SYSTEMS AND METHODS FOR PUNCTURE CLOSURE
Systems, apparatuses and methods are provided for use in closing punctures in vessel walls. An apparatus may have various combinations of an anchoring device, a positioning device and a heating element for closing a puncture within a vessel wall. An anchoring device may be a balloon, an expansible cage, a wire operated T-anchor, and/or a floating anchor. A positioning device may be a balloon, a sponge, and/or an expansible cage. A heating element may be flexible or rigid and preferably provides heat to target tissue through conduction and convection. A heating element may be flat-ended or dome-shaped. The heating element and anchoring device may be positioned a fixed distance apart to sandwich tissue between the heating element and the anchoring device. The heating element may operate in multiple stages. An initial stage may non-permanently adhere the heating element to the tissue and the subsequent stage may close the puncture.
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This application claims priority to U.S. Provisional Patent Application No. 60/935,484, filed Aug. 15, 2007, U.S. Provisional Patent Application No. 60/960,604, filed Oct. 5, 2007, and U.S. Provisional Patent Application No. 61/006,926, filed Feb. 6, 2008, the contents of which are incorporated by reference herein in their entireties.
FIELD OF THE INVENTIONThe invention relates generally to methods and apparatus for treating vasculatures, and, more particularly, to methods and apparatus for post-catheterization closure of punctures in vessel walls.
BACKGROUND OF THE INVENTIONVarious therapeutic and diagnostic procedures, such as arterial catheterization, cause punctures to the vasculature of a patient. Following the performance of such procedures, it is necessary to promote hemostasis quickly and without undue hardship for the patient. Current systems may be either inefficient or painful for a patient.
Generally, needs exist for improved apparatuses and methods for treating vasculatures. More specifically, needs exist for improved apparatuses and methods for efficiently and effectively closing a puncture in a vasculature.
SUMMARY OF THE INVENTIONEmbodiments of the present invention solve many of the problems and/or overcome many of the drawbacks and disadvantages of the prior art by providing apparatuses and method for closing punctures in a wall of a vasculature.
In particular, embodiments of the invention may include an apparatus for closing a puncture in a vessel wall including an anchor shaft, an anchor coupled to a distal end of the anchor shaft wherein the anchor is deployed within a vessel lumen and moved into contact with an inner surface of a vessel wall, a heating element for passing over the anchor shaft to a position a predetermined distance from the anchor, wherein the heating element is not within the vessel lumen, and wherein tissue is compressed between the anchor and the heating element during activation of the heating element.
The anchor may be selected from the group consisting of a balloon, a T-anchor, an expansible cage, a floating anchor, and combinations thereof. A positioning device may pass over the anchor shaft. The positioning device may be selected from the group consisting of a balloon, a sponge, an expansible cage, and combinations thereof. The heating element may be selected from the group consisting of flat-ended, dome-shaped, flattened dome-shaped, and combinations thereof. The heating element may include a patterned conducting element. A coating may be on the heating element. The coating on the heating element may be silicone. The heating element may include two or more segments coupled together to create a unified heating element. The heating element may be flexible. The heating element may be positioned by movement of a shaft of an introducer, wherein the shaft retains the heating element in a compressed position until withdrawal of the introducer shaft. The heating element may be positioned by expansion of a positioning device. The heating element may be rigid. The predetermined distance may be approximately 1-2 mm.
Embodiments may also include a method of closing a puncture in a vessel wall including providing an apparatus having an anchor shaft, an anchor coupled to a distal end of the anchor shaft, and a heating element, inserting the distal end of the anchor shaft into a vessel lumen through a puncture, deploying the anchor within the vessel lumen, inserting the heating element to a position a predetermined distance from the anchor, wherein the heating element is not within the vessel lumen and tissue is compressed between the anchor and the heating element, withdrawing the anchor device through the heating element, activating the heating element, and withdrawing the heating element.
The anchor may be moved against an inner surface of the vessel wall proximate to the puncture prior to inserting the heating element. The anchor may be selected from the group consisting of a balloon, a T-anchor, an expansible cage, a floating anchor, and combinations thereof. A positioning device may be inserted over the anchor shaft. The positioning device may be selected from the group consisting of a balloon, a sponge, an expansible cage, and combinations thereof. The heating element may be selected from the group consisting of a flat-ended heating element, a dome-shaped heating element, a flattened dome-shaped heating element, and combinations thereof. The heating element may have one or more segments coupled together to create a unified heating element. The heating element may be flexible.
Embodiments of the present invention may include an apparatus for closing a puncture in a vessel wall including an anchor shaft, an anchor coupled to a distal end of the anchor shaft wherein the anchor is deployed within a vessel lumen and moved into contact with an inner surface of a vessel wall, and a two-stage heating element passing over the anchor shaft into proximity with an outer surface of the vessel wall opposite the anchor.
The anchor may be selected from the group consisting of a balloon, a T-anchor, an expansible cage, a floating anchor, and combinations thereof. The heating element may be selected from the group consisting of a flat-ended heating element, a dome-shaped heating element, a flattened dome-shaped heating element, and combinations thereof. The first stage of the two-stage heating element may apply heat sufficient to minimally bind the vessel wall to the heating element. The second stage of the two-stage heating element may apply heat sufficient to close the vessel wall. The anchor device may be withdrawn through the heating element prior to the second stage. The vessel wall and tissue may be sandwiched between the anchor and the heating element. The heating element may be controlled by a handheld unit.
Embodiments may also include a method of closing a puncture in a vessel wall including providing an apparatus having an anchor shaft, an anchor coupled to a distal end of the anchor shaft, and a heating element, inserting the distal end of the anchor shaft into a vessel lumen through a puncture, deploying the anchor within the vessel lumen, inserting the heating element into the vicinity of the puncture, initially heating the heating element for minimally adhering tissue to the heating element, withdrawing the anchor device through the heating element, completely activating the heating element, and withdrawing the heating element.
Tissue may be sandwiched between the anchor and the heating element. The anchor may be selected from the group consisting of a balloon, a T-anchor, an expansible cage, a floating anchor, and combinations thereof. The heating element may be selected from the group consisting of a flat-ended heating element, a dome-shaped heating element, a flattened dome-shaped heating element, and combinations thereof.
Embodiments of the present invention may include an apparatus for closing a puncture in a vessel wall including an anchor shaft, an anchor coupled to a distal end of the anchor shaft wherein the anchor is deployed within a vessel lumen and moved into contact with an inner surface of a vessel wall, a heating element adapted to pass over the anchor shaft into proximity with an outer surface of the vessel wall opposite the anchor, and a pass-through device at least partially surrounding the anchor shaft for facilitating passage of the heating element over the anchor shaft into proximity with the outer surface of the vessel wall opposite the anchor.
The anchor may be selected from the group consisting of a balloon, a T-anchor, an expansible cage, a floating anchor, and combinations thereof. The anchor may be a nitinol cage covered by a membrane. The membrane may include at least silicone. The nitinol cage may be substantially planar in an expanded position. The heating element may be selected from the group consisting of a flat-ended heating element, a dome-shaped heating element, a flattened dome-shaped heating element, and combinations thereof. The heating element may be a two-stage heating element. The first stage of the two-stage heating element may apply heat sufficient to minimally bind the vessel wall to the heating element. The second stage of the two-stage heating element may apply heat sufficient to substantially close the vessel wall. The anchor device may be withdrawn through the heating element prior to the second stage. The vessel wall and tissue may be sandwiched between the anchor and the heating element. A guide wire may be deployed within a vessel lumen with the anchor shaft, wherein the guide wire remains within the vessel lumen after removal of the anchor. The guide wire may indicate position of the heating element relative to the vessel wall. The pass-through device may be a roll coupled to the anchor shaft. The roll may have one or more slits for allowing expansion of the roll. The pass-through device may be a dilator. Indicator marks may be located on an anchor shaft coupled to the anchor, wherein the indicators indicate a correct position of the anchor. A large tip may be located on the anchor, wherein the large tip fits flush with a distal end of the heating element when the anchor is withdrawn.
Embodiments may also include a method of closing a puncture in a vessel wall including providing an apparatus having an anchor shaft, an anchor coupled to a distal end of the anchor shaft, a pass-through device at least partially surrounding the anchor shaft, and a heating element, inserting the distal end of the anchor shaft into a vessel lumen through a puncture, deploying the anchor within the vessel lumen, inserting the heating element into the vicinity of the puncture by passing the heating element through the pass-through device, withdrawing the pass-through device after positioning the heating element, activating the heating element, withdrawing the anchor, and withdrawing the heating element.
The pass-through device may be withdrawn by applying pressure away from a distal end of the anchor shaft. Activating the heating element may include initially heating the heating element for minimally adhering tissue to the heating element, and secondarily heating the heating element. The anchor may be withdrawn through the heating element between the initial heating and the secondary heating. Tissue may be sandwiched between the anchor and the heating element. The anchor may be selected from the group consisting of a balloon, a T-anchor, an expansible cage, a floating anchor, and combinations thereof. The heating element may be selected from the group consisting of a flat-ended heating element, a dome-shaped heating element, a flattened dome-shaped heating element, and combinations thereof. A guide wire may be inserted into the vessel lumen with the anchor. Position of the heating element may be measured with the guide wire.
Additional features, advantages, and embodiments of the invention are set forth or apparent from consideration of the following detailed description, drawings and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the detailed description serve to explain the principles of the invention. In the drawings:
Embodiments of the present invention may include apparatus and methods for closing a puncture in a vessel wall. An apparatus of the present invention may have various combinations of an anchoring device, a positioning device and/or a heating element for closing a puncture within a vessel wall. An anchoring device may be a balloon, an expansible cage and/or a wire operated T-anchor. A positioning device may be a balloon, a sponge, and/or an expansible cage. A heating element may be flexible or rigid and preferably provides heat to target tissue through conduction. The heating element may be directly in contact with a vessel wall or may be placed in the vicinity of a vessel wall. These various elements may be used in various combinations as desired and/or depending on a particular application.
Anchoring systems may be used to provide stability during a puncture closure procedure. An anchoring system may act as a locating system for positioning a heating element over a puncture site. Anchoring systems of the present invention may generally be inserted into a vessel through an introducer shaft. The anchoring systems may then be deployed with a vessel lumen and moved into contact with an inner surface of a vessel wall adjacent the puncture site. The anchoring systems described below may be used interchangeably with the various embodiments of the present invention depending on a particular application.
Positioning systems may be used to provide stability during a puncture closure procedure. Positioning systems may also act as a locating system for accurately positioning a heating element over a puncture site. Positioning systems of the present invention may generally be inserted into tissue surrounding a vessel through an introducer shaft. The positioning systems may then be deployed within the tissue. The positioning systems described below may be used interchangeably with the various embodiments of the present invention depending on a particular application.
Heating elements may be used to close a puncture within a vessel wall. Heating elements of the present invention are preferably conduction heating elements which may or may not directly contact target tissue. Heating elements may use resistor-type technology, INCONEL, or other heating element materials. Other types of heating elements, however, such as radio frequency, laser and others, may be used for particular applications. Heating elements may have various shapes for various applications. Flat-ended or flattened heating elements may be preferred for applications where the heating element is inserted perpendicular to a vessel wall. A flat-ended heating element may allow more heating surface to be brought into contact with a vessel wall. Dome-shaped heating elements may preferably be used in applications where the apparatuses of the present invention are inserted at various angles in comparison with a vessel wall. The term “dome-shaped” may be defined for purposes of the specification as any generally curved surface such as, but not limited to, spheres, partial spheres, flattened spheres, and/or circular or elliptical members. In some applications, a dome-shaped heating element may also be desirable in situations where an apparatus is inserted perpendicular to a vessel wall. Heating elements may be rigid or flexible depending on particular applications. Heating elements may have a non-stick coating, such as silicone, TEFLON, or other similar materials to prevent permanent adhering of the vessel walls and/or other tissue to the heating elements. Heating elements may be heated by passing current through a wire or other similar conducting element. Conducting elements may have various configurations to deliver customized heating patterns for particular applications. Various patterns of conducting elements may allow for various treatments.
Heating elements may be coupled to distal ends of heating element shafts. Heating element shafts may be adjacent to and slide coaxially with anchor shafts.
An introducer shaft 109 of an introducer apparatus 111 may be introduced through a vessel wall 113 as shown in
The anchor shaft 117 may be withdrawn from the vessel lumen 115 until the anchor device 103 contacts an inner surface of the vessel wall 113. The positioning device 105 and the heating element may then be located outside of the vessel lumen 115. The positioning device 105 and the heating element 107 may be pushed toward an outer surface of the vessel wall 113 to a predetermined distance from the anchor device 103 as shown in
Alternatively, a first amount of heat may be applied to the vessel wall 173 by the heating element 165. Heat may be applied in an amount sufficient to cause the heating element 165 to “stick” or attach temporarily to the vessel wall 173 and/or intervening tissue, but not permanently bond to the heating element 165. The sufficient amount of heat can be accomplished by way of duration and/or temperature, for example. The heating element 165 may stick without permanently or completely closing the puncture. The heating element 165 may have a non-stick coating, such as silicone, TEFLON, or other similar materials to prevent permanent adhering of the vessel wall 173 and/or intervening tissue to the heating element 165. The first amount of heat may thus allow the heating element 165 to remain in position without the anchor device 163. The anchor device 163 may be withdrawn after the application of the first amount of heat. A second amount of heat may then be applied to the vessel wall 173 and/or intervening tissue by the heating element 165 to close the puncture. The second amount of heat may cause shrinking of the vessel wall 173 and/or intervening tissue such that the puncture is closed. After the closing is complete, the heating element shaft 179 may be withdrawn. This two-stage heating operation may be used with any of the embodiments described herein. Alternatively, a single stage heating operation may be used with any of the embodiments described herein. Furthermore, any number of stages of heating may be provided in accordance with the principles of the invention.
An un-deployed anchor device 143 may be passed into a vessel lumen 155. The un-deployed anchor device 143 may be deployed and moved into contact with an inner surface of a vessel wall 153. The positioning device 145 and the heating element 147 may then be outside the vessel wall 153 and the positioning device 145 and the heating element 147 may be pushed toward an outer surface of the vessel wall 153 until the heating element 147 is near or contacts the vessel wall 153 near or contacting a puncture. The positioning device 145 may be deployed above the puncture site. The heating element 147 may be a rigid, flat-ended heating element or any other suitable heating element. The anchor device 143 may be reduced in volume or un-deployed. The reduced anchor device 143 may be withdrawn out of the vessel lumen 155. The heating element 147 may then be activated to close a puncture in the vessel wall 153. Alternatively, the heating element 147 may be activated in a two-stage heating operation, with the anchor device 143 being withdrawn between the two stages. After the closing is complete, the positioning device 145 may be reduced in volume or un-deployed. The system may then be withdrawn from the patient.
An un-deployed anchor device 183 may be inserted into a vessel lumen 195. The anchor device 183 may be deployed and moved into contact with an inner surface of a vessel wall 193. A heating element shaft 199 may be coupled to a heating element 185 with the heating element 185 at a distal end of the heat element shaft 199. The heating element 185 may preferably be a rigid, dome-shaped heating element but could be any configuration suitable for a particular application. A dome-shaped heating element may increase contact with the vessel wall, as compared to flat heating elements and may force tissue to comport with the contours of the heating element. A preferred dome-shaped heating element may generally be a spherical shape with a flattened distal end. The heating element shaft 199 may be inserted over an anchor shaft (not shown) in an over-the-wire configuration until contacting an outer surface of the vessel wall 193 above a puncture. The heating element 185 may be activated in a single or two-stage heating operation. When closing is complete and the anchor device 183 is un-deployed, the system may be withdrawn from the patient.
As shown in
The floating anchor 477 may be used with any of the positioning devices and/or heating elements described above. The floating anchor 477 would be deployed in a vessel lumen, that the main inflatable anchor body 481 may be moved proximally into contact a puncture at an inside wall of a vessel. After the floating anchor 477 is used, such as in a system for closing a puncture in a vessel wall described herein, the main inflatable anchor body 481 may be deflated by pulling the shaft 485 away from a vessel wall, as shown in
An anchor device 625 may be provided on a distal end of an anchor shaft 629. The anchor shaft 629 may have one or more indicators 631 for determining position of the anchor 625 within a patient. The one or more indicators 631 may show the position of the heating element 603 relative to the anchor device 625. A user may employ a visual reference to identify when the heating element 603 is in a proper position relative to the anchor device 625. In a preferred embodiment, a predetermined indicator 631 may indicate that the heating element 603 is 1 mm, for example, or another preferred distance from the anchor device 625. Other types of arrangements in accordance with the principles of the invention can be used to accomplish a desired fixed distance between an anchor device inside the vessel and a heating element outside the vessel thereby sandwiching the vessel wall between the anchor device and the heating element.
A trigger 608 may be used to lock the heating element 603 in a position relative to an anchor device 625. The heating element 603 on the heating element shaft 607 may slide coaxially over the anchor shaft 629 to position the heating element 603 relative to the anchor device 625. Preferably, the heating element 603 and the anchor device 625 are a predetermined distance apart, such as approximately 1 mm. The trigger 608 may be activated based upon a user visually inspecting the position of one or more indicators 631 on the anchor shaft 629 relative to the location of the heating element shaft 607. The activation of the trigger 608 may lock relative position of the heating element 603 and the anchor device 625. The heating element shaft 607 may have a reference point that indicates a correct positioning of the heating element 603 relative to the anchor device 625. Alternatively, the trigger 608 may initially be in a locked position. The trigger 608 may then be activated to allow relative movement of the heating element 603 and the anchor device 625. This may allow maneuvering of the heating element 603 relative to the anchor 625 while the trigger 608 is activated. Releasing the trigger 608 may lock the relative position of the elements.
A roll 633 may also be disposed at a predetermined distance from the anchor device 625 on the anchor shaft 629. The roll 633 generally facilitates movement of the heating element 603 through tissue as described below. The roll 633 may preferably have a diameter of less than approximately 2.0 mm when used with a 6 Fr introducer shaft. Other combinations of diameters are possible. The roll 633 may preferably have a thickness of approximately 0.1 mm or another minimal thickness in relation to the diameter of the roll 633. Thickness of the roll 633 is preferably minimized, but retains enough strength to prevent tearing of the roll material during operation.
A first ratchet system 626 may be disposed on the handheld unit 611. The first ratchet system 626 may interact with second ratchet system 628 on the anchor shaft 629. Together, the ratchet systems 626, 629 may provide for one way anchor removal locking. One way anchor removal locking may allow the anchor to move toward the handheld unit 611, but not away from the handheld unit 611. This may prevent the anchor device 625 from moving away from the puncture within the vessel lumen. A button release 630 may be provided to unlock the ratchet system. Placement of the anchor device 62 and heating element 603 a desired position relative to one another may be accomplished using one or more indicators 631, tactile sensations, or other methods of determining the relative positions of the anchor device 625 and the heating element 603.
In an embodiment of the present invention, an anchor device 725 may be a nitinol cage 731 as shown in
The nitinol cage 731 may be surrounded with a coating material 743 to prevent passage of blood from a vessel lumen into a puncture in a vessel wall when the nitinol cage 731 is pulled against an inner surface of the vessel wall at the site of the puncture. The coating 743 may be silicone, latex, polyurethane, rubber, rubber-like materials, and/or hyper elastic materials. Preferably, the coating 743 may be made of a material with average strain values between about 600-1000 to accommodate the expansion. Silicone may be preferred for particular embodiments because the strain of silicone may range up to about 1200. The coating 743 preferably allows repeated expansion and contraction without losing elastic performance. Hyperelastic materials may preferably be used to cover the nitinol cage 731 because the nitinol cage 731 may expand from approximately 1 mm to approximately 5-6 mm in a single axis. The coating 743 may form a membrane over the nitinol cage 731. The coating 743 may also prevent injury to tissue and/or the vessel during insertion, expansion, contraction, and/or removal of the nitinol cage 731.
A roll or dilator element may be used with any embodiment described herein. Alternatively, a roll or dilator element may be eliminated altogether in any embodiment described herein.
The roll 809 may at least partially surround the anchor shaft 811 and preferably completely surrounds the anchor shaft 811 to form a cylindrical structure. The roll 809 is preferably made of PTFE, but may be made of any similarly suitable material that may avoid tearing during insertion of a heating element, as shown in
A slit (not shown) may be present along one or more portions of the roll 809. The slit may allow the roll 809 to expand and may allow passage of a heating element 821, as shown in
The anchor shaft 811 may be inserted into the patient through the introducer sheath 801 until a desired position is reached. Desired positioning of the anchor shaft 811 within the patient may be determined by observing the position of an indicator on a portion of the system external to the patient, as shown in
The introducer 801 may then be withdrawn from the vessel lumen 815, and may then be removed completely or partially from the patient.
A distal end of the introducer 801 may be used to open a proximal end of the roll 809 by inserting the distal end of the introducer within the proximal end of the roll 809. This may force open the proximal end of the roll 809 to allow the heating element 821 to enter the roll 809.
A heating element 821 on a heating element shaft 823 may be passed over the anchor shaft 811 in an over-the-wire configuration, as shown in
The heating element 821 may be inserted into an open proximal end 827 of the roll 809, as shown in
The heating element 821 may move through the roll 809 into a desired position near the vessel wall 819 opposite the expanded anchor 807, as shown in
Optionally, a guide wire 808, shown in
The roll 809 may then be retracted from the patient as shown in
Alternatively, the heating element 821 may decouple the roll 809 from the anchor shaft 811 when the heating element 821 reaches a desired position by putting pressure on the connection point between the anchor shaft 811 and the roll 809. The heating element 821 may pass through the coupling point between the anchor shaft 821 and the roll 809 to break the adhesive or other bond and thereby detach the roll 809 from the anchor shaft 821. In alternative embodiments, the roll 809 may be left within the patient during the heating stages.
Once positioned, the heating element 821 may be in direct contact with the vessel wall or may be in close proximity. Preferably, the heating element 821 is in contact with or a predetermined distance from the vessel wall, but does not enter the vessel lumen. The anchor device 807 and the heating element 821 may sandwich the vessel wall and any intervening tissue between them. Any intervening tissue may be compressed between the anchor device 807 and the heating element 821. For example, approximately 1 mm may separate the anchor device 807 and the heating element 821. A locking point or a manual indication external to the patient may ensure determination and/or maintenance of the proper distance between the anchor device 807 and the heating element 821.
A first amount of heat may be applied to the vessel wall by the heating element 821. Heat may be applied in a duration and/or temperature sufficient to cause the heating element to “stick” temporarily to the vessel wall and/or intervening tissue, but not sufficient to close a puncture in the vessel wall. The heating element may have a non-stick coating, such as silicone, TEFLON, etc., to prevent permanent adhering of the vessel wall and/or intervening tissue to the heating element. Silicone is a preferred coating. The first amount of heat may allow the heating element to remain in position without the anchor device. The first amount of heat may shrink the puncture from approximately 2.7 mm, which is approximately the diameter of the introducer shaft, to approximately 1 mm, which is approximately the diameter of the anchor shaft.
After the application of the first amount of heat, the anchor device 807 may be transferred from the deployed position to the un-deployed position, as shown in
After removal of the anchor device 807, a second duration and/or temperature of heat may be applied to the vessel wall and/or intervening tissue by the heating element to close the puncture. The second amount of heat may cause shrinking of the vessel wall and/or intervening tissue such that the puncture is completely or nearly completely closed.
After the second heating step is complete, the heating element shaft may be withdrawn from the patient. The heating element may be uncoupled from the tissue by application of a twisting force on the heating element shaft. The coating on the heating element should be chosen and applied such that the coating allows temporary sticking of the heating element, but not permanent bonding of the heating element thereto. If the guide wire 808 was left within the vessel until after the second heating step, the guide wire 808 may then also be removed. The small diameter of the guide wire 808 may reduce any unwanted bleeding from the tissue caused by its removal.
Application of manual compression for a short period of time, such as approximately one minute, may be required after removal of the system to complete closing of the puncture site and stop any bleeding from the tissue. Any small opening left at the puncture site may be closed by manual compression. The procedure using the system described above may take approximately three minutes and may be followed by approximately one minute of manual compression.
Generally, embodiments of the present invention may close punctures in tissue by applying heat directly to or over a puncture site. Heating elements may produce heat by applying direct current over a metal heating element. This may allow only heat to transfer to the tissue, but not electric current, such as when using radiofrequency during electrocautery, light energy when using lasers or shock waves when using ultrasound.
Two mechanisms for heat flow inside a tissue are:
1. Conduction—meaning that the gradient in temperature within the tissue itself drives the flow.
2. Convection of thermal energy by the perfusing blood.
The heating element may be located just on top of the puncture site so the heat conduction is radial and gradually on the longitudinal and circumferential axis. Regarding the transverse axis, the rapid convection of thermal energy by the blood flow may protect the intima layer from excess thermal effects.
Whereas cauterizing effects of electrocautery and/or electrosurgery can achieve hemostasis by fusion of both sides of the artery and occlusion of the vessel, the present invention may use low voltage for a short time to generate approximately 70°-120° C. temperatures. The thermal effect of the heating element on the artery wall is shrinkage and closure of the puncture.
The main components of an artery wall are collagen and elastin. The collagen molecule is made up of three polypeptide chains, which are stabilized in a triple-helix arrangement by intra-molecular cross links. These molecules are, in turn, aggregated into a parallel pattern to form collagen fibrils. The fibril arrangement may be maintained by intermolecular cross-links and may provide the artery wall tissue with its tensile properties. Intra-molecular cross-links may be reducible covalent aldehyde bonds that are sensitive to heat. When collagen is heated, the heat-labile intra-molecular cross-links may be broken, while the heat-stable intermolecular bonds remain in tension. The collagen shrinkage may be the cumulative effect of the “unwinding” of the triple-helix due to these processes.
The general order of histological change reflected by the thermal effect of the present invention on the artery wall tissue is:
1. Swelling of collagen bands.
2. Thickening of the media layer.
3. Spotty hyalinization of collagen fibers within bands.
4. Increasing regional volumes of diffuse collagen hyalinization.
A preclinical study in accordance with principles of the present invention was performed on swine. An approximately 4.5 mm spherical heating element was applied to an approximately 6 Fr puncture. The preclinical study applied temperatures of 75° C. to 350° C. on top of the puncture made by a 6 Fr introducer for 10 seconds, and followed up with the swine for up to 6 weeks. The histopathology results demonstrate: minimal neointima, increase proteoglycans to a variable extent in the media and scarring of the adventitial without residual necrosis or inflammation. Elastic laminae were intact and no luminal thrombus was identified.
The following are results of testing of a heating element in accordance with principles of the present invention. There were no significant changes seen, other that platelet-lined arteriotomy sites and hemorrhage. At 72 hours, there were no intimal changes, and were no adventitial changes of necrosis of collagen and adventitial vasa vasorum. There was no obvious correlation between the degree of necrosis and temperature. Only one artery, which was exposed at 350° C. heat, showed medial, consisting of medial necrosis with increased proteoglycan, at 72 hours. At 10 days, minimal neointimal was present only in the femoral arteries; the carotid vessels did not exhibit intimal changes. There was minimal persistent necrosis of the adventitial vasa vasorum at 10 days, with inflammation and early fibrosis of the adventitial collagen. Medial changes consisted of regenerative changes with increased proteoglycans, without residual necrosis, and with occasional calcification in areas of puncture sites. At 42 days, there was scarring of the adventitial vasa vasorum without residual necrosis or inflammation. Minimal neointima was present again only in femoral arteries. Medial changes consisted of increased proteoglycans to a variable extent. At all time points, elastic laminae were intact and no luminal thrombus was identified. No particular dose response related effect was noted by quantization of parameters.
In another series of tests on swine, three of four vessels had heat treatment with an approximately 4.5 mm sphere over an approximately 6 Fr puncture. The perforation sites demonstrated fibrosis with healing, with foreign body granuloma in two. The intima demonstrated minimal thickening, to a maximal thickness of 0.33 mm, without stenosis or persistent non-endothelialized thrombus. The media demonstrated loss of smooth muscle cells and increased proteoglycans, with calcification in one of the three treated vessels. The change extended up to 22.5 mm in length. The internal and external elastic laminae were intact with the exception of at the perforation site. The adventitia demonstrated fibrosis, up to 7.5 mm in length. The control artery demonstrated changes consistent with perforation and healing. There were no significant untoward or unexpected complications or tissue effects from the treatment. The persistent changes at 42 days included minimal intimal thickening, medial smooth muscle cell loss, and adventitial fibrosis. The length of the treatment effect suggests that the heat disperses beyond the distance of the heating element itself, possibly due to heating of fluid in the anchor balloon.
Without wishing to be limited by mechanism of action, in a preferred embodiment only, there are three likely main mechanisms operating to close punctures in vessels treated by heating elements of the present invention:
1—Heat-induced fusion of loose periadventitial tissue.
2—Heat-induced clot formation.
3—Thermal shrinkage of collagen and elastin.
The following are assumptions for tissue response to heat:
1. Once the temperature reaches 43°-45° C., cells could die.
2. Any elevation in temperature will increase blood coagulation (in stasis).
3. Collagen denaturation initiates at approximately around 65° C., with maximal shrinkage effect approximately around 85° C.
4. Fusion of loose connective tissue requires a temperature of greater than 115° C.
5. Regarding time for which heat may be applied: At 43° C., changes may be reversible for 30-50 minutes; at 45° C. or greater, this time may shorten dramatically. Collagen shrinkage effect at 85° C. may reach maximal effect at 1-15 seconds. Connective tissue may burn and char within 1 second of contact with a probe tip at greater than 115° C.
The following are exemplary technical specifications for a heating element. These are only for illustrative purposes and other configurations and specifications may be used.
1. The orifice diameter of a 6 Fr introducer sheath used in many diagnostic and therapeutic procedures is approximately 2.7 mm (external size). Assuming no post-withdrawal contraction of tissue surrounding the puncture, and 1.15 mm overlap of the introducer sheath and the heating element—the heating element diameter may be approximately 5.0 mm. Post-withdrawal contraction may reduce the necessary size of the heating element. Reduced overlap may also reduce the necessary size of the heating element. In general, the size of the heating element should be at least slightly larger than the puncture.
2. Heat production and conduction should preferably be nearly uniform over the entire surface area of the heating element.
3. The heating element may produce approximately 115° C. for approximately 15 seconds in a single cycle. The handheld unit may allow for determination of the heating temperature, duration and number of cycles. The handheld unit may have preferred combinations pre-programmed. The heating element may operate in one or more cycle of approximately 15 watts per cycle for approximately 5 seconds per cycle. Wattage may range from approximately 1 watt to approximately 25 watts per cycle. Duration of cycles may range from approximately 1 second to approximately 10 seconds. Preferably, two cycles may be used.
Although the foregoing description is directed to the preferred embodiments of the invention, it is noted that other variations and modifications will be apparent to those skilled in the art, and may be made without departing from the spirit or scope of the invention. Moreover, features described in connection with one embodiment of the invention may be used in conjunction with other embodiments, even if not explicitly stated above.
Claims
1. An apparatus for closing a puncture in a vessel wall comprising:
- an anchor shaft,
- an anchor coupled to a distal end of the anchor shaft wherein the anchor is deployed within a vessel lumen and moved into contact with an inner surface of a vessel wall,
- a heating element for passing over the anchor shaft to a position a predetermined distance from the anchor, wherein the heating element is not within the vessel lumen, and
- wherein tissue is compressed between the anchor and the heating element during activation of the heating element.
2. The apparatus of claim 1, wherein the anchor is selected from the group consisting of a balloon, a T-anchor, an expansible cage, a floating anchor, and combinations thereof.
3. The apparatus of claim 1, further comprising a positioning device passing over the anchor shaft.
4. The apparatus of claim 3, wherein the positioning device is selected from the group consisting of a balloon, a sponge, an expansible cage, and combinations thereof.
5. The apparatus of claim 1, wherein the heating element is selected from the group consisting of flat-ended, dome-shaped, flattened dome-shaped, and combinations thereof.
6. The apparatus of claim 1, wherein the heating element comprises a patterned conducting element.
7.-30. (canceled)
31. A method of closing a puncture in a vessel wall comprising:
- providing an apparatus comprising: an anchor shaft, an anchor coupled to a distal end of the anchor shaft, and a heating element,
- inserting the distal end of the anchor shaft into a vessel lumen through a puncture,
- deploying the anchor within the vessel lumen,
- inserting the heating element into the vicinity of the puncture,
- initially heating the heating element for minimally adhering tissue to the heating element,
- withdrawing the anchor device through the heating element,
- completely activating the heating element, and
- withdrawing the heating element.
32. The method of claim 31, further comprising sandwiching tissue between the anchor and the heating element.
33. The method of claim 31, wherein the anchor is selected from the group consisting of a balloon, a T-anchor, an expansible cage, a floating anchor, and combinations thereof.
34. The method of claim 31, wherein the heating element is selected from the group consisting of a flat-ended heating element, a dome-shaped heating element, a flattened dome-shaped heating element, and combinations thereof.
35.-52. (canceled)
53. A method of closing a puncture in a vessel wall comprising:
- providing an apparatus comprising: an anchor shaft, an anchor coupled to a distal end of the anchor shaft, a pass-through device at least partially surrounding the anchor shaft, and a heating element,
- inserting the distal end of the anchor shaft into a vessel lumen through a puncture,
- deploying the anchor within the vessel lumen,
- inserting the heating element into the vicinity of the puncture by passing the heating element through the pass-through device,
- withdrawing the pass-through device after positioning the heating element,
- activating the heating element,
- withdrawing the anchor, and
- withdrawing the heating element.
54. The method of claim 53, wherein the pass-through device is withdrawn by applying pressure away from a distal end of the anchor shaft.
55. The method of claim 53, wherein activating the heating element comprises initially heating the heating element for minimally adhering tissue to the heating element, and secondarily heating the heating element.
56. The method of claim 55, wherein the anchor is withdrawn through the heating element between the initial heating and the secondary heating.
57. The method of claim 53, further comprising sandwiching tissue between the anchor and the heating element.
58. The method of claim 53, wherein the anchor is selected from the group consisting of a balloon, a T-anchor, an expansible cage, a floating anchor, and combinations thereof.
59. The method of claim 53, wherein the heating element is selected from the group consisting of a flat-ended heating element, a dome-shaped heating element, a flattened dome-shaped heating element, and combinations thereof.
60. The method of claim 53, further comprising inserting a guide wire into the vessel lumen with the anchor.
61. The method of claim 60, further comprising measuring position of the heating element with the guide wire.
Type: Application
Filed: Jan 17, 2013
Publication Date: May 23, 2013
Applicant: Cardiodex Ltd. (Cesarea)
Inventor: Cardiodex Ltd. (Cesarea)
Application Number: 13/744,098
International Classification: B23P 6/00 (20060101);