阅读说明：本技术 用于将自膨胀支架输送到静脉窦的方法和系统 (method and system for delivering self-expanding stents to the venous sinus ) 是由 杰弗里·P·卡利斯特 于 2018-03-08 设计创作，主要内容包括：一种支架输送系统,包括：从系统的近端延伸入在远端处的输送末端中的轴。轴包括线圈和支架床。支架装载到支架床上,并且在其远端处具有第一部分,该第一部分具有比在支架的近端处的第二部分更大的柔性。护套可在支架床上在预展开位置和展开位置之间移动。护套包括在护套远端处的柔性段、邻近柔性段的半柔性段和邻近半柔性段的刚性段。输送末端比支架床、支架的第一部分和护套的柔性段的组合更柔性,该组合比支架床、支架的第二部分和护套的柔性段的组合更柔性。(A stent delivery system comprising: a shaft extending from the proximal end of the system into the delivery tip at the distal end. The shaft includes a coil and a stent bed. The stent is loaded onto the stent bed and has a first portion at its distal end that has greater flexibility than a second portion at the proximal end of the stent. The sheath is movable on the stent bed between a pre-deployment position and a deployed position. The sheath includes a flexible section at a distal end of the sheath, a semi-flexible section adjacent the flexible section, and a rigid section adjacent the semi-flexible section. The delivery tip is more flexible than the combination of the stent bed, the first portion of the stent, and the flexible section of the sheath, which is more flexible than the combination of the stent bed, the second portion of the stent, and the flexible section of the sheath.)

1. A stent delivery system comprising:

A delivery handle at a proximal end of the stent delivery system;

A catheter hub;

A delivery tip at a distal end of the stent delivery system, wherein the delivery tip comprises a distal tip end and a proximal tip end, and wherein the delivery tip has a first flexibility;

A shaft extending from the delivery handle through the catheter hub and into the delivery tip, wherein the shaft comprises a coil having a coil distal end and a coil proximal end and a stent bed between the coil distal end and the tip proximal end;

A stent loaded onto the stent bed, wherein the stent comprises a stent distal end, a stent proximal end, and a cylinder between the stent distal end and the stent proximal end, and wherein a first portion of the cylinder at the stent distal end has greater flexibility than a second portion of the cylinder at the stent proximal end; and

A sheath coupled to the catheter hub and movable over the stent bed between a pre-deployed position and a deployed position, wherein the sheath extends over the stent bed if in the pre-deployed position, wherein the sheath is pulled back from the stent bed if in the deployed position, wherein the stent is compressed by the sheath over the stent bed if in the pre-deployed position, wherein the stent is expanded if in the deployed position the sheath is pulled back from the stent bed, wherein the sheath comprises a sheath distal end and a sheath proximal end, and wherein the sheath comprises a flexible segment at the sheath distal end, a semi-flexible segment adjacent the flexible segment, and a rigid segment adjacent the semi-flexible segment,

Wherein a combination of the stent bed, the first portion of the stent cylinder, and the flexible section of the sheath has a second flexibility less than the first flexibility, and

Wherein a combination of the stent bed, the second portion of the stent cylinder, and the flexible section of the sheath has a third flexibility that is less than the second flexibility.

2. The system of claim 1, wherein the coil comprises a loosely wound region at the coil distal end having greater flexibility than a tightly wound region of the coil at the coil proximal end.

3. The system of claim 2, wherein a combination of the loosely wound region of the coil and the semi-flexible section of the sheath has a fourth flexibility that is less than the third flexibility.

4. The system of claim 3, wherein a combination of the tightly wound region of the coil and the semi-flexible section of the sheath has a fifth flexibility that is less than the fourth flexibility.

5. The system of claim 4, wherein a combination of the tightly wound region of the coil and the rigid section of the sheath has a sixth flexibility that is less than the fifth flexibility.

6. The system of claim 5, wherein the shaft is adjacent to the coil and has a seventh flexibility less than the sixth flexibility in combination with the rigid section of the sheath at the coil proximal end.

7. The system of claim 1, wherein one or more of the delivery tip and the sheath are made of a medical grade polymer.

8. The system of claim 1, wherein the stent bed is a thin walled tube with constant stiffness.

9. The system of claim 1, wherein the delivery tip has a durometer of about 35.

10. the system of claim 1, wherein there is one or more of:

The flexible section of the sheath has a durometer of about 35,

The semi-flexible section of the sheath has a durometer of about 55, an

The rigid section of the sheath has a hardness of about 72.

11. A stent, comprising:

a distal end having a first diameter;

A proximal end having a second diameter greater than the first diameter; and

A cylinder between the distal end and the proximal end, the cylinder comprising circumferential strut segments and longitudinal connecting members, each circumferential strut segment comprising strut members arranged in a pattern, and each circumferential strut segment connected to at least one other circumferential strut segment by a portion of the longitudinal connecting members,

Wherein a first plurality of circumferential strut segments at a distal end of the stent has greater flexibility than a second plurality of circumferential strut segments at a proximal end of the stent.

12. the stent of claim 11, wherein the first plurality of circumferential strut segments at the distal end of the stent have a lower radially outward expansion strength than the second plurality of circumferential strut segments at the proximal end of the stent.

13. the stent of claim 11, wherein at least a portion of the cylinder is conical.

14. The stent according to claim 11 wherein the longitudinal connecting members are arranged in an open cell design.

15. The stent of claim 11, wherein the cylinder is made of nickel titanium.

16. The stent of claim 11, wherein the cylinder is 6 to 9 centimeters in length.

17. the stent of claim 11, wherein the pattern of strut members is a zigzag pattern having peaks and valleys.

18. The stent of claim 17, wherein the longitudinal connecting members are arranged in a periodic peak-to-valley connection scheme.

19. The stent according to claim 11 wherein a first width of one or both of the strut members and the longitudinal connecting members of the first plurality of circumferential strut segments at a distal end of the stent is less than a second width of one or both of the strut members and the longitudinal connecting members of the second plurality of circumferential strut segments at a proximal end of the stent.

20. The stent according to claim 11 wherein the first plurality of circumferential strut segments at the distal end of the stent is 8 circumferential strut segments and the second plurality of circumferential strut segments at the proximal end of the stent is 14 circumferential strut segments.

Technical Field

certain embodiments relate to stents and systems and methods for delivering stents. More particularly, certain embodiments relate to a method and system for treating stenosis or collapse in the venous sinus by delivering a self-expanding stent. In various embodiments, a self-expanding stent includes a proximal end having a first radially outward expansion strength (RES) greater than a second RES at a distal end of the stent. In one exemplary embodiment, the proximal end of the stent has a larger diameter than the diameter at the distal end of the stent. In certain embodiments, the stent delivery system and/or stent increases in flexibility from the proximal end to the distal end of the system and/or stent.

Background

When the blood leaving the brain slows due to a restriction in the venous sinus, it causes an increase in distal blood pressure, which can translate into an increase in cerebral fluid pressure. Patients experiencing increased intracranial pressure (ICP), in which the cerebrospinal fluid (CSF) pressure in the skull has increased, may suffer from headache, loss of vision, and/or tinnitus, among others. The preferred method for treating collapse and/or stenosis in the sigmoid and/or transverse sinuses is drug and/or use of shunts (shunt) to relieve CSF fluid pressure. However, the use of drugs or shunts is not ideal as both are temporary solutions, each with associated risks.

More recently, a new procedure has been performed which involves placing a stent in the venous sinus system of a patient to improve collapse and/or stenosis in the sigmoid and/or transverse sinuses and restore improved blood flow out of the brain. The stents used in the new procedure are generally the same stents used in the procedure for other parts of the body, such as the carotid artery. However, the venous sinus structure is not like any vein or artery that is the rest of the body. In contrast, the venous sinus is a void created at the dural junction and forms a cavity (i.e., sinus) primarily along the interior of the skull. The dura mater is not lined with smooth muscle cells and is inelastic when compared to veins and arteries.

Fig. 1 shows an exemplary sinus venosus system with a well-defined stent region. The venous sinus system includes a venous passageway found between the periosteal layer and the meningeal layer of the dura mater of the brain. The venous sinus system receives blood from the internal and external veins of the brain, receives CSF from the subarachnoid space via arachnoid granules, and empties primarily into the internal jugular vein. As shown in FIG. 1, the venous sinus system includes the transverse sinus, sigmoid sinus, and sigmoid. The sigmoid sinus integrates into the jugular vein at the sigmoid junction. Fig. 1 also identifies exemplary stent regions for placement of stents to treat collapse and/or stenosis in the sigmoid sinus and/or the transverse sinus.

Existing stent delivery systems and stents have several deficiencies for delivering stents to the sinus venosus. For example, existing stents and systems may not be able or difficult to navigate through a curved sigmoid knot to place the stent in the region of the stent.

As another example, the properties of existing stents may be undesirable for placement in the venous sinus. Typical carotid stents may be 4-6cm long. However, after placement of the carotid stent in the venous sinus, a portion of the transverse sinus may collapse, particularly the portion distal to the stent. If a stent is placed at the junction of the sigmoid sinus and the transverse sinus and is not long enough to support most or all of the transverse sinus, collapse of a portion of the transverse sinus may occur. Additionally, if there is collapse and/or stenosis at multiple locations in the sigmoid sinus and/or the transverse sinus, multiple carotid stents may be required. Also, stents of inappropriate length may be improperly positioned at a bend in the sigmoid sinus to block future access to the sinus (e.g., stent occlusion). For example, a stent that terminates within a bend rather than being positioned through the bend may occlude a portion or the entire sinus cavity at the bend.

Furthermore, existing stents typically have a set diameter. However, the medial and distal regions of the sigmoid sinus have, on average, a larger diameter (e.g., about 10-12mm) than the distal portion of the transverse sinus (e.g., about 6-9 mm). Thus, existing scaffold diameters located in both the sigmoid and transverse sinuses may not be sufficient for at least one sinus. For example, if the stent is too small for the vessel, a portion of the stent may remain hanging or free floating in the vessel, which may prevent proper growth of endothelial tissue on the stent struts. As another example, if a stent is too large for a vessel, various problems may arise because the radial outward expansion strength (RES) of a typical stent may be too strong for use in the venous sinus. In particular, stents for placement in large vessels (e.g., carotid, femoral, or venous, etc.) may have a high RES required to treat occlusions, atherosclerotic plaques, and calcification of lesions, and/or may withstand external forces capable of pushing into the stent. This high RES, coupled with a stent size that is too large for the vessel, creates the problem of the tissue in contact with the stent struts dying due to the strong outward pressure exerted on the tissue. Another problem with high RES when the stent is too large for the vessel is that the stent may push through the vessel wall and show up outside the vessel.

Existing stent designs may also have a substantial number of strut members. However, the venous sinus structure includes many venules leading from the brain. Thus, the number of strut members of a typical stent increases the chance that one strut may block or partially inhibit venous inflow from the brain via a vein.

Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.

Disclosure of Invention

Enhanced navigation of a stent delivery system for placement of a stent is provided by increasing the flexibility of the stent delivery system and/or the stent from the proximal end toward the distal end of the system and/or stent, substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims.

These and other advantages, aspects, and novel features of the present invention, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings.

Drawings

Fig. 1 illustrates an exemplary sinus venosus system with a well-defined scaffolding area, in accordance with various embodiments.

Fig. 2 illustrates an exemplary stent including a distal end and a proximal end, the distal end having greater flexibility than the proximal end, according to various embodiments.

fig. 3 illustrates an exemplary strut member of the exemplary stent of fig. 2, according to various embodiments.

Fig. 4 illustrates an exemplary profile of the exemplary stent 100 of fig. 2 having a distal end with a smaller diameter than a proximal end, according to various embodiments.

Fig. 5 illustrates an exemplary stent delivery system according to various embodiments.

Fig. 6 illustrates a detailed view of a portion of the exemplary stent delivery system of fig. 5, in accordance with various embodiments.

Fig. 7 illustrates a detailed view of the interior of the stent delivery system of fig. 5, according to various embodiments.

Fig. 8 illustrates a detailed view of the exterior of the stent delivery system of fig. 5, according to various embodiments.

Fig. 9 illustrates an exploded cross-sectional view of the interior of a stent delivery system, the stent, and the exterior of the stent delivery system, wherein the increased flexibility of the stent delivery system as the stent progresses from the proximal end toward the distal end of the system and stent is illustrated by a plot to an exemplary flexibility diagram, in accordance with various embodiments.

Fig. 10 is a flow diagram illustrating exemplary steps that may be used to provide enhanced navigation of a stent delivery system for placement of a stent, according to various embodiments.

Detailed Description

certain embodiments may provide enhanced navigation of a stent delivery system for placement of a stent by increasing the flexibility of the stent delivery system and/or the stent from the proximal end toward the distal end of the system and/or stent. Various embodiments provide a self-expanding stent including a proximal end having a first radially outward expansion strength (RES) greater than a second RES at a distal end of the stent. In one exemplary embodiment, the proximal end of the stent includes a diameter that is larger than the diameter at the distal end of the stent. In certain embodiments, the stent delivery system may be configured to treat a stenosis or collapse in the venous sinus by delivering a self-expanding stent.

The foregoing summary, as well as the following detailed description of certain embodiments, will be better understood when read in conjunction with the appended drawings. It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings. It is also to be understood that these embodiments may be combined, or that other embodiments may be utilized and structural changes may be made without departing from the scope of the various embodiments. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural said elements or steps, unless such exclusion is explicitly recited. Furthermore, references to "one embodiment" are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, unless explicitly mentioned to the contrary, embodiments "comprising" or "having" one or more elements having a particular property may include additional elements not having that property. As referred to herein, the terms "proximal" and "distal" are with respect to the delivery handle 210 of the stent delivery system 200 (also referred to as a catheter). For example, the distal ends 104, 204 of the stent 100 and catheter 200 are the ends that are first inserted into a patient's body lumen, while the proximal ends 102, 204 are opposite the distal ends 104, 204.

Fig. 2 illustrates an exemplary stent 100 according to various embodiments, which includes a distal end 104 and a proximal end 102, the distal end 104 having greater flexibility than the proximal end 102. Fig. 3 illustrates an exemplary strut member 112 of the exemplary stent 100 of fig. 2, according to various embodiments. Fig. 4 illustrates an exemplary profile of the exemplary stent 100 of fig. 2, the stent 100 having a distal end with a smaller diameter than a proximal end, according to various embodiments. Although fig. 2 and 3 may illustrate the stent 100 in a plan view, the top end of the stent 100 will be connected with the bottom end to form a cylindrically-shaped stent 100. Referring to fig. 2-4, self-expanding cylindrical stent 100 includes a distal end 104, a proximal end 102, and a plurality of circumferential strut segments 110. The strut section 110 may include strut members 112 and longitudinal connecting members 118. The strut members 112 can be arranged in a pattern, such as a zig-zag pattern having peaks 114 and valleys 116, or any suitable pattern. The strut segments 110 may each be coupled to at least one other strut segment 110 by a longitudinal connecting member 118.

Stents are typically implemented as either open cell stents or closed cell stents. A closed cell stent having each peak and valley of each strut segment connected to the peaks or valleys of adjacent strut segments except at the proximal and distal ends. Open cell stents, on the other hand, have some peaks and/or valleys that are not connected to peaks and/or valleys of adjacent strut segments. In a preferred embodiment, the stent 100 may be an open cell design, for example, minimizing the reduction in length of the stent 100 when expanding the stent 100 from a pre-deployed state to a deployed state. In addition, open cell scaffolds have an enhanced ability to expand and conform to the walls of non-circular lumens (e.g., sinuses) as compared to closed cell structures. For example, individual segments of an open cell stent may be less dependent on adjacent segments than in a closed cell design. Thus, the open cell segments are better suited to conform to the irregularities of non-circular lumens. Referring to fig. 3, the longitudinal connecting members 118 may be arranged in a periodic peak-to-valley connection scheme, for example, every third peak is connected to every third valley by the longitudinal connecting members 118. Although a peak-to-valley connection scheme with three periods is shown in fig. 3, other connection schemes and periods are contemplated. For example, the connection scheme may be a peak-to-peak connection scheme, an intermediate-to-intermediate connection scheme, a hybrid connection scheme, or any suitable connection scheme. As another example, the period may be two, four, a variable period, etc. Further, the longitudinal connecting members 118 may be flexible connections, non-flexible connections, a mixture of flexible and non-flexible connections, or any suitable connection.

the stent 100 may be sized to cover the sigmoid sinus and substantially the entire transverse sinus. For example, the length of the stent may be 6-9cm long, averaging about 7cm, depending on the size and height of the patient. Appropriately sized stents maintain patency of both sinus structures while substantially eliminating the possibility of re-collapse and substantially eliminating the possibility of stent occlusion.

The stent 100 may be made of nickel titanium (also known as nitinol) or any suitable material. In the case of nitinol stent 100, the collapsed stent 100 may be inserted into a body lumen, wherein body temperature warms the stent 100 and the stent 100 returns to its original expanded shape after removal of the constraining sheath, as described below with reference to fig. 5-10.

in various embodiments, the stent 100 may include segments 110 having strut members 112 of different flexibility. In particular, one or more segments 110 at the distal end 104 of the stent 100 may have greater flexibility than one or more segments 110 at the proximal end 102 of the stent 100. For example, as shown in fig. 2, stent 100 may have a first set of flexible segments 120 and a second set of rigid segments 130. The first set of flexible segments 120 may include eight or any suitable number of segments 110 and the second set of rigid segments 130 may include fourteen or any suitable number of segments 110. Stent 100 may transition from a group of flexible segments 120 to a group of rigid segments 130 at a transition point 142 between the two groups 120, 130. Fig. 3 shows a detail of the transition point 142 between the flexible segment 120 and the rigid segment 130. Additionally and/or alternatively, the stiffness of the segments 110 of the stent 100 may gradually increase from the distal end 104 to the proximal end 102 of the stent 100. For example, each segment 110 may have the same or greater flexibility in the direction of the proximal end 102 as adjacent segments 110.

In one exemplary embodiment, the flexibility of the segment 110 may correspond to a radially outward expansion strength (RES) of the segment 110. For example, the set of flexible segments 120 may have a lower RES than the set of rigid segments 130. Thus, if a stent is placed in the venous sinus, the set of flexible segments 120 with a low RES at the distal end 104 of the stent 100 supports and maintains the open transverse sinus region while not applying excessive pressure to the dural lining. The set of rigid segments 130 at the proximal end of the stent 100 and having a larger RES than the flexible segments 120 are positioned in the b-shaped region, which may contain excessive arachnoid granulation ingrowth and/or stenosis, which may require more force to open and restore better blood outflow. The transition from the low RES distal end 104 to the higher RES proximal end 102 of the stent 100 can be converted into a more flexible and integral transition within the stent delivery system 200. In particular, the integration of stent 100 in stent delivery system 200 provides for faster and easier delivery of stent 100 by improving the ability to navigate the sigmoid, for example, as described below with reference to fig. 9.

In various embodiments, the amount of RES and the flexibility of portions of the stent 100 may be configured based on the distance between stent segments 110 and/or the length of the longitudinal connecting members 118, the number of longitudinal connecting members 118, the amount of strut members 112, and/or the width of the strut members 112 and/or the longitudinal connecting members 118. For example, a greater distance between stent segments 110 and/or a longer longitudinal connecting member 118 may correspond to a lower RES and greater flexibility. As another example, a greater number of longitudinal connecting members 118 may correspond to a higher RES and greater stiffness. Further, a greater number of strut members 112 may correspond to a higher RES and greater stiffness. Additionally, narrower widths of the strut members 112 and/or the longitudinal connecting members 118 may correspond to lower RES and greater flexibility. For example, referring to fig. 3, the width of the strut members 112, strut member peaks 114, and longitudinal members 118 in the set of rigid segments 130 is referred to as W1. The width of the strut members 112, strut member peaks 114, and longitudinal members 118 in the set of flexible segments 120 is referred to as W2. The width W1 in the group of rigid segments 130 may be greater than the width W2 in the group of flexible segments 120. As one example, the width W1 of the strut members 112 and longitudinal members 118 in the set of rigid segments 130 can be about 0.0050 inch and the width W1 of the strut member peaks 114 can be about 0.0065 inch. In the group of flexible segments 120, the width W2 of the strut members 112 and the longitudinal connecting members 118 may be about 0.0045 inches and the width W2 of the strut member peaks 114 may be about 0.0060 inches. In certain embodiments, a reduction of about 10% in width W2 may correspond to a reduction of about 33% in stiffness for the set of flexible segments 120 as compared to the set of rigid portions 130.

Referring to FIG. 4, the stent 100 may be conical or stepped such that the lumen diameter D1/D2 of the stent 100 is larger at the proximal end 102 than at the distal end 104. For example, fig. 4 shows the profile of a cylindrical stent 100 that is conical and has a larger lumen diameter D1 of stent 100 at proximal end 102 than stent lumen diameter D2 at distal end 104. Additionally and/or alternatively, the stent 100 may have a mixture of straight and tapered portions. For example, the stent 100 may have straight portions at the distal end 104 and the proximal end 102 with a tapered portion between the straight portions. As another example, the stent 100 may have a straight portion at the distal end 104 followed by a tapered portion between the straight portion and the proximal end 102, or vice versa. The inclusion of the taper ensures different lumen diameters D1/D2 at the proximal end 102 and distal end 104 of the stent 100. In one exemplary embodiment, the diameter D1 at the proximal end 102 of the stent 100 is larger than the diameter D2 at the distal end 104. For example, the diameter D1 at the proximal end 102 may be about 0.3937 inches and the diameter D2 at the distal end 104 may be about 0.2756 inches. Thus, if the stent 100 is placed in the venous sinus, the smaller diameter D2 at the distal end 104 of the stent may be appropriately sized for the transverse sinus region and the transition to the larger diameter D1 at the proximal end 102 of the stent 100 may be appropriately sized for the sigmoid sinus region. In this way, contact of the strut member 112 with the dural wall scaffold in the transverse sinus region and the sigmoid sinus region may be maximized such that portions of the scaffold 100 are not left in the open blood flow of the lumen of the venous sinus.

Fig. 5 illustrates an exemplary stent delivery system 200 according to various embodiments. Fig. 6 illustrates a detailed view of portions 200A, 200B, 200C, 200D of the exemplary stent delivery system 200 of fig. 5, according to various embodiments. Fig. 7 illustrates a detailed view of the interior 200E of the stent delivery system 200 of fig. 5, according to various embodiments. Fig. 8 illustrates a detailed view of the exterior 200F of the stent delivery system 200 of fig. 5, according to various embodiments. Fig. 9 illustrates an exploded cross-sectional view of the interior 200E of the stent delivery system 200, the stent 100, and the exterior 200F of the stent delivery system 200 according to respective embodiments, wherein the flexibility of the stent delivery system 200 is shown to increase as the stent 100 moves from the proximal ends 102, 202 toward the distal ends 104, 204 of the system 200, by plotting to an exemplary flexibility diagram 300.

Referring to fig. 5-9, the stent delivery system 200 may include an outer portion 200F and an inner portion 200E extending between a proximal end 202 and a distal end 204 of the system 200.

The interior 200E of the stent delivery system 200 may include a delivery handle 210 at the proximal end 202, a delivery tip 290 at the distal end 204, and a shaft 220 extending from the delivery handle into the delivery tip 290. The shaft 220 can include a proximal portion connected to the shaft 222 of the delivery handle 210, a central portion of the shaft 224, and a distal portion including and/or extending through the shaft 226 of the pusher coil 270 and stent bed 280. In various embodiments, the shaft portions 222, 224, 226, 270, 280 may be tubular structures made of different materials and/or may have different outer diameters, for example, to increase flexibility along the longitudinal axis from the proximal end 202 to the distal end 204. For example, the proximal portion of the shaft 222 attached to the delivery handle and the central portion of the shaft 224 may be a hypotube or any suitable tube having a first diameter. The distal portion of the shaft 224 may have a second diameter that is smaller than the first diameter of the proximal portion 222 and the central portion 224, and/or may include portions made of different materials, such as the helical portion 270.

The stent bed 280 may be the portion of the distal shaft 226 between the pusher coil 270 and the delivery tip 290. The stent bed 280 may be a thin-walled polyimide tube with constant stiffness. The stent bed 280 may extend through a lumen in the pre-deployment stent 100 such that the pre-deployment stent 100 is positioned and carried on the stent bed 280 until deployed. Pre-deployed stent 100 positioned on stent bed 280 may be held in a pre-deployed state by sheath 260, and sheath 260 may be slid over stent 100, as described below. In various embodiments, the proximal and/or distal ends of the stent bed 280 may include one or more markers, such as radiopaque markers, to enhance visualization of the location of the pre-deployed stent 100 within the stent delivery system 200. For example, an operator of the stent delivery system 200 may monitor navigation of the system 200 via medical image data, such as fluoroscopic images, ultrasound images, or images in any suitable medical imaging modality. The markers are easily identifiable in the image data to assist the operator in accurately positioning the stent delivery system 200 in the region of the stent.

The pusher coil 270 may be part of the distal shaft 226 at the proximal end of the stent bed 280. Additionally and/or alternatively, the pusher coil 270 may be disposed concentrically between the distal shaft 226 and the sheath 260. The pusher coil 270 may act as a stop for the stent 100 positioned on the stent bed 280 by preventing the pre-deployed stent 100 from sliding from the stent bed 280 toward the proximal end 202. In various embodiments, the pusher coil 270 may have greater flexibility at the distal end of the pusher coil 270 than at the proximal end of the pusher coil 270. For example, the push coil 270 may have multiple portions, wherein each portion has increasing flexibility along the longitudinal axis from the proximal end of the push coil 270 to the distal end of the push coil 270.

the delivery tip 290 may include a distal end 294 and a proximal end 292. The delivery tip 290 may include a lumen configured to allow the guidewire 269 to pass through the delivery tip 290 such that the stent delivery system may slide over the guidewire 290 during navigation of the system to the stent region in the venous sinus or other body lumen. The delivery tip 290 may include a tip transition 296 at the proximal end 292 of the delivery tip 290. Tip transition 296 may have a larger outer diameter configured to prevent sheath 260 of outer portion 200F of stent delivery system 200 from sliding distally over delivery tip 290. In one exemplary embodiment, the delivery tip 290 can be made of a medical grade polymer, such as a polyether block amide, such as PEBAX, and can have a durometer of about 35.

In various embodiments, the stent delivery system 200 can include a quick-swap interface 268 through the sheath 260 and into the distal shaft section 226. The guidewire 269 extends within the guidewire lumen of the stent delivery system 200 from the lumen in the delivery tip 290 at the distal end 204 of the system 200 to the point where the guidewire lumen terminates outside of the system 200 at the distal shaft portion 226 and proximal the quick-exchange junction 268 at the distal sheath portion 266 of the pusher coil 270. The quick-exchange interface 268 may facilitate quick placement of the stent delivery system 200 over the guidewire 269 and allow for the use of a shorter guidewire than is used in over-the-wire catheter systems.

The outer portion 200F of the stent delivery system 200 may include sleeves 230, 240, 250 and a sheath 260. The sleeve may include a lock 230, a Tuohy Borst valve 240, and a luer flap 250. The lock 230 may be, for example, a standard luer lock or any suitable lock for connecting the tuohy borst valve 240 to the proximal portion 222 of the shaft 220. Lock 230 may be loosened to allow sleeves 230, 240, 250 and sheath 260 to slide over shaft 220 and tightened to prevent such movement. A Tuohy Borst valve (also referred to as a hemostasis valve) 240 may be attached to the lock 230 at a proximal end and may be coupled to the luer wing 250 at a distal end. The Tuohy Borst valve 240 may receive an internally inserted shaft 220, which shaft 220 may move within the valve 240 in a direction parallel to its longitudinal axis. The Tuohy Borst valve 240 may include a luer port 242 for securing the valve 240 to other medical instruments and devices that may be used during a procedure to deliver the stent 100 to a stent region in a patient. The luer wings 250 may be securely attached to the sheath 260. The shaft 220 is configured to extend through the lock 230, Tuohy Borst valve 240, luer wing 250, and sheath 260.

The sheath 260 can include a proximal portion 262 terminating in the luer wings 250, a distal portion 266 terminating in a tip transition 296 at the proximal end 292 of the delivery tip 290, and a central portion 264 between the proximal and distal portions 262, 266. In various embodiments, the sheath portions 262, 264, 266 may be tubular structures made of different materials and/or may have different outer diameters, for example, to increase flexibility along the longitudinal axis from the proximal end 202 to the distal end 204. Sheath 260 is configured to slide longitudinally over shaft 220 and stent 100 between a pre-deployment position and a deployed position. For example, in the pre-deployment position, sheath 260 extends over pre-deployment scaffold 100 to tip transition 296 of delivery tip 290. After navigating the stent delivery system 200 to the stent area, the sheath 260 can be pulled back over the stent 100 by releasing the lock 230 and pulling the sleeves 230, 240, 250 toward the delivery handle 210 at the proximal end 202 of the system 200. The stent 100 is deployed by expanding as the sheath 260 passes over and releases the stent 100 from its pre-deployed compressed state. In various embodiments, sheath 260 may include one or more markers, such as radiopaque markers, to enhance visualization in medical image data of the location of pre-deployed stent 100 within stent delivery system 200. In one exemplary embodiment, distal portion 266 of sheath 260 can be made of a medical grade polymer, such as a polyether block amide, such as PEBAX. In an exemplary embodiment, distal portion 266 of sheath 260 may include a distal-most segment 266a having a flexible durometer of about 35, an intermediate segment 266b having a semi-flexible durometer of about 55, and a proximal segment 266c having a rigid durometer of about 72. As such, distal portion 266 of sheath 260 may increase in stiffness from distal-most segment 266a to proximal segment 266 c.

Referring to fig. 9, a graph 300 is shown plotting the stiffness or flexibility 302 of the inner portion 200E of the combined stent delivery system 200, the stent 100, and the outer portion 200F of the stent delivery system 200. As shown in fig. 9, the stiffness 302 increases gradually and/or stepwise from the distal end 204 of the stent delivery system 200 with the loaded stent 100 toward the proximal end 202 of the system 200. For example, the delivery tip may have a durometer of about 35. As shown in fig. 9, the delivery tip 290 portion of the stent delivery system 200 may be the most flexible stiffness 302. The next segment in the proximal direction from the delivery tip 290 is the segment loaded with the stent bed 280 of the stent 100 and the distal portion of the sheath 266. Distal portion 266 of sheath 260 may have a distal-most segment 266a having a flexible durometer of about 35. Thus, the combination of the distal portion 266 of the sheath and the stent bed 280 and the set of flexible segments 120 of the stent 100 may have a greater stiffness 302 than the delivery tip 290. Continuing in the proximal direction, the combined stiffness 302 of the distal-most segment 266a of the distal portion of the sheath 266, the set of rigid segments 130 of the stent 100, and the stent bed 280 is increased by the set of rigid segments 130 of the stent 100.

The intermediate section 266b of the distal portion 266 of the sheath can have a semi-flexible durometer of about 55 and the proximal section 266c can have a rigid durometer of about 72. The push coil 270 may have a flexible section 272 with loose windings and a rigid section 274 with tight windings. Thus, the stiffness 302 continues to increase for the combination of the flexible segment 272 of the push coil 270 and the intermediate segment 266b of the distal portion of the sheath 266. In the same manner, the stiffness 302 is stepped up for the combination of the rigid section 274 of the coil and the intermediate section 266b of the distal portion of the sheath 266.

The distal shaft portion 226 in the proximal direction from the push coil 270 may have a greater stiffness than the coil. Thus, the stiffness 302 of the stent delivery system 200 with loaded stent 100 may again be stepped up for the combined system components including the distal shaft portion 226 in the proximal direction from the pusher coil 270 and the proximal section 266c of the distal portion 266 of the sheath 260.

In summary, not only does the different materials and different hardnesses of the various components affect the flexibility of the stent delivery system 200 with the loaded stent 100, but the combination of components that load the stent 100 along the longitudinal axis of the system 200 provides a gradual increase in stiffness 302 from the distal end 204 toward the proximal end 202 of the system 200 in a new manner, which improves the control and navigation of the system 200 for delivering the stent 100.

Fig. 10 is a flow chart 400 illustrating exemplary steps 402-410 that may be used to provide enhanced navigation of the stent delivery system 200 for placement of the stent 100, according to various embodiments. Referring to fig. 10, a flow chart 400 is shown including exemplary steps 402 through 410. Certain embodiments may omit one or more steps, and/or perform the steps in a different order than listed, and/or combine certain steps discussed below. For example, some steps may not be performed in some embodiments. As another example, certain steps may be performed in a different temporal order than listed below, including simultaneously.

At step 402, the stent delivery system 200 may be inserted into a venous sinus or other body lumen. For example, the stent delivery system 200 may access the venous sinus at the sigmoid junction via the jugular vein. Stent delivery system 200 may include a collapsed, pre-deployed stent 100 carried between shaft 220 and/or stent bed 280 and sheath 260 near distal end 203 of system 200. In various embodiments, stent 100 may be made of nitinol. Insertion of the stent delivery system 200 into the venous sinus or other body lumen provides a body temperature that warms the nitinol stent 100, which allows the stent 100 to return to its original expanded shape after the sheath 260 of the system is removed at step 408.

At step 404, the stent delivery system 200 is navigated to position the stent 100 at a target site in the venous sinus or other body lumen. For example, the stent delivery system 200 may access the venous sinus via the jugular vein, pass through the sigmoid sinus and the sigmoid sinus, and enter the transverse sinus. The target site or stent region for placement of the stent 100 may span substantially from the distal end of the transverse sinus into the sigmoid sinus. Navigation of stent delivery system 200 with stent 100 involves passing through a curved sigmoid. Thus, in various embodiments, both the stent 100 and the stent delivery system 200 may have increased flexibility from the proximal ends 102, 202 of the stent 100 and the catheter 200 to the distal ends 104, 204 of the stent 100 and the catheter 200. This gradual change in flexibility provides increased maneuverability at the distal ends 104, 204 while providing control of the stiffness of the system 200 toward the proximal end 102 of the system 200.

At step 406, lock 230 of stent delivery system 200 is released to allow sheath 260 to move over shaft 220 of system 200. For example, lock 230 may be unscrewed or otherwise loosened from shaft 220.

At step 408, catheter hub 230, 240, 250 may be pulled toward delivery handle 210 to slide sheath 260 back over stent 100, thereby deploying stent 100. For example, the sheath may be attached to the catheter hub 230, 240, 250 at the luer 250 such that the sheath 260 moves with the hub 230, 240, 250 when the hub 230, 240, 250 is pulled over the shaft 220.

At step 410, the delivery tip 290 may be pulled through the lumen in the deployed stent 100 and the stent delivery system 200 may be removed from the venous sinus or other body lumen. For example, removal of the sheath 260 at step 408 may deploy the collapsed stent 100 to an expanded state that opens the stent lumen. Thus, when the stent delivery system 200 is pulled back through and out of the venous sinus or other body lumen to remove the stent delivery system 200 from the patient, the delivery tip 290 of the stent delivery system 200 can be passed through the open stent lumen.

Aspects of the present invention provide a stent delivery system 200. According to various embodiments, stent delivery system 200 includes a delivery handle 210 at a proximal end 202 of stent delivery system 200, catheter sleeves 230, 240, 250, a delivery tip 290 at a distal end 204 of stent delivery system 200, a shaft 220, a stent 100, and a sheath 260. The delivery tip 290 includes a distal tip end 294 and a proximal tip end 292. The delivery tip 290 has a first flexibility. Shaft 220 extends from delivery handle 210 through catheter hubs 230, 240, 250 and into delivery tip 290. The shaft 220 includes a coil 270 and a stent bed 280. The coil 270 includes a coil distal end and a coil proximal end. The stent bed 280 is between the distal end of the coil and the distal proximal end 292. The stent 100 is loaded onto the stent bed 280 and includes a stent distal end 104, a stent proximal end 102, and a cylinder between the stent distal end 104 and the stent proximal end 102. The first portion 120 of the cylinder at the distal end 104 of the stent has greater flexibility than the second portion 130 of the cylinder at the proximal end 130 of the stent. The sheath 260 is coupled to the catheter sleeves 230, 240, 250 and is movable on the stent bed 280 between a pre-deployed position and a deployed position. Sheath 260 extends over stent bed 280 if in the pre-deployment position. If in the deployed position, sheath 260 is pulled back from stent bed 280. If in the pre-deployment position, stent 100 is compressed by sheath 260 over stent bed 280. If sheath 260 is pulled back from stent bed 280 in the deployed position, stent 100 expands. Sheath 260 includes a sheath distal end and a sheath proximal end. Sheath 260 includes a flexible segment 266a at the distal end of the sheath, a semi-flexible segment 266b adjacent flexible segment 266a, and a rigid segment 266c adjacent semi-flexible segment 266 b. The combination of stent bed 280, first portion 120 of the cylinder of stent 100, and flexible segment 266a of sheath 260 has a second flexibility that is less than the first flexibility. The combination of stent bed 280, second portion 130 of the cylinder of stent 100, and flexible segment 266a of sheath 260 has a third flexibility that is less than the second flexibility.

In various embodiments, the coil 270 includes a loosely wound region 272 at the distal end of the coil that has greater flexibility than a tightly wound region 274 of the coil 270 at the proximal end of the coil. In certain embodiments, the combination of the loosely wound region 272 of the coil 270 and the semi-flexible section 266b of the sheath 260 has a fourth flexibility that is less than the third flexibility. In one exemplary embodiment, the combination of the tightly wound region 274 of the coil 270 and the semi-flexible segment 266b of the sheath 260 has a fifth flexibility that is less than the fourth flexibility. In various embodiments, the combination of the tightly wound region 274 of the push coil 270 and the rigid section 266c of the sheath 260 has a sixth flexibility that is less than the fifth flexibility. In some embodiments, the combination of shaft 220 adjacent coil 270 at the proximal end of the coil and rigid section 266c of sheath 260 has a seventh flexibility that is less than the sixth flexibility.

In one exemplary embodiment, one or more of delivery tip 290 and sheath 260 are made of a medical grade polymer, such as a polyether block amide. In various embodiments, the stent bed 280 is a thin-walled tube with constant stiffness. In some embodiments, the delivery tip 290 has a durometer of about 35. In one exemplary embodiment, one or more flexible segments 266a of sheath 260 have a durometer of about 35, semi-flexible segment 266b of sheath 260 has a durometer of about 55, and rigid segment 266c of sheath 260 has a durometer of about 72.

various embodiments provide a stent 100 comprising a distal end 104 having a first diameter D2, a proximal end 102 having a second diameter D1 greater than the first diameter D2, and a cylindrical body between the distal end 104 and the proximal end 102. The cylindrical body includes circumferential post segments 110 and longitudinal connecting members 118. Each circumferential strut section 110 includes strut members 112 arranged in a pattern. Each circumferential strut section 110 is connected to at least one other circumferential strut section 110 by a portion of the longitudinal connecting member 118. The first plurality of circumferential strut segments 120 at the distal end 104 of the stent 100 has greater flexibility than the second plurality of circumferential strut segments 130 at the proximal end 102 of the stent 100.

In certain embodiments, the first plurality of circumferential strut segments 120 at the distal end 104 of the stent 100 has a lower radially outward expansion strength than the second plurality of circumferential strut segments 130 at the proximal end 102 of the stent 100. In one representative embodiment, at least a portion of the cylinder is conical. In various embodiments, the longitudinal connecting members 118 are arranged in an open cell design. In some embodiments, the cylinder is made of nickel titanium. In one exemplary embodiment, the cylinder is 6 to 9 centimeters in length.

In various embodiments, the pattern of strut members 112 is a zigzag pattern having peaks 114 and valleys 116. In certain embodiments, the longitudinal connecting members 118 are arranged in a periodic peak-to-valley connection scheme. In one representative embodiment, the first width W2 of one or both of the strut members 112 and longitudinal connecting members 118 of the first plurality 120 of circumferential strut segments at the distal end 104 of the stent 100 is less than the second width W1 of one or both of the strut members 112 and longitudinal connecting members 118 of the second plurality 130 of circumferential strut segments at the proximal end 102 of the stent 100. In various embodiments, the first plurality 120 of circumferential strut segments at the distal end 104 of the stent 100 is 8 circumferential strut segments 110 and the second plurality 130 of circumferential strut segments at the proximal end 102 of the stent 100 is 14 circumferential strut segments 110.

As used herein, "and/or" means any one or more of the items in the list connected by "and/or". As an example, "x and/or y" means any element in the three-element group { (x), (y), (x, y) }. As another example, "x, y, and/or z" represents any element in the seven-element group { (x), (y), (z), (x, y), (x, z), (y, z), (x, y, z) }. The term "exemplary", as used herein, means serving as a non-limiting example, instance, or illustration. As used herein, the terms "for example" and "such as" list one or more non-limiting examples, or illustrations. As used herein, a structure that is "configured" or "operable" to perform a function requires that the structure not only be capable of performing the function, but actually be caused to perform the function, regardless of whether the function is actually performed.

while the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.