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

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 a medical device. More specifically, the present invention relates to an outer sheath for an endovascular procedure.
BACKGROUND OF INVENTION
[002] An endovascular procedure involves the use of a catheter to treat various conditions affecting the heart and blood vessels. The catheter typically includes an outer sheath and multiple internal lumens, each designed to facilitate different functions during the procedure.
[003] Since blood vessels have a complex geometry including various curves, bends, and/or turns, the catheter experiences significant mechanical stress while being navigated inside a body lumen, especially, at the curves and bends of the blood vessels. If the mechanical stress is high, the catheter may kink. The kinking of the outer sheath may result in formation of a sharp bend or at least one pointed end at the bend of the outer sheath. This may impend smooth advancement of the catheter and even cause damage to an inner wall or adjacent tissue of the blood vessel.
[004] Further, the outer sheath may have a very large diameter. Due to which the outer sheath may sit tight against the walls of the blood vessel during the navigation of the catheter within the blood vessel. This causes friction between the walls and the outer sheath. Due to higher friction, there is an increased chance of damage to the walls and the surrounding tissues.
[005] Therefore, there is a need of an outer sheath that can overcome the problems associated with the conventionally outer sheath.
SUMMARY OF INVENTION
[006] The present disclosure relates to an outer sheath including a distal portion, a middle portion and a proximal portion. The middle portion couples the distal portion and the proximal portion. The distal portion has a first diameter and the proximal portion has a second diameter. The first diameter is greater than the second diameter.
[007] The present disclosure also relates to an outer sheath including a distal portion and a proximal portion. The proximal portion is coupled to the distal portion. In an embodiment, the distal portion includes a coil and the proximal portion is braided.
[008] The foregoing features and other features as well as the advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
BRIEF DESCRIPTION OF DRAWINGS
[009] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the apportioned 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.
[0010] Fig. 1 depicts a perspective view of an outer sheath 100 in accordance with an embodiment of the present invention.
[0011] Fig. 2 depicts a perspective view of a distal portion 110 of the outer sheath 100, in accordance with an embodiment of the present disclosure.
[0012] Fig. 2a depicts an enlarged view of the distal portion 110 showing a coil 115, in accordance with an embodiment of the present disclosure.
[0013] Fig. 2b depicts an axial cross-section of the distal portion 110, in accordance with an embodiment of the present disclosure.
[0014] Fig. 3 depicts a perspective view of a proximal portion 130 of the outer sheath 100, in accordance with an embodiment of the present disclosure.
[0015] Fig. 3a depicts an enlarged view of the proximal portion 130, in accordance with an embodiment of the present disclosure.
[0016] Fig. 3b depicts an axial cross-sectional view of the proximal portion 130, in accordance with an embodiment of the present disclosure.
[0017] Fig. 4 depicts side view of a middle portion 150 of the outer sheath 100, in accordance with an embodiment of the present disclosure.
[0018] Fig. 5 depicts a flow chart of an exemplary method 500 for manufacturing the outer sheath 100, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0019] 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.
[0020] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
[0021] Although the operations of exemplary embodiments of the disclosed method may be described in a particular, sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular, sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment, and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses.
[0022] Furthermore, the described features, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments. These features and advantages of the embodiments will become more fully apparent from the following description and apportioned claims, or may be learned by the practice of embodiments as set forth hereinafter.
[0023] In accordance with the present disclosure, an outer sheath for an endovascular procedure is disclosed. The outer sheath includes a plurality of portions having varied diameter. For example, a distal portion of the outer sheath has a larger diameter compared to the diameter of a proximal portion. The larger diameter of the distal portion of the outer sheath provides a clearance between the proximal portion of the outer sheath and the inner walls of the blood vessel. The distal portion of the outer sheath dilates the blood vessel allowing the proximal portion of the outer sheath to be navigated easily within the blood vessel. Thus, reducing the friction between the inner walls and the outer sheath. In an embodiment, the distal portion of the outer sheath is provided with a metallic coil. The metallic coil reinforces the distal portion and allows the distal portion of the outer sheath to navigate through complex geometries of the blood vessel, without kinking. This reduces the chances of the damage to the blood vessel caused due to the kinking of the outer sheath.
[0024] Fig. 1 depicts a perspective view of an outer sheath 100, according to an embodiment of the present disclosure. The outer sheath 100 has an elongated, tubular structure, defining a central lumen. In an embodiment, the outer sheath 100 may correspond to an outermost tube of a catheter (not shown). In an embodiment, the outer sheath 100 may be an introducer sheath for an endovascular procedure. The outer sheath 100 has a proximal end 100a and a distal end 100b. In an embodiment, the outer sheath 100 includes two or more segments of varying diameter along its length, defining a plurality of portions. Each portion of the plurality of portions of the outer sheath 100 has a corresponding length and diameter. The combined length of the plurality of portions corresponds to the length of the outer sheath 100. In an embodiment, the outer sheath 100 has a distal portion 110, a proximal portion 130, and a middle portion 150.
[0025] Referring to Fig. 2, the distal portion 110 is disposed towards the distal end 100b of the outer sheath 100. The distal portion 110 may be configured to accommodate a stent graft or device (not shown) to be deployed in a blood vessel of a target site. In an embodiment, the distal portion 110 is configured to accommodate a stent graft. The stent graft remains in a crimped state (or radially compressed state) within the distal portion 110 of the outer sheath 100 during navigation. The length of the distal portion 110 of the outer sheath 100 may be greater than or equal to the length of the stent graft. In an embodiment, the length of the distal portion 110 of the outer sheath 100 is equal to the length of the stent graft such that the stent graft does not move within the distal portion 110, thereby avoiding any relative motion between the stent graft and the outer sheath 100 during the navigation of the catheter within the vasculature of a patient. The dimensions of the distal portion 110 may be chosen according to the application for which the outer sheath 100 is used. In an embodiment, the distal portion 110 has a first diameter. The first diameter corresponds to an outer diameter of the distal portion 110. The first diameter of the distal portion 110 may range between 6 mm and 8.5 mm. In an embodiment, the first diameter is 8 mm. The inner diameter of the distal portion 110 may correspond to an outer diameter of the stent graft in the crimped state. The inner diameter of the distal portion 110 may range between 5.30 mm and 7.9 mm. In an embodiment, the inner diameter of the distal portion 110 is 7.2 mm.
[0026] In an embodiment the distal portion 110 includes a tip 117 provided at the distal end 100b of the outer sheath 100. The tip 117 may be provided with a radiopaque coating of a material including, but not limited to, barium sulfate (BaSO4), bismuth, tungsten, etc. In an embodiment, the tip 117 is coated with BaSO4. The radiopaque coating enhances the visibility of the tip 117 during the navigation through the vasculature of a patient, under an imaging system such as X-rays or fluoroscopy, etc. This makes it easier to navigate the outer sheath 100 to a target site. The tip 117 has a hollow tubular structure. The tip 117 may be tapered at an angle with respect to a longitudinal axis of the outer sheath 100. The angle my range from 4° to 7°. In an embodiment, the tip 117 is tapered at an angle of 5°. A tapered shape of the tip 117 facilitates easy navigation, and reduces the chances of damage to the walls of the blood vessel during the navigation of the outer sheath 100 to the target site.
[0027] Fig. 2b depicts an axial cross-section of the distal portion 110. The distal portion 110 may include two or more layers. In an embodiment, the distal portion 110 includes two layers - an inner layer 111, and an outer layer 113. In an embodiment, the inner layer 111 corresponds to an inner-most layer of the distal portion 110. The inner layer 111 may have a smooth inner surface to reduce friction between the stent graft and the inner surface of distal portion 110, during its deployment at the target site. The inner layer 111 may be made of a biocompatible polymeric material including, but not limited to, polytetrafluoroethylene (PTFE), polyether ether ketone (PEEK), polyether block amide (PEBAX), etc. In an embodiment, the inner layer 111 is made of PTFE. The inner layer 111 may have a thickness ranging from 0.003 mm to 0.007 mm. In embodiment, the inner layer 111 has a thickness of 0.005 mm.
[0028] The outer layer 113 is disposed outside the inner layer 111. The outer layer 113 may concentric with the inner layer 111. In an embodiment, the outer layer 113 corresponds to an outer-most layer of the distal portion 110. The outer layer 113 may be made of a biocompatible, polymeric material configured to reduce the friction between the distal portion 110 and the walls of the blood vessels during the navigation of the outer sheath 100 through the vasculature of the patient, to the target site. The outer layer 113 may be made of a material including, but not limited to, polyurethane (PU), PEEK, PTFE, PEBAX, etc. In an embodiment, the outer layer 113 is made of PEBAX. The thickness of the outer layer 113 may range between 0.04 mm and 0.09 mm. In an embodiment, the thickness of the outer layer 113 is 0.05 mm.
[0029] In an embodiment, the distal portion 110 includes at least one coil 115. For example, the distal portion 110 may include one coil 115 (shown in Fig. 2a). The coil 115 has an inner surface and an outer surface. The coil 115 is provided between the outer layer 113 and the inner layer 111 of the distal portion 110 such that the inner layer 111 is coupled to the inner surface of the coil 115 and the outer layer 113 is coupled to the outer surface of the coil 115. The inner layer 111 and the outer layer 113 are coupled to the coil 115 using a coupling method, such as, without limitation, adhesive bonding, heat shrinking, ultrasonic bonding, crimping etc. In an embodiment, the inner layer 111, the outer layers 113 are coupled with the coil 115 using heat shrinking. The coil 115 prevents the distal portion 110 from kinking by providing radial strength to the distal portion 110 to withstand the stress developed during the navigation through the curves of the blood vessels. The coil 115 may extend at least partially for a length of the distal portion 110. In an embodiment, the coil 115 extends along the entire length of the distal portion 110. In an embodiment, the coil 115 is made of a wire having a circular cross-section, though it is possible that the wire may have any other cross-section. The coil 115 may be made of a material including, but not limited to, nitinol, stainless steel (e.g., SS314, SS304), and so forth. In an embodiment, the coil 115 is made of SS304. The coil 115 may have a predefined pitch, ranging between 0.3 mm to 0.8 mm. In an embodiment, the pitch of the coil 115 is 0.6 mm. The diameter of the coil 115 may range between 5.25 mm and 7.25 mm. In an exemplary embodiment, the diameter of the coil 115 is 7.23 mm. The diameter of the wire used for making the coil 115 may range between 0.1 mm and 0.7 mm. In an example implementation, the diameter of the wire is 0.55 mm.
[0030] Although the inner layer 111, the outer layer 113 and the coil 115 are explained separately, the inner layer 111, the outer layer 113, and the coil 115 may be fused into a single integral structure through a heating process thereby, forming the distal portion 110 of the outer sheath 100.
[0031] Optionally, the distal portion 110 may include one or more additional layers provided inside the inner layer 111 and/or outside the outer layer 113.
[0032] Fig. 3 depicts a section of the proximal portion 130, in accordance with an embodiment of the present disclosure. The proximal portion 130 is disposed towards the proximal end 100a of the outer sheath 100 and is coupled to the distal portion 110. In an embodiment, the proximal portion 130 and the distal portion 110 are coupled using the middle portion 150. In another embodiment, the proximal portion 130 and the distal portion 110 are coupled directly. The length of the proximal portion 130 may be chosen based on the clinical requirement. In an embodiment, the length of the proximal portion 130 may range between 700 mm and 750 mm. In an exemplary embodiment, the length of the proximal portion 130 is 710 mm.
[0033] In an embodiment, the proximal portion 130 has a second diameter. The second diameter of the proximal portion 130 corresponds to an outer diameter of the proximal portion 130. The second diameter of the proximal portion 130 is smaller than the first diameter of the distal portion 110 i.e., the first diameter is greater than the second diameter. Such a design provides a clearance between the proximal portion 130 and the inner wall of the blood vessel, ensuring that at least partial length of the proximal portion 130 does not make any contact with the inner wall of the blood vessel. Thus, the friction between the outer sheath 100 and the inner wall of the blood vessel is minimized. The reduced friction between the vessels and the outer sheath 100, minimizes the chances of damage to the tissues of the inner wall of the blood vessel.
[0034] The second diameter of the proximal portion 130 may range between 5 mm and 7 mm. In an embodiment, outer diameter of the proximal portion 130 is 5.9 mm. The inner diameter of the proximal portion 130 may range between 4.7 mm and 6 mm. In an embodiment, the inner diameter of the proximal portion 130 is 5.3 mm.
[0035] Fig. 3b depicts an axial cross-section of the proximal portion 130. The proximal portion 130 may include two or more layers. The proximal portion 130 is braided. For example, the proximal portion 130 may include at least one braided layer. In an embodiment, the proximal portion 130 includes three layers - a first layer 131, a second layer 133 and a braided layer 135.
[0036] In an embodiment, the first layer 131 corresponds to the outermost layer of the proximal portion 130. The first layer 131 may be made of a biocompatible polymeric material including, but not limited to, PTFE, PEEK, PU, PEBAX, (polyamide) PA, VESTAMID®, etc. In an embodiment, the first layer 131 is made of VESTAMID®. The first layer 131 may have a thickness ranging from 0.004 mm to 0.009 mm. In an embodiment, the thickness of the first layer 131 is 0.005 mm.
[0037] The first layer 131 is disposed outside the second layer 133. In an embodiment, the second layer 133 corresponds to the innermost layer of the proximal portion 130. The second layer 133 may be made of a material including, but not limited to, PTFE, PEEK, PU, PEBAX, etc. In an embodiment, the second layer 133 is made of PTFE. The second layer 133 may have a thickness ranging from 0.003 mm to 0.007 mm. In an embodiment, the thickness of the second layer 133 is 0.005 mm.
[0038] The braided layer 135 has an inner surface and an outer surface. The braided layer 135 is disposed between the first layer 131 and the second layer 133 such that, the first layer 131 is coupled to the outer surface of the braided layer 135 and the second layer 133 is coupled to the inner surface of the braided layer 135. The first layer 131 and the second layer 133 may be coupled to the braided layer 135 using a coupling technique, including but not limited to, adhesive bonding, heat shrinking, ultrasonic bonding crimping, etc. In an embodiment, the first layer 131 and the second layer 133 are coupled to the braided layer 135 using heat shrinking. The braided layer 135 includes a plurality of filaments braided to form a braided structure (shown in Fig. 3a). The filaments may be braided in a predefined braiding pattern such as, without limitation, 1:1, 1:2, 2:1, etc. In an embodiment, the filaments are braided in a 1:1 braiding pattern. The filaments may be braided over each other such that each pair of adjacent filaments form an angle A at the point of intersection. The angle A may range between 20 degrees and 60 degrees. In an embodiment, the angle A is 40 degrees. The filaments may be made of material including, but not limited to, nitinol, stainless steel (e.g., SS314, SS304), etc. In an embodiment, the filaments are made of SS304. The braided layer 135 reinforces the proximal portion 130 by providing additional radial strength to the proximal portion 130 of the outer sheath 100 to withstand the stresses developed in the proximal portion 130, during motion of the outer sheath 100 within the curves of the vasculature of the patient. This enhances the durability of the proximal portion 130 and making it resistant to kinking.
[0039] Although the first layer 131, the second layer 133 and the braided layer 135 are explained separately, the first layer 131, the second layer 133 and the braided layer 135 of the proximal portion 130 may be fused into a single integral structure through the heating process thereby, forming the proximal portion 130 of the outer sheath 100.
[0040] Optionally, the proximal portion 130 may include one or more additional layers provided inside the second layer 133 and/or outside the first layer 131.
[0041] Moving on to Fig. 4, in an embodiment, the proximal portion 130 smoothly transitions into the distal portion 110 via the middle portion 150 of the outer sheath 100. The middle portion 150 is positioned at the junction of the distal portion 110 and the proximal portion 130. The middle portion 150 couples the distal portion 110 and the proximal portion 130. In an embodiment, the middle portion 150 includes an outer layer (not shown) coupling the first layer 131 of the proximal portion 130 with the outer layer 113 of the distal portion 110. The middle portion 150 also includes an inner layer (not shown) coupling the second layer 133 of the proximal portion 130 transitions to the inner layer 111 of the distal portion 110. The middle portion 150 has a tapered profile. The diameter of the middle portion 150 decreases from a distal end to a proximal end of the middle portion 150. Since the first diameter of the distal portion 110 is greater than the second diameter of the proximal portion 130, the middle portion 150 provides a smooth transition between the distal potion 110 and the proximal portion 130.
[0042] The length of the middle portion 150 may depend upon the difference between the outer diameters of the distal portion 110 and the proximal portion 130 and a desired gradient for transitioning from the proximal portion 130 to the distal portion 110. In an embodiment, the length of the middle portion 150 may range between 7 mm and 15 mm. In an example implementation, the length of the middle portion 150 is 10 mm. The middle portion 150 may include a braided structure or may include a coil (e.g., similar to the coil 115). In an embodiment, the middle portion 150 is braided. The braiding structure of the middle portion 150 may be similar to the braiding structure of the proximal portion 130 and is not repeated for the sake of brevity.
[0043] Though the structure of the outer sheath 100 is explained in reference with three portions – the distal portion 110, the proximal portion 130 and the middle portion 150, the outer sheath 100 may be manufactured as a single structure.
[0044] Now an exemplary method 500 of manufacturing the outer sheath 100 is explained with reference to Fig. 5.
[0045] At step 501, inner layers of the outer sheath 100, namely, the inner layer 111 of the distal portion 110, the first layer 131 of the proximal portion 130 and the inner layer of the middle portion 150 are formed by an extrusion process. In an embodiment, layer of a desired material including, but not limited to, PTFE, PEEK, PU, PEBAX, etc., having a desired thickness is extruded over a mold e.g., a tapered rod), forming the inner layer 111 of the distal portion 110, the first layer 131 of the proximal portion 130 and the inner layer of the middle portion 150 the outer sheath 100. The mold has a shape and dimensions corresponding to an inner-most surface of the proximal portion 130, the distal portion 110 and the middle portion 150. In an embodiment, portions of the mold corresponding to the proximal portion 130 and the distal portion 110 have different diameters as described herein.
[0046] At step 502, the coil 115 is formed on the inner layer 111 of the distal portion 110. A wire of a desired material including, but not limited to, nitinol, stainless steel (e.g., SS314, SS304), and so forth, is wound over the inner layer 111 of the distal portion 110 through a coiling process to form the coil 115.
[0047] At step 503, the braided layer 135 is formed on the second layer 133 of the proximal portion 130. In an embodiment, a plurality of filaments is braided over the second layer 133 of the proximal portion 130 in a predefined pattern such as, without limitation 1:1, 1:2, 2:1, etc., to form the braided layer 135 over the second layer 133. Optionally, filaments may be braided over the inner layer of the middle portion 150 to form the braided structure of the middle portion 150.
[0048] At step 504, outer layers of the outer sheath 100, namely, the outer layer 113 of the distal portion 110, the first layer 131 of the proximal portion 130 and the outer layer of the middle portion 150 are formed using an extrusion process. In an embodiment, a desired material including, but not limited to PTFE, PEEK, PU, PEBAX, (polyamide) PA, VESTAMID® and so forth, is extruded over the coil 115, the braided layer 135, and the braided structure of the middle portion 150, for a desired thickness, forming the outer layer 113 of the distal portion 110, the first layer 131 of the proximal portion 130 and the outer layer of the middle portion 150 of the outer sheath 100.
[0049] At step 505, the layers of the outer sheath 100, namely, the inner layers and the outer layers of the outer sheath 100 as well as the coil 115, the braided layer 135 and the braided structure of the middle portion 150 are fused together using a heat shrinking process. In an embodiment, the inner layers and the outer layers of the outer sheath 100 as well as the coil 115, the braided layer 135 and the braided structure of the middle portion 150 as formed in preceding steps are heated to a pre-defined temperature ranging from 220°C to 320°C. In an embodiment, aforementioned components are heated to 250°C. The pre-defined temperature is maintained until the inner layers and the outer layers of the outer sheath 100 shrink by a pre-defined ratio, for example, 2:1, 3:1, or 6:1. In an exemplary embodiment, the pre-defined temperature is maintained until the inner layers and the outer layers of the outer sheath 100 shrink by 3:1. The shrinkage of the inner layers and the outer layers ensure that the inner layers and the outer layers of the outer sheath 100 are fused with corresponding coil 115, or the braided layer 135 or the braided structure. A constant pressure is maintained during the heating process to ensure uniform shrinkage of the material of the outer layers and the inner layers of the catheter 100. The aforesaid fused components are cooled, for example, to room temperature, to solidify the shape.
[0050] At step 506, the mold is removed.
[0051] At step 507, a desired length of the layers is cut to yield the outer sheath 100.
[0052] Though the outer sheath 100 of the present disclosure is described herein in the context of deploying a stent graft, it should not be considered as limiting. The teachings of the present disclosure are applicable to an outer sheath for delivering and/or deploying other devices such as, without limitation, an atherectomy device, stents, coils, implants, and delivery system etc.
[0053] 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. , Claims:WE CLAIM
1. An outer sheath (100) comprising:
a. a distal portion (110) having a first diameter; and
b. a proximal portion (130) having a second diameter;
c. a middle portion (150) coupling the distal portion (110) and the proximal portion (130);
d. wherein first diameter is greater than the second diameter.
2. The outer sheath (100) as claimed in claim 1, wherein the middle portion (150) has a tapered profile.
3. The outer sheath (100) as claimed in claim 1, wherein the distal portion (110) includes a tip (117) tapered at an angle with respect to a longitudinal axis of the outer sheath 100, wherein the angle ranges between 4 degrees and 7 degrees.
4. The outer sheath (100) as claimed in claim 3, wherein the tip (117) includes a radiopaque coating.
5. The outer sheath (100) as claimed in claim 1, wherein the distal portion (110) includes a coil (115) having an inner surface and an outer surface.
6. The outer sheath (100) as claimed in claim 5 wherein the coil (115) has a predefined pitch, wherein the pitch ranges between 0.3 mm and 0.8 mm.
7. The outer sheath (100) as claimed in claim 5, wherein the coil (115) extends at least partially along length of the distal portion (110).
8. The outer sheath (100) as claimed in claim 5, wherein the distal portion (110) includes an inner layer (111) coupled to the inner surface of the coil (115) and an outer layer (113) coupled to the outer surface of the coil (115).
9. The outer sheath (100) as claimed in claim 1, wherein the proximal portion (130) includes a braided layer (135) having an outer surface and an inner surface, the braided layer (135) comprising a plurality of filaments braided to form a braided structure.
10. The outer sheath (100) as claimed in claim 9, wherein the filaments of the braided layer (135) are braided in a pre-defined pattern comprising one of: 1:1, 1:2, 2:1.
11. The outer sheath (100) as claimed in claim 9, wherein the proximal portion (130) comprises:
a. a first layer (131) coupled to the outer surface of the braided layer (135); and
b. a second layer (133) coupled to the inner surface of the braided layer (135).
12. The outer sheath (100) as claimed in claim 9, wherein the filaments are braided over each other such that each adjacent pair of filaments forms an angle A at the point of intersection, wherein the angel A ranges between 20 degrees and 60 degrees.
13. An outer sheath (100) comprising:
a. a distal portion (110);
b. a proximal portion (130) coupled to the distal portion (110); and
c. wherein the distal portion (110) includes a coil (115) having an inner surface and an outer surface; and
d. wherein the proximal portion (130) is braided.
14. The outer sheath (100) as claimed in claim (13), wherein the coil (115) extends at least partially along length of the distal portion (110).
15. The outer sheath (100) as claimed in claim 13, wherein the distal portion 110 includes a tip 117 tapered at an angle with respect to a longitudinal axis of the outer sheath 100, wherein the angle ranges between 4 degrees and 7 degrees.
16. The outer sheath (100) as claimed in claim 15 wherein the tip (117) includes a radiopaque coating.
17. The outer sheath (100) as claimed in claim 13, wherein the proximal portion (130) includes a braided layer (135) having an outer surface and an inner surface, the braided layer (135) comprising a plurality of filaments braided to form a braided structure.
18. The outer sheath (100) as claimed in claim 17, wherein the filaments of the braided layer (135) are braided in a pre-defined pattern comprising one of: 1:1, 1:2, or 2:1.
19. The outer sheath (100) as claimed in claim 17, wherein the proximal portion (130) comprises:
a. a first layer (131) coupled to the outer surface of the braided layer (135); and
b. a second layer (133) coupled to the inner surface of the braided layer (135).
20. The outer sheath (100) as claimed in claim 17, wherein the filaments are braided over each other such that two filaments form an angle A at the point of intersection, wherein the angle A ranges from between 20 degrees and 60 degrees.
21. The outer sheath (100) as claimed in claim 13, wherein the coil (115) has a predefined pitch, wherein the pitch ranges between 0.3 mm and 0.8 mm.
22. The outer sheath (100) as claimed in claim 13, wherein the distal portion (110) includes an inner layer (111) coupled to the inner surface of the coil (115) and an outer layer (113) coupled to the outer surface of the coil (115).
23. The outer sheath (100) as claimed in claim 13, wherein the distal portion (110) has a first diameter and the proximal portion (130) has a second diameter, wherein the first diameter is greater than the second diameter.
24. The outer sheath (100) as claimed in claim 23, wherein the outer sheath (100) comprises a middle portion (150) coupling the proximal portion (130) and the distal portion (110).