Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS20070255270 A1
Publication typeApplication
Application numberUS 11/412,767
Publication date1 Nov 2007
Filing date27 Apr 2006
Priority date27 Apr 2006
Also published asUS7854740, US20090192405, WO2007127530A1
Publication number11412767, 412767, US 2007/0255270 A1, US 2007/255270 A1, US 20070255270 A1, US 20070255270A1, US 2007255270 A1, US 2007255270A1, US-A1-20070255270, US-A1-2007255270, US2007/0255270A1, US2007/255270A1, US20070255270 A1, US20070255270A1, US2007255270 A1, US2007255270A1
InventorsAlan Carney
Original AssigneeMedtronic Vascular, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Intraluminal guidance system using bioelectric impedance
US 20070255270 A1
Abstract
A system using bioelectric impedance to guide a flexible elongate transluminal device through an occlusion in a vessel. The device can be a guidewire or a device for performing an atherectomy, discectomy, ablation or similar technique. The device includes a first electrode disposed on a distal portion of the device. A second electrode is disposed in electric contact with the patient separate from the first electrode. An electric current is supplied between the first and second electrodes and a voltage drop is measured between the first and second electrodes. The voltage drop is converted to bioelectric impedance. Based on the impedance measurement, a clinician can determine if the device is approaching the vessel wall, permitting the clinician to redirect the device away from the vessel wall.
Images(5)
Previous page
Next page
Claims(25)
1. A guidance system for crossing an occlusion in a patient's vessel, the system comprising:
a first flexible elongate element adapted for transluminally approaching and crossing the occlusion, the first elongate element having a first electrode disposed adjacent a distal end thereof, the first electrode electrically connectable to the patient;
a second electrode electrically connectable to the patient, wherein the second electrode is a skin electrode or the second electrode is disposed on a balloon, the balloon mounted on a flexible elongate catheter adapted for transluminal insertion into the vessel;
an electric power source connectable to the first and second electrodes and adapted to provide an electric current thereto; and
an impedance monitor connectable to the first and second electrodes and adapted to determine a bioelectric impedance there between.
2-4. (canceled)
5. The system of claim 1, wherein the first elongate element is a guidewire
6. The system of claim 1, wherein the first elongate element is an ablation device.
7. The system of claim 6, wherein the power source provides power to the ablation device.
8. The system oft claim 7, wherein the impedance monitor is coupled to a shut-off switch that shuts off power to the ablation device when the impedance drops below a predetermined value.
9. The system of claim 1, wherein the current provided by, the power source is an alternating current with a frequency in the range of 1 kHz to 500 kHz.
10. The system of claim 1, wherein the impedance monitor is coupled to an alarm that sounds when the impedance drops below, a predetermined value.
11. The system oft claim 1, wherein the first elongate element is an atherectomy device comprising a rotatable cutting head wherein the first electrode is disposed on the cutting head.
12. The system of claim 11, wherein the impedance monitor is coupled to a shut-off switch that stops the cutting head frown rotating when the impedance drops below a predetermined value.
13. The system of claim 1, wherein the first elongate element is an atherectomy device comprising a rotatable cutting head, further comprising a guidewire disposed within the cutting head, wherein tire first electrode is disposed on the guidewire.
14. A method for guiding a device through an occlusion in a patient's vessel, the method comprising the steps of:
delivering a flexible elongate element transluminally to the occlusion, wherein a first electrode is disposed on a distal portion of the elongate element;
advancing the elongate element into the occlusion;
providing a second electrode separate from the first electrode and in electrical contact with the patient, wherein the second electrode is a skin electrode or the second electrode is disposed on a balloon, the balloon mounted on a flexible elongate catheter adapted for transluminal insertion into the vessel;
providing an electric power source coupled to the first and second electrodes;
activating the power source to provide an electric current between the first and second electrodes;
measuring a voltage drop between the first and second electrodes; and
calculating a bioelectric impedance based on the voltage drop between the first and second electrodes.
15-17. (canceled)
18. The method of claim 14, wherein the step of activating the power source to provide a current between the first and second electrodes takes place in a pulsed sequence.
19. The method of claim 18, wherein the impedance is calculated each time a current is provided between the first and second electrodes.
20. The method of claim 14, further comprising the step of advancing the elongate element through the occlusion as the current is applied between the first and second electrodes.
21. The method of claim 14, further comprising, prior to advancing the elongate element into the occlusion, the steps of:
positioning the first electrode in electrical contact with the vessel adjacent the occlusion;
measuring a voltage drop between the first electrode and the second electrode; and
calculating a predetermined bioelectric impedance value based on the voltage drop between the first second electrodes.
22. The method of claim 14, further comprising the step of directing the elongate element away from the vessel wall when the calculated impedance reaches a predetermined bioelectric impedance value.
23. The method of claim 14, wherein an alarm is triggered when the calculated impedance reaches a predetermined bioelectric impedance value.
24. The method of claim 14, wherein the elongate element is a guidewire.
25. The method of claim 14, wherein the elongate element is an atherectomy device.
26. The method of claim 25, wherein the atherectomy device includes a cutting head that rotates as the atherectomy device is advanced through the occlusion.
27. The method of claim 26, wherein a shut-off switch stops the rotation of the cutting head when the impedance reaches a predetermined level.
28. The method of claim 14, wherein the elongate element is a laser ablation device.
29. The method of claim 23, wherein the power source provides power to the laser ablation device, and wherein a shut-off switch off power to the laser ablation device when the impedance reaches a predetermined level.
Description
    FIELD OF THE INVENTION
  • [0001]
    The disclosure relates generally to a guidance system for use in a patient's vessel, and more particularly, to a system for guiding an intra-luminal device through an arterial chronic total occlusion (CTO) using bioelectric impedance.
  • BACKGROUND OF THE INVENTION
  • [0002]
    Stenotic lesions may comprise a hard, calcified substance and/or a softer thrombus material, each of which forms on the lumen walls of a blood vessel and restricts blood flow there through. Intra-luminal treatments, such as balloon angioplasty, stent deployment, atherectomy, and thrombectomy are well known and have proven effective in the treatment of such stenotic lesions. These treatments often involve the insertion of a therapy catheter into a patient's vasculature, which may be torturous and may have numerous stenoses of varying degrees throughout its length. In order to place the distal, treatment portion of a catheter within the treatment site, a steerable guidewire is typically introduced and tracked from an incision, through the vessels, and across the lesion. Then, a catheter, e.g., a balloon catheter, perhaps carrying a stent, can be tracked over the guidewire to the treatment site. Ordinarily, the distal end of the guidewire is quite flexible so that as it is directed, or steered through the lumen, it can find its way through the turns of the typically irregular passageway without perforating or otherwise damaging the vessel wall.
  • [0003]
    In some instances, the extent of occlusion of the lumen is so severe that the lumen is completely or nearly completely obstructed, leaving virtually no passageway for the guidewire. Such a condition may be described as a total occlusion. If this occlusion persists for a long period of time, the lesion is referred to as a chronic total occlusion or CTO. Furthermore, in the case of diseased blood vessels, the lining of the vessels may be characterized by the prevalence of atheromatous plaque, which may form total occlusions. The extensive plaque formation of a chronic total occlusion typically has a fibrous cap surrounding softer plaque material. This fibrous cap may present a surface that is difficult to penetrate with a conventional guidewire, and the typically flexible distal tip of the guidewire may be unable to cross the lesion.
  • [0004]
    Thus, for treatment of total occlusions, guidewire having stiffer distal tips have been employed to recanalize a total occlusion. However, blood vessels are not straight and fluoroscopic visualization of the natural path through an occlusion is poor because there is little or no flow of radiographic contrast through the occlusion. Therefore, simply using a stiffer guidewire to push through an occlusion increases the risk that the guidewire tip will penetrate the vessel wall.
  • [0005]
    Atherectomy is another established treatment for occlusions. Atherectomy procedures typically involve inserting a cutting or ablating device through the access artery, e.g. the femoral artery or the radial artery, and advancing it through the vascular system to the occluded region, and rotating the device at high speed via a drive shaft to cut through or ablate the plaque over the wire. The removed plaque or material can then be suctioned out of the vessel or be of such fine diameter that it is cleared by the reticuloendothelial system. Atherectomy devices also present the danger of unwanted perforation of a vessel wall by the material removal device. This can occur when the material removal device improperly engages the vessel wall, for example when the material removal device is not oriented substantially parallel to the axis of the vessel. In this situation, the material removal device, e.g. cutter or abrasive ablator, may improperly engage the vessel wall and cause unwanted damage thereto. Other ablation and discectomy devices also present the danger of damage to a vessel wall.
  • [0006]
    Thus, there is a need for a device and method to reduce the risk of damage to a vessel wall when a guidewire or a device for performing an atherectomy, discectomy, ablation or similar procedure is crossing an occlusion.
  • [0007]
    Electrical impedance is the opposition to the flow of an alternating current, which is the vector sum of ohmic resistance plus additional resistance, if any, due to induction, to capacitance, or to both. Bioelectric impedance is known, e.g., for use in measuring body fat composition. For example, bathroom scales may include means to measure body fat composition using bioelectric impedance. According to this technique, a person's body fat is measured by determining the impedance of the person's body to electrical signals, and calculating the percent body fat based upon the measured impedance and other variables, such as height, weight, age, and sex.
  • [0008]
    Bioelectric impedance is typically determined by supplying a harmless electric current through at least two separated electrodes that contact portions of a body, and measuring a voltage across the body portion. This voltage is measured either (1) via the same electrodes through which current is supplied, or (2) via one or more distinct pairs of voltage-measuring electrodes. The bioelectric impedance is then readily calculated from the current and the measured voltage. The calculated bioelectric impedance may be compared to an expected value or range of common or known values, or it may be compared to one or more bioelectric impedance values previously measured in, and calculated for the same patient.
  • BRIEF SUMMARY OF THE INVENTION
  • [0009]
    The present disclosure is a system that uses bioelectric impedance to guide an elongate intraluminal device through an occlusion in a vessel. The device can be a medical guidewire or a therapeutic catheter for performing an angioplasty, atherectomy, discectomy, ablation or similar procedure. The device includes an electrode disposed on a distal portion of the device. A second electrode is disposed separately of the first electrode, either on the same device or on a separate device. For example, the second electrode may be mounted on a skin electrode or on a balloon of a catheter. The system provides an electric power source and an impedance monitor for connection to the first and second electrodes.
  • [0010]
    During use of the above system to guide an elongate device through a vessel occlusion in a patient, a first electrode is disposed adjacent the occlusion targeted for crossing. A second electrode is spaced apart from the first electrode and disposed in electrical contact with the patient's tissue, e.g., against the wall of the occluded or another vessel. The second electrode may be a skin electrode in contact with the patient's skin. As the elongate device is advanced through the occlusion, an electric current is supplied between the first and second electrodes and a voltage drop is measured between the first and second electrodes. The voltage drop is converted arithmetically to a calculated bioelectric impedance. By comparing the measured/calculated bioelectric impedance to a known, e.g., expected standard or previously measured impedance, a clinician can determine whether the device is approaching the vessel wall and posing a risk of perforating the wall. With this information, the clinician can halt advancement of the device, and possibly redirect the device away from the vessel wall.
  • BRIEF DESCRIPTION OF DRAWINGS
  • [0011]
    The foregoing and other features and advantages of the disclosure will be apparent from the following description of the disclosure as illustrated in the accompanying drawings. The accompanying drawings, which are incorporated herein and form a part of the specification, further serve to explain the principles of the disclosure and to enable a person skilled in the pertinent art to make and use the disclosure. The drawings are not to scale.
  • [0012]
    FIG. 1 is a partial cut-away view of a vessel including an occlusion and illustrating a system in accordance with an embodiment of the present disclosure.
  • [0013]
    FIG. 2 illustrates the system as shown in FIG. 1, with the introduction of a microcatheter.
  • [0014]
    FIG. 3 illustrates the system as shown in FIG. 2, with the introduction of a guidewire.
  • [0015]
    FIG. 4 illustrates the system as shown in FIG. 3, with the guidewire advanced into the occlusion.
  • [0016]
    FIG. 5 is a partial cut-away view of the system of FIGS. 1-4 illustrating a schematic representation of equipment outside of the vessel.
  • [0017]
    FIG. 6 is a side view of a steerable guidewire of the present disclosure.
  • [0018]
    FIG. 7 is a partial cut-away view of a vessel including an occlusion and illustrating another embodiment in accordance with the present disclosure.
  • [0019]
    FIG. 8 is a cross-section of a vessel including an occlusion and showing another embodiment in accordance with the present disclosure.
  • [0020]
    FIG. 9 is a plan view of a patient illustrating another embodiment in accordance with the present disclosure.
  • DETAILED DESCRIPTION OF THE INVENTION
  • [0021]
    Specific embodiments of the present disclosure are now described with reference to the figures, where like reference numbers indicate identical or functionally similar elements. The terms “distal” and “proximal” are used in the following description with respect to a position or direction relative to the treating clinician. “Distal” or “distally” are a position distant from or in a direction away from the clinician. “Proximal” and “proximally” are a position near or in a direction toward the clinician.
  • [0022]
    The present disclosure is directed to a system and method for guiding an elongate medical device, such as a guidewire or catheter for performing an angioplasty, atherectomy, dissection, or ablation, through an occlusion in a patient's vessel. Although the present description relates to crossing an occlusion in a blood vessel, such as an arterial stenosis, the invention is not so limited, and may be applicable for providing guidance during crossing of other blockages in other passageways in a patient. A blood vessel 10 with an occlusion 12 blocking blood flow through it is shown in FIGS. 1-4. A balloon catheter 14 with a balloon 16 near its distal end is advanced through the vasculature to a position proximal to occlusion 12, as shown in FIG. 1. Catheter 14 and balloon 16 can be made of materials known to those skilled in the art. In an embodiment of the present disclosure, balloon 16 includes a second, ring electrode 18 disposed about its periphery. Optionally, a micro-catheter 20 is advanced through catheter 14 such that a distal portion of micro-catheter 20 extends from a distal end of catheter 14, as shown in FIGS. 2 and 3. A guidewire 22 may be advanced through balloon catheter 14 and optional micro-catheter 20 and extends into occlusion 12, as shown in FIGS. 3 and 4. Although FIG. 1 shows balloon 16 inflated for clarity of the illustration, balloon 16 is typically advanced through blood vessel 10 in an uninflated condition. Balloon 16 is inflated prior to advancing guidewire through occlusion 12. Thus, balloon 16 need not be inflated until after the step shown in FIG. 3, although it can be inflated at anytime after being advanced through blood vessel 10 to the position shown in FIG. 1. Further, although FIGS. 1-4 show balloon 16 with ring electrode 18, any suitable device can be equipped with an electrode, provided that the electrode can be maintained in electrical contact with the wall of the vessel during crossing of the occlusion. For example, a second guidewire could be used with an electrode disposed thereon and placed against the wall of the vessel. Alternatively, the second electrode may be positionable in electrical contact with the patient's tissue in a different vessel, or outside of the patient's vascular system, or outside the patient's body, viz. a skin electrode as will be discussed below with respect to electrode 50.
  • [0023]
    Referring to FIG. 6, guidewire 22 includes a tip 24 with a first electrode 26 disposed thereon. Guidewire 22 in FIG. 6 is shown as a steerable guidewire. Any guidewire suitable for crossing an occlusion may be used, as would be apparent to those skilled in the art. Guidewire 22 can be fabricated from materials as known to those skilled in the art. Electrode 26 may be an electrically conducting electrode and can be fabricated from a variety of conductive materials known in the art, including stainless steel, copper, silver, gold, platinum and alloys and combinations thereof.
  • [0024]
    Referring to FIG. 5, an electrically conductive lead 28 communicates with electrode 26, as by an insulated wire (not shown) within guidewire 22, and lead 28 extends outside of the body to an electric power source 32. An electrically conductive lead 30 communicates with ring electrode 18, as by an insulated or otherwise electrically isolated wire (not shown) within catheter 14, and lead 30 extends outside the body to an electrical impedance monitor 34. Power source 32 and impedance monitor 34 are connected together externally or they may be combined in an integral device. Power source 32 and impedance monitor 34, in conjunction with leads 28, 30 and electrodes 18, 26 form a complete electrical circuit that includes a portion of a patient's body extending between electrodes 18, 26. The materials that define the portion of a patient's body in the electrical circuit will be discussed in detail below.
  • [0025]
    Power source 32 generates a harmless electric current through lead 28 between electrodes 26 and 30. The current may be a pulsed and/or alternating current and the selected alternating frequency may be in the range of 1 kHz to 500 kHz or other suitable frequencies known to those of skill in the art of bioelectric impedance. Ring electrode 18 may be fabricated from a variety of conductive materials known in the art, including stainless steel, copper, silver, gold, platinum and alloys and combinations thereof. In an alternative embodiment of the disclosure, a smaller, viz., non-ring shaped electrode or a plurality of electrodes may be disposed on balloon 16, provided such that that the electrode(s) may be brought into electrical contact with the wall of vessel 10, as by inflating balloon 16 into apposition with the vessel wall.
  • [0026]
    In practice, as guidewire 22 is advanced through occlusion 12, power source 32 generates an electric current through leads 28, 30 and through the patient's tissue between electrodes 18, 26. The current can be pulsed in a suitable range of pulse frequencies as may be determined by those of skill in the art of bioelectric impedance. While current is flowing through electrodes 18, 26, a corresponding resistance or voltage drop is measured between electrodes 18, 26. The voltage drop is arithmetically converted to an impedance measurement at impedance monitor 34. Impedance monitor 34 may include logic resources, such as a microprocessor, and/or memory resources, such as a RAM or DRAM chip, configured to analyze, store and display bioelectric information derived from electrodes 18, 26. For example, impedance monitor 34 may include a voltage-current converting circuit, an amplifying circuit, an A/D converting circuit, and an impedance arithmetic operation section. Impedance monitor 34 may further include, or may be coupled to, a display device 34 d, such as a cathode ray tube, liquid crystal display, plasma display, flat panel display or the like.
  • [0027]
    Occlusions 14 are generally made of atherosclerotic plaques. Although atherosclerotic plaques may vary, they contain many cells; mostly these are derived from cells of the wall that have divided wildly and have grown into the surface layer of the blood vessel, creating a mass lesion. Plaques also contain cholesterol and cholesterol esters, commonly referred to as fat, that lie freely in the space between the cells and within the cells themselves. A large amount of collagen is present in the plaques, particularly in advanced plaques of the type which cause clinical problems. Additionally, human plaques contain calcium to varying degrees, hemorrhagic material including clot and grumous material composed of dead cells, fat and other debris. Plaques also contain about 10-20% water. This general composition of atherosclerotic plaques results in a relatively high electrical resistance (and correspondingly high bioelectric impedance), as compared to more lean body tissue, such as vessel wall 10.
  • [0028]
    Thus, when electrode 26 located on tip 24 of guidewire 22 is disposed generally at the center of occlusion 12, the electric current from power source 32 passes through the relatively high resistance atherosclerotic plaque of occlusion 12 before reaching the relatively lower resistance wall of vessel 10. The current then travels through the wall of vessel 10 to ring electrode 18. If tip 24 of guidewire 22 goes off-course such that it becomes closer to the wall of vessel 10, then the current travels a shorter distance through less thickness of the relatively high resistance atherosclerotic plaque of occlusion 12 before reaching the wall of vessel 10. Ultimately, if tip 24 approaches the wall of vessel 10, the current passes through very little of the relatively high resistance atherosclerotic plaque of occlusion 12 before reaching vessel 10. Thus, the impedance detected between electrodes 18, 26 and displayed at impedance monitor 34 will decrease if tip 24 approaches the wall of vessel 10.
  • [0029]
    A clinician may stop the advancement of, and/or attempt to redirect guidewire 22 away from the wall of vessel 10 when the bioelectric impedance drops below a certain threshold value. Such a threshold value may be measured and calculated by measuring bioelectric impedance in undiseased vessel tissue adjacent target occlusion 12, using the system of the disclosure prior to advancing guidewire 22 into occlusion 12. Alternatively, a bioelectric impedance threshold value for comparison during crossing of occlusion 12 may be a value that may be predicted by an experienced clinician, or a value that a large number of similar patients are known to have in common, or a value that is otherwise available, e.g., from a printed or electronic reference source. The clinician's reaction to the bioelectric impedance reaching a low limit may prevent tip 24 of guidewire 22 from piercing vessel 10. Impedance monitor 34 may further include an alarm 34 a such that when the impedance reaches a predetermined limit, the alarm is activated, thereby alerting the clinician that the impedance has reached the predetermined limit.
  • [0030]
    FIG. 7 shows another embodiment of the present disclosure which is similar to the embodiment shown in FIGS. 1-6 except that an atherectomy device 36 is advanced through balloon catheter 14 into occlusion 12. Atherectomy device 36 includes a cutting head 38 that is rotated at high speed, e.g., via a drive shaft to cut or ablate a passageway through the plaque of occlusion 12. The removed plaque or material may be suctioned out of the vessel as is known to those skilled in the art. A first electrode 44 is disposed on cutting head 38. An electric current is provided through electrodes 18, 44 and a voltage drop is measured between electrodes 18, 44, in the same manner as described above with respect to the embodiment of FIGS. 1-6 (the power source, impedance monitor, and leads are not shown). The measured voltage drop is converted to impedance by the impedance monitor. Based on the calculated impedance, it can be determined if cutting head 38 is too close to the wall of vessel 10. In such a case, advancement of atherectomy device 36 may be halted and/or cutting head 38 may be redirected away from the wall of vessel 10. In any of the embodiments wherein the device for crossing occlusion 12 is power-assisted, impedance monitor 34 may further include a shut-off switch 34 s such that when the impedance reaches a predetermined low limit, power to the device is shut-off. For example, power to atherectomy device 36 may be shut-off by switch 34 s such that cutting head 38 stops rotating, thereby preventing cutting head 38 from damaging vessel 10.
  • [0031]
    FIG. 8 is an alternative embodiment of atherectomy device 36 shown in FIG. 7. An atherectomy device 36 a of FIG. 8 includes a guidewire 40 disposed through and extending slightly beyond a cutting head 38 a. A first electrode 42 is disposed at the distal tip of guidewire 40. Atherectomy device 36 a functions in the same manner as the device of FIG. 7, except that the electrode is disposed in a different position.
  • [0032]
    In an alternative to the embodiments described with respect to FIGS. 1-8, balloon 16 with ring electrode 18 is not required. Instead, a second, skin electrode 50 may be placed externally on the patient's chest, as shown in FIG. 9. In this embodiment, if one of first electrodes 26, 42 or 44 is in occlusion 12, not near the wall of vessel 10, then the impedance between first electrodes 26, 42 or 44 and skin electrode 50 may be safely above the bioelectric impedance threshold low limit and the clinician can continue advancing guidewire 22, atherectomy device 36, 36 a, or a device for performing laser ablation, discectomy, or other similar procedures. When guidewire 22, atherectomy device 36, 36 a, or a device for performing laser ablation, discectomy, or other similar procedures approaches the wall of vessel 10, the impedance between first electrodes 26, 42 or 44 and skin electrode 50 may approach the bioelectric impedance threshold low limit, and optionally providing an audible or visual signal to the clinician. When a signal is detected, the clinician may be alerted, for example, by impedance monitor 34, to indicate that the device crossing occlusion 12 may need to be redirected away from the wall of vessel 10. Upon examination, the clinician may determine that the device has safely passed through occlusion 12 and electrode 26, 42, or 44 may have contacted the wall of vessel 10 distal to occlusion 12.
  • [0033]
    Impedance monitor 34 may include display device 34 d, alarm 34 a, and shut-off switch 34 s, as described with respect to the embodiment shown in FIG. 5. While the embodiment with skin electrode 50 is described in conjunction with the detection of any bioelectric impedance value indicating to the clinician that the device may be approaching the vessel wall, the embodiments may be interchangeable. For example, when using ring electrode 18 on balloon 16, a low value of impedance may not be detected between electrode 26, 42, or 44 and ring electrode 18 when guidewire 22 is near the center of occlusion 12. Factors such as the frequency of the current provided by power source 32 and the location of ring electrode 18, for example, may be adjusted so that the device functions in the “go/no-go” manner. Similarly, skin electrode 50 may be used in the embodiments described in FIGS. 1-8 such that changes in the measured bioelectric impedance may apprise the clinician of the anatomical location of the device in the patient, instead of providing information regarding the distance of the device from a surrounding vessel wall.
  • [0034]
    While various embodiments of the present disclosure have been described above, it should be understood that they have been presented by way of illustration and example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the disclosure. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the appended claims and their equivalents. It will also be understood that each feature of each embodiment discussed herein, and of each reference cited herein, can be used in combination with the features of any other embodiment. All patents and publications discussed herein are incorporated by reference herein in their entirety.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US5443470 *14 Apr 199322 Aug 1995Vesta Medical, Inc.Method and apparatus for endometrial ablation
US6095987 *19 Sep 19971 Aug 2000Imagyn Medical Techonologies California, Inc.Apparatus and methods of bioelectrical impedance analysis of blood flow
US6416523 *3 Oct 20009 Jul 2002Scimed Life Systems, Inc.Method and apparatus for creating channels through vascular total occlusions
US6478769 *22 Feb 200012 Nov 2002The Board Of Trustees Of The University Of ArkansasAnatomical fluid evacuation apparatus and method
US6496725 *28 Dec 200017 Dec 2002Tanita CorporationApparatus for determining degree of restoration of diseased part
US6565588 *28 Nov 200020 May 2003Pathway Medical Technologies, Inc.Intralumenal material removal using an expandable cutting device
US6620139 *11 Nov 199916 Sep 2003Tre Esse Progettazione Biomedica S.R.L.Catheter system for performing intramyocardiac therapeutic treatment
US6824550 *22 Aug 200030 Nov 2004Norbon Medical, Inc.Guidewire for crossing occlusions or stenosis
US6962587 *25 Jul 20018 Nov 2005Rita Medical Systems, Inc.Method for detecting and treating tumors using localized impedance measurement
US6980853 *21 Feb 200327 Dec 2005Tanita CorporationDeep-vein thrombosis determination apparatus
US20020016624 *14 Feb 20017 Feb 2002Prolific Medical, Inc.Apparatus and method for controlled removal of stenotic material from stents
US20020046756 *14 Sep 200125 Apr 2002Laizzo Paul A.System and method for determining tissue contact of an implantable medical device within a body
US20030109871 *25 Jul 200112 Jun 2003Johnson Theodore C.Apparatus for detecting and treating tumors using locaIized impedance measurement
US20030139763 *14 Mar 200324 Jul 2003Duerig Thomas W.Total occlusion guidewire device
US20040167412 *13 Jan 200426 Aug 2004Tanita CorporationVenous distensibility evaluation index measuring apparatus
US20060064038 *10 Feb 200423 Mar 2006Nihon UniversityDevice for measuring elastic characteristics of organism tissue
US20060085049 *19 Oct 200520 Apr 2006Nervonix, Inc.Active electrode, bio-impedance based, tissue discrimination system and methods of use
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US848919214 Jun 201216 Jul 2013Holaira, Inc.System and method for bronchial dilation
US856004220 Mar 201215 Oct 2013Medtronic, Inc.Locating an indicator
US866064014 Apr 200925 Feb 2014Medtronic, Inc.Determining a size of a representation of a tracked member
US870013318 Jun 201215 Apr 2014Smart Iv LlcApparatus and method for monitoring catheter insertion
US87316417 May 201220 May 2014Medtronic Navigation, Inc.Combination of electromagnetic and electropotential localization
US873167218 Jun 201320 May 2014Holaira, Inc.System and method for bronchial dilation
US874089528 Jun 20133 Jun 2014Holaira, Inc.Delivery devices with coolable energy emitting assemblies
US876843414 Apr 20091 Jul 2014Medtronic, Inc.Determining and illustrating a structure
US877794328 Jun 201315 Jul 2014Holaira, Inc.Delivery devices with coolable energy emitting assemblies
US880169327 Oct 201112 Aug 2014C. R. Bard, Inc.Bioimpedance-assisted placement of a medical device
US880828020 Apr 201219 Aug 2014Holaira, Inc.Systems, assemblies, and methods for treating a bronchial tree
US882148920 Apr 20122 Sep 2014Holaira, Inc.Systems, assemblies, and methods for treating a bronchial tree
US883170114 Apr 20099 Sep 2014Medtronic, Inc.Uni-polar and bi-polar switchable tracking system between
US88397989 Apr 200923 Sep 2014Medtronic, Inc.System and method for determining sheath location
US884318914 Apr 200923 Sep 2014Medtronic, Inc.Interference blocking and frequency selection
US8887736 *15 Apr 200918 Nov 2014Medtronic, Inc.Tracking a guide member
US891143911 Nov 201016 Dec 2014Holaira, Inc.Non-invasive and minimally invasive denervation methods and systems for performing the same
US893228926 Sep 201113 Jan 2015Holaira, Inc.Delivery devices with coolable energy emitting assemblies
US896150720 Apr 201224 Feb 2015Holaira, Inc.Systems, assemblies, and methods for treating a bronchial tree
US896150820 Apr 201224 Feb 2015Holaira, Inc.Systems, assemblies, and methods for treating a bronchial tree
US900519526 Sep 201114 Apr 2015Holaira, Inc.Delivery devices with coolable energy emitting assemblies
US901732428 Jun 201328 Apr 2015Holaira, Inc.Delivery devices with coolable energy emitting assemblies
US910128512 Jun 201311 Aug 2015Medtronic, Inc.Reference structure for a tracking system
US912564330 Apr 20148 Sep 2015Holaira, Inc.System and method for bronchial dilation
US91318728 Mar 201215 Sep 2015Medtronic, Inc.Multiple sensor input for structure identification
US914932811 Nov 20106 Oct 2015Holaira, Inc.Systems, apparatuses, and methods for treating tissue and controlling stenosis
US917986014 Apr 200910 Nov 2015Medtronic, Inc.Determining a location of a member
US92654435 May 201423 Feb 2016Bard Access Systems, Inc.Method of locating the tip of a central venous catheter
US933292814 Apr 200910 May 2016Medtronic, Inc.Method and apparatus to synchronize a location determination in a structure with a characteristic of the structure
US933920614 Jun 201017 May 2016Bard Access Systems, Inc.Adaptor for endovascular electrocardiography
US93396185 Nov 201217 May 2016Holaira, Inc.Method and apparatus for controlling narrowing of at least one airway
US93454223 Oct 201424 May 2016Bard Acess Systems, Inc.Method of locating the tip of a central venous catheter
US939893327 Dec 201326 Jul 2016Holaira, Inc.Methods for improving drug efficacy including a combination of drug administration and nerve modulation
US941518831 Jul 201416 Aug 2016C. R. Bard, Inc.Bioimpedance-assisted placement of a medical device
US943342815 Oct 20146 Sep 2016Shockwave Medical, Inc.Low profile electrodes for an angioplasty shock wave catheter
US944573410 Aug 201020 Sep 2016Bard Access Systems, Inc.Devices and methods for endovascular electrography
US944574326 Aug 201320 Sep 20163Dt Holdings, LlcMethods for generating luminal organ profiles using impedance
US945676627 May 20114 Oct 2016C. R. Bard, Inc.Apparatus for use with needle insertion guidance system
US94920976 Jul 201215 Nov 2016C. R. Bard, Inc.Needle length determination and calibration for insertion guidance system
US952196123 Dec 201120 Dec 2016C. R. Bard, Inc.Systems and methods for guiding a medical instrument
US952644019 Jun 201427 Dec 2016C.R. Bard, Inc.System for placement of a catheter including a signal-generating stylet
US953272422 Sep 20113 Jan 2017Bard Access Systems, Inc.Apparatus and method for catheter navigation using endovascular energy mapping
US954968526 Sep 201424 Jan 2017C. R. Bard, Inc.Apparatus and display methods relating to intravascular placement of a catheter
US955471627 May 201131 Jan 2017C. R. Bard, Inc.Insertion guidance system for needles and medical components
US959748230 Jan 201421 Mar 2017Smart Iv LlcApparatus and method for monitoring catheter insertion
US963603129 Sep 20102 May 2017C.R. Bard, Inc.Stylets for use with apparatus for intravascular placement of a catheter
US964267327 Jun 20129 May 2017Shockwave Medical, Inc.Shock wave balloon catheter with multiple shock wave sources
US964904817 Apr 200916 May 2017C. R. Bard, Inc.Systems and methods for breaching a sterile field for intravascular placement of a catheter
US964915327 Oct 201016 May 2017Holaira, Inc.Delivery devices with coolable energy emitting assemblies
US964915414 Nov 201416 May 2017Holaira, Inc.Non-invasive and minimally invasive denervation methods and systems for performing the same
US96620413 Jun 201330 May 2017Medtronic, Inc.Method and apparatus for mapping a structure
US966880922 Aug 20126 Jun 2017Holaira, Inc.Systems, assemblies, and methods for treating a bronchial tree
US967541231 Oct 201413 Jun 2017Holaira, Inc.Delivery devices with coolable energy emitting assemblies
US968182311 May 201220 Jun 2017C. R. Bard, Inc.Integrated system for intravascular placement of a catheter
US97307158 May 201415 Aug 2017Shockwave Medical, Inc.Shock wave guide wire
US20090264746 *15 Apr 200922 Oct 2009Markowitz H TobyTracking a guide member
US20090264771 *22 Apr 200822 Oct 2009Medtronic Vascular, Inc.Ultrasonic Based Characterization of Plaque in Chronic Total Occlusions
US20150057694 *3 Nov 201426 Feb 2015Frontier Medical Devices, Inc.Method of penetrating an intravascular occlusion
CN103189009A *27 Oct 20113 Jul 2013CR巴德股份有限公司Bioimpedance-assisted placement of a medical device
EP2632360A1 *27 Oct 20114 Sep 2013C.R. Bard Inc.Bioimpedance-assisted placement of a medical device
EP2632360A4 *27 Oct 201121 May 2014Bard Inc C RBioimpedance-assisted placement of a medical device
EP3184067A1 *3 Nov 200928 Jun 2017Ben-Gurion University of The Negev Research and Development AuthorityApparatus for thorombus dissolution/thrombectomy by an electrode catheter device
WO2015171515A1 *4 May 201512 Nov 2015Shockwave Medical, Inc.Shock wave guide wire
Classifications
U.S. Classification606/35
International ClassificationA61B18/04
Cooperative ClassificationA61B2017/22044, A61B17/320758, A61B2017/00026, A61B2017/22042, A61B2017/22094
European ClassificationA61B17/3207R
Legal Events
DateCodeEventDescription
27 Apr 2006ASAssignment
Owner name: MEDTRONIC VASCULAR, INC., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CARNEY, ALAN OLIVER;REEL/FRAME:017820/0575
Effective date: 20060427