Patent ID: 12208004

DETAILED DESCRIPTION

The following description of certain examples of the inventive concepts should not be used to limit the scope of the claims. Other examples, features, aspects, embodiments, and advantages will become apparent to those skilled in the art from the following description. As will be realized, the device and/or methods are capable of other different and obvious aspects, all without departing from the spirit of the inventive concepts. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.

For purposes of this description, certain aspects, advantages, and novel features of the embodiments of this disclosure are described herein. The described methods, systems, and apparatus should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed embodiments, alone and in various combinations and sub-combinations with one another. For example, the ridges, protrusions and/or nosecones with enlarged diameters described below could be combined in a single delivery system. The disclosed methods, systems, and apparatus are not limited to any specific aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more specific advantages be present or problems be solved.

Features, integers, characteristics, compounds, chemical moieties, or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), and/or all of the steps of any method or process so disclosed, can be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

It should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.

The terms “proximal” and “distal” as used herein refer to regions of the balloon, balloon catheter, or delivery catheter. “Proximal” means that region closest to handle of the device, while “distal” means that region farthest away from the handle of the device.

Disclosed herein is a delivery system for delivering a stent-mounted heart valve through an introducer sheath. The delivery system includes an elongate catheter supporting a capsule. The capsule contains the stent-mounted heart valve in the crimped condition. The delivery system also includes a nosecone with a tapered distal end and a proximal end. Surprisingly, the proximal end of the nosecone, despite having a larger profile than the capsule, reduces an average peak push force for advancing the delivery system through an introducer sheath.

Disclosed herein are tips and capsules for implant delivery catheters that are particularly suitable for delivery of implants in the form of implantable heart valves, such as self-expanding implantable heart valves, through expandable delivery sheaths. Self-expanding implantable heart valves are well-known and will not be described in detail here. An example of such an implantable heart valve is described in U.S. Pat. No. 8,652,202, which is incorporated herein by reference. Expandable delivery sheaths have elastic or sectioned portions that facilitate temporary profile expansion from the forces of the passing capsule and implant.

The capsules disclosed herein may also be used to deliver other types of implantable devices, such as self-expanding (or balloon expandable) implantable heart valves, stents or filters. The terms “implant” and “implantable” as used herein are broadly defined to mean anything—prosthetic or not—that is delivered to a site within a body. A diagnostic device, for example, may be an implantable. The term “implant” as used herein also does not need to be a permanent implant—for example devices used to deliver permanent implants are also implants temporarily. An implant could be any device delivered into the body for a procedure.

FIG.1illustrates a delivery catheter assembly1of one embodiment of the present invention including an elongate, expandable delivery sheath3with a lumen to guide passage of an implant delivery catheter supporting a prosthetic implant5, such as a prosthetic heart valve. At a proximal end the sheath3includes a hemostasis valve that prevents leakage of pressurized blood. The delivery catheter assembly1can include a steerable guide catheter7(also referred to as a flex catheter). The delivery catheter assembly1can also include a capsule13which can have an enlarged diameter to hold the prosthetic implant5. The capsule13can, for example, restrain a self-expanding implant to prevent premature expansion prior to reaching the procedure site. The delivery catheter assembly1also includes a contoured tip or nosecone11that can be joined with the capsule13to contain the prosthetic implant5.

Generally, during use in one embodiment, the sheath3is passed through the skin of patient (usually over a guidewire) such that the distal end region of the sheath3is inserted into a vessel, such as a femoral artery, and then advanced to a procedure site—such as over the aortic arch to a native aortic heart valve. The nosecone11and capsule13are inserted through the hemostasis valve at the proximal end of the expandable sheath3. The sheath3can be made at least partially of an elastic material and be expandable in the radial direction. Radial expansion facilitates the passage of the capsule13and nosecone11. The steerable guide catheter7can be used to advance the nosecone11and capsule13through to and out of the end of the sheath3. The nosecone11is separated from the distal end of the capsule13, such as by advancement of an inner catheter14supporting the nosecone, as illustrated inFIG.5A. The prosthetic implant5is advanced out of the capsule13along with the nosecone11and, in the embodiment having a self-expanding stent, expands in the native heart valve or other procedure site as it emerges from the capsule. The process could also reveal a balloon-expandable stent for subsequent balloon expansion.

As shown schematically inFIG.2, in one embodiment, a distal end of the guide catheter7supports the capsule13and the nosecone11is mounted on the capsule13. The external surfaces of the nosecone11and capsule13abut the adjacent, expanded wall surfaces of the delivery sheath3.

The capsule13, in one embodiment, has a cylindrical sleeve structure that defines a lumen configured to hold the prosthetic implant5in a crimped condition. The capsule13shown inFIG.2has a proximal end29and a distal end31. The proximal end29of the capsule13can be coupled to the distal end of the guide catheter7. In some embodiments, the proximal end29of the capsule13is an integral extension of a tubular sheath surrounding the outside of the distal end of the guide catheter7. In other embodiments, the proximal end29of capsule13can be attached to the guide catheter7, for example, by heat shrinking.

The distal end31of the capsule13has an opening extending distally that communicates with the lumen defined within the capsule. The lumen can be sized to hold the prosthetic implant5in its crimped, low profile state. The capsule13can be configured to also exert compression stress onto the prosthetic implant5to hold it in a crimped state. For example, the tubular wall structure of the capsule13can surround and have inner wall surfaces exerting restraining contact against outer surfaces of a self-expanding, nitinol frame stent of a prosthetic heart valve. The distal end31of the capsule13in the illustrated embodiment has a circular free edge (not shown) that can be mated with a correspondingly sized and shaped opening (not shown) in the proximal-facing surface of the nosecone. Additional details of an exemplary delivery capsule can be found in commonly assigned U.S. Patent Publication No. 2014/0343670, which is hereby incorporated herein by reference.

As shown inFIG.2, in one embodiment, the nosecone11includes a tapered distal end15and a proximal end17. The distal end15of the nosecone11includes a distal facing surface19and a contoured surface21. The distal facing surface19can be a flat, circular surface that has a smaller profile or diameter than the remainder of the body of the nosecone11. The distal facing surface19also has about the same, or smaller, diameter than the adjacent guide catheter7. Generally, the distal end facing surface19is sized to fit within the unexpanded diameter of the sheath3and has an atraumatic (such as flat) shape for safety reasons. Other atraumatic shapes can be rounded or hemispherical shapes. Also, other non-circular shapes can be used for the distal facing surface19.

The contoured surface21of the nosecone11is, in one embodiment, axisymmetric and starts with the small diameter of the distal facing surface19and expands in diameter moving proximally (towards the cardiologist holding the handle) until reaching the proximal end17. The contoured surface21can be broken down into a progressive expansion portion23, a rounded portion25and an inflection point27. The progressive expansion potion23expands smoothly at a rate increasing with proximal progression before splining into the rounded portion25. The rounded portion25is more bulbous with a slowed expansion of diameter in the proximal direction until the inflection point27, at which point the diameter begins to decrease moving proximally. Restated, the inflection point27defines the largest diameter (or nosecone diameter) where the expansion in diameter of the contoured surface21stops and then the proximal end17begins with a shrinking diameter. Thus, at the inflection point27the proximal-most boundary of the distal end15(and of the contoured surface21) and the distal-most boundary of the proximal end17share the same largest diameter.

As shown inFIG.2, the distal end31of the capsule13has a smaller diameter than the maximum diameter of the proximal end17of the nosecone11, thus the nosecone is oversized relative to the capsule. Surprisingly, the inventors have determined that this oversizing actually reduces the forces needed to advance the capsule13through the sheath3to its deployment location. Without being wed to theory, the inventors believe that the oversized diameter of the nosecone11pushes the expandable sheath3wall away from the capsule13at an angle. Pushing the expandable sheath away from the capsule reduces the contact area between the two and thus reduces the friction of the sheath3(which includes an elastic component compressing it inwards) against the advancing capsule13. Also, the oversized nosecone11can act as a dilator making the rest of the sheath3more compliant for the remainder of the delivery catheter assembly1.

Notably, the term “diameter” as used herein is not limited to circular cross-sections. Instead, diameter refers to a width through a centroid of the cross-section of the shape, such as a cross-section of the nosecone11taken perpendicular to the long-axis of the catheter assembly1. Although circular cross-sections are shown for the nosecone11and/or the capsule13, they can have other shapes, such as ovals, rounded rectangles and other shapes, including irregular shapes. The maximum diameter of such cross-section is simply the largest diameter seen by the expandable delivery sheath3as the nosecone11and capsule13are advanced therethrough. Generally, then the concept of enlarged profiles for the nosecone11(and the capsule13) are realized when some diameter is larger than the base capsule13itself needed to hold and deliver the implant5. Thus, the elliptical cross-section can have a major axis that exceeds the capsule13and a minor axis that matches the capsule13and still serves to open up the sheath3and reduce advancement forces for the trailing capsule13.

In some embodiments, the capsule13can be made of or coated by polyether ether ketone (PEEK). PEEK is advantageously a lubricious polymer, but other lubricious materials could also be used for—or coated on—the surfaces of the nosecone11.

Push forces were calculated for various nosecone designs. The sheath3used in testing was an expandable E-SHEATH from Edwards Lifesciences, Inc. (U.S. Pat. No. 8,790,387, which is hereby incorporated by reference in its entirety). The sheath3was extended through a model of an aorta in a water bath at a temperature of 37 degrees C. A 0.035″ extra-stiff guidewire was inserted through the entire length of the aortic model. The sheath3with the introducer was inserted into the aortic model over the guidewire. The water level was verified to be up to the hub of the sheath3. The hub of the sheath3was secured to a force gauge plate using a zip tie.

The proximal end of the guidewire was inserted through the catheter nosecone and pushed through the catheter until being exposed from the back end of the catheter. The nosecone tip15was then advanced over the guidewire until positioned at the proximal side of the first seal in the introducer housing. The force gauge was zeroed and a timer started. Then, the guidewire was pinned and the nosecone further advanced over the guidewire and through the seal of the sheath3. The nosecone and capsule11,13continued to be advanced through the remainder of the sheath3until exiting the tip of the sheath. The insertion time from start to finish was within 20-30 seconds. The forces, including peak push force, and insertion time were measured. Push forces were determined at each 2 cm of advancement through the delivery sheath3.

Table 1 below shows the results of the peak push force testing when the nosecone11was oversized by various amounts. Typically, an increase in the diameter of the delivery capsule13yields higher peak push forces due to increased frictional forces between the capsule13and the sheath3. However, providing a nosecone11with a greater diameter than the capsule13diminished the peak push forces, in some cases down to the mid 20 N range. The capsule delivery cylinder outside diameter is shown in the first column and the oversizing of the nosecone11in thousands of an inch is shown in the second column. The values in the oversizing column represent the difference between the widest diameter of the nosecone11and the outer diameter of the capsule delivery cylinder. The “N” column shows the number of tests. The term UTL designates the statistical upper tolerance limit of the data acquired from the peak push force testing.

TABLE 1Push Force Summary Through 14 Fr E-Sheath-PEEKDelivery Cylinder (Capsule)NoseAvgUTL ofDeliveryConePeakPeakNosecone/CylinderOverPushPushcapsuleODSizingForceForcediameter(in)(in)N(N)(N)ratio0.2530.010220.5*1.0400.2530.001232.5*1.0040.2510.001229.5*1.0040.2690.0061526.432.61.0220.2440.0011525.332.61.004

Generally, the desired upper tolerance limit for peak force is about 45 N. To meet this criteria, an average peak force of 25-30 N is targeted. Experimentation showed that the nosecone diameter being at least 1.002 times the capsule diameter, for example, from 1.002 to 1.045 times the capsule diameter, gave a peak push force upper tolerance limit of less than 40 N, and in particular less than 33 N. Notably the higher forces were present in the smaller diameter oversizing.

The sheath3used to attain the testing values shown in Table 1 had a standard 14 French diameter. However, the size of the nosecone11and capsule13can be adapted to other sheath sizes to attain similar values for peak push forces. For example, other verification tests were run using 16 French sheaths and CENTERA Model 9550C catheters with sizes of 23 mm, 26 mm and 29 mm. The average peak push force and the upper tolerance limit of the push force were under the 40 N threshold during these other verification tests.

Beyond push force reduction, the oversized nosecone11has the advantage of being easy to manufacture (by molding). Also, the oversized nosecone11works well with a capsule13—especially a capsule having its distal end31with a thinned out wall. The thinned out wall promotes flaring for easier withdrawal and recapture of the prosthetic implant5within the capsule13. And, the oversized nosecone11, because of its larger diameter, can still mate with the flared-out distal end31of the capsule13.

FIG.3shows an example capsule13of another embodiment including one or more bumps or other protrusions33positioned on the distal end31of the capsule. For example, the protrusion33can be an annular protrusion extending circumferentially around (in a ring) the entirety of the distal end31of the capsule13. Like the nosecone11, the protrusion33can have a smooth, continuous shape. The protrusion33's configuration urges the sheath3away from the exterior of the capsule13. The protrusions33thus can also reduce the average peak push force resulting from advancement of the capsule13through the sheath3.

The protrusions33can also include one or more rounded bumps, e.g., hemispherical-shaped protrusions, arranged in a spaced array around the distal end31of the capsule13. The protrusions33could also be combined with an oversized nosecone11.

FIGS.4A and4Bshow another example capsule13including a plurality of ridges35extending longitudinally along the outside surface of the capsule13. The ridges35are sized and spaced so as to space the inside of the sheath3away from the capsule13as it advances along the inside of the sheath3. The ridges35are shown inFIG.4Aas having parallel edges extending longitudinally in the direction of the axis of the delivery catheter assembly1and as having rectangular cross-sectional shapes inFIG.4B. The ridges35extend around the capsule in a spaced arrangement and are preferably 6 to 16 in number.

As illustrated inFIG.4B, the capsule13can include a plurality of ridges35having the same height, the height of a ridge35measured between the outer surface of the capsule and outer surface of the ridge35. It is contemplated that the capsule13can include a plurality of ridges35having different heights. As shown inFIG.4B, an outer diameter of the capsule13defined the ridges35can be determined by the distance between the outer surfaces of two opposing ridges35. The outer diameter can also be determined by taking an average height of the ridges and adding it to the diameter of the capsule13.

Other cross-sectional shapes for ridges35can also be employed, such as rounded, square, irregular or semi-circular shapes. Advantageously, by adding ridges35along the length of the capsule13—which defines the largest diameter of the delivery catheter assembly1—the frictional force between the capsule13and the inside surface of the sheath3may be reduced. This is believed to be a result of changing the contact area between the capsule13and the inside diameter of the sheath3. It is also contemplated that the spacing between the ridges35could vary to reduce contact area between the capsule13and the sheath3.

FIGS.5A-Dshow a method of encasing a prosthetic implant5such as a self-expanding heart valve5in a capsule13to prepare it for delivery (or to retrieve it when needing to be repositioned within the patient). In this embodiment, the nosecone11includes a neck12positioned proximal the proximal end17. The neck has a stepped down diameter and a cylindrical shape. In the embodiment ofFIG.5A, the self-expanding heart valve5can be partially encased in the capsule13with its proximal end coupled to the delivery system, such as the nosecone catheter. The capsule13is then slid distally over the remainder of the self-expanding heart valve5so that less of it is visible, as illustrated inFIG.5B. As shown inFIG.5C, the capsule13continues sliding distally until only the distal end of the self-expanding heart valve5is visible, and it is in close proximity with proximal end17of the nosecone11. Also, at this stage, the distal stent structure of the implant5overlaps onto and can be supported by the neck12.FIG.5Dillustrates the capsule13slid completely over the self-expanding heart valve5such that the distal end of the self-expanding heart valve5can be sandwiched between the neck12of the nosecone11and the distal end31of the capsule13. Also, in this position the distal end of the capsule13abuts the proximal end17of the nosecone11where its diameter steps up from the neck12.

During a procedure, the process ofFIGS.5A-Dcan be reversed and continued for complete withdrawal of the capsule13from coverage of the implant5. Then the stent mounted heart valve5can be released (if it is self-expanding and anchored, for example) or expanded via balloon or other device. Also, if the implant is needing to be retrieved for repositioning or removal, the procedure ofFIGS.5A-Dcan be repeated to retract the implant back into the capsule13.

In view of the many possible embodiments to which the principles of the disclosed catheter assembly can be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting in scope. Rather, the scope of the disclosure is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims.