Rapid exchange pre-dilator

A predilation device may comprise a shaft portion and a distal tip having helical threadings. The predilation device may further include a rapid exchange element rotatably coupled to the shaft portion. A guidewire may slidably engage the rapid exchange element and may guide the predilation device to a lesion site. The predilation device may be positioned with the distal tip abutting the lesion. The shaft portion may be rotated, thereby rotating the tip and causing the tip to pass through the lesion and predilate the lesion. In some embodiments, the tip may remove lesion material.

BACKGROUND OF THE INVENTION

Angioplasty catheters, stents and stent delivery systems are generally known in the art. Both over-the-wire and rapid-exchange type catheters are known. An inflation balloon may be delivered to a deployment site, such as a lesion or occlusion, in a reduced or unexpanded configuration. Once properly positioned within a lesion, the balloon may be expanded, thereby dilating the lesion. In some cases, a stent may be delivered to the site of a lesion where it may be used, sometimes in conjunction with an inflation balloon, to dilate the lesion and/or to support a vessel at the site of a dilated lesion.

When vessels are significantly occluded, it may be difficult to position an inflation balloon or unexpanded stent across the lesion. It may even be difficult to cross the lesion with a guidewire. The options generally available for treating a significantly or completely occluded vessel include using a rotational atherectomy device to debulk hard and/or calcified lesion material, or invasive bypass surgery.

There remains a need for a device capable of predilating a lesion. A predilation may allow for an inflation balloon and/or stent delivery system to traverse the lesion, thereby providing an alternative to rotational atherectomy devices or invasive bypass surgery.

Desirably, a predilation device may be capable of rapid-exchange type operation.

Further, there remains a need for a device capable of allowing an over-the-wire type catheter to be used in a rapid-exchange type method.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, a predilation device may comprise a catheter shaft having a distal tip, the distal tip having helical threadings, and a rapid exchange element having a first internal passageway and a second internal passageway. A portion of the catheter shaft may pass through the first internal passageway, and the rapid exchange element may be rotatably coupled to the shaft. The rapid exchange element may further be fixed against moving along the axis of the shaft.

A predilation device may further comprise a guidewire adjacent to the catheter shaft, and a portion of the guidewire may pass through the second internal passageway of the rapid exchange element.

In some embodiments, a predilation device may further comprise a stent oriented about the shaft between the tip and the rapid exchange element. In some embodiments, a predilation device may further comprise an inflation balloon oriented about the shaft between the tip and the rapid exchange element. In some embodiments a stent may be oriented about an inflation balloon. An outer diameter of the tip may be equal to or greater than an outer diameter of the stent and/or balloon when the stent/balloon is unexpanded.

In another embodiment, a predilation device may comprise a shaft having a distal tip and an inner lumen, the inner lumen extending through the tip. The distal tip may be made of metal and may have helical threadings.

In some embodiments, a method of predilating a lesion may comprise positioning a guidewire within a vessel such that a distal end of the guidewire reaches a lesion. A predilation device as described herein may be guided to the lesion using the guidewire. The predilation device may be positioned with the tip abutting the lesion. The catheter shaft may be rotated and advanced thereby causing the tip to remove lesion material and predilate the lesion. The predilation device may be removed and a stent may be placed across the predilated lesion.

In some embodiments, the invention is also directed to a rapid exchange clip having a catheter lumen extending therethrough and a guidewire lumen extending therethrough. The rapid exchange clip may be clipped onto a catheter shaft and may engage the catheter shaft. In some embodiments, the rapid exchange clip may frictionally engage a catheter. The use of a rapid exchange clip may allow a non-rapid exchange type catheter to function or be used as a rapid exchange catheter.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows an embodiment of a predilation device10which may be used to predilate a lesion, occlusion, or other obstruction within a vessel. The predilation device10may generally comprise a shaft portion30and a distal tip20. In some embodiments, the shaft portion30may have a substantially constant diameter along its length. The shaft portion30may extend proximally and may be of any suitable length to extend outside of a patient's body. Desirably, the proximal end of the shaft portion30may be rotated, which may cause rotation of the entire shaft portion30and tip20. The shaft portion30may be made of any suitable material, such as catheter materials including, but not limited to, moldable polymers, polyether block amide (PEBA), nylon or polyethyleneterephthalate (PET), polyurethane, latex, silicone rubber, natural rubber, polyvinyl chloride, polyamide, polyamide elastomer, copolymer of ethylene and vinyl acetate, polyethylene, polyimide, stainless steel and suitable alloy materials such as nickel-titanium alloys, cobalt-chromium-nickel alloys, etc.

The distal tip20is desirably coupled to and arranged to rotate with the shaft portion30. The tip20desirably includes a tapered portion22which may taper to a point24, or in some embodiments may taper to a blunted or rounded point. The tip20desirably includes a shaped surface which allows for grinding, screwing or burrowing into a lesion or occlusion. For example, the tip20may include threadings26which may spiral in helical fashion from the distal point24to a proximal end28of the tip20. Desirably the threadings26may be arranged to allow the predilation device10to burrow into an occlusion as the shaft portion30is rotated, for example in a clockwise direction.

The tip20may be made from any suitable materials, such as polymers, ceramics and metals including implant grade stainless steel such as 316LS. A tip may be formed using any suitable method including molding, casting, machining, grinding, laser ablation, etc. In some embodiments the tip20may comprise the same material as the shaft30. In some embodiments, the shaft30may be molded, extruded and machined or otherwise manufactured with an integral tip20. In some embodiments, the tip20may comprise a separate piece and may be attached to the shaft30using any suitable method, such as crimping, swaging, gluing, welding, fusing, etc., as well as any type of mechanical cooperation between the tip20and the shaft30, such as screw threadings, click-fit connections, press-fit connections, etc.

In some embodiments, the largest outer diameter of the threadings26may be greater than the outer diameter of the shaft30.

The predilation device10may further comprise a rapid exchange clip50which may be rotatably attached to the shaft portion30and may provide for sliding engagement with a guidewire12.

FIGS. 2 and 3show an embodiment of a rapid exchange clip50in greater detail. A rapid exchange clip50may include a body portion52having a first passageway54and a second passageway56extending therethrough. The first passageway54may be larger than the second passageway56, for example having a larger diameter. The first passageway54may run parallel to the second passageway56. A rapid exchange clip50may be made from any suitable material such as metals, ceramics, moldable polymers, etc.

A rapid exchange clip50may include a first body portion52aand a second body portion52b, which may be connected together. For example, the two body portions52a,52bmay be connected via a hinge connection53. The two body portions52a,52bmay further include a suitable engagement mechanism (not shown) to hold the rapid exchange clip50closed when it is positioned about the shaft portion30of the predilation device10. For example, one body portion52amay include protruding pins that are constructed and arranged to engage complimentary apertures or holes in the other body portion52b. In other embodiments, the body portions52a,52bcould include snap tabs, complimentary ties, a hook and latch, or any other suitable engagement mechanism.

When a rapid exchange clip50is properly positioned and installed with respect to the shaft30, the shaft30may extend through the first passageway54. Desirably, the shaft30is free to rotate within the first passageway54. In some embodiments, the rapid exchange clip50may engage the shaft30such that, although the shaft30remains free to rotate, the rapid exchange clip50is fixed against moving axially along the length of the shaft30.

A guidewire12may be positioned within the second passageway56. Desirably the second passageway56and guidewire12are dimensioned such that the guidewire12may move freely with respect to the rapid exchange clip50, and the rapid exchange clip50may slide along the guidewire12. Thus, a guidewire12may be used to guide the predilation device10to a lesion site.

A rapid exchange clip50may be provided as an integral portion of the predilation device or as a separate unit as depicted inFIGS. 2 and 3. When the rapid exchange clip50is a separate unit, the shaft30may be positioned next to a guidewire12and the rapid exchange clip50may be closed around the shaft30and the guidewire12.

In some embodiments, rapid exchange clip50may be used to convert an over-the-wire type catheter or any non-rapid-exchange type catheter into a rapid-exchange type catheter. A rapid exchange clip50may be secured about any catheter, thereby giving the catheter the capability of rapid-exchange functionality via the second passageway/guidewire lumen56of the rapid exchange clip50. In some embodiments, the rapid exchange clip50material defining the first passageway/catheter lumen54may frictionally engage a catheter. In some embodiments, the first passageway54may include an internal raised flange which may contact and engage a catheter. Any embodiment of a rapid exchange clip50described herein may be used with a prior art catheter to provide rapid exchange functionality. Thus, in some embodiments, a rapid exchange clip50may be rotationally engaged with a non-rapid-exchange type catheter shaft.

Various embodiments of a predilation device10may be provided with various amounts of shaft30length between the tip20and the rapid exchange clip50.

FIG. 4shows an embodiment of a predilation device10having an engagement mechanism46between the shaft30and the rapid exchange clip50which allows the shaft30to rotate yet remain axially fixed with respect to the rapid exchange clip50. The first passageway54of the rapid exchange clip50may include a raised flange60which may be annular in shape. The raised flange60may be made from a separate material or from the same material as the rapid exchange clip50. Desirably, the raised flange60may be formed integrally with the rapid exchange clip50, for example during molding of the rapid exchange clip50.

The raised flange60may include a proximal lateral surface62and a distal lateral surface64. The portion of the first passageway54having the raised flange60desirably has an inner diameter that is less than the inner diameter of other portions of the first passageway54. The first passageway54may also be described as having a first portion70, second portion72and third portion74, wherein the internal diameter of the second portion72is less than the internal diameter of the first portion70. The internal diameter of the second portion72may also be less than the internal diameter of the third portion74. The internal diameter of the first portion70may be approximately equal to the internal diameter of the third portion74.

The shaft30may include an annular groove32that is arranged to engage the raised flange60of the rapid exchange clip50. The groove32may include a proximal lateral wall34and a distal lateral wall36. When the rapid exchange clip50is positioned about the shaft30, desirably the raised flange60of the rapid exchange clip50sits within the groove32of the shaft30. The distal lateral wall36of the shaft30may abut the distal lateral surface64of the raised flange60and may prevent the shaft30from moving proximally with respect to the rapid exchange clip50. The proximal lateral wall34of the shaft30may abut the proximal lateral surface62of the raised flange60and prevent the shaft30from moving distally with respect to the rapid exchange clip50. Thus, the interaction between the raised flange60and the groove32allows the shaft30to rotate with respect to the rapid exchange clip50while fixing the position of the rapid exchange clip50along the length of the shaft30.

FIG. 5shows another embodiment of a predilation device10having another embodiment of an engagement mechanism46between the shaft30and the rapid exchange clip50which allows the shaft30to rotate yet remain axially fixed with respect to the rapid exchange clip50. The first passageway54of the rapid exchange clip50may include a groove58which may be annular in shape. The groove58may include a proximal lateral wall66and a distal lateral wall68. The portion of the first passageway54having the groove58desirably has an inner diameter that is greater than the inner diameter of other portions of the first passageway54. The first passageway54may also be described as having a first portion70, second portion72and third portion74, wherein the internal diameter of the second portion72is greater than the internal diameter of the first portion70. The internal diameter of the second portion72may also be greater than the internal diameter of the third portion74. The internal diameter of the first portion70may be approximately equal to the internal diameter of the third portion74.

The shaft30may include a raised flange40which may be annular in shape and may be arranged to engage the groove58of the rapid exchange clip50. The raised flange40may include a proximal lateral surface42and a distal lateral surface44. When the rapid exchange clip50is positioned about the shaft30, desirably the raised flange40of the shaft30sits within the groove58of the rapid exchange clip50. The distal lateral wall68of the groove58may abut the distal lateral surface44of the raised flange40and may prevent the shaft30from moving proximally with respect to the rapid exchange clip50. The proximal lateral wall66of the groove58may abut the proximal lateral surface42of the raised flange40and prevent the shaft30from moving distally with respect to the rapid exchange clip50. Thus, the interaction between the raised flange40and the groove58allows the shaft30to rotate with respect to the rapid exchange clip50while fixing the position of the rapid exchange clip50along the length of the shaft30.

A raised flange40may be made from the same material as the shaft30or may be made from a different material. A raised flange40may comprise a section of larger diameter formed during the manufacturing process, such as during extrusion of the shaft30. In some embodiments, a raised flange40may comprise a separate length of material which is coupled to and positioned between a distal length and proximal length of the shaft30. In some embodiments, a raised flange40may comprise a ring or collar that is positioned about the shaft30.

FIGS. 5 and 6show an embodiment of a predilation device10wherein the shaft30and tip20may include an internal cavity38or fluid passageway. The tip20may include one or more apertures76which may be in fluid communication with the internal cavity38. Plaque or other lesion material being removed by the predilation device10may be drawn through the apertures76, through the internal cavity38along the length of the shaft30and may be exhausted out the proximal end of the shaft30. In some embodiments, suction may be applied to the proximal end of the shaft30to actively draw lesion material into the internal cavity38and carry it away.

FIGS. 7 and 8show portions of further embodiments of a predilation device10. A rapid exchange clip50may further include one or more bearing grooves78, which may be annular in shape. The inner diameter of a bearing groove78is desirably larger than the inner diameter of the first passageway54immediately adjacent to the bearing groove78. A plurality of ball bearings80may be positioned within each bearing groove78. The ball bearings80may abut the inner surface of the bearing groove78and may abut a surface of the shaft30, thereby allowing the shaft30to rotate smoothly within the first passageway54of the rapid exchange clip50. In another embodiment (not shown), a bearing groove78may be located in the shaft30as opposed to the rapid exchange clip50.

FIG. 8shows an embodiment where the rapid exchange clip50may include a bearing groove78and the shaft30may include a complimentary bearing groove78a. Ball bearings80may sit partially within the bearing groove78and partially within the complimentary bearing groove78a. In embodiments having this feature, the interaction of the bearing grooves78,78aand the ball bearings80may prevent the rapid exchange clip50from displacing along the axis of the shaft30.

FIG. 9shows another embodiment of a tip20, which may include threadings26. The distal end of the tip20may further include a grinding portion25, which may include teeth27, ridges or any other suitable textured surface which may be used to grind into a lesion. In some embodiments, the teeth27or portions of a textured surface may be rigid and/or sharp. A tip20which includes a grinding portion25may be useful for grinding into partially or totally occluded or calcified lesions.

FIG. 10shows another embodiment of a predilation device10, which may include a shaft30, tip20and rapid exchange clip50as herein described. The predilation device10may further comprise an inflation balloon84and/or a stent delivery section86, which may be located between the tip20and the rapid exchange clip50. In some embodiments, a stent delivery section86may include an inflation balloon84. A stent delivery section86may further include a stent90or other expandable medical device, which may include balloon expandable stents, self-expanding stents, and the like. A balloon expandable stent may be positioned over a folded inflation balloon84in an unexpanded state. A self-expanding stent may be positioned directly over the shaft30, or in some embodiments over a folded inflation balloon84in an unexpanded state. A self-expanding stent may further be covered by a retractable sheath92which may retain the stent90in an unexpanded state.

When a predilation device10includes an inflation balloon84, the shaft30desirably includes an inflation lumen85which may be in fluid communication with an interior portion of the inflation balloon84. In some embodiments, a shaft30may comprise an inner shaft and an outer shaft. The inner shaft may be coupled to a distal end of the inflation balloon84, and the outer shaft may be coupled to the proximal end of the inflation balloon84. The area between the inner and outer shafts may comprise an inflation lumen.

An inflation balloon84and/or stent delivery section86may be initially provided in an unexpanded configuration having an unexpanded outer diameter. In some embodiments, the outer diameter of the tip20may be equal to or greater than the unexpanded outer diameter of the inflation balloon84and/or stent delivery section86. This allows the inflation balloon84and/or stent delivery section86to be positioned within a lesion that has been predilated using the predilation device10.

FIG. 11shows a sectional view of another embodiment of a predilation device10which may comprise an over-the-wire device. The predilation device10may include a tip20and shaft30, each having an inner cavity38or lumen extending therethrough. A guidewire12may extend through the inner cavity38or lumen. Thus, a predilation device10may be placed over a guidewire12and may follow the guidewire12to a lesion site.

The predilation device10may further include an inflation balloon and/or stent delivery system as discussed with respect toFIG. 10. Desirably, the outer diameter of the tip20may be equal to or greater than the outer diameter of the unexpanded inflation balloon and/or stent delivery system.

In some embodiments, a predilation device10may include a piercing jaw as disclosed in Published US Patent Application No. 2003/0208153, the entire disclosure of which is incorporated herein by reference in its entirety.

An example method of using a predilation device10will be discussed with reference toFIGS. 12 and 13.FIG. 12shows a vessel14having a lesion16. Generally, a guidewire12may be maneuvered through the body to the site of the lesion16. In some cases, the size and shape of the lesion16may block the vessel14to the extent that the guidewire12is unable to cross the lesion16. It may be desirable to predilate the lesion16in order to allow a guidewire12, angioplasty balloon or stent delivery system to be positioned within the lesion16.

A predilation device10may be delivered to the lesion16site. The rapid exchange clip50may be used to slidably engage the guidewire12, thereby allowing the predilation device10to follow the guidewire12to the lesion16site. The predilation device10may be positioned with its tip20abutting the lesion16. If a lumen17or partial lumen exists through at least a portion of the lesion16, the tip20may be positioned as far into the existing lumen17as possible.

A proximal end of the shaft30of the predilation device10may be rotated from outside the patient's body. The entire length of the shaft30may rotate, thereby causing rotation of the tip20. The rotatable engagement between the shaft30and the rapid exchange clip50desirably allows the shaft30to rotate without disturbing placement of the rapid exchange clip50or the guidewire12. As the tip20rotates, it may remove lesion16material and burrow or screw through the lesion16, thereby predilating the lesion as depicted inFIG. 13.

Once a lesion16has been predilated, the predilation device10may be retracted and removed from the vessel14. The guidewire12may be repositioned and extended through the predilated lesion16. A stent delivery system may then follow the guidewire12to the lesion16, and a stent may be placed across the predilated lesion. Thus, a predilation device10allows a significantly or totally occluded lesion to be crossed and stented.

In embodiments where a predilation device10includes an inflation balloon or stent delivery section, for example as disclosed with respect toFIGS. 10 and 11, once the lesion16has been predilated, the inflation balloon or stent delivery section may immediately be positioned within the predilated lesion.

In some embodiments, the invention is directed to a rapid exchange clip and methods of using a rapid exchange clip, for example as described in the following paragraphs.

1. A rapid exchange clip comprising:

a first body portion and a second body portion constructed and arranged to engage a catheter, the first body portion and a second body portion cooperatively defining a catheter passageway and a guidewire passageway, wherein the rapid exchange clip may be oriented about a catheter shaft, and the catheter passageway frictionally engages the catheter shaft.

2. The rapid exchange clip of paragraph 1, wherein a guidewire may be oriented adjacent to said catheter shaft; a portion of the guidewire passing through the guidewire passageway.

3. The rapid exchange clip of paragraph 1, wherein the rapid exchange clip is fixed against moving along the length of the catheter shaft.

4. The rapid exchange clip of paragraph 3, wherein the catheter passageway includes a raised flange which frictionally engages the catheter shaft.

5. The rapid exchange clip of paragraph 3, where in the catheter passageway includes a shaped wall portion constructed and arranged to rotatably engage the catheter shaft.

6. The rapid exchange clip of paragraph 1, wherein the first body portion and the second body portion are connected via a hinge.

7. The rapid exchange clip of paragraph 1, wherein the rapid exchange clip comprises a removable clip.

8. A method of using a catheter comprising:

providing a non-rapid-exchange type catheter shaft;

providing a guidewire;

providing a rapid exchange clip having a catheter passageway and a guidewire passageway;

securing the rapid exchange clip to the catheter shaft; and

orienting the guidewire within the guidewire passageway of the rapid exchange clip.

9. The method of paragraph 8, wherein the catheter passageway frictionally engages the catheter shaft.

10. The method of paragraph 8, wherein the rapid exchange clip is slidably engaged with the guidewire.

11. The method of claim8, further comprising positioning the guidewire within a patient's body and using the guidewire to guide the rapid exchange clip and catheter shaft along a length of the guidewire.

In some embodiments, the invention is directed to methods of predilating a lesion using a predilation device10, for example as described in the following numbered paragraphs.

1. A method of predilating a lesion comprising:

positioning a guidewire within a vessel, a distal end of the guidewire reaching a lesion;

providing a predilation device comprising:a catheter shaft having a distal tip, the distal tip having helical threadings; and a rapid exchange element rotatably coupled to the catheter shaft, the rapid exchange element having a passageway therethrough;

positioning a portion of the guidewire within the passageway of the rapid exchange element and guiding the predilation device to the lesion using the guidewire;

positioning the predilation device with the tip abutting the lesion;

rotating the catheter shaft while advancing the catheter shaft, thereby causing the tip to pass through the lesion.

2. The method of paragraph 1, wherein the tip predilates the lesion as it passes through the lesion.

3. The method of paragraph 1, wherein the tip removes lesion material as it passes through the lesion.

4. The method of paragraph 3, wherein predilation device further includes an internal lumen extending therethrough; the tip further comprises an aperture in fluid communication with the internal lumen; wherein material removed from the lesion is drawn through the aperture and through the internal lumen to a proximal portion of the catheter shaft.

5. The method of paragraph 1, further comprising removing the predilation device and repositioning the guidewire across the predilated lesion.

6. The method of paragraph 5, further comprising using the guidewire to guide a stent delivery system to the lesion and positioning a stent across the predilated lesion.

7. The method of paragraph 6, further comprising dilating the lesion and expanding the stent.

8. A method of predilating a lesion comprising:

positioning a guidewire within a vessel, a distal end of the guidewire reaching a lesion;

providing a predilation and stent delivery device comprising:a catheter shaft having a distal tip, the distal tip having helical threadings; a rapid exchange element rotatably coupled to the catheter shaft, the rapid exchange element having a passageway therethrough; and a stent oriented about the catheter shaft proximal to the distal tip;

positioning a portion of the guidewire within the passageway of the rapid exchange element and guiding the predilation and stent delivery device to the lesion using the guidewire;

positioning the predilation and stent delivery device with the tip abutting the lesion;

rotating the catheter shaft while advancing the catheter shaft, thereby causing the tip to pass through the lesion;

advancing the catheter shaft until the stent is positioned across the lesion; and

expanding the stent.

9. The method of paragraph 8, wherein the tip predilates the lesion as it passes through the lesion.

10. The method of paragraph 8, wherein the tip removes lesion material as it passes through the lesion.

11. A method of predilating a lesion comprising:

positioning a guidewire within a vessel, a distal end of the guidewire reaching a lesion;

providing a predilation device comprising:a catheter shaft having a distal tip and an inner lumen, the inner lumen extending through the tip, the distal tip having helical threadings;

positioning a portion of the guidewire within the inner lumen of the guidewire and guiding the predilation device to the lesion using the guidewire;

positioning the predilation device with the tip abutting the lesion;

rotating the catheter shaft while advancing the catheter shaft, thereby causing the tip to pass through the lesion.

12. The method of paragraph 11, wherein the tip predilates the lesion as it passes through the lesion.

13. The method of paragraph 11, wherein the tip removes lesion material as it passes through the lesion.

14. The method of paragraph 11, further comprising removing the predilation device and repositioning the guidewire across the predilated lesion.

15. The method of paragraph 14, further comprising using the guidewire to guide a stent delivery system to the lesion and positioning a stent across the predilated lesion.

16. The method of paragraph 15, further comprising dilating the lesion and expanding the stent.

17. The method of paragraph 11, wherein the tip further comprises an aperture in fluid communication with the internal lumen; wherein material removed from the lesion is drawn through the aperture and through the internal lumen to a proximal portion of the catheter shaft.