove. That is, the physician identifies the two radiopaque markers 18,20 on the display 116 and rotates the catheter, and thereby rotates the stent 10, until the radiopaque markers 18,20 indicate that stent 10 is properly aligned with the aorta 100 such that, when the stent 10 is expanded, the major axis Ma of the flared second end 14 will be aligned with the major axis of the oval shape of the aorta 100 in this region. The stent 10 is then expanded by the user.

[0111] As above, the stent 10 may be self-expanding (SX), in which case, once the stent is in position, the catheter is retracted from around the stent 10 and the stent 10 expands. Alternatively, the stent 10 may be balloon-expanded (BX). In which case, when the stent 10 is no longer covered by the catheter, one or more balloons inside the stent 10 is inflated to expand the stent 10. The balloon (or balloons) may be configured such that, in the fully expanded state, part of the balloon forms an external surface that is substantially identical to the stent shape depicted in Figure 2, i.e. , the balloon may be wider and oval at one end and may be cylindrical at the other end. In this manner, the balloon may provide even loading on the stent 10 during transition to its expanded state, so that the stent 10 takes on the correct final shape and is not bent / deformed out of the desired final shape.

[0112] The catheter and any balloon(s) may then be removed from the patient.

[0113] The stent 10 discussed hereinabove may be used in conjunction with a second stent 40 that crosses over the right and left common iliac arteries 104,106. Figure 10A depicts this second stent 40. The second stent 40 may be for treating 253 766 t! 0 / v9 / rco aortoiliac occlusive disease caused, for example, by deposits 108d-f that have formed in the iliac vessels and in the aortoiliac bifurcation 102. The second stent 40 has a first end 42 that, when implanted in a patient, sits in the right common iliac artery 104 and a second end 44 that, when implanted in a patient, sits in the left common iliac artery 106. A wall 44 of the second stent 40 extends between the first end and the second end 42,44. As depicted in Figure 10B, the second stent 40 has an aperture 48 formed in the wall 46 at a location between the first and second ends 42,44. The wall 44 thus defines a central lumen for blood flow from the aperture 48 (i.e. blood coming from the aorta 100) into the right common iliac artery 104 and from the aperture 48 into the left common iliac artery 106. The central lumen of the second stent 40 may be generally cylindrical along its length and thus have a characteristic radius r40. This characteristic radius r40 may be the same as, or different to, any radius of the first stent 10 (e.g., radius r, radius r1 , radius r2). The characteristic radius r40 may be smaller than the radius r of the first end 12 of the first stent 10, due to the iliac arteries 102,104 having typically smaller diameters compared to the aorta 100. Alternatively, the second stent 40 may have a varying radius between the first and second ends. For example, the second stent may have a larger radius in a middle section that contains the aperture 48, and smaller radii at a first end section (which extends from the middle section to the first end 42) and at a second end section (which extends from the middle section to the second end 44).

[0114] In Figure 10B, the inside of the second stent 40 has been shaded with hashed lines to more clearly depict the aperture 48. The aperture 48 has an oval shape having a major axis Ma40 and a minor axis Mi40. The major axis Ma40 of the oval shape is aligned along with an axis extending from the first end 42 to the second end 44 of the second stent 40. As a result, when the second stent 40 is in position crossing over the common iliac arteries, the major axis of the oval is aligned with the patient’s lateral axis. That is, the long axis of the oval aperture 48 is aligned left-to-right across the patient, and thus the oval shape of the aperture 48 substantially matches the oval shape of the aortoiliac bifurcation 102.

[0115] One or more radiopaque markers 49a, b may be located around the rim of the aperture 48. These radiopaque markers 49a, b may optionally assist with orienting the second stent 40 during implantation, to ensure the aperture 48 faces in the superior direction, i.e., towards the aorta 100. 253 766 t! 0 / v9 / rco

[0116] Alternatively, the entire rim of the aperture 48 may be made from a radiopaque material. In this alternative, when the second stent 40 is in the correct orientation, the radiopaque rim will appear generally as a single line under imaging along the patient’s anterior-posterior axis, i.e., when imaging is being performed as discussed in detail hereinabove in relation to the first stent 10.

[0117] The second stent 40 may include further radiopaque markers (not shown) to assist in orienting the second stent 40 during implantation. For example, radiopaque markers may be provided on or proximal to the first and second ends 42,44.

[0118] The second stent 40 may be covered or uncovered. The cover may, for example, be made from ePTFE (expanded PTFE).

[0119] As before, stents, including the second stent 40, may be formed of a scaffold of thin wire such that the overall stent has, in the expanded state, the appearance of a cylindrical ‘net’. A net has holes between the material forming the net (i.e., the wire of the scaffold defines holes therebetween). However, these holes will be far smaller than the aperture 48, such that in the expanded state, the aperture 48 can be clearly discerned as distinct from the holes of the ‘net’. In a covered second stent 40, the aperture 48 is clearly identifiable as an aperture in the cover, as well as in the scaffold. The aperture 48 may be more than twice the size of any of the aforesaid holes formed by the wire 22. In other examples, the aperture may be greater than 4x, 6x, or 10x the size of any of the aforesaid holes formed by the wire 22.

[0120] Figures 11A-C depict three views of another design of second stent 40 for crossing over the right and left common iliac arteries 104,106, which is the same as the second stent 40 of Figures 10A-C except for the addition of a chimney portion 50. The aperture 48 is formed in the chimney portion 50. When implanted (see Fig 11 A), the chimney portion 50 of the stent 40 extends upwards towards the aorta 100. One or more radiopaque markers 49a, b may be located around the rim of the aperture 48. Alternatively, the entire rim of the aperture 48 may be made from a radiopaque material.

[0121] As shown in Figure 11 D, a plurality of wires 52 may initially partially obscure the aperture 48. This may be the case while the second stent 40 is in its radially compact state. Once the second stent 40 is expanded, the wires 52 are pushed 253 766 t! 0 / v9 / rco upwards (e.g., by a catheter delivering the first stent 10) towards the aorta 100. These wires 52 then form all or part of the chimney portion 50. One or more of the wires 52 may optionally be made of radiopaque material, to provide the radiopaque markers for initially aligning the second stent and then, later, for aligning first stent 10 relative to the second stent 40. Alternatively or additionally, tungsten dots may be embedded in the chimney portion or around the aperture, to provide radiopaque marking. When the second stent 40 is covered, the wires 52 may be left uncovered or the wires 52 may also be covered.

[0122] The various designs of second stent 40 described hereinabove in relation to Figures 10A-11 D may be used in combination with the stent 10 described hereinabove in relation to any of Figures 2-9, and this system is depicted in Figure 12. That is, Figure 12 depicts a system 60 comprising the stent 10 (which may be called an aortic stent, and may be any of the examples of the stent 10 described hereinabove in relation to Figures 2-9) and the second stent 40 (which may be called an iliac crossover stent, and may be any of the examples of the second stent 40 described herein above in relation to Figures 10A to 11 E.

[0123] Figure 12A and 12B both depict a system 60 comprising an (aortic) stent 10 and an (iliac) second stent 40. In Figure 12A, the iliac stent 40 is the design shown in Figures 10A-C. The flared second end 14 of the aortic stent 10 sits inside the iliac stent 40. The wall 16 of the aortic stent 14 then extends upwards, through the aperture 48, and into the aorta 100. The overall system 60 thus provides two interlocking stents 10,40 that generally form the shape of an inverted “Y”. The second end 14 of the aortic stent 10 flares outwards, in the radially expanded state, and, at its greatest extent, is larger than the aperture 48 such that the aortic stent 10 cannot pull out from the iliac stent 40. The system 60 may be used in the “CERAB” (Covered Endovascular Reconstruction of the Aortoiliac Bifurcation) surgical procedure.

[0124] In Figure 12B, the iliac stent 40 is the design shown in Figures 11A-C, i.e., the second stent 40 with the chimney portion 50. Again, the flared second end 14 of the aortic stent 10 is located inside the iliac stent 40, and the wall 16 of the aortic stent extends upwards, through the chimney portion 50 and the through the aperture 48 and into the aorta 100. 253 766 t! 0 / v9 / rco

[0125] The chimney portion 50 may be shaped such that, when the iliac stent 40 is in the expanded state, the chimney portion 50 conforms in three dimensions to the shape of the flared second end 14 of the aortic stent 10. This may provide improved coupling between the aortic stent 10 and iliac stent 40 and may allow for smoother fluid flow through the stents 10,40. The chimney portion 50 may be sized such that only the chimney portion 50 of the second stent 40 contacts the flared second end 14 of the (aortic) stent 10. In one example, the entire outer surface system 60 may have a size and shape substantially identical to the original (i.e., unoccluded) aorta, aortoiliac bifurcation, and common iliac arteries of the patient. In this example, the fluid flow path defined by the inner surfaces of the stents 10,40 may be highly similar to the original (i.e., unoccluded) aorta, aortoiliac bifurcation, and common iliac arteries of the patient. In particular, the flared second end 14 may be designed to closely match the contour of the second stent 40 at and around the aperture 48, such that the two stents 10,40 together provide a smooth flow path from the aorta 100 to the iliac arteries 102,104.

[0126] The one or more radiopaque markers 49a, b may assist in aligning the (aortic) stent 10 with the second stent 40. For example, the radiopaque markers 49a, b and the radiopaque markers 18,20 may be positioned such that markers on the first stent 10 overlap with markers on the second stent 40, when viewed along the imaging axis, when the two stents 10,40 are properly aligned with one another, such that the first stent 10 may be transitioned to its radially expanded state and engage with the second stent 40. Alternatively, the first stent 10 may have additional radiopaque markers (not shown) for aligning the first stent 10 with the second stent 40.

[0127] The first stent 10 and second stent 40 may be placed in the catheter 80 in a predetermined orientation relative to each other. This orientation may be such that the flared second end 14 of the first stent 10 (when in its expanded state) is correctly oriented relative to the aperture 48 of the second stent 40. In this manner, once the second stent 40 has been aligned such that its aperture 48 faces into the aorta 100 and the second stent has been transitioned to its expanded state, the first stent 10 is already in the correct orientation relative to the aperture 48, such that when the catheter 80 is advanced partially through the aperture 48 to deploy the first stent 10, the oval cross sectional shape of the flared second end 14 (that the first stent will have when it is in the radially expanded state) is already aligned with the oval shape of the aperture 48. That is, with this 253 766 t! 0 / v9 / rco design, optionally no further adjustment of the rotational alignment of the first stent 10 may be required after the second stent 40 has been correctly oriented.

[0128] The second stent 40 may have an outer diameter of 10 French or less, i.e., an outer diameter of 3.3 mm or less, in the radially compact state. In the radially expanded state, the second stent 40 may have an outer diameter of 12 mm, for example. The second stent 40 may be 40 mm long, or may be 100 mm long, or may be longer or shorter as required.

[0129] Figure 13 depicts a catheter 80 that contains the iliac stent 40 in its radially compact state and the aortic stent 10 in its radially compact state (not to scale). As before, when the first (aortic) stent 10 is in its radially compact state, the second end 14 may be substantially cylindrical, as shown, and the first stent 10 may only obtain the flared second end 14 having an oval cross section when the stent 10 is transitioned to its radially expanded state. The catheter 80 has a distal end 62 and a proximal end 64. The catheter 80 may be guided through the vasculature by a guidewire 70. The aortic stent 10 is located distal of the iliac stent 40 within the catheter 80, such that, during the implantation procedure, the iliac stent 40 is the first to be implanted. After the iliac stent 40 has been transitioned to its radially expanded state, the first (aortic) stent 10 may, still in its radially compact state, be advanced through the aperture 48 until the first end 12 sits within the aorta 100 and the second end sits inside the aperture 48 (i.e. sits inside the second stent 40), and then the aortic stent 10 may be transitioned to its radially expanded state.

[0130] The first stent 10 may be arranged within the catheter 80 such that its first end 12 is distal of its second end 12. That is, the first end 12 of the first stent 10 may be generally adjacent to one of the ends 42,44 of the second stent 40. In this manner, when the first stent 10 is moved out from the distal end of the catheter 80, the first end 12 comes out first, before the second end 14 comes out.

[0131] The following method may be used to implant the system 60 in a patient. An access is formed, for example, in the patient’s leg. A guidewire 70 is inserted and guided through the vasculature to cross over from one iliac artery to the other iliac artery.

[0132] The catheter 80 is advanced along the guidewire 70 to crossover the common iliac arteries 102,104. The user (e.g. physician) may use radiopaque markers 49a, b on 253 766 t! 0 / v9 / rco the second stent 40, if present, to check the orientation of the stent 40 before it is expanded. When the second stent 40 has the correct orientation and correct position, it is transitioned to its expanded state such that its first end 42 sits within one of the common iliac arteries, the second end 44 sits within the other of the common iliac arteries, and the aperture 48 faces towards the aorta 100.

[0133] The second stent 40 may be self-expanding (SX) or balloon-expanded (BX). Once the second stent 40 is implanted, the guidewire 70 may be retracted slightly and then advanced through the aperture 48 towards and into the aorta 100. The catheter 80 may then be immediately advanced along the guidewire 70, through the lumen of the now-expanded second stent, and up through the aperture 48. In examples having wires 52 across the aperture, the catheter 80 may push the wires 52 up into the aorta 100 as it advances through the aperture 48. The first (aortic) stent 10 is then placed in its correct position relative to the aorta 100 and second stent 40. The rotational orientation of the first stent 10 may be checked using markers 18,20 as described previously, and then the first stent 10 is transitioned to its radially expanded state, such that the flared second end 14 of the expanded first stent 10 is aligned with and engages with the aperture 48 / second stent 40 such that the two stents 10,40 cannot be pulled apart without deformation or damage to one or both stents 10,40.

[0134] In an alternative, not shown, the aortic stent 10 may be stored within a second, different catheter. In this case, the first catheter 80 is first removed from the patient and the second catheter is advanced along the guidewire 70 until it extends through the aperture 48. Once the second catheter is in place extending through the aperture, the user (e.g., physician) checks the rotational orientation of the stent 10 using the radiopaque markers 18,20 in the manner described hereinabove. Once the rotational orientation is correct relative to the aorta 100, the (aortic) stent 10 is expanded, such that its second end 14 interlocks with the second stent 40. The second catheter and guidewire 70 may then be removed from the patient.

[0135] Figure 14A depicts a first stent 10 having a flared second end 14, in the manner described hereinabove. The wire 22 forming the scaffold is visible. A portion of the wire 22 is formed of radiopaque material to form the first radiopaque marker 18. Figure 14B depicts the first stent 10 connected to the second stent 40. In this example, wires 52 that previously partially covered the aperture 48 have been pushed upwards during the insertion of the first stent 10 (and catheter) through the 253 766 t! 0 / v9 / rco aperture 48. Figure 14C shows the first stent 10 connected to a different second stent 40 having a chimney portion 50.

Claims

253 766 t! 0 / v9 / rcoCLAIMS:1 . A stent for an aorta, the stent having a longitudinal axis defined between a first end and a second end of the stent, the stent being transitionable from a radially compact state to a radially expanded state; wherein, in the radially expanded state, the second end has an oval cross- sectional shape in a plane perpendicular to the longitudinal axis; the stent comprising first and second radiopaque markers, the radiopaque markers for determining a rotational orientation of the stent in the radially compact state; wherein the oval of the cross-section has a major axis and a minor axis, wherein the first radiopaque marker intersects a first point on the oval, wherein the second radiopaque marker intersects a second point on the oval, wherein the first point is symmetrical with the second point across the minor axis or the major axis.

2. The stent according to claim 1 , wherein the first point is symmetrical with the second point across the major axis, and wherein the first point intersects the minor axis and the second point intersects the minor axis.

3. The stent according to claim 1 , wherein the first point is symmetrical with the second point across the major axis, and wherein the first point does not intersect the minor axis and the second point does not intersect the minor axis.

4. The stent according to claim 1 , wherein the first point is symmetrical with the second point across the minor axis, and wherein the first point intersects the major axis and the second point intersects the major axis.

5. The stent according to claim 1 , wherein the first point is symmetrical with the second point across the minor axis, and wherein the first point does not intersect the major axis and the second point does not intersect the major axis.

6. The stent according to any preceding claim, wherein the first point and second point are located proximate to the second end or at the second end.

7. The stent according to any of claims 1-5, wherein the first point and the second point are located between the first end and the second end.253 766 t! 0 / v9 / rco8. The stent according to any preceding claim, wherein the first radiopaque marker comprises a first line extending substantially along the longitudinal axis, and wherein the second radiopaque marker comprises a second line extending substantially circumferentially around the stent.

9. The stent according to any preceding claim, wherein the stent comprises one or more wires forming a scaffold, and wherein a first portion of the one or more wires is made of a radiopaque material and forms the first radiopaque marker, and wherein a second portion of the one or more wires is made of a radiopaque material and forms the second radiopaque marker, wherein other portions of the one or more wires are less radiopaque than either the first or second radiopaque markers.

10. The stent according to any preceding claim, wherein the stent comprises one or more wires forming a scaffold, and comprises a cover extending at least partially over the scaffold.11 . A stent system comprising: a first stent that is the stent according to any preceding claim, and a second stent that is transitionable between a radially compact state and a radially expanded state; the second stent comprising a wall extending between a first end of the second stent and a second end of the second stent, wherein an aperture is formed in the wall between the first and second ends of the second stent; wherein, the first stent is configured to couple to the second stent, and when the first stent and second stent are each in the expanded state, the oval cross section of the second end of the first stent is larger than the aperture.

12. The stent system according to claim 11 , wherein, when both the first stent and second stent are in their respective expanded states, the second end of the first stent is larger than the aperture such that the first stent cannot pull out of the second stent without deforming one or both of the stents.

13. The stent system according to claim 11 or 12, wherein the aperture is oval shaped and wherein the oval shape of the aperture conforms to an outer surface of the first stent at a predetermined height along the longitudinal axis of the first stent.253 766 t! 0 / v9 / rco14. The stent system according to any of claims 11 to 13, wherein the second stent comprises a chimney portion and the aperture is formed at an end of the chimney portion; and optionally wherein the first stent solely contacts the second stent solely at the chimney portion.

15. The stent system according to any of claims 11 to 14, wherein the first stent is a covered stent and / or wherein the second stent is a covered stent.

16. A catheter containing the stent system of any of claims 11 to 15, wherein the catheter has a distal end, wherein the first sent and second stent are each in their radially compact state, and wherein the second stent is located proximate to the distal end, and wherein the first stent is located proximal of the second stent.

17. A method of implanting a stent in an aorta, the method comprising: a step of advancing a catheter containing a stent through a patient’s vasculature; wherein the stent the stent has a longitudinal axis defined between a first end and a second end of the stent, the stent being transitionable from a radially compact state to a radially expanded state; wherein, in the radially expanded state, the second end has an oval cross- sectional shape in a plane perpendicular to the longitudinal axis; the stent comprising first and second radiopaque markers, the radiopaque markers for determining a rotational orientation of the stent in the radially compact state; wherein the oval of the cross-section has a major axis and a minor axis, wherein the first radiopaque marker intersects a first point on the oval, wherein the second radiopaque marker intersects a second point on the oval, wherein the first point is symmetrical with the second point across the minor axis or the major axis; the method further comprising: a step of imaging the stent within the patient’s vasculature using an imaging device; a step of rotating the stent, in the radially compact state, until the position of the radiopaque markers under imaging indicates that, when the stent is transitioned to the radially expanded state, the major axis of the second end will be aligned along a lateral axis of the patient; and a step of transitioning the stent to the radially expanded state.253 766 t! 0 / v9 / rco18. The method according to claim 17, wherein the stent is a balloon-expanded stent, and the step of transitioning the stent to the radially expanded state comprises inflating a balloon inside the stent in its radially compact state to transition the stent to the radially expanded state; or wherein the stent is a self-expanding stent that automatically transitions when the stent is no longer within the catheter.

19. A method of implanting a stent system in an aorta, wherein the stent system is the system of any of claims 11-15; the method comprising: advancing a distal end of a catheter through a patient’s vasculature, the catheter containing the second stent; placing the second stent in a position in which the second stent crosses over the common iliac arteries and in which the aperture faces towards the aorta; transitioning the second stent to its radially expanded state; inserting the first stent partially through the aperture; and transitioning the first stent to its radially expanded state, such that the second end of the first stent is located inferior of the aperture and the first end of the first stent is located superior to the aperture.

20. The method according to claim 19, wherein in the step of the advancing a distal end of a catheter through a patient’s vasculature, the catheter additionally contains the first stent, wherein the second stent is located proximate to the distal end of the catheter, and the first stent is located proximal of the second stent; and wherein the step of inserting the first stent partially through the aperture includes advancing the catheter partially through the aperture while the catheter still contains the first stent.21 . The method according to claim 19 or 20, wherein, before the step of transitioning the first stent to its radially expanded state, the method comprises a step of aligning one or more radiopaque markers of the first stent with one or more radiopaque markers of the second stent.

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