Abstract:
An apparatus for performing a vascular treatment includes an intraluminal member that is controllingly moved during the vascular treatment. The intraluminal member of the vascular treatment device can be connected to a motor. The rotation direction of the intraluminal member can be reversed to reduce the incidence and duration of vein entanglement during a vascular ablation procedure. Reversal of direction could occur automatically, or in response to a sensor such as a load sensor provided as part of the motorized drive system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/413,895, filed on Nov. 15, 2010, the disclosure of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This specification relates to the field of vascular treatment. 
     2. Description of the Related Art 
     Sclerotherapy can be used to treat blood vessels, blood vessel malformations, and similar problems in other body systems, such as the lymphatic system, and has been used in various forms for over 150 years. In its more modern form, sclerotherapy has been used since the 1960&#39;s, in Europe, for treating various vein conditions such as; varicose veins, reticular veins, spider veins of the leg, and also some fine facial veins. 
     Sclerotherapy can be used to treat these conditions by instigating vascular fibrosis and obliteration in response to irreversible endothelial cellular destruction and exposure of the underlying subendothelial cell layer. This destruction is usually caused by the injection of a sclerosant into the vein. However, if the injected sclerosant is too weak, there may be no endothelial injury at all. If the sclerosant is a little stronger, the varicose vessel is damaged, but recanalization occurs and an incompetent pathway for retrograde blood flow persists. Finally, if the injected sclerosant is too strong, the varicose vessel endothelium is destroyed, but adjacent vessels that are not targeted for treatment may also be damaged by the sclerosant. 
     The requirement for an ideal strength of the sclerosant is complicated by the constant flow of blood through the vein that is being treated. This flow simultaneously dilutes, and thereby weakens, the sclerosant, while also transporting the sclerosant to other parts of the vascular system. 
     Thus, improved methods and devices for treating the vascular system are desired. 
     SUMMARY OF THE INVENTION 
     Some embodiments relate to a vascular treatment apparatus. The apparatus can include, for example, an elongated intraluminal member shaped and dimensioned for passage through blood vessels of a subject. The intraluminal member can include, for example, a proximal end and a distal end. The apparatus can further include a motorized drive system coupled to the intraluminal member. The motorized drive system can, in some embodiments, reverse the direction of rotation of the intraluminal member. 
     In some embodiments of the apparatus, the motorized drive system can be, for example, a reversible motor, a kinematic chain, or a gearbox. In some embodiments of the apparatus, the motorized drive system can rotationally oscillate the intraluminal member. In some embodiments, the motorized drive system can oscillate the intraluminal member in a manner configured to inhibit entanglement of the intraluminal member with the vein, or can reverse the direction of rotation when a load threshold is reached or exceeded. 
     Some embodiments relate to a method for vascular treatment. The method can include, for example, advancing an elongated intraluminal member from an access site and into the vein. The method may comprise rotating the intraluminal member or portion thereof in a first direction, and reversing the direction of rotation of the intraluminal member or portion thereof. In some embodiments of the method, the reversal of a direction of rotation occurs when a threshold load is met or exceeded. The rotation reversal can, for example, inhibit entanglement of the intraluminal member with the vein. 
     In another embodiment, a vascular treatment apparatus comprises an elongated intraluminal member shaped and dimensioned for passage through blood vessels of a subject, the intraluminal member including a proximal end and a distal end. At least a first motor is coupled to the intraluminal member to move the intraluminal member, a motor drive circuit is coupled to the motor; and a load sensor is coupled to the motor drive circuit. The motor drive circuit may stop or reverse direction of the motor in response to a sensed load. 
     In one specific application, the apparatus and methods may be applied to permanently occluding veins. In these embodiments, the intraluminal member may have a portion that can produce damage to the inner vein wall. The apparatus may further comprise a source of sclerosant and a fluid channel between the source of sclerosant and the distal end of the elongated intraluminal member. 
     The foregoing is a summary and thus contains, by necessity, simplifications, generalization, and omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is not intended to be in any way limiting. Other aspects, features, and advantages of the devices and/or processes and/or other subject matter described herein will become apparent in the teachings set forth herein. The summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an embodiment of an assembly of a vascular treatment device. 
         FIG. 2A  illustrates a longitudinal cross-sectional view of the embodiment illustrated in  FIG. 1 . 
         FIG. 2B  illustrates the distal ends of the wire and sheath of  FIG. 2A  with the distal end of the wire within the sheath. 
         FIG. 2C  illustrates the distal ends of the wire and sheath of  FIG. 2A  with the distal end of the wire extending out from the end of the sheath. 
         FIG. 3  shows a schematic view of a motion system for a vascular treatment device that incorporates a reversible motor. 
         FIG. 4  shows a schematic view of a motion system for a vascular treatment device that incorporates an oscillating gear system. 
         FIG. 5  shows a schematic view of a motion system for a vascular treatment device that incorporates a reversible motor with load sensing and additional control functions. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following description and examples illustrate preferred embodiments of the present invention in detail. Those of skill in the art will recognize that there are numerous variations and modifications of this invention that are encompassed by its scope. Accordingly, the description of a preferred embodiment should not be deemed to limit the scope of the present invention. In this description, reference is made to the drawings wherein like parts are designated with like numerals throughout. 
       FIG. 1  depicts a perspective view of one embodiment of exemplary components of a vascular treatment device  10 . These components can be configured to provide a range of functionalities to the vascular treatment device  10 . In some embodiments, a vascular treatment device  10  can include features configured for stimulating vascular ablation, such as, for example, an intraluminal member  22 , a motorized drive system, including, for example, a motor, and/or control features and/or features configured for delivering liquid sclerosant. In some embodiments described further below, the intraluminal member comprises a wire surrounded by a sheath, and the wire is rotatable within the sheath. The space between the sheath and the wire can be used as a passage to inject sclerosant as the wire rotates, and the distal end of the wire forms a vein wall disruptor. 
     In general, the vascular treatment device  10  of  FIG. 1  is utilized by introducing the intraluminal member into a vein of a subject, where the vein is to be ablated in a treatment for varicose veins for example. The distal end of the wire is extended from the distal end of the sheath, and the wire is rotated or otherwise moved to damage the endothelium lining the inside surface of the vein. Sclerosant is also injected to the region of damage through the sheath that forms an outer portion of the intraluminal member  22 . The combination of endothelium damage plus the sclerosant provides a highly effective vascular ablation procedure with a minimum amount of injected sclerosant. 
     As depicted in  FIG. 1 , a vascular treatment device can include a handle  12  and a cartridge  14 . As explained below in greater detail, each of the handle  12  and cartridge  14  can include features configured for stimulating vascular ablation and/or for delivering liquid sclerosant. In one embodiment, and as depicted in  FIG. 1 , the handle  12  and the cartridge  14  can comprise separate pieces. In another embodiment, a handle  12  and a cartridge  14  can comprise an integrated component. A person of skill in the art will recognize that the present disclosure is not limited to a specific configuration of the handle  12  and cartridge  14  but broadly includes the range of functions and uses of a vascular therapy device. 
     As further depicted in  FIG. 1 , the cartridge  14  can be, for example, sized and shaped to engagingly connect to the handle  12 . In one embodiment, and as shown in  FIG. 1 , this engaging connection can be achieved by fitting features of the handle  12  to features of the cartridge  14 . 
       FIG. 2  depicts a side cross-section view of the vascular treatment device  10  of  FIG. 1 . The vascular treatment device  10  depicted in  FIG. 2  comprises the same features discussed in relation to  FIG. 1 . Referring now to both  FIGS. 1 and 2 , the cartridge  14  may include a sheath  30  affixed to and extending from the cartridge  14 , a wire  32 , and a coupling  34 . The wire  32  can be, for example, fixed to the coupling  34 . A person of skill in the art will recognize that the wire  32  can be affixed to the coupling  34  through a variety of techniques and methods. A person of skill in the art will further recognize that the wire  32  can be affixed to a range of features of a vascular treatment device  10  configured for driving the wire  32 . 
     The wire  32  (and surrounding sheath) can comprise a variety of lengths. In some embodiments, a wire  32  can have a length matching the needs of the procedure. In some embodiments, a wire  32  can have a length, for example, of up to 10 cm, up to 25 cm, up to 75 cm, or up to 150 cm. 
     The sheath  30  can be configured to define a lumen through which the wire  32  runs, and can be configured to allow independent motion of the wire within the sheath. The sheath  30  can have a variety of inner and outer diameters. In some embodiments, the sheath  30  can have an inner diameter ranging from approximately 0.022 inches to 0.048 inches. In some embodiments, the sheath  30  can have an outer diameter ranging from approximately 0.025 inches to 0.051 inches. In some embodiments, the outer diameter of the sheath  30  can be in the range that is, for example, consistent with the inner diameter of standard needles or vascular sheaths used for used for insertion of vascular catheters. 
     The sheath  30  may also include external markings at regular intervals which may guide the user to monitor the insertion or removal speed of the intraluminal member  22 . 
     Some embodiments of a vascular treatment device  10  can be configured for use with injectant. In some embodiments, the cartridge  14  can be configured for holding an injectant such as sclerosant in a syringe  36  attached to the cartridge  14  at a coupler  28 . Some embodiments of a vascular treatment device  10  and/or a cartridge  14  configured for use in connection with an injectant can be, for example, configured with valves and connectors to facilitate such use. In some embodiments, a syringe  36  can, for example, connect to a stopcock  38  on a cartridge  14 . The stopcock  38  shown in  FIG. 2  can be configured to allow the removal and/or attachment of a syringe to the vascular treatment device  10  during a procedure. In some embodiments, a stopcock  38  can be configured to allow reloading of fluid and/or exchanging of containers to, for example, change the injectant or the concentration of the injectant. In some embodiments, the stopcock  38  can be configured to provide additional functionality, such as, for example, mixing or aerating the injectant. The output of the coupler  28  is in fluid communication with the space between the sheath  30  and the wire  32  so that the injectant can be pushed along this space to the distal end of the wire and sheath where the injectant (e.g. sclerosant) exits the sheath when installed in the vein. 
     In use, the sheath  30  with the wire  32  inside may be introduced into the vein prior to coupling the cartridge  14  to the handle  12 . At this time, the wire  32  may be fully enclosed by the sheath  30  as shown in  FIG. 2B . After introduction, the cartridge  14  can be inserted into the handle  12 , and the coupler  34  can engage a mating coupler  40  in the handle. The coupler  34  in the cartridge which is attached to the wire  32  may be slidable within the cartridge  14 , so that when the coupler  34  in the cartridge is forced into engagement with the coupler  40 , the distal end of the wire  32  is pushed out of the sheath  30 , as shown in  FIG. 2C . This exposes a portion of the wire  32  that is configured to damage the endothelium on the inner surface of the vein. The coupler  40  in the handle  12  is attached to the shaft of a motor  42  in the handle that may rotate the coupler  40 , mated coupler  34 , and attached wire  32  to scrape and damage the inner wall of the vein. During this process, sclerosant may be forced down the sheath, to exit the sheath in the region near the distal end of the wire  32 , as shown by arrows  46  in  FIG. 2C . 
     Motor rotation may be controlled by a trigger  48  in the handle that depresses and releases a switch  50  to start and stop motor rotation. The handle  12  may further include a power source for the motor such as battery  52 . Embodiments of vascular treatment devices such as illustrated in  FIGS. 1 through 2C  are further described in U.S. Pat. Nos. 7,862,575 and 7,967,834 which are incorporated herein by reference in their entireties. 
     Although vascular ablation treatments using the above described vascular treatment device have shown dramatic improvement over prior vascular ablation methods, it has been found that the drive system illustrated in  FIG. 2A  is sometimes not optimal. For example, the distal end of the wire  32  can sometimes catch on the inner vein wall, twisting the vein and entangling the wire and the vein. When this occurs, the operator of the device may need to stop the procedure to release the wire from the vein. This issue may be caused by insufficient control or variation of motor motion during the procedure, a problem that is addressed by the embodiments described below with respect to  FIGS. 3, 4, and 5 . 
       FIG. 3  illustrates one embodiment of a wire  32  drive system that helps resolve these problems. In  FIGS. 3, 4, and 5 , many components of the cartridge  14  and handle  12  are omitted for clarity, focusing only on the drive system for wire  32 . Couplers  34  and  40  are shown. In the embodiment of  FIG. 3 , a motor  50  used to drive the wire  32  is a reversible motor. The motor  50  is controlled by a motor control and driver circuit  52  that is configured to periodically change the direction of rotation of the wire  32 . Such a change in direction can be performed at defined time intervals such as one a second, ten times a second, etc., or the change in direction can be performed after a set number of rotations such as every five rotations, or with every rotation, or with fractions of a rotation if desired. Random or pseudo-random timing of rotation changes is also possible. Thus, a variety of rotational oscillation motions can be programmed or hard wired into the motor control and driver circuit  52 . Such motors and motor control circuits are well known and commercially available, and can be used in place of the motor  42  and single direction rotation of  FIG. 2 . With these direction rotations, entanglement with the vein is less likely, and if it does occur, the next direction reversal is likely to free the wire from the vein. 
       FIG. 4  depicts a motorized drive system comprising a trigger  48 , a motor driver circuit  54 , a motor  56 , and a kinematic chain  58  connecting the motor  56  to the coupler  40 . The kinematic chain  58  can comprise, for example, an assemblage of links and joints interconnected so as to provide a desired output in response to desired input. In some embodiments, the kinematic chain  58  can comprise one or several gears, one or several rigid linked members, one or several flexible linked members, or any other desired feature. In some embodiments, the kinematic chain  58  can be configured to translate a single direction motor  56  output into rotational oscillation of the wire  32 . 
       FIG. 4  depicts one specific kinematic chain  58  comprising a first wheel  60 , a link  62 , and a second wheel  64 . In some embodiments, the motor  56  can rotate the first wheel  60  about the axis of the motor driven shaft. A first end of the link  62  can be rotationally connected to a portion of the first wheel  60 , and a second end of the link  62  can be rotationally and slidingly connected with a portion of the second wheel  64 . The combination of the rotational connection of the first end of the link  62  to the first wheel  60 , and the rotational and sliding connection of the second end of the link  62  to the second wheel  64  can allow conversion of the single direction rotational input of the driven shaft of the motor to rotationally oscillating output of the motorized drive system output. Although one specific kinematic chain  58  is described herein, a person of skill in the art will recognize that a variety of kinematic chains can be used in connection with the motorized drive system to achieve the desired movement of the wire  32 . The motorized drive system of  FIG. 4  utilizes a simpler and less expensive motor and motor drive circuit compared to the system of  FIG. 3 , with the addition of the mechanical components of the kinematic chain  58 . 
       FIG. 5  depicts a motorized drive system comprising a trigger  48 , a motor control and driver circuit  72 , and a reversible motor  70 . In addition to these features,  FIG. 5  depicts a load sensor  76  that may be incorporated into the motor control and driver circuit  72 . The load sensor  76  can be configured to detect the motor load based on inputs from an output current sensor  74  that senses the current being used to drive the motor and/or other sensor signals such as speed and torque signals that may be routed to the motor control and drive circuit  72  from sensors integral to the motor  70 . For example, the load sensor may determine that the current to the motor has exceeded a threshold, that the torque output has exceeded a threshold, or that the speed of rotation has slowed below a threshold. It will be appreciated that the load sensor,  76 , current sensor  74  or other motor parameter sensors can be incorporated into the motor  70 , the motor control and driver circuit  72 , be standalone components, or have portions thereof distributed in any of these or other locations. The load sensor  76  can comprise software, hardware, or a combination of hardware and software. 
     The motor control and driver circuit  72  can be configured to control the motor based in part on signals generated by the motor load sensor  76 . In some embodiments, the motor control and driver circuit  72  may speed up the rotation rate of the motor  70 , slow down the rotation rate of the motor  70 , or reverse the direction of rotation of the motor  70  in response to signals generated by the motor load sensor  76 . In one embodiment, the motor control and driver circuit  72  can be configured to reverse the direction of rotation of the motor  72  when the motor load sensor  76  detects a motor load which meets or exceeds a load threshold. In some embodiments, this load threshold can, for example, correspond to a condition with the treated vessel, such as, for example, entanglement of the wire  32  in vein tissue, over penetration of the wire  32  into vein tissue, or other conditions. Advantageously, the reversing of the direction of rotation of the motor  70 , and thereby reversing the direction of rotation of the wire  32  can minimize the severity and duration of, and/or prevent entanglement of the wire  32  with the vein. 
     In some embodiments, the motor control and driver circuit  72  is user programmable with a variety of motor control options. The user may, for example, be able to select a rotation speed, a desired torque value or torque limit during the procedure, the direction of rotation, and whether and how quickly the wire should oscillate back and forth with reversing rotations or rotate in one direction only. The motorized drive system can, for example, be programmable to rotate the wire  32  at any rate between approximately 500 to 5,000 rpm, and reverse direction at any rate between every half rotation to every 500 rotations. 
     The device could include switches or a keypad for such programmable control, or may have an input/output port for interfacing to a computer for download of configuration choices. The behavior of the motor control and driver circuit  72  in response to sensor inputs related to load, speed, etc. could also be programmable, or may be fixed at manufacture. 
     The foregoing description details certain embodiments of the devices and methods disclosed herein. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the devices and methods can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the technology with which that terminology is associated. Furthermore, although the above description has focused on the application of the principles discussed to vein ablation procedures, the features set forth above could be applied to a variety of vascular treatments. 
     It will be appreciated by those skilled in the art that various modifications and changes may be made without departing from the scope of the described technology. Such modifications and changes are intended to fall within the scope of the embodiments. It will also be appreciated by those of skill in the art that parts included in one embodiment are interchangeable with other embodiments; one or more parts from a depicted embodiment can be included with other depicted embodiments in any combination. For example, any of the various components described herein and/or depicted in the Figures may be combined, interchanged or excluded from other embodiments. 
     With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. 
     It will be understood by those within the art that, in general, terms used herein are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” 
     All references cited herein are incorporated herein by reference in their entirety. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material. 
     The term “comprising” as used herein is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.