1. Technical Field
The present disclosure relates to medical devices. More particularly, the disclosure relates to a cutting edge cutting catheter to treat peripheral chronic total occlusion (“CTO”).
2. Background Information
Peripheral chronic total occlusion (“CTO”) is when plaque accumulates in a blood or body vessel so no or little blood can flow through the vessel. This is often a very painful and dangerous condition, as it may cause ischemia in the extremities requiring invasive treatment.
Treatment for CTO is to clear the occlusion from the blood vessel. This may involve exercise, pharmacological methods, invasive surgery, or endovascular and interventional methods. However, traditional treatment methods may not be successful due to the nature of the occlusion. For example, a cholesterol crystal cap may form at the ends of the occlusion. This cap forms due to macrophage accumulation in an inflammatory response and an increase in retained Low Density Lipoprotein (“LDL”). This cholesterol crystal cap creates a hard surface that is difficult for the physician to maneuver through in order to clear the vessel.
One minimally invasive treatment method is the STAR (subintimal tracking and re-entry) method. This method involves using medical tools, such as a catheter, to maneuver from the true lumen of the blood vessel, through the intimal layer, into the subintimal space. Once the user or physician passes the occlusion by way of the subintimal space, the user maneuvers back from the subintimal space into the true lumen. At this point, the physician can access the occlusion.
Using the STAR method requires making fine maneuvers in the blood vessel with a high degree of precision at a position deep within the body. Any unintended cuts may create avoidable issues. Thus, there is a need for an improved device that can make these fine maneuvers to avoid unintended cuts.
The present disclosure generally provides a cutting edge cutting catheter or medical device suitable for peripheral CTO treatment. The present disclosure also generally provides a method for treating an occlusion within the blood vessel.
The device comprises an elongate member, a cutting edge, an extending member, a tension mechanism, and an expandable balloon. The elongate member may have a proximal end extending distally to a distal end, a circumference, and a plurality of lumens formed therethrough. The plurality of lumens comprising a cutting lumen, a balloon inflation lumen, and a wire guide lumen. The device further comprises a cutting edge slidably disposed within the cutting lumen and having an arcuate cross-section. The cutting edge arcuately extends circumferentially up to half of the circumference, and comprises a first end extending distally to a second end, the second end being adjacent to the distal end, the cutting lumen being formed complementary to the cutting edge.
As one advantage, the arcuate shape of the cutting edge may allow the device to contain a larger cutting edge relative to the elongate member, while the elongate member may be smaller. This allows the elongate member to maneuver within the vasculature more precisely, reducing unintended trauma.
The cutting edge may comprise a flexible material. This may be a shape memory material, such as Nitinol. The cutting edge may be controlled by an extending member being attached to the cutting edge adjacent to the proximal end. The extending member is operable to slidably move the cutting edge relative to the cutting lumen, defining an extended state and a retracted state of the cutting edge. In one embodiment, the cutting edge extends from the proximal end to the distal end.
The tension mechanism may be connected to the proximal end and extend to the cutting edge. The tension mechanism, moveable in a predetermined direction, applies a tension to the cutting edge to bend the cutting edge, defining a straight state and a bent state of the cutting edge. Through the tension mechanism and the extending member, the physician may have increased control over the cutting edge to maneuver it into and out of the subintimal space. As such, the elongate member may form a track closer to the proximal end than the distal end. The extending member may include a button slidably received in the track. The retracted state allows the physician to avoid undesirable cuts to the vessel wall.
The expandable balloon may be disposed circumferentially about the elongate member and in fluid communication with the balloon inflation lumen wherein the expandable balloon moves from a collapsed state to an expanded state to treat or ablate the occlusion. As one advantage, because the device contains the expandable balloon, this may allow the physician to have the expandable balloon and the cutting edge within the same device, to cut around and dilate the occlusion with the same device.
The elongate member comprises a plurality of side ports disposed adjacent to the distal end to provide fluid communication between the balloon inflation lumen and the expandable balloon. The expandable balloon is disposed proximal to the distal end. In one embodiment, the proximal end comprises a handle, and the tension mechanism comprises a tension core. The tension core is connected to the handle and extends distally to the cutting edge to move the cutting edge between the straight and bent states. In one embodiment, the tension core comprises a wire.
The handle being integrally formed with the elongate member at the proximal end to rotate the device. For example, rotating the handle rotates the distal end. The handle further comprises a tension lever being movable (e.g. depressible and releasable) to move the cutting edge between the straight and bent states. In another embodiment, a push member is connected to the proximal end and extends distally to the first end, the first end being disposed distal from the proximal end and extending to the distal end.
In one form, the device further comprises an L-shaped radiopaque marker at the distal end, the radiopaque marker being disposed adjacent to the cutting lumen for fluoroscopy.
The disclosure provides a method for treating an occlusion in a body vessel having a true lumen and a subintimal space, the occlusion having a first side and a second side. The method may include first, positioning a wire guide and a medical device in the true lumen adjacent to the first side, the medical device as described above; second, advancing the distal end of the elongate member from the true lumen into the subintimal space of the body vessel having the cutting edge in the extended state; third, advancing the distal end from the subintimal space into the true lumen of the body vessel and adjacent to the second side having the cutting edge in the extended state; fourth, aligning the expandable balloon with the occlusion, the expandable balloon being maintained within the subintimal space, and; fifth, ablating the occlusion.
Each step of advancing the distal end may comprise first, rotating the device about the circumference and second, applying the tension on the cutting edge to move the cutting edge from the straight state to the bent state or the bent state to the straight state. After each step of advancing the distal end, the method may comprise first, retracting the cutting edge to the retracted state and second, moving the distal end through the body vessel after the step of retracting. The step of ablating the occlusion further comprises first, inflating and second, deflating the expandable balloon.
The present disclosure generally provides a cutting edge cutting catheter suitable for treating CTO. The present disclosure also provides one example of a method for treating CTO. The disclosure provides embodiments of the medical device and the process, and the cited figures illustrate these embodiments. The accompanying figures are provided for general understanding of the structure of various embodiments. However, this disclosure may be embodied in many different forms. These figures should not be construed as limiting and they are not necessarily to scale.
All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In case of conflict, the present document and definitions will control.
“Adjacent” referred to herein is nearby, near to, or in close proximity with.
“Ablate” referred to herein is to reduce or crush a vessel occlusion.
“Adventitial layer” referred to herein is the outer surface of the blood vessel wall, farthest away from healthy blood flow.
To “bend” the cutting edge means to move the cutting edge into or toward its bent state or straight state.
“Intimal layer” referred to herein is the inner surface of the blood vessel wall, closest to healthy blood flow.
The terms “proximal” and “distal” and derivatives thereof will be understood in the frame of reference of a medical physician using the medical device; thus, proximal refers to locations closer to the physician and distal refers to locations further away from the physician (e.g. deeper in the patients vasculature).
“Subintimal space” or “subintimal layer” is area within the intimal and adventitial layers of the blood vessel walls.
“True lumen” referred to herein is the normal or healthy pathway for blood flow within the vasculature.
The elongate member 20 may comprise at least three lumens: the cutting lumen 22, the balloon inflation lumen 32, and the wire guide lumen (discussed with
In one embodiment, the cutting lumen 22 is formed in the elongate member opposite from the balloon inflation lumen 32. The wire guide lumen may be formed in the center of the elongate member 20. It is understood that the lumens may be formed in different locations of the elongate member 20 without falling beyond the scope and spirit of the present invention.
An expandable balloon 24 may be disposed circumferentially about or around the elongate member 20. In this embodiment, the expandable balloon 24 is in fluid communication with the balloon inflation lumen 32 through a plurality of side ports 30. In one aspect, three side ports are positioned proximal to the distal end 18 of the elongate member 20 to provide fluid communication between the balloon inflation lumen and the expandable balloon. It is understood that the number and position of the side ports may vary. For example, the side ports may be located at any position along the expandable balloon. In one aspect, the expandable balloon 24 is located several centimeters proximal to the distal end 18 of the elongate member 20. The expandable balloon may move from a collapsed state to an expanded state to treat the occlusion 50.
A cutting edge 26 or blade may be slidably disposed within the cutting lumen 22 and may be arcuate. The cutting edge has an arcuate cross-section, arcuately extends circumferentially up to half of the circumference. In one form, the cutting edge has a first end (discussed with
The cutting edge 26 may be manufactured by laser cutting. Further, the cutting edge 26 may be formed from any suitable material for CTO. Such material may be flexible. Further, such material may be thin to penetrate the intimal layer 54. In one embodiment, the cutting edge 26 is blunt and thin that allows it to penetrate into the subintimal space. The cutting edge 26 does not need to be sharp. The material to form the cutting edge 26 will be a thin, flexible material, such as stainless steel. In one form, the material will be a shape memory material (e.g. Nitinol).
The device also comprises a tension mechanism. The tension mechanism contains a tension core to bend the cutting edge as part of the tension mechanism. The tension core may be wire 16 which bends and straightens the cutting edge 26. Wire 16 may be connected to the proximal end and extend distally to the cutting edge. When moved in a predetermined direction, the tension mechanism applies a tension to the cutting edge to bend the cutting edge, defining a straight state and a bent state of the cutting edge. If the tension core is mechanical, it may be attached to the cutting edge through any method known in the art, such as welding, soldering, gluing or chemical bonding. A skilled artisan will understand that the tension core could also be any means known in the art to bend the cutting edge, such as a mechanical, electric, magnetic, or pneumatic mechanism.
A physician may tell which way the cutting edge faces with an L-shaped, radiopaque marker through fluoroscopy. Such a marker may be located on the side of the elongate member 20 next to or adjacent to the cutting edge 26 at the distal end. In one embodiment, when the physician views an L-shape, the cutting edge 26 is concave down. When the physician views a backwards L-shape, the cutting edge 26 is concave up.
When the physician makes a desired cut in the vasculature, the cutting edge 26 may be extended in extended state 400. When the physician desires to move the elongate member within the true lumen or within the subintimal space, the cutting edge 26 may be in retracted position 300 to avoid the risk of making an unintended cut.
As shown in
In either case, the cutting edge 26 may be further manipulated by a tension mechanism. In one embodiment the tension mechanism may be a wire (shown in
In one aspect, the push member 46 is a round wire. In another aspect, the push member is a flat wire. A skilled artisan will understand that the push member may be any shape to connect to the cutting edge without falling beyond the scope and spirit of the disclosure. In any case, the cutting lumen is formed complementary to the push wire 46 adjacent to the proximal end and formed complementary to the cutting edge 26 adjacent to the distal end. The wire may be attached to the cutting edge through any method known in the art, such as welding, soldering, gluing or chemical bonding.
Although not explicitly depicted, the body vessel has a medial layer between the adventitial layer 58 and the intimal layer 54. When the device enters the subintimal space 56, it may also penetrate into or through the medial layer.
In step 802, the physician advances the device from the first side of the occlusion 50 into the subintimal space 56, the cutting edge 26 being in the extended state. Through handle rotation and the tension mechanism, the physician positions the cutting edge 26 to cut into the subintimal space 56. This positioning may involve bending the cutting edge 26 in the direction of arrow C. In one aspect of the method, it is understood that the device may naturally line up with the intimal layer, such that there will be no need to rotate or bend the cutting edge to enter into the subintimal space 56. The cutting edge may naturally cut into the subintimal space based on its position. However, in most cases the user may need to orient the device to penetrate into the subintimal layer.
In step 804, the physician has cut into the subintimal space 56. After penetration, the physician may retract the cutting edge 26 into the retracted state and move past the occlusion 50. In step 806, the device is advanced past the occlusion 50. The physician now may desire to re-enter the true lumen 52. In this case, the user may advance the distal end from the subintimal space 56 into the true lumen 52 and adjacent to the second side of the occlusion 50 having the cutting edge being in the extended state. Again, this may involve extending the cutting edge into the extended position, rotating the device and the cutting edge 26 about the circumference in the direction of arrow D, and applying a tension on the cutting edge 26 in the direction of arrow E by way of the tension mechanism to move the cutting edge 26 between the straight state and the bent state. This same action occurs regardless of if the cutting edge is biased to be bent or straight. The physician may make the cut through the intimal layer into the true lumen 52. At this point, the physician may retract the cutting edge 26 into the retracted state after the step of advancing.
In step 808, when the device may be moved through the body vessel and advanced into the true lumen 52, the user may retract the cutting edge 26 and align the expandable balloon 24 adjacent to the occlusion 50. In one form, the expandable balloon 24 is maintained within the subintimal space 56. The user may expand the expandable balloon from the collapsed state to the expanded state to reduce or ablate the occlusion 50 against the vessel wall. Once the occlusion is pushed to the side, the user may deflate the expandable balloon, and retract the elongate member and the wire guide from the body vessel. At this point, the user has cleared the vessel's true lumen. This may allow blood flow to resume through its natural pathway.
In step 906A, the physician may retract the cutting edge to the retracted state for a first time, after the step of advancing the distal end. Likewise in step 906B, the physician may move the medical device through the vessel.
In step 910, the physician advances the distal end from the subintimal space into the true lumen of the body vessel and adjacent to the second side having the cutting edge in the extended state. Again, the physician may go through steps 906B and 908B, respectively. In step 908A, the physician may retract the cutting edge to the retracted state for a second time. In step 908B, the physician may move the device through the vessel. In step 912, the physician aligns the expandable balloon with the occlusion, the expandable balloon being maintained within the subintimal space. In step 914, the user will ablate the occlusion, by inflating and deflating the expandable balloon. At this point the occlusion has been pushed against the vessel wall and the vessel will be open for blood flow. Finally, the user withdraws the elongate member and the wire guide from the vessel.
As shown, the assembly 200 may also include a wire guide 208 configured to be percutaneously inserted within the vasculature to guide the outer sheath 204 to the occlusion. The wire guide 208 provides the outer sheath 204 with a path to follow as it is advanced within the body vessel. The size of the wire guide 208 is based on the inside diameter of the outer sheath 204 and the diameter of the target body vessel.
A needle may also be used. The needle may be used for percutaneously introducing the wire guide into the patient's body through an access site. A cutting device may also be used to expand the access site.
The elongate member 220 extends from a proximal portion 211 to a distal portion 212 and is configured for axial movement relative to the outer sheath 204 via the handle 240. Handle 240 may be integrally formed with the elongate member 220 or it may be attached to the elongate member 220 by any method known in the art. This may include gluing, bonding, welding, and the like. In this example, the distal portion 212 is shown adjacent to the distal end 218.
The outer sheath 204 further has a proximal end 216 and a hub 218 to receive the elongate member 220 advanced therethrough. The size of the outer sheath 204 is based on the size of the body vessel in which it percutaneously inserts, and the size of the elongate member 220. In this embodiment, the elongate member 220 is coaxially advanced through the outer sheath 204. In order to more easily deploy the elongate member 220 into the body vessel, it may have a lubricious coating, such as silicone or a hydrophilic polymer, e.g. AQ® Hydrophilic Coating as known in the art. Likewise, the elongate member 220 may be retracted through the outer sheath 204.
It is understood that the assembly described above is merely one example of an assembly that may be used to deploy the device in a body vessel. Of course, other apparatus, assemblies and systems may be used to deploy any embodiment of the device without falling beyond the scope or spirit of the present invention.
While the present invention has been described in terms of certain preferred embodiments it will be understood that the invention is not limited to this disclosed embodiments as those having skill in the art may make various modifications without departing from the scope of the following claims.
This application claims priority to U.S. Provisional Patent Application Ser. No. 62/033,735, filed Aug. 6, 2014, entitled “CUTTING EDGE CUTTING CATHETER,” the entire contents of which are hereby incorporated by reference.
Number | Date | Country | |
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62033735 | Aug 2014 | US |