Patent ID: 12256951

DETAILED DESCRIPTION

FIGS.1A to1Dillustrate one embodiment of a catheter system12. InFIGS.1A and1B, system12is shown as a schematic view with components of the system in different positions. Catheter system12comprises a catheter20, a catheter34configured to extend at least partially through catheter20, and a needle wire32configured to extend through catheter34. Catheter20comprises a shaft18having a proximal end18aand a distal end18b. Shaft18at proximal end18ais coupled to a handle28through an optional resilient member14that defines a lumen in communication with the lumen of catheter20. Distal tip22is disposed at the distal end18b of shaft18.

FIGS.1C and1Dshow a magnified top, perspective view and bottom, perspective view of a distal tip22of catheter20. Distal tip22defines a lumen23that is in fluid communication with the lumen of shaft18. Distal tip22comprises a side aperture21disposed between a proximal end22aand a distal end22bof the distal tip. Distal tip22also comprises an aperture29at distal end22b. Both side aperture21and aperture29are in fluid communication with lumen23of distal tip22. Distal tip22and needle wire32are configured such that the distal end of needle wire can extend through lumen23and distal end aperture29(e.g., a transverse dimension of the aperture and conduit is greater than a maximum transverse dimension of the needle wire). Side aperture21and catheter34are configured such that catheter34can extend through the side aperture (e.g., cross-sectional dimension of the aperture is greater than a maximum transverse, cross-sectional dimension of catheter34) when entering lumen23through proximal end22a. In the embodiment shown, the transverse cross-sectional area of lumen23is greater at the proximal end22athan the distal end22bsince the distal end22bonly needs to accommodate needle wire32.

Distal tip22can also comprise side aperture41(FIG.1C) and/or side aperture42(FIG.1D). Side apertures41and/or42can be disposed between proximal end22aand distal end22bof distal tip22and can be in fluid communication with lumen23of distal tip22. Distal tip22can comprise a radiopaque material that defines at least a portion of side aperture41and/or side aperture42. Side aperture41and/or side aperture42can be used as reference guide during the circumferential alignment of catheter20. The visibility of side aperture41and/or42will vary with the axial rotation distal tip22. When viewing a real-time radiographic image of distal tip22, side apertures41and/or42will appear widest and/or brightest when the plane of a radiographic detector is aligned with (e.g., in the same plane as) apertures41and/or42. The aiming and alignment of the distal tip22will be described in further detail below. This angle can be used to select the projection angle at which catheter34extends from side aperture21and/or define the exit path of a needle wire32advancing from catheter34. When the projection angle of catheter34substantially corresponds to the angle of the detector plane, the exit path of needle wire32will intersect the desired exit site on the patient. In some embodiments, side aperture21can also be defined by a radiopaque material to facilitate the rotational alignment and angle setting process. Distal tip22can be coupled to or integral with shaft18.

Catheter34is configured to extend through side aperture21at an angle relative to the longitudinal axis Y of catheter20. The angle is defined by the section of catheter34extending through side aperture21and is referred to as the projection angle θ (seeFIG.31). The projection angle θ corresponds to the angle of the exit path38of needle wire32relative to distal tip22(e.g., the angle of the tissue track). Catheter34and distal tip22can be configured such that the projection angle can be selectively adjusted. For example, catheter34can comprise a resilient section34bnear distal end34a that is curved along the longitudinal axis of catheter34in a preformed shape. When disposed within catheter20, curved section34bis held in a less curved configuration by sidewall52of catheter20. However, by advancing catheter34in a distal direction, distal end34abecomes adjacent side aperture21and the constraint by sidewall52is reduced and the curved section34badopts a more curved or less constrained configuration. As distal end34aprogressively extends through side aperture21, the projection angle θ increases. In this manner, catheter34moves through a range of projection angles θ as the length of catheter34extending from side aperture21is increased or decreased. In some embodiments, the length (dimension along longitudinal axis Y) of side aperture21can be such that the constraint on catheter34is sufficiently reduced and the distal end34ais able to advance at an angle through side aperture21and not intersect (e.g., clear or not get hung on) sidewall52.

In some embodiments, catheter34is configured not to rotate (e.g., spin) within the lumen of catheter20. This restraint on rotational movement allows for the inner curved surface of curved section34bto remain facing in the direction of side aperture21. This can assist in the reliability of the exit of catheter34through the side aperture. One mechanism for restraining rotation within the lumen of catheter20is to have a channel longitudinally disposed in surface of catheter34that receives (e.g., interlocks with) a rigid protrusion that is disposed in handle28or on the luminal surface of catheter20such that longitudinal movement is not restrained by this mechanism, only rotational movement.

In some embodiments, particularly those that are used to penetrate an occlusion, catheter20can be configured to be sufficiently push-able (in a proximal-distal direction) and/or torque-able to allow distal tip22to be forced into a vessel occlusion (e.g., a thrombus). In some embodiments, catheter system12is configured such that the distal tip22can penetrate a vessel occlusion without deflection. In some embodiments, an appropriate value of bending stiffness can be between 30-60 (pounds force) times (inches squared) (e.g., about 30, 35, 40, 45, 50, 55, or 60 (pounds force) times (inches squared)). For example, a stainless steel tube with an inside diameter of 0.074 inches and outside diameter of 0.094 inches would be sufficient for this purpose. However it is understood that any variety of materials with various wall thicknesses can be pushed and/or torqued to force distal tip22into an occlusion. Other embodiments can comprise a polymeric tube. Such tubes may comprise higher stiffness braided or coiled materials like metals embedded in the polymer.

The magnitude of the forces required can also depend onthe “sharpness” of the distal tip22and the overall diameter. In some embodiments, the tip can be blunted distal end or where the transverse cross-sectional area of the distal end22bis at least 1.5× the area of the aperture29. In other embodiments, the tip can have a distal end that tapers toward aperture29or where the transverse cross-sectional area of the distal end22bis less than 1.5× the area of the aperture29.

Needle wire32can be configured to penetrate a muscletissue and/or thrombus at a distal end32awithout deflection. For example, needle wire32can comprise a trocar-type tip or sharp dissection tip at distal end32a. Such tip can be blunted, flat and angled, conical, or pyrimidal in shape. Needle wire32can also have a bending stiffness sufficient to penetrate a tissue without deflection. Suitable needle wire materials can include any medical grade material that can provide the material properties needed to perform the above function, e.g., steel, titanium (e.g., titanium alloy or nitinol), or the like.

In some embodiments, the needle wire32is made of nitinol with 55-57% nickel and 43-45% titanium. For example, nitinol can comprise the following composition (in wt %):

Chemical Composition(reference ASTM F2063)wt %Nickel (nominal)55.96Titanium43.98Carbon0.025Cobalt0.00033Copper0.00038Chromium0.00024Hydrogen0.0001Iron0.0094Niobium<0.00002Oxygen0.0288

In some embodiments, the diameter of needle wire 32 can be between 0.02 in. to 0.03 in., e.g., 0.020 in., 0.021 in., 0.022 in, 0.023 in, 0.024in., 0.025 in., 0.026 in., 0.027 in., 0.028 in., 0.029 in., or 0.030 in.

In some embodiments, needle wire32can be a drawn filled tube wire comprising a radiopaque core. In some embodiments, the outer sheath is nitinol. In some embodiments, the core can be at least located on the distal end and not extending the entire length.

Catheter system12can further comprise handle28. A magnified, isolated, and exterior view of handle28is provided in FIG. E and a cross-sectional view is provided inFIG.1F. In embodiment shown, handle28is approximately cylindrical with a central axis Y. Handle28can be configured to axially rotate distal tip22of catheter20, catheter20, and/or catheter34. In some embodiments, handle28is configured such that its axial rotation axially rotates catheter20and/or catheter34. This motion facilitates the rotational alignment of distal tip22relative to a radiographic detector as described above.

Handle28can also be configured to advance catheter34through catheter20and out of side aperture21. In the embodiment shown, rotary knob16is configured to turn in a clockwise and/or counter clockwise direction thereby advancing and/or retracting catheter34. Handle28also comprises a gauge or scale17that indicates the projection angle θ of catheter34. The position of catheter34and the projection angle θ is displayed on gauge or scale17in handle28. Thus, knob16is configured to adjust the projection angle θ of catheter34and adjust the reading from the scale17. For example, knob16can be configured such that its rotation turns a threaded body19, whereby the threaded body's rotation advances or retracts catheter34depending upon direction of rotation. Knob16can also be configured such that its rotation translates post60within companion slot61, whereby indicating the projection angle based upon the post's position relative to scale17.

Handle28can also be configured to advance and/or retract needle wire32through catheter34and distal tip22. For example, handle28can comprise a wire clamping and propelling mechanism located within the handle28that allows the user to advance the needle wire32out of the handle. Wire clamping and propelling mechanism can comprise a J-arm clamp62coupled to pommel25. Pommel25is moveable with a reciprocating motion (or piston-like motion), as indicated by motion arrow27. Pommel25is coupled to J-arm clamp62that is configured to wedge against needle wire32as the pommel is advanced distally and to release the needle wire upon a return stroke of the pommel. J-arm clamp62is configured to remain stationary while the pommel moves during the return stroke. Pommel25and handle28are configured to support the wire32during the stroke so that needle wire32does not bend or kink. The stroke is relatively fixed so that a user may count the number of pommel strokes to have an estimate of how much needle wire32has been advanced. Retracting needle wire32can occur by proximally pulling the wire.

Handle28can also comprise a releasable locking mechanism66configured to fix the axial position of needle wire relative to handle28so the withdrawal of the handle also pulls the needle wire. When unlocked, needle wire32can move axially relative to handle to facilitate the removal of catheters20and catheter34from body while the needle wire remains in place. Releasable locking mechanism66comprises a toggle switch67to alternate the mechanism between a lock and unlock position.

Referring toFIGS.2A to2C, another embodiment of the catheter system can comprise a distal tip122instead of distal tip22. Distal tip122in the embodiment shown is the same as distal tip22except that a distal portion of sidewall152defines a curved ramp120configured to guide distal end34athrough side aperture121. A portion of sidewall152opposite and proximal to aperture121can also be sloped or ramping. The angle of the slope can align with entrance angle of ramp120. Lumen123is effectively a gap between the sloping surfaces, ramp120and the sloping sidewall152. This gap is sized to accommodate needle wire32. This gap can further be sized so that it does not accommodate catheter34. In some embodiments, distal tip22comprises a concave, straight-sided channel or groove in sidewall that gradually increases in depth in a distal to proximal direction, where the surface of channel defines side aperture21. This embodiment may be used with a catheter34with or without a curved section34b.

In some embodiments, distal tip122comprises a channel that extends from proximal end122ato an intermediate location between proximal end122aand distal end122b. The channel gradually decreases in depth in a proximal-to-distal direction. The base of the channel is curved along its length. Lumen123is in fluid communication with the channel. Proximal end122aof distal tip122is configured to couple (e.g., mate) with distal end18bof shaft18.

Distal tip can further comprise a second side aperture43opposite the side aperture21such that a line transverse to longitudinal axis passes through both apertures21and/or43.

FIGS.3A to3Iillustrate one embodiment of the present methods. Such methods can be performed using catheter systems described herein, but it is understood that the present methods can be performed using any suitable catheter system.FIG.3Ashows a patient10with an occlusion13involving a vessel300in neck region above the level of the superior vena cava (SVC) and the right atrium near reference numeral15. As shown, a distal tip22of catheter20has approached occlusion13.FIGS.3B-3Hare schematic illustrations of a series of process steps, the illustration showing vessel300with a vessel occlusion13and the distal portion of catheter system12.FIG.3Iillustrates that the radiopaque target30placed on the surface of the patient10serves to set a desired exit site40on the skin of the patient and projection angle θ.

A method for gaining access to a vessel (e.g., a vein, central venous vein, right internal jugular, superior vena cava, or other suitable vessel) can comprise applying a radiopaque target30defining a radiolucent area31to the skin of the patient so that the radiolucent area defines a desired exit site40on the skin of the patient (FIG.3A). Catheter system12can then be introduced into the patient in an area remote from exit site40(e.g., femoral vein) and advanced to a desired site in the vasculature (FIG.3B). In the embodiment shown, the desired site is in the vicinity of occlusion13. In some embodiments, an introducer catheter that has a lower stiffness than catheter20and/or catheter system12is first inserted into the vessel (e.g., femoral vein) and serves as a guide for catheter system12.

To facilitate locating the occlusion relative to catheter system12, a contrast agent can be injected into the vasculature and a radiographic instrument can be used to pin point the occlusion and the relative position of distal tip22, which can comprise a radiopaque material. The introducer catheter can also have a radiopaque distal tip so that its location can be ascertained.

Once at the staging area, needle wire32can be advanced through the distal end aperture29of the catheter beyond distal end22band into occlusion13(FIG.3C). In some embodiments, radiographic imaging can be used to determine the depth of penetration into the occlusion. The depth of penetration can depend on the extent of occlusion13. Pommel25can be reciprocated as described above to advance needle wire32. Since needle wire32is not curved like catheter34, it will advance past side apertures (e.g., aperture21,401, and/or42) and through distal end aperture29. Needle wire32once inserted into the occlusion can define the path of catheter20such that when catheter20is advanced distally and pushed into the occlusion, it will follow the path of the needle wire.

Once in position, catheter20is advanced over needle wire32and into occlusion13as well (FIG.3D). Distal tip22can be pushed in to the occlusion by axial (along Y) and/or rotational forces (around Y) applied to handle28attached to the proximal end of catheter20. In some embodiments, radiographic imaging can be used to determine the depth of penetration into occlusion13. The depth of penetration can depend on the extent of occlusion13.

To facilitate rotational alignment of the distal tip, distal tip22can be viewed using a radiographic instrument (such as an x-ray detector, e.g., CT-scanner, fluoroscope, ultrasound detector, or the like) through radiolucent area31of radiopaque target30. Catheter20can be rotated so that side aperture is aligned with or faces radiolucent area31(FIG.3E). The angle of the line extending between detector plane and distal tip22and to the longitudinal axis of patient or catheter (axis Y) can then be ascertained. Such angle substantially corresponds to the projection angle8.

In some embodiments, the detector can be disposed on a C-arm. The angle of the C-arm relative to the patient can be used to determine the projection angle8. Once the desired tip location is achieved, for example, the C-arm cranial angle is observed and it is used to determine the projection angle8. In general, the C-arm is moved to image the tip22through the target30. The angular location of distal tip22is determined by viewing side apertures41and/or42through target30.FIG.4shows a schematic of the radiographic image. As tip22is rotated around its long axis the width and/or opacity of side apertures41and/or42varies and this changing image feature is used to determine the rotational orientation of distal tip22.

FIG.4is a schematic view of a radiographic image that could be observed by a user. Distal tip22has side apertures41and/or42that can be view through the central aperture31of radiopaque target30. The opacity of the apertures41and/or42can vary with the rotation of catheter20. In general, apertures41and/or42will appear widest and/or brightest when one of aperture41and42is facing the central aperture31. A user can advance or retract the tip22and rotate the distal tip22to optimize the exit path. Once the user has positioned the distal tip at the desired position and rotated it to the desired orientation, the projection angle θ can be ascertained from the C-arm. To set the projection angle θ, knob16is turned until the scale17corresponds to the desired projection angle. The angular range can vary between about 10 degrees to 90 degrees, e.g., 15 to 60 degrees as indicated on scale17or any other range between 10 to 90 degrees. The adjustability of the tip combined with the use of fluoroscopic imaging allows a user to precisely position and aim the distal end of the needle wire. This ability to view and direct the needle wire enhances patient safety.

Needle wire32can then be retracted from beyond aperture29into catheter20and into catheter34(FIG.3F). So as to not unduly effect the axial movement of catheter34, the distal end of the needle wire is retracted so that its distal end is disposed in a non-curved portion of catheter34(e.g., not disposed in curved section34b). In some embodiments, the distal end of needle wire32is spaced apart from distal end34aof the catheter34at least a distance that is not impeding the curvature of catheter curved section34b, e.g., a distance of 2mm, 3 mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, or more.

Catheter34can then be advanced a selected distance such that it extends from side aperture at the desired projection angle (FIG.3G). Scale17can be used to ascertain the projection angle. Catheter34positioned at the desired projection angle is aimed at radiolucent area31. Once catheter34is in position, needle wire32can be advanced through catheter34and into tissue, eventually through the skin of the patient adjacent the radiolucent area of the radiopaque target (FIGS.3H and3I). Distal end32aof needle wire32can then be exteriorized to the patient.

With the needle wire32exteriorized as seen in the figure the access provided to the end of the wire allows additional intervention at the exit wound site as described below. For example, a dilation catheter can be coupled to the exteriorized needle wire and the dilation catheter can be drawn into the exit site by pulling on a proximal end of needle wire32thereby forming a dilated tissue track. A guide wire can be inserted into the dilation catheter and a medical device can be advanced over the guide wire along the dilated tissue track and into the vessel.

It should be understood that the foregoing device is broadly usable to establish an access point to a patient's vasculature from the inside out at any desired location. Once the access point has been established, it can be used for any desired medical procedure. For example, pacing leads for pacemakers can be delivered into a vessel after the tissue track has been established, and treatment devices (such as steerable catheters) can be delivered to the vessel through the access point.

The above specification and examples provide a complete description of the structure and use of illustrative embodiments. Although certain embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention. As such, the various illustrative embodiments of the methods and systems are not intended to be limited to the particular forms disclosed. Rather, they include all modifications and alternatives falling within the scope of the claims, and embodiments other than the one shown can include some or all of the features of the depicted embodiment. For example, elements can be omitted or combined as a unitary structure, and/or connections can be substituted. Further, where appropriate, aspects of any of the examples described above can be combined with aspects of any of the other examples described to form further examples having comparable or different properties and/or functions, and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above can relate to one embodiment or can relate to several embodiments.

The claims are not intended to include, and should not be interpreted to include, means-plus- or step-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively.