AU2010202027B2

AU2010202027B2 - Apparatus

Info

Publication number: AU2010202027B2
Application number: AU2010202027A
Authority: AU
Inventors: Ranier Betelia; Hung Van Vo
Original assignee: WL Gore and Associates Inc
Current assignee: WL Gore and Associates Inc
Priority date: 2002-06-27
Filing date: 2010-05-19
Publication date: 2011-12-22
Anticipated expiration: 2023-06-25
Also published as: AU2010202028A1; AU2010202027A1; AU2010202028B2; AU2007200632A1; AU2007200632B2

Abstract

22 20 29 22 26 (PRIOR ART) (PRIOR ART) This invention relates to apparatus and methods for removing emboli during vascular interventions. More s particularly, the apparatus and methods of the present invention provide a catheter having an occlusion balloon of uniform thickness that facilitates retrograde flow and removes emboli from a treatment vessel via a funnel shaped taper of the occlusion balloon. 2281627_1 (GHMatters) 19105/10

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Divisional Patent Applicant (s) GORE ENTERPRISE HOLDINGS, INC. Invention Title: Apparatus The following statement is a full description of this invention, including the best method for performing it known to me/us: - 2 Apparatus Field of the Invention This invention relates to apparatus and methods for s removing emboli during vascular interventions. Background of the Invention Today there is a growing need to provide controlled access and vessel management during such procedures as stenting, 10 atherectomy and angioplasty. Generally during these procedures there is a high opportunity for the release of embolic material. The emboli may travel downstream from the occlusion, lodging deep within the vascular bed and causing ischemia. The resulting ischemia may pose a 15 serious threat to the health or life of a patient if the blockage forms in a critical area, such as the heart, lungs, or brain. Several previously known apparatus and methods attempt to 20 remove emboli formed during endovascular procedures by aspirating the emboli out of the vessel of interest using a catheter having an occlusion balloon. These previously known occlusion balloons, however, have various drawbacks, including variability in deployment of the balloon to the 25 desired shape, inefficiency in removing emboli, and/or high cost and complicated processes associated with manufacturing the balloon. In applicant's co-pending U. S. patent application Serial 30 No. 09/418,727, filed October 15, 1999, which is incorporated herein by reference in its entirety, applicant describes the use of a bell or pear-shaped 2970662_1 (GHMatters) P55482 AU.3 22111/11 -3 occlusion balloon disposed on the distal end of an arterial catheter. The occlusion balloon comprises a compliant material having a variable thickness along its length to provide a bell-shape when inflated. The balloon 5 is affixed to distal end of the catheter so that a distal portion of the balloon extends beyond the distal end of the catheter to provide an atraumatic tip or bumper for the catheter. 10 The balloon of that catheter may be formed using previously known techniques, such as varying the thickness of the balloon wall to achieve the preferred bell-shape in the deployed position. Such processes, however, can lead to variability in the final product due to the 15 manufacturing process. Because variable thickness balloons present greater difficulties during manufacture than balloons having uniform wall thickness, the cost of such balloons may be higher. 20 In view of the foregoing limitations of previously known devices, it would be desirable to provide an apparatus for removing emboli from a vessel comprising an occlusion balloon of uniform thickness to enhance manufacturability of the occlusion balloon. 25 It also would be desirable to provide an apparatus for removing emboli from a vessel comprising an occlusion balloon of uniform thickness to reduce manufacturing cost and enhance product yield. 30 It further would be desirable to provide an apparatus for removing emboli from a vessel comprising a catheter having an occlusion balloon of uniform thickness that facilitates retrograde flow and efficiently removes emboli. 35 Summary of the Invention 2281827_1 (GHMatters) 19f05/10 - 4 According to an aspect of the present invention there is provided an apparatus suitable for removing emboli from a vessel, the apparatus comprising: a catheter having a proximal section configured to extend outside a patient, a 5 hemostatic port disposed on the proximal section, an occlusive distal section, a main body extending therebetween, and a lumen extending therethrough the catheter having a fluid impermeable cover; and an outer sheath disposed to slide longitudinally along the 10 catheter; wherein the main body has a contracted delivery diameter when disposed within the outer sheath and a radially expanded deployed diameter when deployed from the outer sheath. 15 According to an aspect of the present invention there is provided a method for enhancing flow within a catheter, the method comprising: providing a catheter disposed in a contracted state within an outer sheath, the catheter comprising a proximal section configured to extend outside 20 a patient, a hemostatic port disposed on the proximal section, an occlusive distal section, a main body extending therebetween, and a lumen extending therethrough, the catheter having a fluid impermeable cover; inserting the catheter and outer sheath into a 25 patient's vasculature to a desired location; retracting the outer sheath proximally to deploy the occlusive distal section; and further retracting the outer sheath proximally to cause radial expansion of the main body. 30 Brief Description of the Drawings Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments, in which: 2970662_1 (GHMatters) P55482.AU.3 22/11/11 - 4a Figures lA-lB are, respectively, side and sectional views of a previously known occlusion balloon in contracted and deployed states; 5 Figures 2A-2B are, respectively, a schematic view of apparatus in accordance with the present invention and a cross-sectional view along line A--A of Figure 2A; Figures 3A-3B are side sectional views illustrating a 10 preferred configuration of the distal end of the catheter of Figure 2; Figures 4A-4B are side sectional views of the occlusion balloon of the present invention in contracted and 15 deployed states, respectively; and Figure 5 is a schematic view of apparatus of the present invention being used during an interventional procedure. 29706621 (GHMatters) P55482.AU.3 22/11/11 -5 Description of the Preferred Embodiments Referring to Figures 1A-1B, a bell-shaped occlusion balloon, as described in applicant's commonly assigned 5 allowed U. S. patent application Serial No. 09/418,727, filed May 8, 2001, which is incorporated herein by reference, is described. Occlusion balloon 20 is shown in contracted and deployed states in Figures 1A and 1B, respectively. Balloon 20 is affixed to distal end 26 of 10 catheter 22, for example, by gluing or a melt-bond, so that opening 27 in balloon 20 leads into lumen 28 of catheter 22. Balloon 20 preferably is wrapped and heat treated during manufacture so that distal portion 29 of the balloon extends beyond the distal end of catheter 22 is and provides an atraumatic tip or bumper for the catheter. In accordance with manufacturing techniques which are known in the art, occlusion balloon 20 comprises a compliant material, such as polyurethane, latex or polyisoprene which has variable thickness along its length 20 to provide a bell-shape when inflated. As described hereinabove, the variable thickness characteristic of occlusion balloon 20, which is used to deploy the balloon to the preferred bell-shape, presents 25 certain manufacturing challenges. In particular, manufacturing a balloon having a variable wall thickness can lead to reduced yield due to variability of the manufacturing process. Additionally, a variable thickness balloon may be difficult to manufacture and may have a 30 higher cost relative to a balloon having a uniform thickness. Referring now to Figures 2, a first embodiment of apparatus constructed in accordance with principles of the 35 present invention is described. Apparatus 40 comprises catheter 41 having proximal and distal ends and working lumen 58 extending therethrough. Catheter 41 comprises 2281827_1 (GHMatters) 19105/10 -6 occlusion balloon 42 having proximal and distal ends affixed to the distal end of catheter 41, and preferably comprises radiopaque marker band 65 disposed at the distal end of catheter 41 to facilitate positioning of the distal 5 end of the catheter. Occlusion balloon 42 comprises a uniform thickness material having a contracted state suitable for insertion into a vessel and a deployed state in which occlusion 10 balloon 42 occludes antegrade flow in the vessel. In the deployed state, occlusion balloon 42 comprises distal taper 66 that is configured to provide a funnel-shaped transition into working lumen 58 so that blood flows in a non-turbulent fashion from a treated vessel into catheter 15 41. Additionally, distal edge 68 is configured to be in close proximity with an inner wall of a vessel to facilitate blood flow into catheter 41 and efficiently remove emboli. 20 Catheter 41 preferably comprises inner layer 60 of low friction polymeric material, such as polytetrafluoroethylene ("PTFE"), covered with a layer of flat stainless steel wire braid 61 and polymer cover 62 (e. g. , polyurethane, polyethylene, or PEBAX), as shown 25 in Figure 2B. Working lumen 58 is defined as a lumen within an interior surface of inner layer 60. Inflation lumen 63 preferably is disposed within polymer cover 62 so that the inflation lumen does not substantially increase the overall profile of catheter 41. 30 Apparatus 40 preferably further includes proximal hemostatic port 43, e. g., a Touhy-Borst connector, inflation port 44, and blood outlet port 48. Inflation port 44 is coupled to inflation lumen 63, which in turn is 35 coupled to occlusion balloon 42. Proximal hemostatic port 43 and working lumen 58 of catheter 41 are sized to permit interventional devices, such as angioplasty balloon 22818271 (GHMatters) 19/05/10 - 7 catheters, atherectomy devices and stent delivery systems to be advanced through the working lumen when a guidewire (not shown) is positioned within the working lumen. 5 Blood outlet port 48, which is in fluid communication with working lumen 58, may be coupled to an external aspiration device, e. g., a syringe, to cause blood flow distal of occlusion balloon 42 to flow into working lumen 58. Alternatively, in a preferred embodiment, blood outlet 1o port 48 may be coupled to a venous return catheter to form an arterial-venous shunt suitable for providing retrograde flow in a treatment vessel. This aspiration embodiment comprising an arterial-venous shunt is described in detail in applicant's commonly-assigned, above-incorporated U. S. is patent application Serial No. 09/418,727. Referring now to Figures 3, a preferred configuration of catheter 41 and a preferred method for affixing occlusion balloon 42 to the distal end of catheter 41 are described. 20 In Figure 3A, the distal end of catheter 41 is shown from a side sectional view as comprising inner layer 60 covered with a layer of flat stainless steel wire braid 61 and polymer cover 62. Radiopaque marker band 65 preferably is disposed at the distal end of catheter 41 between wire 25 braid 61 and polymer cover 62, as shown in Figure 3A. In accordance with principles of the present invention, occlusion balloon 42 comprises a uniform thickness along its length, as illustrated in Figures 3A-3B. 30 In a preferred method of manufacture, distal end 50 of occlusion balloon 42 is positioned atop polymer cover 62 near the distal end of catheter 41 and just distal of opening 70 of polymer cover 62, as shown in Figure 3A. Distal end 50 of occlusion balloon 42 then is affixed to 35 polymer cover 62, preferably using a melt-bond or, alternatively, using a biocompatible glue. At this time, proximal end 52 of occlusion balloon 42 extends freely 2281827_1 (GHMatters) 19105/10 - 8 beyond the distal end of catheter 41, as shown in Figure 3A. For purposes of clarifying terminology used herein, although proximal end 52 of occlusion balloon 42 appears situated distal of distal end 50 in Figure 3A, this is s because proximal end 52 will subsequently be everted to extend proximal of distal end 50, as described hereinbelow. In a next manufacturing step, distal section 51 of 10 occlusion balloon 42, which is situated just proximal of distal end 50, is melt-bonded to at least one polymeric layer of catheter 41. Specifically, in a preferred embodiment, distal section 51 of occlusion balloon 42 is melt-bonded to distalmost end 85 of inner layer 60 and, 15 optionally, to distalmost end 87 of polymer cover 62 to form fusion joint 67, as shown in Figure 3A. The melt bonding of the plurality of polymeric materials at fusion joint 67 provides substantially seamless transition 72 between occlusion balloon 42 and inner layer 60. 20 Additionally, because fusion joint 67 is formed from a plurality of compliant polymeric materials, fusion joint 67 is capable of achieving a flexible range of motion. Proximal end 52 of occlusion balloon 42 then is everted so 25 that it extends proximally and radially outward from catheter 41, as shown in Figures 3B and 4A. Proximal end 52 is affixed to polymer cover 62, preferably using a melt-bond or, alternatively, using a biocompatible glue, at a distance between about 10-20 mm proximal of the 30 distal end of catheter 41, as shown in Figure 4A. This creates inflation chamber 74 between polymer cover 62 and an interior surface of balloon 42. opening 70, which is disposed in a lateral surface of polymer cover 62, is in fluid communication with inflation lumen 63 and inflation 35 chamber 74, as shown in Figure 3B. Proximal end 52 of occlusion balloon 42 may be stretched while it being 2281827_1 (GHMatters) 19/05/10 - 9 affixed to polymer cover 62 so that apparatus 40 may achieve a reduced profile in the contracted state. The fusion of occlusion balloon 42 to catheter 41 at s fusion joint 67 and subsequent eversion of the balloon creates substantially seamless transition 72 into working lumen 58, as shown in Figure 3B. In accordance with principles of the present invention, the provision of substantially seamless transition 72 may help reduce flow 10 impedance into working lumen 58 and enhance flow within a treated vessel. Referring now to Figures 4A-4B, deployment of apparatus 40 within vessel V of a patient is described. In Figure 4A, is occlusion balloon 42 is shown in a contracted state suitable for percutaneous and transluminal insertion into a patient's vessel. Occlusion balloon 42 is inflated via inflation port 44, inflation lumen 63 and opening 70, and deploys to a predetermined configuration having proximal 20 taper 64 and distal taper 66, as shown in Figure 4B. The predetermined configuration may be determined, for example, using a pre-moulding process in accordance with manufacturing techniques that are known in the art. In the deployed state, an outer surface of central section 75, 25 which is formed between proximal and distal tapers 64 and 66, is substantially flush with an inner wall of vessel V. As will be understood by those skilled in the art, the expanded diameter of central section 75 may be sized accordingly for different vessels. 30 Distal edge 68 is defined as a section of occlusion balloon 42 that is formed between central section 75 and distal taper 66. In the deployed state, distal edge 68 is configured to be in close proximity with an inner wall of 35 vessel V to facilitate blood flow into working lumen 58 and efficiently remove emboli. 2281827_1 (GHMatters) 19/05/10 - 10 Distal taper 66 provides a funnel-shaped flow transition from distal edge 68 into working lumen 58. Additionally, as described hereinabove, fusion joint 67 provides substantially seamless transition 72 from occlusion 5 balloon 42 into working lumen 58 due to the melt-bond between balloon 42 and inner layer 60 of catheter 41. Referring now to Figure 5, a preferred method for using apparatus 40 of Figure 2A during an interventional 10 procedure, such as balloon angioplasty, is described. In a first step, guidewire 83 is inserted into a patient's vasculature and a distal end of guidewire 83 is disposed just proximal of stenosis S, which is located in vessel V. A dilator (not shown) that is disposed within catheter 41 15 then is inserted over guidewire 83 to advance catheter 41 to a desired position proximal of stenosis S. When catheter 41 is properly positioned, e. g. , as determined under fluoroscopy using radiopaque marker band 65, the dilator may be removed. Occlusion balloon 42 then is 20 inflated via inflation port 44 of Figure 2A, preferably using a radiopaque contrast solution, to occlude antegrade flow in vessel V. Aspiration is provided through working lumen 58 of catheter 41 to cause retrograde flow to occur in vessel V distal of occlusion balloon 42, as illustrated 25 by the arrows in Figure 5. Aspiration may be provided through working lumen 58 via blood outlet port 48 using an external aspiration device, e. g., a syringe, or alternatively using a venous return 30 catheter to form an arterial-venous shunt, as described hereinabove. An interventional instrument, such as conventional angioplasty balloon catheter 80 having balloon 82, may be 35 loaded through hemostatic port 43 and working lumen 58 and positioned within stenosis S, preferably via guidewire 83. Hemostatic port 43 is closed and the angioplasty balloon 22818271 (GHMatters) 19105/10 - 11 is actuated to disrupt stenosis S. As seen in Figure 5, emboli E formed during the interventional procedure are directed into working lumen 58 via the retrograde flow established. 5 Occlusion balloon 42 provides a substantially uniform funnel-shaped transition from an inner wall of vessel V into working lumen 58 of catheter 41. Distal edge 68, which is configured to be in close proximity with an inner 10 wall of vessel V, facilitates flow into working lumen 58 and efficiently removes emboli. Additionally, the funnel shaped transition provided by distal taper 66 and substantially seamless transition 72 into the working lumen via fusion joint 67 improves retrograde flow 15 dynamics into working lumen 58. Advantageously, because the present invention utilises an occlusion balloon having a uniform thickness and relies on pre-moulding of the occlusion balloon to obtain the 20 desired deployed shape, a variable thickness occlusion balloon is not required. As noted hereinabove, use of an occlusion balloon having a uniform thickness provides several advantages, including enhanced manufacture, reduced cost and increased reliability. 25 While preferred illustrative embodiments of the invention are described above, it will be apparent to one skilled in the art that various changes and modifications may be made. The appended claims are intended to cover all such 30 changes and modifications that fall within the true spirit and scope of the invention. In the claims which follow and in the preceding description of the invention, except where the context 35 requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, 2281827_1 (GHMatters) 19105/10 - 12 i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 5 It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. 10 2970662_1 (GHMatters) P55482.AU.3 22/11/11

Claims

1. Apparatus suitable for removing emboli from a vessel, the apparatus comprising: 5 a catheter having a proximal section configured to extend outside a patient, a hemostatic port disposed on the proximal section, an occlusive distal section, a main body extending therebetween, and a lumen extending therethrough the catheter having a fluid impermeable io cover; and an outer sheath disposed to slide longitudinally along the catheter; wherein the main body has a contracted delivery diameter when disposed within the outer sheath and a 15 radially expanded deployed diameter when deployed from the outer sheath.

2. The apparatus of claim 1 wherein the proximal section comprises a fixed diameter. 20

3. The apparatus of claim 1 or 2 wherein the occlusive distal section comprises a contracted state and an expanded state suitable for occluding flow in a vessel. 25

4. The apparatus of claim 3 wherein the occlusive distal section further comprises a wire weave configuration that forms a predetermined shape in the expanded state.

5. The apparatus of claim 4 wherein the predetermined 30 shape of the occlusive distal section, when deployed, is substantially flush with the vessel wall at a distal portion and tapers in proximally to connect to (be main body of the catheter. 35

6. The apparatus of any preceding claim wherein the occlusive distal section comprises Nitinol. 2970662_1 (GHMatters) P55482.AU 3 22111111 - 14

7. The apparatus of any preceding claim wherein the main body comprises a plurality of individually compressible hoops. 5

8. The apparatus of claim 7 wherein the individually compressible hoops are enclosed within an elastomeric polymer coating.

9. The apparatus of claim 7 or 8 further comprising a 10 plurality of linkages connecting the individually compressible hoops.

10. The apparatus of any one of claims 1 to 6 wherein the main body comprises a spiral configuration having a 15 plurality of compressible spiral-shaped wires.

11. The apparatus of claim 10 wherein the compressible spiral-shaped wires are enclosed within an elastomeric polymer coating. 20

12. The apparatus of claim 10 or 11 further comprising a plurality of linkages connecting the compressible spiral shaped wires. 25

13. The apparatus of any preceding claim wherein the main body consists of a nickel-titanium alloy.

14. The apparatus of any preceding claim wherein the main body spans a greater distance than the proximal section. 30

15. The apparatus of any preceding claim wherein the diameter of the main body in an expanded state is larger than the diameter of the proximal section. 3s

16. The apparatus of any preceding claim wherein the outer sheath is positioned in a distalmost position to 2970662_1 (GHMatters) P55482.AU.3 22/11/11 - 15 compress the main body and occlusive distal section within the outer sheath.

17. A method for enhancing flow within a catheter, the 5 method comprising: providing a catheter disposed in a contracted state within an outer sheath, the catheter comprising a proximal section configured to extend outside a patient, a hemostatic port disposed on the proximal section, an 10 occlusive distal section, a main body extending therebetween, and a lumen extending therethrough, the catheter having a fluid impermeable cover; inserting the catheter and outer sheath into a patient's vasculature to a desired location; retracting 15 the outer sheath proximally to deploy the occlusive distal section; and further retracting the outer sheath proximally to cause radial expansion of the main body. 20

18. The method of claim 17 further comprising: performing an interventional procedure; and aspirating emboli generated during the interventional procedure into the lumen of the catheter. 25

19. The method of claim 18 further comprising: at the conclusion of the interventional procedure, advancing the outer sheath to contract the main body and the occlusive distal section; and withdrawing the catheter and outer sheath from the 30 patient's vasculature.

20. An apparatus suitable for removing emboli, or a method for enhancing flow within a catheter, substantially as herein described with reference to Figures 2 to 5. 2970662_1 (GHMatters) P55482.AU.3 22/11/11