Catheter with dual concave side openings

Abstract

In some examples, a catheter includes an elongated body defining one or more lumens, and the elongated body includes a sidewall defining a side opening in fluid communication with a lumen of the one or more lumens. The side opening has a proximal end, a distal end, a first side extending from the proximal end to the distal end, and a second side opposite the first side and extending from the proximal end to the distal end. When the elongated body is straight, the first and second sides curve toward each other between the proximal and distal ends, for example to define a double concave shape.

Description

Technical Field

[0001] This disclosure relates to medical catheters. Background Technology

[0002] Medical catheters with at least one lumen have been proposed for use with various medical procedures. For example, in some cases, medical catheters can be used to extract and introduce fluid from and into a subject's body cavities, tubes, blood vessels, and other hollow anatomical structures. As an example, catheters can be used in hemodialysis procedures, in which blood is extracted from a patient's blood vessels for processing and then returned to the blood vessels for circulation. Summary of the Invention

[0003] In some aspects, this disclosure describes example catheters comprising an elongated body defining one or more side openings, the shape of which is configured to allow fluid to flow efficiently into and out of the lumen of the catheter body during, for example, a hemodialysis procedure. The side opening shapes described herein may be referred to as biconcave shapes because the side openings are concave on both sides when the elongated body is straight. In some instances, the biconcave side openings have a proximal end, a distal end, a first side, and a second side opposite the first side, wherein the first and second sides each extend from the proximal end to the distal end and curve toward each other between the proximal and distal ends. As an example, the first and second sides may each define a continuous curve that curves toward the other of the first or second sides in a direction toward the midpoint of the respective first or second side. Additionally, in some instances, the proximal and distal ends of the side openings may be curved.

[0004] In addition to having a biconcave shape, in some instances, when the elongated body is straight, the side opening is skewed relative to the longitudinal axis of the elongated body. This can further facilitate achieving the desired fluid flow properties for one or more medical procedures, such as hemodialysis. The side opening can be skewed relative to the longitudinal axis of the elongated body when, for example, the proximal and distal ends of the side opening are not aligned with each other along an axis parallel to the longitudinal axis of the elongated body when the elongated body is straight, and are circumferentially offset when the cross-section of the elongated body is circular. This position of the side opening relative to the longitudinal axis of the elongated body, and in some instances relative to the direction of fluid flowing through the lumen of the elongated body, can further improve the efficiency of fluid flow into and out of the lumen of the catheter body through the side opening.

[0005] In some instances, the catheter includes two side openings with a biconcave shape, each in fluid communication with a corresponding lumen of the catheter. In some instances, the side openings may be diametrically opposed to each other and axially aligned along the longitudinal axis of the elongated body, or in other instances, they may be axially offset from each other along the longitudinal axis of the elongated body.

[0006] In some instances, in addition to or instead of the side openings described herein, the catheter includes a catheter tip defining a tip lumen that is in fluid communication with only one lumen of the catheter, even in instances where the catheter includes multiple lumens. In instances where the catheter tip has only one lumen, the catheter tip may be asymmetrical and / or may have a smaller volume compared to some existing hemodialysis catheter tips. A smaller volume tip can increase the non-invasive properties of the catheter and / or improve the catheter's navigation through the patient's vascular system to the target site.

[0007] Details of one or more aspects of this disclosure are set forth in the following drawings and description. Other features, objects, and advantages of the technology described in this disclosure will become apparent from the specification, drawings, and claims. Attached Figure Description

[0008] Figure 1 It is a perspective view of an example catheter containing at least one side opening in fluid communication with the corresponding lumen.

[0009] Figure 2 yes Figure 1 A perspective view of the distal portion of the catheter.

[0010] Figure 3A yes Figure 1 Side elevation view of the distal portion of the duct.

[0011] Figure 3B yes Figure 1 Another side elevation view of the distal portion of the catheter, showing the catheter's relationship with... Figure 3A The sides shown are different sides.

[0012] Figure 3C yes Figure 1 Another side elevation view of the distal portion of the catheter, showing the catheter's relationship with... Figure 3A and 3B The sides shown are different sides.

[0013] Figure 4 An example side opening with a double concave shape is shown.

[0014] Figure 5 yes Figure 1 A schematic cross-sectional view of the distal portion of the catheter, wherein the cross-section is along... Figure 3A It was cut from line 5-5 in the middle.

[0015] Figure 6 yes Figure 1 A schematic cross-sectional view of the distal portion of the catheter, wherein the cross-section is along... Figure 3AIt was cut from line 6-6 in the middle.

[0016] Figure 7 yes Figure 1 The image shows an end view of the distal portion of the catheter, and also shows the end of the distal portion when viewed from the proximal direction.

[0017] Figure 8 This is another example of a distal portion of a conduit that includes a lateral opening not along the diameter.

[0018] Figure 9 yes Figure 8 A schematic cross-sectional view of the distal portion of the catheter, wherein the cross-section is in relation to... Figure 8 The image shown was cropped from a plane parallel to it.

[0019] Figure 10 yes Figure 1 Exploded view of the catheter and example catheter tip.

[0020] Figure 11 yes Figure 10 Side view of the catheter tip.

[0021] Figure 12 yes Figure 10 The end view of the catheter tip, and shows the catheter tip's relationship with... Figure 7 The ends shown are opposite each other. Detailed Implementation

[0022] Unless otherwise defined, all technical and scientific terms used generally have the same meaning as commonly understood by one of ordinary skill in the art.

[0023] The articles “a” and “a kind” are used to refer to one or more (i.e., at least one) grammatical objects of the article. For example, “element” means one / a kind of element or multiple / a kind of element.

[0024] In some instances, the term "axis line" refers to a fixed reference line.

[0025] The term "at least" means no less than or at least. For example, "at least one" can be any quantity, whether it is one or more.

[0026] In some instances, such as when used to describe numerical values, “about” or “approximately” refers to a range within and / or 1%, 5%, or 10% of a value resulting from manufacturing tolerances. For example, a length of about 10 mm means a length of 10 mm within the allowable range of manufacturing tolerances, or in various instances, 10 mm + / - 0.1 mm, + / - 0.5 mm, or + / - 1 mm.

[0027] In some instances, the term "biconcave" refers to a shape that is concave on both sides, such as the two sides of a single opening in a conduit. For example, a biconcave shape can refer to a geometry that includes at least two concave sides (e.g., only two concave sides) that may be opposite each other in some instances. When the shape is projected onto a plane, such as in an elevation view, the sides may be concave.

[0028] In some instances, a "continuous curve" refers to an uninterrupted curve formed along the edge of an opening. In some instances, a continuous curve has a constant radius of curvature. In other instances, a continuous curve has multiple radii of curvature. Alternatively, in some instances, a continuous curve may not contain sharp points, which could be the points where two separate curves intersect within the opening.

[0029] In some instances, the term "distal" refers to the direction toward the patient or tissue site and / or away from the clinician.

[0030] In some instances, the term "elongated body" refers to a structure (e.g., a tubular member) whose length is greater than its width (e.g., the width being a diameter or another cross-sectional dimension, wherein the cross-section is cut in a direction orthogonal to the longitudinal axis of the elongated body). In some instances, the elongated body defines at least one lumen (e.g., one lumen, two lumens, three lumens, or more) configured to receive a fluid, a medical device, or both. The elongated body may contain, for example, a catheter body configured to be at least partially introduced into a patient's vascular system.

[0031] In some instances, "slender biconcave shape" refers to a biconcave shape whose length is greater than its width, wherein, in the case of a side opening, the length of the shape is measured along an axis extending between the proximal and distal ends of the side opening, and the width is measured orthogonally to the axis.

[0032] In some instances, the term "lumen" refers to a cavity, channel, or aperture defined by a structure (e.g., an elongated body or a catheter tip separate from and configured to be mechanically connected to an elongated body). In the case of an elongated body, "lumen" may also be referred to as "body lumen," and in the case of a catheter tip, "lumen" may also be referred to as "tip lumen." The cavity, channel, or aperture may be defined by a surface of the structure. In some instances, "body lumen" may specifically refer to a "first body lumen" and a "second body lumen," or a single body lumen.

[0033] In some instances, the term "proximal" refers to the area away from the patient or tissue or towards the clinician.

[0034] In some instances, a "side opening" of a catheter refers to a through-hole, such as a through-hole extending through the sidewall of the catheter, wherein the opening allows fluid within the catheter to exit the catheter to the external environment or allows fluid to enter the catheter through the sidewall. In some instances, a side opening may specifically refer to a first or second side opening defined by the elongated body of the catheter, wherein the side opening defines a corresponding orifice, gap, or other open space through which fluid can enter or exit a corresponding lumen defined by the elongated body.

[0035] In some instances, the “sidewall” of a catheter refers to the wall of the catheter body, for example, the wall that extends from the proximal end to the distal end of the catheter body and may define the outer and / or inner surfaces of the catheter.

[0036] In the examples described herein, the catheter includes a sidewall defining a side opening in fluid communication with at least one lumen of the catheter. The catheter configuration described herein (including the shape of the side opening) enables efficient flow of fluid into and out of the catheter lumen through the side opening, for example, efficient blood exchange during a hemodialysis procedure. As discussed further in detail below, the side opening has a biconcave shape when the elongated body is straight (e.g., not bent or kinked to skew the shape of the side opening relative to the elongated body being straight). For example, the side opening may each have a concave side on opposite sides of the side opening. A relatively low fluid shear stress can be observed at the side opening when fluid (e.g., blood) flows into and / or out of the catheter lumen through the biconcave side opening. This relatively low fluid shear stress can help minimize or even eliminate adverse effects on fluid flow within the patient's body (e.g., the breakdown of red blood cells in the bloodstream, known as hemolysis).

[0037] In examples of side openings having the biconcave shape described herein (also referred to herein as “biconcave side openings”), the concave side of the side opening may be defined by a side that curves inward toward the side opening axis extending between the proximal and distal ends of the opening. In some instances, the side opening axis may also be referred to as a central axis. For example, some example side openings each have a first side and a second side opposite to the first side, wherein the first and second sides each extend from the proximal end of the respective side opening to the distal end of the respective side opening and curve toward each other between the proximal and distal ends. As an example, the first and second sides may each define a continuous curve that curves toward the other of the first or second sides in a direction toward the midpoint of the respective first or second side and away from the other of the first or second side in a direction away from the midpoint. In some instances, the side of the biconcave shape defining the respective continuous curve (e.g., an uninterrupted curve) has multiple inflection points and multiple radii for changes in curvature.

[0038] In some instances, the biconcave shape can be symmetrical about the side opening axis of the side opening. In other instances, the biconcave shape can be asymmetrical about the side opening axis of the side opening. For example, the concave sides of the side opening can have different radii of curvature from each other.

[0039] In some instances, the catheter includes two side openings that are diametrically opposed to each other, for example, on opposite sides of the central longitudinal axis of the catheter (e.g., the elongated body of the catheter). Each side opening may have a biconcave shape. In some instances, the proximal and distal ends, or both, of the side openings are aligned along the central longitudinal axis of the catheter. In instances where both the proximal and distal ends of the side openings are aligned, the side openings may have axial symmetry. In other instances, neither the proximal nor distal end of the side openings is aligned along the central longitudinal axis of the catheter body. In these instances, and in instances where only the proximal or distal end of the side opening is not aligned along the central longitudinal axis of the catheter, the side openings may have axial asymmetry.

[0040] The biconcave shape of the side opening described in this article typically enables fluid to flow efficiently into and out of the conduit's lumen by providing relatively low pressure drop and low shear stress as fluid flows into or out of the lumen through the side opening. For example, for a conduit with an internal cross-sectional area of ​​3.256 square millimeters (mm²) 2 (venous lumen) and 3.281mm 2 The catheter lumen (within the arterial lumen) and its entry / exit size is 24.183 mm. 2 With a fluid flow rate of approximately 200 mL / min at the side opening, the maximum outer wall shear stress (at the outer surface of the elongated body of the catheter directly adjacent to the side opening) at the biconcave side opening can be from approximately 35 Pa to approximately 39 Pa, and the maximum side wall shear stress (at the surface of the side opening extending between the inner and outer elongated body surfaces) is from approximately 47 Pa to approximately 50 Pa. It is believed that these wall shear stresses, as well as the maximum inner wall shear stress (at the inner surface of the elongated body directly adjacent to the side opening), are lower than the shear wall stresses observed in other catheter side opening shapes, such as side openings of similar size with straight sides rather than concave sides as described herein.

[0041] Furthermore, due to the shape of the side openings and, in some cases, the axial asymmetry between the side openings and / or the orientation of the central axis of the side openings relative to the longitudinal axis of the elongated body of the catheter, the catheter described herein can help reduce recirculation between the two lumens of the catheter during a hemodialysis procedure. Recirculation occurs when purified blood exiting one lumen of the catheter (referred to in some instances as the venous lumen) is directly drawn into the other lumen of the catheter (referred to in some instances as the arterial lumen), causing the purified blood to return to the dialysis device (referred to in some instances as the dialyzer). Recirculation can increase the time required to complete a hemodialysis procedure because blood that has already traveled through the dialyzer may travel through it again, which may be unnecessary for achieving the desired outcome of the hemodialysis procedure. In the examples described herein, at least in part due to the configuration of the side openings (through which blood is introduced into and exits the catheter lumen), the blood flow entering the side opening, which is in fluid communication with the arterial lumen of the catheter, is separated from the blood flow exiting the side opening, which is in fluid communication with the venous lumen, thus minimizing the degree of fluid recirculation. For example, the diametrically opposed positioning of the lateral opening along the distal portion of the catheter and the elongated biconcave shape of the lateral opening can increase the interval between the fluid flow leaving the venous lumen and the fluid flow entering the arterial lumen, which can minimize the degree of recirculation of purified blood between the venous and arterial lumens of the catheter.

[0042] In some instances, in addition to or in lieu of the side opening described herein, the catheter includes an atraumatic distal catheter tip that defines a tip lumen in fluid communication with only one lumen of the catheter. Compared to some existing hemodialysis catheters (which include catheter tips defining multiple lumens in fluid communication with respective lumens of the catheter), this tip configuration can have a smaller volume (e.g., it can be relatively short and / or narrow), which can increase its atraumatic properties and improve catheter navigation through the patient's vascular system to the target site. Additionally, in some instances, the catheter tip shape is configured to improve blood outflow through the lumen in fluid communication with the lumen of the catheter tip compared to catheters with longer and / or wider tips.

[0043] Figure 1 This is a perspective view of an example catheter 10, which includes an inner lumen defined by an elongated body 12. Figure 1 An elongated body 12 (not shown) has at least one side opening 14 in fluid communication. A conduit 10 defines a longitudinal axis A parallel to the longitudinal axis of the elongated body 12, and is therefore interchangeably referred to herein as the longitudinal axis A of the elongated body 12. In some instances, longitudinal axis A is also the central longitudinal axis of the conduit 10 and the elongated body 12. The conduit 10 further includes a hub 16 and a conduit tip 26 located at the proximal end 12A of the elongated body 12.

[0044] Hub 16 is located at the proximal portion of catheter 10 and is configured to fluidly connect one or more lumens defined by catheter 10 to another device, such as a hemodialysis device (e.g., a dialyzer). Hub 16 can be attached to elongated body 12 in any suitable manner, such as by injection molding the body of hub 16 onto elongated body 12 at proximal end 12A. Figure 1 In the example shown, hub 16 includes extension tubes 18, 20 and adapters 22, 24. Each extension tube 18, 20 is in fluid communication with a corresponding lumen of elongated body 12 via an associated fluid passage extending through hub 16. Clinicians can fluidly connect devices, such as hemodialysis devices, to elongated body 12 via extension tubes 18, 20. Adapters 22, 24 can be positioned on the distal ends of extension tubes 18, 20 opposite the ends of extension tubes fixed to hub 16 to facilitate connection of devices to extension tubes 18, 20. For example, adapters 22, 24 may be or otherwise include Luer-lock adapters.

[0045] In some instances, the elongated body 12 may also be referred to as the catheter body. Depending on the type of catheter 10, the elongated body 12 can have any suitable shape (e.g., tubular) and can be made of any suitable material that provides the desired properties, such as, but not limited to, polymers (e.g., polyurethane and / or silicone), and can have any suitable dimensions. The elongated body 12 is flexible and can be formed by any suitable process, such as, but not limited to, injection molding or extrusion. In some instances, the elongated body 12 is substantially straight in its "rest" state (e.g., straight or nearly straight within manufacturing tolerances) when no external force is applied to change its shape. In other instances, the elongated body 12 may have a pre-formed bend to accommodate an internal body cavity or blood vessel into which the elongated body 12 will be positioned. Although this document primarily refers to the elongated body 12 having a circular cross-section (the cross-section being cut in a direction orthogonal to the longitudinal axis A), in other instances, the elongated body 12 can define any suitable cross-sectional shape, such as, but not limited to, elliptical, square, triangular, etc.

[0046] The elongated body 12 can have any suitable size. For example, in some cases, the outer diameter of the elongated body 12 is from about 4 French to about 12 French (where 1 French is 1 / 3 mm), such as about 5 French.

[0047] The elongated body 12 defines one or more lumens configured to receive fluid. The number of lumens may depend on the function of the catheter 10. For example, in some instances where the catheter 10 is intended to be used as a hemodialysis catheter, the elongated body 12 may define two or three lumens. In instances where the elongated body 12 defines two or more lumens, the catheter 10 may be used to simultaneously extract fluid (e.g., blood) from the patient and introduce or return said fluid.

[0048] For example, catheter 10 can be configured to perform hemodialysis, hemodialysis filtration, ultrafiltration, etc., on a patient, wherein toxins are removed from the patient's body. At least one distal portion of catheter 10 can be inserted into the patient's body, and the proximal portion of catheter 10 can be connected to a dialysis unit (e.g., a dialyzer) via extension tubes 18, 20 and adapters 22, 24. Blood can be drawn from the patient's body through an inner lumen (referred to in some instances as an arterial lumen) defined by an elongated body 12 and supplied to a dialysis unit that dialyzes or cleans the blood to remove waste and excess water. Dialyzed blood is returned to the patient through a different inner lumen (referred to in some instances as a venous lumen) defined by the elongated body 12.

[0049] The elongated body 12 includes sidewalls 28 defining one or more side openings 14 through which blood or other fluids can enter or exit the interior of the elongated body 12. Figure 1 In the examples shown (and as...) Figure 5 As better shown below, the elongated body 12 defines two cavities 40, 42. Figure 5 The elongated body 12 has two side openings 14, each of which is in fluid communication with a corresponding cavity 40 and 42. In other embodiments, two or more side openings may be in fluid communication with the same cavity of the elongated body 12, or one of the cavities of the elongated body 12 may be open only at the distal opening at the distal end 12B of the elongated body 12 and may not be open to the outside of the elongated body 12 through the side openings 14 defined by the sidewall 28.

[0050] The elongated body 12 can define any suitable number of side openings 14. Figure 1 In the example shown, the elongated body 12 defines two side openings 14. In other examples, the elongated body 12 may contain only one side opening or three or more side openings. Although this document primarily refers to the dual-lumen catheter 10, in other examples, the elongated body 12 may define only one lumen or more than two lumens (e.g., three lumens), and at least one lumen may be in fluid communication with the outside of the catheter 10 through a corresponding side opening, which may have at least one biconcave shape or another shape according to the examples described herein.

[0051] exist Figure 1 In the illustrated example, the side openings 14 are positioned on different sides of the elongated body 12 such that the two side openings 14 are not circumferentially aligned (only one opening 14 is shown). For example, the side openings 14 may be diametrically opposed to each other and thus positioned on opposite sides of the longitudinal axis A. The side openings 14 may have a suitable alignment with each other along the longitudinal axis A, referred to herein as axial alignment. For example, the proximal end 14A of the side opening 14, the distal end 14B of the side opening 14, or both the proximal end 14A and the distal end 14B of the side opening 14 may be aligned along the longitudinal axis A (referred to herein as "axial alignment" in some examples). In some examples, the proximal end 14A and the distal end 14B of the side opening 14 are longitudinally aligned with each other along the longitudinal axis A, such that the two side openings 14 are axially aligned and have axial symmetry. In other examples, the proximal end 14A and / or the distal end 14B of the side opening 14 are not longitudinally aligned with each other along the longitudinal axis A, such that the side openings 14 have axial asymmetry. In instances where neither the proximal end 14A nor the distal end 14B of the side opening 14 are longitudinally aligned with each other, the side opening 14 may be referred to as being longitudinally offset from each other.

[0052] like Figure 2-4 As shown, each of the side openings 14 is concave on both sides and therefore has a double concave shape. Figure 2 This is a perspective view of the distal portion of catheter 10, showing the distal portion 30 of the elongated body 12 and the catheter tip 26. The distal portion of catheter 10 includes the distal portion of the elongated body 12 and the catheter tip 26, which defines the distal end of catheter 10. Figures 3A-3C yes Figure 2 The side elevation view of the distal portion 30 of the elongated body 12 is shown, and the elongated body 12 is shown in different rotational positions (the axis of rotation is parallel to the longitudinal axis A). Figure 4 The projection of the side opening 14 into the plane is shown, and an example double concave shape is also shown. Figure 1-6 The side openings 14 of the example catheter 10 shown have the same shape and size (e.g., length and width). Therefore, the description of one side opening 14 applies to another side opening 14. In other instances, the side openings 14 may have different shapes and / or different sizes (e.g., different maximum widths and / or different maximum lengths).

[0053] like Figure 2-4As shown, the side opening 14 has a proximal end 14A, a distal end 14B, a first side 34, and a second side 36 opposite to the first side 34. Sides 34 and 36 each extend between the proximal end 14A and the distal end 14B. The proximal end 14A, the distal end 14B, and sides 34 and 36 define the outer periphery of the side opening 14 in the longitudinal direction of the catheter, the side opening itself being physically defined by the sidewall 28 of the elongated body 12. The proximal end 14A may be the distal portion of the side opening 14, and the distal end 14B may be the distal portion of the side opening 14 opposite to the proximal end 14A. The side opening axis 38 ( Figure 3B and 4 The side opening 14 extends between the proximal end 14A and the distal end 14B, for example, intersecting both the proximal end 14A and the distal end 14B. In an example where the side opening axis 38 is parallel to the longitudinal axis A of the elongated body 12 such that the angle α shown in FIG. 3 is 0°, the proximal end 14A is the portion of the side opening 14 closest to the proximal end 12A of the elongated body 12 (e.g., a point), and the distal end 14B is the portion of the side opening 14 closest to the distal end 12B of the elongated body 12 (e.g., a point). That is, in an example where the side opening axis 38 is parallel to the longitudinal axis A of the elongated body 12, the proximal end 14A is the closest side portion of the side opening 14, and the distal end 14B is the farthest side portion of the side opening 14.

[0054] The side opening 14 is skewed relative to the longitudinal axis A of the slender body 12 (e.g., Figure 2-3C As shown in the example), the side opening axis 38 is not parallel to the longitudinal axis A but is transverse to the longitudinal axis A and Figure 3B In examples where the angle α is greater than 0° (where the maximum rotation is equal to 15°), and where the proximal end 14A of the side opening 14 is not the portion of the side opening 14 closest to the proximal end 12A of the elongated body 12 (e.g., a point), and the distal end 14B is not the portion of the side opening 14 closest to the distal end 12B of the elongated body 12 (e.g., a point). Further, in these examples, the proximal end 14A is not aligned with the distal end 14B along an axis parallel to the longitudinal axis A. In some examples, the side opening 14 is oriented relative to the longitudinal axis A such that the side opening axis 38 is at an angle α of approximately 5° to approximately 15°, such as approximately 11° to approximately 15° or approximately 11.2° relative to the longitudinal axis A. The angle α can be selected such that the side opening 14 opens only to one lumen 40 or 42 of the catheter 10 without crossing to open to the other lumen of the catheter.

[0055] The side openings 14 can each be positioned at any suitable distance from the distal end 12B of the elongated body 12. In some instances, the distal end 14B of the side opening is at a distance D from the distal end 12B of the elongated body 12, such as from about 1 mm to about 15 mm, or from about 3 mm to about 10 mm or about 6 mm.

[0056] As discussed above, in some instances, Figure 1-3C In the example shown, the distal ends 14B and / or proximal ends 14A of the two side openings 14 can be aligned. In other examples, for example because... Figure 1-3C In the example shown, the distal ends 14B and / or proximal ends 14A of the two side openings 14 are misaligned, and the side openings 14 are axially displaced from each other. This axial displacement, at least partially along the diameter-opposing side openings 14, can minimize fluid recirculation between the lumens of the catheter 10, as discussed in further detail below.

[0057] like Figure 3C As shown, in some instances, the distal end 14B of one side opening 14 is axially displaced (along the longitudinal axis A) by a distance D from about 1 mm to about 10 mm (e.g., about 2 mm to about 5 mm, or about 3 mm) relative to the distal end 14B of the other side opening. 远侧 Alternatively, in some instances, the proximal end 14A of one side opening 14 is axially displaced (along the longitudinal axis A) by a distance D from about 1 mm to about 10 mm (e.g., about 2 mm to about 5 mm, or about 3 mm) relative to the proximal end 14A of the other side opening. 近侧 Distance D 远侧 and D 近侧 They can be the same in one instance, but different in other instances. At distance D 远侧 and D 近侧 In instances where one or both of the side openings are greater than zero and the side opening 14 is located on the opposite side of the longitudinal axis A, the side opening 14 can be considered to be partially opposite along the diameter.

[0058] Furthermore, in some instances, the distance to D 远侧 and D 近侧 One or both of them are essentially zero (e.g., zero or close to zero within the limits of manufacturing tolerances). At distance D 远侧 and D 近侧 In instances where all values ​​are essentially zero and the side opening 14 is located on the opposite side of the longitudinal axis A, the side opening 14 can be considered to be completely opposite along the diameter.

[0059] like Figure 2-4 As shown, in some instances, the proximal end 14A and the distal end 14B are curved, and these proximal and distal ends may also be referred to as "rounded" ends. Figure 2-4In the example shown, the proximal end 14A has a radius of curvature R. P Furthermore, the distal end 14B has a radius of curvature R. D In some instances, the radius of curvature R P and R D They are essentially equal to each other (e.g., equal to each other within the limits of manufacturing tolerances). In other instances, the radius of curvature R P and R D They differ from each other. In some instances, the radius of curvature R of the proximal end is... P and the radius of curvature R of the distal end D Each is approximately 1 millimeter (mm) to approximately 1.5 mm, such as approximately 1 mm to approximately 1.25 mm or approximately 1.15 mm. In other examples, other radii of curvature may be used for the proximal end 14A and the distal end 14B.

[0060] Sides 34 and 36 of the side opening 14 are curved toward the side opening axis 38 to define the corresponding concave sides of the double concave side opening 14. That is, sides 34 and 36 are each curved toward the side opening axis 38 in directions away from both the proximal end 14A and the distal end 14B of the side opening 14. Sides 34 and 36 may each define a continuous (uninterrupted) curve, for example, as... Figure 2-4 As shown, however, the sides can have different curves including inflection points. In some instances, sides 34 and 36 bend toward each other in a direction toward the midpoint M of the side opening 14, and then bend away from each other in a direction away from the midpoint M. For example, sides 34 and 36 can bend toward each other from the proximal end 14A toward the midpoint M, and then bend away from each other from the midpoint M to the distal end 14B. The midpoint M can be, for example, the longitudinal center of the side opening 14. In these instances, sides 34 and 36 are closest to each other at the midpoint M. In other instances, sides 34 and 36 can be closest to each other at points along the side opening axis 38 other than the midpoint M.

[0061] In some instances, the radii of curvature defined by sides 34 and 36 are approximately the same, making sides 34 and 36 symmetrical about the side opening axis 38. In other instances, sides 34 and 36 have different radii of curvature, making sides 34 and 36 asymmetrical about the side opening axis 38. In some instances, side opening 14 is symmetrical about an axis transverse to the side opening axis 38 (e.g., an axis extending transverse to the side opening axis 38 and passing through the midpoint M). In other instances, such as having different radii of curvature R at the proximal and distal ends, respectively. P and R D In this example, the side opening 14 is asymmetrical about the axis transverse to the side opening axis 38.

[0062] The side opening 14 has any suitable total length L measured along the side opening axis 38 from the proximal end 14A to the distal end 14B. T (Also referred to herein as the maximum length). The total length L of the side opening 14 described herein may be selected based on one or more factors, including but not limited to the following. T And other lengths: the desired fluid flow properties of the catheter 10, the lumen 40, 42 defined by the elongated body 12 Figure 5 The size of the elongated body 12 and its total length (measured along the longitudinal axis A from the proximal end 12A to the distal end 12B). When fluid passes through the body with a longer length L... T When the corresponding side opening is 40 or 42 mm away from the lumen of the catheter, the longer length L T This can help reduce pressure drop. In some instances, the length L of the side opening 14... T Within the range of approximately 5mm to approximately 25mm, such as approximately 10mm to approximately 20mm, or approximately 14mm.

[0063] Sides 34 and 38 of side opening 14 have any suitable length L S The length is less than the length L of the side opening 14. T And it is measured along the axis 38 of the side opening between the proximal end 14A and the distal end 14B. For example, in Figure 4 In the example shown, the lengths of each side, 34 and 38, are the total length L. T Subtract the radius of curvature R of the proximal end 14A P And subtract the radius of curvature R of the distal end 14B. D In other words, it is possible to move along the side opening axis 38 from the radius of curvature R. P The curvature center to the curvature radius R D The curvature center measures the length L of 34 and 38 on each side. S In some instances, the length L of sides 34 and 38 is... S Within the range of approximately 2mm to approximately 23mm, such as approximately 8mm to approximately 16mm, or approximately 12mm.

[0064] Side opening 14 has any suitable maximum width W MAX The maximum width is measured along an axis orthogonal to the side opening axis 38. In some instances, the side opening 14 is widest at the farthest portion of the proximal end 14A and the nearest portion of the distal end 14B, for example, where the ends 14A and 14B begin to bend, and therefore, the maximum width W is... MAX It appears. In some instances, the maximum width W MAX It ranges from about 1mm to about 3mm, such as from about 2mm to about 2.5mm, or about 2.3mm.

[0065] The width of the side opening 14 varies along its length. The side opening 14 defines a minimum width W. MIN The minimum width is measured along an axis orthogonal to the side opening axis 38. As discussed above, sides 34 and 36 curve toward the side opening axis 38, and therefore in some instances, the side opening 14 is narrowest where sides 34 and 36 are closest to each other, and thus has its minimum width W. MIN In some instances, such as when sides 34 and 36 are closest to each other at their respective midpoints (along the side opening axis 38) and the proximal end 14A and distal end 14B have substantially the same radius of curvature (e.g., the same within the limits of manufacturing tolerances), the minimum width W of the side opening is... MIN It appears at the midpoint along the axis 38 of the side opening 38. In some instances, the minimum width W MIN The diameter is approximately 0.2 mm to approximately 2.2 mm, such as approximately 1 mm to approximately 1.5 mm, or approximately 1.2 mm. In other examples, the side opening 14 may have other dimensions. In some examples, for other catheter sizes, the size of the side opening 14 may be increased or decreased proportionally to the diameter of the catheter. For example, if the side opening has a specific width and length for a 12 French catheter (the above is provided for a 12 French catheter), then for a 4 French catheter, the width and length may be scaled at a ratio of 0.3325.

[0066] The biconcave shape of the side opening 14 enables efficient blood exchange during hemodialysis procedures. For example, the shape of the side opening 14 is configured to provide relatively low blood shear stress during blood flow into the lumen of the elongated body 12 through the corresponding side opening 14 and / or during blood flow out of the lumen through the corresponding side opening 14. The shape of the side opening also provides a relatively low pressure drop.

[0067] Furthermore, due to the shape of the side opening 14 and its relative position, the catheter 10 is configured to reduce recirculation between the arterial lumen and the venous lumen defined by the elongated body 12. As discussed above, during a hemodialysis procedure, when purified blood leaving the venous lumen of the catheter is directly drawn into the arterial lumen, causing the purified blood to return to the dialyzer, recirculation occurs. Thus, recirculation increases the time required to complete the hemodialysis procedure. Because in Figure 2In the example shown in -3, the asymmetrical configuration of the side opening 14 separates the blood flow entering the side opening, which is in fluid communication with the arterial lumen of the catheter, from the blood flow leaving the side opening, which is in fluid communication with the venous lumen, thereby minimizing the degree of fluid recirculation. For example, the diametrically opposed positioning of at least a portion of the side opening 14, the elongated shape of the side opening 14, and the orientation of the side opening axis 38 transverse to the longitudinal axis A can increase the interval between the fluid flow leaving the venous lumen and the fluid flow entering the arterial lumen, thereby minimizing the degree of recirculation of purified blood between the venous and arterial lumen of the catheter.

[0068] Figure 5 This is a schematic cross-sectional view of the distal portion 30 of catheter 10, wherein the cross-section is along the central longitudinal axis A of catheter 10. Figure 3A The line in the middle is cut off at point 5-5. For example... Figure 5 As shown, the elongated body 12 defines at least one internal cavity. Figure 5 The cavities shown are two cavities 40 and 42, each in fluid communication with at least one side opening 14, allowing fluid from at least one cavity to enter and exit the elongated body 12. In some instances where the elongated body 12 includes two or more cavities, the elongated body 12 may define or otherwise include a diaphragm 44 extending along the length of the elongated body 12 and defining at least a portion of two or more cavities. Figure 5 In the example shown, the diaphragm 44, together with the sidewall 28, defines the lumens 40 and 42. In other examples, as discussed above, the catheter 10 may have a single lumen or more than two lumens. For example, the elongated body 12 may define a third lumen for receiving a guidewire, etc.

[0069] Lumens 40 and 42 each define a fluid conduit for conduit 10. In some embodiments, lumens 40 and 42 each extend from a proximal end 12A of the elongated body 12 through the elongated body 12 to a distal end 12B and terminate at the distal end 12B. Fluid access to lumens 40 and 42 can be made via hub 16 at the proximal portion of conduit 10. For example, when hub 16 is properly connected to elongated body 12, lumen 40 can be in fluid communication with extension tube 20 and adapter 24, and lumen 42 can be in fluid communication with extension tube 18 and adapter 22.

[0070] The side opening 14 is configured to allow fluid flows F, F' to travel between the external environment of the elongated body 12 (such as a patient's vascular system or other hollow anatomical structures) and the lumens 40, 42 of the elongated body 12. The side opening 14 may have contoured edges, formed, for example by laser cutting, molding together with the elongated body 12, and / or otherwise smoothed to minimize blood flow interruption (or hemolysis) and thrombosis. The contoured edges may, for example, be located at the junction between the outer surface 46 of the elongated body 12 and the side surface 48 defining the side opening 14, wherein the side surface 48 extends between the outer surface 46 and the inner surface 50 of the elongated body 12. The inner surface 50 may define, for example, at least a portion of the lumens 40, 42.

[0071] Due to the configuration of the elongated body 12, either of the lumens 40, 42 can be used as an arterial lumen or a venous lumen during a hemodialysis procedure. Therefore, the catheter 10 can be a reversible hemodialysis catheter. Fluid can flow out through one lumen 40 or 42 in one axial direction and through the other lumen 42 or 40 in the opposite axial direction. The separation of blood flow F' entering the side opening 14 fluidly communicating with lumen 42 (but not with lumen 40) and blood flow F exiting the side opening 14 fluidly communicating with the other lumen 40 (but not with lumen 42) minimizes the degree of fluid recirculation. That is, the outer surface 46 of the elongated body 12 provides a gap between the two side openings 14 that substantially minimizes the migration of fluid flow F exiting the lumen 40, which acts as an artery, towards the fluid flow F' entering the lumen 42, which acts as a venous lumen.

[0072] The cavities 40, 42 can have any suitable cross-sectional shape and size, which provides the desired fluid flow characteristics through the cavities. In some instances, the cavities 40, 42 can comprise rectangular, kidney-shaped, and / or D-shaped cross-sectional configurations.

[0073] Figure 6 This is a schematic cross-sectional view of the elongated body 12, wherein the cross-section is along... Figure 3A Line 6-6 in the diagram is intercepted in a direction orthogonal to the vertical axis A. Figure 6 In the example shown, the cavity 42 has a kidney-shaped cross-section, and the cavity 40 has a shape created by the kidney shape occupying the circular cross-section. Figure 6 The diagram also shows an inner lumen 60 defined by a catheter tip 26, which is shown in the following reference. Figure 7 and Figure 10-12Further detailed description. In other examples, the cavities 40 and 42 may each have different cross-sectional shapes. For example, one or both cavities of cavities 40 and 42 may have a "D" shaped cross-section (e.g., defined by the corresponding longitudinal half of the elongated body 12), a "C" shaped cross-section, a kidney-shaped cross-section, a circular cross-section, a polygonal cross-section, etc.

[0074] although Figure 2-3C Figures 5 and 6 illustrate an example catheter 10 containing lateral openings 14 that are diametrically opposed, but in other instances, the lateral openings of the catheter are not diametrically opposed (e.g., extending together along the longitudinal axis A), but are completely longitudinally displaced from each other. Figure 8 This is another example side elevation view of the distal portion 80 of the slender body of the catheter, the figure being... Figure 1 An example of the elongated body 12 and the conduit 10 is shown. Therefore, Figure 8 The slender body shown will be referred to as slender body 12. Figure 9 yes Figure 8 A schematic cross-sectional view of the distal portion of the catheter, wherein the cross-section is in relation to... Figure 8 The image shown was cropped from a plane parallel to it. Figure 9 The catheter tip 26 is also shown, for example, as in the reference. Figure 5 A similar cross-sectional view is described.

[0075] exist Figure 8 and 9 In the example shown, the elongated body 12 defines side openings 82 and 84, which are identical to side opening 14 except that they are located on opposite sides of the longitudinal axis A. Therefore, Figure 8 The side openings 82 and 84 shown are similar in shape to Figure 1-6 The side openings 14 are the same, but the side openings 82 and 84 are not opposite each other along the diameter, but are completely longitudinally shifted from each other. That is to say, with Figure 1-6 Compared to side opening 14, side openings 82 and 84 do not extend together along the longitudinal axis A of the elongated body 12. The proximal end 82A of side opening 82 and the distal end 84B of side opening 84 are separated by a distance D. 分隔 The distance is measured along the vertical axis A. In some instances, the distance D... 分隔 It ranges from about 1mm to about 25mm, such as from about 5mm to about 10mm, or about 2mm.

[0076] Axial separation distance D between side openings 82 and 84 分隔 This facilitates the axial displacement (distance D) between the distal end 82B of the side opening 82 and the distal end 84B of the side opening 84. 远侧) and the axial displacement (distance D) between the proximal end 82A of the side opening 82 and the proximal end 84A of the side opening 84. 近侧 In some instances of the distal portion 80, the distance D 远侧 The distance is approximately 15mm to approximately 39mm, such as approximately 15mm to approximately 20mm, or approximately 16mm, and the distance from D is... 近侧 It ranges from approximately 15mm to approximately 39mm, such as from approximately 15mm to approximately 20mm, or approximately 16mm.

[0077] like Figure 8 and 9 As shown, the side openings 82 and 84 are completely longitudinally displaced from each other and do not overlap along the longitudinal axis A, thereby increasing the interval between the fluid flow F entering the lumen 42 and the fluid flow F' exiting the lumen 40. This minimizes the degree of recirculation of purified blood between the venous and arterial lumen of the catheter 10 during hemodialysis. Therefore, the non-diameter-opposite positioning of the side openings 82 and 84 and their biconcave shape help separate the fluid flow F exiting the venous lumen from the fluid flow F' entering the arterial lumen, which can lead to better treatment outcomes or at least shorten the duration of dialysis sessions.

[0078] like Figure 1-3B as well as Figure 6 , 7 As shown in Figures 9-12, in some instances, catheter 10 includes a catheter tip 26 located at the distal end 12B of the elongated body 12. Figure 7 This is an end view of the catheter tip 26, viewed from the direction of the proximal end 62 of the catheter tip 26, at the distal end 64 of the catheter tip 26. Figure 10 This is an exploded perspective view of the distal portion 30 of the catheter 10, showing the catheter tip 26 aligned with but not mechanically connected to the elongated body 12. Figure 11 This is a side elevation view of the catheter tip 26.

[0079] The catheter tip 26 defines the most distal portion of the catheter 10, and therefore, the catheter tip can be configured to assist in the insertion of the catheter 10 into a patient. For example, the outer surface 66 of the catheter tip 26 tapers distally to facilitate insertion of the catheter 10 into the patient's vascular system or another hollow anatomical structure. While the distal end 64 of the catheter tip 26 is shown to have a rounded, blunt shape, other shapes and profiles of the distal end 64 may also be used. In some instances, the distal end 64 has a relatively non-invasive profile, for example, defined by a distal tapered portion and a rounded distal end 64.

[0080] The outer surface 66 of the catheter tip 26 and the outer surface 46 of the elongated body 12 can have a similar configuration such that when the catheter tip 26 and the elongated body 12 are properly assembled, the junction between the catheter tip 26 and the elongated body 12 is relatively smooth (e.g., having a substantially uniform outer periphery, such as substantially the same outer diameter). This relatively smooth transition between the catheter tip 26 and the elongated body 12 can help reduce the likelihood of thrombus formation due to blood flow through the junction and can also help provide a smoother surface for engagement with patient tissue.

[0081] The catheter tip 26 may be made of a material suitable for medical applications, including, for example, polymers, silicones, and / or polyurethanes. Additionally, the catheter tip 26 may be made of the same or a different material as the elongated body 12. In some instances, the catheter tip 26 is formed separately from the elongated body 12 and is attached to a distal portion of the elongated body 12, such as the distal end 12B of the elongated body 12. In other instances, the catheter tip 26 is formed integrally or integrally with the elongated body 12. At least the distal portion of the elongated body 12 and the proximal portion of the catheter tip 26 have substantially similar external dimensions to provide a smooth transition between the elongated body 12 and the catheter tip 26.

[0082] The catheter tip 26 defines an inner lumen 60 that extends from a proximal end 62 to a distal end 64 of the catheter tip 26. (As...) Figure 11 As shown, the lumen 60 terminates at the distal opening 67 at the distal end 64 of the catheter tip 26. The distal opening 67 may be the distal opening of the catheter 10. In some instances, when the elongated body 12 and the catheter tip 26 are correctly assembled, the lumen 60 of the catheter tip 26 is in fluid communication and aligned with only one lumen 40, 42 of the elongated body 12. In the example shown in the figure, when the elongated body 12 and the catheter tip 26 are correctly assembled, the lumen 60 of the catheter tip 26 is in fluid communication with the lumen 40 of the elongated body 12. In these instances, the lumen 42 of the elongated body 12 is not in fluid communication with any lumen (including lumen 60) of the catheter tip 26. Therefore, the catheter 10 is configured such that fluid drawn from the lumen 42 via the hub 16 can only enter the lumen 42 through the corresponding side opening 14, and fluid can only enter the lumen 42 through the corresponding side opening 14 at the distal portion 30 of the elongated body 12.

[0083] Because the catheter tip 26 defines fewer lumens than the elongated body 12 (e.g., only one lumen, while the elongated body defines two or more lumens), the total volume of space occupied by the catheter tip 26 and the shape of the catheter tip 26 can be relatively small, especially compared to instances where the catheter tip 26 defines the same number of lumens as the elongated body 12 and / or instances where the catheter tip 26 defines two lumens, without adversely affecting fluid flow through the catheter 10. For example, the external cross-sectional dimension of the distal portion of the catheter tip 26 is smaller than the external cross-sectional dimension of the distal portion of the elongated body 12 (e.g., at the distal end 12B), which is cut in a direction orthogonal to the longitudinal axis A of the catheter 10. In instances where the elongated body 12 is tubular and the catheter tip 26 defines a tubular distal portion, the cross-sectional dimension can be diameter. In these instances, due to the distal taper of the catheter tip 26, such as... Figure 11 As shown, the catheter tip 26 can be defined as a circular (asymmetrical) cone or another asymmetrical shape (where the line of symmetry is the longitudinal axis A of the catheter 10).

[0084] When introducing catheter 10 into a patient or otherwise navigating through the patient's vascular system, the distal tapered portion of catheter tip 26 can help minimize the invasiveness of catheter 10, for example, by reducing adverse interactions with patient tissues. In some instances, at the proximal portion of catheter tip 26, the distal tapered portion is at least partially defined by a compound radius of curvature. For example, at least the proximal portion of catheter tip 26 on the side having the connecting member 70 (described below) can define a plurality of radii of curvature R. B R C and R D In some instances, the radius of curvature R B The radius of curvature is approximately 15mm to 20mm, such as approximately 18mm, with a radius of curvature R. C It ranges from approximately 1 mm to approximately 5 mm, such as approximately 2.55 mm, and the radius of curvature R D It ranges from approximately 8mm to approximately 15mm, such as approximately 11.5mm.

[0085] In other examples, the catheter tip 26 may define two or more lumens, and each catheter tip lumen may be in fluid communication with the same or corresponding lumens 40, 42 of the elongated body 12. In some of these examples, the catheter tip 26 may have a greater than Figure 10 and 11 The shapes shown are more symmetrical shapes, such as substantially symmetrical shapes (e.g., symmetrical within the limits of manufacturing tolerances).

[0086] In some instances, the catheter tip 26 defines an atraumatic distal end 64, which is curved to help reduce any adverse interactions with patient tissues when the catheter 10 is introduced into the patient or otherwise navigated through the patient's vascular system. In some instances, the distal end 64 has a radius of curvature R of about 0.25 mm to about 1 mm, such as about 0.60 mm. A .

[0087] Any suitable technique can be used to mechanically and fluidly connect the catheter tip 26 to the elongated body 12. In some instances, the catheter tip 26 and the elongated body 12 are connected via a mating joint, with the proximal end 62 of the catheter tip positioned directly adjacent to the distal end 12B of the elongated body 12. In some instances, the catheter tip 26 and the elongated body 12 are connected via a mating portion. For example, as... Figure 10 and 11 As shown, in some instances, the catheter tip 26 includes or is otherwise connected to a pair of proximal extending connecting members 68, 70, which are configured to be inserted into the lumens 40, 42 of the elongated body 12 during assembly (and mechanical connection) of the elongated body 12 and the catheter tip 26. Thus, in some instances, the connecting members 68, 70 can have various shapes corresponding to and configured to be received within and mate with the lumens 40, 42. For example, in Figure 10 and 11 In the example shown, the connecting member 68 is configured to be housed in the lumen 40 and thus has an elliptical (e.g., pointed elliptical or lenticular) cross-sectional shape, and the connecting member 70 is configured to be housed in the lumen 42 and thus has a kidney-shaped cross-sectional shape, the cross-section being cut in a direction orthogonal to the longitudinal axis of the catheter tip 26, which can be parallel to the longitudinal axis A of the catheter 10 when the catheter tip 26 is properly assembled with the elongated body 12.

[0088] The connecting members 68 and 70 are spaced apart to define a space in which the diaphragm 44 of the elongated body 12 can be housed. In instances where the lumen 60 of the catheter tip 26 is in fluid communication with the lumen 40 of the elongated body 12 when the elongated body 12 and the catheter tip 26 are properly assembled, and the lumen 42 of the elongated body 12 is not in fluid communication with any lumen of the catheter tip 26, the connecting member 68 may define a channel 72 configured to fluidly connect the lumen 60 of the catheter tip 26 with the lumen 40 of the elongated body 12. Additionally, in these instances, the connecting member 70 may be configured to fit within the lumen 42 of the elongated body 12, which may facilitate alignment of the catheter tip 26 and the elongated body 12 during catheter 10 assembly. In some instances, the connecting member 70 may be configured to partially or completely block or otherwise obstruct the lumen 42 in order to provide a fluid-impermeable seal between the catheter tip 26 and the elongated body 12, and to help prevent fluid leakage from the lumen 42 at the distal end 12B of the elongated body 12 (e.g., at the interface between the catheter tip 26 and the elongated body 12).

[0089] In an instance where the catheter tip 26 defines a plurality of cavities configured to be in fluid communication with a corresponding cavity among the cavities 40, 42 of the elongated body 12 when the elongated body 12 and the catheter tip 26 are properly assembled, two connecting members 68, 70 may define corresponding channels 72 configured to fluidly connect the cavity of the catheter tip 26 to the corresponding cavity 40, 42 of the elongated body 12.

[0090] In any of the examples described herein, connecting members 68, 70 may engage the elongated body cavities 40, 42 with an interference fit or a friction fit, thereby forming a substantially fluid-impermeable seal with the cavities 40, 42. Alternatively or additionally, connecting members 68, 70 may be secured within the cavities 40, 42 using chemical adhesives or mechanical connections (such as by welding).

[0091] Connecting members 68 and 70 can have any suitable length (measured along the longitudinal axis A of the conduit 10). For example, although connecting member 68 is shown as having a shorter length than connecting member 70, in other instances, connecting member 68 can be longer than connecting member 70. Furthermore, although in Figure 10 and 11 The diagram shows connecting members 68 and 70 with different lengths, but in other instances, connecting members 68 and 70 may have substantially the same length (e.g., the same length as allowed by manufacturing tolerances).

[0092] Figure 12 This is an end view of catheter tip 26, and it shows the relationship between catheter tip 26 and... Figure 6 The ends shown are opposite each other. For example... Figure 12As shown. For depth perception, the portion of the catheter tip 26 away from the connecting members 68, 70 is shown with cross-hatching.

[0093] While example catheters are discussed in relation to medical catheters used for fluid administration, and more specifically, hemodialysis catheters, the catheters described herein can be used in a range of applications, including other surgical, diagnostic, and related treatments for a subject's disease and physical discomfort. Example applications of the catheters described herein include hemodialysis applications, cardiac applications, abdominal applications, urinary applications, bowel applications, chronic applications, and / or acute applications.

[0094] Example

[0095] A first conduit containing two side openings, each having a biconcave shape (e.g., ... Figure 1-5 The fluid flow characteristics of the first conduit (shown) are compared with those of a second conduit containing two side openings with parallel sides rather than concave sides. The side openings of the first and second conduits have similar lengths and maximum widths. The side openings of the first conduit are partially diametrically opposed (e.g., as shown). Figure 3A As shown), the side openings of the second conduit are completely opposite along the diameter, thus defining a symmetrical arrangement of the side openings, with the line of symmetry being the longitudinal axis of the second conduit. The first and second conduits each define two D-shaped lumens, one of which is in fluid communication with the corresponding side opening.

[0096] The flow of blood through the lumens of the first and second conduits (in the direction of inflow and outflow relative to the side openings) and into or out of the corresponding side openings was simulated using ANSYS 2019R2 simulation software, available from Ansys Inc. of Canonsburg, Pennsylvania. Specifically, the ANSYS CFX computational fluid dynamics tool, the ANSYS SpaceClaim 3D modeling application, and the ANSYS Meshing software were used to perform the fluid flow simulation. The average size of the mesh elements was 1e-4m.

[0097] In addition to the residence time distribution (RTD) analysis described below, steady-state analysis was performed to determine the fluid flow parameters of the first and second catheters. The following blood flow scheme was used for simulation: a non-Newtonian fluid from the Carreau-Yasuda viscosity model, and an incompressible fluid density function of plasma and blood cell specific volumes (Hct = 40% → average blood density = 1051 kg / m³). 3The relative pressure range was 4 mmHg, which is a typical average value in the right atrium during the diastolic phase of a cardiac cycle in some patients; buoyancy effects were not considered, taking into account the multiple positions that can be set for the patient during the blood processing procedure. Additionally, an inlet / outlet flow rate of 200 mL / min through the catheter lumen was used, an inlet superior vena cava (SVC) flow rate of 2000 mL / min was used, and an outlet SVC opening condition with a relative pressure of 0 Pascals (Pa) was used. For RTD analysis, a diffusion rate of 1e-18 m was used. 2 / s of passive tracer.

[0098] The outer diameter of the first catheter is 3.9878 mm (12 French catheter), and the area of ​​each side opening is 24.183 mm². 2 The first catheter is defined as having a diameter of 3.256 mm. 2 The cross-sectional area of ​​the vein lumen is 3.281 mm. 2 The arterial lumen has a cross-sectional area, the cross-section being cut in a direction orthogonal to the longitudinal axis of the first catheter. The first catheter includes a catheter tip coupled to an elongated body (which defines both the venous and arterial lumen), and the catheter tip defines fluid communication with the arterial lumen and has a diameter of 0.893 mm. 2 The tip cavity has a cross-sectional area and a diameter of 1.066 mm, the cross-section being cut in a direction orthogonal to the longitudinal axis of the first conduit.

[0099] The second catheter has an outer diameter of 3.988 mm (12 French catheter), and each side opening has an area of ​​20.811 mm². 2 The second catheter is defined as having a diameter of 3.211 mm. 2 The cross-sectional area of ​​the vein lumen and its diameter are 3.211 mm. 2 The arterial lumen has a cross-sectional area, the cross-section of which is cut in a direction orthogonal to the longitudinal axis of the second catheter. The second catheter includes a catheter tip coupled to an elongated body (which defines both the venous and arterial lumen), and the catheter tip defines fluid communication with the arterial lumen and has a diameter of 0.894 mm. 2 The tip cavity has a cross-sectional area and a diameter of 1.067 mm, the cross-section being cut in a direction orthogonal to the longitudinal axis of the second conduit.

[0100] The software described above was used to simulate fluid flow exiting the corresponding venous lumen of each catheter and entering the corresponding arterial lumen. The simulations showed that for the second catheter, the maximum external wall shear stress at the distal end of the lateral opening was 48.8 Pa, while for the first catheter, the maximum external wall shear stress at the distal end of the lateral opening was 38.06 Pa. For catheters with D-shaped or kidney-shaped lumens (e.g., as...), the simulations also showed... Figure 6 The first catheter (shown as an example) instead of having two D-shaped lumens, has a maximum external wall shear stress of 35.70 Pa at the distal end of its side opening. The maximum external wall shear stress is the shear stress measured (by simulation) at the outer-facing wall of the corresponding catheter. It is believed that the biconcave shape of the side opening of the first catheter contributes to a 22% or 27% reduction in external wall shear stress compared to the first catheter without the biconcave side opening. As discussed above, reduced shear stress is likely desirable because lower shear stress may result in less hemolysis during dialysis.

[0101] Simulations also show that for the second catheter, the maximum sidewall shear stress near the proximal end of the side opening is 140.34 Pa, while for the first catheter, the maximum sidewall shear stress near the proximal end of the side opening is 49.32 Pa. For another first catheter with a D-shaped lumen and a kidney-shaped lumen, the maximum sidewall shear stress near the proximal end of the side opening is 47.20 Pa. The maximum sidewall shear stress is measured on the side surface defining the side opening (e.g., corresponding to...). Figure 5 The shear stress was measured (by simulation) at the side surface 48 shown in the diagram. It is believed that the biconcave shape of the side opening of the first catheter helps to reduce the maximum sidewall shear stress by 65% ​​or 68% compared to the first catheter which does not contain a biconcave side opening. Simulations also show that the biconcave shape of the side opening of the first catheter can reduce the maximum sidewall shear stress near the distal end of the side opening by 16% or 18% compared to the first catheter.

[0102] Simulations show that, relative to the second catheter, the first catheter exhibits a slight increase (approximately 4% to approximately 9%) in maximum inner wall shear stress at the proximal end of the lateral opening. Maximum inner wall shear stress is the shear stress measured (by simulation) at the inward-facing wall of the respective catheter.

[0103] To determine the effect of the biconcave side opening on blood recirculation, the residence time distribution of the first and second catheters was simulated. For the residence time distribution simulation, a pulsed injection method (injection time of 0.05 seconds) was used, and the diffusion coefficient was negligible (1e-18m). 2 A passive tracer ( / s) was used to detect recirculation. Transient analysis was performed on the tracer. It was found that the first catheter, containing a biconcave side opening, reduced the amount of recirculation compared to that observed with the second catheter. Specifically, the recirculation percentage for the second catheter was determined to be 0.000000043%, while for the first catheter, the recirculation percentage was determined to be 0.00000000016% or 0.00000000031%. Simulations showed that the first catheter could reduce recirculation by 99.62% or 99.28% compared to the second catheter.

[0104] Example 1: In some examples, a catheter includes an elongated body defining a body lumen, wherein the elongated body includes a sidewall defining a side opening in fluid communication with the body lumen, the side opening having a biconcave shape when the elongated body is straight.

[0105] Example 2: In some examples of the catheter described in Example 1, the side opening has a proximal end, a distal end, a first side extending from the proximal end to the distal end, and a second side opposite to the first side and extending from the proximal end to the distal end, wherein when the elongated body is straight, the first side and the second side bend toward each other between the proximal end and the distal end.

[0106] Example 3: In some instances of the catheter described in Example 2, the proximal end and the distal end are not aligned along an axis parallel to the longitudinal axis of the elongated body.

[0107] Example 4: In some examples of the catheter described in Example 2 or Example 3, the side opening defines a side opening axis that intersects the proximal end and the distal end, wherein the first side and the second side each define a curve that bends inward toward the side opening axis.

[0108] Example 5: In some examples of the catheter described in Example 4, the curve is closest to the axis of the lateral opening at the midpoint of the corresponding first or second side.

[0109] Example 6: In some examples of the catheters described in any one of Examples 1 to 5, the side opening is defined by a side opening axis extending between the proximal end and the distal end of the side opening and a transverse axis transverse to the side opening axis, and wherein the side opening is symmetrical about the transverse axis.

[0110] Example 7: In some examples of the catheters described in any one of Examples 1 to 6, the side opening defines a circular proximal end and a circular distal end.

[0111] Example 8: In some examples of the catheter in any one of Examples 1 to 7, the lumen is a first body lumen and the side opening is a first side opening, the elongated body further defining a second body lumen, wherein the sidewall of the elongated body defines a second side opening in fluid communication with the second body lumen.

[0112] Example 9: In some examples of the catheters described in any one of Examples 1 to 8, the first side opening and the second side opening have the same shape.

[0113] Example 10: In some examples of the catheters described in any one of Examples 1 to 9, the first side opening and the second side opening are diametrically opposed.

[0114] Example 11: In some examples of the catheters described in any one of Examples 1 to 10, the proximal end of the first side opening is not aligned with the proximal end of the second side opening along the longitudinal axis of the elongated body.

[0115] Example 12: In some examples of the catheters described in any one of Examples 1 to 11, the catheter further includes a tapered catheter tip located at the distal end of the elongated body, wherein the tapered catheter tip defines a tip lumen in fluid communication with the lumen of the body.

[0116] Example 13: In some examples of the catheter described in Example 12, the lumen is a first body lumen and the side opening is a first side opening, the elongated body further defines a second body lumen, wherein the sidewall defines a second side opening in fluid communication with the second body lumen, and wherein the tapered catheter tip does not define a lumen in fluid communication with the second body lumen.

[0117] Example 14: In some examples of the catheters described in Example 12 or 13, the tip of the tapered catheter is asymmetrical about the longitudinal axis of the catheter.

[0118] Example 15: In some examples of the catheters described in any one of Examples 12 to 14, the tip of the tapered catheter is separated from and fixed to the distal portion of the elongated body.

[0119] Example 16: In some examples of the catheters described in any one of Examples 12 to 14, the tapered catheter tip is integrally formed with the elongated body.

[0120] Example 17: In some examples, a catheter includes an elongated body defining a body lumen, wherein the elongated body includes a sidewall defining a side opening in fluid communication with the body lumen, the side opening having a proximal end, a distal end, a first side extending from the proximal end to the distal end, and a second side opposite to the first side and extending from the proximal end to the distal end, wherein when the elongated body is straight, the first side and the second side bend toward each other between the proximal end and the distal end, and wherein the proximal end and the distal end are not aligned along an axis parallel to the longitudinal axis of the elongated body.

[0121] Example 18: In some examples of the catheter described in Example 17, the first side and the second side bend toward each other between the proximal end and the distal end to define a biconcave shape.

[0122] Example 19: In some examples of the catheter described in Example 17 or 18, the proximal end and the distal end of the side opening are not aligned along the axis parallel to the longitudinal axis of the elongated body.

[0123] Example 20: In some examples of the catheters described in any one of Examples 17 to 19, the proximal end of the side opening is circumferentially offset from the distal end of the side opening.

[0124] Example 21: In some examples of the catheters described in any one of Examples 17 to 20, the side opening defines a circular proximal end and a circular distal end.

[0125] Example 22: In some examples of the catheter in any one of Examples 17 to 21, the lumen is a first body lumen and the side opening is a first side opening, the elongated body further defining a second body lumen, wherein the sidewall defines a second side opening in fluid communication with the second body lumen.

[0126] Example 23: In some instances of the catheter described in Example 22, the first side opening and the second side opening have the same shape.

[0127] Example 24: In some examples of the catheter in Example 22 or any one of 22, the first side opening and the second side opening are diametrically opposed.

[0128] Example 25: In some examples of the catheters described in any one of Examples 22 to 24, the proximal end of the first side opening is not aligned with the proximal end of the second side opening along the longitudinal axis of the elongated body.

[0129] Example 26: In some examples of the catheter described in any one of Examples 17 to 25, the catheter further includes a tapered catheter tip located at the distal end of the elongated body, wherein the tapered catheter tip defines a tip lumen in fluid communication with the lumen of the body.

[0130] Example 27: In some examples of the catheter described in Example 26, the lumen is a first body lumen and the side opening is a first side opening, the elongated body further defines a second body lumen, wherein the sidewall defines a second side opening in fluid communication with the second body lumen, and wherein the tapered catheter tip does not define a lumen in fluid communication with the second body lumen.

[0131] Example 28: In some examples of the catheters described in Example 26 or 27, the tip of the tapered catheter is asymmetrical about the longitudinal axis of the catheter.

[0132] Example 29: In some examples, a catheter includes an elongated body defining a body lumen, wherein the elongated body includes a sidewall defining a side opening in fluid communication with the body lumen, the side opening having a proximal end, a distal end, a first side extending from the proximal end to the distal end, and a second side opposite to the first side and extending from the proximal end to the distal end, wherein each of the first side and the second side defines a continuous curve that curves toward the other of the first side or the second side in a direction toward the midpoint of the respective first side or second side.

[0133] Example 30: In some examples of the catheter described in Example 29, the first side and the second side bend toward each other between the proximal end and the distal end of the lateral opening to define a biconcave shape.

[0134] Example 31: In some examples of the catheter described in Examples 29 or 30, the proximal and distal ends of the side opening are not aligned along an axis parallel to the longitudinal axis of the elongated body.

[0135] Example 32: In some examples of the catheters described in any one of Examples 29 to 31, the proximal end of the side opening is circumferentially offset from the distal end of the side opening.

[0136] Example 33: In some examples of the catheters described in any one of Examples 29 to 32, the side opening defines a circular proximal end and a circular distal end.

[0137] Example 34: In some examples of the catheter described in any one of Examples 29 to 33, the lumen is a first body lumen and the side opening is a first side opening, the elongated body further defining a second body lumen, wherein the sidewall defines a second side opening in fluid communication with the second body lumen.

[0138] Example 35: In some instances of the catheter described in Example 34, the first side opening and the second side opening have the same shape.

[0139] Example 36: In some examples of the catheter described in Example 34 or 35, the first side opening and the second side opening are diametrically opposed.

[0140] Example 37: In some examples of the catheters described in any one of Examples 34 to 36, the proximal end of the first side opening is not aligned with the proximal end of the second side opening along the longitudinal axis of the elongated body.

[0141] Example 38: In some examples of the catheter described in any one of Examples 29 to 37, the catheter further includes a tapered catheter tip located at the distal end of the elongated body, wherein the tapered catheter tip defines a tip lumen in fluid communication with the lumen of the body.

[0142] Example 39: In some examples of the catheter described in Example 38, the lumen is a first body lumen and the side opening is a first side opening, the elongated body further defines a second body lumen, wherein the sidewall defines a second side opening in fluid communication with the second body lumen, and wherein the tapered catheter tip does not define a lumen in fluid communication with the second body lumen.

[0143] Example 40: In some instances of the catheters described in Example 38 or Example 39, the tip of the tapered catheter is asymmetrical about the longitudinal axis of the catheter.

[0144] Example 41: A method of using any of the catheters described in Examples 1 to 40.

[0145] Example 42: A method for manufacturing any one of the catheters described in Examples 1 to 40.

[0146] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

1. A catheter comprising: An elongated body defining a first body cavity and a second body cavity, wherein the elongated body includes sidewalls defining a first side opening and a second side opening respectively in fluid communication with the first body cavity and the second body cavity, the first side opening and the second side opening each having a proximal end, a distal end, a first side extending from the proximal end to the distal end, and a second side opposite to the first side and extending from the proximal end to the distal end, wherein each of the first side and the second side defines a continuous curve that curves toward the other of the first side or the second side in a direction toward the midpoint of the respective first side or the second side, wherein the first side opening and the second side opening are completely longitudinally displaced from each other and do not overlap along the longitudinal axis of the elongated body. When the shapes of the first and second side openings are projected onto a plane, the first and second sides are concave. The first side and the second side curve toward each other between the proximal and distal ends of the openings on the first and second sides to define a double concave shape. The edges of the first and second side openings do not contain any sharp points. The proximal and distal ends of the first and second side openings are not aligned along an axis parallel to the longitudinal axis of the elongated body. The proximal ends of the first side opening and the second side opening are circumferentially offset from the distal ends of the corresponding first side opening and the second side opening.

2. The catheter of claim 1, wherein the first side opening and the second side opening each define a circular proximal end and a circular distal end.

3. The catheter according to claim 1, wherein the first side opening and the second side opening have the same shape.

4. The catheter of claim 1, wherein the first side opening and the second side opening are each defined by a side opening axis extending between the proximal and distal ends of the respective first side opening and the second side opening, and a transverse axis transverse to the side opening axis, and wherein the first side opening and the second side opening are each symmetrical about the transverse axis.

5. The catheter of claim 1, further comprising a tapered catheter tip located at the distal end of the elongated body, wherein the tapered catheter tip defines a tip lumen in fluid communication with the lumen of the first body.

6. The catheter of claim 5, wherein the tapered catheter tip does not define an inner cavity in fluid communication with the inner cavity of the second body.

7. The catheter according to claim 5 or claim 6, wherein the tapered catheter tip is asymmetrical about the longitudinal axis of the catheter.

8. The catheter according to any one of claims 5 to 6, wherein the tapered catheter tip is separated from and fixed to the distal portion of the elongated body.

9. The catheter according to any one of claims 5 to 6, wherein the tapered catheter tip is integrally formed with the elongated body.

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