Patent Application
20200230359
This disclosure relates generally to catheters and, more specifically, to catheters that are defined from hypotubes, or hypodermic tubing. This disclosure also relates to methods for manufacturing catheters and to methods for using catheters.
Standard angiography catheters, which are typically manufactured from thermoplastic materials by extrusion processes, have pressure ratings of about 1,050 psi to about 1,200 psi. The pressures that are used in angiography procedures often approach, and sometimes exceed, the pressure ratings of standard angiography catheters. Thus, the use of standard angiography catheters can be risky, as excessive pressures may cause such catheters to fail and, thus, may injury a subject on whom the angiography procedures is being conducted.
Microcatheters typically have thin walls and small diameters to enable them to navigate tiny veins and other vessels within a subject's body. Microcatheters that are used in cardiovascular applications may have outer diameters (ODs) of less than 6 French (F) (2 mm). Neurovascular microcatheters may have outer diameters as small as 2.3 F (0.77 mm). Because of their thin walls and small outer diameters, pushability, trackability, and torqueability requirements have limited the lengths of microcatheters. Typically, the upper limit on the length of a microcatheter is about 150 cm, with some microcatheters—particularly those with smaller outer diameters—being much shorter. In addition, to provide desired levels of pushability, trackability, and torqueability, microcatheters are typically tapered; stated another, way, the wall thickness and/or outer diameter is typically not uniform along the length of the microcatheter.
Hypotubes, or hypodermic tubes, have been used for a variety of purposes, including reinforcing portions of conventional thermoplastic catheters. A hypotube is a thin walled tube formed from a metal or a metal alloy, such as a stainless steel, a nickel titanium alloy (e.g., nitinol, which stands for Nickel Titanium Naval Ordinance Laboratory; etc.), or the like. Hypotubes are useful for a variety of purposes. In the medical device industry, hypotubes have been manufactured in a variety of lengths and with outer diameters ranging from about 0.120 inch (11 gauge) to 0.005 inch (36 gauge). Among other purposes, hypotubes have been used to facilitate the introduction of catheters through a patient's anatomy.
Medical hypotubes are commonly formed from stainless steel (e.g., 304 stainless steel, 316 stainless steel, 316L stainless steel, etc.). While stainless steel hypotubes may enhance the ability of a catheter to glide (e.g., push, track, and torque) through a subject's anatomy, they are known for their tendency to kink, particularly when forced through tortuous paths. Nitinol has also been used to form hypotubes. While nitinol hypotubes are kink-resistant, they are much more expensive to manufacture (particularly in developmental stages and in small quantities) than stainless steel hypotubes, and still lack sufficient flexibility to enable them to advance through many of the bends that are present in a subject's vasculature.
A catheter according to this disclosure may include one or more hypotubes and a liner. The catheter may be defined primarily by the one or more hypotubes. The hypotube(s) may include flexibility enhancing features that enable the hypotube to be used to at least partially define the catheter. The liner may be associated with the hypotube(s) in a manner that controls the flow of fluids through the walls of the catheter. The catheter may also include a tip at its distal end, as well as a coupling feature (e.g., a luer lock, etc.) at its proximal end.
In some embodiments, a catheter may consist essentially of a hypotube (e.g., a single hypotube, a series of hypotubes, etc.), a liner, and a coupling feature. In other embodiments, a catheter may consist essentially of a hypotube, a liner, a tip, and a coupling feature; such catheters may include one or more non-essential features. In still other embodiments, a catheter may consist of a hypotube, a liner, and a coupling feature or a hypotube, a liner, a tip, and a coupling feature.
The one or more hypotubes may extend along the entire length of the catheter. Alternatively, one or more hypotubes may extend along substantially the entire length of the catheter. As used in reference to the length of one or more hypotubes relative to the length of a catheter, the term “substantially” indicates that one or more distal features of the catheter may extend slightly beyond a distal end of the hypotube, one or more proximal features may extend slightly beyond a proximal end of the hypotube, and/or small gaps may be present between two or more hypotubes that have been arranged in series along the length of the catheter. Further, the term “substantially,” as used in connection with the length of one or more hypotubes relative to the length of the catheter of which the one or more hypotubes are a part, may be quantified as at least 95% of a length of the catheter, as at least 90% of a length of the catheter, as at least 80% of a length of the catheter, or even as at least 75% of a length of the catheter. In a specific embodiment, the catheter may include a single hypotube.
The flexibility enhancing features of a hypotube may impart the hypotube and a corresponding portion of the catheter with a desired amount of flexibility. The configurations and/or positioning of the flexibility enhancing features may determine the flexibility of the hypotube and the catheter.
The flexibility enhancing features of a hypotube may comprise cuts into or through a wall of the hypotube. In some embodiments, the cuts may extend partially around a circumferential location along the length of the hypotube (e.g., around up to about 95% of the circumference of the hypotube, etc.), normal to a longitudinal axis of the hypotube. These types of cuts are referred to as “circumferential cuts.” U.S. Design patent application No. 29/635,209, filed Jan. 29, 2018 (“the '209 Design application) and U.S. Provisional Patent Application No. 62/623,180, filed on Jan. 29, 2018 (“the '180 Provisional Application), the entire disclosures of which are hereby incorporated herein, disclose embodiments of flexibility enhancing features that comprise circumferential cuts.
Another embodiment of flexibility enhancing feature includes one or more cuts that are oriented helically, or that spiral, around at least a portion of a length of the hypotube (i.e., at a non-perpendicular angle to the longitudinal axis of the hypotube). The length of each cut in a helical series of cuts, as well as the distance between helically adjacent cuts located along a given helical path around the circumference of the hypotube, or the length of each solid region between helically adjacent cuts located along the given helical path, may define the flexibility of a portion of the length of the hypotube. Each helically oriented cut may extend partially around the circumference of the hypotube (i.e., have an arc length of less than 2π, or 360°) (e.g., up 95% of the circumference of the hypotube, or have an arc length of up to about 1.9π, or 342°, etc.). In other embodiments, each helically oriented cut may extend completely around the circumference of the hypotube (i.e., have an arc length of 2π, or 360°, or greater) provided that the helical series of cuts does not facilitate extension of a length of the hypotube upon pulling ends of the hypotube in opposite directions or upon holding one end of the hypotube stationary while pulling on the other end of the hypotube. In some embodiments, a flexibility enhancing feature may be defined by a plurality of helical series of cuts that share the same axis, but are angularly translated around the hypotube.
The flexibility of a portion of the hypotube along which a longitudinal series of flexibility enhancing features is located (i.e., along a length of the hypotube) may be defined, at least in part, on the spacing, or pitch, between longitudinally adjacent flexibility enhancing features (e.g., the longitudinal distance between two longitudinally adjacent circumferential cuts; the distance between locations along an element of the hypotube intersected by longitudinally adjacent portions of one or more cuts oriented along a helical path around the circumference of the hypotube; etc.). A portion of a hypotube that includes shorter spacing between adjacent flexibility enhancing features, or a tighter pitch, may be more flexible than a portion of the hypotube that includes greater spacing between adjacent flexibility enhancing features, or a wider pitch. Conversely a portion of a hypotube that includes greater spacing between adjacent flexibility enhancing features, or a wider pitch, may be stiffer than a portion of the hypotube that includes shorter spacing between adjacent flexibility enhancing features, or a tighter pitch.
Various other factors may also determine the flexibility one or more flexibility enhancing features impart to a portion of a hypotube and, thus, to a corresponding portion of a catheter of which the hypotube is a part. As an example, the flexibility provided by a cut (e.g., a circumferential cut, a helically oriented cut, etc.) or a series of cuts (e.g., a circumferential series of circumferential cuts (i.e., a series of cuts arranged around a circumferential location around the hypotube and along the length of the hypotube, normal to its longitudinal axis); a helical series of helically oriented cuts; etc.) may be a function of the length(s) of the (series of) cut(s) relative to the distance around the circumference, as well as a function of the number of solid sections (e.g., one solid section when a single cut extends around a portion of a circumference of the hypotube; two solid sections between adjacent ends of a series of two cuts extending around different portions of the circumference of the hypotube; etc.) and/or the length of each solid section between circumferentially or helically adjacent cuts. In addition, when helically oriented cuts are used to define flexibility enhancing features of a hypotube, flexibility of a portion of the hypotube may be tailored by positioning cuts of different handedness (i.e., left-handedness, right-handedness), or chirality, adjacent to one another.
In some embodiments, the hypotube and the catheter may have different flexibilities at different locations along their lengths. Different types and/or arrangements of flexibility enhancing features at different locations along the length of the catheter may impart those different locations with different flexibilities. As a nonlimiting example, the flexibility enhancing features of a hypotube located at proximal and intermediate locations along the length of the catheter may impart the proximal and intermediate portions of the catheter with sufficient flexibility to enable these portions to extend along the curves and/or bends of pathways through the body, while imparting the proximal and intermediate portions of the catheter with sufficient stiffness to enable them to transmit a distally oriented pushing force to a distal portion and a distal end of the hypotube and, thus, to a distal portion and a distal end of the catheter. Stated another way, flexibility enhancing features that are to be located along the proximal portion and the intermediate portion of a catheter may impart these portions of the catheter with a desired amount of “pushability.” The flexibility enhancing features of a hypotube located at a distal portion of the catheter may render the distal portion of the catheter even more flexible, imparting the distal end of the catheter with the ability to navigate tortuous vasculature, or “trackability.”
Other types of features may also be defined in a hypotube of a catheter according to this disclosure. As a nonlimiting example, a portion of a length of a hypotube may include features that enable expansion and, optionally, resilient contraction, of a diameter (including, for example, both the inner diameter (ID) and the outer diameter) of the hypotube. Examples of such features are disclosed by U.S. patent application Ser. No. 16/174,205, filed on Oct. 29, 2018 (“the '205 application), U.S. Provisional Patent Application No. 62/735,110, filed on Sep. 22, 2018 (“the '111 Provisional Application), U.S. Design patent application No. 29/625,044, filed on Nov. 6, 2017 (“the '044 Design application), U.S. Design patent application No. 29/670,032, filed on Nov. 13, 2018 (“the '032 Design application), and U.S. Design patent application No. 29/670,041, filed on Nov. 13, 2018 (“the '041 Design application), the entire disclosures of which are hereby incorporated herein. Such expandable features and/or other types of features that are defined in a hypotube may be positioned along at a distal portion of the catheter of which the hypotube is a part (e.g., adjacent to a distal end of the catheter, etc.). Alternatively, or in addition, expandable features or other features defined in a hypotube may be positioned at an intermediate location along the length of the catheter of which the hypotube is a part and/or along a proximal portion of the catheter of which the hypotube is a part.
In a specific embodiment, a catheter according to this disclosure may be most flexible at its distal end, include features that enable radial expansion of the catheter along at least a portion of a distal region, and provide for some flexibility, as well as pushability, along its intermediate and proximal portions.
The liner of a catheter according to this disclosure may control the flow of fluids through the walls of the catheter. In addition, the interior surface of a liner that covers the interior surface of the wall of the hypotube may be smoother, or more lubricious, than the interior surface of the wall of the hypotube. The increased smoothness provided by an interior liner may increase the ease with which a catheter to pass over a guide wire, increase the ease with which other instruments may be introduced into and removed from a subject's body through the catheter, and increase the smoothness with which fluids and other materials flow through the lumen of the catheter. A configuration of the liner (e.g., the material or materials from which it is made, its thickness, its positioning on the hypotube(s), etc.) may dictate how the liner affects the flexibility of the hypotube(s) of the catheter and, thus, the flexibility of the catheter. In some embodiments, the liner may have a configuration that minimizes its impact on the flexibility of the hypotube(s) and, thus, on the flexibility of the catheter, while preventing fluids from flowing through the catheter wall at unintended locations along the length of the catheter. The liner may also have sufficient flexibility, stretchability, and/or resilience to accommodate other features of the hypotube, including, without limitation, features that enable expansion of a portion of the hypotube (e.g., to enable an expandable section to expand, and then facilitate contraction of the expandable portion to its original diameter or substantially to its original diameter (accounting for minor stretching).
The liner may coat an interior surface (i.e., a lumen) of a wall of a hypotube of the catheter, an exterior surface of the wall of the hypotube, or the catheter may include an interior liner on the interior surface of the wall of the hypotube and an exterior liner on the exterior surface of the wall of the hypotube. Each liner may extend along an entire length or substantially an entire length of the catheter (in this context, the term “substantially” has the same meaning as provided previously herein with respect to the portion of the length of a catheter along which a hypotube or a series of hypotubes extends). As another alternative, the liner may include a collection of plugs that fill and seal flexibility enhancing features (e.g., cuts, etc.) along the hypotube (e.g., all of the flexibility enhancing features of the hypotube, selected flexibility enhancing features of the hypotube, etc.) without extending substantially across solid regions of the hypotube (the term “substantially” being used in this context in recognition of the possibility that the material that forms each plug may extend onto surfaces of the solid regions that are located adjacent to a cut within which a plug resides).
A catheter according to this disclosure may have a uniform profile or a substantially uniform profile along its entire length. “Substantially,” as used in reference to the uniform profile of the catheter, may account for acceptable manufacturing tolerances in the outer diameter and outer surface of a hypotube (e.g., in embodiments where the liner of the catheter is located on the interior surface of the wall of the hypotube). In embodiments where the catheter includes an external liner, a “substantially” uniform profile may account for acceptable tolerances in the external liner (e.g., in the wall thickness of the external liner as it is manufactured separately from the hypotube; in variations in the wall thickness of a separately manufactured hypotube as it is introduced over and secured to (e.g., by shrinking, etc.) the hypotube; in variations in the thickness of an external liner that is formed on the outer surface of the wall of the hypotube; etc.). A “substantially” uniform profile may also account for slight variations to the profile that may occur under ordinary conditions (e.g., manufacture, packaging, transportation, storage, use, etc.), during which changes in environment (e.g., temperature, humidity, etc.) may affect the materials from which the catheter, including its hypotube(s) and liner(s), are formed.
In a method for manufacturing a catheter, a hypotube of a desired material and dimensions (e.g., outer diameter, inner diameter, etc.) is selected. Flexibility enhancing features are defined at desired locations along a portion of the hypotube that is to be used to define the catheter. Other features may also be defined at desired locations along the length of the hypotube. Without limitation, flexibility enhancing features and any other features may be defined in the hypotube by laser cutting processes.
Once the flexibility enhancing features and any other features have been defined in the hypotube, a liner may be applied to the hypotube. In some embodiments, the liner may reside on the interior surface of a wall of the hypotube, which defines a lumen of the hypotube. As a nonlimiting example, the liner may comprise a preformed tube with outer cross-sectional dimensions, taken normal to a longitudinal axis of the liner, that enable it to be received by the inner diameter, or lumen, of the hypotube. Such a liner may comprise a material that enables it to expand until an outer surface of the liner abuts and engages the interior surface of the wall of the hypotube (e.g., polytetrafluoroethylene (PTFE), such as the material marketed by The Chemours Company of Wilmington, Del. under the TEFLON® trademark), etc.). Once the liner is positioned within desired locations along the length of the hypotube, the liner may be subjected to processes that will cause it to expand into, or to fit, the interior surface of the wall of the hypotube, thereby securing the liner to the interior surface of the wall of the hypotube.
In other embodiments, the liner may comprise a preformed tube of a contractible, or shrinkable, material (e.g., a heat shrinkable material, such as polyethylene terephthalate (PET); etc.) with a lumen having cross-sectional dimensions, taken normal to a longitudinal axis of the liner, that enable it to receive the outer diameter of the hypotube. The liner may be cut to a desired length, and the hypotube may be introduced into the lumen of the liner. Once the liner is positioned over desired locations along the length of the hypotube, the liner may be subjected to processes that will cause it to contract, or shrink, onto the hypotube, thereby securing the liner to an exterior surface of the wall of the hypotube.
Other techniques for forming internal liners, external liners, and other configurations of liners that reinforce and/or control the passage of fluids through flexibility enhancing features and/or any other features that have been defined in the hypotube may also be used in manufacturing a catheter according to this disclosure.
The hypotube may be cut to a desired length prior to forming flexibility enhancing features and any other features, prior to assembling the liner with the hypotube or forming the liner on the hypotube, or once the liner has been applied to the hypotube. In some embodiments, a taper may be defined at the distal end of the hypotube (e.g., by altering the distal end of the hypotube, etc.) or provided at the distal end of the hypotube (e.g., by coupling a distal tip to the distal end of the hypotube, etc.). Such a taper may, by way of example only, be oriented at an angle of up to about 5° to the longitudinal axis of the hypotube.
A catheter according to this disclosure may also include a tip at its distal end. The tip may be formed or secured to a distal end of a hypotube of the catheter in a manner that mechanically interlocks the tip to the distal end of the hypotube.
Other aspects of the disclosed, subject matter, as well as features and advantages of various aspects of the disclosed subject matter, should become apparent to those of ordinary skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims.
In the drawings:
Along its length, the catheter 10 includes a distal end 20, a distal portion 24, an intermediate portion 26, a proximal portion 28, and a proximal end 29. As shown in
The intermediate portion 26 of the catheter 10, which may comprise a majority of the length of the catheter 10, is configured to enable advancement of the distal end 20 and/or the distal portion 24 of the catheter 10 through the subject's body B to the target site T, to reside within the body B of the subject once the distal end 20 and/or distal portion 24 has been advanced to the target site T, to enable further movement of distal end 20 and the distal portion 24 relative to the target site T, and to enable removal of the catheter 10 and anything carried thereby (e.g., tissue samples, debris, devices, etc.) from the body B of the subject. During advancement and removal of the catheter 10, a healthcare professional may hold the intermediate portion 26 at one or more locations to respectively push the catheter 10 into the subject's body and pull the catheter 10 out of the subject's body B.
The proximal portion 28 of the catheter 10 is configured to reside outside of the subject's body B during advancement, use, and removal of the catheter 10. A proximal end 29 of the proximal portion 28 of the catheter 10 may have a configuration that enables it to couple to one or more devices D that are to be used externally by a healthcare professional to perform one or more procedures at a target site T (or a plurality of target sites T) within the subject's body B.
As shown in
Flexibility enhancing features 50d, 50i, and 50p of the hypotube 30 are respectively located at the distal portion 44, the intermediate portion 26, and the proximal portion 28 of the embodiment of catheter 10 depicted by
The cut that defines a flexibility enhancing feature 50d, 50i, 50p may comprise a circumferential cut or a helically oriented cut. A circumferential cut may be oriented normal to a longitudinal axis of the hypotube 30, and may extend partially around the circumference of the hypotube 30 (e.g., up to about 95% of the circumference of the hypotube, etc.).
Solid regions between ends of adjacent cuts 51 may define a spine 52 of a flexibility enhancing feature 50d, 50i, 50p. The spine 52 may be oriented helically as shown in
The orientation of a cut 51 through the through the wall 40 of the hypotube 30 may be perpendicular to a tangent to the outer surface 42 of the wall 40 (i.e., it may extend the shortest possible distance through the wall 40, i.e., straight through the wall). Alternatively, a cut 51 that forms a flexibility enhancing feature 50d, 50i, 50p (each of which may also be referred to as a flexibility enhancing feature 50) may extend through the wall 40 at a non-perpendicular angle to a tangent to the outer surface 42 of the wall 40 (i.e., diagonally).
Each cut 51 may be performed by any of a variety of suitable processes, including, without limitation, by laser cutting techniques. In some embodiments, a laser beam with a nominal width, or kerf, of 0.0012 inch or less may be used. Smaller laser beam widths may be used to cut sharper features. Defocused laser beams with widths of up to about 0.0012 inch may be used to create angled cuts or shaped cuts 51 (e.g., hourglass shaped cuts, etc.), which may define smooth corners at the inner diameter of a catheter 10. The creation of cuts 51 with smooth corners at the inner diameter of a catheter 10 may impart the catheter 10 with internal lubricity, which may enable fluids to flow more freely (e.g., laminar flow, etc.) through a lumen of the catheter 10 and minimize the friction with which other devices, such guide wires, pass through a lumen of the catheter 10.
As
In addition to the spacing, or pitch, between adjacent flexibility enhancing features 50d, 50i, 50p, other factors regarding the lengths, orientations, and positioning (e.g., spacing between a series of circumferentially oriented or helically oriented flexibility enhancing features, etc.) may at least partially contribute to the flexibility and/or rigidity of a part of the hypotube 30.
Without limitation, the flexibility enhancing features 50d, 50i, and 50p may be arranged in a manner similar to that disclosed by the '209 Design application and the '180 Provisional Application. While
In addition to including flexibility enhancing features 50, a hypotube 30 of a catheter 10 (
With returned reference to
As
In the embodiment illustrated by
The flexibility enhancing features 50d′, 50i′, and 50p′ may be arranged along one or more helical, or spiral, paths around the circumference of the hypotube 30′. More specifically, at least some of the flexibility enhancing features 50d′, 50i′, and 50p′ may comprise helical cuts 51′, or spiral cuts, into or through the wall 40′ of the hypotube 30′. A helical cut 51′ may extend around at least a portion of a length of the hypotube 30′ (i.e., at a non-perpendicular angle to the longitudinal axis of the hypotube 30), and may extend partially around the circumference of the hypotube 30′ (i.e., have an arc length of less than 2n, or 360°) (e.g., up 95% of the circumference of the hypotube 30′, or have an arc length of up to about 1.9n, or 342°, etc.) or completely around the circumference of the hypotube 30′ (i.e., have an arc length of 2n, or 360°, or greater), provided that helically arranged series of helical cuts 51′ does not facilitate elongation of the hypotube 30′.
A helical series of helical cuts 51′ may have the appearance of an interrupted helix, or an interrupted spiral. Solid regions between ends of helically adjacent helical cuts 51′ may define a spine 52′ of a flexibility enhancing feature 50d′, 50i′, 50p′. The spine 52′ may be oriented longitudinally, as shown in
Although
Turning now to
An embodiment of a flexibility enhancing feature 150 with a plurality of helically oriented series 153a, 153b, 153c, etc., of cuts 151 may expand when the catheter 100 of which the flexibility enhancing feature 150 is a part is rotated, or torqued, in one direction (e.g., in the direction in which the helices rotate, etc.) and contract upon rotation, or torqueing, of the catheter 100 in the opposite direction (e.g., in a direction opposite from the direction in which the helices rotate, etc.). As the flexibility enhancing feature 150 expands, the cuts 151 may define thread-like ridges, which may impart the flexibility enhancing feature 150 with a screw-like shape that enables it to engage lesions, plaques, or other features that narrow the pathway through a vessel. As the flexibility enhancing feature 150 contracts, the outer diameter of the flexibility enhancing feature 150 may decrease, or tighten, which may improve the profile of the catheter 100 for crossing narrowed locations of a pathway through a vessel.
Another embodiment of catheter 110, which includes a liner 160 on an exterior of one or more hypotubes 30, is depicted by
In the embodiment depicted by
More specifically, the exterior surface 42 of the wall 40 of the hypotube 30 may be exposed at a location that includes operational features 55, 56 (
In other embodiments, such an externally located liner 160 may cover an entire exterior surface 42 of a hypotube 30.
As noted previously herein, standard angiography catheters (which are typically 4 F to 6 F in size (i.e., have an OD of about 0.053 inch or 1.333 mm to about 0.079 inch or 2 mm), have pressure ratings of about 1,050 psi (about 7.25×103 kpa) to about 1,200 psi (about 8.275×103 kpa). Stainless steel hypotubes with the same dimensions have pressure ratings of about 8,500 psi (about 5.85×104 kpa). While cuts in the hypotube may decrease the maximum pressure that can be applied to it from inside its lumen, a catheter according to this disclosure may still have a pressure rating of about 2,000 psi (about 1.4×104 kpa), about 3,000 psi (about 2×104 kpa), about 4,000 psi (about 2.8×104 kpa), about 5,000 psi (about 3.4×104 kpa), or even greater than 5,000 psi (about 3.4×104 kpa). Thus, by being able to withstand increased pressure over a conventional catheter, a catheter that includes a hypotube along substantially all of its length may be safer than a conventional catheter and may provide for increased performance characteristics (e.g., higher fluid flow rates, etc.).
With returned reference to
Once the flexibility enhancing features 50, 50′ and any other features have been defined in the hypotube 30, 30′, a liner 60, 60′, 160 may be applied to the hypotube 30, 30′. With reference to
As a nonlimiting example, the liner 60, 60′ may comprise a preformed tube with outer cross-sectional dimensions, taken normal to a longitudinal axis of the liner, that enable it to be received by the inner diameter, or lumen 46, 46′, of the hypotube 30, 30′. Such a liner 60, 60′ may comprise a suitable polymer (e.g., PTFE, etc.). In some embodiments, the liner 60, 60′ may comprise a material that enables it to expand until an outer surface of the liner 60, 60′ abuts and engages the interior surface 44, 44′ of the wall 40, 40′ of the hypotube 30, 30′ (e.g., ePTFE, etc.). An outer surface of the liner 60, 60′ may be coated with a bond layer (e.g., a layer of polyether block amide (PEBA), available from Akrema S.A. of Colombes, France under the PEBAX® trademark and from Evonik Industries AG of Essen, Germany, under the VESTAMID® E trademark; etc.). The bond layer may be as thin or thinner than the liner 60, 60′ (e.g., 0.0002 inch or thinner).
Once the liner 60, 60′ is positioned within desired locations along the length of the hypotube 30, 30′, the liner 60, 60′ may be subjected to processes that will cause it to expand into, or to fit, the interior surface 44, 44′ of the wall 40, 40′ of the hypotube 30, 30′, which may secure the liner 60, 60′ to the interior surface 44, 44′ of the wall 40, 40′ of the hypotube 30, 30′. As an example, the liner 60, 60′ may be physically pressed against the interior surface 44, 44′ from within the lumen 46, 46′ (e.g., mechanically, with a long balloon, pressure vessel, etc.; under pressure; etc.). As another example, the direction of heat into a liner 60, 60′ made from an expandable material may cause the liner 60, 60′ to expand until sufficient contact is established between the outer surface of the liner 60, 60′ or a bond layer thereon and the interior surface 44, 44′ of the hypotube 30, 30′. Heat may thermally activate a bond layer on the outer surface of the liner 60, 60′, which may enable the bond layer to adhere to or bond with the interior surface 44, 44′ of the hypotube 30, 30′, securing the liner 60, 60′ to the interior surface 44, 44′.
A catheter 10, 10′ with an internal liner 60, 60′ may be manufactured from the outside-in. The inclusion of a liner 60, 60′ within the lumen 46, 46′ of the hypotube 30, 30′ may provide a surface with constant lubricity along a length of the catheter 10, 10′. By using a hypotube 30, 30′ with a liner 60, 60′ in its lumen 46, 46′ to form a catheter 10, 10′, the catheter 10, 10′ may have a small outer diameter (e.g., 6 F or less), an inner diameter that is at least as large as the inner diameter of a comparably sized microcatheter that has been manufactured from a polymer while retaining lubriciousness along its length, and a length that exceeds the length of a comparably sized microcatheter that has been manufactured from a polymer while having desired or required levels of pushability, trackability, and torqueability (e.g., 175 cm for catheters that are smaller than 6 F).
With reference to
With the liner 60, 60′, 160 in place on the hypotube 30, 30′, the hypotube 30, 30′ may be cut to a desired length prior to forming flexibility enhancing features 50, 50′ and any other features 55, 55′, 56, 56′, prior to assembling the liner 60, 60′, 160 with the hypotube 30, 30′ or forming the liner 60, 60′, 160 on the hypotube 30, 30′, or once the liner 60, 60′, 160 has been applied to the hypotube 30, 30′.
In some embodiments, the distal end 20 of the catheter 10, 10′, 10″, 110 may be formed in a manner that preserves the inner diameter of the catheter 10, 10′, 10″, 110 or, more specifically, of its lumen 46, 46′. As an example, the edge of the hypotube 30, 30′ at the distal end 20 of the catheter 10, 10′, 10″, 110 may be smoothed, providing an opening at the distal end 20 that has an inner diameter that is the same as the inner diameter of the lumen 46, 46′.
In other embodiments, a taper may be defined at the distal end of the hypotube 30, 30′ (e.g., by altering the distal end of the hypotube, etc.) or provided at the distal end of the hypotube (e.g., by coupling a distal tip to the distal end of the hypotube, etc.). Such a taper may, by way of example only, be oriented at an angle of up to about 5° to the longitudinal axis of the hypotube. Such a taper may impart the hypotube 30, 30′ and the catheter 10, 10′, 10″, 110 of which the hypotube 30, 30′ is a part with crossability, or the ability to navigate the catheter 10, 10′, 10″, 110 through narrow restrictions in a subject's vasculature.
As an alternative to forming a taper at the distal end 20 of the catheter 10, 10′, 10″, 110, a taper may be provided at the distal end 20 by assembling a tip 70, 70′ with the distal end 20 or by forming a tip 70, 70′ on the distal end 20. For reference in describing these methods,
The tip 70, 70′ may be formed from a suitable polymer by known processes. As an example, a radiofrequency (RF) catheter tipper may be used with a tipping die and a tipping tube to form the tip 70, 70′ on the distal end 32 of the hypotube 30. The tipping tube and the distal end 32 of the hypotube 30 are introduced into the tipping die and the tipping die is heated by the RF catheter tipper. The material from which the tipping tube is formed is at least partially liquefied, and a portion of the tipping material flows into tip engagement features 34, 34′ at or near the distal end 32 of the hypotube 30. The tip engagement features 34, 34′ may mechanically anchor the tip 70, 70′ to the distal end 32 of the hypotube 30.
Tip engagement features 34 may comprise recesses, such as the series of recesses (e.g., dovetail cutouts, etc.) formed in the edge 33 of the distal end 32 of the hypotube 30, and arranged, or extending, around a circumference of the distal end 32 of the hypotube 30, as shown in
Alternatively, the tip 70, 70′ may be formed on the distal end 32 of the hypotube 30 by a suitable molding or reflow process. A mold with a cavity that defines the tip 70, 70′ may also receive a distal portion 36 of the hypotube 30 and position the distal end 32 of the hypotube 30 adjacent to or slightly in the cavity. As a selected tip material (e.g., a polymer, etc.) may then be introduced into the cavity of the mold (e.g., as a tipper tube, in liquefied form, etc.), the liquid tip material may also extend into tip engagement features 34, 34′ in the edge 33 of the distal end 32 of the hypotube 30. As the tip material solidifies, tip material within the cavity of the mold forms the tip 70, 70′, while tip material within the tip engagement features 34, 34′ forms tube engagement features 72 of the tip 70, 70′, mechanically interlocking the tip 70, 70′ and the distal end 32 of the hypotube 30.
The tip 70, 70′ may include an opening with an inner diameter that is the same size as, substantially the same size as, or larger than the inner diameter of the lumen 46, 46′ of the hypotube 30, 30′ or a liner 60, 60′ therein (
Suitable materials for forming the tip 70, 70′ include, without limitation, thermoplastic materials, such as PEBA. In some embodiments, such a tip 70, 70′ may include a radiopaque material, which may eliminate the need for a separate radiopaque marker. As an example, a polymer that has been infused with a radiopaque material, or throughout which particles of the radiopaque material are dispersed, may be used. Without limitation, particles of tungsten (W) may be blended into the polymer (e.g., PEBA, etc.). A specific embodiment of such a material includes 40% PEBA, by weight (w/w), and 60% tungsten, by weight (w/w).
The addition of a tip 70, 70′ to the distal end 32 of the hypotube 30 of a catheter 10 may facilitate advancement of the distal end 32 and, thus, of the catheter 10 along a desired path within a subject's body (e.g., enhance the trackability and/or crossability of the catheter 10, etc.). Interlocking between the tip 70, 70′ and the distal end 32 of the hypotube 30 may enhance torqueability of, or the ability to rotate, the hypotube 30 and the catheter 10 of which the hypotube 30 is a part.
The tip 70, 70′ may be formed or assembled with the distal end 32 of the hypotube 30 in a manner that preserves the inner diameter of the catheter 10 or more specifically, of the lumen 46 of the catheter 10. Thus, the tip 70, 70′ may not extend into the lumen 46 of the catheter 10.
Although the preceding description and the accompanying drawings are limited to a few specific embodiments, the specific embodiments that have been described and illustrated should not be construed as limiting the scope of any of the appended claims. Features from different embodiments may be employed in combination. All additions to, deletions from, and modifications of the disclosed subject matter that fall within the scopes of the claims are to be embraced by the claims.
Claims for the benefit of the Jan. 21, 2019 filing date of U.S. Provisional Patent Application 62/794,976, titled HYPOTUBE CATHETERS (“the '976 Provisional Application”) and the benefit of the Aug. 14, 2019 filing date of U.S. Provisional Patent Application 62/886,363, titled HYPOTUBE CATHETERS (“the '363 Provisional Application”) are hereby made pursuant to 35 U.S.C. § 119(e). The entire disclosures of the '976 Provisional Application and the '363 Provisional Application are hereby incorporated herein.
| Number | Date | Country | |
|---|---|---|---|
| 62886363 | Aug 2019 | US | |
| 62794976 | Jan 2019 | US |
