JP2002538876A - Shielded atherectomy device - Google Patents

Abstract

SUMMARY The present invention generally relates to devices for treating and removing occlusive substances from body lumens (eg, blood vessels). In particular, the present invention is a traumatic atherectomy device (10) having a shear body (300) contained within a substantially foam mounting housing (200), the housing (200) having an opening (204). , Through which occluded tissue may protrude into the interior of the housing (204) and may be engaged by the shearing body (300) rotating therein. The shears (300) have teeth (304), flutes, which are of helical design and have cutting lines.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] This application is related to US patent application Ser. No. 09 / 338,3, filed on Jun. 22, 1999.
02, which is a continuation-in-part application of U.S. Provisional Application No. 60 / 124,419 filed March 15, 1999;
No. 0 / 120,663; and No. 60/1 filed on Dec. 23, 1998.
No. 13,651 claims the benefit of 35 U.S.C. 119 (e), the complete disclosure of which application is hereby incorporated by reference in its entirety for all purposes. Have been.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to devices for treating and removing occlusive substances from body lumens (eg, blood vessels). In particular, the present invention relates to an apparatus and method for guided atherectomy using a catheter having a shear, the shear being surrounded by a housing or screen.

2. Description of the Background Art To remove stenosis or occlusive substances from blood vessels and restore sufficient blood flow to the blood vessels,
Numerous methods and devices are currently utilized. One common procedure is known as percutaneous transluminal angioplasty (PTA), where a catheter with a dilatation balloon at its distal end is positioned in a blood vessel at the site of the stenosis. The balloon is then used to restore sufficient blood flow to the area beyond the stenosis,
It is enlarged and dilates blood vessels.

[0004] Although PTA is often effective, it has certain limitations. For example, PT
A can be effective only if the occluding material in the blood vessel has enough openings to position the balloon inside the occluding material. When the vessel is almost completely occluded, it is difficult, if not impossible, to position the balloon of the catheter inside the occluding material. In addition, PTA has a variety of post-procedural and post-procedural problems: sudden closure, elastic recoil, and restenosis. Sudden closure is a rapid re-occlusion of the vessel within the time of the initial treatment. Sudden closure may result from rapid thrombus formation in response to damage to the vessel wall from PTA treatment. Elastic recoil is the elastic recovery of a dilated blood vessel approaching its pre-procedure diameter. Restenosis is the restenosis of blood vessels over weeks or months following an apparently successful initial PTA treatment. Restenosis occurs in up to 50% of all PTA patients and results from smooth muscle cell proliferation and migration and remodeling.

[0005] To address the problems of sudden closure, elastic recoil and restenosis described above, a vascular stent is implanted inside a blood vessel at the treatment site following a PTA procedure. These stents are thin-walled scaffolds that expand at the treatment site and act as a mechanical support for the lumen wall of the blood vessel, thereby preventing elastic recoil. Although this stent reduces the remodeling contribution to vessel narrowing, restenosis still occurs frequently in the stented area of the vessel. This is because most stents include an open lattice, where cell growth (often called hyperplasia) can occur in the gaps between the support elements of the lattice. as a result,
Instead of creating a barrier to hyperplasia and restenosis, the stent can be embedded within a thrombus and accumulated mass of tissue, and the treatment site again narrows.

[0006] Since the stent is an open lattice or scaffold-type device, deployment of the guidewire through the stented area must be done with particular care so that the guidewire does not penetrate through the open lattice of the stent. In such a case, an atherectomy device traveling down the guidewire path will face the stent and not only will severely damage the stent, but will also cause trauma to the blood vessel. Assuming that the guidewire is correctly deployed in the blood vessel, using the atherectomy device inside the stented area ensures that the atherectomy device is not positioned too close to the stent to damage the stent. , And not to injure the blood vessels,
Special care must be taken.

[0007] The treatment of an occluded stent is further complicated by facing all of the difficulties described above for treating an initial occlusion and the need to ensure that the stent is not damaged during removal of the hyperplastic occlusive material.

[0008] Rotating atherectomy devices (eg, Intervention Tech)
nologies of San Diego, a Tr from California
anal Extraction Catheter, and Bo
Stone Scientific of Bellevue, Washington
The Rotablator manufactured by On has limited success in stented blood vessels and faces additional challenges in removing stenotic tissue without interacting with the stent itself. Interaction of the spin removal device on a thin metal scaffold can cause severe complications during a medical procedure.

[0009] Therefore, there remains a need for improved methods and devices for treating and removing occlusive materials from blood vessels. In particular, an apparatus and method for removing material from an almost completely occluded blood vessel, wherein the device is capable of treating a stented blood vessel in a lumen without damaging the blood vessel and which can be safely achieved as quickly as possible. It is desirable to provide devices and methods that can remove stenotic tissue. Also, if the atherectomy device accidentally or intentionally contacts the stent during the atherectomy procedure, it is desirable to be able to work with the atherectomy device within the stented vessel so as not to damage the stent. Desirably, the devices and methods of the present invention are simple to implement, pose an acceptable risk to the patient, and are easily implemented by physicians familiar with balloon angioplasty and other conventional endovascular treatments Is done. At least some of these objectives will be met by the embodiments of the present invention described below.

SUMMARY OF THE INVENTION [0010] The present invention relates to the removal of stenotic material from unstented vessels as well as the removal of stenotic material in stents. The device has a longitudinal axis and defined proximal and distal ends. For the purposes of discussion, this proximal end is defined as
The side closer to the physician using the device and the distal end is the side farther from the physician. The device includes a rotatable shear and a housing, which acts as a sheath for the rotatable shear. The shear is held in place by a series of bearing surfaces between the shear, the housing and the restraining collar.
The present invention relates only to an atherectomy device located at the distal tip of a catheter. This device is designed for use at the tip of a catheter and mainly
Designed for interventional cardiac procedures. The atherectomy devices described herein, in some embodiments, all relate to a shielded atherectomy device or a screen for use with an atherectomy device.

The rotatable shear has a curved distal end. This distal end has a center in the shape of a collar or ring recess. The proximal end is generally cylindrical.
The lumen extends from the distal end to the proximal end along its longitudinal or central axis. The curved distal end has a bearing surface along the center and the curved distal end. Slightly behind this center, between the teeth of this shear,
A plurality of spiral flutes are formed. The spiral flute is designed to act as an impeller during rotation of the shear. Preferably, the helical teeth have a positive rake angle. The torque transmitting device transfers rotational energy directly to the shear body, resulting in the actively moving element of the present invention.

[0012] The housing has a curved distal end and a generally cylindrical proximal end. The housing is designed to cover the rotatable shear. The housing has a container that mates with the center of the shear, or as such, has a center that can accommodate the shear. The distal end has a smooth interior, which acts as a distal bearing surface and carries a portion of the shear body load. This center also carries part of the load of the shear. On the proximal end, the restraining collar maintains the correct alignment of the shear proximal end and acts as a proximal bearing surface for the shear proximal end. The restraining collar can be a lip or step inside the proximal end of the housing, or an additional piece (eg, a ferrule). The exterior of the housing proximal region is tapered to accommodate the catheter. Alternatively, the ferrule or equivalent can be provided to receive the catheter, and the ferrule can then be joined to the housing. The housing has at least one opening through which occluded tissue can protrude into the interior of the housing. The opening in the housing is angled approximately 45 degrees away from the main axis of the removal device.

[0013] The openings are arranged to cooperate with the teeth of the shears.
The minor axis of the opening is designed to be so narrow that when the stent strut or guidewire is substantially parallel to the minor axis, the strut or guidewire does not protrude through the opening. Due to this relationship, the teeth of the shear body may have a long front end, which is parallel to the short axis and never makes contact with the medical device, and therefore the stent strut or guidewire Eliminates the risk of accidental disconnection. The major axis of the opening projects parallel to the major axis, which is sufficient for the stent strut or guidewire to contact the shear. However, the shears operate in a circular path about the major axis of the shears, and the front ends of the teeth push the other medical device (eg, stent strut or guidewire) out of the opening rather than cutting it. Act as. In this way, the present invention can operate safely within the envelope defined by the stent and can safely remove tissue that swallows the stent. Tissue removal occurs when the front ends of the teeth either pinch tissue protruding into the housing, or cooperate with openings from body lumens to "scissors" tissue.

The principles utilized in forming this primary embodiment also result in some viable alternative embodiments.

In a second preferred embodiment, a screen is disclosed that is connected to a rotary shear. The screen has a gap zone defined by a distal end, a proximal end, and a space between the distal and proximal ends. The screen is manufactured from a substantially inflexible housing, which is concentric with the rotary shear when coupling the screen with the rotary shear. The screen has an internal chamber with an inner wall shaped to closely cover the shears. The gap zone of the screen has a plurality of openings to expose the shear surface of the shear. The screen has a first bearing surface at its distal end and a second bearing surface at its proximal end. The first and second bearing surfaces cooperate with corresponding bearing surfaces on the shear to maintain the screen in a fixed concentric arrangement with respect to the shear. The second shear surface has an extended lip or ring for attaching the screen to the catheter so that the screen does not rotate.

A third embodiment includes a screen that connects to a catheter having an axially movable shearing device. The screen has a distal end, a proximal end, and a gap zone between the distal and proximal ends. The screen is manufactured from a substantially inflexible housing having a central axis parallel to that of the catheter to which it is attached. The screen has an internal chamber with an inner wall shaped to closely cover the shearing device. The gap zone has a plurality of openings therein exposing the shearing device. The first mounting surface is on this screen,
It is located distally from the shearing device and the second mounting surface is located proximally from the shearing device. The first and second mounting surfaces hold the screen to the catheter while the shearing device slides within the screen interior chamber.

Additional alternative designs of the present invention are also disclosed, as are systems, methods of manufacture and methods of use that include the present invention. The present invention will become more fully understood upon consideration of the detailed description of the invention and the appended claims.

DESCRIPTION OF SPECIFIC EMBODIMENTS The following detailed description is of the best currently contemplated mode of carrying out the invention. This description is not to be construed in a limiting sense, but merely for purposes of illustrating the general principles of embodiments of the present invention. The scope of the present invention is best defined by the appended claims. In some instances, detailed descriptions of well-known devices, compositions, components, mechanisms, and methods are omitted so as to obscure the description of the present invention, including unnecessary details.

As used herein, the terms “occlusive” and “stenotic” substances refer to any proliferative or abnormal tissue or substance that occupies the lumen, and interfere with the normal functioning of the lumen Represent an object. “Occlusion” and “stenosis” materials may include thrombus, embolism, atheroma, atherosclerosis or hyperplasia of smooth muscle cells,
It is not limited to these.

“Medical device” is considered to be any artificial structure intentionally placed in a body lumen. In general, medical devices used in conjunction with atherectomy procedures include stents, guidewires, and various types of catheters. The design of the present invention is:
In the presence of any of these other medical devices, it is intended to allow safe removal of occluded tissue in body lumens, and in particular, the present invention is particularly well-suited for removing occluded tissue after swallowing a stent. Are suitable. The discussion herein includes reference to "stent loops." This reference applies to the orientation of the wire framework used to manufacture the stent. When a stent is deployed in a blood vessel, usually by balloon angioplasty, the balloon scaffold expands to match the outer diameter of the balloon used to deploy it. The expanded grid has a structure in which the wireframe or scaffold is arranged in a loop. The width of these loops is referred to herein as a "stent loop" and is used to determine the appropriate opening size.

Many terms used herein can be found in any mechanic's handbook.
The terms used to describe the preferred embodiment are the same terms that are commonly used to describe a grooved cutter, such as a dental bur.

The following additional definitions are specific to the present invention, which are briefly discussed herein, and are used herein in the context of the remaining detailed description and throughout the claims. Is done.

“Gap zone” is the area between the distal bearing or mounting surface and the proximal mounting or bearing surface. It is the part of the screen that has an opening that exposes the shield on the screen to a blood vessel or body lumen. During operation of the present invention, atherosclerotic tissue invades through the openings in this gap zone,
The shears in the screen or housing remove them from the body lumen.
This gap zone is easily identifiable by a number of openings or windows which create this area of the screen or housing, the appearance of which is similar to a cheese grater.

“Effective shear plane” or “effective shear surface area” means the area of the shear body that is exposed to tissue as it enters the gap zone through the opening. The effective shear plane includes areas of the shear body that may not perform any removal of tissue invading through these openings. However, if these areas are exposed to the opening of the gap zone, they are considered part of this effective surface area.

The “profile” of the shear is defined by the shape of the shear along its largest dimension during rotation. In the case of a flute-like cutter, for example, the profile of the shear body is the profile of the area created by the cutter during rotation from tooth to tooth, and not while stationary (from tooth to flute) .

“Gap space” is the space between the inner wall of the screen or housing and the profile of the shear.

“Mounting screen” is a screen or housing that has an external profile of approximately the same shape as the shear body it surrounds.

(1. Shear Body with Opposing Diagonal Slot Housing) Turning now to the drawings, FIG. 1A is an exterior view of the present invention. The present invention
Provided is an apparatus 10 for use in treating and removing occluding material from blood vessels or other body lumens of an animal or human. Apparatus 10 includes a rotating shear body 300, which is secured within housing 200. Device 204 in housing 200
Is shaped and angled so that tissue can protrude into housing 200 while prohibiting alignment of the medical device protrusion with a single axis. In this way, the shears 300 will not hit the medical device in a manner that can still cut or damage the device while still allowing for removal of protruding tissue. The non-parallel arrangement of the anterior edge (see below) and the main axis 14 of the opening 204 creates a new aspect of this design,
This is called the operation angle 150. Shear body 300 has a central portion 302 that fits through receptacle 202 in housing 200. The area of contact between the center 302 and the receptacle 202 is preferably electropolished or electroplated to reduce friction. The center 302 and the receptacle 202 must have very tight tolerances, so that the shears 300 may rotate within the housing 200, but the tolerances may not 12 must be sufficient to prevent vibrating. The proximal end of shear body 300 has a counterbore 322 (see below) that houses torque shaft 104.
The counterbore 322 is designed to have very tight tolerances with the torque shaft 104 so that there is little play in the axial movement of the shear body 300 during operation.
As the actual length of the torque shaft 104 can vary under operating conditions, the restraining collar 405 provides for movement of the shear body 300 along the axis 12 while the proximal end of the housing 200 prevents lateral vibration of the shear body 300. Is preferred to limit All surfaces where the shears actually make contact with the housing 200 or the restraining collar 405 are considered bearing surfaces. The bearing surfaces are preferably electropolished or electroplated to reduce friction, however, the present invention is known to operate without such features. The constraint collar 405 is the ferrule 4
00 or an alternative to the unitary housing 2004 (see below).
0 axis motion is controlled. The catheter jacket 112 may be mounted on the proximal side of the device 10, whether on the proximal surface of the housing 200 or a separate ferrule 400 may be mounted on the proximal end of the housing. The accompanying drawings include a spindle indicator 12, the arrow of which always points towards the distal end of each component.

FIG. 1B is a three-dimensional cutaway perspective view of the present invention. Apparatus 10 includes three elements. Housing 200 including shear body 300 and ferrule 400 acts as a restraining collar. The housing 200 has a plurality of openings 204 through which occluding material in a body lumen may protrude into the interior of the housing 200. Occlusion material (not shown) projecting through the opening 204 is sheared by the teeth 304 or by the cooperative action of the teeth 304 and the edges of the opening 204. Catheter 10
0 is mounted on the proximal end of the ferrule 400 up to the annular lip 404. The catheter has a torque shaft 104 and a mechanism for removing tissue (eg,
(A screw pump 106 or a vacuum pump). Catheter lining 110 and polymer jacket 112 help secure the outer surface of catheter 100 to ferrule 400 by any means known in the art. Guide wire 6
01 extends along the main axis 12 from the lumen 102 of the torque shaft 104 through a shear body lumen 320 (see below). Preferably, the torque shaft 10
4 has a liner 108 that shields the guidewire 601 from friction when the torque shaft 104 is rotating. Housing 200 has a receptacle 202 that engages central portion 302 of shear body 300. However, the relative positions of the two elements can be switched without changing the effectiveness of the device 10.

FIG. 1C shows that the catheter 100 can engage the device 10 by securing the proximal end of the housing 200. The catheter 100 is
It is composed of several layers. Torque shaft 104 has a polymer jacket 112 that extends axially through catheter 100 and covers the exterior thereof. Torque shaft 104 is shown extending through the central lumen of device 10. Torque shaft 104 passes through the proximal end of housing 200 and ferrule 400 (
Alternatively, it engages with the shear body 300 through the restraining collar 405). The torque shaft 104 can rotate freely within the housing 200 and the ferrule 400,
It is important that it can be fixed to the shear body 300.

It can be seen that shear body 300 is located at the distal interior of housing 200 and ferrule 400 appears to be in contact with shear body 300 within ferrule 400. In fact, there is a small gap 50 between the shear body 300 and the ferrule 400. The gap 50 is a gap generated during operation. The torque shaft 104 does not seem to maintain a completely constant length during operation. Therefore,
It is expected that there will be a small space between shear body 300 and ferrule 400.
The gap 50 is preferably about 0.002 ″, but the torque shaft 104
May be larger or smaller, depending on the length change of The shear has a lumen 320 extending therethrough, which, on its proximal side,
It gradually expands to a counterbore 322 that meshes exactly with the torque shaft 104. The counterbore 322 can be any mounting or coupling means that can secure the torque shaft 104 to the shear body 300. Such connecting means,
There are many ways of making this connection, rather than the inventive concept in device 10, which are well known in the art. At the distal end of device 10, shear body 300 has a central portion 302, which extends at least partially through housing receptacle 202. The combined mounting with the center 302 and the counterbore 322 should have very tight tolerances so that the shears 300 remain in proper alignment during rotation. The annular space 44 on either side has 0.
It should be no greater than 050 ", preferably less than 0.002". Therefore, its vibration tolerance is less than or equal to the annular space 44. Center part 302 and receptacle 2
02 and the combination of ferrule 400 (or restraining collar) and torque shaft 104 all contribute to maintaining the position of shear body 300. It should be noted here that complete alignment of this shear within the housing 200 is not possible during operation. A change in the length of the torque shaft 104 automatically creates a gap 50, wherein the bearing surface cannot engage the shear.
Thus, it must be understood that any variation up to the annular space 44 is considered normal by the present invention. In some cases, the vibrations are
And the device 10 is still functioning.

FIG. 2A shows an oblique arrangement of the main shaft 12 and an opening angle 148 of the main shaft 14 of the opening 204.
, And the cutting angle 149 of the cutter shaft 16 of the tooth 304. Here, the sum of the opening angle 148 and the cutting angle 149 constitutes the operation angle 150. In a preferred embodiment, the operating angle 150 is between 15 and 90 degrees. Opening angle 148
May not be equal to the cutting angle 149. Therefore, the relative operation angle 150 with respect to the main shaft 12 need not be at the center. 2B and 2C show that the operation angle is 1
Variants for cases as small as 5 degrees and as large as 165 degrees are shown. This preferred embodiment has an operating angle close to 90 degrees, if possible. Between 15 and 165 degrees, shallower and wider angles are operable, but are not as effective. The actual shape of the opening 204 can vary from device to device,
In general, it must have a major axis identified as the spindle 14. The spindle 14 is a line that can be drawn through the opening 204, regardless of its shape, confirming the orientation of the spindle on this housing. 2D-2F show three variants of the opening shape and the main axis 14 of each opening 204. FIG. The minor axis of the opening 204 may be equal to or less than the tangent of the inner diameter of the housing 200 over the outer diameter of the housing 200. This prevents the linearly lying object from projecting into the housing over the short axis if the object is not flexible relative to the hardness of the housing 200.

FIG. 3A is a perspective view of a preferred shear body 300 used in the present invention. Spindle 1
2 defines the distal end of the shear body 300. The center 302 is the housing 2
00 to engage with the receptacle 202. Distal end 310 is a curved, bearing surface for shear body 300. The shear body 300 has a plurality of spirally-shaped flutes 308. The leading edge of the tooth 304 engages and shears any tissue protruding into the housing. The upper part of the tooth 304
It has a radial land 306, which helps the medical device be pushed out of the path of the next tooth coming out during rotation. In addition, the teeth 304 may themselves act as a kind of bumper, pushing the medical device out of this opening, thus preventing the medical device from being cut. Near the proximal end of the tooth 304 is a descending region 314 that ascends the annular space 44 between the shears 300 and the housing 200.

FIG. 3B shows a proximal view of shear body 300. The main shaft 12 can be seen in the center of this part. The helical flutes and teeth have a positive rake angle 334 in a preferred embodiment. The rake angle 334 is determined by the relative line drawn through the radius 330 of this shear and the line of extension from the edge of each tooth 332. Although both intermediate and negative rake angles are operable, at present it is believed that the best configuration uses a positive rake angle. Guidewire lumen 32
A zero may be found at the center of shear body 300, with an enlarged opening serving as counterbore 322.

FIG. 3C shows a cross-sectional profile of shear body 300. Guidewire lumen 320
May appear to be unfolded to expose the counterbore 322, in which case the torque shaft 104 is fixedly mounted.

FIG. 3D is the complete profile of the shear used in most of the accompanying drawings. FIG. 3E shows a shear with a steep helical pitch in its flute, and FIG. 3F shows a shear with less teeth 304. The helical pitch of this shearing body is
It can vary from 0.010 "to 1.000" (inch). Since this pitch is the length along the cylinder, the path of the flute is withdrawn until a full swivel of the cylinder occurs. FIG. 3G shows an alternative design of the present invention, in which the shear has an abrasive surface at its distal end.

FIG. 4A shows an enlarged view of the ferrule 400. An annular lip 404 is seen separating the distal side of the ferrule, and a flow port 414 is located on the distal side.

FIG. 4B shows a unitary housing 2004 with an internal restraining collar 405. All other elements conform to corresponding features on housing 200 or ferrule 400.

FIG. 5 is an exploded view of the apparatus 10 before final assembly. The distal end of each component follows an axis line 12. Torque shaft 104 extends through ferrule 400 and engages shear body 300. Shear body 300 is pushed into the distal interior of housing 200, where the bearing surfaces help maintain the position of the shear body. Polyester heat shrink tubing 115 is placed over annular lip 404 of ferrule 400 to connect catheter 100 to ferrule 400 and housing 200.
To secure.

FIG. 6A is a plan view of a screen 500 that closely covers the shears. Screen 500 follows central axis 12, with distal end 520 pointing in the same direction as central axis 12. The screen 500 has a distal end 520 and a proximal end 530, and a gap zone 540 is located between the distal end 520 and the proximal end 530. Within the region of the gap zone 540, a plurality of openings 504 are arranged in a series of transverse rings around the central axis 12. Although the openings 504 can be arranged in almost any conceivable manner, preferred embodiments use the first lateral ring 506 of the opening 504 located as close as possible to the distal end 520. If it is desirable to add lateral rings of openings, they are called second rings, third rings, etc. As used herein, the designation refers to the most distal lateral ring as the first ring, and all subsequent rings follow naturally. Subsequent transverse rings 508, 510, 512 of the openings are staggered to maximize the number of openings 504 that can fit in gap zone 540. The number of horizontal rings or openings is not constant and the pattern of openings 504 is
It can be any desired that fits physically in gap zone 540 without critically reducing the intensity of zero. It is also contemplated to have staggered or stepped spacing between these transverse rings. Generally, the first lateral ring 506 is
00 should be located as close as possible to this distal end to ensure that as much of the occluding material invades internal chamber 550 as 00 is advanced.

The placement and approach of the openings 504 depends on the gap zone 540 and the struts 514 (
These must balance the strength of screen 500 at each opening 504). Each strut 514 also has the narrowest area of width 516, where the openings 504 are closest together and the structural integrity of the screen 500 is weakest. In particular, the integrity of the screen 500 at the gap zone 540 can be improved by making the screen 500 of a harder material. Preferably, stainless steel is used to make screen 500. However, other materials such as tungsten carbide, titanium and ceramics (natural and synthetic, such as sapphire) can be used. Finally, the hardness of the screen 500 depends on the hardness of the shear body 300.

To increase the life of the screen 500 and reduce the risk of breaking the screen 500 during operation, the relative hardness of the shears 300 preferably does not exceed the hardness of the screen 500. More preferably, the hardness of the screen 500 is equal to or higher than the hardness of the shear body 300.

The size of the opening 504 reflects the environment of the screen 500 to be used. There is no limit on the maximum size of the opening 504 except for what the gap zone 540 can accommodate. However, for coronary applications where the stent is to be deployed and used within the body lumen 320, the opening 504 is sized such that the largest diameter of the opening 504 is smaller than the stent loop that makes up the basic scaffolding structure of the stent. Should be. The presently preferred embodiment has a width greater than the width of the deployed stent loop by 0.3 mm.
An opening 504 sized to 001 ″ (one thousandth of an inch) is used.

In a preferred embodiment, the screen has a first row of openings 506 with a diameter of 0.010 ″. The first horizontal ring has 11 openings. There are three rows with eleven openings, in order to maintain the post width at the narrowest point between the openings, the second, third and fourth rows of openings are 0.01
2 "diameter. The size of the opening 504 is based on two competing criteria. The first criterion is to create a gap area sufficient to penetrate the internal chamber 550 for removal by the shear body 300. The second criterion is the need to lock out the stent loops from the inner chamber 550 so that the stent loops cannot interact with the shears 300. For each available or viable stent loop. It is not possible to elaborate the breadth sufficiently, however, given the significant portion of the market share of the stent, the aperture chosen to balance the two competing benefits of the preferred embodiment. The size of the opening 5 is 0.015 ″ or less.
04. The wall thickness of the screen 500 along this gap zone is 0.002 "with a tolerance of +/- 0.001". This distal end has a bearing surface that includes a protruding receptacle that houses the distal bearing surface of shear body 300, as described above. In order to maintain the typical width of a coronary catheter, the diameter of this screen is typically 0.06 "+/- 0.02".
The diameter of the shear body 300 disposed within the screen 500 necessarily is adapted to match the internal chamber of the screen 500.

In the current embodiment, this distal end has a length of 0.004 ″ +/− 0.003 ″ and is about the same length as the central portion 502 that houses the bearing surface of the shear body 300 It is. The length of this proximal end varies with the number of transverse rings in gap zone 540. Shear body 354 (or ferrule 400 mounted on shear body 300)
There is no minimum length for this proximal end, as long as there is sufficient surface area to allow the proximal bearing surface of the toe to center shear body 300 with respect to screen 500.

FIG. 6C illustrates an alternative embodiment of a screen 500 having three rows of openings, where the size of the openings is 0.015 ″ in the first horizontal ring and the second horizontal ring. And in the third row, 0.020 ". FIG. 6D shows yet another embodiment having eight rows of transverse rings, where the first transverse ring has a 0.004 "diameter opening. The second row has a 0.005" diameter opening. The third lateral ring has a 0.006 "diameter opening and the remaining lateral ring 521x
Has an opening with a diameter of 0.007 ". Again, each lateral ring has an effective shear plane 350 of the shear body 300 to maximize the available opening space 504.
Is then made up with a ring that is directly distal from it. The width of the screen post 316 in this embodiment is reduced to 0.001 "and the material of the housing is preferably tungsten carbide or titanium.

FIG. 7A is a cutaway view of the screen 500 and shear body 300 displaced therein. Screen 500 has an internal chamber 550 that closely covers shear body 300. Shear body 300 has a distal bearing surface 352 and a proximal bearing surface 354. There is an effective shear plane 350 between the distal bearing surface 352 and the proximal bearing surface 354. The gap zone 540 of the screen 500
Over the shear body 300, it may have the same dimensions as the effective shear plane 350. However, the present invention works equally well if the effective shear plane 350 is smaller or larger than the gap zone 540. Distal end 52 over effective shear plane 350
A small overlap of zero or the proximal end 530 is also acceptable.

FIG. 7B illustrates the bulge of the cross section of the screen 500 and the shear body 300. The gap defined by the space between the effective shear plane 350 and the inner wall 552 of the gap zone 540 is the gap space 554. The gap space 554 preferably simultaneously maintains close proximity to effectively “sciss” tissue that invades the interior chamber 550 during operation, while preferably maintaining the inner wall 552 of the gap zone.
In order to rotate the shear body 300 within the screen 500 without interacting with the In the present invention, the gap space 554 is preferably radially less than 0.002 ″. For the screen 500, the shear 3
00 may be of the type having teeth and flutes as described above in FIGS. 3A-G, or it may be of the type shown in FIGS. 9A-B (below). Screen 5
The contour of 00 should follow the profile of shear body 300. If shear body 300 can be tapered on its proximal bearing surface 354, screen 500
Should also taper down on the proximal end 530.

3. System with Safety Screen and Diagonal Housing FIGS. 8A-B illustrate a system 800 of the present invention. System 800 includes:
It includes a catheter 100 having a shear body 300 at its distal end, and a screen 500 covering the shear body 300. Guidewire 601 is shown as well. The distal end of the catheter 100 may use any of the shear and housing or shear and screen embodiments described herein. Most atherectomy device uses include a motor drive unit MDU, a vacuum pump VP and a receptacle R for the removed occlusion material. These additional elements are provided here merely as examples and should not be considered as part of the present invention.

4. Prosthesis Embodiment FIG. 9 illustrates some prosthesis embodiments of a screen 500 used to closely cover an alternative shear. FIG. 9A illustrates an oblong rotating bar having a screen 500a attached thereto. This screen is a screen 500a
Can be manufactured using a swaging machine that imparts a curvature on the proximal end of the device, and according to the methods described herein. In this way, the screen can be accurately mounted on the rotating shears 300a. If necessary, depending on the curvature of the rotating bar / cutter, before swaging, the screen 500a
Relief slots can be created. FIG. 9B illustrates the screen 500b fixedly attached to the catheter 100 at the distal and proximal positions of the shearing mechanism. The screen 500b has a plurality of openings arranged in a rectangular pattern similar to a window. In this way, the screen 500b resembles the window of a directional atherectomy device. FIG. 9C illustrates a shear with flutes and a screen mounted directly on the shear along the radial lands of each tooth.

(5. Manufacturing Method) The following manufacturing method generally uses the screen 5 used when manufacturing the device 10.
This applies to both 00 and housing 200. Subtle changes in the manufacture of either screen 500 or housing 200 are noted at each particular step. For reference purposes, the method described herein refers to making the device 10, which includes a housing 200 with a shear body 300 as described in Section 1.
And screen 500 used to closely cover the shears described in Section 2. The term "screen" is used below in a generic way to describe screen 5
Used to mean either 00 or housing 200. The device 10 of the present invention can be manufactured in numerous ways. Currently, the best possible mode of making this screen is described in the following steps.

A. First Step-Making a Dimensioned Screen The screen 500 can be made from a mandrel or rod of stainless steel or other sufficiently hard material. Preferably, the mandrel is selected with a diameter that corresponds to the desired outer diameter of the screen 500 to be made. This mandrel is cut along the main axis 12 to a length corresponding to the length of the screen 500 to create a blank. The blank is secured to a fixture that holds it in place while using a custom radius tool to shape the distal end of the blank, and loaded into a lathe or chuck on a CNC machine. Once the distal end has been formed, the blank can be inverted and a custom end mill with the desired radius can be used to shape the interior chamber 550. The screen 500 can have a central portion 502, which can be made at the same time as the inner chamber 550, or separately after the inner chamber 550 is completed, using a different end mill.

B. Second Step-Creating the Opening Once the internal chamber 550 is completed, the screen 500 is reattached to a new mandrel that matches this internal chamber and has a profile that will withstand the load of the opening making process. A new mandrel is secured on the lathe or CNC machine stock and the desired pattern and size of the opening (204 or 5) is secured.
04), a correctly sized drill bit is used. The size of the opening is predetermined (eg, a stented lumen for native coronary artery disease) depending on the particular environment in which the screen will be used. A CNC device is preferred to more precisely control the spacing and orientation of the openings. Once these openings have been created, the screen is removed from its support mandrel and the screen is removed by installing a second end mill in the interior chamber and gently rotating the second end mill. It is deburred by removing bars or other particulates inside the inner chamber 550 without deforming. If necessary, the screen 500 can be installed in the support frame while performing this deburring step. Finally, the screen is electropolished to smooth any remaining rough edges. Although the method of the present invention uses classical mechanical cutting to produce this screen opening, other techniques such as laser machining, EDM (electric discharge machining) and optical machining to name a few. Engraving) is also possible.

C. Third Step-Assembling Screen and Shear Once the screen 500 is completed, the ferrule 400 is slid over the torque shaft 104. The screen 500 is then mounted on the torque shaft 10
4 directly attached to the end of the shear body, the shear body has a counterbore 32 in the shear body.
2 houses the torque shaft 104. Ferrule 400 is then advanced to the distal end of the torque shaft until it contacts shear body 300. Ideally, shear body 300 has a proximal bearing surface 354, which is
05 has an outer diameter that matches the diameter of the ferrule 400 on the distal side. The ferrule 400 is joined to the screen 500 while the shear and torque shaft rotate freely within the interior chamber of the screen. The distal bearing surface 352 and the proximal bearing surface 354 must maintain the shear in a concentric alignment with the screen while freely rotating the shear within the screen 500 at high speed. The screen and ferrule can be joined by solder, epoxy, laser welding or any other suitable method.

D. Fourth Step-Catheter Completion The polymer jacket 112 is fused along the proximal end 408 of the ferrule 400 over the outside of the ferrule 400. This polymer is preferably exuded into flow port 414 to help secure polymer jacket 112 to ferrule 400. In one aspect of the invention, the shrink heating tube 115 is melted over the joint, where the polymer jacket 112 is joined to the device 10. Heat shrink tubing 115 adds an annular strength to this joint to help secure catheter 100 to screen 500. The joining of the polymer jacket 112 to the housing 200 is such that during operation, the rotational torque causes the shears 3
Help keep from moving from 00. The catheter jacket 112 can be secured to the housing 200 by any means known in the art.
The ferrule 400 has an annular lip 404, which is used to improve the annular strength of the ferrule 400. The completed assembly (see FIG. 1A) completes the assembly of all aspects of the invention.

It will be readily apparent to one of ordinary skill in the art of machining and CNC machining that there are many alternative ways of making the present invention. The methods described above are not to be considered as limiting as the only way to make the invention.

While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The appended claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.

[Brief description of the drawings]

FIG. 1A is a side view of the present invention mounted on the distal end of a catheter.

FIG. 1B shows a cutaway perspective view of the present invention with a catheter and guidewire.

FIG. 1C is a cutaway side view of the present invention and catheter.

FIG. 2A shows the angles of various cooperating cutting elements.

FIG. 2B shows a minimum operation angle.

FIG. 2C shows the maximum operating angle.

2D-2F show three alternative designs of the housing opening.

FIGS. 2D-2F show three alternative designs of housing openings.

FIGS. 2D-2F show three alternative designs of housing openings.

3A to 3C show perspective, plan and side views of a shear body and its main components.

3A to 3C show perspective, plan and side views of a shear body and its main components.

3A-3C show perspective, plan and side views of a shear body and its main components.

3D-3G show four alternative shear designs.

FIGS. 3D-3G show four alternative shear designs.

3D-3G show four alternative shear designs.

3G-3G show four alternative shear designs.

FIG. 4A shows a ferrule for use with a separate restraint device.

FIG. 4B shows a unitary housing design.

FIG. 5 presents an assembly drawing of all the elements of the invention plus the torque shaft required to integrate this device.

6A-B show screens.

6A-B show screens.

6C-D illustrate two alternative screens.

6C-D illustrate two alternative screens.

7A-B are bulges of the attached screen and shear body assembly.

8A-B illustrate a system utilizing the present invention.

9A-C illustrate two alternative embodiments of the present invention.

9A-C illustrate two alternative embodiments of the present invention.

9A-C illustrate two alternative embodiments of the present invention.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CR, CU, CZ, DE, DK, DM, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID , IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, NO, (72) Invention NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW McFan, Tim United States California 94062, Redwood City, Viewway No. 7 (72) Inventor Forster, David United States California 94062, Woodside, Starhill Road 630 F-term (reference) 4C060 EE21 EE30 MM25

Claims (156)

[Claims] 1. A device for removing an occluding substance in a stent, the device comprising:
A rotary shear, wherein the shear is maintained in a rigidly secured axial arrangement within a rigid housing and a restraining collar, the housing having a plurality of oblique openings;
The opening protrudes an occluding material through the device when the housing is pressed against a body lumen, the shear body has a plurality of teeth, and the teeth protrude into the housing. An apparatus having an array that is not parallel to the oblique opening to sever material and prevent cutting of the medical device. 2. The shear body further includes a curved distal end, a bearing surface, an outer surface, and an interlocking joint, the distal end extending through a central portion, a generally cylindrical proximal end, and therethrough. A bearing surface formed on the distal end, the outer surface having a plurality of helical flutes between the teeth, wherein the flutes rotate the shear body. The apparatus of claim 1, wherein when engaged, the device is formed with a pitch angle that acts as an impeller, and the mating joint attaches the shear to a torque shaft. 3. The container, further comprising a curved distal end, a smooth inner bearing surface, and a generally cylindrical proximal end, the distal end mating with the center of the shear body. 2. The device of claim 1, wherein the proximal end has an outer surface, an inner surface, and a tapered region, the tapered region being near the proximal end for snugly receiving a catheter. Equipment. 4. The device of claim 1, wherein the teeth are arranged substantially perpendicular to a major axis of the device. 5. The apparatus of claim 1, wherein the oblique openings are preferably arranged at about 45 degrees from the central axis. 6. The apparatus of claim 1, wherein the cutting axis is preferably arranged at about 45 degrees from the central axis opposite the diagonal device. 7. The device according to claim 1, wherein the operating angle is preferably 90 degrees. 8. The device according to claim 1, wherein the operating angles are 15 degrees or more from each other. 9. The apparatus of claim 1, wherein the housing has a thickness of less than 0.050 "(5/100 inch). 10. The housing preferably has 0.0015 "and 0.0
The device of claim 1 having a thickness between 025 ". 11. The apparatus of claim 1, wherein the housing has an inside diameter of less than 0.500 "(half inch). 12. The apparatus of claim 1, wherein said housing is made from stainless steel. 13. The device of claim 1, wherein said housing is made of titanium. 14. The apparatus of claim 1, wherein said housing is made from a ceramic material. 15. The device of claim 1, wherein said housing is made of plastic. 16. The apparatus of claim 1, wherein said housing is made from a composite material. 17. The apparatus of claim 1, wherein the teeth of the shear have a positive peripheral rake angle. 18. The shear body may be 0.050 "(50/1000 inch).
The apparatus of claim 1, wherein the following annular space is spaced from the housing along the length of the flute of the shear body. 19. The apparatus according to claim 1, wherein an annular space separates the shear body and the housing, the annular space preferably being between 0.0005 "and 0.0015". . 20. The flutes of the shears may be 0.010 "and 1.000.
The device of claim 2 having a pitch between ". 21. The apparatus of claim 1, wherein the shears and the housing are of different material hardness. 22. The apparatus of claim 2, wherein the shear is soldered to the torque shaft. 23. The apparatus of claim 2, wherein the shear is chemically coupled to the torque shaft. 24. The apparatus of claim 2, wherein said shear body is laser welded to said torque shaft. 25. The apparatus of claim 2, wherein the shear body is secured to the torque shaft with an interference fit. 26. The apparatus of claim 1, wherein said housing is made from stainless steel. 27. The device of claim 1, wherein said housing is made of titanium. 28. The apparatus of claim 1, wherein said housing is made from a ceramic material. 29. The apparatus of claim 1, wherein said housing is made of plastic. 30. The apparatus of claim 1, wherein said housing is made from a composite material. 31. The device of claim 1, wherein the shears cooperate with the device to remove stenotic material from an area defined by the stent. 32. The restraining collar is a ferrule, and the ferrule is
An outer surface having a proximal end and a distal end separated by an annular lip, the distal end being fixedly mounted within the distal orifice, and the proximal end being attached to a catheter. The device of claim 1, fixedly mounted, wherein the ferrule further includes an inner surface, the inner surface defining a lumen through which the torque shaft can rotate. 33. The apparatus of claim 1, wherein said housing is made from stainless steel. 34. The apparatus of claim 1, wherein said housing is made of titanium. 35. The apparatus of claim 1, wherein said housing is made from a ceramic material. 36. The apparatus of claim 1, wherein said housing is made of plastic. 37. The apparatus of claim 1, wherein said housing is made from a composite material. 38. The apparatus of claim 32, wherein said ferrule is integrated on said proximal end of said housing. 39. The ferrule is fixedly mounted on the catheter, wherein the catheter has a sheath of a polymeric material, wherein the polymeric material is melted on the ferrule. 33. The device according to claim 32. 40. The apparatus of claim 2, wherein said torque shaft comprises braided tubing. 41. The apparatus of claim 2, wherein said torque shaft is a plurality of reverse-wound coils. 42. The apparatus of claim 2, wherein the torque shaft further comprises a Teflon tube, wherein the Teflon tube incorporates a wire braid and a polymer laminate. 43. The device of claim 1, wherein said medical device is an artificial structure. 44. A removal device for removing a stenotic substance in a stent, the removal device having a longitudinal axis, a proximal end and a distal end, the device comprising: A possible shear, comprising at least one flute arranged in a helical fashion relative to the longitudinal axis, a lumen extending therethrough through a guidewire, a central guide at the distal end, and A shear body having means for engaging said shear body with a torque transmitting device; a housing enclosing said rotatable shear body, said housing comprising a distal container containing a central portion of said shear body. Having a generally cylindrical shape with the housing having at least one opening for an occluding material for projecting into the interior of the housing, wherein the device is partially opposite the flute. Houses arranged at an angle And coupling means, said coupling means being attached to said housing such that said shearing body and said torque shaft can rotate freely within said housing and be properly maintained in an axial position relative to said housing. A connection means for mounting a catheter. 45. The housing may be 0.050 ”(5/100 inch).
45. The removal device of claim 44, wherein the removal device has a thickness of less than. 46. The housing, preferably comprising 0.0015 "and 0.015".
45. The removal apparatus of claim 44, having a thickness between 025 ". 47. The removal apparatus of claim 44, wherein the housing has an inner diameter between 0.500 "and 0.040". 48. The apparatus of claim 44, wherein said housing is made from stainless steel. 49. The apparatus of claim 44, wherein said housing is made of titanium. 50. The apparatus of claim 44, wherein said housing is made from a ceramic material. 51. The device of claim 44, wherein said housing is made of plastic. 52. The housing of claim 44, wherein the housing is made of a composite material.
An apparatus according to claim 1. 53. The removal apparatus of claim 44, wherein the teeth of the shears have a positive peripheral rake angle. 54. The removal device is spaced from the outer shell along the length of the flute of the removal device by an annular space of 0.050 ″ (50/1000 inch) or less. 45. The removal device of claim 44, wherein 55. The removal of claim 44, wherein an annular space separates the shears and the housing, the annular space preferably being between 0.0005 "and 0.0015". apparatus. 56. The removal apparatus of claim 44, wherein the housing is at least as hard as the shears. 57. The removal device of claim 44, wherein the housing is harder than the shears. 58. The removal device of claim 44, wherein the helical flute and the device are at a 90 degree angle with respect to each other. 59. The removal device of claim 44, wherein the helical flute and the device are at an angle of 15 degrees or more with respect to each other. 60. The removal apparatus according to claim 44, wherein the shear body is soldered to the torque shaft. 61. The removal apparatus according to claim 44, wherein the shear body is chemically coupled to the torque shaft. 62. The removal device according to claim 44, wherein the shear body is laser welded to the torque shaft. 63. The removal apparatus of claim 44, wherein the shear body has an interference fit with the torque shaft. 64. The apparatus of claim 44, wherein said housing is made from stainless steel. 65. The apparatus of claim 44, wherein said housing is made of titanium. 66. The apparatus of claim 44, wherein said housing is made from a ceramic material. 67. The apparatus of claim 44, wherein said housing is made of plastic. 68. The housing of claim 44, wherein the housing is made of a composite material.
An apparatus according to claim 1. 69. The removal device of claim 44, wherein the shears cooperate with the device to remove stenotic material from an area defined by the stent. 70. The removal device of claim 44, wherein the coupling means for mounting the catheter and the housing is located at the proximal end of the housing. 71. The coupling means is a ferrule, the ferrule having an outer surface with a proximal end and a distal end separated by an annular lip, wherein the distal end is the proximal end of the housing. A fixed end mounted within the distal end, and the proximal end fixedly mounted to a catheter, the ferrule further includes an inner surface through which the torque shaft extends. 46. The removal device of claim 44, wherein the device defines a rotatable lumen. 72. The apparatus of claim 44, wherein said housing is made from stainless steel. 73. The apparatus of claim 44, wherein said housing is made of titanium. 74. The apparatus of claim 44, wherein the housing is made from a ceramic material. 75. The apparatus of claim 44, wherein said housing is made of plastic. 76. The housing of claim 44, wherein the housing is made of a composite material.
An apparatus according to claim 1. 77. The removal device of claim 71, wherein the ferrule is integrated on the proximal end of the housing. 78. The ferrule is fixedly mounted on the catheter, wherein the catheter has a sheath of a polymeric material, wherein the polymeric material is melted on the ferrule. 72. The removal device according to claim 71. 79. The removal device of claim 44, wherein said torque shaft comprises braided tubing. 80. The removal device according to claim 44, wherein the torque shaft is a plurality of reverse-wound coils. 81. The removal apparatus of claim 44, wherein the torque shaft further comprises a Teflon tube, wherein the Teflon tube incorporates a wire braid and a polymer laminate. . 82. A removal device for removing a stenotic substance in a stented body lumen, the removal device having a longitudinal axis, a proximal end and a distal end, the device comprising: Includes: A rotatable remover that includes a polishing surface, a lumen extending therethrough for passage of a guidewire, a central guide at the distal end, and a torque transmitting device. A mating housing, wherein the housing is formed with a generally cylindrical cross-section and is shaped to cover the rotatable shear, wherein the housing exposes a spiral flute of the rotatable shear. At least one opening, a distal orifice containing the central guide, and a proximal orifice, the openings being arranged at an angle opposite the flute; Ah Thus, the coupling means attaches a catheter to the housing such that the shears and torque transmitting device can rotate freely within the housing and be properly maintained in an axial position relative to the housing. apparatus. 83. A screen connected to a rotary shear of the catheter,
The screen has a distal end, a proximal end, and a gap zone located between the distal end and the proximal end, the screen including the following parts: An interior chamber having an interior wall configured to be concentric with the rotary shear and to closely cover the shear when the screen is coupled thereto. And having a plurality of openings in the gap zone, the openings substantially exposing an effective shear surface area of the rotary shear body; (b) a first bearing surface; A first bearing surface is located at the distal end; and (c) a second bearing surface, wherein the second bearing surface is located at the distal end; The first and second bearing surfaces are concentric and fixed with respect to the rotational shear plane. A screen that maintains the screen in an array. 84. The screen of claim 93, wherein said inflexible housing is made from stainless steel. 85. The screen of claim 83, wherein said inflexible housing is made from titanium. 86. The screen of claim 83, wherein said inflexible housing is made from a ceramic material. 87. The screen of claim 83, wherein said inflexible housing is manufactured from a refractory metal. 88. The screen according to claim 83, wherein said housing is bell-shaped. 89. The screen of claim 83, wherein said housing is substantially football shaped. 90. The screen according to claim 83, wherein said housing is hemispherical. 91. The screen according to claim 83, wherein said housing is bullet-shaped. 92. The screen of claim 83, wherein the devices are arranged in the gap zone in a transverse ring around a circumference of the gap zone. 93. The screen of claim 83, wherein the devices are arranged in the gap zone in a helical pattern around the circumference of the gap zone. 94. The method according to claim 94, wherein the opening is 0.001 in the gap zone.
84. The screen according to claim 83, wherein the screen is spaced apart by at least ". 95. The screen according to claim 83, wherein said openings are preferably less than 0.015 ″ in diameter. 96. The screen of claim 83, wherein said openings are more preferably less than 0.0125 "in diameter. 97. The screen according to claim 83, wherein said opening of said gap zone is circular. 98. The screen of claim 83, wherein said openings in said gap zone are oval. 99. The screen according to claim 83, wherein said openings are slots. 100. A screen for connecting to a catheter having an axially movable shearing device, the screen comprising a distal end, a proximal end, and a gap between the distal end and the proximal end. With a gap zone, the screen includes the following parts: (a) a substantially inflexible housing, the housing having a longitudinal axis of the catheter when the screen is coupled thereto; An inner chamber having an inner wall having a central axis parallel to and having an inner wall shaped to closely cover the shearing device, and having a plurality of openings in the gap zone, wherein the opening comprises the shearing device. (B) a first mounting surface, wherein the first mounting surface is located at the distal end of the screen and at a point distal to the shearing device; Fixedly mounting the screen on; and (c) A) a second mounting surface, the second mounting surface being located at the proximal end of the screen, for securing the screen to the catheter at a point proximal to the shearing device; The screen. 101. The screen of claim 100, wherein said inflexible housing is made from stainless steel. 102. The screen of claim 100, wherein said inflexible housing is made from titanium. 103. The screen of claim 100, wherein said inflexible housing is made from a ceramic material. 104. The screen of claim 100, wherein said inflexible housing is made from a refractory metal. 105. The screen according to claim 100, wherein said housing is bell-shaped. 106. The screen of claim 100, wherein said housing is substantially football shaped. 107. The screen of claim 100, wherein said housing is cylindrical. 108. The screen of claim 100, wherein said housing is bullet-shaped. 109. The screen of claim 100, wherein said openings are arranged in said gap zone in equidistant rings around the circumference of said gap zone. 110. The screen of claim 100, wherein the openings are arranged in the gap zone in a spiral pattern around a circumference of the gap zone. 111. The method according to claim 111, wherein the opening is 0.00
The screen of claim 100, wherein the screen is spaced 1 "or more apart. 112. The screen of claim 100, wherein said openings are preferably less than 0.015 "in diameter. 113. The screen of claim 100, wherein said openings are more preferably less than 0.0125 ″ in diameter. 114. The screen of claim 100, wherein said openings in said gap zone are circular. 115. The screen of claim 100, wherein said openings in said gap zone are oval. 116. The screen according to claim 100, wherein said openings are slots. 117. The screen of claim 116, wherein the orifice slots are arranged substantially parallel to the axis of the catheter. 118. A shielded shear for use with a catheter, wherein the shielded shear includes the following: (a) a shear having a shear surface, wherein the shear is a distal end; Having a proximal end and a lumen extending therebetween; (b) a screen fixedly mounted to the shears, wherein the screen comprises:
A distal end, a proximal end, and a gap zone, wherein the gap zone is defined by a space between the distal end and the proximal end, has a plurality of openings, and closes the shear body. A shielding shear, wherein the inner chamber of the screen and the shearing surface define a gap space. 119. The shielding shear of claim 118, wherein the screen has a bullet-shaped external profile. 120. The shield shear of claim 119, wherein the external profile substantially conforms to the profile of the shear. 121. The screen has a wall thickness of less than 0.005 ″.
129. The sheared shear of claim 118. 122. The shield shear of claim 118, wherein the inflexible housing is made from stainless steel. 123. The shield shear of claim 118, wherein the inflexible housing is made from titanium. 124. The shield shear of claim 118, wherein the inflexible housing is made from a ceramic material. 125. The shield shear of claim 118, wherein the inflexible housing is manufactured from a refractory metal. 126. The shield shear of claim 118, wherein the openings are arranged in the gap zone in equidistant rings around the circumference of the gap zone. 127. The shield shear of claim 118, wherein the openings are arranged in the gap zone in a spiral pattern around the circumference of the gap zone. 128. The apparatus of claim 128, wherein the opening is less than 0.00 in the gap zone.
119. The shield shear of claim 118, spaced 1 "or more apart. 129. The shield shear of claim 118, wherein the openings are preferably less than 0.015 "in diameter. 130. The shield shear of claim 118, wherein said openings are more preferably less than 0.0125 "in diameter. 131. The shield shear of claim 118, wherein the opening of the gap zone is circular. 132. The shield shear of claim 118, wherein the opening in the gap zone is oval. 133. The shield shear of claim 118, wherein the opening is a slot. 134. The shield shear of claim 133, wherein the slots in the opening are arranged substantially parallel to the axis of the catheter. 135. The shield shear of claim 118, wherein the gap space between the screen and the shear is less than 0.0005 ″. 136. A system comprising: (a) a catheter having a distal end, a proximal end, and a lumen extending longitudinally therebetween; (b) A) a torque member, the torque member extending longitudinally through the lumen of the catheter, and having a lumen and a distal end; A rotary shear secured to the distal end of the torque member; and (d) a mounting screen for connecting to the rotary shear, the screen comprising a distal end, a proximal end, and the Having a gap zone located between a distal end and the proximal end, the screen includes a substantially inflexible housing, the housing having the screen connected thereto; , Concentric with the rotary shearing body,
An inner chamber having an inner wall shaped to closely cover the shear, and having a plurality of openings in the gap zone, wherein the openings substantially define an effective shear surface area of the rotary shear. Exposed, the mounting screen further includes a first bearing surface and a second bearing surface, wherein the first bearing surface is located at the distal end and the second bearing surface is A system, wherein the first and second bearing surfaces maintain the mounting screen in a concentric arrangement fixed relative to the rotary shear. 137. The system of claim 136, further comprising: (e) a guidewire. 138. The guidewire has a guide portion, the guide portion defining a curved three-dimensional profile diametrically greater than a width of the shear body;
The guide portion provides a curved path along which the shear body can be advanced, and the guide portion is made of a shape memory material and extends the guide portion through the lumen of the torque member. 138. The system of claim 137, wherein the system is sufficiently flexible to exhibit a substantially linear profile. 139. The system of claim 136, wherein said torque member can be advanced axially through said catheter. 140. The system of claim 136, wherein the torque member and the shear are separated by a ferrule, wherein the ferrule is adapted to couple the torque member and the shear together. . 141. The system of claim 140, wherein said ferrule acts as a proximal concentric bearing surface relative to said mounting screen. 142. The system of claim 140, wherein said ferrule acts as a proximal concentric mounting surface relative to said mounting screen. 143. The system of claim 136, wherein said gap space is less than 0.002 "radially. 144. The gap space is preferably 0.001 in the radial direction.
136. The system of claim 136. 145. The gap space, more preferably 0.0 mm in the radial direction.
137. The system of claim 136, wherein the system is less than 005 ". 146. The system of claim 136, wherein said mounting screen and said shears are made from materials having the same hardness. 147. The system of claim 136, wherein the mounting screen comprises a material having a hardness greater than a hardness of the shear body. 148. A method of manufacturing a mounting screen adapted to closely cover a shear body of a catheter, the method comprising the steps of: (a) determining the dimensions of the shear body. (B) determining an effective shear surface area of the shear body; (c) at least one having an internal profile that can be attached to the shear body and that closely matches an external dimensional profile of the shear body. (D) creating a distal bearing surface; (e) creating a proximal bearing surface; (f) creating a plurality of openings in the housing in the area of the housing. Thereby forming a screen from the housing, the area corresponding to the effective shear surface area of the shear body; and (g) the shear body being attached to the mounting screen. Operably planned without disturbing the down step of attaching the screen to the catheter. 149. The method of claim 148, wherein the housing of step (c) is more than one element. 150. The method of claim 148, wherein said openings in step (f) are formed by conventional machining. 151. The method of claim 148, wherein said opening in step (f) is formed by a laser. 152. The method of claim 148, wherein said openings in step (f) are formed by electrical discharge machining. 153. The method of claim 148, wherein the openings in step (f) are formed by water jet machining. 154. Step (g) is replaced by the following steps:
48. (h) polishing the opening; (i) attaching the screen to the catheter such that the shears can operate as planned without disturbing the mounting screen. 155. The method of claim 148, wherein step (g) further comprises attaching the screen to the shears. 156. The method of claim 148, wherein step (g) is accomplished by swaging.