A medical device such as a catheter may have an elongate shaft that includes a hypotube having a cut formed therein. The elongate shaft may define a lumen that extends within the elongate shaft. A polymer may be disposed over at least a portion of the hypotube. A medical device may include a cut hypotube having a constant pitch and may be configured to reversibly and temporarily alter the pitch of at least a portion of the cut hypotube. In some cases, the medical device may be configured to reversibly and/or temporarily alter a compressive strength of at least a portion of the cut hypotube.

SUMMARY OF THE SYSTEM

The instant apparatus and system, as illustrated herein, is clearly not anticipated, rendered obvious, or even present in any of the prior art mechanisms, either alone or in any combination thereof. A versatile system, method and series of apparatuses for creating and utilizing a hypotube system as part of a delivery device and other like systems is disclosed.

The present system pertains to improved medical devices providing advantages in flexibility, strength and other desired properties. Accordingly, an illustrative but non-limiting example of the present system may be found in a medical device such as a catheter that has an elongate shaft that includes a hypotube having cutting formed within the hypotube. The elongate shaft may define a lumen that extends within the elongate shaft.

Another illustrative but non-limiting example of the present system may be found in a medical device that includes a hypotube middle liner, a Teflon inner liner, and a powdered polymer coat. Thus, herein achieved is a system of a hypotube incorporated within a catheter to allow for a larger interior diameter working lumen than conventional designs while still maintaining the stiffness properties of the catheter shaft. These hypotube systems may be utilized in Neurovascular, Peripheral and cardiovascular procedures and/or in any other nonvascular procedure requiring a catheter which offers the largest interior diameter profile while also providing the lowest outer diameter profile possible.

It is an object of the present system to provide a hypotube with a customizable stiffness profile along its length to allow for a multitude of applications.

It is further object of the present system to provide a hypotube with a low friction interior surface.

It is a further object of the present system to provide a hypotube encapsulated in a dip coated polymer allowing for lower wall thickness.

It is a further object of the present system to provide a hypotube with a low wall thickness to allow for easier maneuverability and increased usages during medical procedures.

It is a further object of the present system to maintain superior stiffness properties overtime while exposed to the internal body temperature of an individual during a medical procedure.

It is a further object of the present system to provide a hypotube with a stiff proximal region to allow for increased pushability of a catheter incorporating the hypotube system.

It is a further object of the present system to provide a hypotube with a soft distal region for increased maneuverability during a medical procedure.

It is a further object of the present system to provide a hypotube for use in a variety of catheter applications.

Therefore, through the construction of the hypotube it is possible to achieve superior stiffness and support while also eliminating any issues relating to the softening of the hypotube body as a function of time exposed to an individual's internal body temperature during a medical procedure. A user may choose any cut pattern to provide the stiffness profile desired and achieve this stiffness with a wall thickness that is thinner than conventional braided or coiled constructions.

Further, the hypotube catheter shafts may be made from nitinol. Shafts made from nitonol tend to be an excellent choice for minimally-invasive catheter procedures because they can be designed with varying degrees of trackability and torque. This design flexibility allows the hypotube to be made to resist kinking in the most intricate, demanding medical procedures.

There has thus been outlined, rather broadly, the more important features of a hypotube construction and incorporation into a delivery device so the description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the system that will be described hereinafter and which will form the subject matter of the claims appended hereto.

These together with other objects of the system, along with the various features of novelty, which characterize the system, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the system, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the system.

While the system is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the system to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the system.

DETAILED DESCRIPTION OF THE SEVERAL EMBODIMENTS

For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the terms “about” may include numbers that are rounded to the nearest significant figure.

The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The drawings, which are not necessarily to scale, depict illustrative embodiments of the claimed system.

FIG. 1Aillustrates a simple cross-sectional view shown lengthwise of a hypotube10, wherein the hypotube10preferably is utilized in construction with micro-catheter designs (seeFIG. 3). In one embodiment, the hypotube system10comprises a pair of polymer layers12A and12B, wherein the pair of polymer layers12A and12B surround a hypotube body14. Additionally, a liner16may be secured against an inside surface (seeFIG. 1B) of the hypotube body14. In one embodiment, a first polymer layer12A encapsulates the inside surface of the hypotube body14, while a second polymer layer encapsulates an outside surface (seeFIG. 1B) of the hypotube body14. Furthermore, the liner16is secured against the second polymer layer12B on the inside surface of the hypotube body14.

The polymer layers12A and12B may be formed of any suitable polymeric material. In particular embodiments, the polymer layer12is formed of a material such as the ELAST-EON™ materials commercially available from AORTECH BIOMATERIALS, of Australia. The ELAST-EON™ materials generally are polyurethanes that include a polysiloxane component. While these materials encompass both elastomeric and non-elastomeric polymers, elastomeric polymers are useful in particular embodiments of the present system. In some instances, useful elastomeric polymers may exhibit an elongation of at least about 500 percent.

FIG. 1Billustrates a more detailed cross-sectional view shown lengthwise of a hypotube,10. The hypotube system10comprises the pair of polymer layers12A and12B, wherein the polymer layers12A and12B surround the hypotube body14. In another embodiment, a cut pattern28(seeFIGS. 4B-4Dfor more detail) may be formed within the hypotube body14; the cut pattern28may be cut in a number of ways to provide a desirable stiffness profile to a user. Different cut patterns may impart different degrees of support at specific sections along the length of the hypotube10. Types of cut patterns28include, but are not limited to, C-cuts, spiral cuts, interrupted spiral cuts which may be varied numerous ways in a cut pitch or cut density to provide any stiffness profile desired in a catheter.

The hypotube10preferably comprises a proximal region30defining a proximal end32, and a distal region34defining a distal end36. The hypotube10may be cut in any number of ways to provide a desirable stiffness profile over an entire working length40of the hypotube10. The cut pattern28may comprise any number of variations to impart different degrees of support at specific sections along the length40of the hypotube10.

The hypotube body14further comprises an inside surface42A and an outside surface42B; preferably the inside surface42A faces a lumen44formed by the hypotube body14. In one embodiment, the liner16is placed against the inside surface42A of the hypotube body14and secured in place by the first polymer layer12A. The liner16may be a low friction material which provides a low friction interface desired to allow a variety of medical devices to be pushed through the hypotube10during a medical procedure.

In one embodiment, the liner16is a material which includes, but is not limited to: Teflon, PD Slick (i.e. a blend of PTFE and polyimide), a high density polyethylene or any other similar low friction materials. PTFE, polytetrafluoroethylene may be used as a lubricant-like material and reduce friction. When used in hypotube structures, PTFE has a low coefficient of friction for ease of navigation in intravenous procedures. A wide variety of coating technologies are available to maximize hypotube trackability including the PTFE coatings and polymer jackets.

In yet another embodiment, the hypotube10further comprises a pair of dip-coated polymer layers12A and12B, wherein the polymer layers12A and12B is preferably a solution that encapsulates a plurality of interstices50(seeFIG. 4) located on the inside surface42A and outside surface42B of the hypotube body14created by the cut pattern28. Furthermore, the polymer layers12A and12B preferably serve the dual purpose of providing a smooth outside surface42B to the hypotube10, while at the same time securing the liner16in place against the inside surface42A of the hypotube body14.

FIG. 2illustrates a cross-sectional view along line5-5of the hypotube10shown inFIG. 1, wherein the hypotube10possesses an inside diameter20and a corresponding outside diameter18. In practice, medical practitioners desire a larger inside diameter20working lumen44while keeping the outside diameter18of the hypotube10as close to the inside diameter20as possible to create a larger area for medical devices to pass through. The problem with this type of construction utilizing traditional catheter designs is through the expense of wall thickness which in turn affects shaft stiffness. Typically the longer a medical procedure case takes, traditional braided polymer catheters soften and lose their support properties.

The instant system eliminates these issues by providing a hypotube10construction, wherein the thickness of the inside diameter20and the outside diameter18is nearly identical, while being able to possess superior stiffness and flexibility properties.

Preferably, the liner16possesses a thickness in the range of 0.00025 inches to 0.001 inches, and more preferably possesses a thickness of one-one thousandth of an inch. Moreover, in one embodiment, the diameter of the lumen44is roughly seven-one hundredths of an inch; therefore, in practice the inside diameter20of the hypotube body14is almost identical to the diameter of the lumen44as the thickness of the liner16and the polymer layer12between the liner16and the inside surface42A of the hypotube body14is minimal. In a preferred embodiment, the ratio of the thickness of the outer diameter18to the thickness of the inner diameter is in the range of 1.15:1 to 1.5:1.

In further embodiments, the hypotube may possess a range in the stiffness profile wherein the stiffest profile would equate to an uncut stainless steel tube (located near the proximal region30) to as flexible as desired, which may be a function of the softest durometer polymer utilized (around 65 A on the durometer scale) combined with a high density cut pattern28(located near the distal region34) which the hypotube body14may tolerate (distally34). In yet another embodiment, the stiffness profile of the hypotube10may be in the range of 65 A to 75 D in accordance with the durometer scale as known in the art.

In further embodiments of the hypotube10, the thickness of the hypotube body14may be in the range of one one-thousandths (0.001) of an inch to three one-thousandths (0.003) of an inch. Additionally, the first polymer layer12A preferably includes a thickness in the range of five ten-thousandths (0.0005) of an inch to fifteen ten-thousandths of an inch (0.0015), and more preferably one one-thousandth of an inch (0.001) to fifteen ten-thousandths (0.0015) of an inch. Moreover, the second polymer12B preferably includes a thickness in the range of three ten-thousandths (0.0003) of an inch to three thousandths (0.003) of an inch. Lastly, the lumen44of the hypotube body14may have an inner diameter20in the range of thirty-four ten-thousandths (0.0034) of an inch to thirty-six ten-thousandths (0.0036) of an inch; conversely the outer diameter18of the hypotube10may be in the range of forty-one ten thousandths (0.0041) of an inch to forty-three ten thousandths (0.0043) of an inch.

In one embodiment, the hypotube body14is preferably constructed of a material including, but not limited to stainless steel, cobalt chrome, nitinol, and any similar metallic compound which is not polymeric in nature. In other embodiments, part or all of the hypotube body may be formed of a metal or a metal alloy. Some examples of suitable metals and metal alloys include stainless steel, such as 304V, 304L, and 316L stainless steel; alloys including nickel-titanium alloy such as linear elastic or superelastic (i.e. pseudoelastic) nitinol; nickel-chromium alloy; nickel-chromium-iron alloy; cobalt alloy; tungsten or tungsten alloys; MP35-N (having a composition of about 35% Ni, 35% Co, 20% Cr, 9.75% Mo, a maximum 1% Fe, a maximum 1% Ti, a maximum 0.25% C, a maximum 0.15% Mn, and a maximum 0.15% Si); hastelloy; monel 400; inconel 825; or the like; or other suitable material. The particular material used can be chosen in part based on the desired characteristics of the hypotube body14, for example flexability, pushability, torqueability, and the like.

In even further embodiments, the hypotube body may be formed from a superelastic or linear elastic nickel-titanium alloy, for example, linear elastic or superelastic (i.e. pseudoelastic) nitinol.

Within the family of commercially available nitinol alloys, is a category designated “linear elastic” which, although is similar in chemistry to conventional shape memory and superelastic varieties, exhibits distinct and useful mechanical properties. By skilled applications of cold work, directional stress, and heat treatment, the wire is fabricated in such a way that it does not display a substantial “superelastic plateau” or “flag region” in its stress/strain curve. Instead, as recoverable strain increases, the stress continues to increase in an essentially linear relationship until plastic deformation begins. In some embodiments, the linear elastic nickel-titanium alloy is an alloy that does not show any martensite/austenite phase changes that are detectable by DSC and DMTA analysis over a large temperature range.

Preferably, the hypotube body14is constructed of a higher modulus metal which allows for a thinner hypotube body14construction which may be utilized to achieve a higher stiffness profile of the hypotube10. Furthermore, the hypotube body14may comprise a cut pattern28including, but not limited to C-cut, spiral cut, interrupted spiral, and any combination/blend thereof. Additionally, the cut pattern28may vary along the length40of the hypotube body14such that the spacing of the cut pattern28in one embodiment may be equidistantly disposed along the length40, whereas in another embodiment the spacing between the cut pattern28may be random or in a specified pattern that provides for unequal spacing. Additionally, the cut pitch and/or cut density of the cut pattern28may vary along the length40of the hypotube body14to incorporate various stiffness profiles depending on the medical procedure and requirement by physicians. Lastly, the polymer layers12A and12B may be a polymer including, but not limited to PEBAX, nylons, polyurethanes and other polymers that possess similar properties. In one embodiment, the polymer layers12A and12B may be a material that may be dissolved in solution and subsequently applied to the hypotube body14and liner16via a dip-coating process.

FIG. 3illustrates a known in the art catheter system60which may incorporate the hypotube10of the present system; in this embodiment the catheter system60comprises a catheter62(shown schematically), a stent64, a guidewire66, and an expandable balloon68, with the balloon68in an inflated or deflated configuration. In a deflated or delivery configuration, the balloon68and stent64will have an outer diameter close to the outer diameter of a shaft70of the catheter62. The catheter62includes a distal guidewire portion72at a distal end76of the catheter62and a proximal guidewire portion74proximal of the balloon64.

FIG. 4Aillustrates an enlarged cross-sectional view taken from the dotted circle inFIG. 1B. The hypotube10further comprises a pair of polymer layers12A and12B, wherein the polymer layers12A and12B are preferably dip-coated and is a solution that encapsulates a plurality of interstices50created by the cut pattern28.

The hypotube system preferably possesses a desired cut pattern28(seeFIG. 1B) to provide the stiffness profile wanted and to achieve this stiffness with a wall thicknesses that is thinner than conventional braided or coiled constructions. Types of cut patterns28include, but are not limited to, C-cuts, spiral cuts, interrupted spiral cuts which may be varied numerous ways in a cut pitch or cut density to provide any stiffness profile desired in a catheter. Cuts used in an embodiment of the present system may be constant or varied depending upon the stiffness transition characteristics desired. For example, the pitch may be increased for more flexibility or decreased for less flexibility. Further, the cut pattern may extend partially through or all the way through the hypotube body. As stated, the cut pattern creates a set of interstices50filled with a low stiffness polymer that gives a smooth outer surface to the laser cut hypotube while at the same time securing a liner16in place. In this embodiment, the first polymer layer12A and the second polymer layer12B encapsulate the plurality of interstices50created by the cut pattern28in the hypotube body14. In alternate embodiments, the cut pattern28and corresponding interstices50may be located on the outer surface42B of the hypotube body14only, or the inside surface42A of the hypotube body14only, so some combination thereof.

Additionally, the cut pattern28of the hypotube10may vary depending on the medical procedure involved and utilizing the hypotube10. For example, the cut pattern28may vary as a function of the size of the medical device, location of the anatomy of a patient, and the length required to reach the target location from the insertion point.

One important element of the hypotube10described herein, is the ability to cut any stiffness profile over any discreet length, short or long. As such, it may be possible to start on the distal end of the hypotube body and go from stiff to soft and stiff again or any other permutation of those until the proximal end. However, the type of cut pattern28employed, and in turn the associated stiffness profile, may be anatomy specific and application specific. Moreover, in one embodiment, the maximum cut density per unit length will be dictated by how much the hypotube10being cut is affected by the heat generated by a laser, however in one embodiment a one hundredth (0.01) inch of gap separation in the consecutive cuts may be utilized.

FIG. 4Billustrates a perspective view of one embodiment of the hypotube body14. In this embodiment the hypotube body14has a plurality of external grooves202that extend from a main body200of the hypotube body14. In this embodiment the grooves202are externally oriented, however in other embodiments they may be internally oriented as depressions. In this embodiment the external grooves202are vertically oriented, however in other embodiments they may be oriented diagonally, horizontally or in a broken pattern.

FIG. 4Cillustrates a perspective cutaway view of an embodiment of the hypotube body14with a polymer coating204. In this embodiment the polymer coating204fills a plurality of cavities201between the external grooves202, however in other embodiments the polymer coating204may cover the entire hypotube body14.

FIG. 4Dillustrates a perspective view of an embodiment of the hypotube body14. In this embodiment the hypotube body14has a plurality of diagonal grooves208that extend from the main body200of the hypotube body14. In this embodiment the diagonal grooves208are externally oriented however in other embodiments they may be internally oriented as depressions. In this embodiment the diagonal grooves208are diagonally oriented, however in other embodiments they may be oriented vertically, horizontally or in a broken pattern.

FIG. 4Eillustrates a perspective cutaway view of an embodiment of the hypotube body14with a polymer coating210. In this embodiment the polymer coating210fills a plurality of diagonal cavities207between the plurality of diagonal grooves208, however in other embodiments the polymer coating210may cover the entire hypotube body14.

FIG. 4Fillustrates a perspective view of an embodiment of the hypotube body14. In this embodiment the hypotube body14has a plurality of diagonal cuts214that extend from the main body200of the hypotube body14. In this embodiment the plurality of diagonal cuts214are externally oriented however in other embodiments they may be internally oriented as depressions. In this embodiment the plurality of diagonal cuts214are diagonally oriented, however in other embodiments they may be oriented vertically, horizontally or in a broken pattern.

FIG. 4Gillustrates a perspective cutaway view of an embodiment of the hypotube body14with a polymer coating216. In this embodiment the polymer coating210fills the plurality of diagonal cuts214and the entire hypotube body14.

FIG. 5illustrates a longitudinal cross-sectional view of a portion of the catheter62illustrated inFIG. 3, incorporating yet another embodiment of the hypotube system. The catheter shaft70includes a hypotube shaft80including a proximal portion82and a distal portion88, with the proximal82and distal88portions being joined together near the distal end86of the proximal portion and the proximal end84of the distal portion88. An inflation lumen78extends through the hypotube shaft80into an interior of the balloon68. In an exemplary embodiment, the two portions of the hypotube80are joined at a telescoping connection, that is, the distal end86of the proximal portion82is positioned distally of the proximal end84of the distal portion88, and one of the two portions has an outer dimension.

Another advantageous, optional feature of the present system includes that the hypotube80comprises one or more cuts50formed therein, which increases the flexibility of the hypotube in the area of the cut50. By way of example and not of limitation, the shape of the cut50may be C-cut, spiral cut, interrupted spiral cut, as well as other shapes and orientations of one or more cuts50, so that a desired stiffness profile may be achieved by a user of a catheter. Additionally, the cut50, or the density of cuts50, may be non-uniform, and advantageously may be formed so that the configuration of the cut50contributes to the increasing flexibility of the catheter shaft70. The plurality of cuts form a cut pattern28. By way of non-limiting example, a spiral cut, such as that illustrated herein, may be formed, e.g., by laser cutting.

Yet another advantageous, optional feature of the present system is the further inclusion of a polymer jacket92over the hypotube80. By forming the jacket92of a polymer material, the catheter shaft70may be made fluid tight to the inflation fluid passing through inflation lumen78, relatively low friction to assist in passing the catheter62through the vasculature of a patient, and the flexibility of the catheter shaft70may further be modified. More specifically, the jacket92may be formed of a material, and having thicknesses, so that the flexibility of the shaft70increases distally.

In practice, the hypotube10may form a catheter construction in the range of one-and-a-half to twenty French, and more preferably in the range of three to six French. Furthermore, in one embodiment, the proximal region30will possess a stiffer profile in comparison to the distal region34, which will be softer in nature. As such, the stiffer proximal region facilitates better pushability while in turn the softer distal region34assists navigating a vessel tortuosity. However, in alternate embodiments, the stiffness profiles between the proximal end32and the distal end36may comprise an infinite number of profiles depending on the properties required for treating a specific disease where more or less support is required at certain locations over the length of the hypotube10.

In alternate embodiments, the hypotube10in accordance with the present system, may be of any of variety of different catheters. In some embodiments, the hypotube10may be an intravascular catheter; examples of intravascular catheters include balloon catheters, atherectomy catheters, drug delivery catheters, stent delivery catheters, diagnostic catheters and guide catheters. Furthermore, the intravascular hypotube10may be sized in accordance with its intended use. Furthermore, the hypotube10may be utilized in a variety of procedures, including but not limited to: Neurovascular, Peripheral, Cardiovascular, and in any non-vascular procedure requiring a catheter which offers the largest inside diameter of the lumen44while keeping the outside diameter profile low.

Therefore, having the ability to deliver larger lumen devices with superior support profiles, physicians do not need to worry about having to insert a supporting sheath(s) over the guide catheter outside diameter for enhanced support or insert a stiff buddy wire inside the guide lumen to enhance its support. As such, the instant system provides a novel hypotube solution, for use with a variety of micro catheter designs, wherein the hypotube10allows for large catheters to behave as small catheters from a functionality and usage standpoint, and conversely to allow small catheters to behave as large catheters during use.

FIG. 6illustrates one embodiment wherein a balloon with mandrel support guidewire is loaded within the hypotube body. The removable mandrel support guidewire104runs concentrically along the length of a reinforced single lumen shaft and is pushed through the hypotube body14.

In one embodiment, within the hypotube body14is a reinforced single lumen shaft108; a removable mandrel support guidewire104; a bonded balloon106that is deflated; the bonded balloon106may include a bonded tip110and an attached soft atraumatic tip112. The reinforced single lumen shaft108may be comprised of a reinforced polymer outer layer114.

Furthermore, a distal head112of the guidewire104preferably remains free-floating relative to an extreme distal end of the catheter100but is anchored to the catheter100at a more proximal location (not shown). This anchoring helps ensure that the distal head of the guidewire104will not break off from the catheter100during use. Any suitable anchoring device may be used and is contemplated within the scope of the system.

FIG. 7illustrates a cross-sectional, longitudinal view of a longitudinal segment of one embodiment of the enhanced hypo-tube catheter system300, wherein the base hypotube catheter310comprises a substantially spiral cut body. Similar to many other embodiments disclosed herein, the hypotube catheter system300further comprises an outer polymer layer320, which may be a dip-coated polymer layer, wherein the outer polymer layer320comprises a solution that encapsulates the outside hypotube catheter surface.

The hypotube catheter system300further comprises a first inner polymer layer330which comprises a solution that encapsulates the inner hypotube catheter surface. The hypotube catheter system300further comprises an interstices polymer layer340wherein interstices polymer layer340comprises a solution that encapsulates the surfaces of the set, or plurality, of interstices313of the spiral cut hypotube body300.

The hypotube catheter system300further comprises a second inner polymer layer350, wherein the polymer layer may comprise a composition of polytetraflouroethylene (PTFE) or other Teflon™ derivative.

In conclusion, herein is presented a hypotube construction, preferably for use in forming a catheter. The system is illustrated by example in the drawing figures, and throughout the written description. It should be understood that numerous variations are possible, while adhering to the inventive concept. Such variations are contemplated as being a part of the present system.