Guide catheter for flow modification device

Abstract

A system for implanting a flow modification device in the heart includes a flow modification device comprising a tubular body having first and second openings located at first and second ends of the tubular body and a reduced diameter section positioned between the first and second openings, and a guide catheter having a flexible elongate shaft having a proximal portion with a coupling for receiving an insertion tool and a distal portion with an enlarged distal tip for preventing the flexible elongate shaft from passing through the flow modification device. A guide catheter for cannulating the coronary sinus from the superior vena cava includes a pre-shaped distal portion with a proximal straight zone, a proximal curved zone extending along a first curved path, a distal straight zone extending along a straight path, and a distal curved zone extending along a second curved path. The guide catheter can have different stiffnesses.

Description

[Technical Field]

[0001] This document relates generally, but not exclusively, to elongated surgical instruments configured to be inserted into anatomical vessels to deliver medical devices to specific internal anatomical locations. More particularly, but not exclusively, this application relates to guide catheters that can be used to deliver flow modification devices to the heart. [Background technology]

[0002] The heart pumps blood throughout the body. The heart itself is pumped by coronary arteries, which terminate in capillaries. The capillaries are typically drained by a network of coronary veins that drain into a vein known as the coronary sinus. The coronary sinus is a short, large-diameter vein that is substantially continuous with the right atrium, the atrium that collects all venous blood from the body.

[0003] Blockage of coronary arteries is a leading cause of death, particularly sudden death, commonly referred to as a "heart attack." When blood flow to a portion of the heart is suddenly stopped, that portion becomes ischemic and its electrical activity is disrupted. Because cardiac activity is mediated by electrical signal propagation, such disruption typically propagates to the rest of the heart, disrupting cardiac activation and, in some cases, significantly reducing cardiac output, which can lead to ischemia and brain death. In addition, the unregulated activity often damages the heart more than is directly caused by the blockage.

[0004] If a patient survives the immediate effects of a heart attack, damage to the heart may predispose the patient to future electrical disorders or may significantly reduce cardiac output, thus reducing quality of life and life expectancy.

[0005] Angina pectoris is a chronic or semi-chronic condition that, while not life-threatening, significantly reduces quality of life. Generally, the heart responds to increased demand by working harder and demanding more coronary blood flow. When the coronary arteries are narrowed or blocked, the increased blood flow cannot be provided, and pain caused by the resulting ischemia is produced.

[0006] The heart has natural mechanisms for overcoming stenosis in the coronary arteries. One such mechanism is angiogenesis, in which new arteries are generated to bypass the stenosis.

[0007] Because angiogenesis sometimes does not occur naturally, various procedures have been proposed to stimulate it, such as transmyocardial revascularization (TMR), a process in which multiple holes are drilled into the heart with the intention of generating new blood vessels.

[0008] Beck, in "The Surgical Management of Coronary Artery Disease: Background, Rationale, Clinical Experience" by C.S.Beck and B.L. Brofman, October 10, 1956, by the American College of Physicians in Annals of Internal Medicine, Vol. 45, No. 6, December 1956, and "Long Term Influence of the Beck Operation for Coronary Heart Disease," by B.L. Brofman in the American Journal of Cardiology, August 1960 (the disclosures of which are incorporated herein by reference), performed an open-chest surgery in which the coronary sinus veins were restricted with external sutures. After several months, coronary artery blood supply apparently improved. However, this procedure has fallen out of favor, perhaps in part due to the need to open the chest, lift the heart, and access the coronary sinus veins.

[0009] The standard treatment for a stenosed artery is to insert a stent into the artery at the point of narrowing. The stent, e.g., a metal coil or mesh, is expanded to have an inner diameter similar to that of the original narrowed blood vessel. When there are many or elongated stenoses, it is not common to implant multiple stents. Instead, a bypass procedure is performed, in which a conduit is used to bypass the stenosis.

[0010] U.S. Patent No. 5,618,301 (the disclosure of which is incorporated herein by reference) describes a stent-like device for reducing the diameter of a body conduit. Described is an open mesh stent that can be inserted into a channel created by a TIPS (transjugular intrahepatic portosystemic shunt) procedure to reduce blood flow through the channel, ensuring that the flow diameter is reduced and preventing flow through the open mesh; multiple thrombogenic threads are provided on the outside of the mesh. However, as can be appreciated, intentionally forming a thrombus in almost any part of the vascular system, especially near the heart, can lead to the propagation of clots or floating thrombi, which can be potentially fatal.

[0011] Delivery of such stents and stent-like devices to various anatomical regions of the heart can be complicated. Typically, a guide catheter comprising a long, thin, flexible tube can be used to reach the target tissue where the stent or stent-like device is to be deployed. A delivery device can then be inserted into the guide catheter to position the stent or stent-like device at the target tissue. The guide catheter can be pre-curved to facilitate reaching the target tissue. Johnson Patent No. US 7,556,625 B2 discloses a "coronary sinus lead delivery catheter." [Prior art documents] [Patent documents]

[0012] [Patent Document 1] U.S. Patent No. 5,618,301 [Non-patent literature]

[0013] [Non-Patent Document 1] CSBeck, BLBrofman “The Surgical Management of Coronary Artery Disease:Background,Rationale,Clinical Experience”,American College of Physicians in Annals of Internal Medicine Vol.45,No.6,December 1956 Summary of the Invention [Means for solving the problem]

[0014] The inventors have recognized, among other things, that problems to be solved with guide catheters include the difficulty that catheters have in retaining their position within the anatomy once inserted into a desired location to reach a target tissue. For example, some guide catheters are pre-shaped to facilitate navigation and positioning within a particular anatomy. However, when another insertion instrument (such as a delivery catheter for deploying an expandable flow modification device) is inserted through the guide catheter, the tip of the guide catheter may lose its position within the anatomy, thereby becoming separated from the target tissue and making it more difficult to position the flow modification device at the desired location.

[0015] The present subject matter can provide solutions to this and other problems, such as by providing a pre-shaped guide catheter that can better maintain its position within the anatomy while receiving a delivery catheter therethrough. The pre-shaped catheter can include proximal and distal curved zones, with a straight zone located therebetween. Such a pre-shaped catheter can better push through anatomy, such as the coronary sinus, while receiving a delivery catheter.

[0016] The inventors recognize that expandable and implantable medical devices are often inserted and deployed using generic, off-the-shelf instrumentation, such as insertion and guide catheters designed to work with a wide variety of medical devices. The inventors recognize that compatibility of generic implantation instrumentation with specific medical devices can lead to difficulties in the implantation procedure, which can sometimes affect the outcome. For example, sometimes the relative sizing of the guide catheter can result in the guide catheter being undesirably inserted into the medical device, or difficulty in retracting the deployment balloon back into the guide catheter. These issues can lead to difficulties in placing and shaping the implantable medical device.

[0017] The present subject matter can provide solutions to these and other problems by providing implantation instrumentation, such as guide catheters, that are specifically shaped and sized to function with specific implantable medical devices. For example, the present disclosure describes guide catheters with shaped tips designed to engage in a specific manner with specific implantable medical devices, such as flow modification devices. The shaped tips can be enlarged relative to the shaft of the guide catheter to prevent the guide catheter from passing through the implantable medical device. The shaped tips can engage the implantable medical device in a close-fitting manner through a larger surface area compared to just the tip of a cylindrical tube to prevent damaging or otherwise deforming the implantable medical device. Furthermore, the shaped tips can be shaped to facilitate re-entry of devices deployed therefrom, such as deployment balloons. The enlarged and shaped tips allow the shaft of the guide catheter to remain small and flexible. Thus, the present disclosure describes a system of implantable medical devices and implantation instruments that function specifically together to improve procedural outcomes, e.g., to implant medical devices in precise locations, with precise shapes, in less time, and with less difficulty.

[0018] The inventors have recognized that, among other issues, problems to be solved with guide catheters include difficulties in balancing the ability to insert and bend the guide catheter while positioned within the anatomy with the guide catheter's ability to receive other instruments. For example, a thin or small-diameter guide catheter, such as an 8 French (approximately 2.67 mm) diameter, can be easily bent but cannot receive large insertion instruments. Furthermore, smaller guide catheters can lead to difficulties in retracting an insertion instrument back into the guide catheter. For example, the balloon of the insertion instrument sometimes does not completely collapse to its pre-inflation size, thereby making retrieval of the balloon back into the guide catheter difficult. Furthermore, when attempting to retract a device into the guide catheter, the guide catheter may be pushed forward due to poking by the guide catheter or the like, resulting in the deployed device becoming lodged.

[0019] The present subject matter can provide a solution to this and other problems, such as by providing a guide catheter with an enlarged tip. In various examples, the enlarged tip can, for example, guide a funnel insertion tool back into the guide catheter, preventing the guide catheter from undesirably engaging a deployed device. Additionally, in various examples, the enlarged tip can prevent the guide catheter from being pushed inside the deployed or implanted device. The enlarged tip can be located only at the distal end of an elongated guide catheter so that the main shaft of the guide catheter can be small and flexible, such as for intravascular use.

[0020] The inventors have recognized that, among other things, problems to be solved regarding guide catheters include difficulties in determining the orientation of a pre-curved guide catheter once inserted into the anatomy. For example, a pre-curved guide catheter is intended to be placed in a specific orientation within a curved anatomy so that the curvature of the guide catheter matches the path of the anatomy. However, the pre-curve of the guide catheter may become distorted while being inserted through the anatomy, particularly as the guide catheter is rotated and poked during the insertion process. Thus, the guide catheter may become twisted, and the pre-curve may become misaligned with the anatomy. Thus, the guide catheter may become stressed and have an undesirable curvature introduced therein. Furthermore, a surgeon may not know the direction in which the pre-curve of the guide catheter is pointing, which may interfere with the delivery of a device using an inserter catheter inserted into the guide catheter.

[0021] The present subject matter can provide a solution to this and other problems, such as by providing markings on the proximal end portion of the guide catheter. The markings can indicate the direction in which the distal portion of the guide catheter is curved. Additionally, the markings can indicate the plane in which the distal portion is curved, informing the surgeon as to the direction in which the distal portion is biased. The surgeon can use the markings to orient the guide catheter so that the pre-curve better aligns with the anatomy, thereby better preparing to deliver a device using the guide catheter.

[0022] In one example, a guide catheter for cannulating the coronary sinus through the superior vena cava can include a flexible elongate shaft having a proximal portion, a pre-shaped distal portion including a proximal straight zone, a proximal curved zone extending from the proximal straight zone along a first curved path, a distal straight zone extending from the proximal curved zone along a straight path, and a distal curved zone extending from the distal straight zone along a second curved path, and a distal tip extending from the distal curved zone.

[0023] In another example, a guide catheter for delivering an expandable flow modification device to a cardiac passageway can include a flexible elongate shaft having a proximal portion with a coupling for receiving an insertion tool and a distal portion with a distal tip, the distal tip including an enlarged tip to prevent the flexible elongate shaft from passing through the expandable flow modification device.

[0024] In an additional example, a system for implanting a flow modification device in the cardiac vasculature can include a flow modification device and a guide catheter. The flow modification device can include a tubular body having a first opening located at a first end of the tubular body, a second opening located at a second end of the tubular body, and a reduced diameter portion positioned between the first and second openings. The guide catheter can include a flexible elongate shaft having a proximal portion including a coupling for receiving an insertion tool and a distal portion including a distal tip, the distal tip including an enlarged tip to prevent passage of the flexible elongate shaft through the flow modification device.

[0025] This Summary is intended to provide an overview of the subject matter of this patent application. It is not intended to provide an exclusive or comprehensive description of the invention. The Detailed Description is included to provide further information about this patent application. [Brief explanation of the drawings]

[0026] [Figure 1A] FIG. 1A is a side view of a guide catheter of the present disclosure in an artificially straightened configuration, illustrating different stiffness sections of the flexible elongate shaft.

[0027] [Figure 1B] FIG. 1B is a side view of the guide catheter of FIG. 1A in a pre-curved state.

[0028] [Figure 2] FIG. 2 is an enlarged side view of the distal end portion of the guide catheter of FIG. 1B, showing multiple curvature zones with pre-curves.

[0029] [Figure 3] FIG. 3 is a schematic diagram of a portion of the guide catheter of FIGS. 1A and 1B, showing the various layers that form the guide catheter.

[0030] [Figure 4A] FIG. 4A is a schematic diagram of the human heart and associated vasculature with a guide catheter inserted therein.

[0031] [Figure 4B] FIG. 4B is a schematic illustration of a guide catheter of the present disclosure inserted into the coronary sinus of a human heart.

[0032] [Figure 5A] FIG. 5A is a schematic diagram showing a guide catheter with an inserter inserted to expand a flow modification device with a balloon.

[0033] [Figure 5B] FIG. 5B is a schematic diagram showing the guide catheter of FIG. 5A extended into a flow modification device and an insertion tool withdrawn therefrom.

[0034] [Figure 6A] FIG. 6A is a perspective view of the proximal end of a guide catheter of the present disclosure including a fitting having a pre-curve marking located thereon.

[0035] [Figure 6B] FIG. 6B is a side view of the coupling of FIG. 6A showing a pair of wings extending from the coupler.

[0036] [Figure 6C] FIG. 6C is an end view of the joint of FIG. 6A showing markings located on either side of one of the wings.

[0037] [Figure 7A] FIG. 7A is a perspective view of the distal end of a guide catheter of the present disclosure having a flared tip.

[0038] [Figure 7B] FIG. 7B is a side view of the distal end of FIG. 7A showing the flared tip.

[0039] [Figure 7C] FIG. 7C is a perspective view of the distal end of the guide catheter of FIG. 7A protruding from the containment sheath.

[0040] [Figure 7D] FIG. 7D is a side view of the flared tip of the guide catheter of FIGS. 7A-7C engaged with a flow modification device.

[0041] [Figure 8A] FIG. 8A is a perspective view of the distal end of a guide catheter of the present disclosure equipped with an escape tip.

[0042] [Figure 8B] FIG. 8B is a side view of the distal end of FIG. 8A showing the prolapse tip.

[0043] [Figure 8C] FIG. 8C is a side cross-sectional view of the guide catheter of FIG. 8B showing the deflected shape of the prolapse tip.

[0044] [Figure 8D] FIG. 8D is a side view of the prolapse tip of the guide catheter of FIGS. 8A-8C engaged with a flow modification device.

[0045] [Figure 9A] FIG. 9A is a perspective view of the distal end of a guide catheter of the present disclosure equipped with a balloon tip.

[0046] [Figure 9B] FIG. 9B is a side view of the distal end of FIG. 9A showing the balloon tip.

[0047] [Figure 9C] FIG. 9C is a side cross-sectional view of the guide catheter of FIG. 9B showing the inflatable bladder at the balloon tip.

[0048] [Figure 9D] FIG. 9D is a side view of the balloon tip of the guide catheter of FIGS. 9A-9C engaged with a flow modification device.

[0049] [Figure 10] FIG. 10 is a side view of the distal end of a guide catheter of the present disclosure having a funnel-shaped tip.

[0050] [Figure 11] FIG. 11 is a diagram illustrating operations of a method of implanting a flow modification device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0051] In the drawings, which are not necessarily drawn to scale, like numbers may describe similar components in different figures. Like numbers with different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0052] FIG. 1A is a side view of a guide catheter 100 of the present disclosure in an artificially straightened configuration to illustrate different stiffness sections of the flexible elongate shaft. FIG. 1B is a side view of the guide catheter 100 of FIG. 1A in a pre-curved state illustrating multiple curvature zones having pre-curves. Thus, FIG. 1B illustrates the guide catheter 100 at rest with no applied force, while FIG. 1A illustrates a theoretical straightening force applied to the guide catheter 100 to overcome the pre-curve. The guide catheter 100 can include a flexible elongate shaft 102, a joint 104, and a tip 106. The flexible elongate shaft 102 can include a generally proximal portion 108 to which the joint 104 is attached and a generally distal portion 110 that terminates at the tip 106. FIGS. 1A and 1B are discussed simultaneously unless otherwise specified.

[0053] Referring to FIG. 1A , the guide catheter 100 can be straightened along a central longitudinal axis CL to view various lengths (e.g., rigid portions) of the flexible elongate shaft 102. The flexible elongate shaft 102 can include an internal lumen (e.g., lumen 156 in FIG. 3 ) extending along the central longitudinal axis CL from a proximal end at the joint 104 to a distal end at the tip 106. The length L0 of the flexible elongate shaft 102 can be divided into multiple rigid portions between the joint 104 and the tip 106. The first rigid portion 112 can extend distally from the joint 104 to a second rigid portion 114. The second rigid portion 114 can extend distally from the first rigid portion 112 to a third rigid portion. The third rigid portion 116 can extend distally from the second rigid portion 114 to a fourth rigid portion. The fourth rigid portion 118 can extend distally from the third rigid portion 116 to the tip 106. The tip 106 can be positioned at the distal end of the fourth rigid portion 118 and can include a fifth rigid portion.

[0054] The rigid portions 112-118 and tip 106 can be configured to have different stiffness or hardness characteristics to facilitate the insertion process, cooperation with another instrument inserted therein, such as an insertion instrument for a flow modification device, and the withdrawal process. In examples, the portions 112-118 can be progressively less rigid or more flexible from the proximal portion 108 to the distal portion 110.

[0055] In an example, the length L0 of the flexible elongate shaft 102 can be approximately 610 millimeters + / - 10 millimeters. The first rigid portion 112 can have a length L1. In an example, the length L1 can be approximately 485 millimeters. The second rigid portion 114 can have a length L2. In an example, the length L2 can be approximately 50 millimeters. The third rigid portion 116 can have a length L3. In an example, the length L3 can be approximately 35 millimeters. The fourth rigid portion 118 can have a length L4. In an example, the length L4 can be approximately 38 millimeters. The tip 106 can have a length L5. In an example, the length L5 can be approximately 2 millimeters + / - 0.5 millimeters.

[0056] In examples, diameter D1 can be about 0.122 inches, or in a range of about 0.118 millimeters to about 0.123 inches. In additional examples, diameter D1 can be about 8 French, 9 French, or 10 French, and sizes therebetween.

[0057] In examples, the internal lumen within the flexible elongate shaft 102, i.e., lumen 156 in FIG. 3, can have a diameter of about 0.102 millimeters, or in the range of about 0.099 millimeters to about 0.103 millimeters.

[0058] In an example, the first rigid portion 112 can be made of a flexible material that is sufficiently rigid to facilitate insertion through a long length of biological structure and can resist bending from an insertion instrument inserted therein. In an example, the first rigid portion 112 can be stiffer than the rigid portions 114-118 and the tip 106. In an example, the first rigid portion 112 can have a hardness of 72 on the Shore D scale. In an example, the first rigid portion 112 can have a hardness ranging from about 67 Shore D to about 77 Shore D. In an example, the first rigid portion 112 can be made from a polymer such as polyether block amide (PEBA). In an example, the first rigid portion 112 can be made from a Pebax® material such as Pebax 7233D, commercially available from Arkema.

[0059] In an example, the second rigid portion 114 can be made of a material that is less rigid than the material of the rigid portion 112. In an example, the second rigid portion 114 can have a hardness of 63 on the Shore D scale. In an example, the second rigid portion 114 can have a hardness in the range of about 58 Shore D to about 68 Shore D. In an example, the second rigid portion 114 can be made from a polymer such as polyether block amide (PEBA). In an example, the second rigid portion 114 can be made from a Pebax® material such as Pebax 6333, commercially available from Arkema.

[0060] In an example, the third rigid portion 116 can be made of a material that is less rigid than the material of the rigid portion 114. In an example, the third rigid portion 116 can have a hardness of 55 on the Shore D scale. In an example, the third rigid portion 116 can have a hardness in the range of about 50 Shore D to about 65 Shore D. In an example, the third rigid portion 116 can be made from a polymer such as polyether block amide (PEBA). In an example, the third rigid portion 116 can be made from a Pebax® material such as Pebax 5533, commercially available from Arkema.

[0061] In an example, the fourth rigid portion 118 can be made of a material that is less rigid than the material of the rigid portion 116. In an example, the fourth rigid portion 118 can have a hardness of 35 on the Shore D scale. In an example, the fourth rigid portion 118 can have a hardness in the range of about 30 Shore D to about 40 Shore D. In an example, the fourth rigid portion 118 can be made from a polymer such as polyether block amide (PEBA). In an example, the fourth rigid portion 118 can be made from a Pebax® material such as Pebax 4033, commercially available from Arkema.

[0062] In an example, the tip 106, which may comprise the fifth rigid portion, may be made of a material that is less rigid than the material of the rigid portion 118. In an example, the tip 106 may have a hardness of 25 on the Shore D scale. In an example, the tip 106 may have a hardness ranging from about 20 Shore D to about 40 Shore D. In an example, the tip 106 may be made from a polymer such as polyether block amide (PEBA). In an example, the tip 106 may be made from a Pebax® material such as Pebax 2533, commercially available from Arkema.

[0063] The stiffness or hardness characteristics of the rigid segments 112-118 can additionally be identified on the guide catheter 100. In an example, text or numerical indicia can be printed on the rigid segments 112-118 to provide the stiffness of each segment. In an example, the rigid segments 112-118 can be color-coded, for example, by having segment 112 be the darkest colored segment and segments 114-118 that are gradually lighter in color. In examples, the first rigid portion 112 can have a 20% BaSO4 color additive to produce a Pantone 3265C color, the second rigid portion 114 can have a 20% BaSO4 color additive to produce a Pantone 3258C color, the third rigid portion 116 can have a 20% BaSO4 color additive to produce a Pantone 571C color, the fourth rigid portion 118 can have a 20% BaSO4 color additive to produce a Pantone 573C color, and the tip 106 can have a 20% BaSO4 color additive to produce a Pantone 573C color.

[0064] Additionally, the materials of the rigid sections 112-118 and the tip 106 can include additives such as barium sulfate, bismuth, or tungsten to promote radiopacity. In particular, the tip 106 can have radiopaque properties to facilitate insertion or use of the guide catheter 100.

[0065] The different stiffness of the stiff sections 112-118 and the tip 106 can facilitate insertion and use of the guide catheter 100. For example, increased stiffness toward the proximal section 108 can facilitate advancement through the anatomy during insertion, e.g., by pushing. Additionally, increased stiffness toward the proximal section 108 can inhibit deflection of the guide catheter 100 during insertion of other instruments through the guide catheter 100. Meanwhile, increased flexibility toward the distal section 110 can facilitate bending of the guide catheter 100, allowing for precise placement and preventing damage to tissue.

[0066] 1B, the distal portion 110 can be pre-curved such that the flexible elongate shaft 102 is curved back toward the joint 104 and the tip 106 points radially outward with a slight proximal orientation. The flexible elongate shaft 102 can have a proximal straight zone 120, a proximal curved zone 121, a distal straight zone 124, and a distal curved zone 126.

[0067] In an example, guide catheter 100 can have at least two curved zones and one straight zone. In an example, guide catheter 100 can have two curved zones separated by a straight zone. In an example, each of the curved zones can have portions with different radii of curvature.

[0068] As discussed with reference to FIG. 2, zones 120-126 can facilitate the conformance of guide catheter 100 to particular anatomical features, which can facilitate the insertion of guide catheter 100 and the insertion of other instruments through guide catheter 100.

[0069] 2 is an enlarged side view of the distal portion 110 of the guide catheter 100 of FIG. 1B showing multiple curved zones with pre-curves. The proximal straight zone 120 and the distal straight zone 124 can have zero curvature. The proximal curved zone 121 can have a first segment 122 and a second segment 123. The distal curved zone 126 can have a first segment 128, a second segment 130, a third segment 132, a fourth segment 134, and a fifth segment 136.

[0070] Zones 120-126 can be interrelated with rigid portions 112-118 and tip 106. Proximal straight zone 120 and proximal curved zone 121 can comprise first rigid portion 112. Distal straight zone 124 and first segment 128 can comprise second rigid portion 114. Second segment 130 and third segment 132 can comprise third rigid portion 116. Fourth segment 134 and fifth segment 136 can comprise fourth rigid portion 118.

[0071] The proximal straight zone 120 can extend from the joint 104 to the proximal curved zone 121. The proximal curved zone 121 can extend from the proximal straight zone 120 to the distal straight zone 124. The first segment 122 can extend from the proximal straight zone 120 to the second segment 123. The second segment 123 can extend from the first segment 122 to the distal straight zone 124. The distal straight zone 124 can extend from the proximal curved zone 121 to the first segment 128. The first segment 128 can extend from the distal straight zone 124 to the second segment 130. The second segment 130 can extend from the first segment 128 to the third segment 132. The third segment 132 can extend from the second segment 130 to the fourth segment 134. The fourth segment 134 can extend from the third segment 132 to the fifth segment 136. The fifth segment 136 can extend from the fourth segment 134 to the tip 106.

[0072] The proximal linear zone 120 can have a length that is less than the length L1, which is the length of the first rigid portion 112 (FIG. 1A). In an example, the proximal linear zone 120 can have a linear length of about 412 millimeters + / - 10 millimeters.

[0073] The first segment 122 of the proximal curved zone 121 can have a radius of curvature R1. In an example, the radius of curvature R1 can be approximately 794.37 millimeters. In an example, the radius of curvature R1 can be in a range from approximately 784 millimeters to approximately 804 millimeters. In an example, the first segment 122 can have an arc length of approximately 45 millimeters + / - 5 millimeters.

[0074] The second segment 123 of the proximal curved zone 121 can have a radius of curvature R2. In an example, the radius of curvature R2 can be approximately 219.15 millimeters. In an example, the radius of curvature R2 can be in a range from approximately 209 millimeters to approximately 229 millimeters. In an example, the second segment 123 can have an arc length of approximately 28 millimeters + / - 5 millimeters.

[0075] The distal linear zone 124 can have a length L7. In an example, the distal linear zone 124 can have a linear length of about 32.5 millimeters + / - 5 millimeters.

[0076] The first segment 128 of the distal curved zone 126 can have a radius of curvature R3. In an example, the radius of curvature R3 can be approximately 71.7 millimeters. In an example, the radius of curvature R3 can be in a range from approximately 61 millimeters to approximately 81 millimeters. In an example, the first segment 128 can have an arc length of approximately 17.5 millimeters + / - 5 millimeters.

[0077] The second segment 130 of the distal curved zone 126 can have a radius of curvature R4. In an example, the radius of curvature R4 can be approximately 26.18 millimeters. In an example, the radius of curvature R4 can be in a range from approximately 21 millimeters to approximately 31 millimeters. In an example, the second segment 130 can have an arc length of approximately 14 millimeters + / - 5 millimeters.

[0078] The third segment 132 of the distal curved zone 126 can have a radius of curvature R5. In an example, the radius of curvature R5 can be approximately 35.63 millimeters. In an example, the radius of curvature R5 can be in a range from approximately 30 millimeters to approximately 40 millimeters. In an example, the third segment 132 can have an arc length of approximately 21 millimeters + / - 5 millimeters.

[0079] The fourth segment 134 of the distal curved zone 126 can have a radius of curvature R6. In an example, the radius of curvature R6 can be approximately 68.19 millimeters. In an example, the radius of curvature R6 can be in a range from approximately 63 millimeters to approximately 73 millimeters. In an example, the fourth segment 134 can have an arc length of approximately 16 millimeters + / - 5 millimeters.

[0080] The fifth segment 136 of the distal curved zone 126 can have a radius of curvature R7. In an example, the radius of curvature R7 can be approximately 125.75 millimeters. In an example, the radius of curvature R7 can be in a range from approximately 115 millimeters to approximately 135 millimeters. In an example, the fifth segment 136 can have an arc length of approximately 22 millimeters + / - 5 millimeters.

[0081] As stated, the tip 106 can have a linear length of about 2.0 millimeters + / - 0.5 millimeters.

[0082] The radii of curvature R1 and R2 of the proximal curved zone 121 may result in the distal end of the first rigid portion 112 being disposed at an angle A1 relative to the proximal straight zone 120. In an example, the angle A1 may be approximately 10.5 degrees. In an example, the angle A1 may range from approximately 8.5 degrees to approximately 12.5 degrees.

[0083] The radius of curvature R3 of the first segment 128 may result in the distal end of the second rigid portion 114 being disposed at an angle A2 relative to the proximal straight zone 120. In an example, the angle A2 may be approximately 28.2 degrees. In an example, the angle A2 may range from approximately 23 degrees to approximately 33 degrees.

[0084] The radius of curvature R4 of the second segment 130 and the radius of curvature R5 of the third segment 132 may result in the distal end of the third rigid portion 116 being disposed at an angle A3 relative to the proximal linear zone 120. In an example, the angle A3 may be approximately 86.5 degrees. In an example, the angle A3 may range from approximately 76 degrees to approximately 96 degrees.

[0085] The radius of curvature R6 of the fourth segment 134 and the radius of curvature R7 of the fifth segment 136 may result in the distal end of the fourth rigid portion 118 being disposed at an angle A4 relative to the proximal straight zone 120. In an example, the angle A4 may be approximately 62.0 degrees. In an example, the angle A4 may range from approximately 52 degrees to approximately 72 degrees.

[0086] 4A and 4B, zones 120-126 can be configured to extend along natural anatomical pathways. In the disclosed example, zones 120-126 mimic the pathways created by the superior vena cava, right atrium, and coronary sinus. In other examples, guide catheter 100 can be shaped to fit other anatomical pathways, such as other vascular pathways.

[0087] 1A and 1B illustrating the various layers forming the flexible elongate shaft 102. The flexible elongate shaft 102 can comprise an inner layer 150, a reinforcing layer 152, and an outer layer 154. A lumen 156 can extend through the flexible elongate shaft 102. In certain examples, the inner layer 150, the reinforcing layer 152, and the outer layer 154 can comprise a single, integrated unit, where the outer layer 154, the reinforcing layer 152, and the inner layer 150 are pre-assembled into a unit defining the lumen 156 extending along a centerline CL. In examples, the inner layer 150 and the outer layer 154 can be formed around, e.g., melted to, the reinforcing layer 152.

[0088] The outer layer 154 can provide a protective covering for the other components of the guide catheter 100. The outer layer 154 can comprise a waterproof, biocompatible material that defines a lumen for the location of other components, such as the reinforcing layer 152 and the inner layer 150. The material used to form the outer layer 154 can vary depending on the stiffness desired for the guide catheter 100. In examples, the outer layer 154 can be fabricated from nylon and polyamides such as DURETHAN®, polyetheretherketone (PEEK), polyimide (PI), and polyetherimide (PEI), commercially available from Bayer. As discussed, the outer layer 154 can be fabricated from polyether block amide (PEBA). In examples, the outer layer 154 can be fabricated from polyamides such as CRISTAMID®, commercially available from Arkema, which provides a hardness durometer slightly below that of rigid polyamides and slightly above that of flexible PEBA materials. In an example, the material of the outer layer 154 can have a crystal growth rate that supports a crystalline morphology. Additionally, these materials can have a crystal growth rate that allows their crystalline microstructure to be modified during the nucleation process, thereby facilitating curve preshaping. In an additional example, the outer layer 154 can be fabricated from a material with a fast crystal growth rate that does not provide a crystalline morphology suitable for curve preshaping. In such an example, a nucleating agent can be added to the material to promote the formation of the crystalline structure.

[0089] The reinforcement layer 152 can comprise a tubular body formed from individual strands or bundles of strands woven, knitted, or braided together to form the tubular body. In an example, the reinforcement layer 152 can comprise wire mesh tubing fabricated from stranded metal wire, such as stainless steel. In an example, the reinforcement layer 152 can comprise braided reinforcement made from 0.002-inch (0.0508 mm) wire of 304 stainless steel with 16 carrier constructions in a herringbone pattern wound at 90 picks per inch (PPI). The reinforcement layer 152 provides reinforcement to the outer layer 154 and can therefore be used to provide additional stiffening properties or prevent radial expansion. In another example, the reinforcement layer 152 can comprise spiral band tubing formed from one or more strands of material wound in a helical spiral. The reinforcement layer 152 can extend along the entire flexible elongate shaft 102 or only a portion of the flexible elongate shaft 102. In examples, the reinforcing layer 152 can extend from the joint 104 to a location before the tip 106 at the distal end of the fourth rigid portion 118 or to a location short of the distal end of the fourth rigid portion 118 .

[0090] The inner layer 150 can define a lumen 156, which provides a passageway for another instrument or device through the guide catheter 100. The lumen 156 of the inner layer 150 can be lined with a coating or material to reduce friction therein and facilitate sliding of the instrument therethrough. In an example, the lumen 156 can be lined with polytetrafluoroethylene (PTFE). In an example, the inner layer 150 can be made from the same materials listed above with respect to the outer layer 154. In an example, the inner layer 150 and the outer layer 154 can be made from the same material. In other examples, the inner layer 150 and the outer layer 154 can be made from different materials.

[0091] To introduce a pre-curve into guide catheter 100, the material of flexible elongate shaft 102 can be positioned around a forming mandrel that can be shaped into the desired curvature, and then heated, allowing the material to take the shape of the mandrel by allowing the polymer crystals to form at a slow growth rate and retain the curvature of the mandrel. For example, guide catheter 100 can be heated to about 280° F. (about 138° C.). In examples, the manufacture of guide catheter 100 and the pre-curve imparted therein can be performed using conventional manufacturing techniques known in the art.

[0092] 4A is a schematic diagram showing guide catheter 100 deployed within a human heart 170. Heart 170 comprises superior vena cava 172S, right atrium 173, tricuspid valve 174, and right ventricle 175. Right atrium 173 may be connected to coronary sinus 176 via coronary sinus ostium 177. During normal operation of heart 170, deoxygenated blood is pumped into right atrium 173 through superior vena cava 172S and inferior vena cava 172I. Major veins supplying blood to superior vena cava 172S include right and left axillary veins 178R and 178L, which drain into right and left subosseous veins 179R and 179L. The right and left external necks 171RE and 171LE, along with the right and left internal necks 171RI and 171LI, join the right and left twisted subosseous veins 179R and 179L to form the right and left brachiocephalic veins, which combine and drain into the superior vena cava 172S.

[0093] In an example, catheter 100 can be introduced into coronary sinus 176 via jugular access. In a specific example, catheter 100 can be introduced through the right external jugular vein 171RE. In the illustrated example, guide catheter 100 can be inserted into jugular vein 171LI, superior vena cava 172S, right atrium 173, sinus ostium 177, and coronary sinus 176. Thus, tip 106 (FIG. 1A) is positioned within coronary sinus 176 and can deliver, for example, a flow modification device 202 (FIG. 4A). In other examples of the invention, catheter 100 can enter the vasculature through left axillary vein 178L, right external jugular vein 171RE, left internal jugular vein 171LI, or left brachiocephalic vein.

[0094] In examples, the coronary sinus 176 can be reached using the guide catheter 100 via a twisted subosseous route or via a transfemoral route.

[0095] 4B is a schematic illustration of a guide catheter 100 of the present disclosure being inserted into a heart 170. The heart 170 can include a superior vena cava 172S, a right atrium 173, a coronary sinus ostium 177, and a coronary sinus 176.

[0096] Guide catheter 100 can be pre-shaped to match the anatomy of a desired insertion path. In an example, guide catheter 100 can be pre-shaped to match the shape of superior vena cava 172S, coronary sinus ostium 177, and coronary sinus 176. In particular, proximal straight zone 120 can be shaped to extend along superior vena cava 172S, proximal curved zone 121 and distal straight zone 124 can be shaped to extend through right atrium 173, and distal curved zone 126 can be shaped to extend through coronary sinus 176. Distal straight zone 124 can be positioned by proximal curved zone 121 to extend across all or a portion of right atrium 173. The straightness of distal straight zone 124 can resist bending of guide catheter 100 away from coronary sinus ostium 177 as instrumentation is deployed through guide catheter 100. The distal curved zone 126 can extend through the coronary sinus ostium 177 and into the coronary sinus 176. The curvature of the distal curved zone 126 facilitates entry into and extension along the coronary sinus ostium 177, thereby reducing stress on the coronary sinus ostium 177 and the coronary sinus 176 and reducing tissue pushing against the guide catheter 100.

[0097] As shown in FIG. 4B, guide catheter 100 can be inserted into heart 170 and tip 106 can be positioned within coronary sinus 176. An insertion device or another instrument, such as a catheter, can then be inserted into guide catheter 100 to deliver an implant or prosthetic device to coronary sinus 176. In the illustrated example, the insertion device can include a balloon catheter 200 used to position flow modification device 202. Flow modification device 202 is shown in FIG. 4B in an undeployed state, collapsed to a small diameter suitable for passage through lumen 156 (FIG. 3) of guide catheter 100.

[0098] 5A is a schematic diagram showing a guide catheter 100 having a balloon catheter 200 inserted therein to expand a flow modification device 202. The flow modification device 202 can include an inflow portion 204, an outflow portion 206, and a restriction portion 208. The balloon catheter 200 can be used to insert a balloon 210 into the flow modification device 202 and inflate the balloon 210, expanding the flow modification device 202 to the deployed configuration shown. Prior to deployment, the flow modification device 202 can be collapsed to approximately the diameter of the shaft 212 of the balloon catheter 200. The balloon catheter 200 can be configured to deploy the inflow portion 204 distal to the outflow portion 206. In other configurations, the balloon catheter 200 can be configured to insert the flow modification device 202 in the opposite orientation, whereby the inflow portion 204 faces toward the balloon catheter 200. The guidewire 213 can be used to position the shaft 212 of the balloon catheter 200 within the anatomy.

[0099] Flow modification device 202 can be configured to reduce blood flow through flow modification device 202 in one direction. In an example, inflow portion 204 can be smaller than outflow portion 206. In an example, one of inflow portion 204 and outflow portion 206 can be omitted. Inflow portion 204 and outflow portion 206 can include flared portions, which are reduced in diameter leading into restriction portion 208. Thus, the walls of inflow portion 204 and outflow portion 206 can be angled relative to the walls of coronary sinus 176 ( FIG. 4A ), and the walls of restriction portion 208 can be parallel or nearly parallel to the walls of coronary sinus 176.

[0100] The flow modification device 202 can be radially expandable, which can cause a corresponding reduction in the length of the flow modification device 202. In an example, the flow modification device 202 can have a length of approximately 20 mm before expansion to approximately 18.8 mm after expansion. An exemplary thickness of the material of the flow modification device 202 can be approximately 0.15 mm; however, thinner or thicker materials can also be used. Other exemplary lengths of the flow modification device 202 are 5 mm, 12 mm, 24 mm, 35 mm, 45 mm, and any smaller, intermediate, or larger sizes. The length is optionally selected to match the physiological size (e.g., length and curvature) of the target vein and / or to ensure good contact with the venous wall. The length of the restriction portion 208 can be, for example, 0.5 mm, 1 mm, 2 mm, 3 mm, 5 mm, or any smaller, intermediate, or larger length and can be selected, for example, to achieve desired flow dynamics. Exemplary inner diameters of inflow portion 204 and outflow portion 206 can be 2 mm to 30 mm, e.g., 5 mm, 10 mm, 15 mm, 20 mm, or any larger, smaller, or intermediate diameter, and can be selected, e.g., to match the vein diameter. The inner diameter of restriction portion 208 can be, e.g., 1 mm, 2 mm, 3 mm, 5 mm, 10 mm, or any smaller, larger, or intermediate diameter, and can be selected, e.g., to achieve desired flow dynamics and / or pressure differential across the flow modifying device.

[0101] In exemplary embodiments of the invention, the ratio between the cross sections of restriction portion 208 and inlet portion 204 and outlet portion 206 can be 0.9, 0.8, 0.6, 0.4, 0.2, or any larger, smaller, or intermediate ratio, and can be selected to achieve desired flow dynamics and / or pressure differential across flow modification device 202, for example.

[0102] Although a circular cross-section is shown, other cross-sections, such as polygonal and elliptical, can be used. A potential advantage of a non-circular cross-section is that the implant is less likely to move axially and / or rotate. Alternatively, or in addition, the exterior of the flow modification device 202 can be roughened and / or otherwise adapted to adhere to the vein wall. The cross-sectional shape and / or orientation can optionally vary along the length of the flow modification device 202.

[0103] In examples, flow modification device 202 can be fabricated from a mesh-type material, such as a woven open material of metal and / or plastic fibers, using methods known in the art. In examples, flow modification device 202 can be formed by cutting a sheet or tube of metal, for example, using a laser, water cutting, chemical etching, or metal stamping (e.g., the result is welded to form a tube). In examples, all or a portion of flow modification device 202 can be covered by a covering of fabric, plastic, tissue, etc.

[0104] In an example, the flow modification device 202 can be constructed similarly to the device described in US 2020 / 0178978 A1, entitled "Methods for treating abnormal growth in the body using a flow reducing implant" by Shmuel et al., the contents of which are hereby incorporated by reference herein.

[0105] In the deployed state, the flow modification device 202 can have a diameter D2 at the restriction portion 208 and a diameter D3 at the outflow portion 206. In an example, the inflow portion 204 and the outflow portion 206 can have the same diameter. In an example, the inflow portion 204 can be larger than the outflow portion 206.

[0106] A fluid, such as an 80 / 20 blend of saline and contrast agent, can be introduced into balloon 210 via shaft 212 to expand flow modification device 202. Either before, during, or after expansion, the surgeon can position flow modification device 202 at the desired location. Once properly positioned and expanded to the desired diameter, balloon catheter 200 can be detached from flow modification device 202, leaving flow modification device 202 deployed and implanted within the anatomy. To retract balloon catheter 200 back into guide catheter 100, balloon catheter 200 can be retracted proximally into guide catheter 100, bringing balloon 210 inside guide catheter 100. However, balloon 210 does not always fully deflate when the application of compressed air is stopped, for example, due to stretching of the balloon 210 material. Thus, when balloon catheter 200 is pulled proximally, the material of balloon 210 may engage tip 106 and the outer surface of guide catheter 100. In some cases, engagement of the material of balloon 210 with guide catheter 100 may cause tip 106 of guide catheter 100 to invaginate or close upon itself, thereby making advancement of balloon 210 into guide catheter 100 difficult or impossible. Thus, guide catheter 100 may include enlarged tip 214, as shown in FIG. 5B , to facilitate insertion of balloon 210 into guide catheter 100. In an example, enlarged tip 214 may be shaped to gently engage balloon 210 and urge balloon 210 back into guide catheter 100 in its deflated state.

[0107] FIG. 5B is a schematic diagram showing the guide catheter 100 of FIG. 5A extended into a flow modification device 202. In the example of FIG. 5B, the guide catheter 100 includes an enlarged tip 214. When the balloon 210 is advanced into the guide catheter 100, the guide catheter 100 may advance forward or distally, allowing it to engage the flow modification device 202. In some cases, the distal tip of the guide catheter 100 may become embedded inside the restriction 208. For example, the diameter D3 of the deployed flow modification device 202 and the outer diameter D1 of the guide catheter 100 may both be 9 French, thereby allowing the tip 106 (FIG. 1A) of the guide catheter 100 to become wedged into the restriction 208. Thus, the guide catheter 100 includes an enlarged tip 214, which can prevent engagement of the guide catheter 100 with the restriction 208. Various configurations of enlarged tips suitable for use as the enlarged tip 214 are described with reference to FIGS. 7A-10.

[0108] Figure 6A is a perspective view of a proximal portion 108 of a guide catheter 100 of the present disclosure including a fitting 104. Figure 6B is a side view of the fitting 104 of Figure 6A including an annular body 180 and a coupler 182. Figure 6C is an end view of the fitting 104 of Figure 5A showing wings 184A and 184B extending from the coupler 182. Wing 184A may include indicia 186. Figures 6A-6C will be discussed simultaneously.

[0109] The fitting 104 can include a device that facilitates coupling of the flexible elongate shaft 102 to another device (such as an insertion tool for an implantable medical device). The fitting 104 can include an annular body 180 that includes a coupler 182, which can be located at a proximal end of the annular body 180 and allow another device to be attached to the fitting 104. The coupler 182 can include a flange. In an example, the flange of the coupler 182 can include an element (one or more threads, notches, grooves, etc.) to allow the other device to engage with the coupler 182. In the illustrated example, the coupler 182 can include a helical slot for a twist-lock mechanism. In an example, the fitting 104 can include a female luer adapter.

[0110] In an example, a guide catheter can be used to guide a deployable prosthetic device through the guide catheter 100. The annular body 180 can include a passageway 188, which can connect to a lumen 156 (FIG. 3) in the flexible elongate shaft 102. Thus, the passageway 188 can extend continuously from the proximal end of the annular body 180 to the tip 106 (FIG. 1A). The passageway 188 can be flared, such that the proximal end is larger than the distal end to facilitate insertion into the fitting 104 of another device and subsequently into the lumen 156.

[0111] Indicia 186 can be located on wing 184A. Indicia 186 can provide visual or tactile feedback to a user regarding the orientation of tip 106 relative to joint 104. In particular, indicia 186 can indicate the direction toward which tip 106 is prone to curve. In the illustrated example, indicia 186 comprises an elongate body 190 having a proximal end 192A, a distal end 192B, and a curved portion 194. In the example, indicia 186 can be located on both sides of wing 184A. Thus, elongate body 190 can extend from one side of wing 184A through to the opposite side of wing 184A such that elongate body 190 has the same shape throughout.

[0112] The elongate body 190 can extend parallel to the proximal portion of the flexible elongate shaft 102 from the proximal end 192A to the curved portion 194, which can extend radially away from the proximal portion of the flexible elongate shaft 102 such that the distal end 192B is positioned radially outward of the proximal end 192A relative to the axis of the flexible elongate shaft 102. The distal end 192B can therefore protrude in the same direction that the guide catheter tip 106 protrudes. In other words, the plane in which the proximal and distal ends 192A and 192B curve can be the same plane in which the flexible elongate shaft 102 is pre-curved; for example, the tip 106 curves away from the proximal portion of the flexible elongate shaft 102 in the same plane direction in which the distal end 192B curves away from the proximal end 192A.

[0113] Elongate body 190 can include raised protrusions that project outward from wings 184A. Thus, elongate body 190 can provide tactile feedback to the user. For example, a user can slide their fingertip or thumb over indicia 186 while looking elsewhere to get an understanding of the direction of pre-curve of guide catheter 100. In other examples, indicia 186 can include other shapes or geometries. For example, elongate body 190 can be recessed or engraved into wings 184A. In an example, indicia 186 can include an arrow pointing in the direction of pre-curve. In an example, a text indicia such as a statement including "pre-curved in this direction" or similar language can also be used.

[0114] Figure 7A is a perspective view of the distal portion 110 of the presently disclosed guide catheter 100, which includes a flared tip 250. Figure 7B is a side view of the distal portion 110 of Figure 7A, showing the flared tip 250. Figures 7A and 7B will be discussed simultaneously.

[0115] 1A-2. The flared tip 250 can include an annular edge 252 and a conical edge 254. The flared tip 250 can extend from the flexible elongate shaft 102 at an angle A5 relative to the central longitudinal axis CL.

[0116] The flared tip 250 can comprise an extension of the material of the flexible elongate shaft 102. In particular, the conical edge 254 can comprise the tip 106 (FIG. 1A), and the conical edge 254 can comprise an extension of the tip 106. In other examples, the flared tip 250 can comprise an attachment to the flexible elongate shaft 102.

[0117] The diameter D1 of the flexible elongate shaft 102 can be selected to fit within a desired anatomy, such as the coronary sinus. In examples, the diameter D1 can range from about 8 French (2.667 mm) to about 10 French (3.33 mm). In a specific example, the diameter D1 can be about 9 French (3 mm).

[0118] Angle A5 can be selected to provide a wider end for the flexible elongate shaft 102, allowing other components to be more easily pulled proximally into the flexible elongate shaft 102. Thus, the conical edge 254 can have the same or approximately the same thickness as the rest of the flexible elongate shaft 102. However, the opening in the conical edge 254 can be wider than the lumen 156 (FIG. 3) in the flexible elongate shaft 102. Angle A5 can be selected so that diameter D4 is larger than diameter D1. In an example, angle A5 can range from about 15 degrees to about 45 degrees. In a specific example, angle A5 can be about 30 degrees. In an example, the axial length L6 of the conical edge 254, e.g., the distance covered with respect to the central longitudinal axis CL, can be about 0.5 mm to about 2.5 mm. Angle A5 and length L6 can be varied to achieve a desired value for diameter D4. Diameter D4 can be about 0.25 mm to 0.5 mm larger than diameter D2 of restrictive portion 208 of flow modification device 202, which can allow guide catheter 100 to be used to hold restrictive portion 208 of flow modification device 202 in place while withdrawing balloon 210, as shown in FIG. 7D. Diameter D4 can be selected to be about 0.25 mm to about 0.5 mm larger than diameter D1. In a particular example, D2 can be about 10 French.

[0119] 5B, the conical edge 254 can be sized and shaped to provide at least two functions. First, the conical edge 254 can allow the balloon 210 (FIG. 5A) to be guided back into the flexible elongate shaft 102. The angle A5 can be selected to generally match the shape of the balloon 210. For example, the angle A5 can be selected to tangent to the curved surface of the balloon 210 facing toward the flared tip 250, thereby facilitating the funnel-shaped material of the balloon 210 to return into the guide catheter 100. The flared tip 250 can thereby engage the balloon 210 in a non-axial manner, e.g., the force of the flared tip 250 generated against the balloon 210 can be directed radially inward. In an example, the conical edge 254 can have a shape or curvature to more closely match the shape of the balloon 210. In an example, the conical edge 254 can have a parabolic or elliptical curvature. Thus, the conical edge 254 can prevent invagination of the tip 106 of the flexible elongate shaft 102 during retrieval of the balloon 210. Second, the conical edge 254 can prevent the guide catheter 100 from being inserted into the flow modification device 202, particularly the restrictive portion 208, as can be seen in FIG. 7D . In an example, the flared tip 250 can stop the guide catheter 100 at a length La that can be approximately 1.5 to 2.5 millimeters from the center of the restrictive portion 208. The shape and position of the flared tip 250 can be selected to match the curvature and shape of the restrictive portion 208 so that the outer surface of the flared tip 250 can mate against the surface of the restrictive portion 208, thereby providing frictional engagement and distributing forces.

[0120] 7C is a perspective view of the distal portion 110 of the guide catheter 100 of FIG. 7A protruding from a retracting sheath 258. The retracting sheath 258 can comprise a tubular body having an internal lumen 259 for receiving the flexible elongate shaft 102. The internal lumen 259 can have a diameter sized to receive the flexible elongate shaft 102. In an example, the internal lumen 259 can be sized to allow the flexible elongate shaft 102 to slide freely within the internal lumen 259. In an example, the internal lumen 259 can be lined with PTFE. The retracting sheath 258 can be used to prevent prolapse of the conical lip 254 and to bias the conical lip 254 to a reduced diameter state to facilitate passage through anatomy, such as by reducing the size of the conical lip 254. In an example, the outer diameter of the containment sheath 258 can be approximately 10 French for use with an embodiment of the guide catheter 100 having a diameter D1 of 9 French.

[0121] Figure 8A is a perspective view of the distal portion 110 of the presently disclosed guide catheter 100 including the prolapse tip 260. Figure 8B is a side view of the distal portion 110 of Figure 8A, showing the prolapse tip 260. Figures 8A and 8B will be discussed simultaneously.

[0122] 1A-2 。 In another example, the escape tip 260 can include an attachment to the guide catheter 100. The escape tip 260 can include an annular edge 262, a conical edge 264, and a curved portion 266. The conical edge 264 can be spaced from the annular edge 262 to form a space 268. The escape tip 260 can extend from the flexible elongate shaft 102 at an angle A6 relative to the central longitudinal axis CL. The escape tip 260 can have an axial length L7, which is the distance covered about the central longitudinal axis CL. The escape tip 260 can have an outer diameter D5.

[0123] The escape tip 260 can be pre-shaped into the shape shown in FIGS. 8A-8C or predisposed to the shape shown in FIGS. 8A-8C. The shape of the escape tip 260 can be configured to correspond to a corresponding shape on a medical device to be deployed with the guide catheter 100. In an example, the escape tip 260 can be shaped to match the shape of one or both of the outflow portion 206 and the inflow portion 204 of the flow modification device 202. The angle A6 can be selected to generally match the shape of the inflow portion 204 and the outflow portion 206. In an example, the conical edge 264 can have a shape or curvature to more closely match the shape of the inflow portion 204 and the outflow portion 206. In an example, the conical edge 264 can have a parabolic or elliptical curvature.

[0124] In an example, the outer diameter D5 of the prolapse tip 260 can be selected to be about 0.25 mm to about 5 mm larger than the diameter D1. In an example, the angle A6 can range from about 15 degrees to about 45 degrees. The diameter D5 can be about 0.25 mm to 0.5 mm larger than the diameter D2 of the restricting portion 208 of the flow modification device 202, which can allow the guide catheter 100 to be used to hold the restricting portion 208 of the flow modification device 202 in place while withdrawing the balloon 210, as shown in FIG. 8D. In an example, the length L7 can be about 0.5 mm to about 1.5 mm. The angle A6 and the length L7 can be varied to achieve a desired value for the diameter D5.

[0125] The shape of the escape tip 260 can be thermally solidified via activating the crystalline microstructure of the polymer material forming the escape tip 260. In an example, the escape tip 260 can be reinforced with another material to provide the escape shape, such as one or more strands or tubes of Nitinol (nickel titanium) braid.

[0126] 5B, the escape tip 260 can be sized and shaped to provide at least two functions. First, the escape tip 260 can allow the balloon 210 (FIG. 5A) to be guided back into the flexible elongate shaft 102. For example, the curved portion 266 can be shaped, e.g., curved or rounded, to engage the balloon 210 in a non-binding manner, e.g., by avoiding point contact and urging the balloon 210 back into the guide catheter 100. The escape tip 260 can thereby engage the balloon 210 in a non-axial manner, e.g., the force of the escape tip 260 generated against the balloon 210 can be directed radially inward. The presence of the conical edge 264 around the annular edge 262 can reinforce the flexible elongate shaft 102, thereby preventing invagination of the tip 106 of the flexible elongate shaft 102 during retrieval of the balloon 210. Second, the conical edge 264 can prevent the guide catheter 100 from being inserted into the flow modification device 202, particularly the restrictive portion 208, as shown in FIG. 8D. In an example, the escape tip 260 can stop the guide catheter 100 at a length Lb (which can be approximately 1.5 to 2.5 millimeters) from the center of the restrictive portion 208. The shape and position of the escape tip 260 can be selected to match the curvature and shape of the restrictive portion 208 so that the outer surface of the escape tip 260 can mate against the surface of the restrictive portion 208, thereby providing frictional engagement and distributing forces.

[0127] 7C 。 Containment sheath 258 can be used to prevent conical edge 264 from engaging tissue and to deflect conical edge 264 to an axially straightened position aligned with flexible elongate shaft 102, for example, by reducing the size of conical edge 264 to facilitate passage through the anatomy. In an example, the outer diameter of containment sheath 258 can be approximately 10 French for use with an embodiment of guide catheter 100 having a diameter D1 of 9 French.

[0128] In an example, the tip 106 can be configured to prolapse upon insertion into an annular body, such as an anatomical vessel, another catheter, an insertion device, or an implantable device. Accordingly, the curved portion 266 can be replaced by a bendable portion, which is pre-curved or prone to be pre-curved into an axial shape, with the conical edge 264 axially aligned with the flexible elongate shaft 102. Thus, when the flexible elongate shaft 102 is pushed forward, friction generated between the conical edge 264 and the surrounding annular tube can cause the conical edge 264 to tip over from axially aligned with the flexible elongate shaft 102 to the position shown. In such an example, a portion of the conical edge 264 can be narrowed, thinned, or made from a low durometer (e.g., flexible) material in which the curved portion 266 is located. If the escape tip 260 is configured to bend into the escaped shape upon insertion, the need for an insertion catheter such as the retraction sheath 258 of FIG. 7C can be eliminated.

[0129] Figure 9A is a perspective view of the distal portion 110 of a guide catheter 100 of the present disclosure, including a balloon tip 270. Figure 9B is a side view of the distal portion 110 of Figure 9A, showing the balloon tip 270. Figure 9C is a side cross-sectional view of the guide catheter 100 of Figure 9B, showing the interior chamber 276 of the balloon tip 270. Figures 9A-9C will be discussed simultaneously.

[0130] 1A-2 。 Balloon tip 270 can include an extension of tip 106 of FIG. 1A-2 . Balloon tip 270 can include an annular rim 272 and a bulbous body 274. Balloon tip 270 can include an interior chamber 276, which can be fluidly connected to a passageway 278 extending through flexible elongate shaft 102. Balloon tip 270 can have an axial length L8, which is the distance covered relative to central longitudinal axis CL. Balloon tip 270 can have an outer diameter D6.

[0131] The balloon tip 270 can be configured to allow easy passage through the anatomy in a first configuration, for example, by having a diameter no greater than diameter D1, and to prevent prolapse and impingement of the tip 106 in a second configuration, for example, by having a diameter greater than diameter D2 (FIG. 5B) to hold the flow modification device 202 in place while withdrawing the balloon 210, as shown in FIG. 9D. In an example, the balloon tip 270 in the first configuration can be folded and the internal chamber 276 can be contracted so that diameter D6 is equal to diameter D1 of the restriction portion 208 of the flow modification device 202, and the balloon tip 270 in the second configuration can be expanded and the internal chamber 276 can be inflated so that diameter D6 is greater than diameter D2, as shown in FIG. 9D. In an example, the balloon tip 270 can stop the guide catheter 100 at a length Lc (which can be approximately 1.5 to 2.5 millimeters) from the center of the restriction portion 208. The curvature of balloon tip 270 can be selected to match the curvature and shape of restrictive portion 208 so that the outer surface of balloon tip 270 can mate against the surface of restrictive portion 208, thereby providing frictional engagement and distributing force. A passageway 278 can extend proximally from chamber 276 and can be configured to connect to a source of pressurized gas or air. In an example, passageway 278 can extend through flexible elongate shaft 102 and connect to a port on fitting 104, which can connect to a source of pressurized gas or air.

[0132] FIG. 10 is a side view of the distal portion 110 of the presently disclosed guide catheter 100 including a funnel-shaped tip 290. The funnel-shaped tip 290 can include a conical body 292 having a length L9 and a larger diameter D7. The diameter D7 can be selected to exceed the restricted portion 208 of the flow modification device 202 by approximately 0.25 mm to 0.5 mm and to hold the flow modification device 202 in place while the balloon 210 is being withdrawn. The funnel-shaped tip 290 can be similar to the flared tip 250 of FIGS. 7A and 7B , except that the funnel-shaped tip 290 can extend over a longer axial length. The length L6 of the flared tip 250 is generally 5 mm or less, while the length L9 can range from about 10 mm to about 20 mm. The conical body 292 can additionally include a curvature to conform to the shape of the flow modification device 202. The conical body 292 can be made from a flexible material to facilitate navigation, or can be stiffened to prevent invagination.

[0133] 11 is a diagram illustrating operations of a method 400 of implanting a flow modification device 202 according to the present disclosure. Method 400 illustrates a particular sequence of operations. However, not all operations need to be performed in all methods of the present disclosure. In addition, some operations can be performed in a different sequence. Method 400 is described with reference to implanting a flow modification device in the coronary sinus of the heart via jugular access. However, other procedures can also be performed using the devices and methods described herein.

[0134] In operation 402, access to the heart may be opened in the patient. In an example, access to the heart may be obtained via the carotid artery. In an additional example, access to the heart may be obtained via the femoral artery.

[0135] In operation 404, a guidewire, such as guidewire 213, may be navigated through the anatomy to reach a target area within the heart. In an example, the guidewire may be inserted using a multi-purpose catheter that may be steered and / or navigated. In an example, the target area may be the coronary sinus. The guidewire may be navigated through a jugular vein, such as the left external jugular vein 171LE (FIG. 4A), through the superior vena cava 172S (FIG. 4B), through the coronary sinus ostium 177, and into the coronary sinus 176.

[0136] In operation 406, a guide catheter, such as guide catheter 100, may be navigated through the anatomy to reach the target area. The guide catheter may be slid over the guidewire used in operation 404. In other examples, the use of a guidewire may be omitted. Guide catheter 100 may be inserted such that tip 106 is positioned within coronary sinus 176.

[0137] In operation 408, the guide catheter may be directed along the anatomical path to the target area. Specifically, the guide catheter 100 may be directed such that the pre-curve of the distal portion 110 follows the shape of the anatomical path of the access route. For example, the pre-curve may be oriented to extend along the superior vena cava and coronary sinus, conforming to the shape of the superior vena cava and coronary sinus. Thus, stress and strain on the guide catheter 110 from being bent relative to the pre-curve may be alleviated. In an example, markings on the guide catheter 100 may be referenced to align the pre-curve with the anatomy. For example, markings such as markings 186 ( FIG. 6B ) may be visually read or tactilely felt to facilitate proper orientation of the pre-curve. In an example, the pre-curve of the pre-curved guide catheter 100 may be directed by aligning the markings on the pre-curved guide catheter 100 so that the pre-curve of the pre-curved guide catheter 100 faces in the desired direction. The markings can be aligned with the plane in which the pre-curve of the pre-curved guide catheter 100 is prone to unfold.

[0138] In operation 410, an insertion device may be inserted into the guide catheter to position the anatomical implant in the target area. For example, balloon catheter 200 (FIGS. 4B and 6A) may be inserted into guide catheter 100. In an example, operation 410 may be performed simultaneously with operation 406. Balloon catheter 200 may be inserted into coronary sinus 176 such that flow modification device 202 is positioned within coronary sinus 176 in a collapsed or undeployed state.

[0139] In operation 412, an anatomical implant, such as flow modification device 202 (FIG. 6A), may be positioned within the target area using an insertion tool. In an example, the flow modification device may be used to treat angina. Guide catheter 100 may be retracted from balloon catheter 200 to expose flow modification device 202.

[0140] In operation 414, the flow modification device 202 may be expanded to fit the desired anatomical features. In an example, the flow modification device 202 may be expanded to fit the coronary sinus. In an example, the balloon 210 may be expanded through the use of pressurized gas or air. The positioning and size of the flow modification device 202 may be verified using contrast injected through the guide catheter 100.

[0141] In operation 416, the expansion device used to expand flow modification device 202 may be collapsed and withdrawn from flow modification device 202. Balloon 210 may be deflated, such as by discontinuing the application of pressurized gas or air. Balloon catheter 200 may be pulled proximally into guide catheter 100, away from flow modification device 202.

[0142] In operation 418, the balloon 210 may be prevented from invaginating the guide catheter 100 using any of the features described herein. For example, an enlarged or reinforced tip 106 may be used to prevent invagination. An enlarged tip, such as the flared tip 250 (FIG. 7A) and the funnel tip 290 (FIG. 10), may have an enlarged diameter and allow the balloon 210 to enter the guide catheter 100 without pushing against the distal-most end of the guide catheter 100. An enlarged tip, such as the prolapse tip 260 (FIG. 8A), may provide the tip 106 with reinforcement to resist invagination. An enlarged tip, such as the balloon tip 270 (FIG. 9A), may be expanded, such as via inflation, to overcome invagination or resist the tendency to invaginate.

[0143] In operation 420, the insertion device may be withdrawn from the flow modification device. For example, balloon catheter 200 may be withdrawn from flow modification device 202 after the proximal-most portion of balloon 210 is within guide catheter 100. Withdrawing the insertion device may involve retracting the insertion device into the guide catheter, which may be advanced forward into the guide catheter.

[0144] In operation 422, the guide catheter may be prevented from entering the flow modification device. In particular, the guide catheter 100 may be prevented from entering the restricted portion 208 of the flow modification device 202. For example, an enlarged tip of the guide catheter 100 described herein may prevent the guide catheter 100 from entering the restricted portion 208. An enlarged tip, such as the flared tip 250 (FIG. 7A) and the funnel tip 290 (FIG. 10), may have an enlarged diameter and may prevent the tip 106 from entering the restricted portion 208. An enlarged tip, such as the prolapse tip 260 (FIG. 8A), may be shaped to press against the restricted portion 208 and prevent entry therein. An enlarged tip, such as the balloon tip 270 (FIG. 9A), may be expanded, such as via inflation, to prevent the tip 106 from entering the restricted portion 208.

[0145] In operation 424, the insertion device may be withdrawn from the patient. For example, the balloon catheter 200 may be withdrawn from the guide catheter 100.

[0146] The guide catheter and guidewire may be withdrawn from the patient in operation 426. Guide catheter 100 may be withdrawn from the neck simultaneously with guidewire 213, or alternatively.

[0147] In operation 428, the access point within the patient may be closed, leaving the implanted medical device within the anatomy.

[0148] (Example) Example 1 is a guide catheter for cannulating the coronary sinus from the superior vena cava, the guide catheter comprising a flexible elongate shaft having a proximal portion and a pre-shaped distal portion, the pre-shaped distal portion comprising a proximal straight zone, a proximal curved zone extending from the proximal straight zone along a first curved path, a distal straight zone extending from the proximal curved zone along a straight path, and a distal curved zone extending from the distal straight zone along a second curved path, and a distal tip extending from the distal curved zone.

[0149] In Example 2, the subject matter of Example 1 optionally includes the pre-shaped distal portion of the flexible elongate shaft having a size and shape selected such that the pre-shaped distal portion of the flexible elongate shaft is supported against the wall of the superior vena cava when locating the coronary sinus ostium at its distal tip.

[0150] In Example 3, the subject matter of any one or more of Examples 1-2 optionally includes the proximal curved zone having a variable radius of curvature.

[0151] In Example 4, the subject matter of Example 3 optionally includes, wherein the proximal curve zone comprises a first segment and a second segment.

[0152] In Example 5, the subject matter of any one or more of Examples 3-4 optionally includes the proximal curved zone comprising a first segment extending from the proximal straight zone along a first curved trajectory having a radius of curvature of approximately 794 millimeters ± 5 millimeters.

[0153] In Example 6, the subject matter of any one or more of Examples 4-5 optionally includes the proximal curved zone comprising a second segment extending from the first segment along a second curved trajectory having a radius of curvature of approximately 219 millimeters ± 5 millimeters.

[0154] In Example 7, the subject matter of any one or more of Examples 1-6 optionally includes, wherein the distal straight zone has a length of about 32.5 millimeters ± 5 millimeters.

[0155] In Example 8, the subject matter of any one or more of Examples 1-7 optionally includes the distal curved zone having a variable radius of curvature.

[0156] In Example 9, the subject matter of Example 8 optionally includes wherein the distal curved zone comprises a first segment, a second segment, a third segment, a fourth segment, and a fifth segment.

[0157] In Example 10, the subject matter of any one or more of Examples 8-9 optionally includes the distal curved zone comprising a first segment extending from the distal straight zone along a first curved trajectory having a radius of curvature of approximately 71 millimeters ± 5 millimeters.

[0158] In Example 11, the subject matter of Example 10 optionally includes wherein the distal curved zone comprises a second segment extending from the first segment along a second curved trajectory having a radius of curvature of approximately 26 millimeters ± 5 millimeters.

[0159] In Example 12, the subject matter of Example 11 optionally includes wherein the distal curved zone comprises a third segment extending from the second segment along a third curved trajectory having a radius of curvature of approximately 36 millimeters ± 5 millimeters.

[0160] In Example 13, the subject matter of Example 12 optionally includes wherein the distal curved zone comprises a fourth segment extending from the third segment along a fourth curved trajectory having a radius of curvature of approximately 68 millimeters ± 5 millimeters.

[0161] In Example 14, the subject matter of Example 13 optionally includes wherein the distal curved zone comprises a fifth segment extending from the fourth segment along a fifth curved trajectory having a radius of curvature of approximately 126 millimeters ± 5 millimeters.

[0162] In Example 15, the subject matter of any one or more of Examples 1-14 optionally includes the pre-shaped distal portion comprising a plurality of rigid portions, each of the plurality of rigid portions having a different level of flexibility.

[0163] In Example 16, the subject matter of Example 15 optionally includes wherein the plurality of rigid portions comprises a first rigid portion having a first tip extending along a trajectory that forms a first angle of about 10 degrees ± 0.5 degrees with the proximal linear zone.

[0164] In Example 17, the subject matter of Example 16 optionally includes, wherein the first rigid portion has a length of about 485 millimeters and a durometer of about 72D±5D.

[0165] In Example 18, the subject matter of any one or more of Examples 16-17 optionally includes the plurality of rigid portions comprising a second rigid portion having a second tip extending along a trajectory that forms a second angle of approximately 28 degrees ± 0.5 degrees with the proximal linear zone.

[0166] In Example 19, the subject matter of Example 18 optionally includes, wherein the second rigid portion has a length of about 50 millimeters and a durometer of about 63D±5D.

[0167] In Example 20, the subject matter of any one or more of Examples 18-19 optionally includes the plurality of rigid portions comprising a third rigid portion having a third tip extending along a trajectory that forms a third angle of approximately 87 degrees ± 0.5 degrees with the proximal linear zone.

[0168] In Example 21, the subject matter of Example 20 optionally includes, wherein the third rigid portion has a length of about 35 millimeters and a durometer of about 55D±5D.

[0169] In Example 22, the subject matter of any one or more of Examples 20-21 optionally includes the plurality of rigid portions comprising a fourth rigid portion having a fourth tip extending along a trajectory that forms a fourth angle of approximately 62 degrees ± 0.5 degrees with the proximal linear zone.

[0170] In Example 23, the subject matter of Example 22 optionally includes, wherein the fourth rigid portion has a length of about 38 millimeters and a durometer of about 35D±5D.

[0171] In Example 24, the subject matter of any one or more of Examples 15-23 optionally includes, wherein the distal tip has a length of about 2 millimeters and a durometer of about 25D±5D.

[0172] In Example 25, the subject matter of any one or more of Examples 1-24 optionally includes a joint connected to the proximal end of the proximal portion, the joint including indicia indicating the plane of curvature of the pre-shaped distal portion.

[0173] In Example 26, the subject matter of Example 25 optionally includes the indicia comprising a protrusion describing a direction of pre-curvature of the pre-shaped distal portion, the protrusion comprising an elongate body curved in a direction in which the pre-shaped distal portion is curved.

[0174] Example 27 is a guide catheter for delivering an expandable flow modification device to a cardiac passageway, the guide catheter comprising a flexible elongate shaft having a proximal portion with a coupling for receiving an insertion tool and a distal portion with a distal tip, the distal tip having an enlarged tip to prevent the flexible elongate shaft from passing through the expandable flow modification device.

[0175] In Example 28, the subject matter of Example 27 optionally includes, wherein the flexible elongate shaft has a diameter of about 3.0 millimeters.

[0176] In Example 29, the subject matter of any one or more of Examples 27-28 optionally includes wherein the enlarged tip comprises a flared tip.

[0177] In Example 30, the subject matter of any one or more of Examples 28-29 optionally includes, wherein the flared tip extends to a length of about 2 millimeters and has a maximum diameter of about 3.3 millimeters.

[0178] In Example 31, the subject matter of any one or more of Examples 27-30 optionally includes wherein the enlarged tip comprises a funnel-shaped tip.

[0179] In Example 32, the subject matter of Example 31 optionally includes, wherein the funnel-shaped tip extends to a length of about 10 millimeters to about 20 millimeters and has a maximum diameter of about 3.3 millimeters.

[0180] In Example 33, the subject matter of any one or more of Examples 28-32 optionally includes the enlarged tip comprising an escape tip.

[0181] In Example 34, the subject matter of Example 33 optionally includes, wherein the escape tip comprises a length of the flexible elongate shaft folded radially outward onto the flexible elongate shaft.

[0182] In Example 35, the subject matter of Example 34 optionally includes a length of the flexible elongate shaft that is folded radially outwardly forming an oblique angle with a central axis of the flexible elongate shaft.

[0183] In Example 36, the subject matter of any one or more of Examples 34-35 optionally includes that the escape tip can be straightened to align with the flexible elongate shaft and retracted to contact the flexible elongate shaft.

[0184] In Example 37, the subject matter of any one or more of Examples 27-36 optionally includes the dilating tip comprising a balloon tip.

[0185] In Example 38, the subject matter of Example 37 optionally includes the balloon tip comprising a length of flexible elongate shaft that is expandable.

[0186] In Example 39, the subject matter of Example 38 optionally includes the flexible elongate shaft having a fluid passage extending internally through at least a portion of the flexible elongate shaft and connecting to the air space within the balloon tip.

[0187] In Example 40, the subject matter of any one or more of Examples 28-39 optionally includes a retraction sheath, the retraction sheath being slidable along the flexible elongate shaft to collapse the dilator tip.

[0188] Example 41 is a method for retrieving a balloon catheter from a deployed medical device, the method including extending a delivery device from a guide catheter, positioning a flow modification device using the delivery device, expanding the flow modification device using a balloon connected to the delivery device, deflating the balloon, pulling the delivery device proximally into the guide catheter to move the balloon away from the flow modification device, and using an enlarged distal tip of the guide catheter to prevent the guide catheter from becoming lodged in the flow modification device.

[0189] In Example 42, the subject matter of Example 41 optionally includes using an enlarged distal tip of the guide catheter to prevent the guide catheter from becoming lodged in the flow modification device includes engaging a flared tip defining the enlarged distal tip with a constricted portion of the flow modification device.

[0190] In Example 43, the subject matter of Example 42 optionally includes using a retraction sheath to collapse the flared tip during insertion of the guide catheter.

[0191] In Example 44, the subject matter of any one or more of Examples 41-43 optionally includes using an enlarged distal tip of the guide catheter to prevent the guide catheter from becoming lodged in the flow modification device, including engaging a funnel-shaped tip defining the enlarged distal tip with a narrowed portion of the flow modification device.

[0192] In Example 45, the subject matter of Example 44 optionally includes a length of the funnel tip that exceeds a diameter of the guide catheter.

[0193] In Example 46, the subject matter of any one or more of Examples 41-45 optionally includes using an enlarged distal tip of the guide catheter to prevent the guide catheter from becoming lodged in the flow modification device, including engaging an escape tip defining the enlarged distal tip with a narrowed portion of the flow modification device.

[0194] In Example 47, the subject matter of Example 46 optionally includes forming a prolapse tip by frictionally engaging the guide catheter with a surrounding surface, causing the formation of a prolapse tip.

[0195] In Example 48, the subject matter of any one or more of Examples 41-47 optionally includes using an enlarged distal tip of the guide catheter to prevent the guide catheter from becoming lodged in the flow modification device, including engaging a balloon tip defining the enlarged distal tip with a narrowed portion of the flow modification device.

[0196] In Example 49, the subject matter of Example 48 optionally includes temporarily inflating the balloon tip before engaging the balloon tip with the constricted portion of the flow modification device.

[0197] In Example 50, the subject matter of any one or more of Examples 41-49 optionally includes using an enlarged distal tip to prevent the balloon from collapsing the guide catheter.

[0198] In Example 51, the subject matter of Example 50 optionally includes that using the enlarged distal tip to prevent the balloon from collapsing the guide catheter includes guiding the balloon into the guide catheter using a flared tip that defines the enlarged distal tip.

[0199] In Example 52, the subject matter of any one or more of Examples 50-51 optionally includes that using the enlarged distal tip to prevent the balloon from collapsing the guide catheter includes guiding the balloon into the guide catheter using a funnel-shaped tip that defines the enlarged distal tip.

[0200] In Example 53, the subject matter of any one or more of Examples 50-52 optionally includes that using an enlarged distal tip to prevent the balloon from collapsing the guide catheter includes strengthening the guide catheter with an escape tip that defines the enlarged distal tip.

[0201] In Example 54, the subject matter of any one or more of Examples 50-53 optionally includes that using an enlarged distal tip to prevent the balloon from collapsing the guide catheter includes strengthening the guide catheter with a balloon tip that defines the enlarged distal tip.

[0202] Example 55 is a method for inserting a pre-curved guide catheter into an anatomical passage, the method including inserting the pre-curved guide catheter into the anatomical passage and orienting the pre-curve of the pre-curved guide catheter to conform to the shape of the anatomical passage.

[0203] In Example 56, the subject matter of Example 55 optionally includes orienting the pre-curve of the pre-curved guide catheter to match the shape of the anatomical passageway includes aligning markings on the pre-curved guide catheter so that the pre-curve of the pre-curved guide catheter faces in the desired direction to extend.

[0204] In Example 57, the subject matter of Example 56 optionally includes aligning the markings on the pre-curved guide catheter to face in a direction in which the pre-curve of the pre-curved guide catheter is desired to extend, including orienting the markings in a plane in which the pre-curve of the pre-curved guide catheter is intended to extend.

[0205] In Example 58, the subject matter of any one or more of Examples 55-57 optionally includes inserting the pre-curved guide catheter into the anatomical passageway including positioning a proximal straight zone of the pre-curve within the superior vena cava of the heart, positioning the proximal curved zone of the pre-curve adjacent to an outlet of the superior vena cava of the heart, positioning a distal straight zone of the pre-curve within the right atrium of the heart, and positioning a distal curved zone of the pre-curve within the coronary sinus of the heart.

[0206] In Example 59, the subject matter of Example 58 optionally includes, wherein the proximal curvature zone comprises two segments with different curvatures.

[0207] In Example 60, the subject matter of any one or more of Examples 58-59 optionally includes, wherein the distal curved zone comprises five segments with different curvatures.

[0208] Example 61 is a system for implanting a flow correction device within the cardiac vasculature, the system comprising: a flow correction device comprising a tubular body having a first opening located at a first end of the tubular body, a second opening located at a second end of the tubular body, and a reduced diameter portion positioned between the first opening and the second opening; and a guide catheter having a flexible elongate shaft, the flexible elongate shaft having a proximal portion with a coupling for receiving an insertion tool and a distal portion with a distal tip, the distal tip having an enlarged tip to prevent the flexible elongate shaft from passing through the flow correction device.

[0209] In Example 62, the subject matter of Example 61 optionally includes the tubular body being configured to expand from a first configuration in which the first opening, the second opening, and the reduced diameter portion have a first diameter to a second configuration in which the first opening, the second opening, and the reduced diameter portion are larger than the first diameter.

[0210] In Example 63, the subject matter of Example 62 optionally includes a distal portion of the flexible elongate shaft sized to be smaller than the reduced diameter portion in the second configuration, and an enlarged tip of the distal portion sized to be larger than the reduced diameter portion in the second configuration.

[0211] In Example 64, the subject matter of any one or more of Examples 62-63 optionally includes the tubular body increasing in diameter from the reduced diameter portion to the first opening and the second opening, and the enlarged tip being shaped to conform to the shape of the tubular body between the reduced diameter portion and one of the first opening and the second opening.

[0212] In Example 65, the subject matter of any one or more of Examples 62-64 optionally includes, in the second configuration, the tubular body having a first opening, a first flared portion extending from the first opening, a reduced diameter portion, a second flared portion extending from the reduced diameter portion, and a second opening.

[0213] In Example 66, the subject matter of Example 65 optionally includes the tubular body further comprising, in the second configuration, a first conical portion positioned between the first opening and the first flared portion, and a second conical portion positioned between the second opening and the second flared portion.

[0214] In Example 67, the subject matter of any one or more of Examples 65-66 optionally includes the reduced diameter portion comprising a curved portion of the tubular body in the second configuration.

[0215] In Example 68, the subject matter of any one or more of Examples 65-67 optionally includes the enlarged tip being shaped to fit over the first or second flared portion.

[0216] In Example 69, the subject matter of any one or more of Examples 61-68 optionally includes wherein the enlarged tip comprises a flared tip.

[0217] In Example 70, the subject matter of any one or more of Examples 61-69 optionally includes the enlarged tip comprising a funnel-shaped tip.

[0218] In Example 71, the subject matter of any one or more of Examples 61-70 optionally includes the enlarged tip comprising an escape tip.

[0219] In Example 72, the subject matter of any one or more of Examples 61-71 optionally includes the dilating tip comprising a balloon tip.

[0220] In Example 73, the subject matter of any one or more of Examples 61-72 optionally includes a retraction sheath slidable along the flexible elongate shaft to collapse the dilator tip.

[0221] In Example 74, the subject matter of any one or more of Examples 61-73 optionally includes a balloon catheter, the balloon catheter having an elongate shaft and an inflatable balloon configured to be inserted into the tubular body of the flow modification device in a collapsed state, the inflatable balloon having a first end configured to expand a first opening of the tubular body and a second end configured to expand a second opening of the tubular body, and at least one of the first end and the second end of the inflatable balloon is configured to engage the enlarged tip of the guide catheter and urge the inflatable balloon in a deflated state back into the guide catheter.

[0222] In Example 75, the subject matter of any one or more of Examples 61-74 optionally includes the enlarged tip of the guide catheter configured to engage the inflatable balloon in a non-axial direction.

[0223] In Example 76, the subject matter of any one or more of Examples 61-75 optionally includes an enlarged tip of the guide catheter that is positioned at an angle relative to the flexible elongate shaft of the guide catheter and has a conical wall so that, in an inflated state, it abuts the first or second end of the inflatable balloon.

[0224] In Example 77, the subject matter of any one or more of Examples 61-75 optionally includes the enlarged tip of the guide catheter having a rounded leading edge configured to engage the first or second end of the inflatable balloon via an arcuate contact area.

[0225] In Example 78, the subject matter of any one or more of Examples 61-77 optionally includes an enlarged tip of the guide catheter that reinforces the guide catheter and resists an inward force generated by the inflatable balloon being pulled into the guide catheter in a deflated state, the inward force tending to cause the guide catheter to collapse.

[0226] Each of these non-limiting examples can stand on its own or can be combined in various permutations or combinations with one or more of the other examples.

[0227] (Miscellaneous notes) The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are also referred to herein as "examples." Such examples may include elements in addition to those shown or described. However, the inventors also contemplate examples in which only those elements shown or described therein are provided. Furthermore, the inventors also contemplate examples using any combination or permutation of those illustrated or described elements (or one or more aspects thereof), either with respect to the particular example (or one or more aspects thereof) shown or described herein, or with respect to other examples (or one or more aspects thereof).

[0228] In the event of a conflicting usage between this document and any document so incorporated by reference, the usage in this document shall control.

[0229] The terms "a" or "an" are used herein, as is common in patent documents, to include "one or more than one," independently of any other instance or usage of "at least one" or "one or more." The term "or" is used herein to refer to a non-exclusive or, unless otherwise indicated, such that "A or B" includes "A but not B," "B but not A," and "A and B." The terms "including" and "in which" are used herein as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, i.e., systems, devices, articles, compositions, formulations, or processes that include elements in addition to those listed after such terms in a claim are still considered to fall within the scope of that claim. Also, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels and are not intended to impose numerical requirements on their objects.

[0230] The above description is intended to be illustrative, not limiting. For example, the examples described above (or one or more aspects thereof) may be used in combination with each other. Other embodiments may also be utilized by those skilled in the art upon review of the above description. The Abstract is provided to enable the reader to quickly ascertain the nature of the present technical disclosure. It should be considered with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also in the above Detailed Description, various features may be grouped together for the purpose of conciseness of the disclosure. This should not be construed as intending that any unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are herein incorporated into the Detailed Description as an example or embodiment, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full range of equivalents to which such claims are entitled.

Claims

1. 1. A guide catheter for delivering an expandable flow modification device to a cardiac passageway, comprising: the guide catheter comprises a flexible elongate shaft; The flexible elongate shaft comprises: a proximal portion including a fitting for receiving an insertion tool; a distal portion having a distal tip; Equipped with A guide catheter, wherein the distal tip comprises an enlarged tip for preventing the flexible elongate shaft from passing through the expandable flow modification device.

2. The guide catheter of claim 1 , wherein the flexible elongate shaft has a diameter of about 3.0 millimeters.

3. The guide catheter of claim 1 , wherein the enlarged tip comprises a flared tip.

4. The guide catheter of claim 3 , wherein the flared tip extends approximately 2 millimeters in length and has a maximum diameter of approximately 3.3 millimeters.

5. The guide catheter of claim 1 , wherein the enlarged tip comprises a funnel-shaped tip.

6. The guide catheter of claim 5 , wherein the funnel-shaped tip extends from about 10 millimeters to about 20 millimeters in length and has a maximum diameter of about 3.3 millimeters.

7. The guide catheter of claim 1 , wherein the enlarged tip comprises an escape tip.

8. The guide catheter of claim 7 , wherein the escape tip comprises a length of the flexible elongate shaft folded radially outwardly onto another length of the flexible elongate shaft.

9. The guide catheter of claim 8 , wherein the length of the flexible elongate shaft that is folded radially outward forms an oblique angle with a central axis of the other length of the flexible elongate shaft.

10. 9. The guide catheter of claim 8, wherein the escape tip is configured to be straightened into alignment with the other length of the flexible elongate shaft and configured to be retracted into contact with the flexible elongate shaft.

11. The guide catheter of claim 1 , wherein the enlarged tip comprises a balloon tip.

12. The guide catheter of claim 11 , wherein the balloon tip comprises a length of the flexible elongate shaft that is inflatable.

13. 13. The guide catheter of claim 12, wherein the flexible elongate shaft includes a fluid passageway extending internally through at least a portion of the flexible elongate shaft and connecting to an air space within the balloon tip.

14. The guide catheter of claim 1 , further comprising a retraction sheath, said retraction sheath being slidable along said flexible elongate shaft to collapse said dilating tip.

15. 1. A system for implanting a flow modifying device within the vasculature of the heart, the system comprising:

1. A flow modification device comprising a tubular body, the tubular body comprising: a first opening located at a proximal end of the tubular body; a second opening located at the distal end of the tubular body; and a reduced diameter portion positioned between the first opening and the second opening; a flow modification device comprising: the tubular body configured to expand from a first configuration to a second configuration, wherein in the second configuration, the first opening comprises a first diameter and the reduced diameter portion comprises a second diameter smaller than the first diameter; a guide catheter having a flexible elongated shaft; Equipped with The flexible elongate shaft comprises: a proximal portion including a fitting for receiving an insertion tool; a distal portion comprising a distal tip configured to be receivable by the first opening of the tubular body when the tubular body is in the second configuration, the distal tip comprising an enlarged tip to prevent the flexible elongate shaft from passing through the reduced diameter portion of the flow modification device when the tubular body is in the second configuration; A system comprising:

16. 16. The system of claim 15, wherein when the tubular body is in the second configuration, the individual diameters of the first and second openings are larger than when the tubular body is in the first configuration.

17. 16. The system of claim 15, wherein the distal portion of the flexible elongate shaft is sized to be smaller than the reduced diameter portion in the second configuration, and the enlarged tip of the distal portion is sized to be larger than the reduced diameter portion in the second configuration.

18. 16. The system of claim 15, wherein the tubular body increases in diameter from the reduced diameter portion to the first opening and the second opening, and the enlarged tip is shaped to conform to the shape of the tubular body between the reduced diameter portion and one of the first opening and the second opening.

19. In the second configuration, the tubular body comprises: a first flared portion extending from the first opening; and a second flared portion extending from the reduced diameter portion; and The system of claim 15, comprising:

20. The tubular body, in the second configuration, a first conical portion positioned between the first opening and the first flared portion; a second conical portion positioned between the second opening and the second flared portion; and 20. The system of claim 19, further comprising:

21. 16. The system of claim 15, wherein the reduced diameter section comprises a curved portion of the tubular body in the second configuration.

22. 20. The system of claim 19, wherein the enlarged tip is shaped to fit over the first flared portion.

23. The system of claim 15 , wherein the enlarged tip comprises a flared tip.

24. The system of claim 15 , wherein the enlarged tip comprises a funnel-shaped tip.

25. The system of claim 15 , wherein the dilation tip comprises an escape tip.

26. The system of claim 15 , wherein the dilation tip comprises a balloon tip.

27. 16. The system of claim 15, further comprising a retraction sheath, said retraction sheath slidable along said flexible elongate shaft and configured to collapse said dilator tip.

28. Further comprising a balloon catheter, the balloon catheter comprising: A long, slender shaft and an inflatable balloon configured to be inserted into the tubular body of the flow modification device when the tubular body is in the first configuration; Equipped with The inflatable balloon comprises: a first end configured to expand the first opening of the tubular body; and a second end configured to expand the second opening of the tubular body; and Equipped with 16. The system of claim 15, wherein the first end of the inflatable balloon is configured to engage the enlarged tip of the guide catheter and urge the inflatable balloon in a deflated state back into the guide catheter.

29. 30. The system of claim 28, wherein the enlarged tip of the guide catheter is configured to engage the inflatable balloon non-axially.

30. 29. The system of claim 28, wherein the enlarged tip of the guide catheter comprises a conical wall disposed at an angle relative to the flexible elongate shaft of the guide catheter such that the conical wall abuts the first end of the inflatable balloon when the inflatable balloon is in an inflated state.

31. 29. The system of claim 28, wherein the enlarged tip of the guide catheter comprises a rounded leading edge, the rounded leading edge configured to engage the first end of the inflatable balloon via an arcuate contact area.

32. 29. The system of claim 28, wherein the enlarged tip of the guide catheter is configured to reinforce the guide catheter to resist an inward force generated by the inflatable balloon being pulled into the guide catheter in the deflated state to prevent invagination of the enlarged tip.

33. The system of claim 15, wherein when the tubular body is in the second configuration, the diameter of the reduced diameter portion is larger than when the tubular body is in the first configuration.

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