Claims:WE CLAIM
1. A delivery system assembly comprising:
a flow diverter (100); and
a delivery system (400) configured to deploy the flow diverter (100), the delivery system (400) comprising:
an introducer sheath (401) having a lumen, the introducer sheath (401) including at least one layer;
a delivery wire (403) being placed within the lumen of the introducer sheath (401), the delivery wire (403) including a proximal end and a distal end, the delivery wire (403) having a tapered configuration towards its distal end, the delivery wire (403) being provided with a coil (403a) at the distal end;
a plurality of markers including a proximal marker (407a), a distal marker (407c) and a resheathing marker (407b) disposed therebetween, the proximal marker (407a) disposed towards the proximal end of the delivery wire (403), the distal marker (407c) disposed towards the distal end of the delivery wire (403), wherein the proximal marker (407a) includes an indented structure for providing smooth friction of the proximal marker (407a) against the introducer sheath (401), wherein the resheathing marker (407b) and the distal marker (407c) have a tapered profile which help to maintain the position of the flow diverter (100) during deployment; and
a resheathing pad (405) disposed between the resheathing marker (407b) and the proximal marker (407a) over the delivery wire (403), wherein the resheathing pad (405) is configured to support the flow diverter (100) in crimped state for allowing ease of multiple resheathing thereby resulting in accurate deployment of the flow diverter (100).
2. The delivery system (400) as claimed in claim 1 wherein the delivery system (400) is a guidewire based delivery system.
3. The delivery system (400) as claimed in claim 1 wherein the introducer sheath (401) is made from a material including polytetrafluoroethylene (PTFE), polyimide or the mixture of PTFE-polyimide, polyamide or the mixture of nylon-polyamide, nylon, silicone, polyetheretherketone (PEEK), fluorinated ethylene propylene (FEP), polyether block amide or combination thereof.
4. The delivery system (400) as claimed in claim 1 wherein the introducer sheath (401) is transparent.
5. The delivery system (400) as claimed in claim 1 wherein the dual configuration includes an outer layer (a3) and an inner layer (a2) placed co-axially.
6. The delivery system (400) as claimed in claim 5 wherein the outer layer (a2) and the inner layer (a3) include a braid (a1) there between.
7. The delivery system (400) as claimed in claim 1 wherein the resheathing pad (405) includes one of, a tube or a circular wire coil.
8. The delivery system (400) as claimed in claim 1 wherein the tapered configuration of the delivery wire (403) extends from a pre-defined location till the distal end.
9. The delivery system (400) as claimed in claim 8 wherein the length of the delivery wire (403) from the pre-defined location till the distal end ranges from 550mm to 650mm.
10. The delivery system (400) as claimed in claim 1 wherein the delivery wire (403a) includes a coating of a pre-defined material selected from one or more of teflon, PFA (perfluoroalkoxy alkane), PTFE (polytetrafluoroethylene) and FEP (fluorinated ethylene propylene).
11. The delivery system (400) as claimed in claim 1 wherein the coating includes a thickness ranging from 0.0076mm to 0.0127mm.
12. The delivery system (400) as claimed in claim 1 wherein the coil (403a) includes a J-tip coil.
13. The delivery system (400) as claimed in claim 1 wherein the J-tip coil includes length ranging from 10-20mm.
14. The delivery system (400) as claimed in claim 1 wherein the J-tip coil includes outer diameter ranging from 0.30-0.40mm.
15. The delivery system (400) as claimed in claim 1 wherein the J-tip coil includes inner diameter ranging from 0.18mm to 0.28mm.
16. The delivery system (400) as claimed in claim 1 wherein the delivery system (400) provides a push force of 0.1 N to 1.6 N. ,

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

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

The following complete specification is filed as a Patent of Addition application of the Indian Patent no. 319172 granted on 27th August, 2019.
FIELD OF INVENTION
The present invention relates to a delivery system, more specifically a delivery system for deploying a flow diverter.
BACKGROUND
[001] Intracranial aneurysm refers to a bulge or ballooning in a blood vessel in the brain. Intracranial aneurysm can leak or rupture causing bleeding inside the brain. Intracranial aneurysm occurs in the neurovasculature and is developed at vessel branch points. Aneurysms of anterior neurovasculature can include ICA (Internal Carotid Artery) aneurysms, superior hypophysial artery aneurysms, ophthalmic artery aneurysms, anterior choroidal aneurysms, etc. Aneurysms of posterior neurovasculature can include anterior inferior cerebellar artery (AICA) aneurysms, posterior inferior cerebellar artery (PICA) aneurysms, superior cerebellar artery (SCA) aneurysms, etc.
[002] There are several known methods for the treatment of aneurysms for example, surgical clipping across the artery which feeds the aneurysm, coiling method, flow diversion, etc. The method of flow diversion is safe as compared to other techniques as it does not involve placement of an implant within the aneurysm sac and the method avoids risk associated with coil bulging out of the parent artery. Therefore, this method reduces rupturing of the aneurysm during surgery.
[003] The flow diverters are mostly implanted at the site of aneurysm with the help of a guidewire based delivery system. However, in current procedures, the delivery systems employed for such implants mostly include components which adversely affect the deployment procedure. For example, conventional systems include a holding member which is used to hold the implant while its deployment thereby allowing one end of the flow diverter to be fixed at the target location. Such a holding member however affects the retrieval of delivery system from a microcatheter once the flow diverter is deployed.
[004] Further, the conventional systems have compromised flexibility as well as reduced push force. Further, the conventional systems do not include the provision of multiple resheathing to allow the accurate placement of the flow diverter.
[005] Therefore, there arises a requirement of a delivery device for a flow diverter which overcomes the aforementioned challenges associated with the conventional delivery systems.
SUMMARY
[006] The present invention discloses a flow diverter and its delivery system. The present invention comprises of a flow diverter and a delivery system configured to deploy the flow diverter. The delivery system comprises of an introducer sheath having a lumen, a delivery wire is placed within the lumen of the introducer sheath, a plurality of markers and a resheathing pad. The introducer sheath includes at least one layer.
[007] The delivery wire includes a proximal end and a distal end. The delivery wire is having a tapered configuration towards its distal end. The delivery wire is being provided with a coil at the distal end. The plurality of markers includes a proximal marker, a distal marker and a resheathing marker disposed therebetween. The proximal marker is disposed towards the proximal end of the delivery wire wherein the proximal marker includes an indented structure for providing smooth friction of the proximal marker against the introducer sheath. The distal marker is disposed towards the distal end of the delivery wire, wherein the resheathing marker and the distal marker have a tapered profile which help to maintain the position of the flow diverter during deployment. The resheathing pad disposed between the resheathing marker and the proximal marker over the delivery wire, wherein the resheathing pad is configured to support the flow diverter in crimped state for allowing ease of multiple resheathing thereby resulting in accurate deployment of the flow diverter.
BRIEF DESCRIPTION OF THE DRAWINGS
[008] 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.
[009] FIG.1 depicts a schematic view of the flow diverter in accordance with an embodiment of the present invention.
[0010] FIG.1a depicts a schematic view of one over one braiding pattern in accordance with an embodiment of the present invention.
[0011] FIG.1b depicts a schematic view of two over two braiding pattern in accordance with an embodiment of the present invention.
[0012] FIG.1c depicts a schematic view of one over two braiding pattern design in accordance with an embodiment of the present invention.
[0013] FIG.2 depicts a schematic view of the delivery system of the flow diverter in accordance with an embodiment of the present invention.
[0014] FIG. 2a depicts an alternate embodiment of an introducer sheath in accordance with an embodiment of the present invention.
[0015] FIG. 2b depicts an exemplary embodiment of a proximal marker of the flow diverter in accordance with an embodiment of the present invention.
[0016] FIG. 2c depicts an exemplary embodiment of a resheathing marker of the flow diverter in accordance with an embodiment of the present invention.
[0017] FIG. 2d depicts an exemplary embodiment of a distal marker of the flow diverter in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0018] 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.
[0019] Particular embodiments of the present disclosure are described herein below 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.
[0020] It must be noted that “surface of the flow diverter” in the following description corresponds to inner and outer surfaces of the flow diverter.
[0021] In accordance with the present disclosure, a flow diverter system is disclosed. The flow diverter system includes a flow diverter and a delivery system. The flow diverter of the present invention has uniform wire thickness and braiding angle which provides the flow diverter excellent radial stiffness and crush resistance properties. The flow diverter of the present invention can be used for a number of applications which include without limitation, intracranial, peripheral, carotid, pulmonary, biliary, esophageal, or tapered blood vessels. In an embodiment, the flow diverter is used for the treatment of intracranial aneurysm.
[0022] The flow diverter of the present invention is a braided tube with high strength, high elasticity, high flexibility and reduced pore size. The flow diverter may be braided with one by two braiding pattern which leads to minimal deformation and high recovery during deployment procedure. The reduced pore size of the flow diverter redirects the blood flow in order to restrict the flow of blood inside an aneurysm sac. The reduced pore size of the flow diverter results in greater metal surface area. The reduced pore size also helps in better flow diversion resulting in early formation of an endothelial layer over the metal surface which in turn, enhances the endothelialization process. The flow diverter of the present invention illustrates super elastic behavior.
[0023] The delivery system of the present invention is a guide wire based delivery system. The delivery system includes a plurality of components such as an introducer sheath, a delivery wire, a plurality of markers and a resheathing pad. The introducer sheath is a transparent structure formed by two co-axial tubes. The transparency of the introducer sheath assists an operator to inspect the location of the flow diverter and its configuration within the introducer sheath. Also, the transparency of the introducer sheath helps the operator to confirm the advancement of flow diverter within a microcatheter. The co-axially placed tubes provide flexibility and kink resistance to the introducer sheath.
[0024] The delivery wire includes a coil at its distal end. Such a coil helps in prevention of any possible damage to a vessel wall which may be caused by the tip of the delivery wire during deployment of the flow diverter in tortuous vasculature. The delivery wire of the present invention includes a tapered configuration towards its distal end. Further, a polymer coating is provided over the delivery wire. The tapered configuration of the delivery wire along with the polymer coating renders the delivery wire more flexible and also enhances the lubricity of the delivery wire for ease in movement during deployment through tortuous vasculature.
[0025] The flow diverter is placed over resheathing pad that provides grip to an inner surface of the flow diverter resulting in multiple resheathing. The flow diverter is expanded at the treatment site, by advancing delivery wire into microcatheter.
[0026] The delivery system of the present invention provides a push force of 0.1 N to 1.6 N without any bending, buckling or kinking of the delivery system and the flow diverter.
[0027] FIG. 1 depicts a schematic view of the flow diverter of the present invention. The shape of the flow diverter 100 may be without limitation circular, cylindrical or any shape known in the art. In an embodiment, the flow diverter 100 is cylindrical in shape. As represented, the flow diverter 100 may have without limitation an outer surface 1, an inner surface (not shown), a distal end 3 and a proximal end 5.
[0028] In an embodiment, the flow diverter 100 is fabricated by braiding of one or more ultrathin monofilaments and/or multifilaments (or wires) in a predefined braiding pattern. The multi/monofilaments may be made of, without limitation, a radiopaque (radiopaque wires) and a non-radiopaque material. The radiopaque materials may include without limitation nitinol-platinum, nitinol-platinum alloys, nitinol-titanium alloys, nitinol-tungsten, platinum, platinum tungsten, platinum iridium, stainless steel or combinations thereof. In an embodiment, the radiopaque material is a nitinol-platinum core wire. The nitinol-platinum core wire is used to provide better radiopacity to the flow diverter 100. The nitinol-platinum core wire also enhances elasticity of the flow diverter 100, flexibility of the flow diverter 100 and provides strength to the configuration of the flow diverter 100.
[0029] The nitinol-platinum core wire imparts strength to the flow diverter 100. The nitinol-platinum core wire helps in locating the position of the flow diverter 100 after the implantation of the flow diverter 100 due to its radiopaque property.
[0030] In another embodiment, the platinum-tungsten wire is used for radiopacity to the flow diverter 100. The platinum-tungsten wire is present in the ratio of 92% platinum and 8% tungsten. The platinum-tungsten material is used in such application due to its relatively high degree biocompatibility.
[0031] The diameter of the radiopaque wires may be in the range of 20-50 micron, more preferably 30-40 micron.
[0032] The non-radiopaque materials may include without limitation nitinol, stainless steel, cobalt chromium, cobalt-chromium-tungsten-nickel alloy. In an embodiment, the non-radiopaque material is a nitinol straight annealed wire. In an embodiment, nitinol is selected for the fabrication of the flow diverter 100 as it shows shape memory effect, super elastic behavior, high tensile strength, good corrosion resistance and biocompatibility.
[0033] In an embodiment, the number of radiopaque wires used for the formation of the flow diverter 100 is four and the number of non-radiopaque wires used for the formation of the flow diverter 100 is forty four. The flow diverter 100 is formed in such a way that one radiopaque wire is present in between each set of eleven non-radiopaque wires.
[0034] In another embodiment, the number of radiopaque wires used for the formation of the flow diverter 100 is twelve and the number of non-radiopaque wires used for the formation of the flow diverter 100 is thirty six. The flow diverter 100 is formed in such a way that one radiopaque wire is present in between each set of three non-radiopaque wires.
[0035] In another embodiment, the flow diverter 100 is fabricated from forty eight wires which comprises of forty six non-radiopaque nitinol wires and two radiopaque wires.
[0036] In another embodiment, the flow diverter 100 is fabricated from forty eight wires which comprises of forty two non-radiopaque nitinol wires with six radiopaque wires.
[0037] In another embodiment, the flow diverter 100 is fabricated from forty eight wires which comprises of forty non-radiopaque nitinol wires with eight radiopaque wires.
[0038] In another embodiment, the flow diverter 100 is fabricated from forty eight wires which comprises of thirty eight non-radiopaque nitinol wires with ten radiopaque wires.
[0039] Also, in another embodiment the flow diverter 100 is fabricated only from the radiopaque wire material.
[0040] The braided configuration helps to reroute the blood flow by reducing pore size that restricts penetration of blood inside the aneurysm sac. The braided configuration may have various porosities which are dependent on braiding angle set during braiding process to manufacture the flow diverter 100. In an embodiment, the braiding angle is inversely proportional to the pore size of the flow diverter 100 i.e. as the braiding angles decreases, the pore size of the flow diverter 100 increases which further reduces radial stiffness, integrity and mechanical properties of flow diverter 100. The pore size and the radial stiffness are important parameters which affect the ability of the flow diverter 100 to maintain its integrity and structure after placement of the flow diverter 100 into the body lumen.
[0041] In an embodiment, the flow diverter 100 is formed using one over one braiding pattern (shown in Fig. 1a). The one over one braiding pattern is able to resist distortion to wire spacing. The flow diverter 100 formed using the one over one braiding pattern has a stiffer sidewall.
[0042] In another embodiment, the flow diverter 100 is formed using two over two braiding pattern (shown in Fig. 1b). The two over two braiding pattern is also referred to as the diamond pattern. The two over two braiding pattern is the most flexible braiding pattern in bending stiffness of the flow diverter 100.
[0043] In yet another embodiment, the flow diverter 100 is formed using one over two braiding pattern (shown in Fig. 1c). The one over two braiding pattern is used in the formation of the flow diverter 100 to obtain reduced pore size and high flexibility. The one over two braiding pattern also helps in achieving higher pick counts and small pore sizes. The flow diverter 100 formed using the one over two braiding pattern is less likely to kink when bent around tight radii and provides higher tensile strength or bulb burst strength. The flow diverter 100 formed using one over two braiding pattern has an average pore size in the range of 0.02 to 0.04 mm2.
[0044] In an embodiment, the flow diverter 100 formed using the one over two braiding pattern has braiding angle in the range of 120°-160°, more specifically 125°-155°. The change in the braiding angle can change the axial density of the braid.
[0045] The selection of the braiding angle may also influence the mechanical properties of the flow diverter 100, more specifically, radial strength and crush recovery of the flow diverter 100. The radial strength of the flow diverter 100 defines the strength of the flow diverter 100 to withstand the arterial wall pressure in order to prevent the relocation/migration of the flow diverter 100 from its deployed position. In an embodiment, the radial strength of the flow diverter 100 is approximately in the range of 10-40 N for less than 25mm length flow diverter and above 40N for more than 25mm length of the flow diverter. The crush recovery of the flow diverter 100 defines the self-expanding property of the flow diverter 100. In an embodiment, the flow diverter 100 may have a percentage crush recovery of greater than 95%.
[0046] For example, in a 3.25 mm flow diverter implant having braiding angles between 120° and 160° and made as per braiding process parameters defined above, resulted in radial strength of 10-60 N of the flow diverter implant.
[0047] An exemplary table depicting results of radial strength value obtained relative to the braiding angle of flow diverter braided mesh are shown below:
Opening Braiding Angle (°) Radial Strength value (N)
90-100 No strength
100-110 No strength
120-130 05-30
135-160 10-60

[0048] The above disclosed flow diverter 100 may be manufactured using a pre-defined method as elaborated in Indian patent 319172.
[0049] Fig. 2 depicts the schematic view of the delivery system 400 of the of the flow diverter 100. As represented, the delivery system 400 of the flow diverter 100 includes without limitation an introducer sheath 401, a delivery wire 403, a resheathing pad 405, a one or more markers (or a plurality of markers) 407 and a microcatheter 409.
[0050] The introducer sheath 401 places the flow diverter 100 inside the hollow lumen of the microcatheter 409. The introducer sheath 401 may or may not have, without limitation, a dual layer configuration. In an embodiment, the introducer sheath 401 is a transparent tube comprising of an inner layer and an outer layer.
[0051] The introducer sheath 401 may be made of without limitation a polymeric material. The polymeric material may include, without limitation polytetrafluoroethylene (PTFE), polyimide or the mixture of PTFE-polyimide, polyamide or the mixture of nylon-polyamide, nylon, silicone, polyetheretherketone (PEEK), fluorinated ethylene propylene (FEP), polyether block amide, etc.
[0052] In an embodiment, the inner layer of the introducer sheath 401 is composed of polyimide-PTFE blend or polytetrafluoroethylene (PTFE). The outer layer of the introducer sheath 401 is composed of polyimide and/or nylon material. The polyimide used for the formation of the outer layer of the introducer sheath 401 provides strength and integrity to the introducer sheath 401. The polyimide used also helps to prevent the deformation and kinking of the introducer sheath 401 during the deployment process. The utilization of PTFE for the inner tube provides smoothness to the introducer sheath 401 and eliminates friction between the introducer sheath 401 and the delivery wire 403. The utilization of nylon for the outer tube provides strength and integrity to the introducer sheath 401 thereby preventing its deformation and kinking during deployment process. The wall thickness of the inner tube may range from 0.01mm to 0.03mm. In an embodiment, the wall thickness of the inner tube is 0.02mm. The wall thickness of the outer tube may range from 0.10mm to 0.15mm. In an embodiment, the wall thickness of the outer tube is 0.115mm.
[0053] In another embodiment of the present invention, a braid a1 is provided between the inner and outer tubes a2, a3 as shown in FIG. 2a. The braid a1 may be made of a plurality of wires. The braid a1 may be formed via multiple wires in a range of 4 to 32. In an embodiment, 16 wires are used to form the braid a1.
[0054] The wires may be made of pre-defined material(s) including, without limitation, stainless steel, nitinol or cobalt chromium. The wires may be flat, round, etc. In an embodiment, stainless steel flat wires are used to make the braid owing to their higher strength. In the said embodiment, the outer tube a3 is made of polyimide while the inner tube a2 is composed of polyimide-PTFE blend. The utilization of polyimide in making of the introducer sheath 401 provides strength and integrity to the introducer sheath 401 thereby preventing its deformation and kinking during deployment process.
[0055] The transparency of the introducer sheath 401 helps to inspect the location of the flow diverter 100 and the configuration of the flow diverter 100 within the introducer sheath 401. The transparency of the introducer sheath 401 also helps to confirm the advancement of the flow diverter 100 within the proximal end of the microcatheter 409. Also, the transparency helps to identify that the flow diverter 100 maintains its structure without any twisting or damage.
[0056] In an embodiment, the lumen diameter of the introducer sheath 401 may be in the range of 0.40-0.70mm, more preferably 0.55-0.65mm. In an embodiment, the inner lumen diameter is 0.58mm. The outer lumen diameter of introducer sheath 401 may range between 0.65mm to 1.0mm. In an embodiment, the outer lumen diameter is 0.85mm. The introducer sheath 401 may have a wall thickness in the range of 0.05-0.20mm. In an embodiment, the wall thickness of the introducer sheath 401 is 0.135mm. The wall thickness of the inner tube may range between 0.01mm to 0.03mm. In an embodiment, the wall thickness of the inner tube is 0.02mm. The wall thickness of the outer tube may range between 0.10mm to 0.15mm. In an embodiment, the wall thickness of the outer tube is 0.115mm.
[0057] The introducer sheath 401 may have a length in the range of 50-100cm, more preferably 60-80cm. In an embodiment, the length of the introducer sheath 401 is 70cm. The outer diameter of the introducer sheath 401 is lesser than the inner diameter of microcatheter for ease in access through the microcatheter during deployment of flow diverter. In an embodiment, the introducer sheath 401 as explained above may be compatible with a standard microcatheter of 2.4Fr – 2.7Fr during deployment of the flow diverter 100.
[0058] The delivery wire 403 may include a pre-defined length. The length of the delivery wire 403 may be in a range of 1800mm to 2000mm. In an embodiment, the length of the delivery wire 403 is 1900mm.
[0059] The delivery wire 403 may include without limitation, a distal end (not shown), a proximal end (not shown) and a coil 403a. The delivery wire 403 is placed inside the hollow lumen of the introducer sheath 401. The delivery wire 403 is coupled to the resheathing pad 405 and the one or more markers 407 (distal marker, resheathing marker, proximal marker). The flow diverter 100 is placed over the delivery wire 403. The delivery wire 403 carries the flow diverter 100 which is placed inside the introducer sheath 401 and other components of the delivery system 400 to the hollow lumen of the microcatheter 409.
[0060] In an embodiment, the delivery wire 403 is of tapered configuration. The delivery wire 403 may have a constant diameter from the proximal end till a pre-defined location and gradually tapers from the pre-defined location till the distal end of the delivery wire 403 (tapered portion). The length of the delivery wire 403 from the proximal end to the pre-defined location may range between 1250mm to 1350mm. In an embodiment, the length is 1300mm. The constant diameter may lie in a range of 0.40mm to 0.50mm. In an embodiment, the constant diameter is 0.45mm. The length of the tapered portion may range between 550mm to 650mm. In an embodiment, the length of the tapered portion is 600mm. The diameter of the pre-defined location may lie in a range of 0.40mm to 0.50mm. In an embodiment, the diameter of the pre-defined location is 0.45mm. The diameter of the distal end may lie in a range of 0.02mm to 0.12mm. In an embodiment, the diameter of the distal end is 0.092mm.
[0061] Such tapering allows the physician to smoothly navigate the delivery system 400 through the tortuous vessel anatomy of intracranial pathway without any damage to the vessel lumen. Also, the tapered delivery wire 403 helps in maintaining the flexibility and crimp profile of the flow diverter 100.
[0062] The delivery wire 403 may be made of without limitation, nitinol or platinum-tungsten or stainless steel material. In an embodiment, the delivery wire 403 is made of 304V stainless steel material.
[0063] In an embodiment, the delivery wire 403 includes two visual markers at proximal end (not shown) of delivery wire 403. The visual markers guide to deliver the flow diverter 100 which is placed inside the introducer sheath 401 and other components of the delivery system 400 to the hollow lumen of the microcatheter 409. The length of the microcatheter 409 decides the position of the visual markers on proximal end of the delivery wire 403. The position of the visual markers may also depend upon the length of the crimped flow diverter 100.
[0064] Out of the two markers, a first visual marker is emplacing at 330-370mm distance from the proximal end of delivery wire. The second visual marker is emplacing at 530-570mm distance from the proximal end of the delivery wire 403.
[0065] In an embodiment, the first visual marker reaches at the microcatheter hub indicates that coil tip of the delivery wire 403 has reached at the microcatheter tip end. The second visual marker reaches at microcatheter hub indicates the flow diverter 100 is completely deployed from the microcatheter 409.
[0066] In an embodiment, the delivery wire 403 has a tapered configuration. The delivery wire 403 may be provided with a coating. The said coating may be provided over the entire surface of the delivery wire 403 or may cover a particular portion of the delivery wire 403. In an embodiment, the portion of the delivery wire 403 extending till 1760mm to 1780mm from the proximal end may be coated. The coating may be a polymer coating of at least one pre-defined material. The pre-defined materials may include, without limitation, teflon, PFA (perfluoroalkoxy alkane), PTFE (polytetrafluoroethylene), FEP (fluorinated ethylene propylene) etc. In an embodiment, the polymer coating is made of PTFE. The coating may have a thickness ranging from 0.0076mm to 0.0127mm. The tapered configuration of the delivery wire 403 along with the PTFE coating over the delivery wire 403 enhances the lubricity and makes the delivery wire 403 more flexible for easy movement during deployment through tortuous vasculature.
[0067] The delivery wire 403 may include without limitation, a coil 403a. In an embodiment, the delivery wire 403 has a J-tip coil. The J-tip coil is coupled at the distal end of the delivery wire 403. The J-tip coil is made of without limitation, platinum-tungsten material, gold, nitinol, cobalt chromium, stainless steel or any alloy combination thereof. In an embodiment, the coil is made of platinum-tungsten material.
[0068] In an embodiment, the outer diameter of the J-tip coil may range from 0.30-0.40mm, more preferably 0.34-0.38mm. In an embodiment, the outer diameter is 0.36mm. The coil 403a may have an inner diameter ranging from 0.18mm to 0.28mm. In an embodiment, the inner diameter is 0.24mm.
[0069] The length of the J-tip coil may range from 10-20mm. In an embodiment, the length of the coil 403a is 15mm. The J-tip coil has a bending configuration that helps to prevent the damage of the vessel wall by the tip of the delivery wire 403 during deployment of the flow diverter 100 in tortuous vasculature.
[0070] The coil 403a may be formed from a round wire having diameter of 0.02mm to 0.10mm. In an embodiment, the wire diameter is 0.06mm. The coil 403a includes a pitch size which may be same as the wire diameter.
[0071] The coil 403a may include two ends. One end of the coil 403a may be attached to the delivery wire 403 while the other end 403a1 may be a semispherical or dome shaped structure. The end 403a1 may include a radius of 0.10mm to 0.30mm. In an embodiment the radius of the end 403a1 is 0.20mm.
[0072] Such an end helps to prevent any damage to vessel wall during deployment of the flow diverter 100 through tortuous vasculature. Hence, the coil 403a acts as an atraumatic tip of the delivery wire 403.
[0073] The resheathing pad 405 may include without limitation, a proximal and a distal end (not shown). The resheathing pad 405 is coupled to the delivery wire 403. The length of the resheathing pad 405 may range from about 1-5mm, more preferably 2-4mm.
[0074] In an embodiment, the resheathing pad 405 is a tube that includes an outer layer and an inner layer (not shown). The outer layer may be made of without limitation silicone, rubber, thermoplastic polyurethane, poly-ether block amide or pebax. In an embodiment, the outer layer is made of silicone or pebax material. The silicone material maintains strong longitudinal grip with the inner layer of the flow diverter 100 that helps in ease of multiple resheathing of the flow diverter 100 during the deployment procedure. The diameter of the outer layer may range from 0.30-0.60 mm and the thickness of the outer layer may range from 0.050 to 0.105mm, more preferably from 0.070 to 0.100mm. In an embodiment, the diameter of the outer layer is 0.46mm and the thickness of the outer layer is 0.095mm. The thickness of the outer layer of the resheathing pad 405 may be dependent upon the inner diameter of the resheathing pad 405. The inner diameter of the outer layer may range between 0.19mm to 0.35mm. In an embodiment, the inner diameter of the outer layer is 0.27mm.
[0075] The inner layer may be made of without limitation, polyimide tube, nylon, pebax, and polyamide. In an embodiment, the inner layer is made of nylon or pebax material. The nylon or pebax material provides support and rigidity to the inner layer of the flow diverter 100 which helps to avoid the deformation of the resheathing pad 405 during movement through the tortuous vasculature. The diameter of the inner layer may range from 0.20-0.30 mm, more preferably about less than or equal to 0.27 mm and the thickness of the inner layer may range from 0.020-0.050mm, more preferably 0.035-0.045mm. In an embodiment, the thickness of the inner layer is 0.04mm. As the inner diameter of the resheathing pad 405 changes, the thickness of the outer layer is changed. The inner diameter of the inner layer corresponds to the inner diameter of the resheathing pad 405. The inner diameter of the resheathing pad 405 may range from 0.11mm to 0.27mm. In an embodiment, the inner diameter of the resheathing pad 405 is 0.19mm.
[0076] The inner tube may be harder than the outer layer. Such hardness of the inner tube provides support and rigidity to the resheathing pad 405 which in turn helps to prevent deformation of the resheathing pad 405 during navigation of the delivery system 400 through tortuous vasculature.
[0077] In another embodiment, resheathing pad 405 is a circular wire coil. The coil may be made of without limitation of nitinol, platinum, nitinol-platinum core wire and platinum tungsten wire. In an embodiment, the coil is made up of platinum-tungsten material. The diameter of coil may range from 0.25-0.35mm. In an embodiment, the outer diameter is 0.31mm. The coil may have a length ranging from 1.0mm to 5.0mm. In an embodiment, the length of the coil is 3.0mm. The coil may have an inner diameter ranging from 0.16mm to 0.25mm. In an embodiment, the inner diameter is 0.21mm.
[0078] The coil may be formed with the help of a wire. In an embodiment, the wire is round in shape having a diameter of 0.01mm to 0.08mm. In an embodiment, the diameter of the wire is 0.02mm to 0.06mm. The coil may include a pitch size same as the wire diameter.
[0079] The one or more markers 407 may include without limitation, a distal marker 407c, resheathing marker 407b and a proximal marker 407a. The one or more markers 407 may be placed without limitation along the proximal and distal ends of the resheathing pad 405. The one or more markers 407 may be made of without limitation, stainless steel, platinum-iridium, platinum tungsten material, more preferably from platinum iridium material. In an embodiment, the one or more markers 407 are made of platinum-iridium material. The iridium material in combination with platinum material provides strength to the one or more markers and also aids in radiopacity of the one or more markers 407 under a fluoroscopic examination.
[0080] In an embodiment, the proximal marker 407a is present at the proximal end of the resheathing pad 405. The proximal marker 407a has an outer diameter in the range of 0.50-0.60mm, more preferably 0.54-0.58mm and inner diameter ranging from 0.18-0.23mm. The tapered diameter of the proximal marker 407a may range from 0.30-0.40mm. The proximal marker 407a may have a length ranging from 1mm to 5mm. In an embodiment, the length of the proximal marker 407a is 2.10mm.
[0081] The flow diverter 100 is mounted between the proximal marker 407a and the distal marker 407c in crimped state. The proximal marker 407a acts as a pusher by pushing forward the flow diverter 100 towards a distal end of the microcatheter 409 during deployment process into the body lumen. The proximal marker 407a also helps to define the total crimped length of the flow diverter 100 and assists in locating the flow diverter’s (100) position during the deployment process.
[0082] FIG. 2b depicts an exemplary embodiment of the proximal marker 407a which includes a proximal end 407a1 and a distal end 407a2 placed opposite to the proximal end 407a1. The proximal end 407a1 of the proximal marker 407a is so positioned that the distal end 407a2 faces the flow diverter 100. The proximal marker 407a may be an indented structure having a proximal portion 407’, a mid portion 407” and a distal portion 407’”. The proximal portion 407’ is disposed at the proximal end 407a1 while the distal portion 407”’ is disposed at the distal end 407a2 of the proximal marker 407a. The mid portion 407” between the proximal portion 407’ and the distal portion 407'” of the proximal marker 407a may have a fillet corner. The mid portion 407” provides smooth friction against the introducer sheath 401.
[0083] The proximal portion 407’ may include an outer diameter in a range of 0.30mm to 0.40mm. In an embodiment, the outer diameter of proximal portion 407' is 0.35mm. Likewise, the distal portion 407”’ includes an outer diameter in a range of 0.50mm to 0.60mm. In an embodiment, the outer diameter of the distal portion 407”’ is 0.56mm.The mid portion 407” may have a radius ranging from 0.01mm to 0.20mm. In an embodiment, the radius is 0.10mm.
[0084] The diameter of the flow diverter 100 decides its in-sheath loaded length and the flow diverter 100 ultimately affects the position of the proximal marker. The change in position of the proximal marker largely affects its internal diameter because of the tapered delivery configuration of the delivery wire 403 that leads to a change in the internal diameter of the proximal marker.
[0085] In an embodiment, the resheathing marker 407b is present at the distal end of resheathing pad. The resheathing marker 407b has an outer diameter in the range of 0.40-0.52mm, more preferably 0.44-0.48mm and inner diameter ranging from 0.15-0.23mm. In an embodiment, the inner diameter is 0.19mm. The tapered diameter of the resheathing marker 407b may range from 0.28-0.35mm. The length of the resheathing marker 407b may lie in a range of 0.5mm to 2mm. In an embodiment, the length of the resheathing marker 407b is 1.0mm.
[0086] FIG. 2c represents an exemplary embodiment of a resheathing marker 407b which includes a proximal end 407b1 and a distal end 407b2 placed opposite to the proximal end 407b1. The resheathing marker 407b is so placed that the proximal end 407b1 faces the resheathing pad 405. The resheathing marker 407b may be tapered with the proximal end 407b1 having a diameter more than the distal end 407b2. The diameter of the proximal end 407b1 may range from 0.40mm to 0.52mm. In an embodiment, the diameter of the proximal end 407b1 is 0.46mm. The diameter of the distal end 407b2 may range from 0.20mm to 0.40mm. In an embodiment, the diameter of the distal end 407b2 is 0.31mm.
[0087] The resheathing marker 407b acts as an indicator to repositioning the flow diverter 100 towards a proximal end of the microcatheter during deployment process into the body lumen.
[0088] In an embodiment, the distal marker is present at junction of the delivery wire 403 and J-tip coil. The distal marker has an outer diameter in the range of 0.40-0.50mm, more preferably in between 0.45-0.50mm and inner diameter in the range of 0.05-0.15mm, more preferably 0.08-0.12mm. In an embodiment, the diameter of the lumen is 0.10mm. The length of the distal marker is in a range of 0.5mm to 2mm. In an embodiment, the length of the distal marker is 1.0mm.
[0089] The distal marker 407c helps to position the flow diverter 100 during the deployment process at the aneurysm neck. The distal marker 407c helps to define the total crimped length of the flow diverter 100.
[0090] An exemplary embodiment of the distal marker is shown in FIG. 2d and marked as distal marker 407c. The distal marker 407c includes a proximal end 407c1 and a distal end 407c2 placed opposite to the proximal end 407c1. Like the structure of the resheathing marker 407b, the distal marker 407c may also be tapered. As shown in FIG. 2d, the proximal end 407c1 includes a diameter which is less than the diameter of the distal end 407c2. The diameter of the proximal end 407c1 may range from 0.20mm to 0.40mm. In an embodiment, the diameter of the proximal end 407c1 is 0.31mm.The diameter of distal end 407c2 may range from 0.40mm to 0.52mm. In an embodiment, the diameter of the distal end 407c2 is 0.46mm. Such tapered profile of the distal marker 407c helps to maintain the position of the flow diverter 100 during the deployment process i.e. flow diverter 100 is placed between proximal marker 407a and distal marker 407c.
[0091] The microcatheter 409 is used to deliver the flow diverter 100 in an intracranial vessel. The delivery system 400 of the flow diverter 100 may be compatible with a 2.4-2.7F microcatheter with a length of 100-150cm. In an embodiment, the delivery system 400 of the flow diverter 100 is compatible with the microcatheter 409 which contains a guide wire having 0.014”-0.027” size and length of 190-195cm.
[0092] The above described delivery system 400 is operated in a pre-defined manner. Once the microcatheter 409 reaches the target site, the delivery system 400 is placed at the hemostatic hub of the microcatheter 409. The distal portion of the introducer sheath 401 is placed at the hemostatic hub and a haemostatic valve is tightened to fix the position of the introducer sheath 401. The distal portion of the introducer sheath 401 is placed inside a hub of microcatheter 409 for smooth transfer of the delivery system 400.
[0093] The delivery wire 403 is slowly pushed towards the distal part of the microcatheter 409. Owing to the transparency of the introducer sheath 401, the movements of the flow diverter 100 may be visualized. Further, the movement of the delivery wire 403 may be determined on the basis of visual marker provided on the delivery wire 403.
[0094] Once the coil 403a of the delivery system 400 reaches the distal end of the microcatheter 409, the distal end of microcatheter 409 is adjusted. The delivery wire 403 is then slowly pushed and the microcatheter 409 is simultaneously retracted to deploy the flow diverter 100. The proximal marker 407a and distal marker 407c help to locate the position of the flow diverter 100 during deployment.
[0095] In cases where the flow diverter 100 is incorrectly deployed, resheathing of the flow diverter 100 may be done. The resheathing limit is decided based upon the resheathing marker 407b as the location of the resheathing marker 407b helps to determine whether resheathing of the flow diverter 100 is possible or not. For example, the exposure of the resheathing marker 407b from the microcatheter lumen serves as an indication for the operator that the resheathing of the flow diverter 100 is not possible.
[0096] Subsequently, the delivery wire 403 is pushed till the second visual marker and the flow diverter 100 is fully deployed inside an intracranial artery.
[0097] The present invention may be supported by the following examples:
Example 1:
[0098] A guidewire based delivery system ‘A’ was used to deliver a flow diverter in an intracranial artery. The system ‘A’ included a tapered delivery wire with a proximal bumper, one or more markers, an introducer sheath, a self-expanding flow diverter and a holding member to deliver the flow diverter in an intracranial artery containing aneurysm. A delivery system “A” having a holding member was disposed on a distal end of the delivery wire. The length of the holding member was 2.5 mm. The holding member was in the form of a polymeric tube and was used for holding the distal part of flow diverter during the deployment process. The holding member was cut from the center and divided in two parts to generate a clamp-like structure.
[0099] It was observed that once the flow diverter was expanded and the delivery system was retracted, the holding member could not attain a proper position. Due to this, there was disturbance in retracting the delivery wire as it was struck in the lumen. The physician had to remove the delivery wire and microcatheter causing vessel damage.
Example 2:
[00100] A guidewire based delivery system ‘B’ having a tapered delivery wire (with a polymer coating), a proximal marker, a distal marker, a resheathing marker as well as a dual layered and transparent introducer sheath was used to deliver a self-expanding flow diverter in an intracranial artery containing aneurysm. The proximal marker of the delivery system ‘B’ included an indented structure while the resheathing marker and the distal marker included tapered configurations. The overall profile of the delivery system ‘B’ was compatible with the profile of the microcatheter lumen.
[00101] It was observed that owing to the structure and positioning of the distal marker and proximal marker, there was no damage found to the flow diverter. Further, the delivery system was easily retracted from the microcatheter without any trouble. Further, owing to the transparency of the introducer sheath, the location of the flow diverter was easy to trace. Also, the delivery system was found to easily navigate through the tortuous vasculature due to the polymer coating and the tapered configuration of the delivery wire.
[00102] 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.