Patent Application
20060020285
In the human cardiovascular and circulatory system, the consistency of blood remains liquid enough for the blood cells and other molecules to travel smoothly through the arteries and veins. Sometimes, however, clots will form in a process called coagulation. When clots or other blood-borne clumps of tissue migrate through the circulatory system, they are called emboli; a single migrating clot is called an embolus or an embolism.
A pulmonary embolism is a clot that travels through the venous system and eventually lodges in the pulmonary artery, which carries blood from the heart to the lungs. This can obstruct the blood supply to the lungs, which is potentially fatal and should be treated as an emergency.
Many pulmonary emboli result from a condition called deep vein thrombosis (DVT). DVT is the formation of a blood clot in the veins embedded deep in the muscles, usually in the lower leg and sometimes in the pelvis or groin.
Vena cava filters, tiny nets, help prevent emboli from traveling through the heart and into the lungs. Most commonly, vena cava filters are inserted into the inferior vena cava, a large vein that carries blood from the lower extremities.
Vena cava filters are normally metallic, umbrella-shaped devices that catch blood clots to prevent them from traveling to the lungs and causing a pulmonary embolism. Vena cava filters usually are used when drug therapy, such as treatment with blood-thinners, has failed or is considered inadequate, or when drug therapy would cause other dangerous medical conditions.
The procedure is safe and effectively reduces the risk of pulmonary embolism in most people when performed by a practitioner who is skilled in filter insertion and when complemented by drug therapies.
People most likely to receive a vena cava filter are those at risk for pulmonary embolism and those for whom drug or other therapy is considered inadequate. Vena cava filters are also inserted to protect trauma patients from pulmonary embolism associated with their injuries.
The procedure for placing a vena cava filter in a patient usually requires that the physician administer a local anesthetic at the insertion site, either the arm, neck, or groin, and makes an incision. Patients may also receive a muscle relaxant for additional comfort. Alternatively, the procedure may be performed while the patient is under general anesthesia.
The physician then inserts the collapsed filter into the incision via a catheter (a long, thin, flexible tube) and advances the filter to the vena cava. The physician then deploys the filter in the vein at the target location, removes the insertion device, and closes the incision. The procedure generally takes from 10 to 40 minutes. Antibiotics are prescribed as necessary to minimize the risk of infection.
Patients are likely to remain in the hospital until the supervising physician confirms that the filter is properly fixed in the vena cava and that there are no complications from the procedure. The presence of a vena cava filter does not affect daily routines or the use of other medications. Some patients may remain on anticoagulant drug therapy to reduce the risk of post-insertion clot formation, or risk enlarging a pre-existing clot.
However, there are known complications that may arise in any vena cava filter placement even though known vena cava filters are about 98 percent successful in preventing symptomatic pulmonary embolism. These known filter devices and their placement procedures can be associated with surgical and anesthesia complications to include: bleeding at the insertion site; anesthesia-associated complications such as an allergic reaction or breathing problems; stroke; pulmonary embolism; and clots. And, as is well known in the field, these complications are not only serious to the patient's health, but they can also be fatal.
Thrombosis of the inferior vena cava (IVC) filter after filter placement is frequently reported and may occur with all types of filter presently used in the field. The occurrence of thrombosis can be delayed from hours to several months after the filter placement, but seems more frequent during the first 3 months. Continued anticoagulation therapy has not been shown to prevent IVC thrombosis.
Studies have also shown adverse flow dynamics, such as increased pressure gradients, in the filters with high clot-trapping capacity. Accordingly a device that has a high clot capture efficiency while minimizing the potential for increased pressure gradient is desirable.
Accordingly, what is needed is a device and method that can further reduce these serious and fatal complications in a more reliable and predictable manner. To date, there have been no known filter devices that are designed in such a manner that can eliminate these complications on a consistent basis, particularly providing for the elimination of complications that may be attributed to pulmonary embolism and blood clots.
The present invention is a novel filter device and method for filtering blood in a vessel that is more highly effective in capturing clots and preventing pulmonary embolism over the known prior art devices and techniques.
The present invention is a novel filter device and novel method for filtering fluid or blood in a vessel or organ that is more highly effective in capturing clots, emboli, particulate matter and particles and preventing pulmonary embolism over the known prior art devices and techniques The device will also avoid plugging up and restricting blood flow.
The present invention is directed to various embodiments of devices and methods for trapping or capturing emboli in a vessel of patient's body or organ.
In one embodiment, the present invention is a device for capturing an embolus within a vessel of a patient's body, the device comprising:
In another embodiment, the present invention is a device for trapping an embolus within a vessel, the device comprising:
In another embodiment, the present invention is a device for trapping an embolus within a vessel, the device comprising:
Another embodiment for the present invention is directed to a method for capturing an embolus within a vessel of a patient's body, the method comprising the steps of:
The method according to the present invention further includes the step of placing the device within the vessel of the patient's body by moving the device from a collapsed state to an expanded state when placed within a vessel. Other steps include anchoring the device to an inner wall of the vessel, for instance, through using a plurality of barbs.
Another embodiment for the present invention is directed toward a method for capturing an embolus within a vessel of a patient's body, the method comprising the steps of:
Another method of the present invention is a method for trapping an embolus within a vessel of a patient's body, the method comprising the steps of:
The method further includes the step of placing the device within the vessel of the patient's body by moving the mesh panels of the device from a collapsed state to an expanded state when placed within a vessel and anchoring the device to an inner wall of the vessel by using an anchoring mechanism or plurality of anchoring mechanisms such as a plurality of barbs.
Another method for the present invention is a method for trapping an embolus within a vessel of a patient's body, the method comprising the steps of:
For example, the pore size can vary from a larger size pore at one end of the device to a smaller size pore at an opposite end of the device wherein the pore size decreases throughout the entire length of the device, i.e. pore size decreases from the one end to the opposite end of the device such as found with depth type filter devices. The at least one helix having a plurality of turns helically arranged around a longitudinal axis can vary in pitch. This pitch may decrease to zero, to the point where the helix ends by making a full revolution and contacts itself. Additionally, in all embodiments of the present invention, the pore size can be a uniform size throughout the device, i.e. from one end of the device to the opposite end of the device.
The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to organization and methods of operation, together with further objects and advantages thereof, may be understood by reference to the following description, taken in conjunction with the accompanying drawings in which:
The present invention is a filter device, generally designated 50, having a helical design that is either surface type filter (
The filter device 50 has a helix 55 (as either a single helix or double helix as better described later on below) that is particularly useful for trapping and capturing clots, emboli, particulate matter, particles and thrombus that are migrating or circulating throughout the circulatory system of the patient or are in danger of breaking apart from attached tissue or structure within the body and migrating or circulating throughout the circulatory system of the patient. As defined herein, the term “clot”, “clots”, “embolus”, “embolism”, “emboli”, “particulate”, “particulate matter”, “matter”, “particles”, “filtrate”, “thrombus”, and “thrombi” have the same meaning for purposes of this disclosure and are used interchangeably throughout and are generally designated as reference numeral 20.
The helix 55 of filter device 50 is made of a mesh material 52 having a plurality of pores 53 throughout the mesh 52. For example, the mesh 52 consists of a plurality of interlocking strands or fibers or an array of pores 53 made and arranged in the material 52 itself such as through cutting, etching, stamping or the like. Details for the pores 53 are addressed below.
The material 52 is any form of material. In one embodiment, the material 52 is a self-expanding material such as shape-memory material which can be a metal alloy such as nickel titanium alloy (nitinol). In another embodiment, the material 52 is a stainless steel alloy. Alternatively, the mesh material 52 is a polymer material. The polymer can be biodegradable and/or bioabsorbable. As used herein, the term “biodegradable” is defined as the breaking down or the susceptibility of a material or component to break down or be broken into products, byproducts, components or subcomponents over time such as days, weeks, months or years. As used herein, the term “bioabsorbable” is defined as the biologic elimination of any of the products of degradation by metabolism and/or excretion.
The expanded shape of the filter 50 comprises at least one helix 55, for example a single helix (
It is preferable that the mesh 52 of each turn 65 is sloped, slanted, inclined or curved away from ID of helix 55 to OD of helix 55 such as depicted in the Figs., or alternatively, the helix 55 may have no incline or inclined toward the longitudinal axis. Since the mesh 52 is slanted or curved outwardly from ID to OD for each turn 65 of helix 55, fluid medium is forced and channeled toward the outer circumferential periphery of the helix 55. The panels 60 design for the helix 55 in the embodiments depicted in
The helix 55 has a plurality of turns 65 helically arranged around a longitudinal axis that can vary in pitch. This pitch may decrease to zero, to the point where the helix 55 ends or terminates by making a full revolution and contacts itself.
In some embodiments according to the present invention, the helix 55 includes a spine 57 as best illustrated in
The filter device 50 is expandable from a compressed, closed, pre-deployed or collapsed state to an open, deployed or expanded state such as partially depicted in
Additionally, when moved to the open, deployed or expanded state, the helix 55 embeds itself in the wall 12 of the vessel 10 such as shown in
The size for each pore 53 is ≧120 mm. Additionally, in all embodiments of the present invention, the pore size can be a uniform size throughout the entire length of the device 50, i.e. from one end of the device 50 to the opposite end of the device 50.
The filter device 50 according to the present invention (all embodiments) provides the ability to expose a greater surface area of the filter device 50 due to the unique helix 55 feature. Based on its helical design, the filter device 50 permits a smaller pore structure 53 (over the known filters and filtering methods) because the possibility of stopping venous flow is eliminated. Accordingly, smaller sized clots 20, for instance clots 20 having a size ≧120 μm, can be targeted and captured, thereby reducing risk to the patient, i.e. the risk of these smaller size clots 20 causing harm.
Moreover, in all embodiments of the present invention, the pore sizes of the filter device 50 can vary from one end of the device 50 to an opposite end of the device 50. For example, as best illustrated in
The structure of the helix 55 is an expanded mesh 52 that creates the surface filter effect. Any particulate or clot 20 that approaches the filter device 50 according to the present invention encounters what appears to be a solid cylindrical impediment in the lumen 15 of vessel 10 (since OD of helix 55 circumferentially is expanded to and circumferentially conforms to inner wall 12 of vessel 10 as best shown in
There are several advantages to the helical filter design of the filter device 50 according to the present invention, for example, the ability of the helix 55 of filter device 50 to filter large amounts of filtrate (clots 20) and completely avoid clogging or plugging the lumen 15 of vessel 10, i.e. vena cava 10 in this example. This is especially important since prior art filters increase the resistance in the lumen 15 of vessel 10 as they are eventually clogged or plugged by particulate matter (clots 20), eventually restricting the flow within vessel 10 thereby cutting off or occluding fluid flow altogether.
The helical filter design of filter device 50 of the present invention captures the filtrate 20 by inertial impaction, or diverts it to the outside edges or periphery of the helix 55 thereby trapping it, while allowing the fluid medium (liquid or gas) to pass around the new obstruction created by the captured filtrate 20.
Other advantages of the filter device 50 of the present invention include the ability to generate a filter having different pore sizes from beginning to end as depicted in
Other advantages for the filter device 50 of the present invention-relate to its delivery, deliverability and manufacturability. For example, as depicted in
As shown in
One geometry, merely used as an example, is depicted in
Furthermore, variations for the filter device 50 are also contemplated herein according to the present invention. For example, as mentioned above, the helical turns 65 of the filter device 50 can have a variable pitch. Additionally, one end of the filter device 50 can coil in on itself, thereby providing an absolute type filter and eliminate any perception that a clot 20 may travel passed the filter 50.
Moreover, the filter device 50 is optionally coated with a drug such as a cytotoxic drug or cytostatic drug in order to make the filter device 50 a drug eluting device for treatment of disease that responds to cytotoxic drugs (for example paclitaxel) or cytostatic drugs (for example one of the rapamycins) respectively. As used herein, the term “drug” or “drugs” are used interchangeably herein and define an agent, drug, compound, composition of matter or mixture thereof which provides some therapeutic, often beneficial, effect such as being cytotoxic or cytostatic as two examples.
This includes pesticides, herbicides, germicides, biocides, algicides, rodenticides, fungicides, insecticides, antioxidants, plant growth promoters, plant growth inhibitors, preservatives, antipreservatives, disinfectants, sterilization agents, catalysts, chemical reactants, fermentation agents, foods, food supplements, nutrients, cosmetics, drugs, vitamins, sex sterilants, fertility inhibitors, fertility promoters, microorganism attenuators and other agents that benefit the environment of use. As used herein, the terms further include any physiologically or pharmacologically active substance that produces a localized or systemic effect or effects in animals, including warm blooded mammals, humans and primates; avians; domestic household or farm animals such as cats, dogs, sheep, goats, cattle, horses and pigs; laboratory animals such as mice, rats and guinea pigs; fish; reptiles; zoo. and wild animals; and the like. The active drug that can be delivered includes inorganic and organic compounds, including, without limitation, drugs which act on the peripheral nerves, adrenergic receptors, cholinergic receptors, the skeletal muscles, the cardiovascular system, smooth muscles, the blood circulatory system, synoptic sites, neuroeffector junctional sites, endocrine and hormone systems, the immunological system, the reproductive system, the skeletal system, autacoid systems, the alimentary and excretory systems, the histamine system and the central nervous system. Suitable agents may be selected from, for example, proteins, enzymes, hormones, polynucleotides, nucleoproteins, polysaccharides, glycoproteins, lipoproteins, polypeptides, steroids, hypnotics and sedatives, psychic energizers, tranquilizers, anticonvulsants, muscle relaxants, antiparkinson agents, analgesics, anti-inflammatories, local anesthetics, muscle contractants, blood pressure medications and cholesterol lowering agents including statins, antimicrobials, antimalarials, hormonal agents including contraceptives, sympathomimetics, polypeptides and proteins capable of eliciting physiological effects, diuretics, lipid regulating agents, antiandrogenic agents, antiparasitics, neoplastics, antineoplastics, hypoglycemics, nutritional agents and supplements, growth supplements, fats, ophthalmics, antienteritis agents, electrolytes and diagnostic agents.
Examples of the therapeutic agents or drugs useful in this invention include prochlorperazine edisylate, ferrous sulfate, aminocaproic acid, mecaxylamine hydrochloride, procainamide hydrochloride, amphetamine sulfate, methamphetamine hydrochloride, benzphetamine hydrochloride, isoproteronol sulfate, phenmetrazine hydrochloride, bethanechol chloride, methacholine chloride, pilocarpine hydrochloride, atropine sulfate, scopolamine bromide, isopropamide iodide, tridihexethyl chloride, phenformin hydrochloride, methylphenidate hydrochloride, theophylline cholinate, cephalexin hydrochloride, diphenidol, meclizine hydrochloride, prochlorperazine maleate, phenoxybenzamine, thiethylperazine maleate, anisindione, diphenadione, erythrityl tetranitrate, digoxin, isoflurophate, acetazolamide, methazolamide, bendroflumethiazide, chlorpropamide, tolazamide, chlormadinone acetate, phenaglycodol, allopurinol, aluminum aspirin, methotrexate, acetyl sulfisoxazole, hydrocortisone, hydrocorticosterone acetate, cortisone acetate, dexamethasone and its derivatives such as betamethasone, triamcinolone, methyltestosterone, 17-.beta.-estradiol, ethinyl estradiol, ethinyl estradiol 3-methyl ether, prednisolone, 17-.beta.-hydroxyprogesterone acetate, 19-nor-progesterone, norgestrel, norethindrone, norethisterone, norethiederone, progesterone, norgesterone, norethynodrel, indomethacin, naproxen, fenoprofen, sulindac, indoprofen, nitroglycerin, isosorbide dinitrate, propranolol, timolol, atenolol, alprenolol, cimetidine, clonidine, imipramine, levodopa, chlorpromazine, methyldopa, dihydroxyphenylalanine, theophylline, calcium gluconate, ketoprofen, ibuprofen, atorvastatin, simvastatin, pravastatin, fluvastatin, lovastatin, cephalexin, erythromycin, haloperidol, zomepirac, ferrous lactate, vincamine, phenoxybenzamine, diltiazem, milrinone, captropril, mandol, quanbenz, hydrochlorothiazide, ranitidine, flurbiprofen, fenbufen, fluprofen, tolmetin, alclofenac, mefenamic, flufenamic, difuninal, nimodipine, nitrendipine, nisoldipine, nicardipine, felodipine, lidoflazine, tiapamil, gallopamil, amlodipine, mioflazine, lisinopril, enalapril, captopril, ramipril, enalaprilat, famotidine, nizatidine, sucralfate, etintidine, tetratolol, minoxidil, chlordiazepoxide, diazepam, amitriptylin, and imipramine. Further examples are proteins and peptides which include, but are not limited to, insulin, colchicine, glucagon, thyroid stimulating hormone, parathyroid and pituitary hormones, calcitonin, renin, prolactin, corticotrophin, thyrotropic hormone, follicle stimulating hormone, chorionic gonadotropin, gonadotropin releasing hormone, bovine somatotropin, porcine somatropin, oxytocin, vasopressin, prolactin, somatostatin, lypressin, pancreozymin, luteinizing hormone, LHRH, interferons, interleukins, growth hormones such as human growth hormone, bovine growth hormone and porcine growth hormone, fertility inhibitors such as the prostaglandins, fertility promoters, growth factors, and human pancreas hormone releasing factor.
Moreover, drugs or pharmaceutical agents useful for the filter device 50 include: antiproliferative/antimitotic agents including natural products such as vinca alkaloids (i.e. vinblastine, vincristine, and vinorelbine), paclitaxel, epidipodophyllotoxins (i.e. etoposide, teniposide), antibiotics (dactinomycin (actinomycin D) daunorubicin, doxorubicin and idarubicin), anthracyclines, mitoxantrone, bleomycins, plicamycin (mithramycin) and mitomycin, enzymes (L-asparaginase which systemically metabolizes L-asparagine and deprives cells which do not have the capacity to synthesize their own asparagine); antiplatelet agents such as G(GP)IIbIIIa inhibitors and vitronectin receptor antagonists; antiproliferative/antimitotic alkylating agents such as nitrogen mustards (mechlorethamine, cyclophosphamide and analogs, melphalan, chlorambucil), ethylenimines and methylmelamines (hexamethylmelamine and thiotepa), alkyl sulfonates-busulfan, nirtosoureas (carmustine (BCNU) and analogs, streptozocin), trazenes—dacarbazinine (DTIC); antiproliferative/antimitotic antimetabolites such as folic acid analogs (methotrexate), pyrimidine analogs (fluorouracil, floxuridine, and cytarabine), purine analogs and related inhibitors (mercaptopurine, thioguanine, pentostatin and 2-chlorodeoxyadenosine{cladribine}); platinum coordination complexes (cisplatin, carboplatin), procarbazine, hydroxyurea, mitotane, aminoglutethimide; hormones (i.e. estrogen); anticoagulants (heparin, synthetic heparin salts and other inhibitors of thrombin); fibrinolytic agents (such as tissue plasminogen activator, streptokinase and urokinase), aspirin, dipyridamole, ticlopidine, clopidogrel, abciximab; antimigratory; antisecretory (breveldin); antiinflammatory: such as adrenocortical steroids (cortisol, cortisone, fludrocortisone, prednisone, prednisolone, 6α-methylprednisolone, triamcinolone, betamethasone, and dexamethasone), non-steroidal agents (salicylic acid derivatives i.e. aspirin; para-aminophenol derivatives i.e. acetominophen; indole and indene acetic acids (indomethacin, sulindac, and etodalac), heteroaryl acetic acids (tolmetin, diclofenac, and ketorolac), arylpropionic acids (ibuprofen and derivatives), anthranilic acids (mefenamic acid, and meclofenamic acid), enolic acids (piroxicam, tenoxicam, phenylbutazone, and oxyphenthatrazone), nabumetone, gold compounds (auranofin, aurothioglucose, gold sodium thiomalate); immunosuppressives: (cyclosporine, tacrolimus (FK-506), sirolimus (rapamycin), azathioprine, mycophenolate mofetil); angiogenic agents: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) platelet derived growth factor (PDGF), erythropoetin,; angiotensin receptor blocker; nitric oxide donors; anti-sense oligionucleotides and combinations thereof; cell cycle inhibitors, mTOR inhibitors, growth factor signal transduction kinase inhibitors, chemical compound, biological molecule, nucleic acids such as DNA and RNA, amino acids, peptide, protein or combinations thereof.
It is to be understood that the use of the term “drug” or drugs” includes all derivatives, analogs and salts thereof and in no way excludes the use of two or more such drugs.
The one or more drugs are coated on the filter device 50 itself or any desired portion of the device 50, for example, the outer circumferential edge of the helical turns 65. Moreover, the drug can be used with a polymer coating or the drug can be incorporated into the mesh material 52 of the device 50 itself when the mesh material 52 itself is made of a polymer material as mentioned above.
As shown in
As mentioned above, the deployment mechanism for the filter device 50 may be due to the material 52 itself (when the material 52 is shape-memory material) and will be in the form of a helically wrapped tube (
The mesh material 52 may be of any form, i.e. from a self-expanding material such as nitinol to a stainless steel material requiring a delivery mechanism to form it into its final shape, or it may be a polymer or blend of polymers, to name a few examples. The filter device is also made to be retractable (if desired). For instance, due to the nature of the helix design, by applying a twisting action reverse (reverse torque) to that which expanded the filter device when originally deployed in the vessel 10, the filter device 50 can be collapsed and retracted and withdrawn from the vessel 10 and the patient's body. The material 52 can also be of the type that requires a delivery mechanism to form filter device 50 into its final helical shape.
In as much as the foregoing specification comprises preferred embodiments of the invention, it is understood that variations and modifications may be made herein, in accordance with the inventive principles disclosed, without departing from the scope of the invention.
While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will now occur to those skilled in the art without departing from the invention. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.
