Patent Application
20160022291
Embodiments of the invention relate generally to devices and methods for retrieving or manipulating objects within a lumen. More specifically, embodiments of the invention relate to devices and methods for retrieving or manipulating medical devices from a body lumen.
Embolic protection is utilized throughout the vasculature to prevent the potentially fatal passage of embolic material in the bloodstream to smaller vessels where it can obstruct blood flow. The dislodgement of embolic material is often associated with procedures which open blood vessels to restore natural blood flow such as stenting, angioplasty, arthrectomy, endarterectomy or thrombectomy. Used as an adjunct to these procedures, embolic protection devices trap debris and provide a means for removal for the body.
One widely used embolic protection application is the placement of filtration means in the vena cava. Vena cava filters (VCF) prevent the passage of thrombus from the deep veins of the legs into the blood stream and ultimately to the lungs. This condition is known as deep vein thrombosis (DVT), which can cause a potentially fatal condition known as pulmonary embolism (PE).
The next advancement in filters added the element of recoverability. Retrievable filters were designed to allow removal from the patient subsequent to initial placement. These filters can incorporate retrieval features that can be grasped and/or secured by a retrieval device, such as a snare based retrieval device. Grasping the retrieval feature using a snare generally requires the user to manipulate the snare over the retrieval feature, which can be difficult due to a variety of factors, such as retrieval feature geometry and location within the lumen, the structure and properties of the snare, and ability to visualize the retrieval feature and/or snare using a real-time visualization technique such as fluoroscopy.
Accordingly, it would be desirable to have an improved retrieval device that would facilitate engagement with a retrieval feature on a device making retrieval and/or manipulation of the device easier and faster to complete.
The present invention relates generally to devices and methods for retrieving or manipulating objects within a lumen. More specifically, embodiments of the invention relate to devices and methods for retrieving or manipulating medical devices from a body lumen.
One embodiment of the present invention provides a novel and improved retrieval snare and method of fabricating and using the same. The snare includes a snare wire, having a distal end and a proximal end, for use in the human anatomy, such as but not limited to blood vessels, pulmonary airways, reproductive anatomy, gastrointestinal anatomy, and organs such as the bladder, kidneys or lungs. The device enables a user to capture a foreign object located within the human anatomy, grasp said object in a controlled manner, and retrieve and remove said object from the human anatomy. Examples of foreign objects which might be removed from the human anatomy include implants such as stents, guidewires, leads, sheaths, filters, and valves, and organic objects such as kidney stones or calcified emboli. Other areas where embodiments of the snare can be used include, for example, removal and/or repositioning of distal protection devices that are used in a variety of medical procedures such as carotid stenting and percutaneous aortic valve replacement; and abdominal aortic aneurysm and thoracic aortic aneurysm devices. For example, a snare can be used to capture a vena cava filter and pull it into a retrieval sheath for removal from the patient. The snare is advanced through one or more retrieval sheaths, up to the site of a deployed filter. The snare is then deployed into the vessel, and engaged with the filter. Finally, the snare is held under tension while the sheath is advanced over said filter, collapsing it into the ID of said sheath. Another example is the use of a snare to grasp and extract loose kidney stones from a patient's kidneys. The snare is advanced through one or more sheaths, up to the site of the loose kidney stone. The snare is then deployed and engaged with the stone. Next, the snare is pulled into the sheath, drawing the stone into the distal ID of said sheath.
In some embodiments, a device for retrieving an object from a lumen is provided. The device includes a sheath configured to fit within the lumen, the sheath having a proximal end and a distal end. A snare can be disposed within the sheath. The snare can have a shaft with a longitudinal axis, a proximal end and a distal end and a plurality of loop elements in connection with the distal end of the shaft. The plurality of loop elements can have a collapsed configuration within the sheath and at least one deployed configuration outside the sheath. The plurality of loop elements can be configured to be deployed through an opening at the distal end of the sheath. The at least one deployed configuration can include a fully deployed configuration in which the plurality of loop elements are deployed in a propeller-like configuration.
In some embodiments, the first sheath includes a flexible distal tip portion that is configured to invert when the object is withdrawn into the sheath.
In some embodiments, a plurality of sheaths includes flexible distal tip portions that are configured to invert when the object is withdrawn into the sheaths.
In some embodiments, the plurality of loop elements in the fully deployed configuration are angled less than 90 degrees with respect to the longitudinal axis of the shaft such that the plurality of loop elements has an axial reach both proximal and distal the distal end of the shaft.
In some embodiments, each of the plurality of loop elements includes at least one shape memory wire and one radiopaque wire.
In some embodiments, the shape memory wire is made of a nickel titanium alloy and the radiopaque wire is made of platinum.
In some embodiments, the loop elements in the fully deployed configuration are arranged to form a circle geometry when viewed along the longitudinal axis.
In some embodiments, the object being retrieved by the device is a filter having a retrieval element and a support member, and wherein the axial reach of the loop elements in the fully deployed configuration is less than the distance between the retrieval element and the support member.
In some embodiments, the proximal portion of the sheath and the proximal portion of the shaft are connected with a snap fitting.
In some embodiments, the proximal portion of the outer sheath and the proximal portion of the inner sheath are connected with a snap fitting.
In some embodiments, the device further includes an outer sheath, wherein the sheath is disposed within the outer sheath.
In some embodiments, the outer sheath has greater column strength than the inner sheath.
In some embodiments, the loop elements have a plurality of deployment configurations, and wherein the proximal portion of the shaft includes a plurality of indicators that correspond to the plurality of deployment configurations.
In some embodiments, the plurality of indicators includes a plurality of detents.
In some embodiments, the proximal portion of the sheath includes a first tactile identifier and the proximal portion of the shaft includes a second tactile identifier, wherein the first tactile identifier is different from the second tactile identifier.
In some embodiments, the at least one deployed configuration includes an initial deployed configuration in which the plurality of loop elements are deployed substantially transversely with respect to the longitudinal axis.
In some embodiments, the plurality of loop elements is deployed in a clover leaf configuration in the initial deployed configuration.
In some embodiments, the at least one deployed configuration includes an intermediate deployed configuration in which the plurality of loop elements are deployed substantially axially with respect to the longitudinal axis.
In some embodiments, a method for capturing an object in a lumen defined by a lumen wall is provided. The method includes advancing a sheath within the lumen, the sheath having a proximal end and a distal end, until the distal end of the sheath is proximal the object; deploying a plurality of loop elements of a snare out of the distal end of the sheath in a propeller-like configuration; and capturing a portion of the object with at least one of the plurality of loop elements.
In some embodiments, the method further includes withdrawing the loop elements in a proximal direction to engage the portion of the object.
In some embodiments, the method further includes rotating the loop elements to engage the portion of the object.
In some embodiments, the method further includes retracting the portion of the object within the sheath.
In some embodiments, the method further includes advancing an outer sheath over the object.
In some embodiments, the method further includes advancing the snare to a full deployment detent on the snare.
In some embodiments, the method further includes visualizing the snare in the lumen using fluoroscopy.
In some embodiments, the method further includes decoupling a snap fitting holding together the sheath and the snare.
In some embodiments, the method further includes decoupling a snap fitting holding together the outer sheath and the inner sheath.
In some embodiments, a device for retrieving an object from a lumen is provided. The device can include a sheath configured to fit within the lumen, the sheath having a proximal end, a distal end and a radiopaque marker offset from the distal end. A snare can be disposed within the sheath, the snare having a shaft with a longitudinal axis, a proximal end and a distal end and a plurality of loop elements in connection with the distal end of the shaft. The plurality of loop elements can have a collapsed configuration within the sheath and at least one deployed configuration outside the sheath. The plurality of loop elements can be configured to be deployed through an opening at the distal end of the sheath. At least one deployed configuration can include an initial deployed configuration in which the plurality of loop elements is deployed substantially transversely with respect to the longitudinal axis.
In some embodiments, the plurality of loop elements are deployed in a clover leaf configuration in the initial deployed configuration.
In some embodiments, the plurality of loop elements are deployed in an elliptical or oblong configuration in the fully deployed configuration.
In some embodiments, the at least one deployed configuration includes a fully deployed configuration in which the plurality of loop elements are deployed in substantially circular configuration.
In some embodiments, the radiopaque marker is offset about 3 to 5 mm from the distal end of the sheath.
In some embodiments, a specific radiopaque marker pattern is disposed on each of the loop elements to enable visual differentiation of each loop element fluoroscopically. For example, each loop element can have a different number of radiopaque markers.
In some embodiments, a method for capturing an object in a lumen defined by a lumen wall is provided. The method includes advancing a sheath within the lumen, the sheath having a proximal end and a distal end, until the distal end of the sheath is proximal the object; deploying a plurality of loop elements of a snare out of the distal end of the sheath until the loop elements achieve substantially full apposition with the circumference of the lumen wall; and capturing a portion of the object with at least one of the plurality of loop elements.
In some embodiments, the method further includes aligning a radiopaque marker offset from the distal end of the sheath with a radiopaque feature of the object.
In some embodiments, the radiopaque feature of the object is a retrieval element.
In some embodiments, a device for retrieving an object from a lumen defined by a lumen wall is provided. The device can include a sheath configured to fit within the lumen, the sheath having a proximal end and a distal end; and a snare slidably disposed within the sheath, the snare having a shaft with a longitudinal axis, a proximal end and a distal end and a plurality of loop elements in connection with the distal end of the shaft, wherein each of the plurality of loop element has a proximal portion and a distal portion, wherein the plurality of loop elements has a collapsed configuration within the sheath and at least one deployed configuration outside the sheath, wherein the plurality of loop elements are configured to be deployed through an opening at the distal end of the sheath, wherein the at least one deployed configuration includes a fully deployed configuration in which the plurality of loop elements are deployed such that the distal portions of the loop elements are arranged in a substantially continuous, circumferential, planar and oblong configuration that is transverse to the longitudinal axis.
In some embodiments, the sheath includes a flexible distal tip portion that is configured to invert when the object is withdrawn into the sheath.
In some embodiments, the plurality of loop elements in the fully deployed configuration are angled less than 90 degrees with respect to the longitudinal axis of the shaft such that the plurality of loop elements has an axial reach both proximal and distal the distal end of the shaft.
In some embodiments, each of the plurality of loop elements includes at least one shape memory wire and one radiopaque wire. In some embodiments, the shape memory wire is made of a nickel titanium alloy and the radiopaque wire is made of platinum.
In some embodiments, the proximal portions of the plurality of loop elements comprise spoke portions that are secured together with a flexible sleeve.
In some embodiments, the object is a filter having a retrieval element and a support member, and wherein the axial reach of the loop elements in the fully deployed configuration is less than the distance between the retrieval element and the support member.
In some embodiments, the proximal portion of the sheath and the proximal portion of the shaft are connected with a snap fitting.
In some embodiments, the device further includes an outer sheath, wherein the sheath is disposed within the outer sheath.
In some embodiments, the outer sheath has greater column strength than the sheath.
In some embodiments, the loop elements have a plurality of deployment configurations, and wherein the proximal portion of the shaft includes a plurality of indicators that correspond to the plurality of deployment configurations. In some embodiments, the plurality of indicators comprise a plurality of detents. In some embodiments, the proximal portion of the sheath includes a first tactile identifier and the proximal portion of the shaft includes a second tactile identifier, wherein the first tactile identifier is different from the second tactile identifier.
In some embodiments, the at least one deployed configuration includes an initial deployed configuration in which the plurality of loop elements are deployed substantially axially with respect to the longitudinal axis.
In some embodiments, the distal portions of the plurality of loop elements in the fully deployed configuration are configured to achieve complete circumferential apposition with the lumen wall. In some embodiments, the lumen wall can define a lumen that is oblong or circular or that changes between oblong and circular.
In some embodiments, the at least one deployed configuration includes an intermediate deployed configuration in which the plurality of loop elements are deployed substantially transversely with respect to the longitudinal axis.
In some embodiments, a device for retrieving an object from a lumen is provided. The device can include a sheath configured to fit within the lumen, the sheath having a proximal end, a distal end and a radiopaque marker offset from the distal end; and a snare disposed within the sheath, the snare having a shaft with a longitudinal axis, a proximal end and a distal end and a plurality of loop elements in connection with the distal end of the shaft, wherein the plurality of loop elements has a collapsed configuration within the sheath and at least one deployed configuration outside the sheath, wherein the plurality of loop elements are configured to be deployed through an opening at the distal end of the sheath, wherein the at least one deployed configuration includes an initial deployed configuration in which the plurality of loop elements are deployed substantially transversely with respect to the longitudinal axis.
In some embodiments, the at least one deployed configuration includes a fully deployed configuration in which the plurality of loop elements are deployed in substantially circular configuration.
In some embodiments, the radiopaque marker is offset about 3 to 5 mm from the distal end of the sheath.
In some embodiments, the at least one deployed configuration includes a fully deployed configuration in which the plurality of loop elements are deployed in substantially oblong configuration.
In some embodiments, the plurality of loop elements each includes a loop collapse facilitator.
In some embodiments, the plurality of loop elements are secured together with sleeves.
In some embodiments, a method for capturing an object in a lumen defined by a lumen wall is provided. The method can include advancing a sheath within the lumen, the sheath having a proximal end and a distal end, until the distal end of the sheath is proximal the object; deploying a plurality of loop elements of a snare out of the distal end of the sheath until the loop elements achieve substantially full apposition with the circumference of the lumen wall; and capturing a portion of the object proximate to the lumen wall with at least one of the plurality of loop elements.
In some embodiments, the method further includes aligning a radiopaque marker offset from the distal end of the sheath with a radiopaque feature of the object.
In some embodiments, the radiopaque feature of the object is a retrieval element.
In some embodiments, the method further includes advancing the distal end of the sheath over the captured object.
In some embodiments, the distal end of the sheath inverts as the sheath is advanced over the captured object.
In some embodiments, a method for capturing an object in a lumen defined by a lumen wall is provided. The method includes advancing a sheath within the lumen, the sheath having a proximal end and a distal end, until the distal end of the sheath is proximal the object; determining the position of the object within the lumen; deploying a plurality of loop elements of a snare out of the distal end of the sheath to one of a plurality of predetermined loop element deployment configurations based on the determination of the position of the object; and capturing a portion of the object with at least one of the plurality of loop elements.
In some embodiments, the plurality of loop elements are deployed to the predetermined loop element deployment configuration using a deployment indicator.
In some embodiments, the method further includes advancing an inner sheath disposed with the sheath over a portion of the object and advancing the sheath over the entire object.
The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
As illustrated in
The loop elements 18 can have a region of overlap 31, with a span L1, between the adjacent loop elements. In some embodiments, L1 can be less than about 5, 10, 15, 20, 25, 30, 35, 40 or 45 degrees. In some embodiments, L1 can be between about 0 to 45 degrees, or about 0 to 15 degrees. The span of radial or circumferential coverage by each loop element 18 can be defined by the angle α between the two spoke elements 30 of the loop element 18, as shown in
The shape and flexibility of the loop elements 18 allows them to collapse and/or fold down easily into, for example, a 7 Fr or smaller sheath catheter 22 during loading of the device 10 into the sheath 22 and/or during deployment of the device 10 from the sheath 22 and retraction of the device 10 into the sheath 22, as illustrated in
In some embodiments, as illustrated in
In some embodiments, the distal tip portion 32 of the sheath 22 can be radiopaque and/or include a radiopaque marker. For example, in some embodiments, the polymer forming the distal tip portion 32 can be doped with radiopaque elements or compounds, such as barium, tantalum, tungsten, palladium, platinum or iridium based compounds or elements. Alternatively or in addition to the radiopaque doping, a single or plurality of radiopaque markers, such as a radiopaque marker band made of the radiopaque elements or compounds described herein, can be incorporated into the distal tip portion 32. In some embodiments, the radiopaque marker band can be offset approximately 1-10 mm, or about 3-mm from the distal end of the sheath 22, so as to not interfere with the elasticity and eversion of the distal tip portion 32 during the capture process. The radiopaque doping and/or marker allow the operator to visualize the location of the distal tip portion 32 of the sheath 22 during insertion, advancement, and positioning of the sheath 22 near the foreign object within the lumen. This allows the operator to accurately and precisely advance and position the tip of sheath 22 to the foreign object. In some embodiments where an outer sheath is combined with the retrieval sheath, each sheath can employ different radiopaque marker patterns to allow the operator to differentiate between the two sheaths fluoroscopically.
In addition, the marker offset can also function as an alignment feature which aids the operator in positioning the distal end of the sheath 22 in the proper location relative to the foreign object to be retrieved. For example, the foreign object can be a filter 40 with a frame 52, a plurality of anchors 50 on the frame 40 and a retrieval element 42 as illustrated in
In some embodiments, the shaft 12 is straight and can be made of polymeric or metallic material, for example. The shaft 12 can be made of a solid design such as a wire, but can alternatively be hollow to facilitate passage of secondary devices through a lumen in the shaft 12. The shaft 12 can be of a single wire or element, but can also be constructed of a plurality of wires or elements which can be braided, twisted or stranded into a single shaft 12. The shaft 12 provides a means by which the user can advance, manipulate, and retract the distal end 14 of the device to capture and remove a foreign object from the human body. Typically, the user manipulates the device 10 at the proximal end 16, which is typically outside of the human anatomy. By manipulating the shaft 12, the motion is translated to the distal end 14 of the device 10, which in turn causes the loop elements 18 to move within the human anatomy. This motion allows the loop elements 18 to catch on the foreign object to be removed from the body. Consequently, the shaft 12 can be designed to have sufficient stiffness, flexibility, pushability and torqueability to accomplish the functions described herein. In some embodiments, a single wire shaft can provide sufficient stiffness, flexibility, pushability and torqueability. In other embodiments, a multiple wire shaft can provide sufficient stiffness, flexibility, pushability and torqueability.
In some embodiments, a hypo tube 20 attaches the loop elements 18 to the shaft 12. The hypo tube 20 has an inner diameter and an outer diameter, and is typically sized such that the shaft 12 and all of the loop elements 18 can fit within the inner diameter of the hypo tube 20. The inner diameter is sized such that there is adequate interference between the hypo tube 20 and the shaft 12 and the loop elements 18, so that the hypo tube 20 can be swaged or crimped circumferentially, mechanically locking the loop elements 18 and shaft 12 together. Additionally, the hypo tube can be radially shaped into a non-circular shape, such as but not limited to a hexagon or square or other rectilinear shape, to further facilitate mechanical fit and locking of said shaft 12 and loop elements 18. In some embodiments, the length of the hypo tube 20 is about at least two times its outer diameter, but can be as short as one times its outer diameter, or as long as twenty times its outer diameter. The loop elements 18 can also be attached to the shaft 12 via welding, soldering, capturing within a coil, or potting within a polymeric or rigid adhesive form, for example.
In some embodiments, the loop elements 18 have a geometric shape which allows them to deploy in a staged manner, where the shape and effective diameter of the snare 10 is dependent upon how far the snare 10 is deployed out of the sheath 22. In a first deployment stage as shown in
To facilitate engagement of the loop elements 18 with the retrieval element, the loop elements 18, when fully deployed, can be sized to conform approximately to the inner diameter of the lumen in which the foreign object is located. This allows full or substantially full apposition between the loop elements 18 and the full circumference of the lumen wall, which enhances the ability of the snare 10 to capture the retrieving element. In some embodiments, the geometry of the fully deployed loop elements 18 can be substantially elliptical, oval or oblong in order to conform to a lumen with a substantially elliptical, oval or oblong cross-sectional geometry. In these embodiments, the major axis of the elliptical or oblong geometry can be sized to conform approximately to the inner diameter of the lumen in which the foreign object is located. In general terms, the geometry of the fully deployed loop elements 18 can substantially match the geometry of the lumen.
For example, the vena cava may have a generally elliptical or oblong cross-sectional geometry. For use in the vena cava, a snare 10 with loop elements 18 having a substantially elliptical or oblong fully deployed configuration can be used advantageously, as shown in
In some embodiments, each individual loop element 18 can employ a single or plurality of radiopaque markers 56, such that each loop element 18 has a different quantity of radiopaque markers 56, or a different pattern of radiopaque markers 56, to allow the operator to visually differentiate and identify each loop element 18 fluoroscopically, as shown in
In some embodiments, the loop elements 18 can be attached or connected together using a variety of techniques, as illustrated in
In some embodiments, the loop elements 18 can include a single or plurality of loop collapse facilitator 23 features, as shown in
In addition, the loop collapse facilitator 23 can be oriented in a variety ways. For example, the loop collapse facilitators 23 can be pointed or extend either in a distal direction, as shown in
The diameters of the wires can be 0.002″-0.007″ each. The wires can be tightly wound together, and then formed into a loop element 18 of the desired shape. The loop element 18 outer radiused edge portion 26 can be angled such that the span of the radiused edge portion 26 is at angle of between about 45 degrees and 90 degrees, relative to the axis of the shaft 12.
The loop element 18 of one embodiment, as illustrated in
In contrast, in some embodiments a snare 10 with fewer loop elements 18, such as two loop elements 18, can be more easily visualized using real time imaging techniques, thereby allowing the operator to accurately identify each loop element 18 and therefore efficiently manipulate the position and orientation of the snare with respect to the foreign object. The two loop element embodiment, as discussed above, can still be capable of achieving complete or substantial circumferential apposition with the lumen wall. In some embodiments with too few loop elements 18, such as a single loop element, the single loop element can be too floppy, and a floppy loop element 18 can be difficult to precisely manipulate and position, making grasping a small retrieval element on a foreign object more difficult.
The loop elements 18 have a geometry that enables them to catch easily on foreign objects in the human anatomy. In some embodiments as shown in
In some embodiments, the two straight spoke portions 30, which radiate from the central axis of the hypo tube to the outer radius of the radiused edge portion 26, are set at an angle α of about 90 degrees, for a snare 10 with four loop elements 18. In some embodiments, the angle α between the two straight spoke portions 30 can be less than 90 degrees when, for example, the snare 10 has more than four loop elements 18, such as an angle of about 60 degrees for a snare 10 with six loop elements 18, or an angle of about 72 degrees for a snare 10 with 5 loop elements. To generalize, in some embodiments, the angle in degrees between the straight spoke portions 30 can be determined by dividing 360 by the number of loop elements 18 in the snare 10. This results in a configuration where the loop elements 18 cover an entire circle of space when viewed along the axial axis. Therefore, in an embodiment of the snare 10 with three loop elements 18, the angle between the two straight spoke 30 portions can be about 120 degrees. In some embodiments, the angle α between the straight spoke portions 30 can be greater than as determined using the formula set forth above, which results in an overlap of portions of the loop elements 18 with adjacent loop elements 18. In some embodiments, the angle between the two straight spoke 30 portions is greater than the value calculated in the formula set forth above, where an angle of about 5 to 15 degrees ensures that there is minimal or no gap about the perimeter of the snare, to form a closed circle.
In some embodiments, from a transverse view, the large radiused edge portion 26 of the loop element 18 can be angled between about 90 degrees and about 30 degrees relative to the axis of the shaft 12 of the device 10, as shown in
In other embodiments, from a transverse view, the large radiused edge portion 26 of the loop element 18 can be angled at an angle α that is from about 5 to 45 degrees relative to the longitudinal axis L of the shaft 12 of the device 10, as shown in
In these embodiments, the axial deployment length at full deployment of the loop elements 18 is relatively short when compared to some prior art devices which resemble the intermediate deployment configuration illustrated in
In addition to the axial deployment length, loop elements of prior art devices lack substantially complete circumferential apposition with the vessel wall, which makes it difficult to retrieve objects near the periphery of the blood vessel lumen. In contrast, embodiments of the snare disclosed herein achieve substantially complete circumferential apposition which facilitates retrieval of objections, such as retrieval elements on filters, that are located near the periphery of the blood vessel lumen.
One alternate embodiment of the device 10, illustrated in
In some embodiments, the loop elements 18 can be attached to a shaft 12 via a swaged or crimped hypo tube 20. These loop elements 18 can be made of two or more wires, including at least one Nitinol wire and at least one platinum wire. As illustrated in
Another alternate embodiment, as illustrated in
In some embodiments, this design offers several key features and capabilities, for example:
1. Loop Design
The design of the loop elements allows for deployment in different size lumens, and can conform to variations in lumen anatomy such as tapering, curvature, and angulations. This conformance feature can also enable the device to achieve full radial apposition with the target lumen regardless of lumen diameter or circularity. The loop configuration allows the device to catch a foreign object no matter where the object is located within the luminal space, since the loops reach full radial apposition within the lumen. The design of the elements allows the snare to fit into a very small guiding sheath, facilitating navigation through tortuous anatomies. The angled design of the loop radius allows the device to have axial reach both distal and proximal to the point where the loops are attached to the shaft, enabling the loops to locate foreign objects with minimal forward and backward axial manipulation of the device by the user. The non-angled design of the loop radius allows the device to have a flat, single plane circle geometry, enabling the loops to locate foreign objects with which may be against the vessel wall or partially embedded in the vessel wall. The loops can be made radiopaque, which allows visualization of the loop under fluoroscopy. Additionally, each individual loop element can employ a single or plurality of radiopaque markers such that each loop element has a different quantity of radiopaque markers, or a different pattern of radiopaque markers, to allow the operator to visually differentiate and identify each loop element fluoroscopically.
2. Shaft Design
The diameter and mechanical properties of the shaft, such as tensile strength, stiffness and/or elasticity, allows the user to manipulate the loops easily, by transferring axial and torsional motion from the proximal end of the device down to the distal end of the device. The diameter of the shaft allows for it to fit within a small diameter guiding sheath. The diameter of the shaft provides tensile support and strength to allow for high forces that may be required for removing a foreign object from the human anatomy. The shaft can be either solid or hollow, allowing the passage of devices, such as a guidewire, through the shaft. The shaft can be of a single element such as a wire, or a construction of a plurality of elements which are braided or stranded together. The shaft can be of a radiopaque material, to facilitate fluoroscopic visualization.
3. Hypo Tube Design
The inner diameter of the hypo tube allows the loop wires and shaft wire to fit snugly within the inner diameter, to facilitate mechanical swaging, soldering, or crimping of said hypo tube, mechanically locking the elements together. The outer diameter of the hypo tube provides adequate wall thickness to allow mechanical swaging or crimping of the hypo tube to provide a strong mechanical attachment, without cracking the hypo tube. The hypo tube can be of a radiopaque material, to facilitate fluoroscopic visualization. Additionally, the hypo tube can be radially shaped into a non-circular shape, such as but not limited to a hexagon or square or rectilinear shape, to further facilitate mechanical fit and locking of the shaft and loop elements.
In some embodiments, the fundamental design elements which achieve these features include, for example: (1) a plurality of loop elements, which are attached to a shaft via a hypo tube; (2) loops which are designed to be flexible and radiopaque; (3) loops which can be collapsed within a guiding catheter, and deployed outside of the guiding catheter; (4) loops which can reach full circular apposition within the luminal space in a human body; (5) loops which are attached to a shaft distally, which extend laterally towards the wall of the vessel of a human body; (6) loops which are angled relative to the axis of the shaft, typically less than 91 degrees and typically greater than 1 degrees; (7) loops which employ an attachment that is typically a crimped or swaged hypo tube; (8) a shaft which is attached to the loops; (9) a shaft having a diameter allows it to fit within a small diameter guiding catheter; (10) a shaft which can be either solid or hollow; (11) a shaft made of a material which can be polymeric, or can be of a metal such as but not limited to nickel titanium; and (12) a shaft having a length designed to enable the user to position the loops at a desired location to remove a foreign object from a human body.
In some embodiments, the snare device 10 is designed for placement into a guiding sheath 22, being advanced through said sheath 22, deploying near a foreign object located within the human anatomy, capturing said object, and removing the object from the human anatomy. The shape of the loop elements 18 allows them to conform to the diameter of the vessel in which they are deployed into, allowing easier capture of the foreign body with less manipulation.
The device 10 enables a user to capture a foreign object located within the human anatomy, grasp said object in a controlled manner, and retrieve and remove said object from the human anatomy. Examples of foreign objects which might be removed from the human anatomy include implants such as stents, guidewires, leads, filters, and valves, and organic objects such as kidney stones or calcified emboli. For example, a snare 10 can be used to capture a vena cava filter and pull it into a retrieval sheath 22 for removal from the patient.
As illustrated in
As the sheath 22 is advanced over the filter 40, the flexible distal tip portion 32 of the sheath 22 can expand and invert over the filter 40, providing a ramp in which the filter 40 can be drawn into the sheath 22. In some embodiments, the inversion of the distal tip portion 32 can be initiated by contact with specific structures on the filter, such as the retrieval element and/or anchors on the filter frame. In some embodiments, the snare 10 can be retracted in the proximal direction while the sheath 22 is advanced in the distal direction to capture the filter 40 within the sheath 22. In other embodiments, the snare 10 can be retracted in the proximal direction while the sheath 22 is held relatively immobile, i.e. neither advanced nor retracted, to capture the filter 40 within the sheath 22. In some embodiments, the entire filter 40 can be retracted into or captured by the inner sheath.
Another example is the use of a snare 10 to grasp and extract loose kidney stones from a patient's kidneys. The snare 10 is advanced through one or more sheaths 22, up to the site of the loose kidney stone. The snare 10 is then deployed and engaged with the stone. Next, the snare 10 is pulled into the sheath 22, or the sheath 22 advanced over the snare 10, drawing the stone into the distal ID of said sheath 22.
As described above, the retrieval system can include a plurality of different components, such as a guide wire, a snare 10, an inner sheath and an outer sheath 22. The proximal ends of these components are generally located outside the patient's body so that the operator can manipulate each of the components by grasping the proximal portion of the components and moving the component in a proximal or distal direction. Often, the proximal portions or ends of the components are or can be reversibly secured or fixed to one another in a proximal handle portion, using a rotatable or twist fitting, such as a luer lock, for example. Because one hand of the operator is often used to manipulate the component, only one hand is free to disconnect or connect the fittings, which can be difficult to do for a rotatable luer lock fitting. In addition, the twisting or rotation of the twist fitting can lead to unintentional and undesired twisting or rotation of the snare device.
Therefore, it would be advantageous to provide fittings that can more easily be manipulated with one hand, such as a snap fitting, as illustrated in
These snap fittings 100 can be integrated into the proximal ends of the various components described herein, and well as other components that can be used with the retrieval system. Alternatively, the snap fittings 100 can be made into luer lock adaptors, or other connector adaptors such as screw adaptors, that allow the operator to convert a luer lock fitting, or other fitting, into a snap fitting, as illustrated in
In some embodiments, the proximal gripping portions of the components can include an indicator that identifies which component the operator is gripping, thereby reducing the confusion that can occur in locating the corresponding proximal gripping portion for the desired component. In some embodiments, the gripping portion can include a visual indicator. For example, the different components can have color coded gripping portions, or can be labeled with, for example, an easily read symbol or the name of the component. In some embodiments, the gripping portion can include a tactile indicator that allows the operator to distinguish between the different components without having to look at the gripping portions, which allows the operator to maintain visual focus on more important matters, such as real-time imaging of the retrieval system within the patient provided through fluoroscopy. For example, one component can have a smooth gripping portion, another component can have a rough or knurled gripping portion, and another component can have a dimpled or ridged gripping portion. Each component can have a different tactile pattern to provide tactile contrast between the components.
In some embodiments, a pressure sensor and/or an intravascular ultrasound (IVUS) transducer can be added to or incorporated into the delivery system and method. The pressure sensor can be used to measure the pressure at various positions within the vasculature, which can be used to determine blood flow, while the intravascular ultrasound (IVUS) transducer can be used to measure fluid flow and/or provide imaging within the vessel. In some embodiments, the pressure sensor and/or IVUS transducer can be incorporated into the guidewire at one or more locations, such as the distal end or distal portion of a guidewire, as described in U.S. Pat. No. 8,277,386, U.S. Pat. No. 6,106,476 and U.S. Pat. No. 6,780,157 which are hereby incorporated by reference in their entireties for all purposes, as well as being incorporated into intermediate and proximal portions of the guidewire. The guidewire with the pressure sensor and/or the IVUS transducer can be used much like a normal guidewire to help navigate the delivery device through the vasculature, with the added benefit of providing pressure measurements and ultrasound imaging to help in the navigation, to visualize the device placement site, and to monitor and ensure proper device deployment. In some embodiments, the IVUS transducer generates image slices as it is advanced and retracted which can then be assembled together to form a three dimensional reconstruction of the vasculature and/or the device within the vasculature. In some embodiments, the guidewire with the pressure sensor and/or IVUS transducer can be fastened to a catheter in a similar manner to that described below for a catheter having a pressure sensor and/or IVUS transducer that is fastened to another catheter.
In some embodiments, the pressure sensor and/or IVUS transducer can be located on a catheter in a similar configuration to the guidewire. For example, the IVUS transducer can be located on the distal tip of the catheter while the pressure sensor(s) can be located proximally of the IVUS transducer at one or more locations along the catheter body, from the distal portion of the catheter to an intermediate portion of the catheter to the proximal portion of the catheter. The pressure and/or imaging catheter can be used in parallel with the delivery or retrieval device or any other catheter that is inserted into the vasculature. In some embodiments, the pressure and/or imaging catheter can be fastened to the delivery or retrieval device or other catheter by, for example, enclosing both catheters in a sheath or larger catheter or by fusing the two catheters together. For example, U.S. Pat. No. 6,645,152 and U.S. Pat. No. 6,440,077, both to Jung et al. and hereby incorporated by reference in their entireties for all purposes, discloses an intravascular ultrasound catheter joined together in parallel with a vena cava filter delivery device to guide placement of the filter in the vena cava. The pressure and/or imaging catheter can be used for the same purposes as the pressure and/or imaging guidewire.
In some embodiments as illustrated in
Use of the ultrasound imaging system allows the operator to deliver the device without fluoroscopy or using less fluoroscopy, thereby reducing the radiation exposure to the patient, while allowing more accurate evaluation of the vasculature, aiding placement of the device and allowing confirmation that device placement was proper. The imaging can be used to aid in the deployment of the filters or other devices. The imaging can also be used to aid in the retrieval of the deployed devices by providing visualization of, for example, the retrieval features on the deployed device and of the retrieval features, such as loops on a snare, of the retrieval device. The vasculature and implant location can be imaged prior to deployment, after deployment and/or during deployment. The imaging can be used during the retrieval process. The imaging can be used to aid in positioning of the filter or device within the vasculature. The imaging can be used to image the deployment location and determine the appropriate sizing of the filter or other device. The imaging can be used to help estimate treatment duration.
Although an imaging systems described above have been ultrasound based, other imaging systems can be used instead or in addition. For example, the imaging system can be based on intravascular ultrasound (IVUS), Forward-Looking IVUS (FLIVUS), optical coherence tomography (OCT), piezoelectric micro-machined ultrasound traducer (PMUT), and FACT.
In some embodiments, as illustrated in
In some embodiments, as illustrated in
In some embodiments, as illustrated in
In some embodiments, as illustrated in
In some embodiments, as illustrated in
As illustrated in
In some embodiments, the echogenicity of the loop elements 2608 can be increased by employing twists or braids of two or more wires to form the loops. In some embodiments, an echogenic material can be used to coat the loop elements 2608 and other parts of the snare. For example, various echogenic features as described below can be incorporated into the loop elements 2608 and any other feature of the retrieval system 2600. In addition, echogenic materials and features can be incorporated into the filter device, as described below, in order to enhance its retrievability under IVUS imaging.
Filters are more complex structures in contrast to the relatively simple designs found in catheters and needles. In a more complex device like a filter there is a need to identify specific portions within the device during some medical procedures. In addition, it would be advantageous as well to determine the orientation of the device including components within the device to one another (as used for determining deployment, retrieval and the various intermediate stages thereof) as well as the overall filter orientation to the surrounding lumen or vessel. In contrast to the conventional techniques using location of the tip or start or end of the entire length, a more complex structure such as a filter position, orientation or relative placement information would yield specific benefits. In some cases, aspects, portions or attributes of the overall filter or filter components or portions will enable more useful determinations about the filter in relation to the physiological environment. In one aspect, an intravascular ultrasound (IVUS) catheter and processing system or signal processing algorithm is used to confirm filter sizing selection, guidance for filter placement, filter implantation steps, filter and/or vessel measuring using IVUS before during and/or after steps to confirm sizing selection and fit is appropriate under the physiologic environment and for confirmation and/or documentation of proper sizing selection, placement, engagement or degree of engagement of fixation elements (if present), clot burden, orientation and/or deployment in a patient or physician medical record.
In one aspect, embodiments of the present invention are directed toward medical devices having a complex shape or that are configured to move from stowed to deployed configurations that may also have specific orientation and placement criteria for proper use in a lumen, vessel or hollow organ. One such complex device is an IVC filter. Aspects of the present invention include such devices employed within the human body which have enhanced ultrasound visibility by virtue of incorporation of an echogenic material using any of the techniques described herein alone or in any combination.
In one aspect, there are described herein various alternative filter designs for increasing the echogenicity of the filter. A filter with enhanced echogenic characteristics may include one or more than one of: (a) a modification to one or more components of the filter to enhance the echogenic characteristics of the component; (b) formation of dimples into a component surface of sufficient number and scaled to a suitable size, shape, orientation and pattern for use with intravascular ultrasound systems; (c) protrusions formed in, placed on or joined to a filter surface; (d) roughening one or more surfaces of a filter, for example using a chemical process, a laser or bead blasting technique; and (e) altering one or more steps of a filter manufacturing technique to introduce cavities, voids or pockets to locally modify or adapt one or more acoustic reflection characteristics to improve echogenicity in one or more specific regions of a filter. One example of the manufacturing alteration is to introduce gaps between the segments of tubing or coverings whereby the gap provides the echogenic enhancement. In addition, cavities, voids, pockets, dimples, gaps and the like may be left empty or, optionally, filed, partially filed or lined with any of the echogenic materials described herein.
In one aspect, there are provided embodiments of a filter having enhanced echogenic characteristics in or related to at least one or a portion of an proximal end, a distal end, a terminal proximal end, a terminal distal end, a retrieval feature, an atraumatic tip on a retrieval feature, a mid-strut region, a leg or strut portion having at least one orientation attribute to another portion of the filter, an indicia of a location of a fixation element or a retrieval feature, a location on a portion of the filter selected such that in use with a particular fixation element the marker in a location that indicates that the fixation element is fully deployed into a wall of a lumen or portion of a vessel or hollow organ (i.e., the marker is against the lumen wall or nearly so when the fixation element is fully engaged. As such, see the marker against the wall indicates proper deployment, spaced from or not visible would indicate, respectively, not fully engaged or over penetration); a portion of the distal tip and/or an elongated portion. The above described methods may also be applied to the other techniques and alternatives described herein.
In still further embodiments, a portion, component or aspect of an intraluminal filter may have enhanced echogenic attributes by applying a coating or sleeve containing one or more of the echogenic materials disclosed herein or fabricated according to any of the techniques or having any of the attributes to enhance echogenic qualities as described herein. In some aspects, the enhanced echogenic attributes are provided by the incorporation into, application onto or within a component or portion of a filter one or more echogenic materials or echogenic markers in a specific configuration, location, orientation or pattern on the filter.
Enhanced echogenic markers or locations may be devised and placed for use individually or in combinations such as to facilitate the identification to an IVUS system or ultrasound imaging modality an indication or signature for a specific location on a filter, such as, for example, a retrieval feature, a terminal proximal end, a terminal distal end, a location of a fixation element or a location of some other indicia that identifies a specific aspect of a particular filter design. In addition or alternatively, two or more enhanced echogenic markers or portions may be used in combination to provide additional information about a filter such as orientation with in a vessel, confirmation of deployment or a portion of a deployment sequence, confirmation of final placement, confirmation of migration or lack of migration, confirmation of retrieval or progress in a retrieval sequence and the like according to the various processes and used for filters within the vasculature or in lumens of the body. In another specific embodiment, the use of IVUS techniques with embodiment of the echogenic enhanced filters describe herein may also be used to measure the diameter of the vessel at specific device locations indicated by the echogenic markers during or after deployment or retrieval of a filter.
In still further aspects, the use of IVUS techniques with embodiment of the echogenic enhanced filters describe herein may also be used to determine, detect or indicate inadequate dilation, adequate dilation, filter expansion, degree of filter expansion, filter—vessel engagement and degree or engagement, strut/leg/anchor position and other attributes relating to the interaction between the filter and the surrounding physiological environment.
Still further, the echogenic markers are positioned with regard to the likely or planned positioning of the IVUS transducer and/or likely pathways for acoustic energy used by the imaging system. By way of example, if the IVUS transducer is forward looking, then those forward looking aspects of the filter will be provided with the enhanced echogenic aspects. In another example, if the IVUS transducer is cylindrically shaped and will be positioned through the interior portion of a filter then the filter will be provided with enhanced echogenic aspects on interior surfaces or portions that would receive acoustic energy from such as transducer in such a position. Other modifications are within the scope of the invention based on the particular style of IVUS transducer used, the position relative to the filter and the placement and type of echogenic feature incorporated into the filter. Put another way, the echogenic enhancements of the filters described herein are selected, designed and positioned on the filter with regard to the IVUS sensor type, acquisition mode and position relative to the filter. Additional details in the use of IVUS with filters is further described in U.S. Pat. Nos. 6,645,152 and 6,440,077, both of which are incorporated herein by reference in their entirety for all purposes.
In one aspect, the placement and signature of such enhanced echogenic markers are discernible to a human user viewing an ultrasound output alone or in combination with being discernible to a computer system configured for the processing of an ultrasound return including a return from the enhanced echogenic filter. Additional aspects of the formation and use of echogenic materials is made with reference to the following US Patents and Patent Publications, each of which is incorporated herein by reference in its entirety: US 2010/0130963; US 2004/0230119; 5,327,891; 5,921,933; 5,081,997; 5,289,831; 5,201,314; 4,276,885; 4,572,203; 4,718,433; 4,442,843; U.S. Pat. No. 4,401,124; U.S. Pat. Nos. 4,265,251; 4,466,442; and 4,718,433.
In various alternatives, the echogenic material may either be applied to a portion of or a component of a filter in any of a number of different techniques.
In one example, an echogenic component or additive is applied to or incorporated into a filter or portion of a filter as a selective coating applied to a portion or component of a filter.
In one example, an echogenic component or additive is applied to or incorporated into a filter or portion of a filter as a mold formed to be placed over or joined to a portion of component of a filter.
In one example, an echogenic component or additive is applied to or incorporated into a filter or portion of a filter as an extruded sleeve formed in a continuous segment to cover a portion or component of a filter. In one embodiment, one of the inner tubular member or the outer sleeve or coating may be fabricated of a material according to the present invention, having increased echogenicity, with the other of the inner tubular member fabricated of a biocompatible polymer such as polyurethane or silicone rubber, for example.
In one example, an echogenic component or additive is applied to or incorporated into a filter or portion of a filter as a compound or two layer structure comprising an inner tube and an outer tube or sleeve with one or both of the tubes made from or including or incorporating one or more echogenic materials or modifications as described herein. In addition or alternatively one or both sleeves, tubes described herein may include or encapsulate an echogenic marker or component of specific shape or geometry, for example, as in the case of a tube structure having within the sidewall of the tubing a coiled structure. In one aspect, the coiled structure is made from an echogenic material and the windings are provided in a manner that is useful in any of the aspects of the filter described herein. The coil may have a particular size or variation in size, pitch or variation in pitch or other attribute useful in providing an echo identifiable aspect of the filter property being determined. In one specific embodiment, the dimensions of the coil or other echogenic material has dimensions selected for increasing acoustic reflection with regard to the resolution or processing algorithms used in the imaging ultrasound system.
In one example, an echogenic component or additive is applied to or incorporated into a filter or portion of a filter as a braided structure incorporated into a compound or two layer structure comprising an inner tube and an outer tube or sleeve with one or both of the tubes made from or including or incorporating one or more braid comprising echogenic materials or modifications as described herein. In addition or alternatively one or both sleeves, tubes described herein may include or encapsulate an braid formed into an echogenic marker or component of specific shape or geometry, for example, as in the case of a tube structure having within the sidewall of the tubing a braided structure. In one aspect, the braided structure is made from an echogenic material and the braided is a small diameter that is when wound around the tubes or sleeve or directly onto a portion of or component of a filter. The winding pattern and spacing of the braided materials are provided in a manner that is useful in any of the aspects of the filter described herein. The braid may have a particular braid strand composition, structure, size or variation in size, pitch or variation in pitch or other attribute useful in providing an echo identifiable aspect of the filter property being determined. One or more of the strands in the braid may be formed from an echogenic material. One or more of the strands may be formed from a material having improved radiopaque characteristic. One or more of the strands may be formed from a material having both echogenic and radiopaque properties. The strands of a braid may be combined using any of the above described strand characteristics.
In another alternative, in still another example, an echogenic component or additive is applied to or incorporated into a filter or portion of a filter as the a series of short segments placed adjacent to one another along a portion or component of a filter in either a close packed or spaced arrangement. In another embodiment, the spacing or voids between adjacent segments may also be adjusted or selected so as to enhance echogenic capabilities of the filter using the material difference introduced by the spacings or voids.
In another alternative, in still another example, an echogenic component or additive is applied to or incorporated into a filter or portion of a filter as a tubing or sleeve suited to heat shrink operations. In one aspect, there is a manufacturing or assembly steps of sliding one or more sleeves over portion of the filter then apply heat to shrink down the segment about the portion of the filter. In particular, various embodiments provide for the specific placement of such a shrink fit tubing having enhanced echogenic characteristics as described herein. It is to be appreciated that the sleeves, segment or tubes may be provided from or have echogenic modifications or elements incorporated into suitable materials such as, for example, ePTFE, PTFe, PET, PVDF, PFA, FEP and other suitable polymers. Still further, these and other materials may be formed in shapes other than tubes but may also take the form of strands, lines, fibers and filaments to be applied in accordance with the echogenic enhancement techniques described herein. In some embodiments, the tubes or segments applied to a filter may have the same or different composition as well as have the same width or different widths. In one aspect, the width or thickness of a plurality of bands is used to provide a code or information about the filter. The use of echogenic bands of different widths is a marking technique similar to the way that different size and color rings on a resistor are arranged in a pattern to describe the resistor's value.
In another alternative, in still another example, an echogenic component or additive is applied to or incorporated into a filter or portion of a filter is extruded over a portion of or a component of the filter.
In another alternative, in still another example, an echogenic component or additive is applied to or incorporated into a filter or portion of a filter is by bonding an echogenic material or components to the filter using a suitable adhesive or bonding technique.
In any of the above described configurations, the portion or component of the filter may be modified with dimples, grooves, pockets, voids. In other aspects, there may be one or more full or partial circumferential recesses, rings, surface diffraction gratings or other surface features to selectively enhance or provide an echogenic property in that portion of the filter, to aid in or foster the application of the echogenic materials. In still further aspects, any of above described surface modifications may also be used to uniquely identify a portion of a filter or any of the above in any combination.
In still further aspects of any of the above echogenic markers or attributes the thickness of the sleeve or coating or component may decrease at its proximal and distal ends to provide for a smooth outer surface. As yet an additional alternative, a coating, marker or other echogenic material may extend proximally to or closely adjacent to the distal end or the distal end or both of the filter component or filtering device.
In still other alternatives or combinations, some filter design embodiments alter components of the filter to enhance echogenicity such as, for example, material selection to incorporate echogenic materials. Examples of echogenic materials include palladium, palladium-iridium or other alloys of echogenic materials.
In some embodiments, echogenic microbubbles are provided in a portion of a filter to enhance the acoustic reflections of that aspect of the filter. Echogenic microbubbles may be prepared by any convenient means and introduced into the component or portion thereof or by a coating or sleeve or shell or other transferring means or mixed with a polymer or other suitable base compound prior to extension of extrusion, molding casting or other technique. The echogenic microbubbles may be pre-prepared or prepared inside the component or element or marker as appropriate. Aspects of the preparation or use of microbubbles are described in U.S. Pat. Nos. 5,327,891; 4,265,251; 4,442,843; 4,466,442; 4,276,885; 4,572,203; 4,718,433 and 4,442,843. By way of example, echogenic microbubbles can be obtained by introducing a gas, e.g. carbon dioxide, into a viscous sugar solution at a temperature above the crystallization temperature of the sugar, followed by cooling and entrapment of the gas in the sugar crystals. Microbubbles can be formed in gelatin and introduced into a component or portion of a device. Microbubbles can also be produced by mixing a surfactant, viscous liquid and gas bubbles or gas forming compound, e.g. carbonic acid salt, under conditions where microbubbles are formed.
In still further alternatives, there is also the incorporation of dual mode materials (radiopaque and echogenic) into a polymer then used to form part of, be applied or otherwise incorporated with a filter device as described herein. Some of these polymer compounds may be fabricated to enhance aging and shelf life and have other beneficial attributes. In one aspect, a filter or portion thereof includes one or more selected segments that are constructed using visibility materials compounded with one or more polymeric materials that make the selected segments visible using both fluoroscopy and ultrasonic imaging. In one specific example, the visibility material may take the form of tungsten and/or tungsten carbide particles dispersed within a polymeric material. In one specific aspect, the radiopaque and echogenic material includes tungsten and/or tungsten carbide particles distributed within a base polymeric material.
In one embodiment, a portion of or a component of a filter includes or has been modified to have an inner layer including a radiopaque and echogenic material. In one alternative, the radiopaque and echo genic material includes particles distributed within a base polymeric material (i.e., a first polymeric material) including a polyether block amide; and an outer layer including an additional polymeric material (i.e., a second polymeric material). In certain embodiments, the additional polymeric material is a thermoplastic elastomer. Optionally, the additional polymeric material is more resistant to hydrolysis and/or oxidation than the base polymeric material.
In still further aspects, a component, a portion or an element added to a filter may be regarded as an echogenic body member that is a part of an echogenic filter to be sonically imaged. The echogenic body member is at least partially made up of a composite material which is echogenically imageable in the patient, such as by the use of ultrasonic imaging equipment used either within the patient or external to the patient. In one aspect, a composite material includes matrix material with discrete acoustic reflective particles embedded in matrix material. In one aspect, the matrix material is a biocompatible plastic. Examples of suitable plastics may include urethane, ethylene, silicone, polyethylene, tetrafluorethylene. In one aspect, a matrix is a formable, pliable material which may be molded and/or extruded to a variety of shapes, depending upon a specific application. The sound reflective particles are embedded in matrix material. Particles are, by way of example, made of a hard material, such as small glass particles that are solid or filled with an acoustically reflective medium. In one aspect, glass particles having a generally spherical shape forming glass microspheres. Glass microspheres with an outer diameter of about 5 microns is one acceptable size. Other sized particles may be utilized as, for example, ranging between 1 and 50 microns and beyond. Particles sized below the resolution size of the imaging ultrasound system in use may be arranged into patterns of sufficient size and orientation to the acoustic waves that result in a discernible feature by the imaging ultrasound system. Furthermore, the particles do not necessarily have to be spherical, or may be partially spherical. Still further, the shape of the particle could be altered to enhance acoustic reflection by presenting different shapes of particles, sizes of particles and combinations thereof to modify acoustic characteristics of the matrix material. By way of example, the particles may be shaped into an “Ordered array.” “Ordered arrays” can take the form of a macrostructure from individual parts that may be patterned or unpatterned in the form of spheres, colloids, beads, ovals, squares, rectangles, fibers, wires, rods, shells, thin films, or planar surface. In contrast, a “disordered array” lacks substantial macrostructure.
By way of example, an echogenic marker may comprise particles that individually are below the resolution of the imaging ultrasound system. The echogenic marker is the combination of these below imaging ultrasound resolution particles in combination, in 1D, 2D or 3D patterns, in graphic arrays, or in machine readable combinations to make a signature. Based on the specific characteristics of the combination of particles, the acoustic returns from an echogenic marker or combination of echogenic markers may be visually perceptible in a display for interpretation by a user or may be detected and interpreted by one or more acoustic reflection or spectral processing algorithms within a imaging ultrasound processing system.
In one aspect, the echogenic material is fabricated by incorporating nanometer sized particles of sonically reflective materials, for example iron oxide, titanium oxide or zinc oxide into a biocompatible polymer. In one method of fabrication, the acoustically reflective particles are mixed with a powdered thermoplastic or thermosetting material such as a polyether amide, a polyurethane or an epoxy, or polyvinylchloride followed by thermal processing of the mixture to provide a material of increased sonic reflectance which may be applied as a coating on medical devices of the type discussed above or may be incorporated as a structural component of the medical devices as described herein.
In still further embodiments and aspects, the particles included to provide echogenic enhancements may be selected, arranged or incorporated to provide acoustically geometrically tuned nanostructures, microstructures or macrostructures. The particles provided herein are formable in all shapes currently known or to be created for acoustic reflection enhancement. In non-limiting examples, the nano-, micro- or macro-particles are shaped as spheres, ovals, cylinders, squares, rectangles, rods, stars, tubes, pyramids, stars, prisms, triangles, branches, plates or comprised of an acoustically reflective surface or where one or more surfaces is adapted such as by roughening or dimpling or other technique used to alter acoustic reflection properties. In non-limiting examples, the particles comprise shapes and properties such as plates, solid shells, hollow shells, rods, rice shaped, spheres, fibers, wires, pyramids, prisms, or a combination thereof.
In one specific aspect, a partially spherical surface may be provided on the outside and/or the inside of particles, as for example a particle with a hollow spherical space therein. Particles are made up of a different material than the matrix. While desiring not to be bound by theory, it is believed that a spherical shape provides for sound reflections at a variety of angles regardless of the direction from which the ultrasonic sound waves are emanating from, and accordingly, are more likely to reflect at least a portion of the transmitted signal back to the ultrasonic receiver to generate an image. Since many of matrix materials available are relatively ultrasonically transparent in a patient, sound reflective particles provide adequate reflection. The use of a composite, rather than a solution, provides adequate size for acoustic reflection off of the discrete particles embedded in the matrix. As indicated, a variety of materials may be utilized for the sound reflective particles, such as aluminum, hard plastic ceramics, and, metal and/or metal alloys particles, and the like. Additionally, liquids, gases, gels, microencapsulants, and/or suspensions in the matrix may alternatively be used either alone or in combination, so long as they form a composite with the desired ultrasonically reflective characteristic.
Any of the above embodiments, alternatives or filter modifications to enhance echogenic characteristics may also be designed or implemented in such a way as to provide an echogenic identifiable or unique trait or acoustic reflection signature that may be registered by a human operator looking at a display or identified using signal processing techniques of a return containing acoustic reflections from the filter in an imaging ultrasound system. In one example, there is a surface of the filter having one or more echo registerable or identifiable feature, mark or indication in a position useful for determining one or more of: a location of an end of a filter; a location of a fixation element on a filter; a location of a retrieval feature on a filter; an orientation of one or more of a leg, a strut, a filter or an end of a filter relative to another of a leg, a strut, a filter or an end or the orientation of the overall filter to a lumen, vessel or hollow organ in a body. Moreover, in another widely applicable aspect of providing enhanced imaging characteristics to a filter as described herein, the characteristic or modification—however added or incorporated into the filter—enable a filter, a filter component or a specified portion of a filter to be more readily imaged by intravascular ultrasound as described herein. In still another aspect, the characteristics or modification to the filter are oriented and positioned in order to facilitate IVUS imaging via an IVUS probe borne by a filter deployment or retrieval catheter, snare, or other implement provided to facilitate the use of intravascular filters.
Also illustrated in
Echogenic characteristics may be added to each of the sections based on the type of function being measured or characterized. For example, echogenic markers, features or tags may be added to Section A in order to provide, for example: identification of the terminal end, end portion or retrieval portion of a filter. Echogenic characteristics of Section A may also be used for determinations related to Section A specifically or the filter generally of filter position, positioning, attitude within the lumen, localization of the filter within the vasculature and other traits common to the characterization of intravascular devices. For example, echogenic markers, features or tags may be added to Section B in order to provide, for example: identification of the mid strut portion, middle or capture region. Echogenic characteristics of Section B may also be used for determinations related to Section B such as for sizing, centering, symmetry of implantation, placement, apposition of implant to vessel walls, clot burden, deployment status or completion, gauge of filter capacity and/or filter contents as well as filter position, positioning, attitude within the lumen, localization of the filter within the vasculature and other traits common to the characterization of intravascular devices. For example, echogenic markers, features or tags may be added to Section C in order to provide, for example: identification of the rear portion, terminal end, retrieval feature, anchor location or depth of insertion, perforation indication or other aspects of the rear or proximal portion of a filter. Echogenic characteristics of Section C may also be used for determinations related to Section C such as for sizing, centering, symmetry of implantation or placement of legs struts and the like, as well as for determination of wall apposition, anchor penetration or perforation. Still further, the markers or tags may be added to aid in determining or evaluating filter position, positioning, attitude within the lumen, localization of the filter within the vasculature and other traits common to the characterization of intravascular devices.
A filter having enhanced echogenic properties is illustrated in
The filter 10 includes a plurality of elongated legs 16 which are of equal length and are identically configured to each other. The legs 16 are collectively arrayed in a conical geometric configuration so that the legs converge to the apical hub 14, and are symmetrically spaced about a central axis extending through the hub. Each of the legs is of equal diameter over its entire length and is made of a relatively resilient material, such as tempered stainless steel wire or the like. In addition to the echogenic attributes described herein, the legs may be coated with a polymeric, synthetic resin material having anti-thrombogenic properties.
In still other alternative embodiments, there is provided a material capture structure having one or more echogenic enhancements alone or in combination with radiopaque enhancements. In one aspect, the filter structure used in a filter includes both echogenic and radio opaque enhancements.
An one aspect, the filter includes material capture structure in the IVC filter will be viewable under fluoroscopic and ultrasound imaging modalities, including appropriate echogenic characteristics to enhance the view of the status or condition of the material capture structure while using IVUS. Enabling the material capture structure to be viewed will allow the physician to appropriately center and verify placement of a filter.
In one aspect, the filter elements or structures are doped to incorporate one or more of echogenic or radio opaque materials or treatments. In one aspect, the membrane, filaments or strands or other structures used to form the filter structure or webbing of the filter includes a radiopaque material having high echogenic properties, such as tungsten or gold, but not limited to either.
In other embodiments, one or more membranes, filaments or portions of a filament within a material capture structure includes one or more non-metallic echogenic features, such as those described elsewhere in this specification. For example, a membrane or filament or portion thereof may include air pockets either added to the material or by the use of materials with entrained air or gas that are used. Another example may include a membrane with a plurality of holes. In one embodiment, an ePTFE suture has echogenic properties due to air content of the ePTFE material. In other aspects, a suture material or a filament or polymer strand may also include dimpled/roughened/matrix/sponge materials, additives, or modifications to provide or enhance the overall echogenic nature of the suture, filament, material or material capture structure, in whole or in part.
In one aspect, these additional materials may assist the physician in centering or placing a filter within a vessel. In another aspect, this improvement is used in conjunction with IVUS will enable the adequate viewing of the filter portion of the filter and will allow for co-registration of filter placement along with an accurate entry/removal of the catheter through the webbing of the filter.
The advantages of this inventive aspect of a filter include, for example and not limitation, filter placement, accurate representation of filter location, ease of introducing/retracting catheter, more viewable space for more accurate assessments, ability to co-register filter location with IVUS and/or ability to better place filter in desired location.
Still other aspects of the use of the innovative filter include, for example, deployment of filters, positioning of filters, sizing of filters, and estimated treatment lengths as well as suture and/or material capture structure visibility. In still other aspects of the use of the innovative filter include, for example, deployment of a vena cava filter, positioning of an IVC filter, sizing of an IVC filter, and estimated treatment lengths as well as enhanced suture visibility.
In one embodiment, there is an IVC filter delivery system with an enclosed IVC filter. This filter would have a mesh, suture, web or other material capture structure suited to the anticipated filter use. The mesh, suture, web or other material capture structure has one or more components that is doped with a highly radiopaque material for better visibility under flouro and good echogenicity for better viewing under IVUS guidance. In still further alternative embodiments, the techniques described above may be applied to one or more material capture structure described in U.S. Patent Application Publication US 2008/0147111 entitled “Endoluminal Filter with Fixation” filed Jun. 4, 2008 as U.S. patent application Ser. No. 11/969,827, (the “'7111 publication”) incorporated herein by reference in its entirety for all purposes. In one particular aspect, the filament/strand/suture 461 shown in
In some embodiments, the snare handle portion can include snare deployment indicators, such as detents, that allow the operator to easily identify and achieve the different stages of snare deployment described above. For example, the operator can deploy the snare using the snare handle until the snare handle reaches a first indicator, which signifies that the snare is deployed in the first deployment stage. The operator can then further deploy the snare using the snare handle until the snare handle reaches a second indicator, which signifies that the snare is deployed in the second or intermediate deployment stage. Then the operator can further deploy the snare using the snare handle until the snare handle reaches a third indicator, which signifies that the snare is fully deployed. In some embodiments, there is a snare deployment indicator for each stage of snare deployment. In some embodiments, the loop elements of the snare have different configurations in each of the different deployment stages as, for example, described above. For example, deployment indicators can be provided to allow the operator to deploy the snare in stages as described above with respect to
While described in various embodiments for retrieval of filters and other medical devices and objects, the sheath and snare designs may also be used to retrieve other filter devices, other embolic protection devices, and other objects. For example, filter devices and other devices described in commonly assigned, and concurrently filed U.S. Provisional Patent Application Ser. No. 61/586,661 (Attorney Docket Number 10253-701.102) is incorporated herein by reference in its entirety and for all purposes.
It is understood that this disclosure, in many respects, is only illustrative of the numerous alternative filtering device embodiments of the present invention. Changes may be made in the details, particularly in matters of shape, size, material and arrangement of various filtering device components without exceeding the scope of the various embodiments of the invention. Those skilled in the art will appreciate that the exemplary embodiments and descriptions thereof are merely illustrative of the invention as a whole. While several principles of the invention are made clear in the exemplary embodiments described above, those skilled in the art will appreciate that modifications of the structure, arrangement, proportions, elements, materials and methods of use, may be utilized in the practice of the invention, and otherwise, which are particularly adapted to specific environments and operative requirements without departing from the scope of the invention. In addition, while certain features and elements have been described in connection with particular embodiments, those skilled in the art will appreciate that those features and elements can be combined with the other embodiments disclosed herein.
This application claims priority to U.S. provisional application No. 61/794,016 filed Mar. 15, 2013, which is herein incorporated by reference in its entirety. All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. The following patents and patent applications are herein incorporated by reference in their entirety: U.S. patent application Ser. No. 11/969,827 titled, “ENDOLUMINAL FILTER WITH FIXATION” filed on Jan. 4, 2009.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US14/30392 | 3/17/2014 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61794016 | Mar 2013 | US |
