KR20220119007A - Absorbent Vascular Filter - Google Patents

Abstract

An absorbent vascular filter for placement in a blood vessel for the temporary filtration of bodily fluids is disclosed. Embodiments are configured to filter the embolism by placing such an absorbable vascular filter in the inferior vena cava (IVC) for the prevention of pulmonary embolism (PE) for a limited time. Once protection from PE is complete, the filter is biodegradable according to a planned schedule determined by the absorption properties of the filter components. Thus, temporary resorbable vascular filters also circumvent the removal requirements of metal recoverable IVC filters while avoiding the long-term complications of permanent IVC filters such as increased deep vein thrombosis, filter breakage, and perforation of adjacent organs due to embolization.

Description

Absorbent Vascular Filter

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to CIP Patent Application No. 16/659,536, filed on October 21, 2019, which is filed electronically on February 23, 2012 by Mitchell Eggers, "Absorptive It is a continuation-in-part of U.S. Patent Application Serial No. 13/403,790, entitled "Vascular Filter," which is a continuation-in-part of U.S. Patent Application Serial No. 13/, entitled "Vascular Filter Stent," by Micelle Gus, electronically filed on April 28, 2011. 096,049, which is a continuation-in-part of U.S. Patent Application Serial No. 13/036,351, entitled "Absorbable Vascular Filter," to Micelle Gus, electronically filed on February 28, 2011 in the U.S., all of which are incorporated in their entirety. is expressly incorporated herein by reference.

field of invention

FIELD OF THE INVENTION [0002] The present invention relates generally to vascular filters, and more particularly to an absorbent vascular filter disposed within a blood vessel for the temporary filtration of bodily fluids. Embodiments are configured to place such an absorbable vascular filter within the inferior vena cava (IVC) for the prevention of pulmonary embolism for a specified period of time determined by the absorbent properties of the filter.

background of the invention

[0003] Pulmonary embolism (PE) kills 100,000 to 300,000 Americans each year - more than breast cancer and AIDS combined - and is the third leading cause of death in the United States [1-5]. A similar incidence of PE was found in Europe, resulting in approximately 370,000 deaths per year [6]. Moreover, PE is the third most common cause of death in trauma patients who survived the first 24 hours. Approximately 25% of all hospitalized patients have some form of deep vein thrombosis (DVT), which is often unclear clinically unless PE develops [7]. On average, 33% of DVT will progress to symptomatic PE, of which 10% will be fatal [6].

[0004] The US Surgeon General recognized this surprising statistic and published a formal Call to Action to Prevent DVT and PE in 2008 [1]. Unfortunately, DVT/PE affects the elderly disproportionately, in part due to prolonged inactivity after medical treatment. The incidence rate is relatively low in those under 50 (1/100,000), and exponentially reaches 1000/100,000 by the age of 85 [8]. Consequently, the US Surgeon General declared that, in the absence of better prevention, the increase in DVT/PE cases due to the aging of the US population could outstrip the population growth [1].

[0005] Risk factors for PE arising from DVT follow Virchow's Triad [9]: (i) endothelial damage, (ii) hypercoagulant, and (iii) hemodynamic changes (congestion or vortex). . Therefore, certain risk factors include hip and knee arthroplasty, abdominal, pelvic and limb surgery, pelvic and iliac fractures, prolonged hospitalization and prolonged immobility such as air travel, paralysis, advanced age, pre-DVT, cancer, obesity, COPD, diabetes and CHF. Orthopedic surgeons are particularly concerned because patients have a 40%–80% risk of DVT and PE after knee and hip surgery without prophylactic treatment [10–12].

[0006] The American Academy of Orthopedic Surgeons (AAOS) has published guidelines for PE prevention. Basically, standard-risk patients should consider chemopreventive agents such as aspirin, low molecular weight heparin (LMWH), synthetic pentasaccharides, or warfarin in addition to mechanical prophylaxis during and/or immediately after surgery [13].

[0007] Aspirin exhibits a relative risk reduction of 29% in symptomatic DVT and a relative risk reduction of 58% in fatal PE [14]. LMWH reduces the risk of DVT by 30% and has been proven to be more effective than unfractionated heparin in high-risk groups such as hip and knee arthroplasty [7]. Warfarin was started within 24-48 hours of initiation of heparin for the purpose of achieving an International Normalized Ratio (INR) result of 2 to 3, and secondary thrombus prophylaxis for 3 months compared with placebo for recurrent venous thromboembolism (VTE). This is because it reduces the risk of the disease by 90% [15,16]. Mechanical prophylaxis, which consists of a pneumatic compression device that repeatedly compresses the leg with an air bag, is also used in conjunction with anticoagulants to reduce the incidence of PE.

[0008] The duration of prevention depends on the cause of the potential DVT. Current recommendations for prevention consist of a minimum of 7-10 days for moderate to high-risk surgery and a maximum of 28-35 days for many orthopedic surgeries. In particular, in the case of orthopedic trauma, prevention of DVT resulted in uptime (32%), hospitalization (19%), postoperative 3 weeks (16%), postoperative 6 weeks (27%), and in rare cases >6 weeks (7%). continues until [17]. Studies have shown that in 80% of trauma patients, hypercoagulability persists for at least one month after injury [18]. For total knee and hip arthroplasty and cancer surgery, a 35-day prophylactic treatment is recommended [12, 19]. Overall, prophylactic treatment for possible VTE is often warranted for up to 6 weeks after trauma or major surgery.

[0009] Contraindications to chemopreventive therapy include active bleeding, hemorrhagic constitution, hemorrhagic stroke, neurological surgery, excessive trauma, hemothorax, pelvic or lower extremity fracture with intracranial hemorrhage, discontinuation of anticoagulation, and recent DVT/PE patients. including those undergoing surgery.

[0010] In patients where the above-mentioned anticoagulant prophylaxis is contraindicated or anticoagulant therapy has failed, AAOS, the American College of Physicians, and the British Committee of Standards in Haematology all have the inferior vena cava ( IVC) filters are recommended [13, 20, 21]. These intravascular metal filters are placed in the IVC through a catheter, essentially trapping the emboli that occurs in DVT before reaching the lungs and resulting in PE. In addition, the British Committee for Hematology Standards recommends placement of IVC filters in pregnant women who are contraindicated in anticoagulant use and who develop extensive VTE just before delivery (within 2 weeks).

[0011] The Eastern Association for Surgery of Trauma further recommends the placement of prophylactic IVC filters in trauma patients at high risk of bleeding and long-term immobilization [22]. These prophylactic recommendations follow studies showing low PE rates in patients with severe multiple trauma who underwent IVC placement [23-25]. In fact, from 49,000 in 1999 to 167,000 in 2007, the fastest growing indicator for total IVC filter usage is the market for prophylaxis using recoverable IVC filters, expected to be 259,000 units in 2012 [26, 27].

[0012] Exemplary vascular filters primarily for IVC placement are described in US Pat. Nos. 4,425,908; US Pat. No. 4,655,771; US Pat. No. 4,817,600; US Patent No. 5,626,605; US Patent No. 6,146,404; US Patent No. 6,217,600 B1; US Patent No. 6,258,026 B1; US Patent No. 6,497,709 B1; US Patent No. 6,506,205 B2; US Patent No. 6,517,559 B1; US Patent No. 6,620,183 B2; US Patent Application Publication No. 2003/0176888; US Patent Application Publication Nos. 2004/0193209; US Patent Application Publication No. 2005/0267512; US Patent Application Publication No. 2005/0267515; US Patent Application Publication No. 2006/0206138 A1; US Patent Application Publication No. 2007/0112372 A1; US Patent Application Publication No. 2008/0027481 A1; US Patent Application Publication No. 2009/0192543 A1; US Patent Application Publication No. 2009/0299403 A1; US Patent Application Publication No. 2010/0016881 A1; US Patent Application Publication No. 2010/0042135 A1; and US Patent Application Publication No. 2010/0174310 A1.

[0013] IVC filter efficacy has been demonstrated in several class I and II evidence studies [22, 28-30]. Most of the initial filters installed are expected to be permanent fixtures, as endothelialization occurs within 7-10 days, so most models require removal without irreversible vascular damage leading to life-threatening bleeding, dissection of the IVC, and thrombosis. It was unrealistic. Although these permanent filters prevented PE, it has been shown to actually increase the risk of DVT recurrence over time.

[0014] In particular, a Cochrane review of the use of IVC filters for the prevention of PE [31] refers to a level I randomized prospective clinical trial by Decousus et al. [32], where the IVC filter population The incidence of DVT increased nearly twofold in 12% (p = 0.02) in the unfiltered LMWH cohort, and (ii) 36% vs. 36% incidence of recurrent DVT in the 8-year filter cohort. 15% in the unfiltered group (p = 0.042) [33]. However, the filter reduced the occurrence of PE; In the first 12 days, only 1% of the filter population experienced PE vs. 5% PE experience in the unfiltered cohort (p=0.03). There was no statistically significant difference in mortality rates in any period investigated. Clearly, the initial benefit of reduced PE with permanent IVC filters is offset by an increase in DVT with no difference in mortality.

[0015] In addition to the increased incidence of DVT for long-term IVC filter placement, filter occlusion has been reported to occur in 6% to 30%, filter migration (3% to 69%), venous insufficiency (5% to 59%), and Postthrombotic syndrome (13% to 41%) has been reported [34-36]. The incidence of complications from insertion, including hematoma, infection, pneumothorax, vocal cord paralysis, stroke, air embolism, misplaced, tilted arteriovenous fistula, and inadvertent carotid puncture, is 4% to 11% [37].

[0016] More recently, temporary or recoverable IVC filters have been marketed to eliminate the risk of PE once subsided, thus avoiding the many harmful complications of permanent filters. The retrieval filter features flexible hooks, folding components, and non-fixed legs that can be easily retrieved. Unfortunately, these same features resulted in unwanted filter migration, fatigue failure, IVC infiltration, fragment migration into hepatic veins and pulmonary arteries, filter tilt and metal embolism [38-43]. Since 2005, 921 filter adverse events have been reported to the FDA, including 328 device transfers, 146 device detachments (metal embolism), 70 IVC punctures, and 56 filter breakages [44]. Some salvage brands publish surprising failure rates, such as the Bard Recovery filter, which destroys 25% over 50 months, which embolizes the extremities. 71% of embolized destruction of the heart resulted in life-threatening ventricular tachycardia, piezoelectricity, and in some cases sudden death. An alternative recovery model, Bard G2, produced 12% failure over 24 months [45]. The prevalence of such device failure is assumed to be directionally proportional to residence time.

[0017] Because of these failures and other issues, in August 2010, the FDA issued an "FDA mandated that transplant physicians and clinicians who continue to manage patients with recoverable IVC filters published an official communication stating that "recommended to consider removing the filter" [44]. Although these types of recoverable filters are supposed to be removed within a few months, several studies have shown that about 70%-81% of patients wearing recoverable IVC filters fail to return to the hospital to have the filter removed, resulting in hundreds of thousands of recoverable patients. Exposure to life-threatening side effects of long-term deployment of IVC filters [41, 44, 46-48]. These patients refuse to remove the filter if there is no follow-up or complications.

Summary of the invention

[0018] The present invention includes systems and methods for filtering a fluid. Certain embodiments include novel absorbable vascular filters that temporarily prevent pulmonary embolism by trapping and inhibiting emboli within body vessels. Absorbent vascular filters according to certain aspects of the present invention have a number of advantages over all conventional vascular filters including permanent, temporary and selective IVC filters. Most importantly, the absorbent vascular filters disclosed herein slowly biodegrade within the blood vessels on a planned schedule designed by the selection of absorbent filter materials that avoid the requirement of filter removal. Moreover, the absorptive vascular filter element is made of a non-metallic synthetic polymer that does not adversely affect end organs upon carefully planned disassembly, as conventional metallic IVC filters that migrate and often fractionate. It is also likely that the relatively short residence time (months) of the absorbent vascular filter will avoid the paradoxical increase in DVT observed with conventional long-term IVC filters.

Brief description of the drawing
1A is a cut-away isometric view of one embodiment of an absorbent vascular filter comprising stepwise sequential biodegradation of an absorbent capture element.
[0020] Figure 1b shows the capture element of Figure 1a in detail.
1C features the capture element of FIG. 1B at a later time point at which the proximal portion of the capture element has been bioabsorbed/biodegraded.
1D features the capture element of FIG. 1C at a later time point where the proximal and middle sections of the capture element have been bioabsorbed/biodegraded leaving only the distal section.
FIG. 1E shows the complete bioabsorption/biodegradation of the capture element of FIG. 1B at the most distant time point.
[0024] FIG. 2A is a cross-sectional schematic diagram of another embodiment of an absorbent vascular filter that also features a stepwise sequential biodegradation of an absorbent capture element.
[0025] FIG. 2B is an enlarged cross-sectional view of the absorbent trap element of the absorbent filter depicted in FIG. 2A;
[0026] FIG. 2C depicts the capture element of FIG. 2B upon installation of a filter in a vessel.
2D depicts the capture element of FIG. 2C at a later time point where the inner capture ring element has been bioabsorbed/biodegraded.
2E depicts the capture element of FIG. 2D at a later time point where the annular mounted capture ring element has been bioabsorbed/biodegraded.
2F depicts the capture element of FIG. 2E at a later time point where two annular mounted capture elements have been bioabsorbed/biodegraded.
FIG. 2G depicts the capture element of FIG. 2F at a later time point after bioabsorption/biodegradation, with only one annular mounted capture element remaining.
[0031] Figure 2h depicts the capture element of Figure 2b fully bioabsorbed/biodegraded at the most distant time point.
3A is a cutaway isometric view of one embodiment of a vascular filter comprising a plurality of capture elements attached to a stent for filtering material such as an embolus;
[0033] Figure 3b shows the capture element of Figure 3a in detail.
[0034] Figure 4a is an absorbable vascular filter composed of polydioxanone suture sizes 3-0, 2-0, 0 and 1 in a web pattern characterized in that it is sequentially decomposed based on the various diameters and expiration dates of the capture elements. .
[0035] Figure 4b is an absorbable vascular filter composed of polydioxanone sutures of a design similar to the web design of Figure 4a except that only sizes 2-0 are used.
[0036] Figure 4c is an absorbable vascular filter composed of polydioxanone suture size 2-0 in a radial pattern typical of a traditional IVC filter.
[0037] FIG. 4D is an absorbable vascular filter composed of polydioxanone suture sizes 3-0, 2-0, 0 and 1 in a radial pattern featuring sequential disintegration based on the various diameters of the capture element.
5 is a diagram during in vitro testing at 0, 7, 13-22 weeks to reveal sequential degradation of the filter starting at 13 weeks, with 1-2 capture elements dismantled per week and reaching final degradation by week 22; A photograph of the absorptive filter presented in 4a is shown.
6 shows the average load at break (kg/strand) vs. polydioxanone capture elements during in vitro testing. It is a graph of time.
7 shows polydioxanone capture element strength retention as a percentage of original strength vs. original strength. It is a graph of time.
[0041] Figure 8 shows Young's modulus vs. polydioxanone capture element during in vitro testing. It is a graph of time.
9A is a cross-sectional schematic diagram illustrating a method of installing an absorbable vascular filter using a catheter-based system with a filter in compression mode.
[0043] FIG. 9B is a cross-sectional schematic diagram detailing deployment of an absorbable vascular filter using a catheter-based system with a sliding outer sheath to deploy the filter in a fully expanded mode.
[0044] FIG. 9C is a cross-sectional schematic view detailing the removal of a central stabilizing rod or piston used to stabilize an absorbent vascular filter during removal of the outer sheath of a catheter-based installation system.
[0045] Figure 9D illustrates the operation of the absorbent vascular filter in the presence of an embolus in the blood vessel.
[0046] Figure 9e shows the container after complete biodegradation/bioabsorption of the absorbent vascular filter.
[0047] FIG. 10A shows an embodiment of an absorbable vascular filter consisting of a braided or woven stent integrated with a capture basket.
[0048] FIG. 10B is a related plan view of the absorbent vascular filter shown in FIG. 10A.
11 is an enlarged view of a braid or weave of an absorbent element comprising a stent section of an integrated vascular filter;
[0050] FIG. 12 is an enlarged view of a braid or weave of an absorbent element comprising both a stent section and a capture basket for an integrated absorbable vascular filter.
13A is a photograph of an integrated absorbent IVC filter woven with a single synthetic filament.
13B is a longitudinal cross-sectional photograph of the integrated absorptive IVC filter shown in FIG. 13A.
14A is an isometric view of one embodiment of an absorbent vascular filter cut from a generally tubular material, wherein the filter apex is formed by securing a capture element with a filament.
14B is a corresponding isometric view of an embodiment of an absorbent vascular filter cut from a generally tubular material, wherein the filter apex is formed by securing a capture element with a filament.
15A is an isometric view of one embodiment of an absorbent vascular filter cut from a generally tubular material, wherein the filter apex is formed by securing the capture element with a splined end plate.
[0056] FIG. 15B is a corresponding isometric view of an embodiment of an absorbent vascular filter cut from a generally tubular material, wherein the filter apex is formed by securing a capture element with a splined endplate.
[0057] FIG. 16A is an isometric view of one embodiment of an absorbent vascular filter cut from a generally tubular material, wherein the filter apex is formed by securing a capture element with an endplate with an engaging connecting shaft.
[0058] FIG. 16B is a corresponding isometric view of an embodiment of an absorbent vascular filter cut from a generally tubular material, wherein the filter apex is formed by securing a capture element with an endplate with an engaging connecting shaft;
[0059] FIG. 17A is an isometric view of one embodiment of an absorbent vascular filter cut from a generally tubular material, wherein the filter apex is formed by securing a capture element with an endplate.
[0060] FIG. 17B is a corresponding isometric view of an embodiment of an absorbent vascular filter cut from a generally tubular material, wherein the filter apex is formed by securing a capture element with an endplate.
[0061] FIG. 18A is an isometric view of one embodiment of an absorbent vascular filter, wherein the annular element is cut from a generally tubular material and the filter basket is formed from an absorbent filament capture element joined together and secured at the apex with an end plate.
18B is a corresponding isometric view of an embodiment of an absorbent vascular filter, wherein the annular element is cut from a generally tubular material and the filter basket is formed from an absorbent filament capture element joined together and secured at the apex with an end plate; .

DETAILED DESCRIPTION OF THE INVENTION

[0063] Embodiments of the present invention will be described in detail with reference to drawings and photographs, which are provided as illustrative examples to enable those skilled in the art to practice the present invention. In particular, the drawings and examples below are not intended to limit the scope of the present invention to a single embodiment, but other embodiments are possible through exchange of some or all of the elements described or illustrated. Wherever convenient, the same reference numbers are used throughout the drawings to refer to the same or like parts. To the extent that certain elements of these embodiments can be partially or fully implemented using known elements, only those portions of those known elements necessary for an understanding of the present invention will be described, and other portions of these known elements will be described. A detailed description of will be omitted so as not to obscure the present invention. In this specification, an embodiment representing a single component should not be considered limiting; Rather, the invention is intended to cover other embodiments comprising a plurality of identical elements, and vice versa, unless expressly stated otherwise herein. Furthermore, Applicants do not intend for any terminology in the specification or claims to be regarded as having an unusual or special meaning unless explicitly stated otherwise. Furthermore, the present invention includes present and future known equivalents to the elements recited herein by way of illustration.

[0064] With reference to the embodiment shown in Figures 1a-e, the absorbent vascular filter 1 comprises an outer annular element 2 for supporting a plurality of absorbent filter capture elements 30-32, 40-41. include The capture element is intentionally designed to be biologically absorbed and/or degraded in a sequential manner to prevent simultaneous separation of the entire filter causing unintended emboli. Sequential degradation can be controlled by selecting absorbent polymers with different absorption profiles, diameters and/or expiration dates. In addition, the absorbent linkage may be incorporated to serve as a point of separation during absorption. Sequential bioabsorption/biodegradation is illustrated in FIGS. 1B-E , where the degradation starts at the proximal capture element 30 and progresses to the mid-section capture element 31 , and finally fully bioabsorbed as shown in FIG. 1E . /Proceeds to biodegradation.

[0065] Such engineered sequential bioabsorption/biodegradation of capture elements can be achieved with a number of synthetic materials. The goal is to select the absorbent filter material to match the desired filter residence time. According to the previous background section, a filter residence time of 6 weeks would be adequate for an IVC filter to prevent PE after trauma or with major surgery. Synthetic materials that can be used to form the capture element include:

[0066] Polydioxanone (PDO, PDS) - a colorless, crystalline, biodegradable synthetic polymer of multiple repeating ether-ester units. In suture form, PDS II (Ethicon, Somerville, NJ) size 4/0 or less retains 60%, 40% and 35% of its tensile strength at 2, 4 and 6 weeks, respectively. For PDS II sizes 3/0 and above, it retains 80%, 70% and 60% of tensile strength at 2, 4 and 6 weeks, respectively. In addition to providing wound support for 6 weeks, PDS II sutures are fully absorbed within 183-238 days via hydrolysis, making them a strong candidate for IVC filter application. Basically, absorption is minimal during the first 90 days and is essentially complete within 6 months. Finally, PDS has a low affinity for microorganisms and minimal tissue response.

[0067] Polytrimethylene Carbonate (Maxon) - Absorption profile similar to PDS but with slightly higher breaking strength. Maxon (Covidien, Mansfield, MA) retains 81%, 59% and 30% of tensile strength at 2 weeks, 4 weeks and 6 weeks, respectively, and fully hydrolyzes within 180-210 days.

[0068] Polyglactin 910 (Vicryl) - a braided multifilament coated with a copolymer of lactide and glycolide (polyglactin 370). In suture form, Vicryl (Ethicon) size 6/0 or greater retains 75%, 50% and 25% of its tensile strength at 2 weeks, 3 weeks, and 4 weeks, respectively, and fully within 56-70 days. is absorbed

[0069] Polyglycolic acid (Dexon) - similar to polyglactin made from polyglycolic acid and coated with polycaproate. Dexone has a tensile strength and absorption profile similar to polyglactin.

[0070] Poly Glecapron 25 (Monycryl) - a synthetic copolymer of glycolide and e-caprolactone. Ethicon retains 50%-70% and 20%-40% of its tensile strength at 1 and 2 weeks, respectively, and is fully absorbed by days 91-119.

Polylacticoglycolic acid (PLGA) copolymer of the monomer glycolic acid and lactic acid. By adjusting the ratio of lactide to glycolide for polymerization, PLGAs of various shapes and properties can be prepared. Like other synthetic absorbent materials, PLGA is degraded by hydrolysis to an absorption profile depending on the proportion of monomers; The higher the glycolide content, the faster the degradation rate. However, the 50:50 copolymer shows the fastest degradation at 2 months. PLGA exhibits minimal systemic toxicity because the polymer is broken down in the body to produce the normal physiological substances lactic acid and glycolic acid.

[0072] Poly L-lactic acid (PLA) is also a polymer made from lactic acid, but has a significant lifetime. In the soft tissue approximation, PLA remains intact for 28 weeks and is fully absorbed within 52 weeks.

[0073] As an example of manipulating capture elements to disintegrate sequentially after a period of PE protection, proximal capture elements 30, 41 can be fabricated in PDS II size 4/0 (0.15 mm diameter), while intermediate capture Elements 31 and 40 are fabricated to have a size 2/0 (0.3 mm diameter), and finally distal capture element 32 is fabricated to a size 2 (0.5 mm) PDS II suture.

[0074] As an alternative to assembling a plurality of capture elements, the vascular filter may be fabricated from an absorbent or non-absorbent composite mesh. Candidates for mesh capture systems include polypropylene such as C-QUR (Atrium Medical Corp. Hudson NH), polypropylene encapsulated with polydioxanone as in PROCEED (Ethicon, Somerville, NJ), and Bard Sepramesh IP Composite (Davol, Inc., Warwick, RI) polypropylene co-knitted with polyglycolic acid fibers, polyethylene terephthalate (Covidien, Mansfield, MA) as in Parietiex Composite (Covidien, Mansfield, MA) and ePTFE as used in DUALAMESH ( W. Gore & Assoc. Inc., Flagstaff, AZ).

[0075] Absorbable as described above with respect to the annular element 2 in FIGS. Substances or non-absorbent materials may be used. The non-absorbable material will essentially act as a permanent stent, lasting well beyond the lifetime of the absorbent capture element. This can be an important option if you need help keeping your blood vessels open. Both types of annular elements 2 can be integrated with a barb 79 (see FIG. 2 ) to maintain the filter position when deployed. Suitable non-absorbent materials for constructing the annular element include Nitinol, Elgiloy, Phynox, 316 stainless steel, MP35N alloy, titanium alloy, platinum alloy, niobium alloy, cobalt alloy and tantalum wire.

2A -2H illustrate another element of an absorbent vascular filter, wherein the absorbent capture element 60-64 is a simple annular element 2 held against the vessel wall 70 by an optional barb 79. ) is mounted on Here again the annular element 2 can be made of absorbent or non-absorbent material as described above. An enlarged cross-sectional view of the capture element assembly 65 is shown in FIG. 2B . Note that sequential degradation of the capture element is achieved by changing the diameter of the selected absorbent material. For example, the inner capture element 60 may be a PDS II 4/0 (0.15 mm diameter), resulting in the fastest absorption as illustrated in FIG. 2D at time t ₁ , followed by time t ₂ in FIG. 2E . The capture element 61 decomposition at is PDS II 3/0 (0.20 mm diameter), followed by the capture element 62 decomposition at time t ₃ in FIG. 2f is PDS II 2/0 (0.30 mm diameter), followed by FIG. 2g . At time t ₄ the decomposition of the capture element 63 is PDS II 0 (0.35 mm diameter), and finally the decomposition of the last capture element 64 at time t ₅ in Fig. 2h consists of PDS II 1 (0.40 mm diameter). became While these dimensions represent specific examples, any diameter within about 0.1 mm to 0.7 mm will suffice. Overall, a gradual progression of degradation is intentionally designed after a 6-week prophylactic period for trauma and major surgical applications.

[0077] In the embodiment shown in FIGS. 3A and B, the vascular filter 1 includes an outer annular stent 2 for supporting a plurality of extruded filter capture elements 60-64 and maintaining vascular patency. . The capture element is collapsible for catheter-based installation and is intentionally designed to prevent end organ damage. The support stent 2 is shown fabricated as a prosthetic vascular graft supported by a corrugated support structure 3 . These vascular filters, which may be constructed with absorbent or non-absorbable filter capture elements, have a number of advantages over all conventional vascular filters, including permanent, temporary and optional IVC filters. Most importantly, the vascular filter is made of a stent that serves as an annular mount for the capture element in addition to providing vascular patency, and a barbed strut prevents the endothelialization characteristics of the metal filter. Thus, it is likely that the increased incidence of DVT observed with metal IVC filters due to intrinsic vascular damage from metal braces is prevented.

The annular stent element 2 of FIG. 3A serves to maintain vascular patency and support the capture element of the vascular filter in addition to maintaining the intravascular fixed filter position upon expansion. Numerous types of stents commonly used as thoracic endoprostheses are available. Such stents will include Gore TAG, Medtronic Talent and Valiant Systems, and Cook Zenith TX2 System. Specifically, Gore TAG consists of an artificial vascular graft made of a fluoropolymer (expanded polytetrafluoroethylene PTFE and fluorinated ethylene propylene or FEP) bonded to a Nitinol support structure. Alternatively, the stent component of the vascular filter may be nickel-titanium alloy (Nitinol), cobalt-chromium-nickel alloy (Elgiloy), cobalt-chromium-nickel-molybdenum alloy (Phynox), 316 stainless steel, MP35N alloy, titanium alloy , platinum alloys, niobium alloys, cobalt alloys, and tantalum wires can be used to fabricate only supporting structures (without artificial vascular grafts).

[0079] A specific embodiment of a sequentially disintegrating absorbable vascular filter was constructed, tested and evaluated with a variety of polydioxanone sutures (sizes 3-0, 2-0, 0 and 1), and is shown in FIG. 4A. The filter features a higher density of webbing than shown in FIG. 2B to capture smaller emboli. Polydioxanone was a candidate polymer based on its tensile retention and absorption properties demonstrated in lesion approximation action. Tygon long flex life tubing (Saint-Gobain Performance Plastics, Akron, OH) with a 25.4 mm id similar to IVC was used for the vessel wall, where polydioxanone was fabricated with the various filter patterns presented.

[0080] Figure 4a is a webbed trapping element intentionally designed for sequential or staged absorption to prevent simultaneous separation of the entire filter during absorption. Here, polydioxanone strands of various diameters (sizes 3-0, 2-0, 0 and 1) were used to modify the time to complete absorption in addition to modifying the expiration date. Because the absorbent polymer initially breaks at stress points during absorption, the web filter is designed to break down into 8 pieces of length D/2 and 8 pieces of size D/4, where D is the inner diameter of the vessel. The objective is a step-by-step or sequential fractional degradation to minimize free-floating exposure of polymer filter trap elements in circulation. Figure 4b is the same web design, but uses a polydioxanone suture of uniform size for comparison. Figure 4c shows a radial filter design similar to a conventional metal IVC filter, but with sutures of various diameters for sequential absorption. Finally, Figure 4d is a radial design consisting exclusively of polydioxanone sizes 2-0.

[0081] The primary endpoint for evaluating absorbent polymers for vascular filter applications was load to break as a function of time. In addition to the absorbent filter shown in Figure 4, several test cells were fabricated with various absorbent polymer candidates for the interstate tensile tensile test. Polymer characterization was performed using an ADMET eXpert 7601 tensile tester at weekly intervals with MTESTQuattro software (Norwood, MA), adding to the primary endpoint and multiple secondary endpoints of breaking load, stress vs. stress vs. The strain graphs were calculated: (i) maximum stress (tensile strength), (ii) maximum strain (% elongation at break), (iii) energy at break and (iv) Young's modulus. The ADMET machine was operated at a crosshead speed of 3 cm/min and was equipped with a high-resolution 100 lb load cell and a 2KN pneumatic gripper.

[0082] Candidate absorbable polymers (representing entrapment elements) sewn into test cells were embedded in a closed circulatory system designed to mimic human cardiac physiology. Destructive tensile testing was performed by extracting sutures of each size and type by stopping the system at weekly intervals. As a control, the same absorbable suture was immersed in a static buffer bath (StableTemp digital utility bath, Cole-Parmer, Vernon Hill, IL) maintained at 37° C. and also tested weekly. The hypothesis is that the increased thermodynamics of the circulatory system accelerates both the absorption rate of the entrapped element and the loss of tensile strength.

[0083] A closed circulatory system with thin-walled ¾" PVC with od 26.7 mm that fits snugly inside flexible 25.4 mm id Tygon tubing to simulate IVC. The heart of the system is a Harvard Apparatus large format that simulates ventricular action of the heart. Animal pulsatile blood pump (Holliston, MA) The Harvard Apparatus blood pump operated almost continuously (913K L pumping) for 22 weeks with some preventive maintenance.

[0084] Heart rate was adjusted to 60 bpm, stroke volume was 60 to 70 ml, systolic/diastolic duration ratio was 35%/65%, and systolic blood pressure was 120 mmHg (of arterial filter to prevent cerebral and systemic embolism) Simulation conditions) to 5 mmHg (simulation conditions of the IVC filter to prevent PE) were variously adjusted.

[0085] Real-time measurements were available at upstream and downstream sensor manifolds. Upstream sensors of the absorbent filter under test included digital temperature, flow rate (L/min), total flow (L) and pressure (mmHg). Downstream instruments included real-time measurements of % oxygen, total dissolved solids (TDS ppt) and pH. TDS monitoring was included to evaluate absorption byproducts less than 20 microns in size, and a downstream 80 micron inline filter would catch the suture fragments from the filter and test cell.

[0086] The four candidate absorbable vascular filters introduced in FIG. 4 were installed in series along the upstream tubing, while the five test cells containing absorbable sutures for the interstate break test performed downstream sections of the in vitro cardiac testing system. were installed in series. A temperature controlled 288W heating tape was used to maintain 37°C in a closed circulation system. Finally, the circulating fluid was a pH 7.4 phosphate buffer (Invitrogen, Carlsbad, CA) with a similar electrolyte profile to human blood. The buffer was changed weekly to maintain a stable pH.

[0087] The absorption and tensile properties of selected polymers were determined as a function of time until strength degradation competed in both the circulation system and the control bath. The phosphate buffer in the circulatory system was replaced weekly as each pH decreased from 7.4 to an average of 6.6. Buffer was changed only once a month in the control bath due to better pH stability in a static environment. The average flow rate was 4.7 L/min while the oxygen averaged 30% and the TDS was 8.8 ppt.

[0088] A step-by-step or sequential absorption of a web absorbent filter design is illustrated in the collage of FIG. 5 . It is noted that the filter begins to degrade at week 13 and continues in a stepwise fashion, after which only one or two capture elements are lost each week until complete degradation at week 22. The initial failure detected at week 13 was located at a point of high stress in the capture element. Initial failure will occur at the apex because the apex of the capture element mounted on the annular support is subjected to twice as much stress as compared to the base of the capture element. The capture element, which formed a loop extending from the vessel wall to the center of the filter, consisted of polydioxanone sizes 1 and 0 with an expiration date of January 2012, while the shorter capture element, extending to a quarter of the diameter, had a shelf life. It consisted of size 3-0 polydioxanone sutures, January 2015. Since the smaller diameter sutures failed at 17 weeks while the larger diameter sutures broke at 13 weeks, the shelf life appeared to have a greater role in the absorption rate than the diameter of the sutures. The planned decomposition of 8 elements of length D/2 and 8 elements of length D/4 for the web filter actually produced smaller brittle fragments due to fragmentation and fragmentation. In fact, the largest filter element captured from the web design by the downstream 80 um filter exhibited a maximum size fragment of 5 mm x 0.3 mm.

[0089] Perhaps the most important feature under consideration for use in absorbent vascular filters is the absorbent polymer strength retention profile depicted in FIG. 6 for polydioxanone in an in vitro circulatory system. As shown, polydioxanone initially exhibits a moderate strength drop of less than about 5% per week for the first 5-6 weeks, followed by a sharp decline approaching 20% per week thereafter. As a traditional summary during the first 5 weeks of circulation, polydioxanone size 1 maintained a strength of about 10 kg, size 0 maintained 6 kg, size 2-0 maintained 4 kg, size 4-0 maintained 1.5 kg. kg was maintained. Similar results were obtained for the buffer bath control during the first 5 weeks. However, statistical differences were achieved at week 5 (p < 0.014) for size 0, at week 6 (p < 0.021) for sizes 2-0 and 1, and at week 7 (p < 0.011) for size 4-0.

[0090] The proposed filter design uses multiple strands acting as capture elements, so that the embolic load is distributed across the N strands. Thus, assuming the same distribution, the net embolic load that can be accommodated by the filter is N multiples of the load per strand at break. Consequently, a polydioxanone size 2-0 filter with 8 trapping elements fixed on an annular support would accommodate a net embolic load of 32 kg.

[0091] An alternative way to approach the strength retention of polymers is to chart the percentage strength retention as a function of time as shown in FIG. 7 . Here, all polydioxanone sizes slowly lost strength during the first 5 weeks and were rapidly absorbed by 10 weeks to negligible strength. In particular, polydioxanone in the in vitro circulatory system maintains an average strength of 88% at 2 weeks, 85% at 4 weeks and 68% at 6 weeks for sizes 2-0 and larger, whereas Ethicon's in vivo animal tissue approximation The application yielded 80% at 2 weeks, 70% at 4 weeks and 60% at 6 weeks according to the Ethicon product literature.

[0092] For the absorbent filter element, as shown in FIG. 8, the Young's modulus range for polydioxanone is 1.0 - 2.3 GPa. The Young's modulus initially decreased (the polymer became more elastic) with the use of the buffer, reached a minimum at 6 weeks, and then increased to about twice its initial value. This increase in Young's modulus for polydioxanone was further observed during disintegration, indicating increased brittleness as the zero terminal strength was reached. This property can be very advantageous for absorbent filter applications. For example, polydioxanone, when its terminal strength reaches zero and decomposes, splits and breaks into smaller, more brittle fragments, potentially less harmful to downstream organs. Further studies are needed to determine the exact size of distal fragments in vivo and to evaluate potential lung microinfarcts.

[0093] At the conclusion of the in vitro absorbable filter study, polydioxanone captures emboli for at least 6 weeks and absorbs blood vessels with sufficient strength retention to rapidly absorb over the next 16 weeks via hydrolysis to carbon dioxide and water. It seems to be a strong candidate for a filter. In particular, polydioxanone size 2-0 was shown to conservatively maintain a 4 kg load at break per strand for 5 weeks in circulation.

[0094] Thus, a filter incorporating eight capture elements filters out an embolic load of 32 kg; Equally, the embolism would have to deliver 1600 kgmm of energy to pass through the filter and be destroyed, which is very unlikely given that the pressure in the IVC is only 5 mmHg (about 0.1 psi). Moreover, web filter geometries with trapping elements of various diameters and expiration dates can be disassembled in a sequential or stepwise manner to yield 1 or 2 small brittle filter segments (less than 5 mm x 0.3 mm each) circulating weekly from week 14 to week 22. appeared to emit. Together with the FDA-approved, non-allergic and non-pyrogenic proven polydinoxanone, catheterized polydioxanone absorbable vascular filters are likely to be an efficient and effective device for the prevention of pulmonary embolism.

[0095] Installation of the absorbable vascular filter is via intravenous insertion using a catheter requiring only local anesthesia, as illustrated in FIGS. 9A-E . Here the filter is folded and compressed within a delivery catheter comprising a sheath 71 on a central rod and an inner applicator or stabilizer piston 73 as illustrated in FIG. 9A . For IVC filter placement, the delivery catheter is inserted into the patient's vasculature at a convenient location, such as the femoral vein or internal jugular vein. Subsequently, the delivery catheter is fed, typically through the vasculature, through a guide wire until the desired placement position is reached, often below the renal vein. Next, the compression filter 50 is allowed to expand as it slides the sheath 71 in the proximal direction while pushing the stabilizer rod and piston 72 in the distal direction (see FIG. 9B ). Once the sheath 71 is removed from the filter, the stabilizing piston 73 can also be retracted as shown in FIG. 9C . As a result, as the thrombotic event releases the emboli 80, the emboli are captured by the vascular filter and prevent migration to the heart and lungs, thereby preventing potentially lethal PE (see FIG. 9D ). Depending on the desired prophylactic time window for filter use (about 6 weeks for many applications), the filter is bioabsorbed, leaving the blood vessels free of any debris as depicted in Figure 9e.

An alternative embodiment of an absorbent vascular filter 1 having an integrated annular support 102 and capture basket 101 is depicted in FIG. 10A . Here the annular support 102 and capture basket 101 are braided or woven much like a radially expandable stent that can be compressed in a catheter as described above prior to deployment. 10B is a plan view of the absorbent vascular filter showing the weave or braid of the capture basket 101 . The weave is shown holding the clear center 104 to allow insertion of the guide wire during catheter placement. The appeal of this particular embodiment is that the total absorbent vascular filter (annular support and capture basket comprised of a capture element) can be fabricated from a single filament with a radial force designed to prevent filter movement as described below.

), 및 사용된 크기 초과 직경의 양에 의존적인 반지름 방향 힘을 나타내는 직경 확장가능하고 압축가능한 관형 필터를 생성한다. 특히, 반지름 방향 힘을 설정하는데 중요한 각도는 도 11에서

로 표시된다. 각도

가 180°에 가까워 더 클 수록 직조에 의해 제공되는 반지름 방향 힘의 양이 커진다. 전형적으로,

는 둔각이며, 90 내지 180°로 선택된다. [0097] The integrated absorbent vascular filter shown in FIGS. 10A and 10B is an angular pi (

), and a diametrically expandable and compressible tubular filter that exhibits a radial force dependent on the amount of oversize diameter used. In particular, the important angle for setting the radial force is shown in FIG. 11 .

is displayed as Angle

The closer to 180°, the greater the amount of radial force provided by the weave. Typically,

is an obtuse angle and is selected from 90 to 180°.

[0098] For example, a simple cylindrical braided weave (L=7, P=4) is cut lengthwise and laid flat on the surface where the roofing pins 110 and braided filaments 103 are exposed, as shown in FIG. 11 . do. Considering the weave as a series of sinusoidal waveforms of period Pτ (see the bold part of the weave in Fig. 11), where P is the number of looping fins moved during one period of the sinusoid, and τ is the fin-to-fin spacing, the vascular filter An algorithm can be derived to ensure that for a given set of parallel looping pins L that span equidistantly around the perimeter of the intended diameter of , each pin is looped once and the final loop ends at the origin.

사이의 관계를 나타내기 위해 표 1에 제시된 표로 시각화할 수 있다. L/P는 원주 당 횡단하는 정현파의 분수 수를 나타내고, N은 실린더의 원주 주위의 총 회전 수를 나타낸다. 본질적으로, 직조는 최종 정현파가 초기 정현파와 동위상이 되기를 원하는 최종 루프가 달성될 때까지 고정된 증분만큼 위상을 벗어난 정현파를 생성한다. 동위상 조건은 곱 Nx(L/P)가 정수여야 한다. 또한 모든 핀이 루프되도록 하려면 Nx(L/P) 곱에 의해 형성되는 첫 번째 정수가 N = P일 때 발생해야 한다. [0099] The algorithm calculates L, P and angles for any desired number of circumferential loops (L).

It can be visualized with the table presented in Table 1 to show the relationship between them. L/P represents the fractional number of sine waves traversing per circumference, and N represents the total number of revolutions around the circumference of the cylinder. In essence, weaving produces a sinusoid that is out of phase by a fixed increment until a final loop is achieved in which we want the final sinusoid to be in phase with the initial sinusoid. The in-phase condition requires that the product Nx(L/P) be an integer. Also, for all pins to loop, the first integer formed by the product of Nx(L/P) must occur when N = P.

Table 1. Relationship between braid parameters.

는

= 2tan^-1(Pπr/Ll)로 표현될 수 있음이 추가로 입증될 수 있으며, 여기서 r 및 l은 원하는 필터 환형 지지대(102)의 반경 및 길이이다. 표 1에서

를 계산하는 데 사용된 r 및 l 값은 각각 0.625 및 1.5 인치였다. 또한, τ는 관계 Lτ = 2πr 또는 τ = 2πr/L로부터 쉽게 계산된다. [00100] For example, when L = 7 and P = 4, the first integer that appears in the row corresponding to P = 4 of Table 1 is N = 4, so this combination of L, P and N means that all pins are utilized and (top 7, bottom 7), the final weave will provide a successful braid that will terminate at the origin. It can be demonstrated that L must be an odd integer for successful braiding. Angle

Is

It can be further demonstrated that it can be expressed as = 2tan ^-1 (Pπr/Ll), where r and l are the radius and length of the desired filter annular support 102 . in table 1

The r and l values used to calculate the r and l were 0.625 and 1.5 inches, respectively. Also, τ is easily calculated from the relation Lτ = 2πr or τ = 2πr/L.

12 shows another braid combination with L=7 and P=6. It is noted that the first integer shown in the row for P = 6 in Table 1 corresponds to N = 6, so the braid terminates successfully at the origin and all L pins are looped once. 12 further illustrates a method for forming capture basket 101 as a simple continuous extension of a filament beyond annular support 102 . As shown at alternate loop points intersecting across the top of the annular support, conical capture baskets 101 are woven by sequentially engaging loops from adjacent loops 105 and extending the loops to apex 106 . The apex loops from each extension 106 may be joined together to reveal a conical capture basket as shown in FIG. 10B with a distinct central apex 104 . Obviously other braided patterns can be used to create sufficient pattern resolution to capture emboli of the desired size.

> 100°이다. 구체적으로, 환형 지지대와 포획 바스켓이 통합된 흡수성 IVC 필터는 도 13a 및 b에 도시된 바와 같이 단일 10ft 합성 필라멘트(직경 0.5 mm)로 제작되었으며, L = 17, P = 16,

= 102°, l = 1.5", r = 0.625" 및 τ = 0.23"이다. 자체 확장성 IVC 필터는 둔각 직조 각도, 25% 특대 직경(1" IVC 직경에 맞음) 및 넓은 직경 필라멘트(0.5 mm)를 선택하여 IVC에서의 배치를 유지하기에 충분한 반지름 방향 힘을 제공한다. 대안적으로, 단일 연속 필라멘트가 사용될 수 있지만, 상기에서 설명된 통합된 흡수성 혈관 필터는 다중 결합 필라멘트로 구성될 수 있다. [00102] In the example above, only a set of 7 roofing pins were considered for simplicity, but a more probable number useful for absorptive vascular filter for IVC could be 17 or 19,

> 100°. Specifically, the absorbent IVC filter with integrated annular support and trapping basket was fabricated from a single 10 ft synthetic filament (0.5 mm diameter) as shown in FIGS. 13a and b, L = 17, P = 16,

= 102°, l = 1.5", r = 0.625" and τ = 0.23". Self-extensible IVC filter has an obtuse weave angle, 25% oversized diameter (fits 1" IVC diameter) and wide diameter filament (0.5 mm) to provide sufficient radial force to maintain placement in the IVC. Alternatively, a single continuous filament may be used, but the integrated absorbent vascular filter described above may be constructed of multiple binding filaments.

[00103] With reference to the embodiment shown in FIGS. 14A and 14B , the absorbent vascular filter 1 includes a plurality of filter capture elements 110 (eg, similar and/or identical to the capture elements described above). It includes an outer annular element 120 (similar to and/or identical to the annular element 2 described above) for supporting and maintaining position within the blood vessel. The capture element 110 may be configured to capture or retard material flowing in the blood vessel for a limited time. Here both annular element 120 and capture element 110 are laser cut from a generally circular tube of absorbent polymer. This means that the annular element 120 and the capture element 110 form a single piece without joints, seams and/or other attachment points between the annular element 120 and the capture element 110 . The single piece may be a substantially continuous structure with a smooth surface free of protrusions that may be caused by joints, seams, and/or other attachment points. In some embodiments, capture element 110 and annular element 120 may be woven from single strands or fibers or cut from sheets of material. For example, the filter may be cut from a sheet of absorbent polymer film and then formed into a tubular shape. In some embodiments, capture element 110 and annular element 120 may be joined together as separate pieces to form absorbent vascular filter 1 .

[00104] The pattern for an annular element can be determined to produce a desired positive radial force (or a given positive radial force) for a given diameter (or diameters) upon placement via finite element analysis and/or using other methods. It can be designed to create and ensure caval apposition. The proximal end 119 of the annular element 120 includes a corrugated feature 121 (eg, similar to and/or identical to the corrugated feature formed by weaving as described above), while The distal end 122 terminates with a capture element 110 . In some implementations, the annular element has a grid spacing that is less than the grid spacing of the capture elements 110 (eg, the spacing between the members 117 in the annular element 120 is smaller than the spacing between individual capture elements 110 ). (eg, a grid design that creates a spacing between the members 117 of the annular element 120 ). In some implementations, the grating spacing of the annular element 120 is configured such that the filter 1 generates a desired positive radial force as described above. In some embodiments, the grid spacing of the capture elements 110 is configured such that emboli or other particulates of the target size are captured by the filter without interrupting the overall fluid flow through the vessel. In some embodiments, the member 117 of the annular element 120 and/or the capture element 110 has a substantially rectangular cross-section and/or other cross-section that contributes to the radial force and/or capture characteristics of the filter 1 . can have In some embodiments, the member 117 and/or the capture element 110 of the annular element 120 has a radiused, chamfered and/or other shaped edge to facilitate fluid flow through the filter 1 . can have

In some embodiments, the capture element has a distal end 111 that can be secured with an absorbent coupler (eg, a filament) 130 to form a filter apex at the distal end 141 of the filter 1 . to include a loop 113 . In some implementations, the individual loops 113 may be formed along the longitudinal axis of the corresponding capture element 110 . In some implementations, there may be one loop 113 per capture element 110 . The loop 113 may be formed such that the open area 115 of the loop 113 faces the lumen of the filter 1 . The loop 113 and/or the open region 115 may have a generally circular shape and/or other shapes that facilitate closing of the distal end 141 of the filter 1 (eg, as described below). together).

In this example, the absorbent binding filament 130 may be a suture and/or other filament. In some embodiments, the absorbent coupling filament 130 may be pre-threaded and/or otherwise looped through the loop 113 before the filter is implanted (or loaded into a catheter for implantation). The absorbent coupling filament 130 may be configured to move between the expanded configuration 130a and the contracted configuration 130b. In the expanded configuration 130a, the absorbent coupling filament 130 is configured to maintain an open configuration (FIG. 14A) in which the capture element 110 does not confine (or only entraps very large emboli) of the vessel. In the retracted configuration 130b , the absorbent coupling filaments 130 are configured to pull the distal ends 111 of the capture elements 110 towards each other to form a filter. In some implementations, the absorbent coupling filament 130 may be configured to move from the expanded configuration 130a to the retracted configuration in response to a tensile force applied to the end 129 of the filament 130 . In some implementations, the filaments 130 may bind knots 127 and/or other materials that reduce the size of the open ends 135 of the filaments 130 (eg, cause the ends 111 to move toward each other). It may include a tightening mechanism. For example, pulling the end 129 may tighten the slip knot 127 down and close the open end 135 . Other tightening mechanisms are contemplated.

[00107] With reference to the embodiment depicted in FIGS. 15A and B (wherein similar reference numbers correspond to reference numbers in other figures described above), the absorbent vascular filter 1 supports a plurality of filter capture elements 110 and and an outer annular element 120 for maintaining position within the blood vessel. In this exemplary embodiment, the capture element 110 includes a spline feature 151 at the distal end 111 , which is a complementary spline receptacle 131a within the absorbent coupler (eg, endplate) 130 . ) and/or otherwise coupled to form a filter apex. In some embodiments, spline features 151 include a shaped distal end 111 . The shape of the distal end may be configured to engage a corresponding spline receptacle 131a such that the spline feature 151 does not disengage from the receptacle 131a when the filter 1 is deployed and/or in use.

In this example, the spline features 151 comprise a substantially trapezoidal shape. The trapezoidal shape may have a corresponding edge 153 extending circumferentially from the width 155 of a given capture element 110 . This makes the distal end 111 wider than the body 157 of the capture element 110 . This also makes the distal tip 159 of the spline feature 151 wider than the portion of the spline feature 151 that begins to extend from the capture element 110 .

In this example, the corresponding spline receptacle 131a includes a trapezoidal shaped channel configured to receive the spline feature 151 (eg, such that the pieces fit like a puzzle). The receptacle 131a is such that the channel has a narrow end 163 at the proximal side 165 of the coupler 130 , and along the outer surface 161 of the coupler 130 to the distal side 167 of the coupler 130 . It may be positioned about the outer surface 161 of the absorbent coupler 130 to extend in the axial direction. In some implementations, the channel becomes wider as it extends along the outer surface 161 such that the channel has a wide end 169 at or near the distal side 167 (eg, a spline feature 151)). In some implementations, the channel becomes wider as it extends towards the center of the coupler 130 (eg, the shape of the spline feature 151 ) such that the channel has a wide face towards the center of the coupler 130 . to match). This shape may be configured to prevent separation of the spline features 151 and the receptacle 131a during placement and/or operation of the filter 1 . These shapes are not intended to be limiting. Spline features 151 and/or receptacles 131 may have any shape and/or size that permits them to function as described herein.

[00110] In some embodiments, the end plate 130 may include a central aperture 132 for receiving a (eg, cylindrical) radiopaque marker and/or guidewire. The central hole 132 may be round or have other shapes as shown. In some implementations, the central aperture 132 may be located at or near the center of the absorbent coupler 130 and/or at another location. In some implementations, the central aperture 132 may be sized to allow the radiopaque marker to elongate once inserted into the aperture 132 and apply a compressive force to the radiopaque marker. In some implementations, the central hole 132 may be sized to pass through a guidewire.

[00111] In some embodiments, the capture element 110 has a spline feature 151 passing through or near the axial centerline of the filter 1 (without blocking the aperture 132) and a coupler ( 130 may be configured to be bent to be coupled to the receptacle 131a on the opposite side. When the individual capture elements are coupled to the coupler 130 in this manner, the force from the individual capture elements (eg, an attempt to return to a cut state from the tube straight direction) is substantially uniform around the coupler 130 . act (eg, pushing the coupler 130 towards the center of each filter) and prevent any individual spline features from disengaging from their respective channels.

[00112] In some embodiments, the endplate may be attached to the capture element during manufacture when the filter is assembled to the catheter for final deployment and/or at other times prior to the implant procedure.

[00113] With reference to the embodiment depicted in FIGS. 16A and B (where similar reference numbers correspond to reference numbers in other figures described above), the absorbent vascular filter 1 supports a plurality of filter capture elements 110 and and an outer annular element 120 for maintaining position within the blood vessel. The capture element has a loop 171 at its distal end 111 that can be secured to a mating connection shaft 133 within a recessed portion 131b of a coupler (eg, end plate) 130 to form a filter apex. ) is included.

In some implementations, loop 171 may be similar and/or identical to loop 113 described above. In some implementations, individual loops 171 may be formed along the longitudinal axis of the corresponding capture element 110 . There may be one loop 171 per capture element 110 in some implementations, or there may be less than one loop per capture element 110 , such as having a loop on an alternative capture element 110 . The loop 171 may be formed such that the open area 173 of the loop 171 faces the lumen of the filter 1 . Loop 171 and/or open area 173 may have a generally circular shape and/or other shape configured to engage shaft 133 (eg, as described below).

[00115] In some implementations, the shaft 133 may be cylindrical and have a circular cross-sectional shape (shown in FIG. 16A ) and/or the shaft 133 may have a different shape (the shape of the opening region 173 is the shaft). (corresponding to the shape of (133)) may have. In some implementations, the diameter (and/or otherwise size) of the shaft 133 is equal to or slightly greater than the diameter (and/or otherwise size) of the corresponding open area 173 , so that the two loops 171 engage. When doing so, it can be fitted by friction with the shaft 133 . The shaft 133 extends from the proximal surface 183 of the recess 131b. The proximal surface 183 is configured to receive a corresponding surface of the loop 171 .

The recessed portion 131b may be recessed from the outer surface 161 of the coupler 130 . In some embodiments, the recess 131b is formed from a depth (eg, from the outer surface 161 ) that corresponds to the thickness of the capture element 110 (eg, the wall thickness of the tube through which the filter 1 is cut). up to an adjacent surface 183). In some implementations, recess 131b may have an open neck region 181 configured to facilitate engagement between loop 171 and shaft 133 . The open neck region 181 may have a width corresponding to, for example, the width 155 of the capture element 110 . The open neck region 181 may facilitate a flush or near-flush coupling between the capture element 110 and the coupler 130 and/or may have other purposes.

[00117] In some embodiments, the capture element 110 passes through or near the axial centerline of the filter 1 such that the loop 171 passes through the coupler 130 (without blocking the aperture 132). may be configured to be bent to be coupled to the shaft 133 on the opposite side of the . When the individual capture elements are coupled to the coupler 130 in this manner, the force from the individual capture elements (eg, an attempt to return to a cut state from the tube straight direction) is substantially uniform around the coupler 130 . act (eg, pushing coupler 130 towards the center of each filter) and prevent any individual loops from disengaging from their respective shafts (eg, see FIG. 16B ).

[00118] With reference to the embodiment depicted in FIGS. 17A and B (wherein similar reference numbers correspond to reference numbers in other figures described above), the absorbent vascular filter 1 supports a plurality of filter capture elements 110 and and an outer annular element 120 for maintaining position within the blood vessel. In some implementations, the capture element 110 is a distal end of the capture element 110 that can be inserted through an aperture 131c of a coupler (eg, such as an endplate) 130 to form a filter apex. barb features 190 at or near 111 . In some embodiments, hole 131c comprises a cylindrical through hole. In some implementations, the axis of the through hole 131c is aligned with the axis of the coupler 130 , the hole 132 and/or other features of the filter 1 . In some implementations, aperture 131c may have a conical cross-section and/or other cross-section and/or along an axis that is not aligned with the axis of coupler 130 , aperture 132 , and/or other features of filter 1 . may be oriented (eg, such that aperture 131c provides resistance to distal end 111 passing through aperture 131c and/or prevents withdrawal of distal end 111 through aperture 131c ). ).

[00119] In some implementations, individual capture elements 110 may include one barbed feature 190, two barbed features 190, three barbed features 190, and/or a different number of barbs. can have features. The examples in FIGS. 17A and 17B show two barb features 190 on each individual capture element 110 , but are not intended to be limiting. In some implementations, the barb feature 190 includes projections 191 , 195 from the body 157 of the capture element 110 . The protrusions 191 , 195 may include, for example, pointed or near-pointed tips and/or other dimensional shapes. In some implementations, the protrusions 191 and 195 may protrude the same amount. In some implementations, different protrusions 191 , 195 on a given capture element 110 may protrude by different amounts. In some implementations, the protrusions 191 , 195 may protrude in different amounts at different individual capture elements 110 .

[00120] The protrusion 191 may protrude from the body 157 in a radial direction (eg, around the circumference of the filter 1) and/or in other directions. In some implementations, protrusions 191 on different capture elements may protrude from each body 157 in the same radial direction. In some implementations, protrusions 191 on different capture elements may protrude from each body 157 in alternative radial directions and/or other configurations. The protrusion 195 may protrude from the body 157 in the axial direction (eg, along the long axis of the filter 1 ) and/or in other directions. This may, for example, facilitate insertion of the distal end 111 into the aperture 131c and/or may have other purposes.

In some implementations, barb features 190 can include channels 193 between protrusions 191 . Channel 193 may have, for example, a width and/or depth that facilitates engagement with coupler 130 and/or other coupling features. For example, channel 193 may have a width corresponding to the thickness of coupler 130 and/or may have other dimensions. Channel 193 and/or protrusion 191 passes through hole 131c corresponding to first protrusion 191 on given capture element 110 as shown in FIGS. 17A and 17B , but second protrusion 191 . can be configured not to pass through, allowing the channel 193 between the projections 191 to be located in the hole 131c (eg, as shown in FIG. 17B ).

[00122] With reference to the embodiment depicted in FIGS. 18A and B (where similar reference numbers correspond to reference numbers in other figures described above), the absorbent vascular filter 1 supports a plurality of filter capture elements 110 and It includes an outer annular element 200 (similar to and/or identical to the circumferential elements 2 and/or 120 described herein) to maintain position within the blood vessel. The proximal end of the annular element includes a corrugated feature 210 (similar to and/or identical to the corrugated feature 121 described herein), while the distal end 220 includes a loop 221 and/or or other features configured to facilitate securing of the proximal end of the absorbent capture element 110 .

[00123] In some embodiments, as shown in FIG. 18A , capture element 110 may be and/or may include a capture filament. The capture filaments may comprise a plurality of individual filaments linked together and/or the capture filaments may be formed by continuous strands of material. A plurality of absorbent capture elements are connected with adjacent absorbent capture elements to establish a capture basket 100 (eg, similar to and/or identical to the capture basket 101 described above). The capture elements may intersect, wrap around each other, braid together, and/or otherwise engage. The apex of the filter 1 is formed by looping a capture element through a hole 310 in the end plate 300 ( FIG. 18B , eg similar to and/or identical to the end plate 130 described above). An end 141 view 231 of filter 1 (without plate 300 ) is shown in FIG. 18A . As shown in view 231 , the intersecting and weaving of the capture filaments may form a petal structure configured to capture emboli and/or other particulates flowing through the blood vessel. The petal structure may, for example, cover the lumen of the vessel more densely closer to the center of the vessel and less densely towards the outside of the vessel.

[00124] In some embodiments, the capture filament is woven through the peripheral hole 310 of the end plate 300 to form the apex of the filter, while in other embodiments the proximal end of the capture filament is located at the peripheral hole location 310 can be fixed in In some embodiments, the endplate includes a central aperture 132 for receiving cylindrical radiopaque markers and/or guidewires and/or for other purposes.

[00125] While the present invention has been described with reference to specific exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

references

Claims (18)

an absorbent circumferential element for attaching or securing the filter to the blood vessel; and
An absorbent filter comprising a plurality of absorbent capture elements attached to the annular element to trap or inhibit material flowing in a blood vessel for a limited period of time, both the annular element and the capture element being cut from a generally circular tube of absorbent material. Being an absorbent filter. The filter of claim 1 , wherein the at least two absorbent capture elements have a loop located at the distal end that can be secured with an absorbent filament to form a generally conical capture basket. The filter of claim 1 , wherein the at least two absorbent capture elements comprise spline features at the distal end capable of being secured to complementary spline receptacles in the endplate to form a generally conical capture basket. The filter of claim 1 , wherein the absorbent capture element comprises a loop at the distal end capable of being secured to a mating shaft in the end plate to form a generally conical capture basket. The filter of claim 1 , wherein the absorbent capture element includes a barb feature at its distal end that can be inserted through an aperture in the end plate to form a generally conical capture basket. The filter of claim 1 , wherein the absorbent capture element includes a loop at its distal end capable of being secured to a mating shaft in the end plate to form a generally conical capture basket. The filter of claim 1 , wherein a subset of the absorbent capture elements are selected to degrade sequentially over time to avoid simultaneous mass release of the capture elements in the blood vessel over time. 2. The tube according to claim 1, wherein the generally round tube is polydioxanone, polytrimethylene carbonate, polyglactin, polyglycolic acid, poly L lactic acid, polyglecapron, polygliton and polylacticoglycolic acid. A filter made from an absorbent material selected from the group consisting of. The filter of claim 1 , wherein the annular element comprises an anchor element or barb for attachment to a blood vessel. The filter of claim 1 , wherein the annular element and/or the capture element comprises a bioactive surface for anticoagulation. an absorbent annular element for attaching or anchoring the filter to a blood vessel; and
An absorbent filter comprising a plurality of absorbent trapping elements attached to said annular element for trapping or inhibiting material flowing in a blood vessel for a limited period of time, said annular element being cut from a generally circular tube of absorbent material. The filter of claim 11 , wherein the plurality of absorbent capture elements are made of absorbent filaments or sutures. 13. The filter of claim 12, wherein a plurality of absorbent capture elements are connected with adjacent absorbent capture elements to establish a capture basket. 14. The filter of claim 13, wherein the plurality of absorbent capture elements are routed to the endplate to form a generally conical capture basket. 12. The method of claim 11, wherein the generally circular tube and absorbent capture element are polydioxanone, polytrimethylene carbonate, polyglactin, polyglycolic acid, poly L lactic acid, polyglecapron, polygliton and poly A filter made from an absorbent material selected from the group consisting of lacticoglycolic acid. The filter of claim 11 , wherein the annular element comprises an anchor element or barb for attachment to a blood vessel. The filter of claim 1 , wherein the annular element and/or the capture element comprises a bioactive surface for anticoagulation. 12. A method of delivering a filter as claimed in any one of claims 1 and 11 with a delivery catheter, the method comprising:
inserting the compressed filter into a desired location within the blood vessel within the delivery catheter; and
disposing the filter in an expanded form at a desired position within the blood vessel; and
subsequently removing the delivery catheter from the blood vessel.

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