Claims:WE CLAIM:
1. A delivery system (100) comprising:
• an inner tube (30) including a proximal end (3b’) and a distal end (3a’), the inner tube (30) including at least one stent (30) mounted towards the distal end (3a’);
• an outer sheath (20) being co-axially placed over the inner tube (30), the outer sheath (20) being capable of relative movement with respect to the inner tube (30); and
• a handle kit (10) coupled to the proximal end (3b’) of the inner tube (30), the handle kit (10) further comprising:
o at least one loop (12) having a lumen,
o a guide tube (12a) placed within the lumen of the loop (12), the guide tube (12a) houses the outer sheath (20) when the outer sheath (20) is placed inside the loop (12);
o a roller (14) being operatively coupled to the outer sheath (20), the roller (14) being capable of rotating in at least one of a clockwise or an anti-clockwise direction at a time; and
wherein, in the initial position, the outer sheath (20) is placed over the inner tube (30) carrying the at least one stent (30a), wherein on application of a pull force by the roller (14), the outer sheath (20) is pulled inside the guide tube (12a) thereby expanding the stent (30a) for delivery.
2. The delivery system (100) as claimed in claim 1 wherein the at least one crimped stent (30a) includes a stent (30a) having a length of 06 x 60mm.
3. The delivery system (100) as claimed in claim 1 wherein the inner tube (30) includes a soft tip (30b) at the distal end (3a’).
4. The delivery system (100) as claimed in claim 1 wherein the inner tube (30) includes a pusher piston.
5. The delivery system (100) as claimed in claim 1 wherein the outer sheath (20) includes at least two radio-opaque markers (20a, 20b).
6. The delivery system (100) as claimed in claim 1 wherein the guide tube (12a) and the loop (12) are made of high-density polyethylene (HDPE), nitinol, stainless steel or cobalt chromium.
7. The delivery system (100) as claimed in claim 1 wherein the roller (14) is coupled to the outer sheath (20) using a coupling means (14c). , 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:
DELIVERY SYSTEM FOR SELF EXPANDING STENTS

2. APPLICANT:
Meril Life Sciences Pvt. Ltd., an Indian company of the address Survey No. 135/139 Bilakhia House, Muktanand Marg, Chala, Vapi- 396191, Gujarat, 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, to a delivery device for a self-expanding peripheral stent.
BACKGROUND
[002] Self-expanding stents are widely used in body vessels, ducts or other body lumens to restore normal blood flow. The introduction and placement of self-expanding stents is facilitated using stent delivery systems. Self-expanding stents expand radially to an original diameter from a compressed condition when released from their delivery systems, subsequently exerting a radial force at a treatment site to re-establish patency of a body lumen or duct.
[003] Despite the technological advancement in the stent platforms and related techniques, targeting long lesions still remains a major challenge. Different intervention techniques to treat long lesions include use of multiple overlapping stents, a single long stent, etc. Conventionally, the use of multiple stents having different lengths requires multiple delivery devices with different lengths to be compatible with the said stents. Such a provision increases the procedural time, stent migration, vessel injury and unnecessary stent stacking, etc.
[004] As opposed to using multiple stents, longer stents increase revascularization rates and lower the chances of thrombosis. Even though the use of a single long stent comes across as a better solution, however, none of the available systems have proven to hold merit by presenting better outcomes. One of the reasons behind the aforesaid is the use of inefficient delivery systems for deploying long stents.
[005] Conventionally, the delivery systems used for self-expanding stent deployment are based on reciprocating mechanism. Such systems primarily include an outer sheath, a stent driver, and a thumb slide. The outer sheath constrains the stent until delivery. The stent driver pushes the stent out of the outer sheath. The thumb slide is connected to the stent driver internally. The reciprocation of the thumb slide located on the handle, helps to advance the stent out of the outer sheath. The number of thumb slide cycles required increase with the increase in stent length. While this mechanism is easy to use, it leads to prolonged procedural time for stents having longer lengths and consequently chances of stent related issues such as high migration, stacking and vessel injury may also arise.
[006] Further, in conventional delivery systems, the outer sheath remains fixed while the inner sheath moves forward towards the targeted lesions. Due to uneven and improper movement of the inner sheath, the stent(s) may be stacked which in turn may cause shortening of the deployable length of the stent thereby leading to incomplete coverage of the target site. Further, the conventional systems require multiple repositioning and re-sheathing steps during stent deployment to place the stent at the accurate target site.
[007] Taking into account the disadvantages of the presently available stent delivery systems, there is a need for an invention that supports placement of longer stents and offers a reliable and faster deployment mechanism.
SUMMARY
[008] The present invention relates to a delivery system having an inner tube including a proximal end and a distal end. The inner tube includes at least one stent mounted towards the distal end. The delivery system further includes an outer sheath being co-axially placed over the inner tube. The outer sheath is capable of relative movement with respect to the inner tube. A handle kit is coupled to the proximal end of the inner tube. The handle kit further includes at least one loop having a lumen, a guide tube placed within the lumen of the loop and a roller being operatively coupled to the outer sheath. The guide tube houses the outer sheath when the outer sheath is placed inside the loop. The roller is capable of rotating in at least one of a clockwise or an anti-clockwise direction at a time. In the initial position, the outer sheath is placed over the inner tube carrying the at least one stent. On application of a pull force by the roller, the outer sheath is pulled inside the guide tube thereby expanding the stent for delivery.
[009] 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
[0010] 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.
[0011] FIG. 1 depicts a delivery system 100 in accordance with an embodiment of the present invention.
[0012] FIG. 1A depicts the handle kit 10 in accordance with an embodiment of the present invention.
[0013] FIG. 1B depicts the roller 14 in accordance with an embodiment of the present invention.
[0014] FIG. 1C depicts the outer sheath 20 placed within the handle 10’ in accordance with an embodiment of the present invention.
[0015] FIG. 1D depicts a perspective view of the outer sheath 20 in accordance with an embodiment of the present invention.
[0016] FIG. 1D1 depicts a perspective view of the outer sheath 20 in accordance with an alternate embodiment of the present invention.
[0017] FIG. 1E depicts the inner tube 30 in accordance with an embodiment of the present invention.
[0018] FIG. 1F depicts the inner tube 30 along with a crimped stent with an embodiment of the present invention.
[0019] FIG. 2 illustrates the steps involved in the deployment process via the delivery system 100 in accordance with an embodiment of the present invention.
[0020] FIGs. 2A-2D depicts the stages in the deployment process in accordance with an embodiment of the present invention.
[0021] FIGs. 3A-B depicts an exemplary performance data of the delivery system 100 in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0022] 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.
[0023] 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.
[0024] 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 and apparatus can be used in combination with other systems, and apparatuses.
[0025] 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.
[0026] In accordance with the present disclosure, a delivery system for deployment of a self-expanding stent at a target site is disclosed. The target site of the present invention may include a lesion of a diseased peripheral, biliary or coronary vasculature. The delivery system of the present invention allows controlled, accurate, easy and fast deployment of the self-expanding stent.
[0027] The delivery system is used for smooth deployment of one or more self-expanding stents. The delivery system includes various components such as an outer sheath, an inner tube and a roller mechanism. The outer sheath and the inner tube are co-axially placed in such a manner that the outer sheath is mounted over the inner tube. The stent is pre-loaded within the outer sheath at the distal end of the inner tube.
[0028] The inner tube of the present invention is fixed while the outer sheath is capable of linear motion. The outer sheath of the present invention moves relative to the inner tube thereby facilitating smooth, easy and controlled deployment of stent. Further, repositioning and/or re-sheathing of the stent multiple times is prevented due to the fixed position of the inner tube relative to the outer sheath. This further reduces the chances of unnecessary stent stacking and stent migration from the treatment site while deployment of the stent. Further, the chances of vessel injury are significantly reduced as the stent loaded over the inner tube is not pushed out of the delivery system while deployment.
[0029] The linear motion of the outer sheath is achieved by rotating a roller of a roller mechanism in a clockwise or an anticlockwise direction. The rotation of the roller in an anti-clockwise direction causes backward motion of the outer sheath thereby expanding the stent. Owing to such a backward motion, the outer sheath is accommodated within one or more loops. The presence of loops helps to accommodate long outer sheaths that enclose multiple stents of varying lengths or a single long stent, within the delivery system. Hence, the requirement of multiple deployments is eliminated and the procedural time is reduced.
[0030] Now referring to figures, FIG. 1 of the present invention discloses a delivery system 100. The delivery system 100 is used for deployment of one or more self-expanding stents at a target site. The self-expanding stent(s) may be an intravascular stent which may be deployed in a lesion of a diseased peripheral, biliary or coronary vasculature.
[0031] As shown in FIG. 1, the delivery system 100 extends from a proximal end 100a to a distal end 100b and defines a longitudinal axis ‘ab’. The delivery system 100 may include a plurality of components that are aligned along the longitudinal axis ‘ab’ of the delivery system 100. The plurality of components includes, without limitation, a handle kit 10 and an outer sheath 20 which encloses a stent mounted over an inner tube (not shown). The inner tube is provided with a soft tip 30b which forms the distal end 100b of the delivery system 100.
[0032] As evident from FIG. 1, the handle kit 10 is disposed towards the proximal end 100a of the delivery system 100. The handle kit 10 includes various components that function in a synchronized manner to operate and control the process of stent deployment via the delivery system 100.
[0033] The handle kit 10 includes a handle 10’. The handle 10’ is structured to provide proper grip to the user for easy and controlled deployment of the stent. Further, the handle 10’ is also employed for housing other components of the handle kit 10. The shape and dimensions i.e. length/diameter/width of the handle 10’ may be selected so that maximum ease and comfort are provided to the user and at the same time, the components are easily housed within the handle 10’.
[0034] The handle 10’ may be made up of, without limitation, ABS (acrylonitrile butadiene styrene) plastic, polycarbonate, HDPE (high density polyethylene), polypropylene or polyethylene. In the present embodiment, the handle 10’ is made up of ABS.
[0035] The handle 10’ may include two adjacently placed sections i.e. a proximal section 10a and distal section 10b. The proximal section 10a of the handle 10’ is disposed at the proximal end 100a of the delivery system 100. The length of the proximal section 10a may range between 100mm to 200mm. In an embodiment, the length of the proximal section 10a is 140mm.
[0036] As shown in FIG. 1, the proximal section 10a includes one or more loops 12. The loops 12 may outwardly extend from the handle 10’ to at least one of the sides of the handle 10’. The number as well as dimensions i.e. diameter of the loops 12 may depend upon the length of the outer sheath 20. In case of multiple loops 12, the diameter of the loops 12 may be same or different. The diameter of the loop(s) 12 may range between 10mm to 15mm. In an embodiment, the diameter of the loop 12 is 10mm. The number of loops 12 may range between one to three loops. In an exemplary embodiment as depicted in FIG. 1, the delivery system 100 includes a single loop 12 disposed at one side of the handle 10’. The length of the loop 12 may range from 500 mm to 650 mm. In an embodiment, the length of the loop 12 is 600mm. The loop(s) 12 may be made from a pre-defined material such as high-density polyethylene (HDPE), nitinol, stainless steel, cobalt chromium, etc. In an embodiment, the loop(s) 12 is made of high-density polyethylene (HDPE).
[0037] As illustrated in FIG. 1A, the loop(s) 12 extends from the proximal section 10a of the handle 10’, coils up outside the handle 10’ and reenters the handle 10’ to extends till the proximal end 100a of the delivery system 100. The loop(s) 12 may exit and/or enter the handle 10’ via at least two holes o1, o2 provided within the handle 10’.
[0038] As shown in FIG. 1A, the loop(s) 12 of the present invention may include a lumen which houses a co-axial guide tube 12a. The guide tube 12a may resemble a structure similar to the one or more loops 12. The guide tube 12a extends from the proximal section 10a of the handle 10’ and coils up outside the handle 10’ within the one or more loops 12. Post forming coils within the loop(s) 12, the guide tube 12a reenters the handle 10’ and further extends till the proximal end 100a of the delivery system 100. The guide tube 12a may exit and/or enter the handle 10’ via at least two holes o1, o2 provided within the handle 10’.
[0039] Such arrangement of the guide tube 12a houses the outer sheath 20 and provides an area for the movement of the outer sheath 20 at the time of deployment of the stent 30a. Further, the guide tube 12a ensures that the outer sheath 20 moves freely without any damage.
[0040] The guide tube 12a may be made from a pre-defined material such as, high-density polyethylene (HDPE) nitinol, stainless steel, cobalt chromium, etc. In an embodiment, the guide tube 12a is made from HDPE.
[0041] The dimensions of the guide tube 12a may be dependent upon the dimensions of the outer sheath 20. The total length of the guide tube 12a may range from 450-700mm.In an embodiment, the total length of the guide tube 12a is 550 mm. The diameter of the guide tube 12a may range from 1.4 mm to 1.8 mm. In an embodiment, the diameter of the guide tube 12a is 1.6 mm. The outer diameter of the guide tube 12a ranges from 1.4 mm to 1.8 mm. In an embodiment, the outer diameter is 1.6mm.
[0042] Further, the handle 10’ may include a roller 14 as shown in FIG. 1A which may be disposed at a pre-defined location. In an embodiment, the roller 14 is disposed at the junction of the proximal section 10a and the distal section 10b of the handle 10’. The roller 14 may be a knob type structure as clearly shown in FIG. 1B. The roller 14 may be made up of without limitation polycarbonate rubber, ABS, HDPE, PP, etc. In present embodiment, roller 14 is made of polycarbonate rubber.
[0043] The roller 14 may be attached to the handle 10’ with the help of any conventional technique such as using a shaft pin 14a. As shown in FIG. 1B, the roller 14 may include a unidirectional needle bearing 14b. The unidirectional needle bearing 14b houses the shaft pin 14a. The shaft pin 14a may be made up of without limitation medical grade SS (Stainless Steel), ABS (Acrylonitrile butadiene styrene) plastic, polycarbonate material, etc.
[0044] The roller 14 is configured to be manually rotated by the user in a clockwise or an anti-clockwise direction to cause linear motion of the outer sheath 20. The roller 14 may be operatively coupled to the outer sheath 20 via a coupling means 14c as shown in FIG. 1C. In an embodiment, the coupling means 14c corresponds to one or more strings. The string(s) may be made of polydioxanone, nylon, nitinol, stainless steel or any other material having flexibility and strength. In present embodiment, the string is made of nylon. The length of the string(s) ranges from 550 mm to 650 mm. In an embodiment, the length of the string is 590mm.
[0045] As evident from FIG. 1C, one end of the coupling means 14c may be attached with the roller 14 and the other end may be attached with the outer sheath 20. The attachment of the coupling means 14c with the outer sheath 20 and the roller 14 may be done via any conventional mechanism such as a cap or a medical grade bonding like glue, etc. The coupling means 14c may be tightly fixed with the help of the unidirectional needle bearing 14b in such a way that the roller 14 is able to rotate freely.
[0046] The distal section 10b of the handle 10’ may be connected with an inner tube. The inner tube is covered with the outer sheath 20. The enlarged views of the outer sheath 20 enclosing the inner tube having a single stent 30a and two stents (stent -1, stent -2)are depicted in FIGs. 1D and 1D1.
[0047] The length of the outer sheath 20 may range from 600 mm to 1000 mm. In an embodiment, the length of the outer sheath 20 is 800mm. The diameter of the outer sheath 20 may range from 5 Fr to 10 Fr.
[0048] The outer sheath 20 may be a multi-layered structure. In an embodiment, the outer sheath 20 is a dual layered tube having an inner layer and an outer layer. The said layers may be made of, polyether block amide, polytetrafluoroethylene, polyether etherketone, low density polythene (LDPE), high density polythene (HDPE) polymers, etc. In an embodiment, the inner layer of the outer sheath 30 is made of polytetrafluoroethylene (PTFE) while the outer layer is made from polyether block amide.
[0049] The outer sheath 20 may be provided with a plurality of markers. As shown in FIG. 1D, two radiopaque markers 20a, 20b are provided over the outer sheath 20. The said markers 20a, 20b may include any pre-defined shape known in the art. In an embodiment, the markers 20a, 20b have circular shape. The markers 20a, 20b may be made of any conventional radiopaque material such as without limitation, platinum, tungsten, titanium or gold. In an embodiment, the markers 20a, 20b are made of platinum. The dimensions of the markers 20a, 20b may be pre-defined. In an embodiment, the markers 20a, 20b have a length of 2 mm each.
[0050] The markers 20a, 20b may indicate the deployed length and position of the stent. Hence, the markers 20a, 20b help to determine the lesion area that is to be covered at the time of deployment of the stent for accurate positioning of the same.
[0051] The perspective view of the inner tube 30 is shown in FIG. 1E. The inner tube 30 may define a lumen which acts as a passageway for a guide wire. The inner tube 30 passes coaxially within the outer sheath 20. In present embodiment, the inner tube 30 extends from the distal section 10b of the handle kit 10 till the distal end 100b of the delivery system 100. The inner tube 30 helps to mount the stent 30a in crimped condition as shown in FIG. 1F.
[0052] The inner tube 30 may be made by any pre-defined technique. As per an exemplary embodiment, the inner tube 30 is a braided reinforced tube having multiple layers. The inner tube 30 may include two layers i.e. an inner layer and an outer layer. The inner and/or outer layers of the inner tube 30 may be made from polyether block amide, PTFE, etc. In an embodiment, the inner layer is made from polytetrafluoroethylene while the outer layer is made of polyamide. The outer diameter of the inner tube 30 may range from 0.6 mm to 1.6 mm. In an embodiment, the outer diameter is 0.9mm. The length of the inner tube 30 may range from 1200 mm to 1800 mm. In an embodiment, the length of the inner tube 30 is 1400 mm.
[0053] The inner tube 30 includes a distal end 3a’ and a proximal end 3b’ as shown in FIG. 1E. The proximal end 3b’ of the inner tube 30 is coupled to the handle kit 10. The distal end 3a’ is provided with the soft tip 30b. The soft tip 30b helps to the delivery system 100 to navigate through the vessels without any damage. The soft tip 30b may be made of materials such as without limitation pebax, nylon, HDPE, etc. In an embodiment, the soft tip 30b is made of radiopaque polyether block amide for higher visibility during stent deployment under fluoroscopic vision.
[0054] As shown in FIG. 1E, the inner tube 30 is provided with a pusher piston 30c over the inner tube 30. The pusher piston 30c may be attached to inner lumen 30 via any conventional technique such as bonding, heat treatment or any other bonding method using an adhesive.
[0055] The pusher piston 30c may be a tubular structure which is used as a bumper. The pusher piston 30c helps to push the stent 30a towards the target site at the time of stent deployment.
[0056] The pusher piston 30c may be made of any pre-defined material such as without limitation nylon, polyether block amide, etc. In present embodiment, the pusher piston 30c is made of polyether block amide.
[0057] The location of the disposition of the pusher piston 30c may depend upon the length of the crimped stent 30a. The pusher piston 30c may be disposed before the proximal end of the crimped stent 30a i.e. the end of the crimped stent 30a that faces the distal section 10b of the handle kit 10.
[0058] The length of the pusher piston 30c may range from 7 mm to 17 mm. In an embodiment, the length of the pusher piston 30c is 12mm. In an alternate embodiment, as per requirement, a second piston such as a retract piston may also be attached to the inner tube 30 to help in retracting the stent back within the outer sheath. It may be disposed at a distance of 10 mm to 12 mm, ahead from pusher piston 30c.
[0059] FIG. 2 depicts a method 200 to deploy the stent using the delivery system 100. For delivery at a treatment site, the crimped stent 30a is pre-loaded over the delivery system 100. In initial position, the outer sheath 20 is placed over the inner tube 30 carrying the stent 30a. At step 201, the pre-loaded delivery system 100 is advanced over a guide wire to the treatment site as shown in FIG. 2A. The stent 30a may have a crimped length and a deployed length. In an embodiment, the crimped length of the stent 30a is three times the deployed length. The radiopaque markers 20a, 20b may mark the length of the deployed stent 30a at the treatment site, which helps a physician in positioning the delivery system 100 at the time of deployment. In an embodiment, the physician positions the distal marker 20b 5% to 10% ahead of the treatment site.
[0060] At step 203, once the delivery system 100 reaches the treatment site, the roller 14 is rotated in a clockwise direction. The clockwise rotation of the roller 14 results in retraction of the outer sheath 20. As the stent 30a is a self-expanding stent, retraction of the outer sheath 20 cases exposure of the stent 30a as well as simultaneous expansion of the crimped stent 30a for deployment as shown in FIGs. 2B & 2C. The retracted outer sheath 20 positions itself within the handle 10’ and further into the guide tube 12a/loop(s) 12.
[0061] Hence, on rotation of the roller 14, a pull force is applied by the roller 14 on the outer sheath 20 which causes the outer sheath 20 to be pulled inside the guide tube 12a thereby expanding the stent 30a for delivery.
[0062] The user may reposition the delivery system 100 at any time before complete expansion of the stent 30a. The user may resheath the stent 30a by rotating the roller 14 in an opposite direction and moving the outer sheath 20 forward.
[0063] At step 205, the stent 30a is completely exposed and hence, expands wholly to attain its deployed length and diameter at the treatment site as shown in FIG. 2D.
[0064] Once, the stent 30a is deployed, the delivery system 100 may be retraced and withdrawn.
[0065] The above invention is explained with the help of below examples:
[0066] Example 1
[0067] A pre-loaded delivery system with a 6.00 x 60mm stent size was used to deploy a stent in a mock (Silicone) artery model. The delivery system included a reciprocating mechanism for deployment of the stent. The delivery system further included an outer sheath, a guidewire lumen, a soft tip, a handle, a thumb slide, a thumb lock, a SS tube, etc. the stent deployment was achieved by reciprocation of the thumb slide located on the handle.
[0068] The thumb slide cycles were observed to be 10 times for the stent having a length of 110mm and hence the procedural time was extended by 10 to 15 minutes. Further, it was observed that the stent migrated above 01cm to 02cm of the target lesion. Other issues such as stacking and uneven deployed surface were also observed due to improper delivery system. The trackability and pushability of the stent was performed and found to have a value of around 4.0N force.
[0069] Example 2
[0070] A roller mechanism based delivery system was used to deploy a stent. The length of loaded stent was 6.00x 60 mm. The delivery system included an outer sheath, an inner tube, a handle, a roller, a guide tube, a loop, a bearing (one side drive needle bearing), a shaft pin, etc.
[0071] The roller rotating cycle was up to 05 times for 20mm-150mm stent length because the roller design is specially prepared according to the 06 x 60mm stent length. It was observed that easy and accurate placement of the stent at the target site was achieved. No repositioning and stent migration was observed. The trackability and pushability of the stent was performed and found to have a value of 3.5N of force with clearance of bending, buckling or kinking test of the pre-loaded peripheral stent delivery system as shown in FIGs. 3A & 3B.
[0072] The delivery system of example 2 was found to be more flexible than the delivery system of example 1. Also, the difference trackability and pushability of the delivery systems elaborated in the examples indicates that more force is required to advance the delivery system of example 1 than example 2.
[0073] 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.