Vascular Access Catheters

Abstract

A vascular access catheter includes an elongated tubular catheter body surrounding a lumen. The catheter body includes a catheter tip terminating at a distal end of the catheter and including a distal edge at the distal end of the catheter surrounding an opening leading to the lumen. The distal edge includes a leading edge spanning the top of the opening and a beveled edge spanning the bottom of the opening and sloping proximally away from the leading edge relative to the longitudinal axis of the catheter body. The vascular access catheter can be provided in a vascular access kit, the kit further including an access needle including a hollow needle body and a beveled tip terminating in a sharp needle edge.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 030,410, entitled "OVER-THE-NEEDLE CATHETER," filed May 27, 2020, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to devices and methods for accessing a blood vessel, and more particularly, but not exclusively, to devices and methods for inserting a catheter into a blood vessel over an access needle. [Background technology]

[0003] Peripheral intravenous (PIV) catheterization is an invasive, in-hospital procedure for administering medications or other fluids, typically involving the insertion of a needle into a peripheral vein followed by the introduction of a catheter over the needle. Upon fluid administration, the needle is withdrawn, leaving at least the catheter tip and opening patent for fluid delivery. PIV catheterization procedures are traditionally associated with a substantial failure rate manifested by the catheter being removed from the vein before the end of the intended dwell time. Common causes of failure include "infiltration," where the catheter and / or needle penetrates the portion of the vein wall opposite the entry into the vein, and "occlusion," where the catheter and / or needle penetrates the portion of the vein wall opposite the entry into the vein, and optionally loss of infusion capacity due to infiltration and inflammation of the vein (phlebitis) due to thrombosis of the catheter or the vein itself. Summary of the Invention

[0004] The present disclosure relates to devices and methods for accessing a blood vessel, and more particularly, but not exclusively, to devices and methods for inserting a catheter into a blood vessel over an access needle.

[0005] In one embodiment, a vascular access catheter is provided that includes an elongated tubular catheter body that surrounds a lumen. The catheter body includes a catheter tip that terminates at the catheter distal end and includes a distal edge at the catheter distal end that surrounds an opening leading to the lumen. The distal edge includes a leading edge that spans a top of the opening and a beveled edge that spans a bottom of the opening and is angled proximally away from the leading edge relative to a longitudinal axis of the catheter body.

[0006] In some embodiments, the lumen is cylindrical along a portion of the catheter body proximate the catheter tip and tapers along a portion of the catheter tip.

[0007] In some embodiments, the leading edge substantially conforms to a transverse plane of the catheter body perpendicular to the longitudinal axis. In some embodiments, the leading edge spans at least half of the cross section of the catheter body at the distal end parallel to the transverse plane. In some embodiments, the beveled edge is beveled at an average angle of less than 45° relative to the transverse plane or leading edge.

[0008] In some embodiments, the leading edge is at least partially flat, hi some embodiments, the beveled edge is at least partially curved.

[0009] In some embodiments, the radius of curvature of the beveled edge is smallest adjacent the leading edge and / or largest adjacent the apex of the beveled edge, hi some embodiments, the radius of curvature of the beveled edge gradually increases between the leading edge and the apex of the beveled edge.

[0010] In some embodiments, the beveled edge includes or is integral with a sliding surface, where the sliding surface is at least partially parallel or inclined at a shallow angle to the beveled edge and / or the longitudinal axis. In some embodiments, the sliding surface forms a shaped region bounded by and between a distal parabola and a proximal parabola, the distal parabola having a shorter focal length than the proximal parabola. In some embodiments, the sliding surface is at least partially curved. In some embodiments, the catheter tip varies in thickness along the sliding surface. In some embodiments, the mean radius of curvature of the sliding surface is substantially greater than the radius of the outer surface of the catheter tip facing the sliding surface in a mutual cross section.

[0011] In some embodiments, the beveled edge includes two curved surfaces disposed on opposite sides of the opening relative to the longitudinal axis, with each of the sliding surfaces positively merging with the leading edge at a different merging portion.

[0012] In some embodiments, the catheter is configured to engage the inner vascular surface with the beveled edge when pressed over the access needle, and to slide distally over the inner vascular surface with the beveled edge when the catheter tip is pressed against the vessel wall and the access needle is withdrawn from the catheter tip.

[0013] In some embodiments, the leading edge merges with the beveled edge at a merger, and the merger is rounded, curved, and / or beveled.

[0014] In some embodiments, the integration portion is located adjacent to or below the longitudinal axis.

[0015] In some embodiments, the catheter tip includes a groove extending along the lower end of the catheter tip and leading closely from the beveled edge to the beveled edge, In some embodiments, the catheter tip includes a narrow cut or slit extending along the lower end of the catheter tip and leading closely from the beveled edge to the beveled edge.

[0016] In some embodiments, the beveled edge forms a first tangent angle adjacent its apex to the longitudinal axis that is less than about 20°, hi some embodiments, the beveled edge forms a second tangent angle adjacent the leading edge to the longitudinal axis that is greater than about 45°.

[0017] In some embodiments, the lower end of the catheter tip has a lower elastic resistance to radially inward deformation than the upper end of the catheter tip, hi some embodiments, the catheter tip is configured to collapse radially inward when the lower end of the catheter tip is pressed against the vessel wall at an angle when not internally supported by the access needle and the catheter body transmits insufficient force to the vessel wall to cause mechanical damage to the vessel wall.

[0018] In some embodiments, the catheter is configured such that the catheter tip, when collapsed radially inward along its lower end, has a footprint on the surface of the vessel wall that is larger than the maximum cross-section of the access needle.

[0019] In some embodiments, a vascular access kit is provided that includes a vascular access catheter and an access needle that includes a hollow needle body and a beveled tip that terminates in a distal sharp needle edge, In some embodiments, the catheter distally is configured to receive the access needle through the lumen and opening in at least two configurations, including a tissue penetrating configuration in which the beveled tip extends entirely from the lumen to the catheter distal end, and a safety configuration in which the beveled tip resides entirely within the lumen proximate the catheter distal end.

[0020] In some embodiments, the lumen reduces in diameter along the catheter tip to a sealing diameter smaller than the diameter of the access needle proximate the beveled tip to form a seal around the access needle to prevent blood from accessing the lumen through the opening when in the tissue penetrating configuration and to facilitate blood access to the lumen through the opening when in the safety configuration.

[0021] In some embodiments, the kit includes a coupling means configured to secure the access needle within the catheter in the tissue penetrating configuration.

[0022] In some embodiments, when in the tissue penetrating configuration, the needle edge is equal to or greater than the apex of the beveled edge than the apex of the leading edge.

[0023] In some embodiments, the kit is configured such that when the catheter tip collapses radially inward along its lower end, it has a footprint on the surface of the vessel wall that is larger in size than the maximum size of a lesion that can be formed in the vessel wall by the access needle.

[0024] In one embodiment, a method of inserting a catheter into a blood vessel using a kit is provided, comprising: The method includes inserting the catheter tip into the blood vessel when the catheter and access needle are in a tissue-penetrating configuration, transitioning the catheter and access needle to a safety configuration by moving the beveled tip relative to the catheter tip so that the beveled tip is entirely within the lumen proximate to the catheter distal end, engaging the inner surface of the blood vessel with the beveled edge, removing the access needle from the lumen, and advancing the catheter distally within the blood vessel.

[0025] In some embodiments, the inserting step includes creating a lesion on the inner surface of the vessel wall with the beveled tip, the engaging step includes sliding a remote portion of the inner surface from an opposite side of the lesion with the beveled edge, and the advancing step includes sliding the beveled edge and / or the catheter tip along its lower edge over and across the lesion.

[0026] In some embodiments, the inserting step includes and / or is followed by verifying whether blood is aspirated from the blood vessel into the access needle. In some embodiments, if the verifying is to discard blood aspirated into the access needle, the catheter is withdrawn after the transitioning step until verifying blood is aspirated from the blood vessel into the lumen. In some such embodiments, withdrawal occurs after the transitioning or detaching step and before the engaging step.

[0027] In some embodiments, the engaging step occurs after verification blood has been aspirated from the blood vessel into the lumen after the transferring step.

[0028] In some embodiments, the inserting step includes verifying that the catheter is secured to the access needle in a tissue penetrating configuration and penetrating the blood vessel with the beveled tip to allow blood to be aspirated from the blood vessel into the access needle, in some embodiments, the inserting step includes verifying that the bottom is oriented toward the blood vessel and / or the top is oriented away from the blood vessel.

[0029] In some embodiments, the inserting step includes and / or is followed by verifying that the blood vessel is diseased and / or is a vein having a diameter equal to or less than the catheter body or equal to or less than about 1 mm.

[0030] All technical or / and scientific words, terms, or / and phrases used herein have the same or similar meaning as commonly understood by those skilled in the art to which the present invention pertains, unless otherwise defined or described herein. The exemplary embodiments of the methods (steps, procedures), equipment (apparatus, system, its components), instruments, and materials illustratively described herein are exemplary and illustrative, and are not necessarily intended to be limiting. Although methods, equipment, instruments, and materials equivalent or similar to those described herein may be used in the practice or / and testing of the embodiments of the present invention, exemplary methods, equipment, instruments, and materials are illustratively described below. In case of conflict, the present patent specification, including definitions, shall control. [Brief description of the drawings]

[0031] Some embodiments are described herein, by way of example only, with reference to the drawings accompanying this specification. Reference will now be made in detail to certain drawings, where it is stressed that the details are shown by way of example and for purposes of illustrative description of some embodiments. In this regard, the description accompanying the accompanying drawings will make apparent to those skilled in the art how to practice some embodiments.

[0032] In the drawing [Figure 1A] 1 illustrates an exemplary over-the-needle catheter, according to some embodiments. [Figure 1B] 1 illustrates an exemplary over-the-needle catheter, according to some embodiments. [Figure 2A] 1 illustrates a schematic diagram of an exemplary scenario depicting steps in a method for inserting an exemplary catheter over a needle into a blood vessel, according to some embodiments. [Figure 2B] 1 illustrates a schematic diagram of an exemplary scenario depicting steps in a method for inserting an exemplary catheter over a needle into a blood vessel, according to some embodiments. [Figure 2C]1 illustrates a schematic diagram of an exemplary scenario depicting steps in a method for inserting an exemplary catheter over a needle into a blood vessel, according to some embodiments. [Figure 3A] FIG. 1 illustrates a schematic diagram of a first exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 3B] FIG. 1 illustrates a schematic diagram of a first exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 3C] FIG. 1 illustrates a schematic diagram of a first exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 3D] FIG. 1 illustrates a schematic diagram of a first exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 4A] FIG. 13A illustrates a schematic diagram of a second exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 4B] FIG. 13A illustrates a schematic diagram of a second exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 5A] FIG. 13A illustrates a schematic diagram of a third exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 5B] FIG. 13A illustrates a schematic diagram of a third exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 5C] FIG. 13A illustrates a schematic diagram of a third exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 5D] FIG. 13A illustrates a schematic diagram of a third exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 5E] FIG. 13A illustrates a schematic diagram of a third exemplary tip of an over-the-needle catheter, according to some embodiments. [Figure 6A] 1 illustrates a drawing of an exemplary vascular access kit, according to some embodiments. [Figure 6B]1 illustrates a drawing of an exemplary vascular access kit, according to some embodiments. [Figure 6C] 1 illustrates a drawing of an exemplary vascular access kit, according to some embodiments. [Figure 7A] 6B illustrates a drawing of an exemplary vascular access catheter of the kit shown in FIG. 6A according to some embodiments. [Figure 7B] 6B illustrates a drawing of an exemplary vascular access catheter of the kit shown in FIG. 6A according to some embodiments. [Figure 7C] 6B illustrates a drawing of an exemplary vascular access catheter of the kit shown in FIG. 6A according to some embodiments. [Figure 8A] 6B illustrates generally a first set of exemplary scenarios representing steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 8B] 6B illustrates generally a first set of exemplary scenarios representing steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 8C] 6B illustrates generally a first set of exemplary scenarios representing steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 8D] 6B illustrates generally a first set of exemplary scenarios representing steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 8E] 6B illustrates generally a first set of exemplary scenarios representing steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 9A] 6B illustrates a second set of exemplary scenarios depicting steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 9B]6B illustrates a second set of exemplary scenarios depicting steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 9C] 6B illustrates a second set of exemplary scenarios depicting steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 9D] 6B illustrates a second set of exemplary scenarios depicting steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 9E] 6B illustrates a second set of exemplary scenarios depicting steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. [Figure 9F] 6B illustrates a second set of exemplary scenarios depicting steps in a method of accessing a vessel using the kit shown in FIG. 6A, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Certain embodiments relate to devices and methods for accessing a blood vessel, and more particularly, but not exclusively, to devices and methods for inserting a catheter into a blood vessel over an access needle.

[0034] In some embodiments, the catheter has a catheter tip that terminates in a distal edge that has different structural and / or functional characteristics at the top of the catheter tip relative to the bottom of the catheter tip, such that the catheter tip is configured to interact differently with the interior wall of the blood vessel when engaging the vessel wall with the bottom part of the catheter tip than with the top part of the catheter tip under the same forces and conditions when the catheter tip is not internally supported by the needle. In some embodiments, the bottom part of the catheter tip is of a different structure and / or shape than the top part of the catheter tip proximate the distal edge. In some such or other embodiments, the distal edge is of a different shape proximate the bottom part of the catheter tip than the top part.

[0035] 1A-1B illustrate an exemplary over-the-needle catheter (100) configured, for example, as a peripheral intravenous catheter. The catheter (100) includes an elongated catheter body (101) terminating in a catheter tip (102) and connected at its proximal end to a catheter hand-handle (103). The hand-handle (103) includes wings (104) configured for manual handling and / or for securing the catheter to a patient's body, such as by using an adhesive. The hand-handle (103) also optionally includes a syringe connector (105) configured to connect to a syringe to facilitate injection of a fluid (e.g., a medication).

[0036] The catheter (100) may be provided in a peripheral venous access kit that also includes an access needle (107). As shown, the needle (107) is configured to extend through the lumen of the catheter body (101) with its needle tip (108) configured to fully protrude distally from the catheter tip (102) when the access needle (107) extends fully therethrough and is appropriately secured to the hand-handle (103) and oriented (rotationally) therewith using the needle securing member and / or the orientation member (109). A line connector (106) connected to the proximal end of the access needle (107) is configured to be connected to a syringe and / or an optional intravenous infusion line. The needle (107) can be partially or fully withdrawn (proximally) relative to the catheter tip (102) after disconnecting it from the hand-handle (103) and pulling the access needle (107) with the needle wings (110).

[0037] As shown in FIG. 1B, the catheter tip (102) has a distal edge (111) between the top (112) and bottom (113) of the catheter tip (102), the distal edge (111) being of a different shape and / or configuration adjacent the bottom (113) than adjacent the top (112).

[0038] In some embodiments, the catheter may be inserted into the blood vessel using one or more of the following steps (not necessarily in the same order):

[0039] > verifying that the catheter is properly positioned such that an exterior surface along a lower portion of the catheter tip is oriented toward the blood vessel and / or such that an exterior surface along an upper portion of the catheter tip is oriented away from the blood vessel;

[0040] > inserting the access needle into the blood vessel until blood enters the access needle and can be seen in an optional flashback chamber, which may be provided with the kit or integrated into the catheter or part thereof;

[0041] > pushing the access needle with the catheter or pushing the catheter over the access needle toward the inner (e.g., deeper) surface of the wall of the blood vessel while the catheter tip is internally supported by the access needle;

[0042] > moving the catheter body relative to the access needle so that the catheter tip is no longer internally supported by the access needle (typically so that blood is visible inside the catheter between the catheter tube and the needle);

[0043] > engaging the inner surface with the bottom and / or a portion of the distal edge proximate to the bottom of the catheter tip;

[0044] >Advancing the catheter distally into the blood vessel, thereby sliding it over the inner surface.

[0045] 2A-2C show schematic diagrams of exemplary scenarios depicting steps in a method for inserting a catheter (100) over an access needle (107) into a blood vessel (BV). FIG. 2A shows a first scenario after penetration of the catheter (100) into the blood vessel (BV). A sharp needle tip (108) is applied to penetrate the skin and the outer (e.g., shallower) wall (SW) of the blood vessel (BV), and the catheter tip (102) surrounds the needle (107) and is located proximal to the needle tip (108). FIG. 2B shows an optional second scenario in which the catheter tip (102) is advanced with or over the access needle (107) until it engages the inner (e.g., deeper) wall (IW) of the blood vessel (BV) generally opposite the outer wall (SW). FIG. 2C shows a third scenario in which the needle (107) is partially or fully withdrawn relative to the catheter tip (102) and the catheter tip is advanced further distally within the blood vessel (BV), optionally bending and / or sliding on the inner wall (IW).

[0046] A common failure involving needles and catheters in initial penetration into blood vessels, particularly small blood vessels, is the formation of an unintentional injury or lesion, such as a lesion (LS) (shown in FIG. 2C) on the inner wall (IW) of the blood vessel (BV) at the needle tip. In such a case, if a typical catheter tip is pushed forward (distally) over a needle similar to the access needle (107), there is a substantial possibility that it will further injure the blood vessel (BV) by enlarging or collapsing the lesion (LS), and / or penetrate out of the lumen of the blood vessel (BV) through the lesion (LS). Thus, in some embodiments, the catheter tip (102) is configured to engage the inner wall (IW) sufficiently far (e.g., distally) from the initial trajectory of the access needle (107) aligned with the needle's longitudinal axis (114) immediately after penetration into the blood vessel (BV), thereby reducing the possibility of contacting a possible lesion, such as a lesion (LS) on the inner wall (IW) that can be formed by the needle tip (108). In some such or other embodiments, the catheter tip (102) is configured to have a curved bottom of the distal edge (111) and / or a bottom configured to collapse inward so that the footprint on the inner wall (IW) is sufficiently larger than the dimensions of the lesion (LS) thereby reducing the possibility of penetrating the lesion. In some such or other embodiments, the catheter tip (102) is configured to bend forward (e.g., distally) relative to the needle shaft (114) when the catheter tip (102) is at least partially unsupported by the needle (107), e.g., when the needle tip (108) is partially or fully withdrawn (proximally) relative thereto, as shown, for example, in FIG. 2C.

[0047] 3A-3C are schematic illustrations of a first exemplary configuration of a catheter tip (102) in an elastically relaxed (unstressed) state, according to some embodiments. FIG. 3A is an isometric view of the catheter tip (102), FIG. 3B shows a front view thereof, and FIG. 3C shows a bottom view thereof. As previously described, the catheter tip (102) includes a bottom portion (113) opposite a top portion (112) around a distal edge (111). The distal edge (111) optionally includes at least one beveled edge, optionally configured as a curved and / or beveled beveled edge (115) that is inclined between a more distally projecting portion of the distal edge (111) and a less distally projecting portion of the distal edge that is closer to the bottom portion (113) than the more distally projecting portion. The distal edge (111) may be at least partially tapered to facilitate penetration of the skin and outer blood vessel wall (SW) when advanced by the access needle (107).

[0048] The base portion (113) is configured to engage the vessel wall prior to the top portion (112) when the catheter body (101) is tilted relative to the vessel wall. In some embodiments, the base portion (113) has a smaller elastic resistance to inward radial deformation than an equivalent resistance of the top portion (112) and / or other portions of the catheter tip (102) adjacent the base portion (113).

[0049] As a result of this design, the catheter tip (102) is configured to collapse (e.g., bend, compress, or flex) radially inward when not internally supported by the access needle (107), when the base (113) is pressed against the vessel wall at an angle, and when the catheter body (101) transmits a force to the vessel wall that is insufficient to cause mechanical damage thereto. When collapsed, the base (113) has a footprint (i.e., contact area during or immediately after collapse) on the surface of the vessel wall that is larger in size than the maximum size lesion that can be formed in the vessel wall by the access needle. Because the maximum size of a lesion formed on the vessel wall by a needle is generally on the order of or less than the size of the cross-section of the needle tip (108), the catheter tip (102) can be designed and configured with a minimum footprint (under the same reasonable forces and conditions) that is larger in size than the maximum size cross-section of the access needle (107).

[0050] The catheter tip (102) is configured to maintain a substantially circular (or other generally rounded) cross-section when the top (112) is pressed at an angle against the lesion while the bottom (113) is configured to collapse when pressed against the lesion, transmitting the same force to the vessel wall. In either case, the catheter tip is configured such that the bottom (113), which has collapsed radially inward, elastically regains its nominally circular (or other generally rounded) cross-section when released from an external force applied thereto and returns to an elastically relaxed (unstressed) state. Unlike the described differences in elastic resistance to radial compression, the bottom (113) optionally has an elastic resistance to axial compression similar to that of the top (112).

[0051] Possible ways to obtain the structural and / or functional configuration that causes this difference in elastic resistance to radial compression between the top (112) and bottom (113) locations of the catheter tip (102) may include various mechanical, thermal and / or chemical treatments on each one of these portions, such as applying coatings of various types or thicknesses, using various materials, or otherwise as known in the relevant practice. For example, the bottom portion (113) may be formed separately from the top portion (112) (or the entire remainder of the catheter body (101)), optionally of a different material or under a different process or process than the top portion (112), and later connected to the remainder of the catheter body (101), for example, using an adhesive or thermal bonding.

[0052] As shown, the bottom portion (113) includes at least one slit (116) extending from and opening into the distal edge (111). The slit reduces the elastic resistance to radial compression locally, with the reduction being greater closer to the slit. The slit (116) forms opposing vertical edges (117) configured to twist inwardly toward the longitudinal axis (114) when the bottom portion (113) is pushed radially inward, as shown, for example, in FIG. 3D. The slit (116) is substantially straight and parallel to the longitudinal axis (114) so ​​as to maintain a similar (e.g., the same) resistance to axial compression adjacent the slit (116) as the top portion (112). Optionally, instead of or in combination with slits, the bottom portion (113) has at least one line of weakness extending therealong to reduce local structural resistance to radial compression relative to the top portion (112). The line of weakness is optionally configured to have a reduced thickness and / or reduced structural strength relative to adjacent portions of the bottom portion (113).

[0053] 4A-4B generally illustrate views of another exemplary configuration of a catheter tip (102) according to some embodiments. FIG. 4A shows a side cross-sectional view of the catheter tip (102), and FIG. 4B shows a bottom view thereof. As shown, the catheter body (101) encloses a lumen (118) and the catheter tip (102) terminates at a distal edge (111) forming an opening (119) to the lumen (118) between its upper (112) and lower (113) portions. In this exemplary configuration, the distal edge (111) includes a leading edge (120) extending substantially perpendicular to the longitudinal axis (114) from the top (112) to the bottom (113), and at least one beveled edge extending at an angle relative to the longitudinal axis (114) from the bottom (113) to the leading edge (120), optionally configured as a beveled edge (121) that merges with or is adjacent to the leading edge (120) at a merger portion (122) that is optionally located below the longitudinal axis (114) (coincident with the centerline of the catheter body (101)).

[0054] In this manner, the catheter (100) is configured to engage the inner vessel surface with the beveled edge (121) (as shown in FIG. 2) when pushed over the access needle (107), and the beveled edge (121) is configured to slide distally over the inner vessel surface when the catheter tip (102) is pressed against the vessel wall with the access needle (107) withdrawn therefrom. Optionally, the catheter (100) is further configured to engage the inner vessel surface with the beveled edge (121) proximal to the access needle (107).

[0055] The beveled edge (120) is curved and forms an angle with the longitudinal axis (114) adjacent the base (113) that is substantially less (optionally about 20° or less) than the angle adjacent the leading edge (120) (optionally about 45° or more).

[0056] The base (113) includes a groove (123) extending proximally from and opening onto the beveled edge (121), which is optionally in the form of a narrow cut, but may additionally or alternatively include at least one slit. In some embodiments, the catheter tip (102) is tapered, decreasing in outer diameter and / or thickness towards the distal end (111) to facilitate penetration of the catheter into the skin and into the blood vessel.

[0057] Reference is made to Figures 5A-5E, which diagrammatically illustrate views of a third exemplary configuration of a tip (102), according to some embodiments. Figures 5A and 5B show a side cross-sectional view and a bottom view, respectively, of the catheter tip (102). Figure 5C shows an axial projection view of the forward (distal) portion of the catheter tip (102). Figure 5D shows a side view of the catheter tip (102) properly positioned over an access needle (107) for penetration into a blood vessel (e.g., a vein). Figure 5E is an enlarged view of segment "S5E" of Figure 5D. As with the previous examples, the catheter (100) includes an elongated tubular catheter body (101) surrounding a lumen (118) extending its entire length along a longitudinal axis (114), the catheter being configured to pass over an access needle (e.g., needle (107)) to a blood vessel. The catheter body (101) includes a catheter tip (102) that terminates in a distal edge (111) that forms an opening (119) to a lumen (118) between an upper portion (112) and a lower portion (113).

[0058] In this exemplary configuration, the distal edge (111) includes a leading edge (120) extending from the top (112) toward the bottom (113), the leading edge being in a direction substantially perpendicular to the longitudinal axis (114). The distal edge (111) further includes at least one beveled edge (130) having a contour or boundary substantially parallel to the longitudinal axis (114) at least a portion of it (e.g., as shown, along a majority of it, or substantially its entire length). The leading edge (120) merges with the beveled edge (130) at a curved merger located below the longitudinal axis (114), optionally proximate the relative height level of the bottom (113). In some embodiments, the catheter tip (102) is tapered, decreasing in outer diameter and / or thickness toward the distal end (111), to facilitate penetration of the catheter into the skin and into the blood vessel.

[0059] The catheter (100) is configured to engage the inner vessel surface with the beveled edge (130) (e.g., as shown in FIG. 2) when pushed over the access needle (107) and to slide distally over the inner vessel surface with the beveled edge (130) when the catheter tip (102) is pressed against the vessel wall with the access needle withdrawn therefrom. Optionally, the catheter (100) is configured to first engage the inner vessel surface with the beveled edge (130) proximal to the access needle (107).

[0060] The beveled edge (130) includes two sliding surfaces (131) and (132) provided on different sides of the longitudinal axis (114). The sliding surfaces (131) and (132) are substantially flat along at least a majority of their surface area, and both extend along a common plane parallel to the longitudinal axis (114), parallel to a plan view of the catheter (100) (e.g., a top or bottom view as shown in FIG. 5B), and perpendicular to a front view (e.g., a side view as shown in FIG. 5A). In a typical peripheral venous access practice, after penetrating into a blood vessel, the catheter is typically advanced distally at a shallow angle approximately parallel to the vessel inner surface. Thus, the potential advantage of this design feature of the beveled edge (130) is two-fold. (a) unlike catheters with beveled and / or conical tips, which inherently encourage advancement of the catheter at a greater angle toward the inner vascular surface, the beveled edge (130) is substantially parallel to the catheter longitudinal axis (114), and therefore inherently encourages an axial sliding motion over the inner vascular surface, and / or (b) unlike known catheters, which are generally comprised of rounded edges and / or small footprints, the beveled edge (130) has a substantially larger footprint with sliding surfaces (131) and (132) that are also flat and smooth, thereby allowing for less traction and increased gliding over the inner vascular surface.

[0061] Each of the sliding surfaces (131) and (132) merges distinctly with the leading edge (120), with the first sliding surface (131) merging at a first merged portion (133) and the second sliding surface (132) merging at a second merged portion (134). The merged portions (133) and (134) are located on different sides of the longitudinal axis (114) and are laterally spaced therefrom, thereby reducing the likelihood of dissecting vessel wall tissue after the needle tip (108) unintentionally punctures the vessel wall at its inner surface, unlike other catheters which may engage a puncture formed by a single edge located adjacent the needle tip (108) and on the longitudinal axis (114) to further enlarge the puncture and ultimately sever tissue. Each one of the merging portions (133) and (134) is curved and / or angled to allow a smooth transition of the catheter (100) from a larger angle to a shallower angle relative to the vessel axis when the merging portions (134) and / or (135) directly engage the inner vessel surface. The beveled edge (130) further includes a single beveled edge (121) at the merging portion of both the sliding surfaces (131) and (132) with the bottom portion (113). The beveled edge (121) extends from the bottom portion (113) angled relative to the longitudinal axis (114) toward the leading edge (120).

[0062] Figures 6A-6C illustrate views of an exemplary vascular access kit (200) including at least a vascular access catheter (201) and an access needle (202). Figure 6A shows the catheter (201) and access needle (202) separated, and Figure 6B shows the access needle (202) extending through the catheter (201) and fixedly connected thereto at a predetermined relative longitudinal position. Figure 6C is a close-up (zoomed-in) view of the distal portion of the kit (200) of Figure 6B, showing the beveled tip (203) of the access needle (202) and the catheter tip (204) of the catheter (201). 7A-7C show views of catheter (201) including a partial isometric view of the distal length of catheter (201) showing a portion of the catheter body with catheter tip (204) (FIG. 7A), a close-up view showing the front of catheter tip (204) (FIG. 7B), and a side cross-sectional view of the distal length of catheter (201) including catheter tip (204) (FIG. 7C).

[0063] The catheter (201) includes an elongated tubular catheter body (205) that surrounds a lumen (206). The lumen (206) is cylindrical along a portion (e.g., most) of the catheter body (205) proximate the catheter tip (204) and tapers along a portion of the catheter tip (204). The front (distal) portion of the catheter body (205), the catheter tip (204), terminates at the catheter distal end (207) that includes a distal end (208) that surrounds an opening (209) into the lumen (206). The access needle (202) includes a hollow needle body (210) and a beveled needle tip (203) that terminates in a distal sharp needle edge (211). The catheter (201) is configured to receive the access needle (202) through the lumen (206) and opening (209) in at least two configurations, including a "tissue penetrating configuration" (e.g., shown in Figures 6B, 8A, and 9A) in which the beveled tip (203) extends completely distally from the lumen (206) to the catheter distal end (207), and a "safety configuration" (e.g., shown in Figures 8B and 9B) in which the beveled tip (203) resides completely within the lumen (206) adjacent to the catheter distal end (207). The lumen (206) reduces in diameter proximate the beveled tip (203) along the catheter tip (204) to a sealing diameter smaller than the diameter of the access needle, thereby forming a seal around the access needle (202) to prevent blood from accessing the lumen (206) through the opening (209) when in the tissue penetrating configuration and to facilitate blood access to the lumen (206) through the opening (209) when in the safety configuration. The catheter (201) and access needle (202) include a mating portion of a coupling means (212), optionally in the form of a luer fitting as shown, configured to secure the access needle (202) to the catheter (201) in the tissue penetrating configuration.

[0064] The distal edge (208) includes a leading edge (213) that straddles the top of the opening (209) and a beveled edge (214) that straddles the bottom of the opening (209) and slopes proximally away from the leading edge (213) (toward the bottom end of the catheter tip (204)) relative to the longitudinal axis (X) of the catheter body (201). The top of the opening (209) refers to the cross-sectional area of ​​the opening (209) above the longitudinal axis (X) and the bottom of the opening (209) refers to the cross-sectional area of ​​the opening (209) below the longitudinal axis (X) (as shown in FIG. 7C). The leading edge (213) substantially coincides with a transverse cross-section (TP) of the catheter body (205) perpendicular to the longitudinal axis (X). Optionally, the leading edge (213) spans at least half of the cross-section of the catheter body (205) at the distal end (207). Optionally, the leading edge (213) is substantially parallel to the cross-section (TP) at least over a majority of the length. The beveled edge (214) is beveled at an average angle of more than 20°, optionally more than 40°, and optionally more than 60°, relative to the longitudinal axis (X) and / or at an average angle of less than 45°, optionally less than 30°, and optionally less than 20°, relative to the leading edge (213) or the cross-section (TP).

[0065] In some embodiments, the leading edge (213) is at least partially flat and the beveled edge (214) is at least partially curved. Optionally, the radius of curvature of the beveled edge (214) is smallest adjacent the leading edge (213) and / or largest adjacent the apex (215) of the beveled edge (214), optionally gradually increasing between the leading edge (213) and the apex (215), optionally especially increasing between the leading edge (213) and the apex (215). In some embodiments, the beveled edge (214) forms a tangent angle with the longitudinal axis (X) adjacent its apex (215) that is less than about 20°, and / or forms another tangent angle with the longitudinal axis (X) adjacent its merger with the leading edge (213) that is greater than about 45°.

[0066] In some embodiments, the catheter (201) is configured to engage the inner vessel surface with a beveled edge (214) when pushed over the access needle (202) and to slide distally on the inner vessel surface with the beveled edge (214) when the catheter tip (204) is pushed against the vessel wall when the access needle (202) is withdrawn from the catheter tip (204). Prior art catheters that include a flat leading end without a significant bevel and / or curved portion tend to scratch the vessel wall with their lower end acting as a sharp edge when the catheter engages the vessel wall and is pressed against the vessel wall at an angle relative to the vessel long axis. The use of a curved beveled edge (214) can overcome this drawback by first reducing or eliminating sharpness and / or by having a larger footprint area to engage the vessel wall, thereby reducing the likelihood of scratching or penetrating the vessel wall. Additionally, because the tangent of the curved beveled edge (214) at some or all of the contact points with the vessel wall is parallel or nearly parallel to the vessel longitudinal direction, a larger tangential force component can be distributed in the longitudinal direction of the vessel lumen and a smaller normal force component in the direction perpendicular to the vessel wall from the force applied to push the catheter, as compared to prior art catheters. Note that the distal edge (208) is not fully beveled and / or curved, and thus includes an oversized leading edge (213) to maintain sufficient structural integrity of the catheter tip (204) while penetrating skin tissue over the access needle (202) and / or while penetrating a blood vessel in a tissue penetrating configuration.

[0067] The beveled edge (214) includes or is integral with a sliding surface (217). The sliding surface (217) is optionally at least partially curved and / or flat and at least partially parallel or inclined at a shallow angle (e.g., less than 45°, and optionally particularly less than 20°) to the beveled edge (214) and / or the longitudinal axis (X). The sliding surface (217) forms a shaped region bounded by the distal parabola (218) and the proximal parabola (219) such that the distal parabola (218) has a smaller focal length than the proximal parabola (219). In some embodiments, when the kit (200) is assembled in the tissue penetrating configuration, the needle edge (211) has an equidistant or greater distance to the apex (215) of the beveled edge (214) (which is the apex of the distal parabola (218)) than the apex (216) of the leading edge (213) shown in FIG. 6C. In some embodiments, the catheter tip (204) varies in thickness along the sliding surface (217), which has a mean radius of curvature that is substantially greater than the radius of the portion of the outer surface of the catheter tip that faces the sliding surface (217) in a mutual cross-sectional plane. In some embodiments, the sliding surface (217) has a smaller elastic resistance to radially inward deformation than the opposing portion (along the top end) of the catheter tip (204). In some embodiments, the kit (200) is configured such that when collapsed radially inward, the catheter tip (204) along its base or end has a footprint on the surface of the vessel wall that is larger in size than the maximum size lesion that can be formed in the vessel wall by the access needle (202).

[0068] In addition to preventing damage to the vessel wall by engaging the inner vessel surface with the curved beveled edge (214), the catheter tip (204) is optionally configured to reduce the likelihood of unintentionally penetrating the vessel wall with the sharp needle edge (211) and increasing the size and / or severity of an existing lesion when the kit (200) is secured in the tissue penetrating configuration, e.g., by enlarging the puncture size and / or advancing the catheter (201) through the puncture and out of the vessel lumen. The beveled edge (214) includes two curved surfaces (220) provided on opposing sides of the opening (209) across the longitudinal axis (X), each one of the sliding surfaces (220) merging with the leading edge (213) differently at different merging sections (221). In this manner, when the catheter tip (204) engages the preformed lesion, initial contact and sliding across the lesion occurs directly at the sliding surface (220) spaced apart from the lesion width (equal to or less than the diameter of the access needle (202)). Each integral portion (221) is optionally rounded, curved, and / or angled, and is optionally positioned adjacent to or below the longitudinal axis (X).

[0069] 8A-8E illustrate a first set of exemplary scenarios representing steps in a method of accessing (inserting) a blood vessel (BV) using a kit (200). As shown in FIG. 8A, the catheter (201) and access needle (202) of the kit (200) are first assembled and secured together in a tissue-penetrating configuration, and then pushed through a skin layer of a living subject until the beveled tip (203) penetrates the blood vessel (BV) to allow blood to be aspirated from the blood vessel (BV) into the access needle (202). The size of the kit (200) is determined according to the blood vessel dimensions such that by correctly positioning the beveled tip (203) in the lumen of the blood vessel (BV) in the tissue-penetrating configuration, the catheter tip (204) is also inserted (e.g., mostly or completely) into the blood vessel (BV). The process of inserting the catheter may include verifying that the bottom of the opening (209) or catheter tip (204) is oriented into the blood vessel (BV) and / or that the top of the opening (209) or catheter tip (204) is oriented away from the blood vessel (BV) to indicate correct location and orientation. For example, as shown, when properly penetrating through the skin and into the blood vessel (BV), the top of the leading edge (213) acts as the leading edge of the catheter, while the beveled edge (214) is far enough proximally away to reduce or not significantly increase the contribution of the leading edge portion (213) to physical interaction with the surrounding tissue during catheter insertion.

[0070] Once the bevel tip (203) enters the lumen of the blood vessel (BV), the medical practitioner may verify that blood is aspirated from the blood vessel (BV) into the access needle (202), which may indicate proper positioning of the bevel needle (203). The catheter (201) and access needle (202) may then be transitioned to a safe configuration (as shown in FIG. 8B), such as by moving the bevel tip (203) relative to the catheter tip (204) such that the bevel tip (203) is fully contained within the lumen (206) proximate the catheter distal end (207). This transitioning step may occur after or include changing the inclination of the catheter (201) with the access needle (202) relative to the blood vessel (BV) and / or repositioning the catheter (201) and / or the access needle (202) in the blood vessel (BV).

[0071] When in the safety configuration, the medical practitioner can verify that blood is aspirated from the blood vessel (BV) into the lumen (206) of the catheter (201) before proceeding to complete its deployment. The access needle (202) can then be withdrawn further and / or the catheter (201) can be pushed forward (distally) beyond the needle (202), which may include engaging the inner (e.g., deeper) surface of the blood vessel (BV) with the beveled edge (214), as shown in FIG. 8C. The access needle (202) can be removed entirely from the lumen (206) and optionally replaced with a fluid source, such as a syringe connectable to the catheter (201) with the coupling means (212), which can be used to flush the catheter and / or administer medication to the blood vessel (BV) via the catheter (201). Removal of the access needle (202) and / or coupling to a syringe may be performed while compressing the blood vessel (BV) distally to the catheter tip (204), as shown in Figure 8D. The catheter (201) can then be advanced distally within the vessel (Figure 8E) for final positioning and deployment.

[0072] 9A-9F diagrammatically illustrate a second set of exemplary scenarios representing steps in a method for accessing a blood vessel (BV) using the kit (200). In this set of scenarios, a medical practitioner may intentionally (e.g., intentionally) or unintentionally push an access needle (202) with a catheter (201) in a tissue-penetrating configuration across the entire width of a blood vessel (BV) such that the beveled tip (203) penetrates both an upper (shallow) portion of the blood vessel (BV) and an opposing lower (deep) portion of the blood vessel (BV), as shown in FIG. 9A. In this example, inserting the catheter tip (204) into the blood vessel (BV) when in the tissue-penetrating configuration includes, but results in, forming a lesion (LS) through the inner surface of the blood vessel (BV) wall with the beveled tip (203) (e.g., as shown in FIG. 9C). The catheter (201) may then be withdrawn back into the lumen of the blood vessel (BV) until the correct positioning is reached and / or verified before proceeding to the final deployment stage of the catheter (201) in the blood vessel (BV). Prior to withdrawing the catheter (201), the access needle (202) may be partially withdrawn (e.g., to a safety configuration) or fully withdrawn (e.g., removed) from the catheter (201).

[0073] After a "double penetration" of the blood vessel (BV) as shown in FIG. 9A, the medical practitioner may first verify whether blood has been aspirated from the blood vessel (BV) into the access needle (202), however, in this scenario, the verification may result in invalidating that blood has been aspirated into the access needle (i.e., indicating or proving that blood was not actually aspirated from the blood vessel (BV) into the access needle (202). As a result of such, the catheter (201) and access needle (202) may first be transitioned to a safety configuration (FIG. 9B), or alternatively, the access needle (202) may be removed from the catheter (201), after which the catheter (201) may be gradually withdrawn, optionally with the access needle (202) maintained in a safety configuration (FIG. 9C), until confirmation is made that blood has been aspirated from the blood vessel (BV) into the lumen (206) (indicating or proving that the catheter tip (204) has been inserted into the blood vessel (BV)). The catheter (201) can then be pushed in by sliding the sliding surface (220) of the beveled edge (214) over a remote portion of the inner surface of the blood vessel (BV) from the opposite side of the lesion (LS) to engage the inner surface of the blood vessel (BV) with the beveled edge (214) (FIG. 9D) in order to pass the lesion (LS) without re-penetrating the lesion or damaging the surrounding tissue. If not already done in a previous step, the access needle (202) can be completely removed from the lumen (206) of the catheter (201) (FIG. 9E) and the catheter (201) can be advanced distally to a selected deployment location (FIG. 9F). Advancement of the catheter (201) can optionally include sliding over and through the lesion (LS) along the beveled edge (214) and / or the lower end including the sliding surface (217) at the catheter tip (204).

[0074] In some embodiments, the advantage of using the catheter (201) and / or kit (200) may be particularly suitable for accessing diseased or very small veins. In small veins, the diameter at the access point may be approximately the same as or smaller than the catheter body, and therefore there is a possibility of at least some engagement of the vessel wall by the distal end or part of the prior art catheter tip at any point during the access and deployment process. Thus, by applying a catheter (201) having a beveled edge (214), a smaller relative height can be achieved during angled penetration into the vessel than a standard catheter. In some such embodiments, a preliminary step in the method of using the kit (200) to deploy the catheter (201) may include identifying that the vessel is diseased and / or a vein of the same or smaller diameter than the catheter body or a vein smaller than about 1 mm.

[0075] As used herein, each of the following terms "a," "an," and "the," written in singular grammatical form, means "at least one," or "one or more." The use of the phrase "one or more" herein does not change this intended meaning of "a," "an," or "the." Thus, as used herein, the terms "a," "an," and "the" may refer to and include a plurality of the described entities or objects, unless otherwise defined or described herein or unless otherwise clearly indicated by the context. For example, as used herein, the phrases "unit," "device," "assembly," "mechanism," "component," "element," and "step or procedure" may refer to and include a plurality of units, a plurality of devices, a plurality of assemblies, a plurality of mechanisms, a plurality of components, a plurality of elements, and a plurality of steps or procedures, respectively.

[0076] As used herein, each of the following terms "includes," "including," "has," "having," "comprises," and "comprising," and their linguistic / grammatical variations, derivatives, and / or conjugates, mean "including, but not limited to," and should be considered as embodying the recited components, features, properties, parameters, integers, or steps, and not excluding the addition of one or more additional components, features, properties, parameters, integers, steps, or groups thereof. Each of these terms is considered to have the same meaning as the expression "consisting essentially of."

[0077] The term "method" as used herein refers to steps, procedures, methods, means, or / and techniques for accomplishing a given task, including, but not limited to, those readily developed by a practitioner in the art relevant to the disclosed invention from known steps, procedures, methods, means, or / and techniques.

[0078] Throughout this disclosure, numerical values ​​of parameters, features, characteristics, objects, or dimensions may be claimed or described in terms of a numerical range format. Such numerical range formats used herein are intended to illustrate the implementation of some exemplary embodiments of the present invention, and are not intended to rigidly limit the scope of the exemplary embodiments of the present invention. Thus, any claimed or described numerical range refers to and encompasses all possible subranges and individual numerical values ​​(wherein the numerical values ​​may be expressed as non-negative integers, integers, or decimals) within the claimed or described numerical range. For example, a claimed or described numerical range of "1-6" refers to and encompasses all possible subranges, such as "1-3", "1-4", "1-5", "2-4", "2-6", "3-6", and individual numerical values, such as "1", "1.3", "2", "2.8", "3", "3.5", "4", "4.6", "5", "5.2", and "6", within the claimed or described numerical range of "1 to 6". This applies regardless of the breadth, scope, or magnitude of the described numerical range.

[0079] Furthermore, when claiming or describing a numerical range, the phrase "within a range between about a first numerical value and about a second numerical value" is considered to have the same meaning as the phrase "within a range from about a first numerical value to about a second numerical value," and thus the two equivalent phrases may be used interchangeably. For example, when claiming or describing a numerical range of room temperature, the phrase "room temperature refers to a temperature range between about 20° C. and about 25° C." is considered to be equivalent and have the same meaning as the phrase "room temperature refers to a temperature range between about 20° C. and about 25° C.."

[0080] As used herein, the term "about" means ±10% of the stated numerical value.

[0081] It will be appreciated that certain aspects, properties, and characteristics of the invention that are, for clarity, illustratively described and presented in the context or form of multiple separate embodiments, may also be illustratively described and presented in any suitable combination or subcombination in the context or form of a single embodiment. Conversely, various aspects, properties, and characteristics of the invention that are illustratively described and presented in combination or subcombination in the context or form of a single embodiment may also be illustratively described and presented in the context or form of multiple separate embodiments.

[0082] While the present invention has been illustratively described and presented by way of certain exemplary embodiments and examples thereof, many alternatives, modifications, and / or variations thereof will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications, and / or variations within the spirit and broad scope of the appended claims.

[0083] All publications, patents, and / or patent applications cited or referenced in this disclosure are incorporated herein by reference in their entirety to the same extent as if each individual publication, patent, and / or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of a reference herein should not be construed or understood as an admission that the reference represents or corresponds to prior art to the present invention. In addition, the headings of each section should not be construed as necessarily limiting.

Claims

1. 1. A vascular access catheter comprising: an elongated tubular catheter body surrounding a lumen, the catheter body including a catheter tip terminating at a catheter distal end and including a distal edge at the catheter distal end surrounding an opening leading to the lumen, the vascular access catheter is configured to receive an access needle through the lumen and the opening; wherein the distal edge includes a leading edge that straddles the top of the opening, and a beveled edge that straddles the bottom of the opening and is angled proximally away from the leading edge relative to a longitudinal axis of the catheter body; wherein the beveled edge of the opening is at least partially curved in longitudinal cross-section, and the beveled edge includes or is integral with a sliding surface extending proximally along a bottom of the tubular catheter body, the sliding surface comprising one or more of grooves, slits, weakened portions, flat portions, and coatings such that the vascular access catheter easily slides along an inner wall of the blood vessel without damaging the inner wall of the blood vessel when the vascular access catheter is inserted into the blood vessel via the access needle.

2. 2. The vascular access catheter of claim 1, wherein the lumen is cylindrical along a portion of the catheter body proximate the catheter tip and tapers along a portion of the catheter tip to seal around the access needle as it extends therethrough.

3. The vascular access catheter of claim 1 , wherein the leading edge coincides with a cross-section of the catheter body perpendicular to the longitudinal axis.

4. The vascular access catheter of claim 3 , wherein the leading edge spans at least half of a cross-section of the catheter body at the distal end parallel to the transverse plane.

5. The vascular access catheter of claim 3 , wherein the beveled edge is beveled at an average angle of less than 45° relative to the cross section or the leading edge.

6. The vascular access catheter of claim 1 , wherein the leading edge is at least partially flat.

7. The vascular access catheter of claim 1 , wherein the radius of curvature of the beveled edge is smallest adjacent the leading edge and / or is largest adjacent the apex of the beveled edge.

8. The vascular access catheter of claim 1 , wherein the radius of curvature of the beveled edge gradually increases between the leading edge and an apex of the beveled edge.

9. A vascular access catheter as described in claim 1, wherein the sliding surface is at least partially parallel to the beveled edge and / or the longitudinal axis or is inclined at a shallow angle.

10. 10. The vascular access catheter of claim 9, wherein the sliding surface defines a shaped region bounded by and between a distal parabola and a proximal parabola, the distal parabola having a shorter focal length than the proximal parabola.

11. The vascular access catheter of claim 9 , wherein the sliding surface is at least partially curved.

12. The vascular access catheter of claim 9 , wherein the catheter tip has a varying thickness along the sliding surface.

13. 10. The vascular access catheter of claim 9, wherein the mean radius of curvature of the sliding surface is greater than the radius of an outer surface of the catheter tip opposite the sliding surface in mutual transverse cross section.

14. The vascular access catheter of claim 1 , wherein the beveled edge includes two curved surfaces on opposite sides of the longitudinal axis at the opening.

15. 2. The vascular access catheter of claim 1, wherein the catheter is configured to engage an inner vessel surface with the beveled edge and slide distally over the inner vessel surface when the access needle is forced upward as the catheter tip is pressed against a vessel wall and the access needle retracts from the catheter tip.

16. A vascular access catheter as described in claim 1, wherein the sliding surface extends along the lower end of the catheter tip and includes a groove portion adjacent to the beveled edge portion and leading to the beveled edge portion.

17. A vascular access catheter as described in claim 1, wherein the sliding surface extends along the lower end of the catheter tip and includes a narrow cut or slit extending closely adjacent to the beveled edge portion and leading to the beveled edge portion.

18. The vascular access catheter of claim 1 , wherein the beveled edge adjacent its apex forms a first tangent angle with respect to the longitudinal axis that is less than about 20°.

19. The vascular access catheter of claim 1 , wherein the beveled edge forms a second tangent angle adjacent the leading edge that is greater than about 45° with respect to the longitudinal axis.

20. A vascular access catheter as described in claim 1, wherein the sliding surface has an elastic resistance to radially inward deformation that is less than the upper end of the catheter tip.

21. 2. The vascular access catheter of claim 1, wherein the catheter tip is configured to deform so as to collapse radially inward when the lower end of the catheter tip is pressed against a blood vessel wall at a certain angle when the catheter body transmits a force to the blood vessel wall that is insufficient to cause mechanical damage to the blood vessel wall when the catheter tip is not internally supported by the access needle.

22. 2. The vascular access catheter of claim 1, wherein the catheter tip is configured along its lower end to have a contact area with the surface of the blood vessel wall during or immediately after deformation that is larger than the maximum cross-sectional size of the access needle when deformed to collapse radially inward.

23. 1. A vascular access kit comprising:

13. The vascular access catheter of claim 1; A vascular access kit comprising: an access needle including a hollow needle body and a beveled tip terminating in a distal sharp needle edge.

24. 24. The vascular access kit of claim 23, wherein the vascular access catheter is configured to accommodate an access needle through a lumen and an opening in at least two configurations, the two configurations including a tissue penetrating configuration in which the beveled tip extends entirely from the lumen to the catheter distal end, and a safety configuration in which the beveled tip resides entirely within the lumen proximate to the catheter distal end.

25. 25. The vascular access kit of claim 24, wherein the lumen reduces in diameter along the catheter tip to a sealing diameter smaller than a diameter of the access needle adjacent the beveled tip to form a seal around the access needle to prevent blood from accessing the lumen through the opening when in the tissue penetrating configuration and to facilitate blood access to the lumen through the opening when in the safety configuration.

26. The vascular access kit of claim 24 including a coupling means configured to secure the access needle within the catheter in the tissue penetrating configuration.

27. The vascular access kit of claim 24 , wherein when in the tissue penetrating configuration, the needle edge is a distance to an apex of the beveled edge that is equal to or greater than a distance to an apex of the leading edge.

28. The vascular access kit of claim 23, wherein the catheter tip is configured to, when deformed along its lower end by collapsing radially inward, have a contact area with the surface of the vessel wall during or immediately after deformation that is larger than the maximum size of a lesion that can be formed in the vessel wall by the access needle.

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