Embolization Microcatheter for Delivery of Beads to Peripheral Vascular Systems

Abstract

1. An embolization microcatheter comprising an elongate body and a distal section, the distal section comprising an offset portion and a winding portion, the winding portion comprising approximately one-half of a loop of a three-dimensional helix, a longitudinal axis of the winding portion being offset and / or disposed at an acute angle relative to a longitudinal axis of the elongate body, and the offset portion being disposed at an angle of about 60° to about 120° relative to the longitudinal axis of the elongate body.

Description

[Technical field]

[0001] The present disclosure relates generally to the field of microcatheters for embolization, and specifically to embolization catheters suitable for navigating within blood vessels for delivery of embolic beads to peripheral blood vessels. [Background technology]

[0002] Transarterial embolization, tumor embolization, or transcatheter arterial embolization (TAE) involves the administration of embolic material (which may include chemotherapy and / or radiotherapy agents) directly into a tumor (e.g., a liver tumor) via a microcatheter.

[0003] Embolization of tumors is usually performed with the aid of microcatheters, due to the need to selectively affect the tumor while avoiding as much damage as possible to healthy tissue. A major problem associated with embolization is "non-targeted embolization", where the embolic material travels to blood vessels other than those directly supplying the target tumor or tumor area, thus damaging healthy tissue with unpleasant and even dangerous consequences.

[0004] During embolization, the embolization catheter must be advanced and navigated through small and often tortuous vessels. Access to these vessels is difficult, if not eliminated, when using standard microcatheters. Furthermore, tracking of the microcatheter's progress within the vessels is limited due to the microcatheter's structure.

[0005] Thus, there remains a need for a microcatheter that can deliver embolic beads into small, tortuous blood vessels and facilitate navigation and reliable real-time tracking during the embolization procedure. Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure relates to embolization microcatheters suitable for navigation within small, tortuous blood vessels while facilitating reliable real-time tracking during embolization procedures. [Means for solving the problem]

[0007] This is advantageously accomplished by the unique construction of the embolization microcatheter having an elongated main body and a distal section including an offset portion and a winding portion, the winding portion having about half a loop of a three-dimensional helix, with the longitudinal axis of the winding being offset and / or disposed at an acute angle relative to the longitudinal axis of the elongated body.

[0008] Advantageously, the distal-most turns of the embolization microcatheter allow for a "screw-like" motion, thus facilitating advancement of the microcatheter within the blood vessel, even in tortuous sections.

[0009] Additionally, the three-dimensional structure of the embolization microcatheter, and in particular the offset of the distal wraps disclosed herein according to some embodiments, advantageously provides a "line-of-sight" of the tip of the microcatheter as it advances through the vessel, which may not be readily achieved with standard two-dimensional microcatheters, where the tip section is obstructed by the elongated body of the microcatheter and therefore is not seen when viewing the tip from a proximal perspective.

[0010] Furthermore, the three-dimensional structure of the embolization microcatheter disclosed herein, according to some embodiments, may advantageously facilitate anchoring the microcatheter within the blood vessel by contacting at least two points of the vessel wall, such contact points contributing to stabilization of the microcatheter within the blood vessel, which is very important especially during delivery of embolization beads.

[0011] In operation, the embolization microcatheter disclosed herein, according to some embodiments, when inserted into a blood vessel, advances in a "screw-like" motion facilitated by the windings of its distal section. The user often advances the microcatheter in a small, tortuous vessel, and the windings offset from the elongated body can be observed during the procedure. This facilitates navigation of the microcatheter within the vessel. During the procedure, the user can also utilize the three-dimensional structure of the embolization microcatheter to contact the vessel wall at two or more points. This allows stabilization of the microcatheter within the vessel, facilitating safer and more precise execution of the procedure.

[0012] According to some embodiments, an embolization microcatheter is provided that includes an elongate body and a distal section. The distal section includes an offset portion and a winding portion, the winding portion comprising approximately half of a loop of a three-dimensional helix, such that a longitudinal axis of the winding portion is offset and / or disposed at an acute angle relative to a longitudinal axis of the elongate body, the offset portion being disposed at an angle of about 60° to about 120° relative to the longitudinal axis of the elongate body. According to some embodiments, the winding portion is configured to longitudinally steer the microcatheter with a screw-like motion, thereby preventing the distal section of the microcatheter from collapsing, bending, kinking, backwards movement, whipping, lashing, or any combination thereof. Advantageously, the screw-like motion allows the distal section to be steered with controlled and / or precise movements into certain vessels, such as small side branches that are typically difficult to reach without multiple back and forth movements.

[0013] According to some embodiments, the offset portion is curved.

[0014] According to some embodiments, the longitudinal axis of the windings may be offset from the longitudinal axis of the elongate body by about 0.5 mm to about 5 mm.

[0015] According to some embodiments, the acute angle at which the longitudinal axis of the windings is disposed relative to the longitudinal axis of the elongate body may be between about 10° and about 60°.

[0016] According to some embodiments, the length of the turns is between about 5 mm and about 20 mm. According to some embodiments, the ratio of the length of the turns to the radius or average radius defined by the half loop is between about 2 and about 20.

[0017] According to some embodiments, the three-dimensional spiral is right-handed. According to some embodiments, the three-dimensional spiral is left-handed. According to some embodiments, the three-dimensional spiral is a helix.

[0018] According to some embodiments, the distal section may be pre-shaped / pre-formed, for example in a wound / curled / coiled configuration.

[0019] According to some embodiments, the body and offset portion may together define a non-planar curve.

[0020] According to some embodiments, the elongate body may further include a filter section including a plurality of side openings formed in a wall of the elongate body, the side openings may be in the form of slits having a length of about 200 μm to about 800 μm and a width of about 25 μm to about 100 μm.

[0021] According to some embodiments, the embolization microcatheter may include a wall having an inner layer, an outer layer, and a scaffold interposed between the inner layer and the outer layer. According to some embodiments, the outer layer section of the outer layer of the distal section may be more flexible than the outer layer section of the outer layer of the elongate body.

[0022] According to some embodiments, the distal section may be dimensioned such that when inserted into a tortuous vessel, different portions of the distal section contact opposite sides of the tortuous vessel at different longitudinal positions of the tortuous vessel.

[0023] According to some embodiments, the embolization microcatheter may be configured for guidewire-free navigation.

[0024] According to some embodiments, the offset portions are configured to minimize interference with the user's field of vision by the wound portion.

[0025] According to some embodiments, a method for performing an embolization procedure is provided, the method comprising inserting and advancing an embolization microcatheter into a blood vessel and performing an embolization procedure, the embolization microcatheter comprising an elongate body and a distal section, the distal section comprising an offset portion and a winding portion, the winding portion comprising approximately one-half of a loop of a three-dimensional helix, a longitudinal axis of the winding portion being offset and / or disposed at an acute angle relative to a longitudinal axis of the elongate body, the offset portion being disposed at an angle of about 60° to about 120° relative to the longitudinal axis of the elongate body.

[0026] According to some embodiments, a method for manufacturing an embolization microcatheter distal section defining a non-planar curve is provided, the method comprising: providing a three-dimensional mandrel including an offset portion and a winding portion; and forming an embolization microcatheter on the mandrel in a thermal chamber, thereby manufacturing an embolization microcatheter having a shape of the mandrel, the winding portion comprising approximately one-half of a loop of a three-dimensional helix, a longitudinal axis of the winding portion being offset and / or disposed at an acute angle relative to a longitudinal axis of an elongate body, and the offset portion being disposed at an angle of about 60° to about 120° relative to the longitudinal axis of the elongate body.

[0027] Particular embodiments of the present disclosure may include some, all, or any of the above characteristics. One or more technical advantages will be readily apparent to those skilled in the art from the drawings, descriptions, and claims contained herein. Furthermore, although certain characteristics are enumerated above, various embodiments may include all, some, or none of the enumerated characteristics.

[0028] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments are further expanded in the drawings and detailed description that follow. [Brief description of the drawings]

[0029] The features, nature, and advantages of the present disclosure will become more apparent from the detailed description set forth below when considered in conjunction with the drawings in which like reference characters identify correspondingly throughout. Identical structural elements or parts that appear in more than one figure are generally labeled with the same number in all figures in which they appear. Alternatively, elements or parts that appear in more than one figure may be labeled with different numbers in the different figures in which they appear. Dimensions of components and features in the figures are selected for convenience and clarity of presentation and are not necessarily shown to scale. The drawings are listed below. [Figure 1] FIG. 1 presents a schematic perspective view of an embolization microcatheter including an elongate body and a distal section, according to some embodiments. [Figure 2A] FIG. 2A presents a schematic side view of the distal section of the embolization microcatheter of FIG. 1 from a perspective oriented along the negative z-axis (as shown), according to some embodiments. [Figure 2B] FIG. 2B presents a schematic side view of the distal section of the embolization microcatheter of FIG. 1 from a perspective oriented along the positive z-axis, according to some embodiments. [Figure 3A] FIG. 3A presents a schematic side view of the distal section of the embolization microcatheter of FIG. 1 from a perspective oriented along the negative y-axis (as shown), according to some embodiments. [Figure 3B] FIG. 3B presents a schematic side view of the distal section of the embolization microcatheter of FIG. 1 from a perspective oriented along the positive y-axis, according to some embodiments. [Figure 4A] FIG. 4A presents a schematic front view of the embolization microcatheter of FIG. 1, according to some embodiments. [Figure 4B]FIG. 4B presents a schematic rear view of the embolization microcatheter of FIG. 1, according to some embodiments. [Figure 5A] FIG. 5A presents a schematic side view of the embolization microcatheter of FIG. 1 from a perspective pointing substantially midway along a direction between the negative y-axis and the negative z-axis on the yz plane, according to some embodiments. [Figure 5B] FIG. 5B presents a schematic side view of the embolization microcatheter of FIG. 1 from a perspective pointing substantially midway along a direction between the positive y-axis and the positive z-axis on the yz plane, according to some embodiments. [Figure 6A] FIG. 6A presents a schematic cross-sectional view of the embolization microcatheter of FIG. 1 from the perspective of FIG. 5A, according to some embodiments, where the cross-section bisects the body along a plane perpendicular to the direction defined by the perspective. [Figure 6B] FIG. 6B presents a schematic cross-sectional view of the embolization microcatheter of FIG. 1 from the perspective of FIG. 5B, according to some embodiments, where the cross-section bisects the body along a plane perpendicular to the direction defined by the perspective. [Figure 7] FIG. 7 shows a histogram of average peak tracking force for an embolization microcatheter disclosed herein according to some embodiments (designated "Drakon") compared to other embolization microcatheters. [Figure 8] FIG. 8 shows a histogram of advancing distance through tortuous anatomy achieved by an embolization microcatheter disclosed herein according to some embodiments (designated "Drakon") compared to other embolization microcatheters. [Figure 9] FIG. 9 shows a histogram of tip response to torque for an embolization microcatheter disclosed herein according to some embodiments (designated "Drakon") compared to other embolization microcatheters. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details to provide a thorough understanding of the various concepts. However, it will also be apparent to those skilled in the art that these concepts may be practiced without the specific details presented herein. In some instances, well-known features may be omitted or simplified to avoid obscuring the present disclosure.

[0031] One of the main challenges of embolization microcatheters is their navigation within small, tortuous vessels while at the same time facilitating reliable real-time tracking of the microcatheter advancement during the embolization procedure.

[0032] Advantageously, these requirements are met by the microcatheter and its structural features disclosed herein.

[0033] Thus, according to some embodiments, provided herein is an embolization microcatheter comprising an elongate body and a distal section. The distal section comprises an offset portion and a winding portion. The winding portion comprises approximately half of a loop of a three-dimensional helix, and a longitudinal axis of the winding portion is offset and / or disposed at an acute angle relative to the longitudinal axis of the elongate body. The offset portion is disposed at an angle of about 60° to about 120° (e.g., about 60° to about 80°, about 80° to about 100°, or about 100° to about 120°) relative to the longitudinal axis of the elongate body. The offset portion may be curved.

[0034] According to some embodiments, the longitudinal axis of the spool may be offset relative to the longitudinal axis of the elongate body by about 0.5 mm to about 5 mm (e.g., about 0.5 mm to about 1 mm, about 1 mm to about 3 mm, or about 3 mm to about 5 mm, each possibility pre-determining a separate embodiment).

[0035] According to some embodiments, the acute angle at which the longitudinal axis of the spool is disposed relative to the longitudinal axis of the elongate body is between about 10° and about 60°, e.g., between about 10° and about 30°, between about 30° and about 40°, or between about 40° and about 60°, each possibility pre-defined as a separate embodiment.

[0036] According to some embodiments, the length of the spool is from about 5 mm to about 20 mm, e.g., from about 5 mm to about 10 mm, from about 10 mm to about 15 mm, or from about 15 mm to about 20 mm, each possibility predefined as a separate embodiment.

[0037] According to some embodiments, the ratio of the length of the turns to the radius or average radius defined by the half-loops is from about 2 to about 20, e.g., from about 2 to about 5, from about 5 to about 10, or from about 10 to about 20, each possibility presetting a separate embodiment.

[0038] According to some embodiments, the microcatheter 100 may have a length of at least 50 cm, at least 60 cm, at least 75 cm, or at least 1 m. Each possibility is a separate embodiment. Each possibility is a separate embodiment.

[0039] According to some embodiments, the three-dimensional spiral may be right-handed. According to some embodiments, the three-dimensional spiral may be left-handed. According to some embodiments, the three-dimensional spiral may be a helix. According to some embodiments, the distal section may be pre-formed.

[0040] According to some embodiments, the body and offset portion together define a non-planar curve.

[0041] According to some embodiments, the elongate body may further comprise a filter section including a plurality of side openings formed in a wall of said elongate body. The side openings may be in the form of slits having a length of about 200 μm to about 800 μm and a width of about 25 μm to about 100 μm; e.g., a length of about 200 μm to about 300 μm and a width of about 75 μm to about 100 μm; or a length of about 600 μm to about 800 μm and a width of about 25 μm to about 50 μm; or a length of about 500 μm to about 800 μm and a width of about 50 μm to about 100 μm; or a length of about 200 μm to about 400 μm and a width of about 25 μm to about 50 μm, each possibility being predefined in a separate embodiment.

[0042] According to some embodiments, the embolization microcatheter has a wall including an inner layer, an outer layer, and a scaffold interposed between the inner layer and the outer layer, the outer layer section of the outer layer of the distal section may be more flexible than the outer layer portion of the outer layer of the elongate body.

[0043] According to some embodiments, the distal section may be dimensioned such that when inserted into a tortuous vessel, different portions of the distal section contact opposite sides of the tortuous vessel at different longitudinal positions of the vessel.

[0044] As used herein, the terms "embolization," "transcatheter embolization," "transcatheter arterial embolization," and "TAE" may be used interchangeably and refer to the passage and lodging of an embolus within the bloodstream for therapeutic purposes, such as for example, as a hemostatic treatment for bleeding or as a treatment for some types of cancer by intentionally blocking blood vessels to starve tumor cells.

[0045] As used herein, according to some embodiments, the term "winding" may refer to a section of a microcatheter that has a non-straight, curved, twisted, bent, helical, coiled and / or partially coiled shape, and / or has one or more loops / partial loops.

[0046] As used herein, according to some embodiments, the term "offset portion" may refer to a section of the microcatheter that connects between the elongate body and the windings of the microcatheter and is shaped to create an offset and / or an (acute) angle between the longitudinal axis of the windings and the longitudinal axis of the elongate body.

[0047] Reference is now made to Figure 1, which illustrates a schematic perspective view of an embolization microcatheter 100 including an elongate body 102 and a distal section 104, according to some embodiments. The distal section 104 includes an offset portion 106 and a winding portion 108. The embolization microcatheter 100 extends from a proximal end opening 112 to a distal end opening 114.

[0048] As used herein, the terms "distal end opening" and "proximal end opening" refer to the end openings of the microcatheter that lead into the lumen of the microcatheter.

[0049] Dashed line "A" represents a central longitudinal axis of the embolization microcatheter 100 extending from the elongate body 102 and the distal section 104, which includes the offset portion 106 and the winding portion 108.

[0050] The offset portion 106 is disposed at a predetermined angle (e.g., about 60° to about 120°) relative to the longitudinal axis of the elongate body 102, such that the winding portion 108 forms approximately one-half of a loop of a three-dimensional helix, and the longitudinal axis of the winding portion 108 is offset relative to the longitudinal axis of the elongate body 102.

[0051] Reference is now made to Figures 2A-6B, which provide various views of embolization microcatheter 100. That is, element or part numbers in Figure 1 apply to the same elements or parts in Figures 2A-6B.

[0052] 2A presents a schematic side view of the distal section of the embolization microcatheter 100 of FIG. 1 from a perspective oriented along the negative z-axis (as shown), according to some embodiments, noting that offset portion 106 (and elongate body 102) are set beyond the dashed vertical line but are not shown.

[0053] 2B presents a schematic side view of the distal section of the embolization microcatheter 100 of FIG. 1 from a perspective oriented along the positive z-axis (as shown), according to some embodiments. Note that the elongated body 102 continues beyond the dashed vertical line, but is not shown in the figure.

[0054] 3A presents a schematic side view of the distal section of the embolization microcatheter 100 of FIG. 1 from a perspective oriented along the negative y-axis (as shown), according to some embodiments. Note that the elongated body 102 continues beyond the dashed vertical line, but is not shown in the figure.

[0055] 3B presents a schematic side view of the distal section of the embolization microcatheter 100 of FIG. 1 from a perspective oriented along the positive y-axis (as shown), according to some embodiments. Note that the elongated body 102 continues beyond the dashed vertical line, but is not shown in the figure.

[0056] FIG. 4A presents a schematic front view of the embolization microcatheter 100 of FIG. 1 (from a perspective toward the distal end opening 114), according to some embodiments.

[0057] 4B presents a schematic rear view (from a perspective toward the proximal end opening 112) of the embolization microcatheter 100 of FIG. 1, according to some embodiments. Note that in this perspective, the elongate body 102 cannot be seen as being "hidden" behind the proximal end opening 112, while only the offset portion 106 and the spool portion 108 are visible.

[0058] 5A presents a schematic side view of the embolization microcatheter 100 of FIG. 1 from a perspective pointing substantially midway along a direction between the negative y-axis and the negative z-axis on the yz plane, according to some embodiments. Note that the elongated body 102 continues beyond the dashed vertical line, but is not shown in the figure.

[0059] 5B presents a schematic side view of the embolization microcatheter of FIG. 1 from a perspective pointing substantially midway along a direction between the positive y-axis and the positive z-axis on the yz plane, according to some embodiments. Note that the elongated body 102 continues beyond the dashed vertical line, but is not shown in the figure.

[0060] 6A presents a schematic cross-sectional view of the embolization microcatheter 100 of FIG. 1 from the perspective of FIG. 5A, according to some embodiments. The cross-section bisects the body along a plane perpendicular to the direction defined by the perspective. Note that in this cross-sectional view, the turns 108 (or at least a portion thereof) are not visible due to their angle.

[0061] 6B presents a schematic cross-sectional view of the embolization microcatheter 100 of FIG. 1 from the perspective of FIG. 5B, where the cross-section bisects the body along a plane perpendicular to the direction defined by the perspective, in accordance with some embodiments. In this cross-sectional perspective, in contrast to the cross-sectional perspective of FIG. 6A, the turns 108 are not visible and are not in the cross-section.

[0062] Reference is now made to Figures 7-11, which present experimental results demonstrating the better performance of the embolization microcatheter disclosed herein in accordance with certain embodiments (designated "Drakon") as compared to other embolization microcatheters.

[0063] FIG. 7 shows a histogram of the average peak tracking force of an embolization microcatheter disclosed herein according to some embodiments (designated as "Drakon") compared to other embolization microcatheters (Test Protocol RD-039; n=5). The lowest trackable force [N] is obtained for the Drakon compared to other commercially available embolization microcatheters designated as Commercial Products 1-5. Lower trackable force indicates better maneuverability.

[0064] 8 shows a histogram of advancement distance through a tortuous anatomy achieved by an embolization microcatheter disclosed herein according to some embodiments (designated "Drakon") compared to another commercially available embolization microcatheter (Test Protocol RD-055; n=5). It can be seen that the Drakon embolization microcatheter is able to advance further through the tortuous anatomy (model) than the other microcatheters tested.

[0065] 9 shows a histogram of the tip response to torque of an embolization microcatheter disclosed herein according to some embodiments (designated "Drakon") compared to another commercially available embolization microcatheter (Test Protocol RD-018; n=5). As can be seen from the histogram, the Drakon showed the smallest tip torque response to torque, as measured by the average number of turns to 0.02 cN*m.

[0066] As used herein, the terms "approximately" and "about" refer to + / - 10%, or + / - 5%, or + / - 2% of the range to which it refers. Each possibility is a separate embodiment.

[0067] While several exemplary aspects and embodiments have been described above, those skilled in the art will envision certain modifications, additions, and subcombinations thereof, and it is therefore intended that the following claims be interpreted to include all such modifications, additions, and subcombinations that are within their true spirit and scope.

Claims

1. 1. An embolization microcatheter comprising an elongate body and a distal section, the distal section comprising an offset portion and a spool portion, the winding comprises approximately half of a loop of a three-dimensional helix, and the longitudinal axis of the winding is offset and / or disposed at an acute angle with respect to the longitudinal axis of the elongate body; the offset portion is disposed at an angle of about 60° to about 120° relative to a longitudinal axis of the elongate body; An embolization microcatheter, wherein the winding portion is configured to longitudinally manipulate the microcatheter in a screw-like motion, thereby preventing collapse and / or vibration and / or whipping of the distal section of the microcatheter.

2. The embolization microcatheter of claim 1 , wherein the offset portion is curved.

3. The embolization microcatheter of claim 1 , wherein the longitudinal axis of the windings is offset from the longitudinal axis of the elongate body by about 0.5 mm to about 5 mm.

4. 10. The embolization microcatheter of claim 1, wherein the acute angle at which the longitudinal axis of the windings is disposed relative to the longitudinal axis of the elongate body is between about 10 degrees and about 60 degrees.

5. The embolization microcatheter of claim 1, wherein the length of the wrap is between about 5 mm and about 20 mm.

6. 10. The embolization microcatheter of claim 1, wherein the ratio of the length of the turns to the radius or average radius defined by the half-loop is from about 2 to about 20.

7. The embolization microcatheter of claim 1 , wherein the three-dimensional spiral is right-handed.

8. The embolization microcatheter of claim 1 , wherein the three-dimensional helix is ​​left-handed.

9. The embolization microcatheter of claim 1 , wherein the three-dimensional spiral is a helix.

10. The embolization microcatheter of claim 1 , wherein the distal section is pre-shaped.

11. The embolization microcatheter of claim 1 , wherein the body and the offset portion together define a non-planar curve.

12. The embolization microcatheter of any one of claims 1 to 11, wherein the elongate body further comprises a filter section comprising a plurality of side openings formed in a wall of the elongate body.

13. 13. The embolization microcatheter of claim 12, wherein the side opening is in the form of a slit having a length of about 200 μm to about 800 μm and a width of about 25 μm to about 100 μm.

14. 10. The embolization microcatheter of claim 1, comprising a wall including an inner layer, an outer layer, and a scaffold interposed between the inner and outer layers.

15. The embolization microcatheter of claim 14, wherein the outer layer section of the outer layer of the distal section is more flexible than the outer layer section of the outer layer of the elongate body.

16. 10. The embolization microcatheter of claim 1, wherein the distal section is sized such that, when inserted into a tortuous vessel, different portions of the distal section contact opposite sides of the tortuous vessel at different longitudinal positions of the tortuous vessel.

17. The embolization microcatheter of claim 1 configured for guidewire-free navigation.

18. The embolization microcatheter of claim 1 , wherein the offset portion is configured to minimize interference with a user's field of view by the spool portion.

19. 1. A method for manufacturing an embolization microcatheter distal section defining a non-planar curve, comprising: providing a three-dimensional mandrel including an offset portion and a winding portion; and forming an embolization microcatheter tube on the mandrel in a heat chamber, thereby producing an embolization microcatheter having the shape of the mandrel, wherein the winding portion comprises approximately half of a loop of a three-dimensional helix, and wherein a longitudinal axis of the winding portion is offset and / or disposed at an acute angle with respect to a longitudinal axis of the elongate body; The offset portion is disposed at an angle between about 60° and about 120° relative to the longitudinal axis of the elongate body.

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