The present disclosure relates to expandable, intraluminal devices for use within a body passageway or duct and, more particularly, to stent devices including one or more portions configured to flare radially outwardly relative to other portions of the stent device for positioning, improving subsequent access to the stent device, and/or anchoring the stent device within the body passageway or duct.
A common method for treating stenosed or aneuryzed vessels or other blocked passageways is to utilize an expandable prosthesis or stent device. The prosthesis or stent device is an expandable structure configured to be deployed in the vessel or passageway in an expanded state to maintain patency or continuity of the vessel or passageway. Conventional stents are often formed from a framework of interconnecting members or tines. Many stent designs are known and can include combinations of different types of framing structures, such as helical coils, meshes, lattices, or interconnected rings. Such framing structures can be made from, for example, stainless steel and/or cobalt chromium. Some stents are formed from shape memory materials, such as a nickel-titanium alloy (e.g., NITINOL), which can be biased to a deployed position or can be configured to adopt the deployed position after being heated above a selected temperature, such as body temperature. Conventional stents can be covered or uncovered. The cover can be constructed from a biocompatible material, such as polytetrafluoroethylene (PTFE) or expanded polytetrafluoroethylene (ePTFE). In one common design, a stent can include a series of cylindrical rings aligned in a series along a central longitudinal axis. The rings can be fixedly secured to one another by a plurality of interconnecting members, such as longitudinally extending struts.
In many surgical procedures, a stent device is configured to be delivered to a target site, expanded, and affixed in place. For example, in a fenestrated endovascular aneurysm repair (FEVAR) procedure, a number of stents may be placed within pre-formed openings or fenestrations in a main body implant or endoprosthesis to create a connection between the main body implant and target branch vessels or conduits. In vascular applications, covered stents can protrude into an aortic main body implant or endoprosthesis for a few millimeters. Once deployed and affixed in place, the stent(s) create an enclosed lumen space for passage of blood from the main body implant or endoprosthesis to the target vessels. The stent(s) can also provide increased reinforcement of the vessel wall, in order to maintain the cleared lumen or passageway.
Stent devices can include regions that can be selectively post dilated to a larger diameter to anchor the stent at a desired or target location within the vessel. For example, during FEVAR procedures or stenting for visceral artery occlusive disease, portions of the stent extending into the aorta may be made to flare outwardly to help maintain positioning of the stent device in the aorta and arteries, and to create unfettered access to the stented vessel for future cannulation. In order to provide such outwardly flarable portions, it is common practice for the surgeon to introduce a second balloon catheter into the stent after deployment of the stent within the body lumen. The second balloon catheter can be expanded to flare the end of the stent. Thus, deployment of a conventional flared stent is a two part process. First, the stent is deployed with a first balloon catheter. Second, a portion of the stent is flared using a second balloon catheter.
In some instances, the outwardly flarable portions of the stent can also include projecting structures for enhancing engagement between the stent device and the vessel wall. For example, conventional protruding structures can include deployable hooks, fasteners, or barbs configured to protrude from a body of the stent when the stent is deployed. As the stent flares radially outwardly, the protruding structures can be brought into contact with the vessel wall to anchor the stent device in place.
For stents formed from shape memory materials, the stent body may be biased to adopt or conform to an outwardly flarable orientation either upon deployment of the stent in the body lumen or after the stent body increases in temperature above a preselected temperature. In some instances, the outwardly flaring portions of the device can also include projecting, pointed, or sharpened structures for enhancing engagement between the device and the vessel wall. For example, conventional protruding structures can include deployable hooks, fasteners, or barbs configured to protrude from a body of the device when the device is deployed. As the device deploys radially outwardly, due to an internal bias of the shape memory material, the protruding structures can be brought into contact with the vessel wall to anchor the stent device in place. In some instances, these outwardly flaring portions can be supported by a support strut that restricts the flared portion from retracting or collapsing away from the desired position.
There is a need for new stent designs, which facilitate easy insertion and deployment, and which provide unfettered post deployment access. For example, the stent devices disclosed herein can include portions configured to flare radially outwardly, without requiring additional manipulation of the stent device following deployment. Such stent devices may be referred to as “auto-flaring” or “self-flaring” stent devices. In contrast, current stent devices typically require using a secondary device, such as a second balloon catheter, to flare portions of the stent, which substantially adds to the cost and time required for different procedures. There is also always a need for less complex stent designs which reduce manufacturing costs. The stent devices disclosed herein are designed to provide such benefits.
According to an aspect of the disclosure, a stent device includes: at least one radially expandable body portion extending along a longitudinal axis of the stent device defining a lumen; and at least one outwardly flarable portion connected to the body portion. The outwardly flarable portion includes at least one radially expandable ring connected to the body portion and at least one flaring connector connected to the at least one ring configured to cause a crown of the at least one ring to automatically flare radially outwardly relative to other portions of the ring upon radial expansion of the body portion so as to form a flared crown. Once the flarable crown is in the deployed configuration, the flaring connector acts as a support strut that keeps the flared crown in the flared position and prevents it from collapsing or retracting.
According to another aspect of the disclosure, a method of deploying a stent device includes a step of preparing a stent device for a surgical procedure. The stent device includes: at least one radially expandable body portion extending along a longitudinal axis of the stent device defining a lumen; and at least one outwardly flarable portion connected to the body portion, the outwardly flarable portion including at least one radially expandable ring connected to the body portion; and at least one flaring connector connected to the at least one ring configured to cause a crown of the at least one ring to automatically flare radially outwardly relative to other portions of the ring upon radial expansion of the body portion so as to form a flared crown and a support strut that inhibits the flared crown from retracting. The method further includes steps of advancing the stent device, with the flaring connector in a retracted position, through a body lumen to a deployment location, and once in the deployment location, deploying the stent device, thereby allowing the body portion and at least one ring of the stent device to expand radially outwardly.
Examples of the present disclosure will now be described in the following numbered clauses:
Clause 1: A stent device, comprising: at least one radially expandable body portion extending along a longitudinal axis of the stent device defining a lumen; and at least one outwardly flarable portion connected to the body portion comprising at least one radially expandable ring connected to the body portion and at least one flaring connector connected to the at least one ring configured to cause a crown of the at least one ring to automatically flare radially outwardly relative to other portions of the ring upon radial expansion of the body portion so as to form a flared crown.
Clause 2: The stent device of clause 1, wherein the at least one flaring connector is not biased to the expanded position.
Clause 3: The stent device of clause 1, wherein the at least one flaring connector is biased to the expanded position.
Clause 4: The stent device of any of clauses 1-3, wherein the at least one ring comprises a plurality of substantially repeating bent segments and at least one longitudinally extending strut that connects at least one of the plurality of bent segments to the body portion of the stent device, and wherein each bent segment comprises a peak, a valley, and a transition region disposed between the peak and the valley.
Clause 5: The stent device of any of clauses 1-4, wherein, upon the radial expansion of the body portion, the flaring connector is configured to transition from a retracted position, in which the crown of the at least one ring is substantially longitudinally aligned with portions of the body portion of the stent device, to an expanded position, in which the flared crown of the at least one ring flares radially outwardly relative to other portions of the expandable body portion of the stent device.
Clause 6: The stent device of clause 5, wherein, when the flaring connector is in the retracted position, the crown of the at least one ring is equidistant from the longitudinal axis with the other portions of the at least one ring, and wherein, when the flaring connector is in the expanded position, the flared crown of the ring is located farther from the central longitudinal axis than the other portions of the at least one ring.
Clause 7: The stent device of any of clauses 1-6, wherein the outwardly flarable portion is positioned at an end of the stent device.
Clause 8: The stent device of any of clauses 1-7, wherein the radially expandable body portion comprises a first longitudinal section and a second longitudinal section, and wherein the outwardly flarable portion is disposed between the first longitudinal section and the second longitudinal section of the body portion.
Clause 9: The stent device of any of clauses 1-8, wherein the at least one radially expandable ring and the at least one flaring connector of the outwardly flarable portion comprises at least one first ring, at least one first flaring connector configured to flare a portion of the first ring, at least one second ring, and at least one second flaring connector configured to flare a portion of the second ring, and wherein the at least one first ring and the at least one second ring are arranged in series along the longitudinal axis of the stent.
Clause 10: The stent device of any of clauses 1-8, wherein the at least one radially expandable body portion comprises a plurality of radially expandable rings arranged in a series along the longitudinal axis of the stent device and at least one interconnecting member extending between and connecting the plurality of radially expandable rings, and wherein radially outward expansion of the plurality of radially expandable rings of the body portion causes the at least one flaring connector to cause the crown to automatically flare to form the flared crown.
Clause 11: The stent device of any of clauses 1-10, wherein the at least one radially expandable body portion comprises a plurality of radially expandable rings arranged in a series along the longitudinal axis of the stent device and at least one interconnecting member extending between and connecting the plurality of radially expandable rings, and wherein after radial outward expansion the at least one flaring connector inhibits the flared crown from collapsing.
Clause 12: The stent device of any of clauses 1-11, wherein the body portion, the outwardly flarable portion, or both portions are covered, at least in part, by at least one of a sheet, tube, or film formed from a material configured to reduce protein adsorption.
Clause 13: The stent device of clause 12, wherein the material configured to reduce protein adsorption comprises a PTFE membrane.
Clause 14: The stent device of any of clauses 1-13, wherein the at least one flaring connector comprises a first leg, a second leg, and a third leg fixedly connected together at a common point.
Clause 15: The stent device of clause 14, wherein the first leg comprises a first end opposite the common point, the second leg comprises a second end opposite the common point, and the third leg comprises a third end opposite the common point, and wherein, upon radially outward expansion of the expandable ring, a distance between the first end and the second end increases, and the third leg is rotated about the common point causing the crown of the at least one ring to automatically flare radially outwardly so as to form the flared crown.
Clause 16: The stent device of any of clauses 1-15, wherein the crown of the at least one ring comprises at least one barb configured to anchor the stent device at a deployed position when the flaring connector is in the expanded position.
Clause 17: The stent device of any of clauses 1-16, wherein the outwardly flarable portion is formed from a material without shape memory properties.
Clause 18: The stent device of any of clauses 1-16, wherein the outwardly flarable portion is formed from a material with shape memory properties.
Clause 19: The stent device of any of clauses 1-16, wherein the stent device is configured to expand radially outwardly in response to expansion of an expandable member positioned in the lumen defined by the body portion of the stent device.
Clause 20: The stent device of any of clauses 1-16, wherein the outwardly flarable portion is formed from one or more materials selected from the group consisting of stainless steel, cobalt chromium, nickel-titanium alloy, and biocompatible plastics.
Clause 21: The stent device of any of clauses 1-16, wherein the outwardly flarable portion comprises a shape-memory alloy that has been heat set to the expanded position such that the device is self-expanding.
Clause 22: The stent device of any of clauses 1-21, wherein the outwardly flarable portion is supported by a support strut that lessens an ability of a flare or a barb to be collapsed.
Clause 23: The stent device of any of clauses 1-13, wherein the at least one flaring connector comprises a first leg connected to the crown of the at least one ring and pairs of second legs extending from the first leg to other portions of the at least one ring, and wherein each pair of second legs connects to the first leg at unique common points on the first leg.
Clause 24: The stent device of any of clauses 1-13, wherein the at least one flaring connector comprises a first leg connected to the crown of the at least one ring and at least one pair of second legs extending from the first leg at a common point to portions of the at least one ring, and wherein at least one of the second legs comprises an expandable portion, which allows for further extension of the at least one second leg when the at least one flaring connector is in a nominally deployed configuration.
Clause 25: The stent device of any of clauses 1-13, wherein the outwardly flarable portion comprises: at least one first radially expandable ring connected to the body portion; at least one first flaring connector connected to the at least one first ring configured to cause a crown of the at least one first ring to automatically flare radially outwardly in a first direction relative to other portions of the first ring upon radial expansion of the body portion so as to form a first flared crown; at least one second radially expandable ring connected to the first at least one radially expandable ring; and at least one second flaring connector connected to the at least one second ring configured to cause a crown of the at least one second ring to automatically flare radially outwardly in a second direction different from the first direction and relative to other portions of the second ring, upon the radial expansion of the body portion so as to form a second flared crown.
Clause 26: The stent device of any of clauses 1-13, wherein, prior to the radial expansion of the body portion, an end of the stent device formed by portions of the crowns of the at least one ring is angled relative to a longitudinal axis of the at least one radially expandable body.
Clause 27: A method of deploying a stent device, comprising the steps of: preparing a stent device for a surgical procedure, the stent device comprising at least one radially expandable body portion extending along a longitudinal axis of the stent device defining a lumen; and at least one outwardly flarable portion connected to the body portion, the outwardly flarable portion comprising at least one radially expandable ring connected to the body portion and at least one flaring connector connected to the at least one ring configured to cause a crown of the at least one ring to automatically flare radially outwardly relative to other portions of the ring upon radial expansion of the body portion so as to form a flared crown; advancing the stent device, with the flaring connector in a retracted position, through a body lumen to a deployment location; and once in the deployment location, deploying the stent device, thereby allowing the body portion and at least one ring of the stent device to expand radially outwardly.
Clause 28: The method of clause 27, wherein advancing the stent device to the deployment location comprises advancing the stent device over a guidewire.
Clause 29: The method of clause 27 or clause 28, wherein the stent device is deployed by an endovascular technique or through a sidewall of the body lumen.
Clause 30: The method of any of clauses 27-29, wherein deploying the stent device further comprises expanding an expandable balloon positioned within the lumen of the stent device, thereby causing the body portion and the at least one expandable ring of the stent device to expand radially outwardly.
Clause 31: The method of any of clauses 27-29, wherein the stent device comprises a shape memory alloy and is internally biased to self-expand, and deploying the stent device further comprises releasing the internally biased stent device from a sheath, thereby causing the body portion and the at least one expandable ring of the internally biased stent device to expand radially outwardly.
Clause 32: The method of any of clauses 27-29, wherein the at least one flaring connector is not biased to an expanded position.
Clause 33: The method of any of clauses 27-29, wherein the at least one flaring connector is biased to an expanded position.
Clause 34: The method of any of clauses 27-29, wherein deploying the stent device comprises causing the crown of the at least one ring to automatically flare radially outwardly relative to the expandable body portion of the stent device without directly expanding the outwardly flarable portion by any expandable balloon.
Clause 35: The method of any of clauses 27-34, wherein the at least one flaring connector comprises a first leg connected to the crown of the at least one ring and pairs of second legs extending from the first leg to other portions of the at least one ring, and wherein each pair of second legs connects to the first leg at unique common points on the first leg.
Clause 36: The method of any of clauses 27-35, wherein the stent device is initially deployed to a nominally deployed configuration, the method further comprising, with the stent device in the nominally deployed configuration, advancing an expandable catheter to the stent device and expanding the expandable catheter within the lumen of the stent device for post-dilation of the stent device.
Clause 37: The method of clause 36, wherein the post-dilation of the stent device increases a diameter of the stent device by from 0.5 mm to 5 mm compared to a diameter of the stent device when the stent device is in the nominally deployed configuration.
Clause 38: The method of any of clauses 27-35, wherein the at least one flaring connector comprises a first leg connected to the crown of the at least one ring and at least one pair of second legs extending from the first leg at a common point to portions of the at least one ring, and wherein at least one of the second legs comprises an expandable portion, which allows for further extension of the at least one second leg when the at least one flaring connector is in a nominally deployed configuration.
Clause 39: The method of clause 38, wherein the stent device is initially deployed to the nominally deployed configuration, the method further comprising, with the stent device in the nominally deployed configuration, advancing an expandable catheter to the stent device and expanding the expandable catheter within the lumen of the stent device for post-dilation of the stent device, thereby causing the expandable portion of the second leg of the flaring connector to extend in length and a diameter of the stent device to increase.
Clause 40: The method of clause 39, wherein, during post-dilation of the stent device, the diameter of the stent device increases by from about 0.5 mm to about 5 mm from a diameter of the stent device in the nominally deployed configuration.
Clause 41: The method of any of clauses 27-40, wherein the outwardly flarable portion of the stent device comprises: at least one first radially expandable ring connected to the body portion; at least one first flaring connector connected to the at least one first ring configured to cause a crown of the at least one first ring to automatically flare radially outwardly in a first direction relative to other portions of the first ring upon radial expansion of the body portion so as to form a first flared crown; at least one second radially expandable ring connected to the first at least one radially expandable ring; and at least one second flaring connector connected to the at least one second ring configured to cause a crown of the at least one second ring to automatically flare radially outwardly in a second direction different from the first direction and relative to other portions of the second ring, upon the radial expansion of the body portion so as to form a second flared crown.
Clause 42: The method of clause 41, wherein the deployment location is selected such that, upon deployment of the stent device, an annular structure is retained within a groove defined by the first flared crowns and the second flared crowns for automatic alignment of the annular structure relative to the stent device at the deployment location.
Clause 43: The method of clause 42, wherein the annular structure retained within the groove comprises a fenestration ring of an endograft.
Clause 44: The method of any of clauses 27-43, wherein, prior to the radial expansion of the body portion of the stent device, an end of the stent device formed by portions of the crowns of the at least one ring is angled relative to a longitudinal axis of the at least one radially expandable body, and wherein the stent device is deployed adjacent to a branched vessel or artery.
Clause 45: The method of clause 44, wherein, when deployed, a shorter portion of the angled end of the stent device is positioned adjacent to an ostial opening in the branched vessel or artery and a longer portion of the angled end of the stent device is positioned on a sidewall of the vessel or artery opposite from the ostial opening.
Clause 46: A stent device comprising: at least one radially expandable body portion extending along a longitudinal axis of the stent device defining a lumen; and at least one outwardly flarable portion connected to the body portion comprising at least one radially expandable ring connected to the body portion and at least one flaring connector connected to the at least one ring configured to cause a crown of the at least one ring to automatically flare radially outwardly relative to other portions of the ring upon radial expansion of the body portion so as to form a flared crown, wherein the at least one flaring connector comprises a first leg connected to the crown of the at least one ring and pairs of second legs extending from the first leg to other portions of the at least one ring, and wherein each pair of second legs connects to the first leg at unique common points on the first leg.
Clause 47: The stent device of clause 46, wherein at least a portion of the flared crown is automatically bent radially inwardly and towards the body portion of the stent device.
Clause 48: The stent device of clause 46, wherein at least a portion of the flared crown is automatically bent radially inwardly and towards the body portion of the stent device at an angle of greater than 90° relative to a longitudinal axis of the stent device.
Clause 49: The stent device of any of clauses 46-48, wherein the flaring connector comprises two pairs of second legs and two common points.
Clause 50: The stent device of any of clauses 46-48, wherein the flaring connector comprises three or more pairs of second legs and three or more common points.
Clause 51: The stent device of any of clauses 46-50, wherein the second legs each comprise an end connected to the at least one ring, and wherein, upon radially outward expansion of the expandable ring, a distance between the ends of the second legs of each pair increases, causing portions of the first leg distal to each common point to rotate about the respective common point, thereby causing the crown of the at least one ring to automatically flare to form the flared crown.
Clause 52: The stent device of any of clauses 46-51, wherein, prior to radial expansion of the body portion, the first leg extends in an axial direction substantially parallel to a longitudinal axis of the stent body.
Clause 53: A stent device comprising: at least one radially expandable body portion extending along a longitudinal axis of the stent device defining a lumen; and at least one outwardly flarable portion connected to the body portion comprising at least one radially expandable ring connected to the body portion and at least one flaring connector connected to the at least one ring configured to cause a crown of the at least one ring to automatically flare radially outwardly relative to other portions of the ring upon radial expansion of the body portion so as to form a flared crown, wherein the at least one flaring connector comprises a first leg connected to the crown of the at least one ring and at least one pair of second legs extending from the first leg at a common point to portions of the at least one ring, and wherein at least one of the second legs comprises an expandable portion.
Clause 54: The stent device of clause 53, wherein the outwardly flarable portion is configured to adopt a nominally deployed configuration, in which an angle formed between the first leg and each second leg of the pair is less than about 120°, and wherein, in the nominally deployed configuration, the expandable portion of the at least one second leg is capable of further extension.
Clause 55: The stent device of clause 54, wherein the outwardly flarable portion is configured to transition from the nominally deployed configuration to a post-dilated configuration, and wherein the transition from the nominally deployed configuration to the post-dilated configuration causes extension of the expandable portion of the at least one second leg.
Clause 56: The stent device of any of clauses 53-55, wherein the expandable portion of the at least one second leg comprises at least one of a u-bend, a w-bend, an s-bend, and a j-bend.
Clause 57: The stent device of any of clauses 53-55, wherein the expandable portion comprises at least one curved segment of the at least one second leg having a curvature of greater than 90° and less than or equal to 180°.
Clause 58: The stent device of any of clauses 53-57, wherein the at least one flaring connector comprises at least two pairs of second legs extending from the first leg to other portions of the at least one ring, and wherein each pair of second legs connects to the first leg at unique common points on the first leg.
Clause 59: A stent device comprising: at least one radially expandable body portion extending along a longitudinal axis of the stent device defining a lumen; and at least one outwardly flarable portion connected to the body portion comprising: at least one first radially expandable ring connected to the body portion; at least one first flaring connector connected to the at least one first ring configured to cause a crown of the at least one first ring to automatically flare radially outwardly in a first direction relative to other portions of the first ring upon radial expansion of the body portion so as to form a first flared crown; at least one second radially expandable ring connected to the first at least one radially expandable ring; and at least one second flaring connector connected to the at least one second ring configured to cause a crown of the at least one second ring to automatically flare radially outwardly in a second direction different from the first direction and relative to other portions of the second ring, upon the radial expansion of the body portion so as to form a second flared crown.
Clause 60: The stent device of clause 59, wherein the first direction is towards a first end of the stent device and the second direction is towards the second end of the stent device.
Clause 61: The stent device of clause 59 or clause 60, wherein the first flared crown and the second flared crown extend radially outwardly and towards one another upon the radial expansion of the body portion.
Clause 62: The stent device of any of clauses 59-61, wherein the at least one outwardly flarable portion comprises a plurality of first flaring connectors connected to the at least one first ring and a plurality of second flaring connectors connected to the at least one second ring.
Clause 63: The stent device of clause 62, wherein each of the plurality of first flaring connectors is axially aligned with one of the plurality of second flaring connectors.
Clause 64: The stent device of clause 62 or clause 63, wherein each of the flaring connectors of the plurality of first flaring connectors and the plurality of second flaring connectors are equal in length.
Clause 65: The stent device of clause 62 or clause 63, wherein the plurality of first flaring connectors and the plurality of second flaring connectors each comprise at least one short flaring connector and at least one long flaring connector with an axial length longer than the short flaring connector.
Clause 66: The stent device of clause 65, wherein the plurality of first flaring connectors and the plurality of second flaring connectors each comprise multiple short flaring connectors and multiple long flaring connectors connected to the respective rings at alternating positions around the rings.
Clause 67: The stent device of clause 65 or clause 66, wherein a short flaring connector of the plurality of first flaring connectors is axially aligned with a long flaring connector of the plurality of second flaring connectors and/or wherein a long flaring connector of the plurality of first flaring connectors is axially aligned with a short flaring connector of the plurality of second flaring connectors.
Clause 68: The stent device of any of clauses 59-67, wherein the at least one first flaring connector and/or the at least one second flaring connector comprises a first leg connected to the crown of the at least one ring and at least one pair of second legs extending from the first leg to other portions of the at least one ring at a common point on the first leg.
Clause 69: The stent device of any of clauses 59-67, wherein the at least one first flaring connector and/or the at least one second flaring connector comprise a first leg connected to the crown of the at least one ring and pairs of second legs extending from the first leg to other portions of the at least one ring, and wherein each pair of second legs connects to the first leg at unique common points on the first leg.
Clause 70: A stent device comprising: at least one radially expandable body portion extending along a longitudinal axis of the stent device defining a lumen; and at least one outwardly flarable portion connected to the body portion comprising at least one radially expandable ring connected to the body portion and a plurality of flaring connectors connected to the at least one ring configured to cause crowns of the at least one ring to automatically flare radially outwardly relative to other portions of the ring upon radial expansion of the body portion so as to form flared crowns, wherein, prior to the radial expansion of the body portion, an end of the stent device formed by portions of the crowns of the at least one ring is angled relative to a longitudinal axis of the at least one radially expandable body.
Clause 71: The stent device of clause 70, wherein the end of the stent device formed by portions of the crowns, prior to the radial expansion of the body portion, is angled by from about 1 degrees to about 89 degrees relative to the longitudinal axis of the radially expandable body.
Clause 72: The stent device of clause 70 or clause 71, wherein the stent device is configured to be deployed in a branched vessel or artery, with a side of the stent device having a shorter axial length positioned near to a branched portion of the branched vessel, and a longer side of the stent device positioned against an opposite side of the vessel from the branched portion.
Clause 73: The stent device of any of clauses 70-72, wherein an end of the at least one radially expandable body portion of the stent device is angled relative to a longitudinal axis of the expandable body portion, thereby forming the angled end of the stent device.
Clause 74: The stent device of any of clauses 70-73, wherein axial lengths of the plurality of flaring connectors are different, thereby forming the angled end of the stent device.
Clause 75: The stent device of any of clauses 70-74, wherein one or more of the plurality of flaring connectors comprises a first leg connected to the crown of the at least one ring and pairs of second legs extending from the first leg to other portions of the at least one ring, and wherein each pair of second legs connects to the first leg at unique common points on the first leg.
These and other features and characteristics of the devices and other embodiments described herein, as well as the methods of operation and functions of the related elements of structures and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
The illustrations generally show preferred and non-limiting aspects of the devices, assemblies, and methods of the present disclosure. While the descriptions present various aspects of the devices and assemblies, it should not be interpreted in any way as limiting the disclosure. Furthermore, modifications, concepts, and applications of the disclosure's aspects are to be interpreted by those skilled in the art as being encompassed by, but not limited to, the illustrations and descriptions herein.
Further, for purposes of the description hereinafter, the terms “end”, “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal”, “radial”, and derivatives thereof shall relate to the disclosure as it is oriented in the drawing figures. The term “proximal” refers to the direction toward the center or central region of the device. The term “distal” refers to the outward direction extending away from the central region of the device. However, it is to be understood that the disclosure may assume various alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary aspects of the disclosure. Hence, specific dimensions and other physical characteristics related to the aspects disclosed herein are not to be considered as limiting. For the purpose of facilitating understanding of the disclosure, the accompanying drawings and description illustrate preferred aspects thereof, from which the disclosure, various aspects of its structures, construction and method of operation, and many advantages may be understood and appreciated.
The present disclosure is generally directed to a stent device, such as stent device 2 shown in
According to an aspect of the present disclosure, the stent device 2 can be an automatically flaring or self-flaring stent device including portions, such as an outwardly flarable portion 14, configured to flare radially outwardly relative to other portions of the stent device 2. As used herein, “automatically flaring” or “self-flaring” means that the outwardly flarable portion 14 of the stent device 2 moves to or adopts a flared configuration in response to radial expansion of other portions of the device 2, such as a body portion 12 of the device 2. The body portion 12 can be radially expanded using, for example, an expandable catheter, such as a dilating or balloon catheter. In response to radial expansion of the body portion 12, the outwardly flarable portion 14 moves to a flared position, in which the outwardly flarable portion 14 has a wider diameter and encloses a larger cross-sectional area than other portions of the expanded stent device 2.
The stent device 2 can, alternatively in accordance with another aspect of the present disclosure, be comprised of a shape-memory alloy that has been heat set such that the device is biased to the expanded position without the use of an expandable catheter, such as a dilating or balloon catheter. In this case, the body portion 12 can be radially expanded, for example, by removing a sheath that is used to restrain the device in a compressed manner. Once the sheath is removed, the stent device 2 automatically expands to a pre-set configuration. Expansion by a dilating or balloon catheter is not required. In response to radial expansion of the body portion 12, the outwardly flarable portion 14 moves to a flared position, in which the outwardly flarable portion 14 has a wider diameter and encloses a larger cross-sectional area than other portions of the expanded stent device 2. In this flared position, flared crowns of the stent device 2 are restrained from collapsing by support struts provided by flaring connectors 18. In this context of shape-memory alloy embodiments, the flaring connectors 18 serve as support struts when in the expanded position because shape-memory properties of such alloys (such as NITINOL) enable the flaring connectors 18 to support and maintain the expanded configuration of the stent device 2.
In some examples, the stent devices 2 disclosed herein are configured to expand in a non-uniform manner, meaning that the outwardly flarable portions 14 of the stent device 2 expands differently (e.g., expands to enclose a larger cross-sectional area or twists or rotates in a different manner) than other portions of the stent device 2. In conventional stent designs, non-uniform expansion is generally avoided. For example, non-uniform radial expansion typically is not desired in stent devices since stent devices are sized to fit within a single lumen diameter. Since non-uniform expansion is often avoided, any flaring is provided using a separate second balloon expansion performed after the conventional stent is deployed in the body lumen. For example, expansion using a separate second balloon is used in FEVAR procedures or in procedures in which an end of the stent conforms to an ostium (e.g., an entrance) of a body passageway or duct.
The stent device 2 having an automatically flaring or self-flaring design eliminates the need to introduce the second dilating or flaring catheter to flare portions of the implanted stent device radially outwardly, as is common practice for conventional stent designs. The non-uniform expansion of the stent device 2 also provides for enhanced migration resistance and fixation at select locations along the device length and/or in a prescribed direction. Also, it is believed that eliminating a need to introduce the second catheter into a body lumen to manipulate the stent device 2 reduces time of a stent deployment procedure, reduces costs of such procedures, reduces a probability of complications, reduces the need for radiation exposure during the deployment procedure, improves rates for technical and clinical success, and improves patient safety.
Further, it is understood that the arrangements of stent devices 2 disclosed herein are not limited to covered stents used as fenestrations in surgical procedures, such as fenestrated endovascular aneurysm repair (FEVAR). The stent device designs disclosed herein can be used in any number of medical applications and procedures, in which a self-flaring structure could be used for maintaining positioning of a medical device within a body lumen. For example, medical devices, including implantable grafts, fixation devices, drug delivery devices, filters, shunts, and similar medical devices, could all be modified to include the self-flaring designs of the present disclosure.
In some examples, the outwardly flarable portions 14 disclosed herein can also be adapted to deploy barbs, hooks, fasteners, pins, or anchors radially outwardly to contact and engage inner surfaces of a wall of the body lumens to enhance fixation between the implanted device and the wall. Such improved fixation could help to prevent implanted devices from migrating through the body lumen over time. Once the outwardly flarable portions 14 are deployed, the flaring connectors 18 used to help deploy the flarable crowns are put in tension, which inhibits the flared crowns from collapsing.
While it is not necessary for function of the stent device 2 disclosed herein that any portion of the device 2 is “self-expanding” or formed from a “self-expanding material,” in some examples, the body portion 12 or other portions of the stent device 2 may be self-expanding. As used herein, a portion of the stent device 2 is “self-expanding,” “biased to,” or “internally biased to” an orientation or position when internal forces of, for example, the body portion 12 of the stent device 2, cause the body portion 12 to adopt a particular orientation or position when deployed or in response to an activating condition, such as a change in temperature.
In some examples, stents formed from shape memory materials can be biased to a deployed or expanded state. Such biased stents are configured to automatically move from a retracted state to the deployed or expanded state immediately after the stent is pushed from a catheter and without, for example, needing to inflate a balloon or similar expandable structure to cause the stent to expand. In response to radial expansion of the body portion 12, the outwardly flarable portion 14 can “automatically” flare to the flared configuration as previously described. However, in such instances, the outwardly flarable portion 14 may not be formed from a self-expanding material or may not be biased to the flared configuration. Instead, the outwardly flarable portion 14 flares “automatically” in response to radial outward expansion of the body portion 12. In other words, in accordance with some embodiments of this disclosure, the stent device 2 is made of a self-expanding material, such as a heat-set, shape memory nickel-titanium alloy, so as to self-expand, thereby causing the flarable portion(s) 14 to automatically flare in conjunction with the self-expansion of the body portion(s) 12. In accordance with other embodiments of this disclosure, both the body portion(s) 12 and the flarable portion(s) 14 are made of a heat-set, shape memory nickel-titanium alloy so both the body portion(s) 12 and the flarable portion(s) 14 drive self-expansion.
As will be appreciated by those skilled in the art, manufacturing a stent device 2 to be biased to an expanded position can increase manufacturing costs, since shape memory materials can be more expensive than stent materials without shape memory properties. Manufacturing a stent to be biased to an expanded position also increases a complexity of the manufacturing process, which can further increase manufacturing costs. Accordingly, a stent device, such as the stent device 2 shown in
The stent device 2 does not have to be made out of a superelastic material, such as NITINOL (a nickel-titanium alloy distinguished from other materials by its shape memory and superelastic characteristics); however, the use of such materials can provide benefits that are useful for different applications. Thus, in accordance with some embodiments of this disclosure, the stent device 2 is made of a shape memory alloy. In accordance with other embodiments of this disclosure, the stent device 2 is made of materials other than shape memory alloy. The flaring connectors 18 and other portions of the device 2 disclosed herein can be “self-expanding” or “internally biased” to the expanded position as described herein. In this application, flared crowns 20b of the flarable portion 14 are supported by the flaring connector(s) 18 when the stent device 2 is in the expanded position. The flaring connector(s) 18 function as support struts when made from NITINOL and heat set in the expanded position. Thus, configurations of the stent device 2 disclosed herein may be made to be self-expanding or internally biased by making the device 2 out of NTINOL and heat setting the device 2 in an expanded condition to impart self-expanding, internally biased characteristics to the device 2. When configured in this manner, the flared crowns 20b are held in position by the flaring connector(s) 18 as long as the diameter of the device 10 remains in the expanded position, which produces the supported flares.
As used herein, a member or connector is “biased to” or “internally biased to” an orientation or position when internal forces of the member or connector cause the member or connector to adopt a particular orientation or position. For example, devices formed from shape memory materials can be biased to a deployed or expanded position, as described above, by heat setting. Such devices are configured to automatically move from a retracted position to the deployed or expanded position immediately after the device is pushed from a catheter and without, for example, needing to inflate a dilating or balloon catheter device to cause the device 10 to expand. Such devices are thus referred to as “self-expanding.” Some devices formed from shape memory materials can also adopt a new orientation or position in response to changes in temperature. For example, a device formed from a shape memory material can be configured to expand as temperature increases, as occurs when the device is implanted in the body. Accordingly, a device 2 that includes flared crowns 20b in the expanded position that are internally biased and supported from collapse with flaring connectors 18, as provided by the various stent devices 2 disclosed herein, offers certain benefits over currently available self-expanding devices.
With specific reference to
In some examples, the stent device 2 includes the radially expandable body portion 12 extending along a longitudinal axis L1 of the stent device 2 and the outwardly flarable portion 14 connected to or extending from the body portion 12. The outwardly flarable portion 14 includes a number of outwardly flarable or projecting structures, referred to herein as flarable crown portions or flarable crowns 20a, for maintaining positioning of the stent device 2 in the body lumen. The outwardly flarable portion 14 can allow for un-fettered access following deployment and allows the stent device 2 to conform to an ostium of a body passageway or duct. The flarable crowns 20a can include different types of rounded peaks, pointed peaks, protrusions, hooks, barbs, anchors, pins, or similar structures configured to flare radially outwardly upon radial expansion of the outwardly flarable portion 14. As described in detail herein, the arrangement, size, and shape of these projecting structures, crown portions, or flarable crowns 20a can be selected based on the intended application, deployment location of the stent device, and/or a size and shape of the stent device 2.
In some examples, as shown in
In some examples, the outwardly flarable portion 14 is connected to an end of the body portion 12, such that the outwardly flarable portion 14 forms the first end 4 of the stent device 2 as shown in
Stents with Flares at End(s)
An exemplary stent device 10 including a flarable end portion is shown in
In order to cause the flarable crowns 20a to flare radially outwardly, the flaring connector 18 is configured to transition between a retracted position (shown in
As discussed previously, the stent device 10 is automatically flaring or self-flaring. Therefore, unlike in conventional stent devices in which a second catheter is expanded to flare a particular region of the stent device 10 following deployment, the flaring connector(s) 18 of the present disclosure are configured to automatically transition from the retracted position to the expanded position in response to radial outward expansion of other portions or regions of the stent device 10, such as the body portion 12. As previously discussed, the flaring connector(s) 18 do not need to be self-expanding and/or internally biased to the expanded position to cause such transition, as occurs for a stent device 10 formed from a shape memory material.
In some examples, the at least one ring 16 of the outwardly flarable portion 14 is a circular or cylindrical structure, at least in the retracted position. When the flaring connector 18 is in the retracted position, the flarable crowns 20a of the ring 16 and the body portion 12 are each a same distance D1 (shown in
With specific reference to
In some examples, each bent segment 22 includes a peak 24, a valley 26, and a transition region 28 between the peak 24 and the valley 26. The segments 22 are arranged such that a transition region 28 of an adjacent bent segment 22 connects to a peak 24 or valley 26 of each bent segment 22. The ring 16 can also include the longitudinally extending struts 30 that connect some or all of the bent segments 22 to corresponding points on the body portion 12 of the stent device 10. For example, a strut 30 can extend between a valley 26 of a bent segment 22 of the ring 16 and a corresponding peak 34 of a ring 32 of the body portion 12.
With continued reference to
As was the case with the expandable ring 16 of the outwardly flarable portion 14, the rings 32 of the body portion 12 can include substantially repeating bent segments 38, which connect end-to-end about a circumference of the ring 32. Each bent segment 38 can include a peak 34, valley 40, and a transition region 42 extending between the peak 34 and the valley 40. The rings 32 can be arranged in a series along the longitudinal axis L1 of the stent device 10 in various orientations. For example, adjacent rings 32 can be aligned such that peaks 34 of one ring 32 are positioned near to valleys 40 of an immediately adjacent ring 32, as shown in
With continued reference to
The structure of the flaring connectors 18 and movement of the flaring connectors 18 between the retracted position and the expanded position will now be described in detail. As discussed previously, the flaring connectors 18 are configured to cause the flarable crowns 20a of the ring 16, such as shown in
In some examples, the flaring connector 18 is a framework, trestle, or connector including a sloped first portion or leg 52, a sloped second portion or leg 54, and a longitudinally extending third portion or leg 56. The legs 52, 54, 56 are fixedly connected together at a common point 58. In some embodiments, the common point 58 is a central point defining either a geometrical center or a center of mass for the flaring connector 18; however, in other embodiments the common point 58 is not a central point. As shown in
The portions or legs 52, 54, 56 of the flaring connector 18 are configured such that, upon radially outward expansion of the expandable ring 16, a distance between the first position 60 and the second position 62 increases as shown by comparing the distance D4 (in
In some examples, the legs 52, 54, 56 can be symmetrically-located with respect to the flarable crown 20a. However, this configuration of the legs 52, 54, 56 is not meant to limit the scope of the present disclosure, as embodiments can be determined by those skilled in the art in which one or more of the legs 52, 54, 56 are different lengths and/or are not symmetrical. For example, a length of one or more of the legs 52, 54, 56 can be adjusted or tuned to impart a degree of twist about an axis of the flarable crown 20a as it transitions to a flared crown 20b.
In some examples, the legs 52, 54 can be connected to circumferentially-periodic locations on the stent device 10, such as along the bent segments 22 or longitudinally extending struts 30 (shown in
As discussed previously, the outwardly flarable portion 14 of the stent device 10 is configured to assist in maintaining the deployed stent device 10 at a desired position within the body lumen as the result of the formation of flared crowns 20b from the flarable crowns 20a. The stent device 10 can also be configured to create an unfettered access to the stented vessel for future cannulation. In some examples, in order to anchor the stent device 10 at a desired deployment position, the ring 16 of the outwardly flarable portion 14 includes structures for engaging the wall of the body lumen to hold or anchor the stent device 10 in place. For example, as discussed herein, the flarable crowns 20a can include, for example, tines, barbs, or pins for engaging the wall of the body lumen. In some examples, such as when the stent device 10 is made of shape memory alloy, the outwardly flarable portion 14 forms flared crowns 20b after outward radial expansion and is inhibited from collapse by the flaring connectors 18, which also function as support struts in the expanded configuration.
The stent device 10 can be a covered or partially covered stent. An exemplary covered stent device 10 including features of the present disclosure is shown in a retracted state in
With reference to
With reference to
However, as shown in
As shown in
Further, while the bent segments 122 in
An exemplary stent device 210 including one or more flarable portions positioned between the ends of the stent device 210 is shown in
As in previous examples, the outwardly flarable portion 214 includes the expandable ring 216 including repeating bent segments 222 (shown in
The outwardly flarable portion 214 can also include struts 230 (shown in
In the example shown in
In some examples, the flarable crowns 220a and flared crowns 220b of the ring 216 can include protrusions 268, such as a barb, point, pin, or hook, which flare radially outwardly and press into the wall of the body lumen as the flaring connector 218 moves towards the expanded position and as the flarable crowns 220a flare to form flared crowns 220b. Like the flaring connector 218 and corresponding flarable crowns 220a, the protrusions 268 can be configured to remain in a retracted position while the stent device 210 is being advanced to the deployment position within the body lumen. Once the stent device 210 is in place in the body lumen, the protrusions 268 are configured to move along with the flaring connectors 218 and flared crowns 220b to adopt a deployed or outwardly projecting configuration and to engage the wall of the body lumen as a result of the formation of the flared crowns 220b.
Stents with Multiple Outwardly Flarable Rings
Exemplary stent devices 310, 410 including outwardly flarable portions 314, 414 having multiple rings 316a, 316b, 416a, 416b and rows of flaring connectors 318, 418 are shown in
As in previous examples, the body portion 312 includes the expandable ring(s) 332 connected by the interconnecting members 336. The body portion 312 is configured to expand radially outwardly when, for example, an expandable catheter, such as a balloon catheter, positioned in the body portion 312 is expanded by inflating the balloon, or, in the case of embodiments made of shape-memory alloy, when internal biasing forces provided by the shape-memory alloy cause automatic self-expansion to the expanded configuration. Expansion of the body portion 312 causes the outwardly flarable portion 314 to move from a retracted position to an expanded position, in which the flarable crowns 320a (shown in
The outwardly flarable portion 314 also includes the flaring connectors 318 connected to the rings 316a, 316b at various positions around a circumference of each ring 316a, 316b. For example, each ring 316a, 316b can include eight flaring connectors 318 spaced about the circumference of the rings 316a, 316b. In some examples, the flaring connectors 318 can be equidistantly spaced about the circumference of the rings 316a, 316b. In other examples, the flaring connectors 318 can be spaced apart by any distance. The flaring connectors 318 connected to the rings 316a, 316b can be substantially identical to each other and similar in structure to flaring connectors 18b shown in
Generally, an outwardly flarable portion 314 including multiple rings 316a, 316b provides for increased flaring motion or degree of flare compared with exemplary stent devices of this disclosure in which the outwardly flarable portion includes only a single ring. In particular, upon radial expansion of the body portion 312 of the stent device 310, the flarable crowns 320a of the second ring 316b flare radially outwardly, which effectively moves portions of the first ring 316a radially outwardly as well, so as to form a dual flare configuration. As the first ring 316a expands, the flarable crowns 320a of the first ring 316a also flare outwardly, resulting in an outwardly flarable portion 314 enclosing a larger cross-sectional area than if only a single ring were present.
Another exemplary stent device 410 including an outwardly flarable portion 414 including two rings 416a, 416b and two rows of flaring connectors 418 is shown in
Stents with Different Length Flaring Connectors
Another exemplary stent device 510 is shown in
As in previous examples, the outwardly flarable portion 514 includes the expandable ring 516 and flarable crowns 520a (shown in
The stent device 510 differs from previous examples in that the device 510 includes different sizes of flaring connectors 518a, 518b. For example, the outwardly flarable portion 514 can include a combination of long flaring connectors 518a and short flaring connectors 518b. The stent device 510 can include four long flaring connectors 518a and four short flaring connectors 518b. The flaring connectors 518a, 518b can be positioned in an alternating pattern about a circumference of the ring 516. In other examples, flaring connectors 518a, 518b can be arranged in any convenient pattern.
As shown in
In some examples, due to the varying degrees of height or amplitude, when deployed and expanded, the outwardly flarable portion 514 of the stent device 510 including flaring connectors 518a, 518b can have a partially folded appearance or fluted configuration in which some flared crowns 520b flare farther from the longitudinal axis L1 of the device 510 than other flared crowns 520b due to the difference in height and position of the flaring connectors 518a, 518b.
Stents with Curved Connectors
Another exemplary stent device 610 is shown in
The stent device 610 differs from previous examples in that the substantially straight longitudinally extending struts of previous examples are replaced with a flexible or curved connectors 630. The curved connectors 630 include a first end 660 connected to the valley 626 of the ring 616 of the outwardly flarable portion 614 and a second end 662 connected to a ring 632 of the body portion 612. For example, the second end 662 can be connected to a transition region 642 of the ring 632 near but slightly removed from the peak 634 of the ring 632 (i.e., offset from the peak 634 of the ring 632).
The curved connector 630 allows for greater freedom of movement of the outwardly flarable portion 614 relative to the body portion 612 as the stent device 610 expands and the flarable crowns 620a (shown in
Stents with Flaring Connectors Having Dual or Multiple Common Points
Additional exemplary stent devices 810 are shown in
The outwardly flarable portion 814 includes the expandable ring 816 and flarable crowns 820a (shown in
The stent devices 810 differ from previous examples in the configuration of the flaring connectors 818a, 818b. Unlike in previous examples, in which flaring connectors included one central or common point (such as the common point 58 shown in
In some examples, the flaring connectors 818a, 818b include an axially-oriented or first leg 852 connected to the flarable crown 820a of the ring 816. For example, the axially-oriented or first leg 852 may be connected at or adjacent to a peak 824 of the ring 816. The axially oriented or first leg 852 extends axially in a proximal direction from the peak 824 of the ring 816 towards the body portion 812 of the stent device 810. The flaring connectors 818a, 818b also include multiple pairs of side or second legs 854 extending from the first leg 852 to other portions of the ring 816. As used herein, a “pair of side or second legs” refers to two side or second legs 854 extending from the first leg 852 at the same common point, such as a first common point 858 (shown in
As shown in
As in previous examples, the flaring connectors 818a, 818b are configured to cause the flarable crowns 820a to flare radially outwardly relative to other portions of the ring 816 upon radial expansion of the body portion 812 to form the flared crowns 820b (shown in
As will be appreciated by those skilled in the art, the number of pairs of side or second legs 854 and common points 858, 860, 862 and distances D10, D12, D14 between the common points in the flaring connectors 818a, 818b, along with lengths of the side or second legs 854, affects the curvature and angle α10 of the flared connector 820b. Generally, including multiple pairs of second legs 854 and common points 858, 860, 862 allows for additional control over the curvature of the flared crown 820b. Additionally, the degree to which each pair of second legs 854 and common point 858, 860, 862 contributes to the overall flaring of the flared crown 820b is influenced by the distances D10, D12, D14 between the common points 858, 860, 862 and peak 824 as well as the length of second legs 854.
Flared crowns 20b, 820b including flaring connectors 18, 818a, 818b with different numbers of common points are shown in
In some examples, curvature of the flared crown 820b is selected and controlled for use in a specific surgical procedure, such as for use in fenestrated endovascular aneurysm repair (FEVAR) procedure. For FEVAR procedures, increasing flaring of the flared crown 820b may be important to better seal the fenestration. For example,
Stents with Flaring Connectors Adapted for Post-Dilation Repositioning
Another exemplary stent device 910 is shown in
The flaring connectors 918 include the axially-oriented or first leg 952 connected to the flarable crown 920a of the ring 916. For example, the first leg 952 can be connected at one end to the ring 916 near the peak 924 of the ring 916, and can extend axially in a proximal direction from the peak 924 of the ring 916 towards the body portion 912 of the stent device 910. The flaring connectors 918 also include one or more pairs of the side or second legs 954, which extend from the first leg 952 to portions of the ring 916. For example, as shown in
The flaring connectors 918 differ from previous examples because the second leg(s) 954 include expandable portions 964 that are capable of increasing in length following initial deployment of the stent device 910 to a nominally deployed configuration. As used herein, the “nominally deployed configuration” (shown in
In the “nominally deployed configuration”, the flaring connectors 918 may be arranged such that an angle α12 (shown in
In order to permit such post-dilation adjustment and repositioning, the expandable portion(s) 964 are desirably sufficiently rigid and/or are an appropriate geometry to resist extending and/or straightening during the initial deployment of the stent device 910 from the restrained position (shown in
The expandable portion 964 can refer to any portions or segments of the second leg(s) 954 that are capable of further extension when the outwardly flarable portion 914 is in the nominally deployed configuration (
In some examples, the expandable portion 964 can be a portion or segment of the side or second leg 954 including a stretchable or elastomeric material that permits substantial extension of the second leg 954. In other examples, the expandable portion 964 can include mechanical structures, such as springs, telescoping arrangements, and other mechanisms for extending a length of a member. With continued reference to
Stents with Opposing Flaring Connectors for Auto-Alignment
Another example of a stent device 1010 is shown in
The stent device 1010 differs from previous examples in that the outwardly flarable portion 1014 includes two expandable rings, such as the inner or first expandable ring 1016 and an outer or second expandable ring 1070. The first ring 1016 includes flarable crowns 1020a oriented in a first direction (e.g., pointing towards a first end of the stent device 1010) and the second ring 1070 includes flarable crowns 1074a oriented in a second direction (e.g., pointing towards a second end of the stent device 1010). Upon radial expansion of the body portion 1012 and rings 1016, 1070, the flarable crowns 1020a, 1074a are configured to flare radially outwardly and towards each other, as shown in
The first and second rings 1016, 1070 are arranged in series along the longitudinal axis L1 (shown in
The outwardly flarable portion 1014 also includes flaring connectors 1018 connected to the flarable crowns 1020a and flaring connectors 1072 connected to the flarable crowns 1074a. As in previous examples, the flaring connectors 1018, 1072 comprise a first leg 1052 and side or second legs 1054 connected together and to the first leg 1052 at a common point 1058. The flaring connectors 1018 are connected to the inner or first ring 1016 and are oriented in the first direction (e.g., pointing towards a first end of the stent device 1010). The flaring connectors 1072 are connected to the outer or second ring 1070 and are oriented in the opposite direction (e.g., pointing towards a second end of the stent device 1010). The flaring connectors 1018, 1072 are configured to cause the flarable crowns 1020a, 1074a to flare radially outwardly in response to radial expansion of the body portion 1012 and the rings 1016, 1070, which causes the flarable crowns 1020a, 1074a (shown in
A fenestration ring 1002 is often included in an endograft to allow for access to side branches. Since vessels leading into fenestrations may not be square (e.g. form 90° angles relative to each other) it is useful to have an auto-alignment feature on a self-flaring stent. Accordingly, the stent device 1010 includes the outwardly flarable portion 1014, which captures the fenestration ring 1002 and functions as an auto-alignment structure. In particular, the outwardly flarable portion 1014 of the stent device 1010 including the oppositely oriented rings 1016, 1070 can be configured to capture and align with the fenestration ring 1002 during deployment of the flarable crowns 1020a, 1074a to ensure that the stent device 1010 is properly aligned relative to the graft. By capturing and properly aligning with the fenestration ring 1002, the flared crowns 1020b, 1074b can ensure sufficient securement with the fenestration ring 1002, which desirably creates a seal sufficient to prevent leaks (e.g., type IIIa endoleaks).
With continued reference to
In some examples, the outwardly flarable portion 1014 includes flaring connectors 1018, 1072 of different lengths. For example, as shown in
In some examples, the short flaring connectors (shown by length L10) and the long flaring connectors (shown by length L12) can alternate around the circumference of each ring 1016, 1070, as shown in
The short and long flaring connectors 1018, 1072 may be provided to facilitate deployment of the stent device 1010 at a desired location relative to an endograft. Particularly, when implanting the stent device 1010 under fluoroscopy, it can be difficult to precisely align the stent device 1010 and fenestration ring 1002 of the endograft. Including the short and long flaring connectors 1018,1072 and flarable crowns 1020a, 1074a of varying lengths L10, L12 can facilitate such alignment by increasing a size of a target landing zone (i.e., a portion of the outwardly flarable portion 1014 which must contact the fenestration ring 1002 to successfully receive or capture the ring 1002) without substantially increasing a total length of the stent device 1010 or outwardly flarable portion 1014. Schematic drawings showing the stent device 1010 and fenestration ring 1002 are provided in
Stents with Angled Ends or Flares for Branched Vessels
Other exemplary stent devices 1110 are shown in
For stent devices 1110 with an angled end, a degree of flare of the flarable crowns 1120a can vary around the circumference of the stent device 1110, such that geometry of the flared crown 1120b is a function of circumferential position. It is believed that a stent device 1110 having an angled end with variable degrees of flare around the circumference of the device 1110 better accommodates a shape of an ostium at locations in the vasculature associated with bifurcations, as compared to previously described uniformly-flared stent devices (e.g., stent devices with flat ends). Areas of the vasculature associated with bifurcations include, for example, the common iliac/internal iliac artery bifurcation and upwardly-directed visceral vessels. When deployed in such bifurcations, a uniformly-flared stent device would protrude into the main vessel. In contrast, stent devices 1110 with the angled outwardly flarable portion 1114 better conform to shapes of ostial openings.
As in previous examples, the stent devices 1110 include the outwardly flarable portion 1114 connected to the body portion 1112 by longitudinal struts 1130 of the expandable ring 1116. For example, the struts 1130 can extend between a valley 1126 of the ring 1116 of the outwardly flarable portion 1114 and a peak 1134 of a ring 1132 of the body portion 1112, or between any other convenient positions on the rings 1116, 1132. The outwardly flarable portion 1114 includes the expandable ring 1116 and flarable crowns 1120a which, upon radially outward expansion of the body portion 1112 of the stent device 1110, flare radially outwardly to form flared crowns 1120b (shown in
The stent devices 1110 can include a variety of structural features and configurations for providing the angled end of the outwardly flarable portion 1114. In some examples, as shown in
In other examples, as shown in
With reference to
At step 712 of the method, a delivery assembly including a catheter or sheath and a guidewire for advancing the stent device through vasculature of a patient to a deployment location are provided. The deployment location can be any desired position within the vasculature of the patient. For example, the stent device can be deployed in a vessel or artery. In some examples, the stent device is deployed within an endograft. For stent devices having an outwardly flarable portion with an angled end, as shown in
At step 718 of the method, once the stent device is at the desired deployment location, the balloon catheter is expanded. Radial outward expansion of the expandable portion of the balloon catheter causes the expandable rings and outwardly flarable portions of the stent device to expand outwardly, as described previously. In the case of self-expanding stent devices, such as stent devices made of shape-memory alloy, the step 718 may be modified to merely release the stent device from the delivery system in order to allow the self-expanding stent device to self-expand to an internally biased configuration previously created by heat setting. In this case, releasing the self-expanding stent device involves releasing the stent device from the delivery system so that the self-expanding stent device is no longer constrained by the stent delivery system to remain in the retracted configuration. As a consequence of its release from the stent delivery system, the self-expanding stent device is free to self-expand into the expanded position without the need to expand a balloon.
At step 720 of the method, in response to expansion of the rings, the flaring connectors transition from the retracted position to the expanded position causing portions of the expandable ring of the outwardly flarable portion to flare. For example, upon expansion of the body portion and ring, the first and second portions or legs of each flaring connector can move away from one another, thereby causing the third portion or leg of the flaring connector to rotate forward in the direction of arrow A2 (as shown in
With continued reference to
The following examples are presented to demonstrate the general principles of embodiments of this disclosure. This disclosure, and any claimed embodiments, should not be considered as limited to the specific examples presented.
An auto-flaring or self-flaring stent design was modeled using commercially available computer aided design (CAD) and computer aided engineering (CAE) software. Specifically, SolidWorks 2016 was used for CAD model creation of the stent design. Abaqus/CAE 2016 was used for finite element model pre- and post-processing. Abaqus/Standard 2016 was used as a finite element solver. The modeled design included flared sections of the stent configured to be controlled by expansion of the diameter of the stent. For illustration purposes, only the last three ring elements of the stent are shown in
The model stent was then virtually expanded to an internal diameter of 8 mm to visualize behavior of the flaring feature. As the internal diameter was increased, the flare also increased in diameter as seen in
Prototypes were then fabricated out of stainless steel according to the model stent design. One of the prototype stent samples was loosely placed on an 8 mm diameter balloon catheter. The balloon was expanded to 8 ATM, and then to 10 ATM. The balloon was then deflated and the prototype stent was removed. Photographs of the expanded prototype stent are shown in
A comparison was then made between the predictive computer-generated model of the stent and the prototype stent after expansion to 8 mm. End views of the model and prototype are shown in
Four prototypes of the auto-flaring stent, as described in Example 1 and as depicted in
Visual inspection concluded that all of the flared end struts remained fully encapsulated in the ePTFE covering. The standard inner diameter ID (shown in
The inventors conclude that the measured degree of flare in these examples demonstrates that a significant flare can be imparted on an ePTFE covered stent through stent design and expansion diameter using a standard straight balloon catheter.
A model 1200 was created of an endovascular abdominal aortic aneurysm (AAA device 1210) device with fenestrations 1212, 1214. A schematic representation of the AAA model 1200 is shown in
In Position B, the flared portion 1222 of the covered stent 1218 is positioned through the fenestration 1214 and adjacent to a wall of the AAA device 1210. While not intending to be bound by theory, it is believed that the flares or flared portions 1220, 1222 serve multiple purposes including maintaining stent positioning in the AAA device 1210, preventing endoleaks, and facilitating placement of a guidewire for future procedures that may be necessary.
Although embodiments of this disclosure have been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred aspects, it is to be understood that such detail is solely for that purpose and that Applicant's invention is not limited to the disclosed aspects, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present disclosure contemplates that, to the extent possible, one or more features of any aspect can be combined with one or more features of any other aspect.
This application claims priority to U.S. Provisional Patent Application No. 62/866,414, filed Jun. 25, 2019, and U.S. Provisional Patent Application No. 62/965,373, filed Jan. 24, 2020, the disclosures of which are hereby incorporated by reference in their entireties.
Number | Date | Country | |
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62866414 | Jun 2019 | US | |
62965373 | Jan 2020 | US |