Devices and methods for crimping medical devices

A crimping device used with a medical device can include at least one force-applying surface configured to compress the medical device by applying a force to a surface of the medical device. The crimping device also includes at least one protruding element extending from the force-applying surface and arranged to least partially extend into one of the openings defined by frame struts while the medical device is being crimped. The extension of the at least one protruding element at least partially into one of the openings prevents at least a portion of the soft layer of the medical device from protruding between struts of the outer frame of the medical device while the device is being crimped.

FIELD

Embodiments of the present invention generally relate to medical devices. Specifically, embodiments relate to devices and methods for crimping a medical device to facilitate placement of the medical device in a subject's body.

BACKGROUND

Medical devices, for example, stents, prosthetic valves, and other implantable medical devices, can be compressed to facilitate delivery of the devices at an implantation site in a subject's body, for example, a native cardiac valve. The medical devices are delivered to the implantation site via a delivery device (for example, a catheter) having radial dimensions that are smaller than the unconstrained or expanded radial dimensions of the medical device (i.e., the radial dimensions of the medical device, when the medical device is in an unconstrained state), and/or that are smaller than the dimensions of the medical device upon deployment of the medical device at the implantation site, a native cardiac valve. To facilitate insertion of such a medical device into or on the delivery device, the medical device is compressed (typically, at least radially).

BRIEF SUMMARY

In some embodiments, a crimping device is used with a medical device. The medical device includes a frame that has struts defining openings, and includes a soft layer coupled to the frame. The crimping device includes at least one force-applying surface configured to compress the medical device by applying a force to a surface of the medical device. The crimping device also includes at least one protruding element extending from the force-applying surface and arranged to least partially extend into one of the openings defined by the struts while the medical device is being crimped. The extension of the at least one protruding element at least partially into one of the openings prevents at least a portion of the soft layer of the medical device from protruding between struts of the outer frame of the medical device while the device is being crimped.

In some embodiments, a method for crimping a medical device includes compressing the medical device by applying a force to an outer surface of the medical device with a force-applying surface. The medical device includes a frame that comprises struts defining openings, and includes a soft layer coupled to the frame. The method also includes inserting at least one protruding element that extends from the force-applying surface at least partially into one of the openings defined by the struts while the medical device is being compressed to prevent at least a portion of the soft layer of the medical device from protruding between the struts of the frame of the medical device.

In some embodiments, a crimping system can be used with a medical device. The medical device includes a frame having struts that define openings, and includes a soft layer coupled to the frame. The crimping system includes a crimping device. The crimping device includes at least one force-applying surface configured to compress the medical device by applying a force to a surface of the medical device. The crimping system also includes a support member configured to be operatively coupled to the medical device while the force-applying surface applies a force to the surface of the medical device. The support member includes at least one protruding element extending from a surface of the support member and arranged to at least partially extend into one of the openings defined by the struts while the crimping device crimps the medical device. The extension of the at least one protruding element at least partially into one of the openings prevents at least a portion of the soft layer of the medical device from protruding between struts of the outer frame of the medical device while the device is being crimped.

DETAILED DESCRIPTION

Referring toFIGS. 1-3, which are schematic illustrations of a winged crimping device20, according to an embodiment, for use with a medical device22. Medical device22can be any medical device that can be compressed to facilitate delivery of the device at an implantation site in a subject's body. For example, medical device22can be a stent, prosthetic valve, or any other implantable medical device.

In some embodiments, medical device22includes a soft layer (not shown inFIGS. 1-3), for example, a soft inner lining such as a skirt that surrounds the periphery of medical device22, and/or prosthetic valve leaflets. Medical device22can also include a frame30(shown inFIG. 2) that comprises struts32. In some embodiments, the soft layer can be a polymer, such as a polyurethane, polytetrafluoroethylene, or polydimethylsiloxane; a polyester; any other suitable biocompatible synthetic material; biological pericardial tissue; synthetic pericardial tissue; or any other suitable biological material. In some embodiments, frame30can be rigid. Frame30can be made of a metal, for example, cobalt chromium; nickel molybdenum; iron alloy; tantalum; 316L steel; a shape-memory alloy, such as nitinol; or any other suitable metal. In some embodiments, medical device22can be a prosthetic valve that includes a soft lining, soft prosthetic valve leaflets, and frame30. For example, medical device22can be a prosthetic valve as described in U.S. Patent Application Publication No. 2008/0071363 to Tuval et al. or U.S. Patent Application Publication No. 2006/0259136 to Nguyen et al.

In some embodiments, struts32can define one or more openings36. For example, struts32can form a plurality of diamond shaped openings36that uniformly define the circumferential body of frame30. In at least some of the embodiments, the diamond shaped openings36have a different size and/or shape at the inflow end and at the outflow end of frame30of medical device22. In some embodiments, a central portion between the inflow end and the outflow end of frame30has diamond shaped openings36of a third size and/or shape to form a medical device22having a narrowed central portion. The soft layer of medical device22is coupled to frame30using any suitable attachment method, for example, suturing. In some embodiments, the soft layer axially overlaps with at least portions of one or more openings36defined by struts32. In some embodiments, the soft layer is coupled to an outside surface of frame30. In some embodiments, the soft layer is coupled to an inside surface of frame30. In some embodiments, medical device22can include one or more soft layers. For example, medical device22can be a prosthetic valve comprising a soft skirt layer coupled to the inside or outside of frame30, and one or more prosthetic valve leaflets coupled to the inside or outside of frame30. Medical device22can be crimped to facilitate delivery of device22to an implantation site in a subject's body.

Crimping device20may include one or more wings26. For example, as shown inFIGS. 1-3, crimping device20may include three wings26. Crimping device20is configured to crimp (i.e., compress) medical device22by applying one or more forces to the medical device with a force-applying surface24of wings26of crimping device20. In some embodiments, crimping device20radially compresses medical device22by applying inward radial forces to medical device22with force-applying surfaces24. Crimping device20applies the radial forces to medical device22as medical device22and crimping device20are moved through a compression funnel28(shown inFIGS. 2 and 3), which causes wings26of crimping device20to constrict and apply radial forces to medical device22with force-applying surfaces24. Wings26can be configured to pivot such that crimping device20can be constricted. For example, wings26can be configured to pivot about pivot assemblies27. In some embodiments, pivot assemblies27can be a hinge as shown inFIGS. 1-3.

In some embodiments, crimping device20can also include at least one protruding element34disposed on one or more of force-applying surfaces24. For example, as shown inFIGS. 1-3, crimping device20can include a plurality of protruding elements34disposed on each force-applying surface24. Protruding elements34can be shaped to at least partially, and in some embodiments fully, extend into an opening36defined by struts32of the frame30during at least a portion of a period during which force-applying surfaces24applies radial forces to medical device22—when medical device22is operatively coupled with crimping device20. In some embodiments, one or more of openings36in which protruding elements34extend axially overlap with a soft layer (e.g., a soft lining and/or prosthetic valve material such as prosthetic valve leaflets) of medical device22. In some embodiments, protruding elements34are sized to be smaller than openings36of frame30. For example, as shown inFIG. 1-3, protruding elements34can have a circular cross-sectional shape that is sized to fit within the diamond-shaped openings36of medical device22. In some embodiments, protruding elements34can have a non-circular cross-sectional shape, for example, a diamond, oval, polygonal, or any other suitable cross-sectional shape, that is sized to fit within openings36of frame30. In some embodiments, protruding elements34are cylindrical. In some embodiments, protruding elements34have a non-cylindrical shape, for example, a conical, hemispherical, parabolic, hyperbolic, elliptical, or any other suitable non-cylindrical shape. In some embodiments, protruding elements34are rigid. Protruding elements34can be made of a plastic, a biocompatible polymer (such as polyurethane and/or polyethyleneimine), a silicone-based material, or any other suitable material.

Protruding elements34can be configured to prevent at least a portion of a soft layer (not shown inFIGS. 1-3) of medical device22(e.g., a soft inner lining and/or prosthetic valve leaflets), which axially overlaps with openings36of frame30, from protruding between struts32of outer frame30of medical device22, while the force-applying surfaces24apply forces to medical device22—while medical device22is being crimped. In some embodiments, protruding elements34can reduce damage to the soft layer of the medical device that may result from the soft layer protruding between openings36defined by struts32while the device is crimped.

In some embodiments, winged crimping device20can be used with compression funnel28as shown inFIGS. 1-3. Medical device22is placed inside crimping device20, and crimping device20and medical device22are then pulled towards an outlet37at one end of compression funnel28. Pulling crimping device20and medical device22towards outlet37of compression funnel28causes wings26of crimping device20to constrict, which applies one or more radial forces to medical device22with force-applying surfaces24. In some embodiments, wings26constrict by pivoting. As best seen inFIG. 3, while medical device22is operatively coupled with crimping device20, protruding elements34extend from force applying surfaces24and at least partially, and in some embodiments fully, into openings36defined by struts32of frame30during at least a portion of a period (for example, the initial portion of the period) when force-applying surfaces24apply the forces to medical device22. In some embodiments, the extension of protruding elements34through openings36of frame30during the portion of the period during which the force-applying surfaces24apply the forces to medical device22prevents the soft layer (not shown inFIGS. 1-3) of medical device22from protruding between struts32of frame30when medical device22becomes partially and/or fully crimped.

In some embodiments, preventing the soft layer of the medical device from protruding between struts32when medical device22becomes fully crimped can prevent damage that may be caused to the soft layer of medical device22by struts32. Preventing the soft layer of medical device22from protruding between struts32, when medical device22becomes partially and/or fully crimped, can also reduce the crimped profile of medical device22, relative to if the soft layer of the device were to protrude between struts32.

In some embodiments, a single protruding element34is disposed on each wing26of crimping device20. In some embodiments, a plurality of protruding elements34is disposed on each wing26of crimping device20. For example, in some embodiments, more than three and/or less than seven protruding elements34are disposed on each wing26. In some embodiments, crimping device20includes a protruding element34for each opening36defined by struts32of frame30.

In some embodiments, as medical device22advances through compression funnel28, protruding elements34are configured to slide out of openings36. For example, in some embodiments, protruding elements34are angled towards outlet37of compression funnel28and away from the pivot point of wings26. For example, as shown inFIG. 3, protruding elements34define an angle α between the longitudinal axis of the respective protruding element34and the respective force-applying surface24. In some embodiments, angle α is approximately 90 degrees such that the longitudinal axis of the protruding element is approximately perpendicular with the respective force-applying surface24. In some embodiments (as shown inFIG. 3), angle α is less than approximately 90 degrees—protruding elements34are angled towards outlet37of compression funnel28and away from the pivot point of wing26. In some embodiments, angle α greater than 30 degrees. When angle α is less than 90 degrees, angle α facilitates the sliding of protruding elements34out from openings36as medical device22is advanced through compression funnel28as described above.

In some embodiments, crimping device20is used with medical device22having a soft layer coupled to an inside surface of frame30.

FIGS. 4-7illustrate a crimping device40according to another embodiment.FIG. 4shows crimping device40in the absence of medical device22when crimping device40is in an open configuration.FIG. 5shows medical device22disposed inside crimping device40when crimping device40is in the open configuration.FIG. 6shows crimping device40in the absence of medical device22when crimping device40is in a closed (i.e., crimped) configuration.FIG. 7shows medical device22disposed inside crimping device40when crimping device40is in the closed configuration.

In some embodiments, medical device22can be as described above with reference toFIGS. 1-3and comprises a soft layer (not shown) and a frame (not shown) having struts defining a plurality of openings. At least a portion of the soft layer can axially overlap with the openings of the frame.

In some embodiments, crimping device40defines a plurality of force-applying surfaces42, and is configured to crimp medical device22by applying a radial force to the outer surface of medical device22with the force applying surfaces42as seen in the transition fromFIG. 5toFIG. 7. In some embodiments, crimping device40is configured such that force-applying surfaces42move radially toward a central axis to crimp medical device22.

Crimping device40can include at least one protruding element34(which is generally as described hereinabove with reference toFIGS. 1-3) that is disposed on at least one force-applying surface42of crimping device40. In some embodiments, a plurality of protruding elements34is disposed on at least some force-applying surfaces42of crimping device40. When medical device22is operatively coupled with crimping device40, protruding elements34extend from a respective inner surface42and at least partially, and in some embodiments fully, into the openings defined by the frame struts of medical device22during at least a portion of a period (for example, the initial portion of the period) during which the force-applying surfaces42apply the forces to medical device22—while medical device22is being crimped. In some embodiments, the openings through which protruding elements34extend are axially overlapped with the soft layer. In some embodiments, the extension of protruding elements34through the openings defined by struts during the portion of the period during which the force-applying surfaces42apply the forces to medical device22prevents the soft layers of the medical device from protruding between the struts of the medical device when medical device22becomes partially and/or fully crimped.

In some embodiments, crimping device40is used with medical device22having a soft layer coupled to an inside surface of frame30.

Referring toFIGS. 8 and 9, which are schematic illustrations of an elastic crimping device50, according to an embodiment, for use with medical device22. Medical device22can be constructed as described above with reference toFIGS. 1-3and comprises a soft layer29(shown inFIG. 9) and a frame30having struts32defining a plurality of openings36. At least a portion of the soft layer can axially overlap with the openings of the frame.

Crimping device50comprises an elastic material. Crimping device50is configured to be stretched around a frame30of medical device22, such that the shape of inner surface52of crimping device50conforms to the shape of the outer surface of frame30. Inner surface52of crimping device50acts as a force-applying surface and radially compresses medical device22by applying a radial force to the outer surface of medical device22.

Crimping device50can include at least one protruding element34(which is generally as described above with reference toFIGS. 1-3) disposed on inner surface52of crimping device50. In some embodiments, as shown inFIGS. 8 and 9, a plurality of protruding elements34are disposed on inner surface52of crimping device50.

In some embodiments, the conformance of inner surface52of crimping device50with the outer surface of frame30of medical device22causes protruding elements34to at least partially, and in some embodiments fully, extend into openings36defined by struts32of frame30. In some embodiments, these openings36can be axially overlapped with a soft layer of medical device22. For example,FIG. 9shows a cross-sectional view of crimping device50operatively coupled with medical device22, in an embodiment in which frame30of medical device22defines a non-circular cross-section. As shown, the shape of elastic crimping device50conforms with the local shape of frame30, and protruding elements34extend at least partially, and in some embodiments fully, into openings36defined by struts32of frame30.

In some embodiments, crimping device50is used with medical device22having a soft layer coupled to an inside surface of frame30.

Referring toFIGS. 10 and 11, which are schematic illustrations of a support member60for use with a crimping device (not shown) according to an embodiment. In some embodiments, support member60surrounds the outside of a medical device22, before placing the medical device into the crimping device that defines one or more force-applying surfaces that are configured to crimp medical device22by applying a radial force to the outer surface of medical device22. Medical device22can be constructed as described above with reference toFIGS. 1-3and comprises a soft layer29(shown inFIG. 11) and a frame30having struts32defining a plurality of openings36.

In some embodiments, support member60can be a flexible panel or sheet that can be wrapped around medical device22. In some embodiments, support member60can be an elastic tube in which medical device22can be inserted before operatively coupling the medical device22and support member60with the crimping device. In some embodiments, support member60can be a ring configured to be placed around the outside of medical device22before medical device22is placed into a crimping device.

In some embodiments, support member60comprises at least one protruding element34that extends from an inner surface62of support member60. In some embodiments, a plurality of protruding elements34extends from inner surface62. Protruding elements34can be arranged on inner surface62such that each protruding element34extends at least partially, and in some embodiments fully, into openings36defined by struts32of frame30during at least a portion of a period (for example, the initial portion of the period) during which the force-applying surface of the crimping device applies the force to medical device22—while medical device22is being crimped. In some embodiments, the extension of protruding elements34into openings36during the portion of the period during which the force-applying surface applies the force to the medical device prevents the soft layer of the medical device from protruding between struts32when medical device22becomes partially and/or fully crimped.

In some embodiments, the crimping device may be generally similar to one of the above-described crimping devices.

In some embodiments, support member60is used with medical device22having a soft layer coupled to an inside surface of frame30as shown inFIG. 11.

As shown inFIG. 10, the axial length of support member60is substantially equal to the axial length of frame30. In other embodiments, the axial length of support member60can be more or less than the axial length of frame30. For example, the axial length of member60can be less than the axial length of frame30such that support member60forms a ring having a plurality of protruding elements34.

Referring toFIG. 12, which is a schematic illustration of a compression funnel64according to an embodiment for use with a medical device (not shown). In some embodiments, the medical device used with funnel64can be constructed as described above with reference toFIGS. 1-3and comprises a soft layer and a frame having struts defining a plurality of openings.

In some embodiments, compression funnel64comprises a plurality of struts67and a plurality of cogs66rotatably coupled to struts67. Struts67can be circumferentially spaced apart with cogs66positioned between respective struts67. Each of the plurality of rotating cogs66can define a plurality of teeth68. Teeth68are configured to act as protruding members34as described above with reference toFIGS. 1-3.

In some embodiments, compression funnel64is conical. The narrow end of the funnel is at a distal end70of compression funnel64. Distal end70can define an outlet for compression funnel64. A medical device can be crimped by being pulled through the outlet at distal end70of compression funnel64thereby acting in a similar manner as the above described compression funnel28. The inner surface of compression funnel64acts as a force-applying surface that applies a radial force to the medical device that compresses medical device22. Cogs66can be arranged on struts67such that while the medical device is moved towards and through the outlet of compression funnel64, cogs66rotate to cause teeth68to at least partially, and in some embodiments fully, extend through the openings defined by the struts of frame during at least a portion of a period (for example, the initial portion of the period) during which the force-applying surface of the funnel applies a force to the medical device. In some embodiments, the extension of teeth68of cogs66through the openings during the portion of the period during which the force-applying surface applies the force to the medical device prevents the soft layer of medical device from protruding between the struts when the medical device becomes partially and/or fully crimped.

In some embodiments, compression funnel64is used with a medical device having a soft layer coupled to an inside surface of the frame.

Referring now toFIGS. 13-15, which are schematic illustrations of a support member70, according to an embodiment, for use with a crimping device. In some embodiments, support member70is configured to be disposed inside a medical device74when medical device74is placed inside a crimping device that defines one or more force-applying surfaces configured to crimp medical device74by applying a radial force to the outer surface of medical device74. For example, the crimping device may be generally similar to one of the crimping devices described above.

In some embodiments, medical device74includes a soft layer76(e.g., a soft outer lining and/or prosthetic valve leaflets) coupled to an outside surface of frame30(which can be as described above with reference toFIGS. 1-3).

In some embodiments, support member70includes at least one protruding element34(which is generally as described above with reference toFIGS. 1-3) disposed on an outer surface72of inner compressible member70. In some embodiments, as shown inFIGS. 13-15, a plurality of protruding elements34are disposed on outer surface72of the inner compressible member.

Protruding elements34can be arranged such that when medical device74is operatively coupled with support member70, protruding elements34extend at least partially, and in some embodiments fully, into openings36defined by struts32of frame30of medical device74during at least a portion of a period (for example, the initial portion of the period) during which the force-applying surface of the crimping device applies the force to medical device74. In some embodiments, the extension of protruding elements34through openings36of frame30during the portion of the period during which the force-applying surface applies the force to medical device74prevents soft outer layer76of medical device74from protruding between struts32when medical device74becomes partially and/or fully crimped.

In some embodiments, inner compressible member70comprises a balloon, a foam material, and/or a different compressible material. Although compressible member70as shown inFIGS. 13-15is hollow (e.g., a hollow balloon), member70can be substantially solid (e.g., a solid foam device). In some embodiments, the compressibility of member70is such that outer surface72of member70conforms with the local shape of the inner surface of frame30of medical device74to facilitate the extension of protruding elements34at least partially, and in some embodiments fully, into openings36defined by struts32of frame30. For example,FIG. 15shows a cross-sectional view of support member70disposed inside medical device74in an embodiment in which frame30of medical device74defines a non-circular cross-section. As shown, the shape of support member70can conform with the local shape of frame30, causing protruding elements34to at least partially, and in some embodiments fully, extend into openings36defined by struts32of frame30.