Patent Publication Number: US-2021161546-A1

Title: Methods and apparatus for retrograde percutaneous endovascular filter and embolectomy/thrombectomy device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 15/875,822, filed on Jan. 19, 2018, and incorporates the disclosure of the application in its entirety by reference. 
    
    
     BACKGROUND OF THE TECHNOLOGY 
     Various devices and methods exist to protect distal vasculature from dislodged thrombus (blood clot) and embolus (organized intravascular body) when proximal vascular interventions/surgeries are being performed. Further, multiple methods of removing a thrombus or embolus exist including open surgical intervention. Distal embolization caused by peripheral arterial disease (PAD) interventions are a significant cause of morbidity following PAD endovascular revascularization. There are various devices and techniques to prevent emboli and blood clots from traveling within the vasculature such as the use of deployable basket filters that are deployed in the antegrade (in the direction of blood flow) approach along a guide wire inserted into a target vessel or lumen. Some of these devices actively attempt to displace and catch thrombus and emboli while others are positioned to catch any masses that are dislodged during a separate arterial intervention procedure. Some of these filter devices are designed to be left in place but may dislodge and be carried downstream where they can form a blockage themselves. Another common trait to each of these efforts is that they are deployed in the same direction as blood flow through the vessel or lumen. This arrangement may reduce the effectiveness because antegrade approaches for device positioning and deployment necessitates crossing the donor site of emboli/thrombus, thereby causing inadvertent distal embolization. For this reason, traditional antegrade mechanisms of embolic protection are often causing the problem they are designed to protect against. Further, traditional deployment system mechanisms are often prone to failure, resulting in additional procedures and open surgery to remove irretrievable or lost filter devices. 
     SUMMARY OF THE TECHNOLOGY 
     Methods and apparatus for a percutaneous retrograde endovascular filter and embolectomy/thrombectomy device (RET-D) according to various aspects of the present technology include a constraining sleeve housing a deployable filter and a set of closure struts positioned at the end of a flexible tube. The RET-D is deployed into a target vessel in retrograde fashion through a conventional hemostasis sheath such that the open end of the filter engages the antegrade flow of blood. The closure struts are configured to prevent loss of filtered debris when the filter is closed according to where the closure struts are positioned relative to an end of the constraining sleeve. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present technology may be derived by referring to the detailed description and claims when considered in connection with the following illustrative figures. In the following figures, like reference numbers refer to similar elements and steps throughout the figures. 
         FIG. 1A  representatively illustrates a filter device in a semi-open position in accordance with an exemplary embodiment of the present technology; 
         FIG. 1B  representatively illustrates the filter device in a closed positioned in accordance with an exemplary embodiment of the present technology; 
         FIG. 2A  representatively illustrates a set of struts in the semi-open position in accordance with an exemplary embodiment of the present technology; 
         FIG. 2B  representatively illustrates the set of struts in the closed position in accordance with an exemplary embodiment of the present technology; 
         FIG. 3  representatively illustrates percutaneous access into a target vessel in retrograde fashion in accordance with an exemplary embodiment of the present technology; 
         FIG. 4  representatively illustrates insertion of a hemostasis sheath and dilator in accordance with an exemplary embodiment of the present technology; 
         FIG. 5  representatively illustrates removal of the dilator in accordance with an exemplary embodiment of the present technology; 
         FIG. 6  representatively illustrates insertion of the RET-D into the hemostasis sheath using a sliding constraining sleeve in accordance with an exemplary embodiment of the present technology; 
         FIG. 7  representatively illustrates retrograde positioning of the RET-D, constrained within the hemostasis sheath in the target vessel in accordance with an exemplary embodiment of the present technology; 
         FIG. 8  representatively illustrates the filter device in a deployed position in accordance with an exemplary embodiment of the present technology; 
         FIG. 9  representatively illustrates the filter device in a partially withdrawn position in accordance with an exemplary embodiment of the present technology; and 
         FIG. 10  is a flowchart of the process of using the filter device in accordance with an exemplary embodiment of the present technology. 
     
    
    
     Elements and steps in the figures are illustrated for simplicity and clarity and have not necessarily been rendered according to any particular sequence. For example, steps that may be performed concurrently or in a different order are illustrated in the figures to help to improve understanding of embodiments of the present technology. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The present technology may be described in terms of functional block components and various processing steps. Such functional blocks may be realized by any number of hardware components configured to perform the specified functions and achieve the various results. For example, the present technology may employ various materials, needles, wires, injectable devices, dilators, ports, and the like, which may carry out a variety functions. In addition, the present technology may be practiced in conjunction with any number of applications, and the system described is merely one exemplary application for the technology. 
     Referring now to  FIGS. 1A and 1B  a percutaneous retrograde endovascular filter and embolectomy/thrombectomy device (RET-D) according to various aspects of the present technology may comprise a constraining sleeve  118  housing a filter device  100  in a constrained manner. The filter device  100  may be suitably configured to slide within the constraining sleeve  118  such that the filter device  100  can be extended out the end of the constraining sleeve  118 . The filter device  100  may comprise a flexible tube  106  having a filter  104  at a first end and a set of deployable struts  102  arranged peripherally around the filter  104 . The filter device  100  may comprise any suitable filtering system or apparatus to capture a thrombus (blood clot) or embolus (unattached mass) in a target vessel such as an artery or vein. 
     Referring to  FIGS. 3 and 4 , the filter device  100  may be deployed into a target vessel  300  by any suitable method or process. In an exemplary embodiment, the filter device  100  is installed percutaneously (through the skin) into the target vessel  300  in retrograde fashion (opposite blood flow) through a standard hemostasis sheath  402 . A series of tear away sheaths and other commonly known percutaneous access devices such as needles, vascular dilators, and guide wires may be utilized to position and deploy the filter device  100 . 
     Referring now to  FIGS. 1A, 1B, and 8 , once the filter device  100  is positioned in the target vessel  300 , the filter  104  filters an oncoming blood supply. The filter  104  may comprise any suitable material or combinations of materials suitable for use inside the human body such as natural or synthetic polymers or metal alloys that are suitably configured to allow blood flow  804  to pass while filtering out particles greater than a desired size. For example, in one embodiment, the filter  104  may comprise a material such as nitinol mesh configured to filter out particles greater than five to ten percent of diameter of distal vasculature. In an alternative embodiment, the filter  104  may comprise a polymer such as a porous polytetrafluoroethylene (PTFE) matrix configured to filter out particles greater than five to ten percent of the diameter of distal vasculature. In an alternative embodiment, the filter  104  may comprise a synthetic or metallic mesh configured to filter out particles greater than the diameter of five to ten percent of distal vasculature. 
     The filter  104  may comprise a flexible body having a base  108  disposed at the first end of the flexible tube  106  and an open end  116  opposite the base  108 . The filter  104  may be configured to move from an initially constrained state prior to deployment ( FIG. 6 ), to a fully open state during deployment ( FIG. 8 ), and finally to a closed state after a filtering procedure is completed ( FIG. 9 ). 
     In the deployed position, the open end  116  of the filter  104  may expand outwardly from a central axis  120  of the filter device  100  to the inner wall of the target vessel  300  to direct the oncoming blood flow  804  into an inner surface of the filter  104 . Filtered blood  802  may pass through the filter  104  and any thrombus or emboli  800  contained in the blood flow  804  may be captured by the filter  104  and directed towards the base  108 . The base  108  is open to the flexible tube  106  and may allow for the collected thrombus or emboli  800  to be aspirated through the flexible tube  106 . 
     Referring now to  FIGS. 1B and 9 , the filter  104  may be closed upon the completion of the filtering procedure to prevent any collected material that hasn&#39;t been aspirated from moving out of the filter  104  and back into the target vessel  300 . For example, the open end  116  may be moved away from the inner wall of the target vessel  300  and back towards the central axis  120  in a manner that closes the open end  116  while leaving a space between the open end  116  and the base  108  partially expanded to form a tulip shape. Collected material may be retained in the tulip shaped area while the closed open end  116  prevents the collected material from escaping the filter device  100  during removal. 
     Referring to  FIGS. 1A, 1B, 6, and 7 , the flexible tube  106  slides relative to the constraining sleeve  118  to position and retrieve the filter  104 . The flexible tube  106  may comprise any suitable system or device deploying and withdrawing the filter  104  from the constraining sleeve  118 . For example, the flexible tube  106  may be configured similarly to the hemostasis sheath  402  and may be made of similar materials. 
     The first end of the flexible tube  106  may comprise the filter  104  and the set of deployable struts  102 . A second end of the flexible tube may comprise an aspiration port  604  used to remove collected thrombus or emboli  800  from the filter device  100 . 
     Referring now to  FIGS. 1A, 1B, 2A, and 2B , the set of deployable struts  102  act to open and close the open end  114  of the filter  104 . The set of deployable struts  102  may comprise any suitable device for assisting with the opening and closing of the filter  104  and may provide some support to the filter  104  during the filtering procedure. In one embodiment, the set of deployable struts  102  are arranged peripherally around the filter  104  and may be positioned between the filter  104  and an inner wall of the constraining sleeve  118  prior to deployment. 
     The set of deployable struts  102  may comprise any suitable number of individual struts  102 . The number of struts  102  may be selected according to any suitable criteria such as a diameter of the target vessel  300  or an expected blood pressure at the deployment location. For example, in one embodiment, the set of deployable struts  102  may comprise between three and seven individual struts  102  equally spaced around the periphery of the filter  104 . 
     The set of deployable struts  102  may comprise any suitable material such as a stainless steel wire formed in a predetermined shape. For example, and referring now to  FIGS. 1A and 2A , in one embodiment, each strut  102  from the set of deployable struts  102  may comprise a memory wire made of nitinol. Each strut  102  may comprise a lower section  110  that extends outwardly away from central axis  120  and the base  108  of the filter  104  to a mid-portion  112 . An upper section  114  of each strut  102  may extend inwardly from the mid-portion  112  towards the central axis  120  to an end  202 . The end  202  of each strut  102  may be coupled or otherwise connected to a section of the open end  116  of the filter  104 . 
     Accordingly, the set of deployable struts  102  may be configured to open and close the filter  104  according to their position relative to the constraining sleeve  118 . For example, referring to  FIGS. 1A, 2A, and 8 , when the filter device  100  is extended out of the constraining sleeve  118  to the deployed position, the set of deployable struts  102  expand outwardly away from the central axis  120  to a diameter that is greater than that of the constraining sleeve  118 . As the ends  202  of each strut  102  expand outward and away from each other, they cause the open end  116  of the filter  104  to also extend outwardly away from the central axis  120  thereby opening the filter  104  and exposing an inner surface of the filter  104  to the oncoming blood flow  804 . The lower section  110  and mid-portion  112  may provide support to the filter  104  to prevent the filter from collapsing or being carried away under the pressure of the passing blood flow  804 . 
     Referring to now  FIGS. 1B, 2B, and 9 , when the filter device  100  is partially withdrawn back into the constraining sleeve  118 , a section of each strut  102  between the lower section  110  and the mid-portion  112  comes into contact with the end of the constraining sleeve  118 . As the filter device  110  is drawn into the constraining sleeve  118 , forces applied to the struts cause the upper section  114  to move back towards the central axis  120  until the ends  202  of each strut  102  meet closing the filter  104 . Once the open end  116  of the filter  104  is closed, the mid-portion of each strut  102  is contracted to a second diameter approximate that of the constraining sleeve  118 . 
     The constraining sleeve  118  houses a portion of the filter device  100  in a constrained state until deployment. The constraining sleeve  118  may comprise any suitable device or system configured to be partially inserted into the hemostasis sheath  402  and allow the filter device  100  to slide along its interior to facilitate deployment and withdrawal of the filter device  100 . The constraining sleeve  118  may comprise an insertion end  602  enclosing the filter  104  and the deployable struts  102  and a second end  606  with a cuff lumen extending between the insertion  602  and the second end  606 . The flexible tube  106  of the filter device  100  may extend out of the second end  606  of the constraining sleeve  118 . 
     In operation and referring now to  FIGS. 3-10 , a percutaneous thrombectomy procedure may be performed by identifying a target vessel  300  and inserting an access needle  302  into an interior of the target vessel  300 . A guide wire  704  may be inserted through the access needle  302  and into the target vessel  300  ( FIG. 3 ) ( 1002 ). The access needle  302  may then be removed and dilation of the target vessel  300  may be performed by sliding a hemostasis sheath  402  over the guide wire  304  and positioning a dilator  404  over the guide wire  704  and then into the lumen of the hemostasis sheath  402  through the insertion end and subsequently into the target vessel  300  ( FIG. 4 ) ( 1004 ). 
     The dilator  404  may then be removed from the target vessel  300  by sliding it outwardly away from hemostasis sheath  402  ( FIG. 5 ) leaving the guide wire  304  and hemostasis sheath  402  in place ( 1006 ). 
     The constraining sleeve  118  containing the filter device  100  is then positioned over the guide wire  304  and slid into the hemostasis sheath  402  ( FIG. 6 ) ( 1008 ). The constraining sleeve  118  extends partially into the hemostasis sheath  402  ( FIG. 7 ). The flexible tube  106  is then used to deploy the filter  104  by sliding the filter  104  and deployable struts  102  out from the end of the constraining sleeve  118  and into the target vessel  300  ( FIG. 8 ) ( 1010 ). 
     Upon completion of the filtering procedure, the filter  104  and the deployable struts  102  may be partially withdrawn back into the constraining sleeve  118  such that the lower end of the deployable struts  102  abut the insertion end of the constraining sleeve  118  causing the filter  104  to close ( FIG. 9 ) ( 1014 ) in a manner that prevents spillage of filtered embolic debris. The filter device  100  may then be withdrawn from the target vessel  300  through the hemostasis sheath  402  ( 1016 ). 
     These and other embodiments for methods of filtering a material flowing through a lumen may incorporate concepts, embodiments, and configurations as described above. The particular implementations shown and described are illustrative of the technology and its best mode and are not intended to otherwise limit the scope of the present technology in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in a practical system. 
     The technology has been described with reference to specific exemplary embodiments. Various modifications and changes, however, may be made without departing from the scope of the present technology. The description and figures are to be regarded in an illustrative manner, rather than a restrictive one and all such modifications are intended to be included within the scope of the present technology. Accordingly, the scope of the technology should be determined by the generic embodiments described and their legal equivalents rather than by merely the specific examples described above. For example, the steps recited in any method or process embodiment may be executed in any order, unless otherwise expressly specified, and are not limited to the explicit order presented in the specific examples. Additionally, the components and/or elements recited in any apparatus embodiment may be assembled or otherwise operationally configured in a variety of permutations to produce substantially the same result as the present technology and are accordingly not limited to the specific configuration recited in the specific examples. 
     Benefits, other advantages and solutions to problems have been described above with regard to particular embodiments; however, any benefit, advantage, solution to problems or any element that may cause any particular benefit, advantage or solution to occur or to become more pronounced are not to be construed as critical, required or essential features or components. 
     As used herein, the terms “comprises”, “comprising”, or any variation thereof, are intended to reference a non-exclusive inclusion, such that a process, method, article, composition or apparatus that comprises a list of elements does not include only those elements recited, but may also include other elements not expressly listed or inherent to such process, method, article, composition or apparatus. Other combinations and/or modifications of the above-described structures, arrangements, applications, proportions, elements, materials or components used in the practice of the present technology, in addition to those not specifically recited, may be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters or other operating requirements without departing from the general principles of the same. 
     The present technology has been described above with reference to an exemplary embodiment. However, changes and modifications may be made to the exemplary embodiment without departing from the scope of the present technology. These and other changes or modifications are intended to be included within the scope of the present technology, as expressed in the following claims.