Implantable medical devices and related delivery systems

The present disclosure describes medical devices comprising implantable expandable implants, such as stent-grafts. Such devices can comprise a constraining line. The constraining line can surround the proximal end of the expandable implant, and assist in positioning and deployment of the expandable implant within the body of the patient.

FIELD

The present disclosure relates generally to implantable medical devices and, more specifically, to stent-grafts removably coupled to delivery devices.

BACKGROUND

Implantable medical devices are frequently used to treat the anatomy of patients. Such devices can be permanently or semi-permanently implanted in the anatomy to provide treatment to the patient. Frequently, these devices, including stents, grafts, stent-grafts, filters, valves, occluders, markers, mapping devices, therapeutic agent delivery devices, prostheses, pumps, bandages, and other endoluminal and implantable devices, are inserted into the body at an insertion point and deployed to a treatment area using a catheter.

Typically, these implantable devices are attached to the catheter assembly and directed through the vasculature of the patient to the desired treatment area. Once the implantable device reaches the treatment area, the device is properly oriented and deployed to provide treatment. Such orientation and deployment is actuated by a physician using controls outside of the body of the patient. Accordingly, there is a need for medical devices with improved maneuverability and positioning within the vasculature of the patient.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

As used herein, “medical devices” can include, for example, stents, grafts, stent-grafts, filters, valves, occluders, markers, mapping devices, therapeutic agent delivery devices, prostheses, pumps, bandages, and other endoluminal and implantable devices that are implanted, acutely or chronically, in the vasculature or other body lumen or cavity at a treatment region.

The medical devices, support structures, coatings, and covers, described herein, can be biocompatible. As used herein, “biocompatible” means suited for and meeting the purpose and requirements of a medical device, used for long- or short-term implants or for non-implantable applications. Long-term implants are generally defined as devices implanted for more than about 30 days, while short-term implants are generally defined as devices implanted for less than about 30 days.

As used herein, “proximal” indicates a position closer to the heart of the patient, or to a portion of a device that, when implanted, is closer to the heart of the patient than another portion of the device. “Distal” indicates a position farther from the heart of the patient, or to a portion of a device that, when implanted, is farther from the heart of the patient than another portion of the device. Implanted devices having tubular or rod-like shape comprise a distal end, a distal portion, a medial portion, a proximal portion, and a proximal end moving from the end farthest from the heart to the end closest to the heart.

As used herein, a “sleeve” can include any enclosure constraining an expandable device. In various embodiments, a sleeve can comprise a sheet of material wrapped around an expandable device in a collapsed, intermediate, or treatment configuration.

As used herein, the term “constrain” means: (i) to limit expansion, occurring either through self-expansion or assisted expansion, of the diameter of an expandable implant; or (ii) to cover or surround, but not otherwise restrain, an expandable implant such as for storage or biocompatibility reasons and/or to provide protection to the expandable implant and/or the vasculature.

As used herein, “deployment” refers to the actuation of a device at a treatment site, such as for example, the release and/or removal of a sleeve from a self-expanding device to allow the device to expand. The deployment process can be in stages, such as for example, a first stage comprising the release of a sleeve to a configuration suitable to constrain the expandable device only to an intermediate configuration, and a second stage comprising the removal of the sleeve altogether from the device.

Various embodiments of the present disclosure comprise a catheter assembly configured to deliver an expandable implant to a treatment area of the vasculature of a patient. In accordance with embodiments of the disclosure, an expandable implant, such as a stent-graft, is constrained by one or more sleeves concentrically surrounding the expandable implant. The expandable implant can be maintained in a desired orientation and/or position relative to the catheter assembly by a constraining line. Benefits of expandable implants in accordance with the present disclosure can include improved maneuverability of the expandable implant within the vasculature of a patient, and improved deployment characteristics.

With initial reference toFIG. 1, a catheter assembly100in accordance with the present disclosure is illustrated. Catheter assembly100comprises a catheter shaft102. An expandable implant104is positioned at a proximal end of and removably coupled to catheter shaft102by a constraining line120. Expandable implant104is concentrically surrounded by at least one constraining sleeve, such as sleeve110.

In various embodiments, expandable implant104comprises a stent-graft. Conventional stent-grafts are designed to dilate from their delivery diameter, through a range of intermediary diameters, up to a maximum, often pre-determined functional diameter, and generally comprise one or more stent components with one or more graft members displaced over and/or under the stent.

In various embodiments, expandable implant104comprises one or more stents106. In various embodiments, stent106comprises a biocompatible material. For example, stent106can be formed from metallic, polymeric or natural materials and can comprise conventional medical grade materials such as nylon, polyacrylamide, polycarbonate, polyethylene, polyformaldehyde, polymethylmethacrylate, polypropylene, polytetrafluoroethylene, polytrifluorochlorethylene, polyvinylchloride, polyurethane, elastomeric organosilicon polymers; metals such as stainless steels, cobalt-chromium alloys and nitinol, and biologically derived materials such as bovine arteries/veins, pericardium and collagen. Stent106can also comprise bioresorbable materials such as poly(amino acids), poly(anhydrides), poly(caprolactones), poly(lactic/glycolic acid) polymers, poly(hydroxybutyrates) and poly(orthoesters). Any material that is biocompatible and provides adequate support for expandable implant104is in accordance with the present disclosure.

Stent106can comprise, for example, various configurations such as joined rings, cut tubes, wound wires (or ribbons) or flat patterned sheets rolled into a tubular form. However, any configuration of stent106that can be implanted in and provide support to the vasculature of a patient is in accordance with the present disclosure.

In various embodiments, stent106can comprise one or more anchors116. For example, one or more anchors116can be located at or near the proximal end of stent106. In such configurations, anchors116can engage and attach to the vasculature of the patient to maintain expandable implant104in a desired position within the vasculature. The use of any number and configuration of anchors116is within the scope of the present disclosure.

In various embodiments, expandable implant104comprises a graft member108. Graft member108can comprise a biocompatible material that provides a lumen for blood flow within a vasculature. For example, graft member108can comprise a composite material having a flexible matrix. In such configurations, the flexible matrix can comprise, for example, expanded polytetrafluoroethylene (ePTFE), pebax, polyester, polyurethane, fluoropolymers, such as perfouorelastomers and the like, polytetrafluoroethylene, silicones, urethanes, ultra high molecular weight polyethylene, aramid fibers, silk, and combinations thereof. Other flexible matrices can include high strength polymer fibers such as ultra high molecular weight polyethylene fibers (e.g., Spectra®, Dyneema Purity®, etc.) or aramid fibers (e.g., Technora®, etc.). Any graft member108that provides a sufficient lumen for blood flow within a vasculature is in accordance with the present disclosure.

In various embodiments, graft member108can comprise a composite material having a flexible matrix and an elastomeric component. An elastomeric component can comprise, for example, a perfluoroalkylvinylether (PAVE), such as perfluoromethylvinylether (PMVE) as described in U.S. Pat. No. 7,462,675 (hereby incorporated by reference), perfluoroethylvinylether (PEVE), or perfluoropropylvinylether (PPVE). Other biocompatible polymers which can be suitable for use in embodiments can include, but are not limited to, the group of urethanes, silicones, copolymers of silicon-urethane, styrene.isobutylene copolymers, polyisobutylene, polyethylene-co-poly(vinyl acetate), polyester copolymers, nylon copolymers, fluorinated hydrocarbon polymers and copolymers or mixtures of each of the foregoing. In such configurations, the flexible matrix is imbibed with the elastomeric component. However, any elastomeric component that is biocompatible and can be imbibed by a suitable flexible matrix is in accordance with the present disclosure.

With reference toFIG. 1, expandable implant104can be delivered to the treatment area of a patient by a catheter assembly100. In various embodiments, expandable implant104is delivered into the body of a patient via catheter shaft102. In such embodiments, expandable implant104can be collapsed and/or compressed and positioned at the proximal end of catheter shaft102. Expandable implant104can then be navigated through the body of the patient to the treatment area.

In various embodiments, expandable implant104can comprise a radially collapsed configuration suitable for delivery to the treatment area of the vasculature of a patient. Expandable implant104can be constrained in a radially collapsed configuration and mounted onto a delivery device such as catheter shaft102. The diameter of the expandable implant104in the collapsed configuration is small enough for the implant to be delivered through the vasculature to the treatment area. In various embodiments, the diameter of the collapsed configuration is small enough to minimize the crossing profile of catheter assembly100and minimize tissue damage to the patient. In the collapsed configuration, the expandable implant104can be guided by catheter shaft102through the vasculature. Once expandable implant104is in position in the treatment area of the vasculature, it can be expanded to a radially expanded configuration.

In various embodiments, expandable implant104can comprise a radially expanded configuration suitable for implanting the device in the treatment area of a patient's vasculature. In the expanded configuration, the diameter of expandable implant104can be approximately the same as the vessel to be repaired. In other embodiments, the diameter of expandable implant104in the expanded configuration can be slightly larger than the vessel to be treated to provide a traction fit within the vessel.

In various embodiments, expandable implant104can comprise a self-expandable device, such as a self-expandable stent-graft. Such devices dilate from a radially collapsed configuration to a radially expanded configuration when unrestrained. In other embodiments, expandable implant104can comprise a device that is expanded with the assistance of a secondary device such as, for example, a balloon. In yet other embodiments, catheter assembly100can comprise a plurality of expandable implants104. The use of a catheter assembly with any number of expandable implants is within the scope of the present disclosure.

Various medical devices in accordance with the disclosure comprise a sleeve or multiple sleeves. The sleeve or sleeves can constrain an expandable implant device in a collapsed configuration for endoluminal delivery of the implant to a treatment portion of the vasculature of a patient. For example, as illustrated inFIG. 1, catheter assembly100comprises sleeve110. Sleeve110surrounds and constrains expandable implant104to a reduced diameter.

After delivery of the expandable implant to the treatment portion of the vasculature of the patient, the sleeve or sleeves can be unconstrained in order to allow the expandable implant to expand to its functional diameter and achieve the desired therapeutic outcome. In various embodiments, the sleeve or sleeves can remain implanted while not interfering with the expandable implant. In other embodiments, the sleeve or sleeves can be removed from the body of the patient after successful deployment of the expandable implant.

In various embodiments, sleeves such as sleeve110can be formed from a sheet of one or more materials wrapped or folded about the expandable implant. While the illustrative embodiments herein are described as comprising one or more tubular sleeves, sleeves of any non-tubular shape that corresponds to an underlying expandable implant or that are otherwise appropriately shaped for a given application are also within the scope of the present disclosure.

In various embodiments, sleeves are formed by wrapping or folding the sheet of material(s) such that two parallel edges of the sheet are substantially aligned. Said alignment may or may not be parallel to or coaxial with the catheter shaft of a catheter assembly. In various embodiments, the edges of the sheet of material(s) do not contact each other. In other embodiments the edges of the sheet of material(s) contact each. Any manner of forming a sleeve from a sheet of material is within the scope of the present disclosure.

In various embodiments, sleeves comprise materials similar to those used to form a graft member. For example, a precursor flexible sheet used to make the sleeve can be formed from a flattened, thin wall ePTFE tube. The thin wall tube can incorporate “rip-stops” in the form of longitudinal high strength fibers attached or embedded into the sheet or tube wall.

The sheet of material(s) used to form the sleeve(s) can comprise a series of openings, such that the openings extend from one edge of the sheet to the other. In such configurations, a coupling member can be woven or stitched through the series of openings in the sheet of material(s), securing each of the two edges together and forming a tube. For example, inFIG. 1, catheter assembly100comprises a coupling member112that engages with a plurality of holes114and secures the edges of sleeve110such that sleeve110maintains expandable implant104in a reduced diameter.

In various embodiments, when the expandable implant is in position within the vasculature, coupling member112can be disengaged from the sleeve or sleeves from outside of the body of the patient, which allows the sleeve(s) to open and the expandable implant to expand. As discussed above, the expandable implant can be self-expanding, or the implant can be expanded by a device, such as a balloon.

Coupling member112can comprise, for example, a woven fiber. In other embodiments, the coupling member can comprise a monofilament fiber. Any type of string, cord, thread, fiber, or wire that is capable of maintaining a sleeve in a tubular shape is within the scope of the present disclosure.

The coupling member or members can be disengaged from the sleeve or sleeves by a mechanical mechanism operated from outside of the body of the patient. For example, coupling member112can be disengaged by applying sufficient tension to coupling member112. In another example, a dial or rotational element of a catheter handle can be attached to coupling member112outside of the body. Rotation of the dial or rotational element can provide sufficient tension to, displace and disengage coupling member112.

In various embodiments, disengaging a single coupling member that closes a single sleeve from the sleeve allows the expandable device to be fully expanded. For example, with reference toFIG. 1catheter assembly100can be used to deliver an expandable implant104to a treatment area of a vasculature. In such configurations, sleeve110circumferentially surrounds expandable implant104and constrains it to a collapsed configuration. Once expandable implant104is in position relative to the treatment area, coupling member112is disengaged from sleeve110and sleeve110is released, allowing expandable implant104to expand from a collapsed configuration to a larger diameter.

In various embodiments, catheter assembly100further comprises a constraining line120. Constraining line120can, for example, assist in securing expandable implant104to catheter shaft102. In various embodiments, constraining line120can be positioned on or near the proximal end of expandable implant104. In other embodiments, constraining line120can be positioned at or near the distal, or at any position between the proximal and distal end, of expandable implant104. Constraining line120can interact with expandable implant104and assist in maintaining a desired position and orientation of expandable implant104in relation to catheter shaft102. In such embodiments, constraining line120can improve maneuverability of expandable implant104relative to the treatment area of the patient by, for example, allowing an operator to displace and orient expandable implant104within the vasculature of a patient even after the implant has been partially or fully expanded. Further, constraining line120can constrain and prevent the proximal end of expandable implant104from contacting and/or engaging the vasculature until full and final deployment is desired.

With reference toFIG. 2, in various embodiments, constraining line120can interact with stent106. Stent106can comprise a stent pattern222having straight segments224and apices226. In various embodiments, constraining line120can be woven through alternating straight segments224and/or alternating apices226around the circumference of expandable implant104at the proximal end and perpendicular to a longitudinal axis of expandable implant104. In other embodiments, constraining line can be woven through straight segments224and apices226at an angle relative to the longitudinal axis of expandable implant104. However, constraining line120can interact with expandable implant104in any manner that will allow constraining line120to maintain expandable implant104in a desired position and orientation relative to catheter shaft102.

In various embodiments, expandable implant104is inserted into the vasculature of the patient in a collapsed configuration, wherein expandable implant104is surrounded by sleeve110and held in a desired position relative to catheter shaft102by constraining line120. Expandable implant104is then directed to a treatment area of the patient. Upon reaching the treatment area, the implant is deployed. In various embodiments, deployment of expandable implant104comprises removing sleeve110and removing constraining line120from expandable implant104.

In various embodiments, constraining line120can include or form a loop230. In such embodiments, constraining line120can interact with or otherwise extend through the loop230to form a slip knot and travel from the proximal end of expandable implant104to the outside of the body of the patient. Alternatively, loop230can comprise an end loop, such that when constraining line120passes through loop230, it forms a slip knot. In such embodiments, constraining line120comprises a line or wire looped into an end loop230, thereby creating two segments. Both segments pass through loop230to form the slip knot, and then travel back along the length of the delivery device and outside of the patient. The resulting slip knot can extend about and releasably restrain the proximal end of the expandable implant104axially and/or radially with respect to the catheter shaft102.

Referring toFIG. 2, to release constraining line120from expandable implant104, the operator can release one of the segments of constraining line120and provide tension to the other segment in direction232. By pulling the non-released segment of constraining line120, the released segment can travel in the direction234, through catheter shaft102, unwind along the segment of expandable implant104through which it was woven, then travel back through and exit from catheter shaft102. Although described in relation to a single constraining line120and loop230, any number of constraining lines120and loops230are within the scope of the present disclosure.

For example, catheter assembly100can further comprise a catheter handle, and one or more segments of constraining line120can be removably coupled to the catheter handle. In such embodiments, the catheter handle can comprise a release button that, when activated, releases one segment of constraining line120.

As illustrated inFIGS. 3A, 3B, 4A, and 4B, constraining line120can maintain expandable implant104in a desired position relative to catheter shaft102and can extend about and constrain the proximal end of the expandable implant104relative to the catheter shaft102.

For example, with reference toFIGS. 3A and 3B, expandable implant104can be positioned concentrically around catheter shaft102. As illustrated inFIG. 3A, constraining line120can surround the proximal end of expandable implant104, pass through loop230to form the slip knot, and travel along the outside surface of catheter shaft102. As illustrated inFIG. 3B, after passing through loop230, constraining line120can pass through access hole328in catheter shaft102and travel along the interior of catheter shaft102to the outside of the body of the patient.

With reference toFIGS. 4A and 4B, expandable implant104can be positioned adjacent and parallel to catheter shaft102. For example, as illustrated inFIG. 4A, constraining line120can surround the proximal end of expandable implant104, pass through loop230to form the slip knot, and travel along the outside surface of catheter shaft102. In various embodiments, catheter shaft102can comprise one or more retainers430, which maintain constraining line120in a desired position and orientation relative to catheter shaft102. As illustrated inFIG. 4B, after passing through loop230, constraining line120can pass through access hole328in catheter shaft102and travel along the interior of catheter shaft102to the outside of the body of the patient. Although the above embodiments are described in detail, any configuration of constraining line120, catheter shaft102, and expandable implant104is within the scope of the present disclosure.

In various embodiments, constraining line120can assist in deployment of expandable implant104. For example, coupling member112can be removed to allow sleeve110to open to its unconstrained diameter. Expandable implant104can then be expanded to its expanded configuration. In such embodiments, it may be desirable to remove sleeve110by applying tension to and consequently retracting sleeve110from the body of the patient. However, the tension applied to sleeve110can cause portions of stent106to collapse, become displaced, or distort. For example, when tension is applied, the proximal end of stent106can be pulled towards the distal end, displacing and/or deforming the proximal end. In various embodiments, constraining line120can be configured to resist such tension and maintain the proximal end in a desired position and location relative to catheter shaft102.

In other embodiments, catheter assembly100can comprise multiple sleeves. In such configurations, a first sleeve constrains expandable implant104in a collapsed configuration. By removing and/or activating a first coupling member, the first sleeve can be removed and expandable implant104can expand to a configuration having a larger diameter than in the collapsed configuration.

In such embodiments, expandable implant104can be expanded from the collapsed configuration to the intermediate configuration once expandable implant104has been delivered near the treatment area of the vasculature of a patient. The intermediate configuration can, among other things, assist in properly orienting and locating the expandable implant within the treatment area of the vasculature.

Catheter assembly100can further comprise a balloon. In such embodiments, the balloon can assist in final deployment of expandable implant104by, for example, being inflated within expandable implant104. With sufficient inflation, the balloon can force stent106to fully expand against the walls of the vasculature. In embodiments that utilize anchors116, the balloon can assist anchors116in engaging with the vasculature by forcing anchors116against the vessel walls.

In various embodiments, various components of the devices disclosed herein are steerable. For example, during deployment at a treatment site, one or more of the elongated segments can be configured with a removable steering system that allows an end of the elongated segment to be biased or directed by a user. A removable steering system in accordance with various embodiments can facilitate independent positioning of an elongated segment and can provide for the ability of a user to accomplish any of the types of movements previously described, such as longitudinal movement, rotational movement, lateral movement, or angular movement.

Likewise, numerous characteristics and advantages have been set forth in the preceding description, including various alternatives together with details of the structure and function of the devices and/or methods. The disclosure is intended as illustrative only and as such is not intended to be exhaustive. It will be evident to those skilled in the art that various modifications can be made, especially in matters of structure, materials, elements, components, shape, size and arrangement of parts including combinations within the principles of the disclosure, to the full extent indicated by the broad, general meaning of the terms in which the appended claims are expressed. To the extent that these various modifications do not depart from the spirit and scope of the appended claims, they are intended to be encompassed therein.