A catheter including an elongate drive shaft having a proximal end and a distal end, an ablation burr disposed at the distal end expandable between a first position and a second position, wherein in the second position has a greater transverse dimension than in the first position. The catheter of the present invention can include a mechanism for positioning the burr eccentrically within a vessel lumen. In this context, expansion means that the burr can ablate a lumen having a larger diameter than the diameter of the lumen of the guide catheter to which the device is advanced.
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The present invention generally relates to constructions for intravascular treatment devices useful for removing vascular occlusion material from a vascular occlusion or from a vascular lumen. The invention more specifically relates to “expandable” intravascular occlusion material removal devices, as well as to methods of using those devices to treat vascular diseases. In this context, “expandable” means that the burr can ablate a lumen having a larger diameter than the diameter of the lumen of the guide catheter to which the burr is advanced.
Vascular diseases, such as atherosclerosis and the like, have become quite prevalent in the modern day. These diseases may present themselves in a number of forms. Each form of vascular disease may require a different method of treatment to reduce or cure the harmful effects of the disease. Vascular diseases, for example, may take the form of deposits or growths in a patient's vasculature which may restrict, in the case of a partial occlusion, or stop, in the case of a total occlusion, blood flow to a certain portion of the patient's body. This can be particularly serious if, for example, such an occlusion occurs in a portion of the vasculature that supplies vital organs with blood or other necessary fluids.
To treat these diseases, a number of different therapies are being developed. While a number of invasive therapies are available, it is desirable to develop non-invasive therapies as well. Minimally invasive therapies may be less risky than invasive ones, and may be more welcomed by the patient because of the possibility of decreased chances of infection, reduced post-operative pain, and less post-operative rehabilitation. One type of non-invasive therapy for vascular diseases is pharmaceutical in nature. Clot-busting drugs have been employed to help break up blood clots which may be blocking a particular vascular lumen. Other drug therapies are also available. Further, minimally invasive intravascular treatments exist that are not only pharmaceutical, but also revascularize blood vessels or lumens by mechanical means. Two examples of such intravascular therapies are balloon angioplasty and atherectomy which physically revascularize a portion of a patient's vasculature.
Balloon angioplasty comprises a procedure wherein a balloon catheter is inserted intravascularly into a patient through a relatively small puncture, which may be located proximate the groin, and intravascularly navigated by a treating physician to the occluded vascular site. The balloon catheter includes a balloon or dilating member which is placed adjacent the vascular occlusion and then is inflated. Intravascular inflation of the dilating member by sufficient pressures, on the order of 5 to 12 atmospheres or so, causes the balloon to displace the occluding matter to revascularize the occluded lumen and thereby restore substantially normal blood flow through the revascularized portion of the vasculature. It is to be noted, however, that this procedure does not remove the occluding matter from the patient's vasculature, but displaces it.
While balloon angioplasty is quite successful in substantially revascularizing many vascular lumens by reforming the occluding material, other occlusions may be difficult to treat with angioplasty. Specifically, some intravascular occlusions may be composed of an irregular, loose or heavily calcified material which may extend relatively far along a vessel or may extend adjacent a side branching vessel, and thus are not prone or susceptible to angioplastic treatment. Even if angioplasty is successful, thereby revascularizing the vessel and substantially restoring normal blood flow therethrough, there is a chance that the occlusion may recur. Recurrence of an occlusion may require repeated or alternative treatments given at the same intravascular site.
Accordingly, attempts have been made to develop other alternative mechanical methods of minimally invasive, intravascular treatment in an effort to provide another way of revascularizing an occluded vessel and of restoring blood flow through the relevant vasculature. These alternative treatments may have particular utility with certain vascular occlusions, or may provide added benefits to a patient when combined with balloon angioplasty and/or drug therapies.
One such alternative mechanical treatment method involves removal, not displacement, as is the case with balloon angioplasty, of the material occluding a vascular lumen. Such treatment devices, sometimes referred to as atherectomy devices, use a variety of means, such as lasers, and rotating cutters or ablaters, for example, to remove the occluding material. The rotating cutters may be particularly useful in removing certain vascular occlusions. Since vascular occlusions may have different compositions and morphology or shape, a given removal or cutting element may not be suitable for removal of a certain occlusion.
Alternatively, if a patient has multiple occlusions in his vasculature, a given removal element may be suitable for removing only one of the occlusions. Suitability of a particular cutting element may be determined by, for example, its size or shape. Thus, a treating physician may have to use a plurality of different treatment devices to provide the patient with complete treatment. This type of procedure can be quite expensive because multiple pieces of equipment may need to be used (such intravascular devices are not reusable because they are inserted directly into the blood stream), and may be tedious to perform because multiple pieces of equipment must be navigated through an often-tortuous vascular path to the treatment site.SUMMARY OF THE INVENTION
The present invention pertains generally to devices for performing atherectomy. In particular, various embodiments of an atherectomy device are disclosed which can ablate a lumen having a larger diameter than the diameter of the lumen of the guide catheter through which the device is advanced.
In one embodiment, an elongate shaft is provided having a proximal and a distal end. The shaft defines a lumen. A burr deflector is disposed at the distal end of the shaft. The burr deflector includes a burr engaging surface. An elongate rotatable drive shaft extends through the lumen of the first shaft. The drive shaft has a proximal end and a distal end. A burr is disposed at the distal end of the drive shaft. The drive shaft and burr are shiftable relative to the burr deflector. The drive shaft and burr may be shifted between a first position and a second position, wherein the burr is transversely shifted relative to the burr deflector. Preferably, the deflection is co-linear to the length of the drive shaft.
The burr engaging surface is preferably disposed at an acute angle to the length of the first shaft. The burr preferably includes an engaging surface disposed at an acute angle relative to the drive shaft such that the engaging surfaces provide a path along which the burr can shift transversely relative to the burr deflector.
In yet another embodiment of a device in accordance with the present invention an elongate shaft is provided which has a proximal and a distal end. The shaft defines a lumen. An elongate rotatable drive shaft extends through the lumen. The drive shaft has a proximal end and a distal end. A burr is disposed at the distal end of the drive shaft. A bushing is disposed around the drive shaft proximate the burr. A steering line is connected to the bushing. The steering line can be pulled by an operator to shift the bushing and thus the burr and drive transversely.
In yet another embodiment of a device in accordance with the present invention, an elongate rotatable drive shaft is provided having a proximal and a distal end. An ablation burr is disposed at the distal end of the drive shaft. The ablation burr includes a mechanism which expands transversely in response to the centrifugal force generated when the burr rotates.
In one embodiment, the mechanism is generally tubular and has a proximal end and a distal end constrained against expansion. The central portion of the tubular member is allowed to expand under the influence of the centrifugal force. In yet another embodiment of the mechanism, a member having a generally helical cross-section is provided which tends to unwind, increasing its transverse diameter as the burr rotates. In yet another embodiment of the mechanism, a line is provided having a proximal end and a distal end. The ends of the line are held a distance apart less than the length of the line. An abrasive is disposed on the line. As the burr is rotated, the line moves transversely. In yet another embodiment of the mechanism includes a plurality of bristles which can shift transversely under the influence of centrifugal force.
In another embodiment of the atherectomy device in accordance with the present invention, an elongate rotatable drive shaft is provided having a proximal end and a distal end. A lumen is defined through the elongate drive shaft. A balloon including an outer surface and defining a balloon enclosure in fluid communication with the inflation lumen is disposed at the distal end of the drive shaft. An abrasive is disposed on the outer surface of the balloon. The balloon can be dilated by pressure or centrifugal force to increase the transverse dimension of the abrasive surface.
In yet another embodiment of an atherectomy device in accordance with the present invention, an elongate shaft is provided having a proximal end and a distal end. The shaft defines a drive shaft lumen and an inflation lumen. A rotatable drive shaft, having a proximal end and a distal end, is disposed in the drive shaft lumen. An ablating burr is disposed at the distal end of the drive shaft. A balloon is disposed eccentrically on the drive shaft proximate the burr. The balloon can be inflated to push against the vessel wall and shift the drive shaft and burr transversely within the vessel lumen.
In yet another embodiment of an atherectomy device in accordance with the present invention, an elongate rotatable drive shaft is provided having a proximal end and a distal end. An ablation burr is eccentrically connected to the drive shaft at the distal end of the shaft. A counterweight is disposed on the burr to place the center of mass of the burr in line with the longitudinal axis of the drive shaft. The presence of the counterweight dampens whipping of the burr which might otherwise occur during rotation of the drive shaft. This embodiment is related to that disclosed in U.S. patent application Ser. No. 08/987,969, filed Dec. 10, 1997 and entitled ASYMMETRIC BURRS FOR ROTATIONAL ABLATION incorporated herein by reference.
In yet another embodiment of the atherectomy device in accordance with the present invention, an elongate shaft is provided having a proximal end and a distal end. The shaft defines a lumen therethrough. A rotatable drive shaft having a proximal end and a distal end, is disposed through the lumen. A burr, including a plurality of spring members is disposed at the distal end of the drive. The drive shaft and the burr are shiftable between a first position and a second position. In the first position, the spring members are disposed at least in part within the lumen of the first shaft and are transversely constrained thereby. In the second position, the spring members are transversely restrained less than in the first position such that the burr has a greater transverse dimension in the second position than in the first position.
In yet another embodiment of an atherectomy device in accordance with the present invention, an elongate rotatable drive shaft is provided having a proximal end and a distal end, the drive shaft includes a generally helical-shaped portion proximate the distal end biased to expand when unconstrained. An abrasive is disposed on the helical portion. The helical portion can be advanced to the site where atherectomy will be performed in a constrained and collapsed state through a guide catheter. When the helical shaped portion exits the guide catheter, the helically shaped portion, then unconstrained, will expand transversely.BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings, wherein like reference numerals refer to like reference elements throughout the several views, FIGS. 1 is a side view of catheter 10 in accordance with the present invention. As shown in
As will be appreciated by those skilled in the art, suitable manifold and motor can be provided at the proximal end of catheter 10 to rotate burr 26 and facilitate the uses of catheter 10 as herein described. Those skilled in the art will appreciate the various biocompatible materials available to construct catheter 10 including burr 26. This is also true with respect to the various embodiments of the catheters discussed below. Those skilled in the art will recognize the various manifold, motor, infusion displays control mechanisms and other devices that can advantageously be connected to the proximal ends of the catheter to facilitate their use. Additionally, those skilled in the art will recognize various biocompatible materials, and methods available to construct each embodiment.
In use, catheter 10 is advanced percutaneously to a coronary lesion including plaque 14. Burr 26 is advanced to plaque as shown by the arrow parallel to shaft 16. Burr 26 is then rotated by drive shaft 26 as shown by the arrows such that plaque deposit 14 is grounded to micro fine particles. Catheter 10 can be advanced to the lesion through a guide catheter (not shown) having an inner lumen at least slightly greater in diameter than the diameter of burr 26.
As shown in
Catheter 50 can be used as described above with respect to catheter 10. Unlike catheter 10, however, rather than having a burr deflector 22 to transversely move burr 26, burr 60 can be shifted from side to side by pulling proximally a steering wire 72 or 74. Pulling steering wire 74 proximally as steering wire 72 is allowed to move distally will shift burr 66 transversely toward wire 74 as shown by the arrow on burr 66. Similarly, burr 66 can be shifted transversely in the opposite direction by pulling steering wire 72 proximally while allowing wires 74 to shift distally.
To perform an atherectomy procedure using catheter 50, catheter 50 can be advanced to percutaneously to the cite of the lesion through a guide catheter having an inside diameter at least slightly greater than the transverse diameter of burr 66. Burr 66 can be rotated as shown by the arrow proximate drive shaft 60 and be engaged with the lesion. Burr 66 can be moved transversely by steering wires 72 and 74 as necessary to remove the plaque.
In use, catheter 110 is advanced to a lesion as described above with respect to the other catheter embodiments. Rather than including a mechanism for transversely shifting a burr however, the tubular member 130 of burr 126 is sufficiently elastic to stretch transversely under the influence of centrifugal force when tip 126 is rotated by shaft 120. Rotation of tip 126, thus will move tubular member 130 from a first position A to a second position B. In second position B, burr 126 can ablate a larger diameter path. While member 130 is moving from position A to position B, fluid may be introduced through lumens 121 and 132 as shown by the arrows into the space created inside member 130.
In use, balloon 166 is advanced percutaneously to a lesion. At the lesion, balloon 166 is inflated to increase its diameter. Abrasive surface 168 is then advanced into engagement with the plaque. Balloon 166 is then rotated to abrade plaque.
Catheter 250 is advanced as described above with respect to the alternate embodiments in accordance with the present invention to perform the atherectomy procedure. Likewise, burr 266 is rotated to abrade plaque. In order to shift burr 266 transversely within lumen 252, balloons 263 may be alternately inflated or deflated to engage the wall of vessel 252 forcing burr 266 transversely in a direction opposite the resultant force of balloons 263 incident the wall of vessel 252.
An elastomeric shell is disposed within burr 726 to avoid an increase in hemolysis or platelet aggregation. Shell 742 preferably encloses a main body 743 and unidirectional ratchet 744 including reverse positive stop 746. A threaded member 800 is threaded into a sleeve 745. Threaded member 800 is fixably connected at its distal end to stop 746 and fixably connected at its proximal end to forward motion positive stop 747. Threaded member 800 is also fixably connected to drive shaft 720. Spring members 740 are connected at their proximal ends to sleeve 745 and fixably held in position by collar 748. The distal ends of spring members 740 are fixably connected to the distal end of main body 743. Main body 743 is connected at its proximal end about a pin 804 to ratchet 744. Ratchet 744 includes teeth 802 and the main body portion includes teeth 806. Teeth 802 and 806 are shown in
In use, ratchet 744 and main body 743 can be used to control the transverse diameter D of burr 726. For example, a burr advancable through an 8F guide catheter could be expanded between 2.0 mm and 3.5 mm in diameter, at 0.25 mm intervals or steps. The ability to control the diameter of burrs 726 at such steps can be considered indexing. To increase the diameter of burr 726 by indexing, drive shaft 720 can be rotated such that teeth 802 and 806 engage each other along surfaces 808. Since surfaces 808 are inclined, teeth 806 will tend to rise out from between 802 momentarily increasing the length of burr 726. As drive shaft 720 continues to rotate, the teeth will index and reengage the adjacent teeth. As ratchet 744 was rotated, stop 746 will have moved toward stay 745 shortening the distance between distal end 749 of burr 726 and sleeve 745, thus increasing the diameter of burr 726. This assumes that the spring members 740 bias burr 726 toward its largest diameter. This procedure can be repeated to step wise increase the diameter of burr 726. It can be appreciated that burr 726 can be kept from rotating during indexing by engagement with sheath 718 or the vessel or vessel lesion. When drive shaft 720 is rotating in the opposite direction to engage teeth 802 and 806 along longitudinally extending surface 810, burr 726 can be rotated to ablate a lesion.
The diameter of burr 726 can be reduced by merely withdrawing it at least in part into sheath 718. Burr 726 can be withdrawn into sheath 718 sufficiently such that teeth 802 and 806 will be unmeshed. When teeth 802 and 806 are unmeshed, drive shaft 720 can be rotated to advance stop 747 to sleeve 745. At that point, burr 726 is reset to index from its smallest indexing diameter to its largest as described above.
Numerous advantages of the invention covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts without exceeding the scope of the invention. The inventions's scope is, of course, defined in the language in which the appended claims are expressed.
23. A catheter assembly, comprising:
- an elongate drive shaft having a proximal end and a distal end; and
- an ablation burr eccentrically connected to the drive shaft at the distal end thereof.
24. The catheter assembly in accordance with claim 23, further comprising a counter weight connected to the burr.
25. The catheter assembly in accordance with claim 23, wherein the burr includes an abrasive surface.
32. A method of removing lesion material from a patient's blood vessel, comprising the steps of:
- routing a catheter through a blood vessel having a central axis, the catheter including an elongate shaft having proximal and distal ends and defining a drive shaft lumen, a driveshaft having proximal and distal ends disposed in the drive shaft lumen, an ablation burr disposed on the distal end of the driveshaft for rotation therewith, and first and second inflation balloons disposed eccentrically on the shaft proximate the burr, wherein inflation of the first balloon urges the ablation burr in a first direction transverse of the central axis of the blood vessel and inflation of the second balloon urges the ablation burr in a second direction transverse of the central axis of the blood vessel;
- inflating the first or second balloon to urge the ablation burr in a direction transverse of the central axis of the blood vessel and into contact with lesion material deposited on a sidewall of the blood vessel; and
- rotating the burr.
33. The method of claim 32, further comprising:
- deflating the first or second balloon; and
- inflating the other of the first or second balloon to urge the ablation burr in another direction transverse of the central axis of the blood vessel.
34. The method of claim 32, further comprising supporting a proximal end of the ablation burr.
35. The method of claim 32, wherein the first and second balloons are disposed on opposite sides of the shaft.
36. The method of claim 32, wherein the catheter further includes a bearing positioned at the distal end of the shaft, the bearing defining a bearing surface that is capable of supporting a proximal end of the ablation burr.
37. The method of claim 36, wherein the bearing is cup shaped.
Filed: Mar 1, 2005
Publication Date: Jul 7, 2005
Inventors: Bill Kanz (Sacramento, CA), Denise Drummond (North Ogden, UT), Robert Barry (Kirkland, WA), Paul Hirst (Liberty Lake, WA), Mark Wyzgala (Bellevue, WA), Gary Swinford (Issaquah, WA), Edward Wulfman (Woodinville, WA), Tom Clement (Redmond, WA), Tom Kadavy (Bellevue, WA)
Application Number: 11/070,446