absorbable filter

专利摘要:
ABSORBIBLE VASCULAR FILTER. The present invention relates to an absorbable vascular filter for placement within a vessel for the temporary filtration of body fluids. The preferred embodiment is an arrangement of said absorbable vascular filter within the inferior vena cava (IVC) to filter emboli for the prevention of pulmonary embolism for a limited time. Once PE protection is complete, the filter is biodegraded according to a planned program determined by the absorption properties of the filter components. Thus, the temporary absorbable vascular filter avoids the long-term complications of permanent IVC filters such as increased deep vein thrombosis, puncture of neighboring organs due to filter fracture and embolization, while also avoiding the need to remove metal IVC filters. recoverable.
公开号:BR112013021716B1
申请号:R112013021716-2
申请日:2012-02-23
公开日:2021-01-26
发明作者:Mitchell D. Eggers
申请人:Adient Medical, Inc.；
IPC主号:

专利说明:

[0001] [001] The present application claims the priority benefit of US Patent Application Serial No. 13 / 036,351 entitled "Absorbable Vascular Filter" to Mitchell Eggers, electronically filed on February 28, 2011, and US Patent Application No. serial number 13 / 096,049 entitled "Vascular Filter Stent" for Mitchell Eggers, electronically deposited on April 28, 2011, both of which are incorporated herein by reference in their entirety. Field of the Invention
[0002] [002] The present invention relates in general to a vascular filter and more particularly to an absorbable vascular filter disposed within a vessel for the temporary filtration of body fluids. A preferred embodiment is the arrangement of said absorbable vascular filter within the inferior vena cava (CVI) for the prevention of pulmonary embolism for a specific duration of time determined by the absorption properties of the filter. Background of the Invention
[0003] [003] Between about 100,000 to 300,000 Americans die each year from pulmonary embolism (PE) - more than breast cancer and AIDS combined - representing the 3rd leading cause of death in the US [1-5]. A similar incidence of PE is found in Europe with approximately 370,000 deaths annually [6]. Furthermore, PE is the 3rd most common cause of death in trauma patients who survived the first 24 hours. An estimated 25% of all hospitalized patients have some form of deep vein thrombosis (DVT) that is often not clinically apparent unless PE develops [7]. On average, 33% of DVT will progress to symptomatic PE of which 10% will be fatal [6].
[0004] [004] The US Surgeon General recognized this alarming statistic and in 2008 issued a formal call for action to prevent DVT and PE [1]. Unfortunately, DVT / PE disproportionately affects the elderly, in part because of prolonged periods of inactivity following medical treatment. The incidence is relatively low at the age of 50 (1 / 100,000), so it accelerates exponentially reaching 1000 / 100,000 by the age of 85 [8]. Consequently, the US Surgeon General has proclaimed that the growth in the number of DVT / PE cases with the aging of the US population may exceed the population growth in the absence of better prevention [1].
[0005] [005] Risk factors for PE that arose from DVT follow Virchow's Triad [9]: (i) endothelial damage, (ii) hypercoaguability, and (iii) hemodynamic changes (stasis or turbulence). Thus, specific risk factors include hip and knee arthroplasty, abdominal, pelvic and extremity surgery, pelvic and long bone fractures, prolonged immobility such as prolonged hospital stays and air travel, paralysis, old age, previous DVT, cancer, obesity, COPD, diabetes and CHF. Orthopedic surgeons are especially concerned since their patients have a 40% - 80% risk of DVT and PE following knee and hip surgery in the absence of prophylactic treatment [10-12].
[0006] [006] The American Academy of Orthopedic Surgeons (AAOS) has issued guidelines for PE prophylaxis. Basically, patients at standard risk should be considered for chemoprophylactic agents such as aspirin, low molecular weight heparin (LMWH), synthetic pentasaccharides, or Warfarin a, in addition to immediate and / or intraoperative postoperative mechanical prophylaxis [13].
[0007] [007] Aspirin has a 29% reduction in the relative risk in symptomatic DVT and a 58% reduction in the relative risk in fatal PE [14]. LMWH has a 30% risk reduction in DVT and has proven to be more effective than unfractionated heparin in high-risk groups such as hip and knee arthroplasty [7]. Warfarin started within 24 to 48 hours from the start of heparin with the aim of achieving the international normalized relationship (INR) results between 2 and 3 as secondary thromboprophylaxis for 3 months reduces the risk of recurrent venous thromboembolism (VTE) by 90% ) compared to placebo [15,16]. Mechanical prophylaxis, which consists of pneumatic compression devices that repeatedly compress the legs with an air bladder, are also used in conjunction with anticoagulants to reduce the occurrence of PE.
[0008] [008] The duration of prophylaxis depends on the potential source of DVT. Current prophylaxis recommendations consist of a minimum of 7-10 days for moderate to high risk surgeries and up to 28-35 days for many orthopedic surgeries. Specifically for orthopedic trauma, DVT prophylaxis is continued until the patient's immobilization (32%), hospital discharge (19%), 3 weeks postoperatively (16%>), 6 weeks postoperatively (27 %>), and in rare circumstances longer than 6 weeks (7%) [17]. Studies have indicated that hypercoaguability persists for at least one month after damage in 80% of trauma patients [18]. With regard to knee and total hip arthroplasty and cancer surgery, 35 days of prophylactic treatment is recommended [12, 19]. In general, prophylactic treatment for possible VTE is often guaranteed for up to 6 weeks after trauma or major surgery.
[0009] [009] Contraindications for chemoprophylaxis include active bleeding, hemorrhagic diathesis, hemorrhagic attack, neurological surgery, excessive trauma, hemothorax, pelvic or lower extremity fractures with intracranial bleeding, anticoagulant interruption, and recent DVT / PE patients who will undergo surgery .
[0010] [0010] For patients who are contraindicated for the above mentioned anticoagulant prophylaxis, or where anticoagulant therapy has failed, AAOS, American College of Physicians, and the British Committee of Standards in Haematology all recommended the use of inferior vena cava filters (IVC) [13, 20, 21]. Said intravascular metal filters are disposed by means of a catheter inside the CVI to essentially capture emboli that arise from DVT before reaching the lungs resulting in PE. In addition, the British Committee of Standards in Hematology recommends the provision of an IVC filter in pregnant patients who have contraindications to anticoagulants and who develop extensive VTE just before delivery (within 2 weeks).
[0011] [0011] The Eastern Association for Surgery of Trauma additionally recommends prophylactic IVC filters arranged on trauma patients who are at high risk for bleeding and prolonged immobilization [22]. These prophylactic recommendations follow studies that demonstrate a low PE coefficient in patients with severe polytrauma who have undergone IVC placement [23-25]. In fact, the indication of faster growth in the general use of IVC filters, from 49,000 in 1999 to 167,000 in 2007 with a projection of 259,000 units for 2012, is the prophylactic market using recoverable IVC filters [26, 27].
[0012] [0012] Examples of vascular filters mainly for IVC placement are described in US Patent No. 4,425,908; US Patent No. 4,655,771, US Patent 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 No. 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. 2007/01 12372 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] [0013] The effectiveness of the IVC filter has been demonstrated in several studies of evidence of classes I and II [22, 28-30]. Most of the previous filters installed were expected to be permanent fixations since endothelization occurs within 7-10 days making most models impractical to remove without irreversible vascular damage leading to life-threatening bleeding, CVI dissection, and thrombosis. Although these permanent filters have avoided PE, they have actually been shown to increase the risk of recurrent DVT over time.
[0014] [0014] Specifically, the Cochrane review [31] on the use of IVC filters for the prevention of PE cites a level I randomized prospective clinical test by Decousus et al. [32] in which the incidence of DVT with the IVC filter group increased almost 2-fold: (i) 21% incidence of recurrent DVT in the filter group compared to 12% in the LMWH non-filter group in 2 years (p = 0.02), and (ii) 36% incidence of recurrent DVT in the filter group compared to 15% in the 8-year old group without filter (p = 0.042) [33]. However, the filters reduced the occurrence of PE; the filter group experiencing only 1% PE compared to the non-filter group 5% PE in the first 12 days (p = 0.03). No statistically significant difference in the mortality rate was observed at any time frame investigated. Apparently the initial benefit of reduced PE with permanent IVC filters is offset by an increase in DVT, without any difference in mortality.
[0015] [0015] In addition to increasing the incidence of DVT for placing a prolonged CVI filter, filter occlusion has been reported with an occurrence of 6% to 30%, as well as filter migration (3% to 69%), venous insufficiency (5% 59%), and post-thrombotic syndrome (13% to 41%) [34-36]. Complications from insertion include hematoma, infection, pneumothorax, vocal cord paralysis, attack, air embolism, poor placement, inclined arteriovenous fistula, and inadvertent carotid artery puncture has an occurrence rate of 4% - 11% [37 ].
[0016] [0016] Temporary or recoverable IVC filters have been marketed more recently with the intention of being removed once the risk of PE decreases, and thus avoid the many deleterious complications of permanent filters. Recoverable filters feature flexible hooks, collapsible components, and unrestricted legs to facilitate removal. Unfortunately, these same characteristics led to an unwanted migration of the filter, failure due to fatigue, penetration of the CVI, migration of fragments to the hepatic veins and pulmonary arteries, inclination of the filter, metallic emboli [38-43]. Since 2005, 921 adverse filter events have been reported to the FDA and include 328 device migrations, 146 device detachments (metallic pistons), 70 CVI perforations, and 56 filter fractures [44]. Some brands of recoverable filters have posted alarming failure rates such as the Bard Recovery filter with 25% fracture in 50 months which has embolized the final organs. 71% of the fractures that embolized the heart caused life-threatening ventricular tachycardia, tamponade, and sudden death in some cases. An alternative recoverable model, Bard G2, resulted in 12% fractures in 24 months [45]. The referred prevalence of device fractures is postulated to be directly proportional to the length of stay.
[0017] [0017] These and other shortcomings caused the FDA in August 2010 to issue a formal communication stating that the "FDA recommends that physicians and clinicians responsible for the care of patients with recoverable IVC filters consider removing the filter as soon as PE protection. is no longer needed "[44]. Although these types of recoverable filters are intended to be removed over a period of months, several studies indicate that approximately 70% -81% of patients with recoverable IVC filters fail to return to the hospital to remove the filter, thereby exposing hundreds of thousands of people. patients to life-damaging adverse events by prolonged placement of a recoverable IVC filter [41, 44, 46-48]. These patients are somehow lost in relation to the follow-up of the disease, or refuse to have the filters removed in the absence of complications. Brief Summary of the Invention
[0018] [0018] The present invention comprises systems and methods for filtering fluids. Certain modalities include a new absorbable vascular filter that temporarily prevents pulmonary embolism by capturing and retaining emboli within a vessel in the body. The absorbable vascular filter, according to certain aspects of the present invention, has several advantages over all conventional vascular filters, including permanent, temporary, and optional IVC filters. Most importantly, the absorbable vascular filter described here is slowly biodegraded within the vessel according to a planned program designed by choosing the absorbable filter materials that avoid the need to remove the filter.
[0019] [0019] In addition, the elements of the absorbable vascular filter are manufactured from synthetic non-metallic polymers that do not adversely impact the final organs with a carefully planned degradation as shown by conventional metal IVC filters that migrate and often become fractionated. Also due to the relatively short residence time (months) of the absorbable vascular filter, the paradoxical increase in DVT seen with conventional long-term IVC filters is likely to be avoided. Brief Description of Drawings
[0020] [0020] Figure 1a is a sectional isometric view of an embodiment of the absorbable vascular filter that includes sequentially phased biodegradation of the absorbable capture elements.
[0021] [0021] Figure 1b characterizes the capture elements of figure 1a in detail.
[0022] [0022] Figure 1c characterizes the capture elements of figure 1b at a later point in time when the proximal portion of the capture elements was bioabsorbed / biodegraded.
[0023] [0023] Figure 1d characterizes the capture elements of figure 1c at a later point in time when the middle and proximal sections of the capture elements were bioabsorbed / biodegraded, leaving only the distal section.
[0024] [0024] Figure 1e represents the complete bioabsorption / biodegradation of the capture elements of figure 1b at the most distant point in time.
[0025] [0025] Figure 2a is a cross-sectional scheme of another modality of the absorbable vascular filter that also characterizes the sequential phased biodegradation of the absorbable capture elements.
[0026] [0026] Figure 2b is an enlarged end view of the absorbable capture elements of the absorbable filter shown in figure 2a.
[0027] [0027] Figure 2c illustrates the capture elements of figure 2b when installing the filter in a vessel.
[0028] [0028] Figure 2d illustrates the capture elements of figure 2c at a later point in time when the inner capture ring element was bioabsorbed / biodegraded.
[0029] [0029] Figure 2e illustrates the capture elements of figure 2d at a later point in time when a circumferential mounted capture element was bioabsorbed / biodegraded.
[0030] [0030] Figure 2f illustrates the capture elements of figure 2e at a later point in time when two circumferential mounted capture elements were bioabsorbed / biodegraded.
[0031] [0031] Figure 2g illustrates the capture elements of figure 2f at a later point in time when only one circumferentially mounted capture element remains after bioabsorption / biodegradation.
[0032] [0032] Figure 2h illustrates the capture elements of figure 2b that have been completely bioabsorbed / biodegraded at the furthest point in time.
[0033] [0033] Figure 3a is a sectional isometric view of a vascular filter modality that includes a plurality of capture elements attached to the stent to filter substances such as plungers.
[0034] [0034] Figure 3b characterizes the capture elements of figure 3a in detail.
[0035] [0035] Figure 4a is an absorbable vascular filter constructed from 3-0, 2-0, 0, and 1 polydioxanone sutures in an interlaced pattern that characterizes sequential degradation based on varying diameters and expiration dates capture elements.
[0036] [0036] Figure 4b is an absorbable vascular filter constructed from a similar polydioxanone suture in a woven pattern design in figure 4a except that only size 2-0 is used.
[0037] [0037] Figure 4c is an absorbable vascular filter constructed from a 2-0 size polydioxanone suture in a radial pattern typical of traditional IV filters.
[0038] [0038] Figure 4d is an absorbable vascular filter constructed from a 3-0, 2-0, 0, and 1 polydioxanone suture in a radial pattern that characterizes sequential degradation based on varying diameters of the capture elements.
[0039] [0039] Figure 5 shows photographs of the absorbable filter shown in figure 4a during in vitro testing in weeks 0, 7, 13-22 to reveal the sequential degradation of the filter losing 1 to 2 capture elements per week starting at week 13 and reaching the final disintegration by week 22.
[0040] [0040] Figure 6 is a graph of the average burst load (kg / filament) of polydioxanone capture elements in relation to time during the in vitro test.
[0041] [0041] Figure 7 is a graph of the resistance retention of the polydioxanone capture element as a percentage of the original resistance over time.
[0042] [0042] Figure 8 is a graph of Young's modulus for polydioxanone capture elements in relation to time during in vitro testing.
[0043] [0043] Figure 9a is a cross-sectional diagram showing a preferred method for installing the absorbable vascular filter using a catheter-based system with the filter in compressed mode.
[0044] [0044] Figure 9b is a schematic cross-section detailing the placement of the absorbable vascular filter using a catheter-based system with a sliding outer sheath to position the filter in fully expanded mode.
[0045] [0045] Figure 9c is a cross-sectional schematic detailing the removal of the central stabilizing rod or piston used to stabilize the absorbable vascular filter while removing the outer sheath from the catheter-based installation system.
[0046] [0046] Figure 9d illustrates the operation of the absorbable vascular filter in the presence of a plunger in the vessel.
[0047] [0047] Figure 9e represents the vessel after the complete biodegradation / bioabsorption of the absorbable vascular filter.
[0048] [0048] Figure 10a represents a modality of the absorbable vascular filter constructed from a braided stent or tissue integrated with a capture basket.
[0049] [0049] Figure 10b is the associated top view of the absorbable vascular filter shown in figure 10a.
[0050] [0050] Figure 11 is an expanded view of the braiding or weaving of absorbable elements comprising the stent section of the absorbable vascular filter.
[0051] [0051] Figure 12 is an expanded view of the braiding or weaving of the absorbable elements comprising not only the stent section but also the capture basket for the integrated absorbable vascular filter.
[0052] [0052] Figure 13a is a photograph of an integrated absorbable IVC filter woven with a single synthetic filament.
[0053] [0053] Figure 13b is an end view photograph of the integrated absorbable IVC filter shown in figure 13a. Detailed Description of the Invention
[0054] [0054] Modalities of the present invention will now be described in detail with reference to the drawings and photos, which are provided as illustrative examples in order to allow those skilled in the art to practice the present invention. Notably, the figures and examples below are not intended to limit the scope of the present invention to a single modality, but other modalities are possible through the exchange of some or all of the elements described or illustrated. Whenever convenient, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. Where certain elements of said modalities can be partially or completely implemented using known components, only those portions of said known components that are necessary for an understanding of the present invention will be described, and detailed descriptions of other portions of said known components will be omitted so as to not to obscure the present invention. In the present report, a modality showing a singular component should not be considered as limiting; instead, the present invention is intended to encompass other embodiments that include a plurality of the same component, and vice versa, unless explicitly stated otherwise here. Furthermore, claimants do not intend for any term in the specification or claims to be related to an unusual or special meaning unless explicitly stated here as such. In addition, the present invention encompasses the present and future equivalents known to the components referred to herein as an illustration.
[0055] [0055] With reference to the embodiment illustrated in figures 1a-e, an absorbable vascular filter 1 consists of an external circumferential element 2 to support a plurality of absorbable filter capture elements (30 - 32, 40 - 41). The capture elements are purposely designed to be biologically absorbed and / or degraded preferably in a sequential manner to avoid simultaneous detachment of the entire filter causing an unexpected plunger. Sequential degradation can be controlled by choosing absorbable polymers that have different absorption profiles, diameter, and / or expiration dates. In addition, absorption bonds can be incorporated to serve as detachment points during absorption. Sequential bioabsorption / biodegradation is illustrated in the figures, 1b-e where the decomposition starts with the proximal capture elements 30, progressing to the capture elements of the middle section 31, and finally the complete bioabsorption / biodegradation as illustrated in figure 1e.
[0056] [0056] The said sequential projected bioabsorption / biodegradation of the capture elements can be achieved with numerous synthetic materials. The goal is to select the absorbable filter materials to match a desired filter life. From the background section, a filter stay of 6 weeks would be suitable for an IVC filter to prevent PE after trauma or in conjunction with major surgery. Synthetic materials that can be used to form the capture elements include:
[0057] [0057] Polydioxanone (PDO, PDS) - colorless, crystalline biodegradable synthetic polymer with multiple ether-ester repeat units. In suture form, PDS II (Ethicon, Somerville, NJ) size 4/0 and smaller maintains 60%, 40%, and 35% of its resistance to tension in 2, 4, and 6 weeks respectively. For PDS II size 3/0 and larger, it retains 80%, 70%, and 60% of its tensile strength in 2, 4, and 6 weeks respectively. In addition to providing support to the lesion for 6 weeks, PDS II suture is completely absorbed in 183-238 days through hydrolysis making it a strong candidate for IVC filter applications. Basically, absorption is minimal in the first 90 days and is essentially complete in 6 months. Finally, PDS has low affinity for microorganisms and has minimal tissue reaction.
[0058] [0058] Poly-trimethylene carbonate (Maxon) - similar to the PDS in absorption profile and still with relatively greater resistance to rupture. Maxon (Covidien, Mansfield, MA) maintains 81%, 59%, and 30%) of its tensile strength in 2, 4, and 6 weeks respectively, and is completely hydrolyzed in 180-210 days.
[0059] [0059] Polyglactin 910 (Vicryl) - braided multifilament coated with a lactide and glycolide copolymer (Polyglactin 370). As a suture, Vicryl (Ethicon) size 6/0 and larger maintains 75%, 50%>, and 25% of its resistance to tension in 2, 3, and 4 weeks respectively and is completely absorbed in 56-70 days.
[0060] [0060] Polyglycolic acid (Dexon) - similar to Polyglactin, produced from polyglycolic acid and coated with polycaprolate. Dexon has a similar profile of resistance to tension and absorption as polyglactin.
[0061] [0061] Polyglecaprone 25 (Monocryl) - synthetic copolymer of glycolide and e-caprolactone. Monocryl (Ethicon) maintains 50% -70% and 20% -40% of its resistance to tension in 1 and 2 weeks respectively and is completely absorbed in 91-119 days.
[0062] [0062] Copolymer of polylacticoglycolic acid (PLGA) of monomers glycolic acid and lactic acid. Different forms and properties of PLGA can be manufactured by controlling the ratio of lactide to glycolide for polymerization. As with other synthetic absorbable materials, PLGA degrades by hydrolysis with the absorption profile dependent on the monomer ratio; the higher the glycolide content, the faster the degradation. However, a 50:50 copolymer exhibits the fastest degradation in 2 months. Since the polymer degrades in the body to produce lactic acid and glycolic acid, both being normal physiological substances, PLGA proposes minimal systemic toxicity.
[0063] [0063] Poly L-lactic acid (PLA) is also a polymer produced from lactic acid still with considerable longevity. In soft tissue approach, PLA remains intact for 28 weeks, and is completely absorbed within 52 weeks.
[0064] [0064] As an example of the design of the capture elements to sequentially degrade after the PE protection period, the proximal capture elements 30, 41 can be manufactured with PDS II size 4/0 (0.15 mm in diameter) , while the intermediate capture elements 31, 40 manufactured with size 2/0 (0.3 mm in diameter), and finally the distal capture elements 32 manufactured with size 2 (0.5 mm) of PDS II suture.
[0065] [0065] As an alternative to assemble a plurality of capture elements, the vascular filter can be manufactured with an absorbable or non-absorbable composite mesh. Candidates for a mesh capture system include polypropylene such as C-QUR (Atrium Medical Corp. Hudson NH), polypropylene encapsulated polypropylene as in PROCEED (Ethicon, Somerville, NJ), polypropylene co-knit with polyglycolic acid fibers as in Bard Sepramesh IP Composite (Davol, Inc., Warwick, RI), polyethylene terephthalate as in Parietiex Composite (Covidien, Mansfield, MA), and ePTFE used in DUALAMESH (W. Gore & Assoc. Inc., Flagstaff, AZ).
[0066] [0066] With reference to the circumferential element 2 in figures 1, 2, and 3 that serve to support the capture elements of the absorbable vascular filter and maintain positioning of the filter inside the vessel with the expansion from a catheter, be it an absorbable material as described above or non-absorbable material can be used. A non-absorbable material would essentially serve as a permanent stent, lasting well beyond the life of the absorbable capture elements. This can be an important option in cases where the vessel needs help to maintain patency. Both types of circumferential elements 2 can incorporate barbs 79 (with reference to figure 2) to maintain the positioning of the filter with the placement. Plausible non-absorbable materials for the construction of the circumferential element include: Nitinol, Elgiloy, Phynox, 316 stainless steel, MP35N alloy, titanium alloy, platinum alloy, niobium alloys, cobalt alloys, and tantalum wire.
[0067] [0067] Figures 2a-2h illustrate another modality of the absorbable vascular filter in which the absorbable capture elements 60-64 are mounted to a simple circumferential element 2 held against the wall of the vessel 70 with optional splinters 79. Here again the circumferential element 2 can be made from absorbable or non-absorbable materials such as those described above. An enlarged cross-sectional view of the capture element assembly 65 is shown in figure 2b. It is observed that the sequential degradation of the capture elements is achieved by varying the diameter of the chosen absorbable material. For example, the internal capture element 60 can be PDS II 4/0 (0.15 mm in diameter) resulting in faster absorption as shown in figure 2d at time tls followed by capture element 61 the degradation being PDS II 3 / 0 (0.20 mm in diameter) at time t2 in figure 2e, followed by capture element 62, the degradation being PDS II 2/0 (0.30 mm in diameter) at time t3 in figure 2f, followed by the element of capture captures 63 the degradation being PDS II 0 (0.35 mm in diameter) at time t4 in figure 2g, and finally the degradation of the last capture element 64 constructed of PDS II 1 (0.40 mm in diameter) at time ts in figure 2h. Although the said dimensions represent a specific example, any diameters within approximately 0.1 mm to 0.7 mm will be sufficient. In general, a gradual progression of degradation is purposefully projected following a 6-week prophylactic window for trauma and major surgery applications.
[0068] [0068] With reference to the modality illustrated in figures 3a and b, a vascular filter 1 consists of an external circumferential stent 2 to support a plurality of collapsible filter capture elements (60 - 64) and to maintain the patency of the vessel. The capture elements are purposely designed to be collapsible for catheter-based installation and to prevent damage to the final organ. The support stent 2 is shown to be manufactured as an artificial vascular graft supported by corrugated support structures 3. Said vascular filter, which can be comprised of absorbable or non-absorbable filter capture elements, have several advantages over all conventional vascular filters, include permanent, temporary, and optional IVC filters. Most importantly, the vascular filter is manufactured with the stent that serves as a circumferential assembly for the capture elements in addition to providing patency of the vessel, and avoids the endothelialization characteristic of metal filters with barbed supports. Thus, the increased incidence of DVT observed with metal IVC filters due to the inherent damage to the vessel by the metal supports is probably avoided.
[0069] [0069] The circumferential stent element 2 in figure 3a serves to support the capture elements of the vascular filter, in addition to maintaining the patency of the vessel and maintaining the stationary positioning of the filter within the vessel with the expansion. Numerous types of stents used conventionally as thoracic endoprostheses can be used. Such stents include Gore TAG, Medtronic Talent and Valiant Systems, and Cook Zenith TX2 System. In particular, Gore TAG is comprised of an artificial vascular graft manufactured with a fluoropolymer (expanded polytetrafluoroethylene PTFE and fluorinated ethylene propylene or FEP) combined with a Nitinol support structure. Alternatively, the stent's vascular filter component can be manufactured only with the support structure (without the artificial vascular graft) using a nickel-titanium alloy (Nitinol), cobalt-chromium-nickel alloy (Elgiloy), cobalt alloy -chromium-nickel-molybdenum (Phynox), 316 stainless steel, MP35N alloy, titanium alloy, platinum alloy, niobium alloys, cobalt alloys, and tantalum wire.
[0070] [0070] A specific modality of an absorbable vascular filter with sequential degradation was constructed, tested, and evaluated with assorted polydioxanone sutures (sizes 3-0, 2-0, 0, and 1) and is shown in figure 4a. The filter featured higher tissue density than shown in figure 2b to capture smaller plungers. Polydioxanone was the preferred candidate polymer based on stress retention and absorption properties proven in injury approach applications. Tygon long flex lifetime tubes (Saint-Gobain Performance Plastics, Akron, OH) with 25.4 mm id similar to the IVC were used for the vessel wall in which the polydioxanone was manufactured in various filter patterns shown.
[0071] [0071] Figure 4a shows capture elements with interlaced pattern that are purposely designed for sequential or phased absorption to avoid simultaneous detachment of the entire filter during absorption. Here polydioxanone filaments of varying diameters (size 3-0, 2-0, 0 and 1) were used to vary the time for complete absorption, in addition to varying the expiration dates. Since absorbable polymers initially break at stress points during absorption, the interlaced pattern filters were designed to disintegrate into 8 pieces along length D / 2, and 8 pieces of size D / 4, where D is the inner diameter of the vessel. The objective is the gradual, phased or sequential disintegration, to minimize the free floating exposure of the capture elements of the polymer filter in the circulation. Figure 4b is the same interlaced pattern design but uniformly sized for polydioxanone suture for comparison. Figure 4c is a radial filter design similar to conventional metal IVC filters and still shows sutures of variable diameter for sequential absorption. Finally, figure 4d is a radial design constructed exclusively with size 2-0 polydioxanone.
[0072] [0072] The main end point for the evaluation of absorbable polymers for application in a vascular filter was burst load as a function of time. In addition to the absorbable filters illustrated in Figure 4, several test cells were manufactured with the various absorbable polymer candidates for weekly destructive stress testing. The polymer characterization was carried out using the ADMET eXpert 7601 stress test machine with the MTESTQuattro program (Norwood, MA) at weekly intervals to produce tension in relation to the stress graphs beyond the main end point of the breaking load, and several points secondary endings: (i) maximum tension (resistance to tension), (ii) maximum effort (% of elongation at break), (iii) energy at break, and (iv) Young's modulus of elasticity. The ADMET machine was operated at a crosshead speed of 3 cm / min and equipped with a 1001b high-resolution load cell and 2KN pneumatic fasteners.
[0073] [0073] The candidate absorbable polymers (representing the capture elements) sewn into the test cells were embedded in a closed circulation system designed to mimic human cardiac physiology. At weekly intervals, the system was closed to extract the sutures of each size and type to perform a destructive stress test. As a control, identical absorbable sutures were submerged in a static buffer bath (StableTemp digital utility bath, Cole-Parmer, Vernon Hill, IL) maintained at 37 ° C and also tested on a weekly basis. The hypothesis being that the greater thermodynamics of the circulation system accelerates not only the absorption coefficient but also the loss of resistance to tension of the capture elements.
[0074] [0074] The closed circulation system was constructed with de "thin-walled PVC with od 26.7 mm that fit tightly inside the flexible tube 25.4 mm id Tygon that simulated the CVI. The heart of the system was a pressure pump Harvard Apparatus large animal pulsatile blood (Holliston, MA) that simulated the ventricular action of the heart.The Harvard Apparatus blood pump was operated almost continuously for 22 weeks (913K L pumped) with less preventive maintenance.
[0075] [0075] Heart rate was adjusted to 60 bpm, stroke volume between 60 and 70 mL, systolic / diastolic duration coefficient 35% / 65%, and systolic blood pressure varied from 120 mmHg (conditions simulated for an arterial filter for avoid cerebral and systemic embolism) at 5 mmHg (simulated conditions for an IVC filter to prevent PE).
[0076] [0076] Real-time measurements were available from the upstream and downstream sensor tubes. Upstream sensors from the absorbable filters under test included digital temperature, flow coefficient (L / min), total flow (L), and pressure (mmHg). The downstream instrumentation included real-time measurement of% oxygen, total dissolved solids (TDS in ppt), and pH. TDS monitoring was included to assess absorption by-products less than 20 microns in size, while the 80 micron downstream in-line filter would capture suture fragments from the filters and test cells.
[0077] [0077] The 4 candidates of absorbable vascular filters introduced in figure 4 were installed in series along the upstream tubes, while 5 test cells containing absorbable suture for destructive testing on a weekly basis were installed in series along the downstream section of the in-vitro cardio test system. A heating tape A 288W with thermostat was used to maintain 37 ° C inside the closed circulation system. Finally, the circulation fluid was pH 7.4 phosphate buffer (Invitrogen, Carlsbad, CA) with an electrolyte profile similar to that of human blood. Buffer was replaced weekly in an effort to keep the pH stable.
[0078] [0078] The absorption and stress properties of the selected polymers were determined as a function of the time until the degradation resistance in both the circulation system and the control bath is completed. The phosphate buffer in the circulation system was changed weekly as the pH decreased from 7.4 to a measurement of 6.6 during each week. The buffer was changed in the control bath only monthly due to the better pH stability in the static environment. The average flow was 4.7 L / min while the average oxygen was 30% and TDS 8.8 ppt.
[0079] [0079] The phase absorption or sequential absorption of the interlaced pattern absorbable filter is illustrated in the collage of figure 5. It is observed that the filter begins to disintegrate during the 13th week and continues in a phased mode, losing only 1 or 2 catch elements per week thereafter, until complete disintegration in 22 weeks. The initial fractures detected at the 13th week were located at points of high tension within the capture elements. Since the apex of a capture element mounted to the circumferential support experiences twice the tension compared to the base of the capture element, the initial break will be at the apex. The capture elements that formed loops that extend from the vessel wall to the center of the filter were constructed of polydioxanone size 1 and 0 with an expiration date of January 2012, while the shorter capture elements that extended to a quarter of the diameter were constructed with 3-0 polydioxanone suture size with an expiration date of January 2015. The expiration date was observed to play a more important role than the suture diameter in the absorption coefficient since the suture of smaller diameter broke at week 17, versus the larger diameter suture that broke at week 13. The planned disintegration of 8 elements of length D / 2 and 8 elements of length D / 4 for the interlaced pattern filter actually produced less fragments brittle due to splinters and fragmentation. In fact, the largest filter element captured from the pattern design intertwined by the 80 µm downstream filter revealed a maximum fragment size of 5 mm x 0.3 mm.
[0080] [0080] Perhaps the superior feature under consideration for use in an absorbable vascular filter is the retention resistance profile of absorbable polymers as illustrated in figure 6 for polydioxanone in the in vitro circulation system. As shown, polydioxanone initially exhibits moderate resistance to degradation, less than approximately 5% per week for the initial 5 to 6 weeks, followed by the rapid decline approaching 20% per week thereafter. As a conservative summary of the initial 5 weeks in circulation, size 1 polydioxanone maintained about 10 kg of resistance, size 0 maintained 6 kg, size 2-0 maintained 4 kg, and size 4-0 maintained 1.5 kg. Similar results were obtained from a buffer control bath for the initial 5 weeks.
[0081] [0081] However, the statistical difference was reached at week 5 for size 0 (p <0.014), week 6 for sizes 2-0 and 1 (p <0.021), and week 7: p <0.011).
[0082] [0082] The proposed filter designs employed multiple filaments serving as capture elements, since the piston charge is distributed across N filaments. Therefore, assuming an equal distribution, the net piston load that can be accommodated by the filter is a multiple, N, of the load per rupture filament. Consequently, the polydioxanone size 2-0 filter with 8 capture elements attached to the circumferential support would accommodate a net piston load of 32 kg.
[0083] [0083] An alternative method for assessing the retention strength for polymers is to represent the percentage of retention strength as a function of time as shown in figure 7. Here all sizes of polydioxanone slowly lost strength in the first 5 weeks, then quickly absorbed to a negligible resistance by the 10th week. Specifically, polydioxanone within the in vitro circulation system retained an average resistance for sizes 2-0 and greater than 88% in 2 weeks, 85% in 4 weeks, and 68% in 6 weeks compared to in-tissue approximation applications. live from Ethicon that produced 80% in 2 weeks, 70% in 4 weeks and 60%> in 6 weeks by the Ethicon product literature.
[0084] [0084] Young's modulus of elasticity varied from 1.0 - 2.3 GPa for polydioxanone as shown in figure 8 for absorbable filter elements. It is observed that Young's modulus initially reduced (polymer became more elastic) as it was submitted to the buffer, reached a minimum in 6 weeks, then increased to approximately twice the initial value. This increase in Young's modulus for polydioxanone is indicative of the greater fragility as it reached the terminal zero resistance, and was additionally observed during disintegration. This property can be quite advantageous for the application in absorbable filter. For example, as the polydioxanone reached zero terminal resistance and disintegrated, it shattered and broke into smaller fragments, thus being brittle potentially less harmful to the downstream organs. Additionally, studies are needed to determine the exact size of the fragments in vivo and to evaluate the potential of pulmonary micro infarctions.
[0085] [0085] The conclusion from the in vitro absorbable filter study, polydioxanone appears to be a strong candidate for absorbable vascular filters with sufficient retention resistance to capture plungers for at least 6 weeks, then absorb quickly in the next 16 weeks via hydrolysis into carbon dioxide and water. Specifically, size 2-0 polydioxanone has been shown to maintain a conservative 4 kg load breaking per filament for 5 weeks in circulation. Thus, a filter incorporating 8 capture elements would capture a piston load of 32 kg; or equivalent, an embolism would have to send 1600 kg mm of energy to break the filter which is highly unlikely considering that the pressure in the CVI is a mere 5 mmHg (about 0.1 psi).
[0086] [0086] Furthermore, the geometry of the interlaced pattern filter with capture elements of varying diameters and expiration dates has been shown to disintegrate in a sequential or phased mode, releasing 1 or 2 small brittle filter fragments (less than 5 mm x 0.3 mm each) weekly in circulation from weeks 14 to 22. Additionally, polydioxanone is FDA approved and proved to be non-allergenic and non-pyrogenic, a catheter-disposable polydioxanone vascular filter would likely be an effective device and efficient for the prevention of pulmonary embolism.
[0087] [0087] A preferred installation of the absorbable vascular filter is through intravenous insertion with a catheter needing only a local anesthetic as illustrated in the figures. 9a-e. Here the filter is collapsed and compressed into a delivery catheter comprised of an outer sheath 71 and an internal applicator piston or stabilizer 73 on a central rod as illustrated in figure 9a. For placement of the IVC filter, the sending catheter is inserted into the patient's vasculature in a convenient location, such as the femoral or internal jugular vein. Subsequently, the sending catheter is fed through the vasculature typically over a guidewire until it reaches the desired placement site, less frequently than the renal veins. Then the compressed filter 50 is allowed to expand by sliding the outer sheath 71 in the proximal direction while simultaneously pushing the stabilizing rod and piston 72 in the distal direction (with reference to figure 9b). Since the outer sheath 71 is removed away from the filter, the stabilizing piston 73 can also be retracted as shown in figure 9c. Consequently, to the extent that a thrombosis event releases a plunger 80, the plunger is captured by the vascular filter and is prevented from traveling to the heart and lungs thereby avoiding a potentially fatal PE (with reference to figure 9d). Following the desired prophylactic time window for using the filter (approximately 6 weeks in many applications), the filter is biologically absorbed resulting in the absence of any foreign material in the vessel as illustrated in figure 9e.
[0088] [0088] An alternative embodiment of the absorbable vascular filter 1 is illustrated in figure 10a with an integrated circumferential support 102 and capture basket 101. Here circumferential support 102 and capture basket 101 are braided or woven like a radial expandable stent that it can be compressed into a catheter as described above prior to placement. Figure 10b is a top view of the absorbable vascular filter showing the braiding or weaving of the capture basket 101. The weaving is shown to maintain a patent center 104 to allow insertion of a guidewire during placement of the catheter. The interesting aspect of this particular modality is that the entire absorbable vascular filter (circumferential support and capture basket composed of the capture elements) can be manufactured from a single filament with a radial force designed to prevent the migration of the filter as described below.
[0089] [0089] The integrated absorbable vascular filter shown in the figures. 10a and b produces a diametrically expandable and compressible tubular filter that exhibits a radial force with a magnitude dependent on the chosen materials, angle phi (φ) of the crossed elements of the braiding, and the amount of diameter on the adjustment employed. Specifically, the important angle for establishing the radial force is illustrated as φ in figure 11. The greater the angle φ as it approaches 180 °, the greater the amount of radial force provided by the tissue. Typically φ is an obtuse angle, chosen between 90 and 180 °.
[0090] [0090] For illustration, a simple cylindrical braided weave (L = 7, P = 4) is shown in figure 11 cut in the longitudinal direction and laid flat on a surface revealing the loop pins 110 and the braiding filament 103. Considering the braiding as a series of sinusoidal waveforms of period Ρτ (see the bold section of the weave in figure 11), where P is the number of loop pins traversed for a sinusoid cycle and τ is the pin-to-pin spacing, an algorithm can be derived to ensure that for a given set of parallel loop pins L that equidistantly spread out on the circumference of the intended diameter of the vascular filter, each pin will be looped once and the final loop ending at the origin.
[0091] [0091] The algorithm can be visualized by the table as shown in Table 1 to indicate the relationship between L, P and the angle φ for any desired number of circumferential loops (L).
[0092] [0092] L / P represents the fractional number of sinusoids through the circumference, and N represents the total number of turns around the circumference of the cylinder. Essentially the weave creates sinusoid that is out of phase by a fixed increment until the final loop is reached which the final sinusoid is desired to be in phase with the initial sinusoid. The phase condition requires that the product Nx (L / P) is an integer. In addition, to ensure that all pins are looped, the first integer to be formed by the product Nx (L / P) must occur where N = P.
[0093] [0093] For example, with L = 7 and P = 4, the first integer that appears in the row that corresponds to P = 4 in Table 1 is where N = 4 so that said combination of L, P, and N it will provide a successful braiding in which all the pins will be used (7 through the top, 7 through the bottom) and the final braiding will end at the origin. It can be shown that L must be an odd integer for successful braiding. It can additionally be shown that the angle φ can be expressed as φ = 2tan_1 (P7i; r / Ll) where re 1 is the radius and the length of the desired circumferential support filter 102. The values for r 1 used to calculate φ in Table 1 were 0.625 and 1.5 inches respectively. Also τ is easily computed from the ratio Lx = 2πΓ or τ = 27ir / L.
[0094] [0094] Figure 12 illustrates another combination of braiding where L = 7 and P = 6. It is observed that the first integer to appear in the row for P = 6 in Table 1 corresponds to N = 6 so the braiding will end with success at the origin and all L pins are looped once. Additionally, figure 12 illustrates a method for forming the capture basket 101 as a simple continuous extension of the filament ahead of the circumferential support 102. As shown at the loop points alternating across the top of the circumferential support, the conical capture basket 101 is woven. by loops sequentially interlocked from adjacent loops 105 and extending a loop to the apex 106. The apical loops from each extension 106 can be connected by revealing a conical capture basket as shown in figure 10b with a patent central apex 104. Clearly, other braiding patterns can be used to produce the resolution pattern sufficient to trap the pistons of a desired size.
[0095] [0095] Although only a set of 7 loop pins was considered for simplicity in the illustrations above, a most likely useful number for an absorbable vascular filter for CVI may well be 17 or 19 with φ> 100 °. Specifically, an absorbable IVC filter with integrated circumferential support and capture basket was manufactured with a single synthetic 10ft (0.5mm diameter) filament as shown in the figures. 13a and b with L = 17, P = 16, φ = 102 °, 1 = 1.5 ", r = 0.625", and τ = 0.23 ". The self-expanding IVC filter provides sufficient radial force to maintain the IVC arrangement by choice of the obtuse braiding angle, 25% of oversized diameter (to adapt to the 1 "diameter of IVC), and filament of wide diameter (0.5 mm). Alternatively, the integrated absorbable vascular filter described above can be constructed with multiple connected filaments, although a single continuous filament may be preferable.
[0096] [0096] Although 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 can be made to said embodiments without departing from the broad spirit and scope of the present invention. Therefore, the specification and the drawings must be observed in an illustrative sense instead of in a restrictive sense.

权利要求:
Claims (27)
[0001]
Absorbable filter (1) characterized by the fact that it comprises: a circumferential element (2) in contact with a vessel; and a plurality of absorbable capture elements (30-32, 40, 41) attached to the circumferential element (2) to capture substances that flow in the vessel for a limited time, wherein the individual elements of the plurality of absorbable capture elements (30-32, 40, 41) are connected to adjacent absorbable capture elements by means of an absorbable internal capture element (60) coupled with the plurality of absorbable capture elements (30-32, 40, 41); characterized by the fact that the circumferential element (2) is defined by a first lattice spacing comprising a circumferential lattice spacing of the filter (1) around the circumferential element (2); the plurality of absorbable capture elements (30-32, 40, 41) is defined by a second lattice spacing comprising a lattice spacing in cross section of the filter (1) formed by the plurality of absorbable capture elements (30-32, 40, 41) transverse to a longitudinal axis of the filter (1); and the individual elements of the plurality of absorbable capture elements (30-32, 40, 41) are defined by the second lattice spacing to intersect and / or wrap around other individual elements of the plurality of absorbable capture elements (30-32, 40, 41) in a plurality of separate locations along a given absorbable capture element, the first truss spacing being less than the second truss spacing.
[0002]
Filter (1) according to claim 1, characterized by the fact that the internal capture element (60) is woven through the plurality of absorbable capture elements (30-32, 40, 41) and the plurality of absorbent elements absorbable catches (30-32, 40, 41) form a catch basket (101).
[0003]
Filter (1) according to claim 2, characterized by the fact that the circumferential element (2) and the catch basket (101) are constructed of a single continuous absorbable filament.
[0004]
Filter (1) according to claim 1, characterized by the fact that the plurality of absorbable capture elements (30-32, 40, 41) comprise proximal capture elements (30, 41), intermediate elements and capture (31 , 40), and distal capture elements (32) configured to degrade sequentially so that the filter decomposition starts with the proximal capture elements (30, 41) and then progresses through the intermediate section capture elements (31, 40) and the distal capture elements (32) in sequential order.
[0005]
Filter (1), according to claim 1, characterized by the fact that the plurality of absorbable capture elements (30-32, 40, 41) are manufactured from absorbable materials selected from the group consisting of polydioxanone, polytrimethylene carbonate, polyglactin, polyglycolic acid, poly Lactic acid, polyglecaprone, polyglitone, and polylacticoglycolic acid.
[0006]
Filter (1) according to claim 1, characterized by the fact that the plurality of absorbable capture elements (30-32, 40, 41) are absorbable sutures.
[0007]
Filter (1) according to claim 1, characterized by the fact that the circumferential element (2) is non-absorbable.
[0008]
Filter (1), according to claim 1, characterized by the fact that the circumferential element (2) is manufactured from materials selected from the group consisting of nickel-titanium alloy (Nitinol), cobalt-chromium alloy nickel (Elgiloy), cobalt-chromonickel-molybdenum alloy (Phynox), stainless steel, MP35N alloy, titanium alloy, platinum alloy, niobium alloy, cobalt alloy, or tantalum wire.
[0009]
Filter (1) according to claim 1, characterized by the fact that the plurality of absorbable capture elements (30-32, 40, 41) form an absorbable capture basket (101) fixed to the circumferential element (2).
[0010]
Filter (1), according to claim 9, characterized by the fact that the catch basket (101) is manufactured from materials selected from the group consisting of polypropylene, polypropylene encapsulated in polydioxanone, polypropylene co-knitted with polyglycolic acid fibers, polyethylene terephthalate, ePTFE, polydioxanone, polytrimethylene carbonate, polyglactin, polyglycolic acid, poly Lactic acid, polyglecaprone, polyglitone, and polylacticoglycolic acid.
[0011]
Filter (1) according to claim 9, characterized by the fact that the catch basket (101) is a biocompatible mesh.
[0012]
Filter (1), according to claim 9, characterized by the fact that the catch basket (101) is manufactured from materials used in the construction of a biocompatible mesh selected from the group consisting of polypropylene, polypropylene encapsulated by polydioxanone, polypropylene co-knitted with polyglycolic acid fibers, polyethylene terephthalate and ePTFE.
[0013]
Filter (1) according to claim 9, characterized in that at least a portion of the circumferential element (2) is non-absorbable.
[0014]
Filter (1) according to claim 13, characterized by the fact that the circumferential element (2) is made of materials that include, but are not limited to, nickel-titanium alloy (Nitinol), cobalt-chromium alloy -nickel (Elgiloy), cobalt-chromonickel-molybdenum alloy (Phynox), stainless steel, MP35N alloy, titanium alloy, platinum alloy, niobium alloy, cobalt alloy, or tantalum wire.
[0015]
Filter (1) according to claim 1 or 9, characterized by the fact that the circumferential element (2) is absorbable.
[0016]
Filter (1) according to claim 1 or 9, characterized by the fact that the circumferential element (2) is made of absorbable materials selected from the group consisting of polydioxanone, polytrimethylene carbonate, polyglactin, polyglycolic acid, acid poly Lactic acid, polyglecaprone, polyglitone, or polylacticoglycolic acid.
[0017]
Filter (1) according to claim 1 or 9, characterized by the fact that the circumferential element (2) comprises an anchor or barb element for fixing to a vessel.
[0018]
Filter (1) according to claim 1 or 9, characterized by the fact that the circumferential element (2) contains a bioactive surface for anticoagulation.
[0019]
Filter (1) according to claim 1 or 9, characterized by the fact that the circumferential element (2) is a stent.
[0020]
Filter (1) according to claim 1, characterized by the fact that the circumferential element (2) comprises a braided circumferential element and the plurality of absorbable capture elements (30-32, 40, 41) form a capture basket (101) absorbable.
[0021]
Filter (1) according to claim 20, characterized by the fact that the braided circumferential element and capture basket (101) are constructed of a single absorbable continuous filament.
[0022]
Filter (1) according to claim 20, characterized by the fact that the twisted circumferential element and the catch basket (101) are constructed of a plurality of absorbable filaments.
[0023]
Filter (1), according to claim 20, characterized by the fact that the integrated circumferential element and the capture basket (101) are manufactured from absorbable materials selected from the group consisting of polyoxioxone, polytrimethylene carbonate, polyglactin, polyglycolic acid, poly Lactic acid, polyglecaprone, polyglitone, and polylacticoglycolic acid.
[0024]
Filter (1), according to claim 20, characterized by the fact that the braided circumferential element is braided to offer diametrically expandable and compressible tubular characteristics to accommodate minimally invasive placement through a catheter.
[0025]
Filter (1) according to claim 20, characterized by the fact that the radial force of the braided circumferential element exerted on the vessel lumen is selected based on the angle of intersection with the braided elements comprising the circumferential element (2), composition and material size, and / or the outer diameter of the circumferential element (2).
[0026]
Filter (1) according to claim 20, characterized by the fact that the catch basket (101) is formed by loops sequentially interlocked from loops adjacent to the circumferential element (2) and extending loops to the apex in a way periodic to form a conical capture basket (101) with a filter resolution determined by the striking frequency.
[0027]
Filter (1), according to claim 20, characterized by the fact that the circumferential element (2) and / or the capture basket (101) contains a bioactive surface for anticoagulation.

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法律状态:
2018-12-18| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2020-07-28| B07A| Application suspended after technical examination (opinion) [chapter 7.1 patent gazette]|

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2020-12-01| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-01-26| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 23/02/2012, OBSERVADAS AS CONDICOES LEGAIS. |

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US13/036.351|2011-02-28|

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US13/036,351|US20120221040A1|2011-02-28|2011-02-28|Absorbable Vascular Filter|

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