Method and system for placing embolic filter in aortic arch

Abstract

To provide a method and a system for placing am embolic filter in a good aortic arch.SOLUTION: An embolic filter positioning system includes a vascular delivery sheath, a filter catheter, a self-expanding embolic filter attached to a distal end of the filter catheter, and an elongate dilator having a tapered dilator tip. The elongate dilator is slidably received in a central lumen of the filter catheter, and the filter catheter is slidably received in the open lumen of the vascular delivery sheath. The tapered dilator tip is positioned distally of the distal end of the vascular delivery sheath, and the self-expanding embolic filter is radially constrained in a proximal portion of the open lumen of the vascular delivery sheath. The tapered dilator tip has an expanded configuration where it covers the open distal end of the vascular delivery sheath and facilitates entry though an arteriotomy and a contracted configuration where it can be retracted through the central lumen of the filter catheter.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of Provisional Patent Application Docket No. 63 / 151,508 (Attorney Docket No. 41959-715.101), filed February 19, 2021, the complete disclosure of which is incorporated herein by reference.

[0002] 1. Field of the Invention The present invention relates generally to medical devices and methods, and more particularly to methods and systems for placing an embolic filter within a patient's aortic arch prior to transcatheter aortic valve replacement (TAVR) and other aortic valve procedures.

[0003] Transcatheter aortic valve replacement (TAVR) has become a preferred alternative to open-heart surgery for many patients requiring aortic valve replacement. The most common approach is "transfemoral," in which the femoral artery is accessed through a small incision in the groin, and the replacement valve is advanced from the femoral artery into the descending aorta and across the aortic arch using a specialized delivery catheter.

[0004] While highly successful, transfemoral and other TAVR procedures can release emboli and present a significant risk of cerebral embolism. Embolic particles, such as thrombus, atheroma, and lipids, can become dislodged by the advancement and manipulation of the delivery catheter, enter the bloodstream, and embolize within the brain or other downstream vital organs. Cerebral embolism can lead to neuropsychological impairment, stroke, and even death. Other downstream organs can also be damaged by embolism, resulting in decreased function or organ failure.

[0005] For these reasons, the use of embolic protection systems during TAVR and other catheter-based procedures has been proposed. For example, commonly owned U.S. Pat. No. 10,617,509 describes a cylindrical embolic filter and a system for placing the filter in a patient's aortic arch to reduce the risk of cerebral aneurysms and other negative consequences caused by embolic release during TAVR. The embolic filter is placed by introducing a conventional dilator and access sheath assembly 10 through the femoral artery, as shown in FIG. 1 . The sheath assembly 10 includes a tubular access sheath 12 and a dilator 14 having a tapered distal tip 16. The dilator tip 16 is solid, and the dilator 14 has an axially extending guidewire lumen (not shown) for receiving a guidewire 18 therethrough. Because the dilator 14 and tip 16 are solid and one piece, the entire dilator must be removed from the access sheath 12 to free the access sheath lumen and introduce a filter delivery catheter. As described in U.S. Pat. No. 10,617,509, a separate filter delivery catheter is introduced into the access sheath lumen using a peel-away sheath after removing the dilator. While fully operational, the time required to remove the dilator, place the peel-away sheath, and introduce the filter delivery catheter is significant and adds to the overall procedure time.

[0006] For these reasons, it would be advantageous to provide improved methods and systems for introducing embolic filters into a patient's aortic arch for embolic protection during TAVR and other cardiac and vascular procedures. In particular, it would be advantageous to reduce the number of steps required to deploy such an embolic filter and / or reduce overall procedure time. At least some of these goals will be met by the invention(s) described and claimed herein. [Background technology]

[0007] 2. Description of Background Technology US 10,617,509 is described above. WO 2017 / 116828 and US 2020 / 0197151 are related to US 10,617,509. Other devices for inhibiting cerebral embolism are described in the following co-pending patents and patent applications: U.S. Pat. No. 10,166,094 for a catheter with an integrated embolic protection device; U.S. Pat. No. 9,877,821 for an introducer sheath with embolic protection; U.S. Pat. No. 6,254,563 for a perfused shunt apparatus and method; U.S. Pat. App. No. 2010 / 0312268 for an embolic protection device; U.S. Pat. App. No. 2004 / 0215167 for an embolic protection device; PCT Application No. WO2004 / 019817 for an embolic protection device; U.S. Pat. No. 6,371,935 for an aortic catheter with a flow distributor and a method for preventing cerebral embolism; No. 6,361,545 for a filter catheter, U.S. Pat. No. 6,254,563 for a perfusion shunt apparatus and method, U.S. Pat. No. 6,139,517 for a perfusion shunt apparatus and method, U.S. Pat. No. 6,537,297 for a method for protecting a patient from emboli during surgery, U.S. Pat. No. 6,499,487 for an implantable cerebral protection device and method of use, U.S. Pat. No. 5,769,816 for a cannula with an associated filter, and U.S. Patent Application No. 2003 / 0100940 (incorporated herein by reference) for an implantable intraluminal protection device for stabilizing atheroma and a method of using the same. See also U.S. Pat. Nos. 8,419,677 and 2012 / 0109056. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 10,617,509 [Patent Document 2] International Publication No. 2017 / 116828 [Patent Document 3] US Patent Application Publication No. 2020 / 0197151 Summary of the Invention [Means for solving the problem]

[0009] In a first aspect, the present invention provides a method for positioning an embolic filter within a patient's aortic arch. The method includes providing an embolic filter positioning assembly including a dilator component that facilitates introduction into the patient's vasculature and reduces the steps and time required to place the embolic filter within the aortic arch. The embolic filter positioning assembly includes: (1) a vascular delivery sheath; (2) a filter catheter slidably received within an open lumen of the vascular delivery sheath; (3) an elongated dilator having a guidewire lumen slidably received within a central lumen of the filter catheter; (4) a tapered dilator tip attached to the distal end of the elongated dilator; and (5) an embolic filter carried on a distal portion of the filter catheter. The tapered dilator tip is expanded and positioned so as to extend distally beyond and cover the open distal end of the vascular delivery sheath, and the expanded tapered dilator tip of the embolic filter positioning assembly is introduced through the arteriotomy over a first guidewire received within the guidewire lumen of the elongate dilator and into the patient's arterial vasculature. The distal end of the embolic filter positioning assembly is advanced to position the embolic filter carried on the distal portion of the filter catheter within the patient's aortic arch, and the distal portion of the vascular delivery sheath is retracted from over the embolic filter, causing the embolic filter to expand within the patient's aortic arch. The tapered dilator tip can then be retracted, and the tip retracted proximally into or through the catheter lumen of the filter catheter.

[0010] In some embodiments of these methods, expanding the tapered dilator tip may include expanding the tapered dilator tip, and contracting the tapered dilator tip may include deflating the tapered dilator tip.

[0011] In some examples of these methods, the tapered dilator tip may have a conical geometry with a base, and positioning the tapered dilator tip to extend distally beyond and cover the open distal end of the vascular delivery sheath includes removably mating the base with the open distal end of the vascular delivery sheath. In some cases, the base of the tapered dilator tip may be cylindrical and configured to fit inside the open distal end of the vascular delivery sheath.

[0012] In some embodiments of these methods, the proximal end of the embolic filter may be closed and the filter may be retracted back into the vascular delivery sheath. In particular instances, closing the proximal end of the embolic filter may include tightening a loop on the proximal end of the embolic filter.

[0013] In some embodiments of these methods, the embolic filter self-expands within the patient's aortic arch after a distal portion of the vascular sheath is retracted from over the embolic filter.

[0014] In a second aspect, the present invention provides a method for implanting a prosthetic aortic valve within a patient's aortic arch. The method includes placing an embolic filter within the patient's aortic arch by any of the methods described above and elsewhere herein. The prosthetic aortic valve is advanced through the embolic filter, and the prosthetic aortic valve is deployed within the patient's aortic annulus while the embolic filter remains in place within the aortic arch.

[0015] In some embodiments of such valve implantation methods, advancing the prosthetic aortic valve through the embolic filter includes removing the elongated dilator from the central lumen of the filter catheter, leaving the first guidewire in place within the central lumen of the filter catheter. The first guidewire is then exchanged for an angiography pigtail catheter, and one or more valve placement guidewires are advanced through the embolic filter and across the aortic arch parallel to the embolic filter positioning assembly. A valve placement catheter carrying the prosthetic valve is then advanced over the one or more valve placement guidewires to the aortic annulus or other target location.

[0016] In a third aspect, the present invention provides an embolic filter positioning system comprising: (1) a vascular delivery sheath having a proximal hemostatic valve, an open distal end, and an open lumen extending from the open distal end to the hemostatic valve, (2) a filter catheter having proximal and distal ends and a central lumen therethrough, (3) a self-expanding embolic filter attached to the distal end of the filter catheter, (4) an elongated dilator having proximal and distal ends and a guidewire lumen therethrough, and (5) a tapered dilator tip attached to the distal end of the elongated dilator, wherein the elongated dilator is configured to be slidably received within the central lumen of the filter catheter, and the filter catheter is configured to be slidably received within the open lumen of the vascular delivery sheath. The tapered dilator tip is positionable distal to the distal end of the vascular delivery sheath, and the self-expanding embolic filter is configured to be radially constrained in the proximal portion of the open lumen of the vascular delivery sheath. The tapered dilator tip has an expanded configuration in which it covers the open distal end of the vascular delivery sheath and facilitates entry through the arteriotomy, and a contracted configuration in which it can be retracted through the central lumen of the filter catheter.

[0017] In some embodiments of the embolic filter positioning system of the present invention, the tapered dilator tip may have a conical geometry and a base configured to removably mate with the open distal end of the vascular delivery sheath. In certain cases, the base of the tapered dilator tip may be cylindrical and configured to fit inside the open distal end of the vascular delivery sheath.

[0018] In other embodiments, the embolic filter positioning system of the present invention may further comprise a handle attached to the proximal end of the filter catheter. In certain cases, the handle may comprise a mechanism for closing the proximal end of the embolic filter prior to retracting the filter back into the vascular delivery sheath, for example, the mechanism for closing the proximal end of the embolic filter may comprise a ratchet retractor coupled to a loop on the proximal end of the embolic filter.

[0019] In some embodiments of the embolic filter positioning system of the present invention, the embolic filter may comprise a cylindrical body configured to self-expand and conform to the inner wall of the patient's aortic arch. In certain cases, the embolic filter may further comprise a port extending across the central passage of the cylindrical body, the port being expandable and configured to seal against the outer surface of catheters and guidewires advanced therethrough. In other cases, the cylindrical body of the embolic filter may comprise a porous material comprising a knitted, woven, or non-woven fibrous fabric, filament, or wire. For example, the porous material may be made from a resilient metal, a polymeric material, a malleable material, a plastically deformable material, a shape-memory material, or a combination thereof. In other embodiments, the porous material may have a pore size selected to prevent emboli above a predetermined size from passing therethrough. The present invention provides, for example, the following. (Item 1) 1. A method of positioning an embolic filter in an aortic arch of a patient, the method comprising: (2) a filter catheter slidably received within an open lumen of the vascular delivery sheath; (3) an elongate dilator having a guidewire lumen slidably received within a central lumen of the filter catheter; (4) a tapered dilator tip attached to a distal end of the elongate dilator; and (5) an embolic filter carried on a distal portion of the filter catheter; expanding and positioning the tapered dilator tip to extend distally beyond and cover the open distal end of the vascular delivery sheath; introducing the expanded tapered dilator tip of the embolic filter positioning assembly through an arteriotomy over a first guidewire received within the guidewire lumen of the elongate dilator and into the patient's arterial vasculature; advancing the distal end of the embolic filter positioning assembly to position the embolic filter carried on the distal portion of the filter catheter within the patient's aortic arch; retracting a distal portion of the vascular delivery sheath from over the embolic filter to expand the embolic filter within the patient's aortic arch; contracting the tapered dilator tip and retracting the tip proximally into or through the central lumen of the filter catheter; A method comprising: (Item 2) Item 14. The method of item 1, wherein expanding the tapered dilator tip comprises expanding the tapered dilator tip and contracting the tapered dilator tip comprises deflating the tapered dilator tip. (Item 3) 3. The method of claim 1, wherein the tapered dilator tip has a conical geometry with a base, and wherein positioning the tapered dilator tip to extend distally beyond and cover the open distal end of the vascular delivery sheath comprises removably mating the base with the open distal end of the vascular delivery sheath. (Item 4) Item 4. The method of item 3, wherein the base of the tapered dilator tip is cylindrical and configured to fit inside the open distal end of the vascular delivery sheath. (Item 5) 5. The method of claim 1, further comprising closing the proximal end of the embolic filter and retracting the filter back into the vascular delivery sheath. (Item 6) Item 6. The method of item 5, wherein closing the proximal end of the embolic filter comprises tightening a loop on the proximal end of the embolic filter. (Item 7) 7. The method of claim 1, wherein the embolic filter self-expands within the patient's aortic arch after the distal portion of the vascular sheath is retracted from over the embolic filter. (Item 8) 1. A method for implanting a prosthetic aortic valve in a patient, the method comprising: placing an embolic filter in the aortic arch of the patient as described in any one of items 1-7; advancing the prosthetic aortic valve through the embolic filter; deploying the prosthetic aortic valve within the aortic annulus of the patient while the embolic filter remains in place within the aortic arch; A method comprising: (Item 9) Advancing the prosthetic aortic valve through the embolic filter comprises: removing the elongate dilator from the central lumen of the filter catheter, leaving the first guidewire in place within the central lumen of the filter catheter; exchanging the first guidewire for an angiography pigtail catheter; advancing one or more valve placement guidewires through the embolic filter and parallel to the embolic filter positioning assembly across the aortic arch; advancing a valve placement catheter carrying the prosthetic valve over the one or more valve placement guidewires; Item 9. The method according to item 8, comprising: (Item 10) 1. An embolic filter positioning system comprising: a vascular delivery sheath having a proximal hemostatic valve, an open distal end, and an open lumen extending from said open distal end to said hemostatic valve; a filter catheter having a proximal end, a distal end, and a central lumen therethrough; a self-expanding embolic filter attached to the distal end of the filter catheter; an elongate dilator having a proximal end, a distal end, and a guidewire lumen therethrough; a tapered dilator tip attached to the distal end of the elongate dilator; Equipped with the elongated dilator is configured to be slidably received within the central lumen of the filter catheter, the filter catheter is configured to be slidably received within the open lumen of the vascular delivery sheath, the tapered dilator tip is positionable distally of the distal end of the vascular delivery sheath, and the self-expanding embolic filter is configured to be radially constrained in a proximal portion of the open lumen of the vascular delivery sheath; the tapered dilator tip has an expanded configuration in which it covers the open distal end of the vascular delivery sheath and facilitates entry through an arteriotomy, and a contracted configuration in which it may be retracted through the central lumen of the filter catheter. Embolic filter positioning system. (Item 11) Item 11. The embolic filter positioning system of item 10, wherein the tapered dilator tip has a conical geometry and a base configured to removably mate with the open distal end of the vascular delivery sheath. (Item 12) Item 12. The embolic filter positioning system of item 11, wherein the base of the tapered dilator tip is cylindrical and configured to fit inside the open distal end of the vascular delivery sheath. (Item 13) 13. The embolic filter positioning system of items 10-12, further comprising a handle attached to the proximal end of the filter catheter. (Item 14) Item 14. The embolic filter positioning system of item 13, wherein the handle comprises a mechanism for closing the proximal end of the embolic filter prior to retracting the filter back into the vascular delivery sheath. (Item 15) Item 15. The embolic filter positioning system of item 14, wherein the mechanism for closing the proximal end of the embolic filter comprises a ratchet retractor coupled to a loop on the proximal end of the embolic filter. (Item 16) 16. The embolic filter positioning system of items 10-15, wherein the embolic filter comprises a cylindrical body configured to self-expand within and conform to the inner wall of the patient's aortic arch. (Item 17) Item 17. The embolic filter positioning system of item 16, wherein the embolic filter further comprises a port extending across the central passage of the cylindrical body, the port being expandable and configured to seal against the outer surface of catheters and guidewires advanced therethrough. (Item 18) Item 18. The embolic filter positioning system of item 16 or 17, wherein the cylindrical body comprises a porous material comprising a knitted, woven, or non-woven fibrous fabric, filaments, or wires. (Item 19) Item 19. The embolic filter positioning system of item 18, wherein the porous material is made from a resilient metal, a polymeric material, a malleable material, a plastically deformable material, a shape memory material, or a combination thereof. (Item 20) 20. The embolic filter positioning system of claim 18 or 19, wherein the porous material has a pore size selected to prevent emboli exceeding a predetermined size from passing therethrough.

[0020] (Incorporated by reference) All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. [Brief explanation of the drawings]

[0021] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings, in which:

[0022] [Figure 1] FIG. 1 shows a prior art endovascular sheath having a conventional solid dilator with a guidewire extending distally from the lumen of the dilator.

[0023] [Figure 2A] 2A-2C show the distal portion of a vascular delivery sheath according to the present invention, with the balloon dilator in an uninflated state in FIG. 2A, the balloon dilator in an inflated state in FIG. 2B, and the inflated balloon dilator retracted proximally into the distal tip of the sheath in FIG. 2C. [Figure 2B]2A-2C show the distal portion of a vascular delivery sheath according to the present invention, with the balloon dilator in an uninflated state in FIG. 2A, the balloon dilator in an inflated state in FIG. 2B, and the inflated balloon dilator retracted proximally into the distal tip of the sheath in FIG. 2C. [Figure 2C] 2A-2C show the distal portion of a vascular delivery sheath according to the present invention, with the balloon dilator in an uninflated state in FIG. 2A, the balloon dilator in an inflated state in FIG. 2B, and the inflated balloon dilator retracted proximally into the distal tip of the sheath in FIG. 2C.

[0024] [Figure 3] FIG. 3 shows the full-length sheath of FIGS. 2A-2C, including a hemostatic valve at its proximal end, without a dilator.

[0025] [Figure 4] FIG. 4 shows a full-length dilator of the vascular delivery sheath of FIGS. 2A-2C, including the proximal hub.

[0026] [Figure 5] FIG. 5 shows a filter catheter according to the present invention, having an embolic filter at its distal end and a handle at its proximal end.

[0027] [Figure 6] FIG. 6 is a detailed cutaway view showing an embolic filter attached to the distal end of a filter catheter shaft, with a vascular delivery sheath assembly positioned therethrough, and the expandable tip in its uninflated configuration.

[0028] [Figure 7] FIG. 7 is a detailed view capturing the expandable tip of the dilator of the vascular delivery sheath assembly in its expanded configuration extending from the distal end of the vascular delivery sheath.

[0029] [Figure 8] FIG. 8 is a detailed view similar to that of FIG. 7, showing the expanded tip of the dilator being withdrawn into the open end of the vascular delivery sheath proximally relative to the patient's femoral artery.

[0030] [Figure 9A] 9A-9F illustrate the use of a vascular delivery sheath assembly of the present invention to place an embolic filter within a patient's aortic arch and subsequently implant a prosthetic valve within the patient's aortic annulus. [Figure 9B] 9A-9F illustrate the use of a vascular delivery sheath assembly of the present invention to place an embolic filter within a patient's aortic arch and subsequently implant a prosthetic valve within the patient's aortic annulus. [Figure 9C] 9A-9F illustrate the use of a vascular delivery sheath assembly of the present invention to place an embolic filter within a patient's aortic arch and subsequently implant a prosthetic valve within the patient's aortic annulus. [Figure 9D] 9A-9F illustrate the use of a vascular delivery sheath assembly of the present invention to place an embolic filter within a patient's aortic arch and subsequently implant a prosthetic valve within the patient's aortic annulus. [Figure 9E] 9A-9F illustrate the use of a vascular delivery sheath assembly of the present invention to place an embolic filter within a patient's aortic arch and subsequently implant a prosthetic valve within the patient's aortic annulus. [Figure 9F] 9A-9F illustrate the use of a vascular delivery sheath assembly of the present invention to place an embolic filter within a patient's aortic arch and subsequently implant a prosthetic valve within the patient's aortic annulus.

[0031] [Figure 10A] 10A and 10B illustrate the use of a ratchet mechanism to close the ends of the embolic filter prior to retracting the filter back into the delivery sheath. [Figure 10B] 10A and 10B illustrate the use of a ratchet mechanism to close the ends of the embolic filter prior to retracting the filter back into the delivery sheath. DETAILED DESCRIPTION OF THE INVENTION

[0032] Detailed Description of the Invention For purposes of this patent application, the term "distal" refers to the end of the device furthest away from the operator and closest to the heart. This is also the "upstream" direction of blood flow. The term "proximal" refers to the end of the device closer to the operator and furthest away from the heart, toward the access site where the device is introduced into the body. This is also the "downstream" direction of blood flow.

[0033] In the present invention, conventional dilators are replaced with "expandable tip catheters," typically "balloon dilators," that have a distal taper similar in profile to the tapered tip of conventional dilators and are attached to a smaller diameter shaft with a guidewire lumen for accommodating a guidewire, with an additional lumen to facilitate balloon inflation and de-inflation. This structure may resemble a non-distensible balloon catheter used for angioplasty, with the shape of the balloon optimized to facilitate its use as a dilator, typically tapered conically with narrow ends facing distally.

[0034] A primary advantage of the balloon or other expandable dilator of the present invention is that an associated interventional or diagnostic catheter can be placed through the sheath and over the shaft of the balloon dilator (i.e., and thus over a guidewire) without the need for removal of the balloon dilator. In preferred embodiments, the interventional or diagnostic device can be preloaded over the balloon dilator within the sheath, saving procedure time and improving ease of use of the device, which no longer requires an initial introduction step through the proximal end of the sheath.

[0035] As an example, an embolic protection filter, which may be made from a self-expanding material (e.g., a shape memory alloy), can be compressed and preloaded over the shaft of a balloon dilator and into the distal end of a sheath. The balloon dilator can then be withdrawn until the balloon itself is located at the distal end of the sheath. The balloon can then be inflated to create a somewhat rigid distal taper that mates with the end of the sheath. The entire system can then be introduced over a guidewire through the Seldinger puncture and advanced to the treatment site. The sheath is then withdrawn from around the filter, allowing the filter to expand in place. After filter deployment, the balloon is deinflated, and the entire balloon dilator system is withdrawn and removed through the lumen of the filter and attachment catheter, leaving the sheath, filter, and guidewire behind.

[0036] The tapered balloon of the present invention may also be replaced with a mechanically expandable frame with a polymer coating, or any other expandable and contractible system that acts as a temporary dilator tip during insertion of a sheath through the Selzinger puncture.

[0037] Some delivery systems use a nose cone, or olive, at the distal end that replaces the traditional dilator and allows the device to be loaded over a smaller shaft at the distal end. In these cases, the olive can either be tightly mated to the ID of the sheath (allowing it to be removed through the sheath) or matched to the OD of the sheath, preventing its removal from the sheath. In the balloon dilator of the present invention, the diameter of the inflated balloon is matched to the diameter of the sheath, but because the balloon is foldable, it can still be removed, providing greater flexibility for the delivery or passage of other interventional devices.

[0038] Additionally, as interventional procedures and devices increase in complexity, multi-catheter systems may be required for their delivery into the body. One example is a system consisting of four catheters, where each catheter has a distinct function while being capable of being introduced through a single arteriotomy. The first (outermost) catheter acts as a vehicle for intravascular access and removal of two additional devices. The second catheter is attached to or carries either a therapeutic or prophylactic device. A third balloon dilator catheter passes through the second catheter to allow insertion through the arteriotomy. Eventually, a diagnostic catheter replaces the balloon dilator catheter, leaving three catheters with distinct functions in a single arteriotomy. Any fixed diameter dilator, nose cone, or olive that is matched to the diameter of the outer catheter (as opposed to a collapsible balloon dilator) for use in crossing an arteriotomy would therefore be too large to be removed through a second catheter and would therefore require a second puncture / access site for placement of the diagnostic catheter.

[0039] 2A-2C, 3, and 4, a vascular delivery sheath assembly 20 according to the present invention comprises a vascular delivery sheath 22 having an open distal end 24, a proximal end 26 (FIG. 3), and a lumen 28 therethrough. A dilator 30 comprises a shaft 32 having a distal end 34 and a proximal end (not shown), and an expandable tip 38 at its distal end. The expandable tip 38 is shown in its unexpanded state in FIG. 2A. The tip 38 is shaped to expand into a tapered profile, typically a conical profile, as shown in FIG. 2B. The conical configuration includes a narrow or pointed distal end 40 and a cylindrical base 42 at its proximal end. As shown in FIG. 2C, the dilator shaft 32 can be pulled proximally to retract the base 42 into the distal opening 24 of the vascular delivery sheath 22. 2C, the vascular delivery sheath assembly 20 is ready for introduction over a guidewire 44 and for use in a vascular procedure of the present invention, as described more fully below. The sheath 22 typically includes a hemostatic valve 46, which may include a side port 48 for introducing contrast media or for other purposes. The dilator 30 has a guidewire lumen (not shown) and typically includes a hub 50 with a hemostatic port 52 for receiving the guidewire 44 and an inflation port 54 for inflating the expandable tip 38.

[0040] 5 , the filter catheter 60 includes a shaft 62 having a distal end 64 and a proximal end 66. The shaft 62 will be sized to fit within the lumen of the vascular delivery sheath 22, as will be described in more detail below. The shaft 62 will typically itself include a lumen or central passageway for connecting a purse string suture loop 78 at the distal end 64 to a handle 70 at the proximal end 66. An embolic filter 68, typically a self-expanding cylindrical mesh filter of the type described in commonly owned U.S. Patent Publication No. 2020 / 0253709 (the full disclosure of which is incorporated herein by reference), is secured to the distal end 64 of the shaft 62, typically by the purse string suture loop 78. The handle 70 typically includes a side port 72 and a ratchet pull 76 configured to receive the dilator 30 and / or an associated guidewire. The ratchet pull is configured to "cinch" as shown in Figures 10A and 10B, applying proximal tension on the purse string suture 78 to close the proximal end of the embolic filter as shown in Figure 10B.

[0041] 6 , to prepare the vascular delivery sheath assembly 20 for introduction into a patient, the dilator 30 is first introduced through the lumen of the shaft 62 so that it extends through the interior of the embolic filter 68. The dilator 30 and filter catheter 60 subassembly is then advanced into the vascular delivery sheath 22 so that they both extend beyond the distal open end 24 of the sheath 22.

[0042] 7 and 8, the vascular delivery sheath assembly 24 is further prepared by retracting the embolic filter 68 through the open end 24 of the sheath 22 so that it is elongated and radially constrained. The expandable tip 38 of the dilator 30 is then expanded to assume its tapered configuration. The expandable tip 38 is typically formed from a non-distensible material such as polyethylene terephthalate (PET), nylon, or other materials of the type used in fabricating angioplasty balloons. The expandable tip will be inflated with an incompressible fluid, typically saline, to a pressure sufficient to form a rigid body suitable for advancement into the femoral artery and through the patient's vasculature. Thus, during use, the expandable tip will perform in a manner similar to a conventional solid-tip dilator.

[0043] After the expandable tip 38 is expanded, it can be retracted into the open end 24 of the vascular delivery sheath 22. When expanded, the expandable tip 38 typically has a generally conical shape with a pointed tip 40 and a cylindrical base 42 sized and configured to mate with the open end 24 of the sheath, as shown in FIG. 8, and the dilator is retracted proximally within the sheath.

[0044] 9A-9F, the use of the vascular delivery sheath assembly 20 to place an embolic filter 68 within a patient's aortic arch AA will be described. With the distal region of the vascular delivery sheath assembly 20 in the configuration shown in FIGS. 2C and 8, the expandable tip 38 is introduced over a guidewire 44 through a femoral access site FAS. The expanded tip 38 acts in the same manner as a conventional solid dilator at this stage of the intervention. The expanded tip 38 and vascular delivery sheath 22 are then advanced across the patient's aortic arch AA, as shown in FIG. 9B.

[0045] After the distal portion of the vascular delivery sheath assembly 20 has crossed the aortic arch AA and reached the target location, the delivery sheath 22 would be retracted to deploy the embolic filter 68, as shown in FIG. 9C. Recoil may be achieved by pulling proximally on the hemostatic valve 46 at the proximal end of the sheath 22 and pulling the sheath back over the shaft 62 of the filter catheter 60, allowing the filter to self-expand. After the embolic filter has been deployed, the expandable tip 38 may be de-inflated and retracted proximally back into the lumen 28 of the sheath 22. Typically, the entire dilator 30 would be removed from the sheath 22 at this point.

[0046] With the embolic filter 68, possibly deployed, a separate guidewire GW can be introduced across the aortic arch AA and through the filter, as shown in FIG. 9E, and a delivery catheter 92 can be advanced over the guidewire GW. The delivery catheter 92 may be used to deliver any conventional prosthetic aortic valve, typically a balloon-expandable aortic valve such as the Edwards Sapien® valve or the Medtronic CoreValve® heart. Details of how the valve can be introduced through the embolic filter 68 are provided in commonly owned U.S. Patent Publication No. 2020 / 0253709, the full disclosure of which has been previously incorporated by reference herein.

[0047] After the prosthetic aortic valve 90 has been properly implanted, the valve delivery catheter 90 may be removed, followed by removal of the embolic filter 68, as shown in Figure 9F. Typically, a ratchet pull 76 on the filter catheter handle 70 is used to retract a purse string suture loop 78 on the filter downwardly, prior to retracting proximally on the filter catheter to pull the filter 68 into the open end 24 of the sheath 22, as shown in Figures 10A and 10B.

[0048] While preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It is understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. The following claims define the scope of the invention, and it is intended that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

1. A multiple catheter positioning system for use through a single arterial incision, A first outermost vascular delivery sheath having a proximal hemostatic valve, an open distal end, and an open lumen extending from the open distal end to the hemostatic valve, A second catheter having a proximal end, a distal end, and a central lumen through which it passes, the second catheter being attached to or transporting either a therapeutic or preventive device, A third balloon dilator catheter, the third balloon dilator catheter having a proximal end, a tapered dilator tip, and a guidewire lumen through which it passes. Equipped with, The third balloon dilator catheter is configured to be slidably received within the central lumen of the second catheter, the second catheter is configured to be slidably received within the open lumen of the first outermost vascular delivery sheath, the tapered dilator tip is positionable distal to the distal end of the first outermost vascular delivery sheath, and the therapeutic or prophylactic device is fitted and configured to deploy after inflation and deinflation of the tapered dilator tip of the third balloon dilator catheter. A multi-catheter positioning system wherein the tapered dilator tip has an expanded configuration that covers the distal opening end of the first outermost vascular delivery sheath and facilitates entry through the single arterial incision, and a contracted configuration that can be retracted through the central lumen of the second catheter.

2. The positioning system for multiple catheters according to claim 1, wherein the tip of the tapered dilator has a conical geometric shape with a base configured to removably interlock with the distal opening end of the first outermost vascular delivery sheath.

3. The positioning system for multiple catheters according to claim 2, wherein the base of the tapered dilator tip is cylindrical and configured to fit inside the distal opening of the first outermost vascular delivery sheath.

4. The positioning system for multiple catheters according to claims 1 to 3, further comprising a handle attached to the proximal end of the second catheter.

5. The multiple catheter positioning system according to claim 4, wherein the handle comprises a mechanism for retracting the therapeutic or preventive device into the first outermost vascular delivery sheath.

6. The plurality catheter positioning system according to claim 5, wherein the mechanism comprises a ratchet retractor coupled to the ring-shaped portion.

7. The multiple catheter positioning system according to claims 1 to 6, further comprising an embolization filter, the embolization filter comprising a cylindrical body, the cylindrical body being configured to self-expand within the inner wall of the patient's aortic arch and conform to the inner wall.

8. The multiple catheter positioning system according to claim 7, further comprising a port extending across the central passage of the cylindrical body, the port being expandable and configured to seal against the outer surfaces of catheters and guidewires advanced through it.

9. The multiple catheter positioning system according to claims 7 to 8, wherein the cylindrical body comprises a porous material, the porous material comprising a knitted, woven or unwoven fiber fabric, filament or wire.

10. The multiple catheter positioning system according to claim 9, wherein the porous material is made from an elastic metal, a polymer material, a malleable material, a plastically deformable material, a shape memory material, or a combination thereof.

11. The multiple catheter positioning system according to claims 9 to 10, wherein the porous material has a pore size selected to prevent embolus exceeding a predetermined size from passing through it.

Images