Claims:WE CLAIMS
1. An embolization coil for thrombosis, the embolization coil comprising:
i. a coiled tube including a plurality of windings; and
ii. a plurality of fibers, the fibers being wrapped around one or more of the plurality of windings;
wherein the embolization coil includes a 4.0% (w/w) to 5.0% (w/w) of the fibers and 95.0% (w/w) to 96.0% (w/w) of the coiled tube.
2. The embolization coil as claimed in claim 1 wherein the plurality of fibers is wrapped around the windings in one of a consecutive manner, alternative manner or one after two windings.
3. The embolization coil as claimed in claim 1 wherein the plurality of winding in the coiled tube includes 125-140 windings.
4. The embolization coil as claimed in claim 1 wherein the embolization coil is coated with one of hydrogel formulation or an antifibrinolytic agent.
5. The embolization coil as claimed in claim 1 wherein the embolization coil is compatible with a catheter having 4F diameter.
6. A method of loading an embolization coil in a delivery system, the method including:
placing an embolization coil on a distal end of a loading wire to form a coil loaded wire;
placing a loader on a proximal end of the coil loaded wire;
inserting the coil loaded wire with the loader inside a lumen of a loading tube towards a distal end to partially load the embolization coil in the loading tube; and
pushing the loader towards the distal end of the loading tube to fully load the embolization coil in the loading tube.
7. The method of loading an embolization coil in a delivery system as claimed in claim 6 wherein the inserting the coil loaded wire inside the lumen of the loading tube includes manual sliding.
8. The method of loading an embolization coil in a delivery system as claimed in claim 6 wherein the pushing the loader includes manual pushing.
9. The method of loading an embolization coil in a delivery system as claimed in claim 6 wherein the loading wire is pulled back from the proximal end of the loading tube once the embolization coil is fully loaded.
10. The method of loading an embolization coil in a delivery system as claimed in claim 6 wherein the loader is pulled back from the proximal end of the loading wire. , Description:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

1. TITLE OF THE INVENTION:
EMBOLIZATION COIL AND DELIVERY SYSTEM THEREOF

2. APPLICANTS:
Meril Life Sciences Pvt Ltd, an Indian Company of the address, Survey No. 135/139 Bilakhia House, Muktanand Marg, Chala, Vapi-Gujarat 396191, India

3. The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
[001] The present invention relates to an embolization coil, more specifically the present invention relates to fiber content in the embolization coil and a delivery system of the embolization coil.
BACKGROUND
[002] Embolization coils are used to block the blood flow through a body vessel in the peripheral vasculature. Embolization coils are well known for treatment of various AVMs (arteriovenous malformations), AVFs (arteriovenous fistulas), vericoceles and other arteriovenous abnormalities in the body. The embolization coils may be also used to for example, repair abnormal shunts between arteries and veins, prevent and/or reduce blood flow to tumours, aneurysm, stop haemorrhaging as a result of trauma, and/or stabilize wall of arteries, veins, aneurysms to prevent rupture.
[003] An embolization coil can be made by coiling wire in a helical manner and/or attachment of fibers on the coiled wire. The fibers may facilitate embolization and/or blockage in a blood vessel. Therefore, the amount of fiber present on the embolization coil is a crucial factor for embolization in a patient. Conventional embolization coils may not include appropriate amount of the fibers due to which delayed embolization or early embolization even before deployment at a targeted treatment site may occur.
[004] Further, the embolization coil may be deployed at a required implantation site in a patient with the help of a delivery system. The profile of the embolization coil and the delivery system may be a critical factor for accurate deployment of the embolization coil in a targeted embolization location. However, the loading of the embolization coil using the conventional delivery method may require numerous steps and use of various components which might make the process of loading the embolization coil complex and cumbersome. Further, the conventional delivery systems for the embolization coil pose increased the risk of damage to fibers of the embolization coil leading to a reduction in efficiency of the device.
SUMMARY
[005] The present invention discloses an embolization coil. The embolization coil includes a coiled tube including a plurality of windings, a plurality of fibers, the fibers being wrapped around one or more of the plurality of windings. Further, the embolization coil includes a 4.6% (w/w) of the fibers and 95.4% (w/w) of the coiled tube. Further, the present invention discloses a method of loading the embolization coil in a delivery system. The method includes placing an embolization coil on a distal end of a loading wire followed by placing a loader on a proximal end of the loading wire. Further, the method includes inserting the loading wire with the loader inside a lumen of a loading tube towards a distal end to partially load the embolization coil in the loading tube followed by pushing the loader towards the distal end of the loading tube to fully load the embolization coil in the loading tube.
BRIEF DESCRIPTION OF DRAWINGS
[006] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[007] FIG.1 illustrates a front view of an embolization coil in accordance with an embodiment of the present invention.
[008] FIG.2 illustrates a front view of a delivery system in accordance with an embodiment of the present invention.
[009] FIG.3 illustrates a flow chart involved in the loading of the embolization coil in the delivery system in accordance with an embodiment of the present invention.
[010] FIG.4a illustrates the embolization placed over a wire in accordance with an embodiment of the present invention.
[011] FIG.4b illustrates insertion of the embolization coil inside the tube in accordance with an embodiment of the present invention.
[012] FIG.4c illustrates the loading of the embolization coil inside the tube in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF DRAWINGS
[013] Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms "include" and "comprise", as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "coupled with" and "associated therewith", as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like; definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.
[014] Particular embodiments of the present disclosure are described hereinbelow with reference to the accompanying drawings, however, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
[015] The present invention relates to an embolization coil and a delivery system for the embolization coil. The embolization coil may be used to occlude vessels in a variety of medical applications. In various embodiments, the embolization coil can be used in intracranial, peripheral, pulmonary, internal iliac, gastro-duodenal, renal arteries and/or in the tapered blood vessels. The embolization coil may restrict blood flow by increasing thrombosis and/or prevents excessive blood flow in the diseased peripheral vasculature.
[016] The embolization coil may include fibers that can enhance thrombosis in the vessel. The embolization coil may include a plurality of densely packed fibers throughout the length of the embolization coil. The embolization coil may include 4.0% (w/w) to 5.0% (w/w) content of the fibers. In an embodiment, the embolization coil includes 4.6% (w/w) content of the fibers. The said content of fibers may increase the surface area of the embolization coil leading to rapid thrombosis at a treatment site. In another embodiment, the delivery system of the embolization coil maintains the embolization coil in a straight configuration and/or is compatible with a guide wire catheter.
[017] Now referring specifically to drawings, FIG. 1 illustrates an embolization coil 100. The embolization coil 100 may control internal bleeding, prevents blood supply to the diseased area and/or may reduce internal pressure in diseased peripheral arteries as well as in aneurysm wall. The embolization coil 100 includes a coiled tube 10 and a plurality of fibers 20.
[018] The coiled tube 10 of the embolization coil 100 may be formed by coiling a single wire or a plurality of wires. In an embodiment, the coiled tube 10 includes a single wire in a coiled configuration. The coiled tube 10 may be fabricated by coiling the wire on a mandrel.
[019] The wire may be made of shape memory materials. The shape memory materials may include without limitation, stainless steel, nickel-titanium alloy, platinum-tungsten alloy, nickel-chromium alloy, etc. In an embodiment, the wire is made of platinum-tungsten (92% platinum and 8% tungsten) alloy due to its relatively high degree of biocompatibility and fatigue resistance. The wire may have a thickness in a range of 20 micron-100 micron, preferably 70 micron-80 micron. The tensile strength of the wire may be in a range of 4900kg/cm2 – 8450 kg/cm2, preferably 6300 kg/cm2 – 7050 kg/cm2.
[020] The coiled tube 10 may include a plurality of windings. The windings may range between 125 to 140. In an embodiment, the number of windings is 130.
[021] The coiled tube 10 includes a lumen 14. The diameter of the lumen 14 may be in a range of 0.20 mm to 0.68 mm, preferably 0.21 mm to 0.67 mm. The coiled tube 10 may include an outer diameter in a range of 0.36 mm-0.83 mm, preferably 0.37 mm-0.82 mm. In an embodiment, the diameter of the lumen 14 is 0.22mm and the outer diameter is 0.38mm. In another embodiment, the diameter of the lumen is 0.66mm and the outer diameter is 0.81mm.
[022] The embolization coil 100 may include the fibers 20 present on each winding of the coiled tube 10. The fibers 20 may be made of biodegradable and/or non-biodegradable material. The biodegradable material may include without limitation, PGLA (poly-glycolic/lactic acid), poly-caprolactone (PCL), poly-lactic acid (PLA), poly-glycolic acid (PGA), poly(p-dioxanone), poly(tartronic acid), poly([3 malonic acid), poly(propylene fumarate), poly(anhydrides), and tyrosine-based polycarbonates. The non-biodegradable material may include without limitation textured polyester, polyethylene, polyacrylic, polypropylene, polyvinyl chloride, polyamides such as nylon, e. g., nylon 6.6, polyurethanes, polyvinyl pyrrolidone, polyvinyl alcohols, polyvinyl acetate, cellulose acetate, polystyrene, poly-tetrafluoroethylene, polyesters such as polyethylene terephthalate (dacron), silk, cotton etc. In an embodiment of the present invention, the fibers 20 are made of textured nylon which may help to increase the rate of embolization in diseased arteries.
[023] In an embodiment, a bunch of fibers 20 may be wound around the wire in each winding as represented in FIG. 1. Alternately, each coil may include one fiber 20. The fibers 20 may be wound in a way such that two free ends 20a, 20b are formed. The free ends 20a and 20b may correspond to two oppositely facing sides of the coiled tube 10. The fibers 20 may enhance thrombosis and/or may help to hold the embolization coil 100 at an implantation site.
[024] Further, the fiber(s) 20 may be wound along the circumference of the wire at a predefined location of each winding as illustrated in FIG. 1. The predefined location may be any fixed location in the coil. As further indicated in FIG. 1, the predefined location of each winding is the same. The fibers 20 may be inserted in the windings by means of without limitation winding, wrapping, glue, etc. In an embodiment, the fibers 20 are manually wrapped around the predefined location in a spiral configuration as illustrated in FIG.1. Following wrapping around the wire, the fibers 20 may be cut by means of medical scissors. The fibers 20 may be cut in a length of 3mm to 20mm, preferably 4mm to 15mm, more preferably 5mm to 10mm. In an embodiment, the length of the fibers 20 is 10mm. The length of all fibers 20 utilized in the embolization coil 100 may be the same or different. Further, the thickness of the fibers 20 may be dependent upon the thickness of the wire used for making the coiled tube 10. The thickness of the fibers 20 may be in a range of 0.20mm to 0.30mm. In an embodiment, the thickness of the fibers 20 is 0.27mm.
[025] The fibers 20 may be inserted consecutively, alternately or once after two windings as per the requirement. In an embodiment, the fibers 20 are inserted consecutively along the whole length of the coiled tube 10 as depicted in FIG. 1. The embolization coil 100 may include 4.00% (w/w) to 5.00% (w/w) while the coiled tube 10 constitutes remaining 95.0% (w/w) to 96.0% (w/w) of the total weight of the embolization coil 100. In an embodiment, the embolization coil 100 includes densely packed fibers 20 which constitute 4.6% (w/w) fiber content and the coiled tube 10 constitutes remaining 95.4% (w/w) of the total weight of the embolization coil 100. The densely packed fibers may increase the surface area of the embolization coil 100 which may lead to an increase in the rate of embolization. The increase in surface area of the embolization coil 100 may reduce the number of coiled tubes 20 to be used at the treatment site. Further, the 4.6% (w/w) fiber content in the embolization coil 100 may cause thrombosis and/or blockage at an implantation site in an adequate time. In an embodiment, the embolization coil 100 results in embolization within a minute of deployment at the treatment site in a patient.
[026] Further, the embolization coil 100 may be self-expanding and/or may acquire a secondary shape to fill the aneurysmal sac at a treatment site. The secondary shape is a shape of the embolization coil after deployment at the treatment site. The secondary shape may include without limitation helical shape, twister shape, diamond shape etc. The aforesaid shapes of the embolization coil 100 may completely fill an inner lumen of the vasculature upon deployment.
[027] In an embodiment, the embolization coil 100 may include an atraumatic tip marker (not shown) at one of the ends. The marker may be made of radiopaque material. The radiopaque material may include without limitation platinum-iridium, platinum-tungsten, platinum, gold, etc. In an embodiment, the marker is made of platinum-iridium. The marker may help to locate the embolization coil 100 in fluoroscopy and/or prevent risk of damage to a vessel wall. The marker may be attached by means of spot -welding technique.
[028] In another embodiment, the embolization coil 100 may be coated with a hydrogel formulation and/or an antifibrinolytic agent. The hydrogel formulation may include without polyvinylalcohol (PVA), polyvinylpyrrolidone (PVP), acrylates, etc. In an embodiment, the hydrogel formulation includes polyethylene glycol and sodium acrylate. The hydrogel formulation may undergo swelling in contact with body fluids and may lead to increase in surface area of the embolization coil 100. The antifibrinolytic agent may include without limitation cyklokapron, aprotinin, tranexamic acid, aminomethylbenzoic acid, etc. In an exemplary embodiment, the antifibrinolytic agent includes aminocaproic acid, tranexamic acid injection, fibrinogen, etc. The antifibrinolytic agent may facilitate blood clotting leading to rapid embolization at the treatment site.
[029] FIG. 2 illustrates a delivery system 200 employed for the embolization coil 100. The delivery system 200 may provide ease in operation, less time consumption and/or prevent the risk of damage to the fibers 20 of the embolization coil 100.
[030] The delivery system 200 may include a loading tube 30, a hub 40, a loading wire 50 and a loader 60. The loading tube 30 may be used to hold the embolization coil 100 during storage and/or may facilitate deployment of the embolization coil 100 using a catheter (not shown). The loading tube 30 may include a distal end 32, a proximal end 34 and a lumen 36 disposed between the proximal end 32 and the distal end 34. The loading tube 30 has an outer diameter in a range of 1 mm-2 mm, wall thickness in a range of 0.10 mm-1 mm and length in a range of 150 mm-250 mm. In an embodiment, the outer diameter is in a range of 1.00 mm-2.00 mm, the wall thickness in a range of 0.15 mm-0.50 mm and length in a range of 200 mm-210 mm. The loading tube 30 may be made of a metallic material. The metallic material may include such as without limitation, the aluminium, brass, copper, stainless steel etc. In an embodiment, the loading tube 30 is made of stainless steel.
[031] Optionally, the loading tube 30 may have a protective sheath (not shown) over an outer surface from the proximal end 32 to the distal end 34 of the tube 30. The protective sheath may be made of polymeric material such as without limitation high-density polyethylene (HDPE), PLGA etc. In an embodiment, the protective sheath is made of high-density polyethylene (HDPE). The diameter of the protective sheath may be in a range of 5.00mm-6.00mm, the wall thickness in a range of 1.00mm-2.00mm and length in a range of 170mm-250mm. In an embodiment, the diameter is in a range of 5.60mm-5.75mm, the wall thickness in a range of 1.15mm-1.30mm and length in a range of 190mm-220mm.
[032] The hub 40 may be attached at the proximal end 34 of the loading tube 30. The hub 40 may be attached by means of without limitation adhesive bonding, ultraviolet gluing technique. The hub 40 may be attached permanently and/or temporarily to the loading tube 30. In an embodiment, the hub 40 is attached by means of ultraviolet gluing. The hub 40 may be made of polymeric material such as without limitation, polycarbonate, acrylonitrile butadiene styrene(ABS), nylon, methacrylate butadiene styrene (MBS). In an embodiment, the hub 40 is made of polycarbonate material. The diameter of an inner lumen of the hub 40 is the same as the diameter of the loading tube 30 that may lead to ease in access of a pusher stylet during deployment of the embolization coil 100.
[033] The loading wire 50 may be detachably placed inside the lumen 36 of the loading tube 30. The loading wire 50 includes a proximal end 52 and a distal end 54. The loading wire 50 may be used to hold the embolization coil 100 in a straight linear configuration and/or facilitate loading of the embolization coil 100 in the loading tube 30. The embolization coil 100 may be placed over the loading wire 50 by means of without limitation micro-forceps, vacuum tweezer, etc. In an embodiment, the embolization coil 100 is placed by means of micro-forceps.
[034] The loading wire 50 may be made of metallic material and their alloys such as without limitation nitinol, copper, aluminium, platinum, platinum-tungsten alloy, etc. In an embodiment, the loading wire 50 is made of stainless steel. The outer diameter of the loading wire 50 may be less than the outer diameter of the embolization coil 100 and the length may be more than the embolization coil 100 in order to adequately support the embolization coil 100 over the loading wire 50. The outer diameter of the loading wire 50 may be in a range of 0.10mm-0.40mm and length may be in the range of 95.0mm-140mm. In an embodiment, the diameter and length are in a range of 0.20mm-0.30mm and 115mm-125mm respectively.
[035] The loader 60 may be detachably placed over the loading wire 50. The loader 60 may facilitate loading of the embolization coil 100 in the loading tube 30. The loader 60 may be made of metallic material and their alloys such as without limitation nitinol, copper, aluminium, platinum, platinum-tungsten alloy, etc. In an embodiment, the loader 60 is made of stainless steel. The diameter of the loader 60 may be in a range of 0.55mm-0.85mm and length may be in the range of 30.0mm-90.0mm. In an embodiment, the diameter and length are in a range of 0.65mm-0.75mm and 50.0mm-70.0mm respectively.
[036] Loading of the embolization coil 100 in the delivery system will now be explained with the help of a flow chart. FIG. 3 illustrates an exemplary process involved in the loading of the embolization coil 100 in the tube 30.
[037] Loading of the embolization coil 100 in the delivery system 200 commences at step 301. At step 301, the lumen 14 of the coiled tube 10 of the embolization coil 100 is placed over the loading wire 50 (as depicted in FIG.4a). The loading wire 50 helps to hold the embolization coil 100 in a straight linear configuration. The coiled tube 10 may be placed over the loading wire 50 with and/or without the fibers 20. In case, the coiled tube 10 (alone) is placed over the loading wire 50, the fibers 20 may be inserted on the loading wire 50. The embolization coil 100 may be placed over the loading wire 50 by means of without limitation micro-forceps, vacuum tweezer etc. In an embodiment, the embolization coil 100 is placed by means of micro-forceps.
[038] At step 303, the loader 60 is manually placed over the loading wire 50 (as shown in FIG.4a). The loader 60 is placed at the proximal end 52 of the loading wire 50 and is pulled towards the distal end 54 of the loading wire 50 until it reaches the embolization coil 100. The loader 60 may facilitate loading of the embolization coil 100 in the tube 30.
[039] At step 305, the loading wire 50 along with the loader 60 is inserted inside the lumen 36 the loading tube 30. The insertion of the loading wire 50 may be done by manual sliding. The insertion may be done at the proximal end 34 of the loading tube 30. The loading wire 50 is pushed towards the distal end of the loading tube 30. The loading wire 50 is pushed in such a way that the embolization coil 100 is partially inside the loading tube 30 as depicted in FIG.4b. Once the embolization coil 100 is partially inside the loading tube 30, the loader 60 is pushed manually towards the distal end 34 of the tube 30. Such movement of the loader 60 triggers complete insertion of the embolization coil 100 inside the loading tube 30 as depicted in FIG.4c.
[040] At step 307, the loading wire 50 is pulled back out of the loading tube 30 from the proximal end 32. Following removal of the loading wire 50, the loader 60 is pulled back ensuring complete loading of the embolization coil 100. The loading tube 30 containing the embolization coil 100 may be stored.
[041] Lastly, as per requirement, the loading tube 30 containing the embolization coil 100 may be deployed at a target site by means of a catheter. The catheter may be of diameter in a range of 3F-6F and length in a range of 90cm-150cm having a guide wire of diameter 0.035 inches. In an embodiment, the diameter of the catheter is 4F.
[042] The invention is now understood by various examples.
[043] Example 1- Embolization coil was fabricated with less than 3% of the fiber. Said embolization coil resulted in delayed embolization, say, more than 1 minute after deployment at the treatment site.
[044] Example 2- Embolization coil was fabricated with more than 5% of the fiber. Said embolization coil resulted in the embolization during delivery, even before implantation at the treatment site. Further, higher amount of the fiber resulted in increase in profile of the embolization coil, which is not compatible with 4F catheter but require catheter having higher diameter. High diameter of the catheter caused trauma to the vessel wall during delivery.
[045] Example 3- Embolization coil is fabricated with 4.6% of the fiber. Said embolization coil results in the embolization within a minute of deployment at the treatment site. Further, the embolization coil is compatible with 4F catheter.
[046] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used.